Title: Antiplatelet Effect of Daphnetin Is Regulated by cPLA(2)-Mediated Thromboxane A(2) Generation in Mice Chaudhary PK, Kim S Ref: Int J Mol Sci, 24:, 2023 : PubMed
Coumarin derivatives have been recognized for their antithrombotic, anti-inflammatory, and antioxidant properties, and daphnetin is one of the natural coumarin derivatives isolated from Daphne Koreana Nakai. Although the pharmacological value of daphnetin is well documented in diverse biological activities, its antithrombotic effect has not been studied to date. Here, we characterized the role and underlying mechanism of daphnetin in the regulation of platelet activation using murine platelets. In order to check the effect of daphnetin on platelet function, we first measured the effect of daphnetin on platelet aggregation and secretion. Collagen-induced platelet aggregation and dense granule secretion were partially inhibited by daphnetin. Interestingly, 2-MeSADP-induced secondary waves of aggregation and secretion were completely inhibited by daphnetin. It is known that 2-MeSADP-induced secretion and the resultant secondary wave of aggregation are mediated by the positive feedback effect of thromboxane A(2) (TxA(2)) generation, suggesting the important role of daphnetin on TxA(2) generation in platelets. Consistently, daphnetin did not affect the 2-MeSADP-induced platelet aggregation in aspirinated platelets where the contribution of TxA(2) generation was blocked. Additionally, platelet aggregation and secretion induced by a low concentration of thrombin, which is affected by the positive feedback effect of TxA(2) generation, were partially inhibited in the presence of daphnetin. Importantly, 2-MeSADP- and thrombin-induced TxA(2) generation was significantly inhibited in the presence of daphnetin, confirming the role of daphnetin on TxA(2) generation. Finally, daphnetin significantly inhibited 2-MeSADP-induced cytosolic phospholipase A(2) (cPLA(2)) and ERK phosphorylation in non-aspirinated platelets. Only cPLA(2) phosphorylation, not ERK phosphorylation, was significantly inhibited by daphnetin in aspirinated platelets. In conclusion, daphnetin plays a critical role in platelet function by inhibiting TxA(2) generation through the regulation of cPLA(2) phosphorylation.
Lipases, which catalyze the hydrolysis of long-chain triglycerides, diglycerides, and monoglycerides into free fatty acids and glycerol, participate in various biological pathways in fungi. In this study, we examined the biological functions and regulatory mechanisms of fungal lipases via two approaches. First, we performed a systemic functional characterization of 86 putative lipase-encoding genes in the plant-pathogenic fungus Fusarium graminearum. The phenotypes were assayed for vegetative growth, asexual and sexual reproduction, stress responses, pathogenicity, mycotoxin production, and lipase activity. Most mutants were normal in the assessed phenotypes, implying overlapping roles for lipases in F. graminearum. In particular, FgLip1 and Fgl1 were revealed as core extracellular lipases in F. graminearum. Second, we examined the lipase activity of previously constructed transcription factor (TF) mutants of F. graminearum and identified three TFs and one histone acetyltransferase that significantly affect lipase activity. The relative transcript levels of FgLIP1 and FGL1 were markedly reduced or enhanced in these TF mutants. Among them, Gzzc258 was identified as a key lipase regulator that is also involved in the induction of lipase activity during sexual reproduction. To our knowledge, this study is the first comprehensive functional analysis of fungal lipases and provides significant insights into the genetic and regulatory mechanisms underlying lipases in fungi. IMPORTANCE Fusarium graminearum is an economically important plant-pathogenic fungus that causes Fusarium head blight (FHB) on wheat and barley. Here, we constructed a gene knockout mutant library of 86 putative lipase-encoding genes and established a comprehensive phenotypic database of the mutants. Among them, we found that FgLip1 and Fgl1 act as core extracellular lipases in this pathogen. Moreover, several putative transcription factors (TFs) that regulate the lipase activities in F. graminearum were identified. The disruption mutants of F. graminearum-lipase regulatory TFs all showed defects in sexual reproduction, which implies a strong relationship between sexual development and lipase activity in this fungus. These findings provide valuable insights into the genetic mechanisms regulating lipase activity as well as its importance to the developmental stages of this plant-pathogenic fungus.
Title: Acetylcholine titre regulation by non-neuronal acetylcholinesterase 1 and its putative roles in honey bee physiology Kim S, Seong KM, Lee SH Ref: Insect Molecular Biology, :, 2023 : PubMed
Similar to other insects, honey bees have two acetylcholinesterases (AChEs), AmAChE1 and AmAChE2. The primary catalytic enzyme for acetylcholine (ACh) hydrolysis in synapses is AmAChE2, which is predominantly expressed in neuronal tissues, whereas AmAChE1 is expressed in both neuronal and non-neuronal tissues, with limited catalytic activity. Unlike constitutively expressed AmAChE2, AmAChE1 expression is induced under stressful conditions such as heat shock and brood rearing suppression, but its role in regulating ACh titre remains unclear. In this paper, to elucidate the role of AmAChE1, the expression of AmAChE1 was suppressed via RNA interference (RNAi) in AmAChE1-induced worker bees. The ACh titre measurement following RNAi revealed that the expression of AmAChE1 downregulated the overall ACh titre in all tissues examined without altering AmAChE2 expression. Transcriptome analysis showed that AmAChE1 knockdown upregulated protein biosynthesis, cell respiration, and thermogenesis in the head. These findings suggest that AmAChE1 is involved in decreasing neuronal activity, enhancing energy conservation, and potentially extending longevity under stressful conditions via ACh titre regulation.
Title: Lignan-Rich Sesame (Sesamum indicum L.) Cultivar Exhibits In Vitro Anti-Cholinesterase Activity, Anti-Neurotoxicity in Amyloid-beta Induced SH-SY5Y Cells, and Produces an In Vivo Nootropic Effect in Scopolamine-Induced Memory Impaired Mice Kim MY, Kim S, Lee J, Kim JI, Oh E, Kim SW, Lee E, Cho KS, Kim CS, Lee MH Ref: Antioxidants (Basel), 12:, 2023 : PubMed
Alzheimer's disease, a major cause of dementia, is characterized by impaired cholinergic function, increased oxidative stress, and amyloid cascade induction. Sesame lignans have attracted considerable attention owing to their beneficial effects on brain health. This study investigated the neuroprotective potential of lignan-rich sesame cultivars. Among the 10 sesame varieties studied, Milyang 74 (M74) extracts exhibited the highest total lignan content (17.71 mg/g) and in vitro acetylcholinesterase (AChE) inhibitory activity (66.17%, 0.4 mg/mL). M74 extracts were the most effective in improving cell viability and inhibiting reactive oxygen species (ROS) and malondialdehyde (MDA) generation in amyloid-beta(25-35) fragment-treated SH-SY5Y cells. Thus, M74 was used to evaluate the nootropic effects of sesame extracts and oil on scopolamine (2 mg/kg)-induced memory impairment in mice compared to the control cultivar (Goenback). Pretreatment with the M74 extract (250 and 500 mg/kg) and oil (1 and 2 mL/kg) effectively improved memory disorder in mice (demonstrated by the passive avoidance test), inhibited AChE, and enhanced acetylcholine (Ach) levels. Moreover, immunohistochemistry and Western blot results showed that the M74 extract and oil reversed the scopolamine-induced increase in APP, BACE-1, and presenilin expression levels in the amyloid cascade and decreased BDNF and NGF expression levels in neuronal regeneration.
Title: Solvent-free enzymatic synthesis and evaluation of vanillyl propionate as an effective and biocompatible preservative Lee Y, Lee S, Kim S, Lee D, Won K Ref: Bioprocess Biosyst Eng, :, 2023 : PubMed
Preservatives are chemicals added to protect products against microbial spoilage, and thus are indispensable for pharmaceuticals, cosmetics, and foods. Due to growing concerns about human health and environments in conventional chemical preservatives, many companies have been seeking safe and effective alternatives that can be produced through environment-friendly processes. In this work, in order to develop effective and safe preservatives from plants, we attempt solvent-free lipase-catalyzed transesterification of vanillyl alcohol with ethyl propionate for the first time. The reaction product, vanillyl propionate was efficiently obtained in a high yield. Unlike vanillyl alcohol and ethyl propionate, vanillyl propionate showed antimicrobial activity. The minimal inhibitory concentration test showed that it exhibited high and broad antimicrobial activity against all the tested microorganisms (Gram-negative and Gram-positive bacteria, yeasts, and molds), which was overall comparable to that of propyl paraben, which is one of the most effective preservatives. It was also found to have even higher antioxidant capacity and biocompatibility with human cells than propyl paraben. Vanillyl propionate, which is a plant-based preservative produced through a green bioprocess, is expected to be successfully applied to various industries thanks to its high antimicrobial and antioxidant effect, and high biocompatibility.
Title: Targeting Wnt/beta-catenin-mediated upregulation of oncogenic NLGN3 suppresses cancer stem cells in glioblastoma Yun EJ, Kim D, Kim S, Hsieh JT, Baek ST Ref: Cell Death Dis, 14:423, 2023 : PubMed
Glioblastoma (GBM) is the most malignant tumor in brain and is highly resistant to therapy. Clinical evidence suggests increased number of cancer stem cells (CSCs) may contribute to the failure of conventional therapies, but the mechanisms associated with acquisition of CSC properties in GBM are not fully understood. We found that DAB2IP suppresses CSC properties by targeting the synaptic proteins neuroligin 3 (NLGN3) in GBM. Furthermore, we showed that GBM-derived NLGN3 has an oncogenic function by inducing CSC properties within GBM. Moreover, elevated NLGN3 transcription mediated by Wnt/beta-catenin signaling pathway resulted in increased secretion of NLGN3 into the surrounding tumor microenvironment. Both condition media containing NLGN3 and recombinant NLGN3 transformed neighboring cells to CSCs, suggesting NLGN3 as a critical component inducing CSC properties. Furthermore, targeting NLGN3-bearing CSCs using upstream Wnt/beta-catenin inhibitors synergistically enhances the efficacy of conventional treatment. Hence, we unveiled the series of regulatory mechanisms for acquisition of CSC properties in GBM progression by Wnt/beta-catenin-mediated NLGN3. These results may provide a new targeting strategy to improve the therapeutic efficacy of GBM treatments.
SignificanceTocopherols (vitamin E) are plant-synthesized, lipid-soluble antioxidants whose dietary intake, primarily from seed oils, is essential for human health. Tocopherols contain a phytol-derived hydrophobic tail whose in vivo source has been elusive. The most significant genome-wide association signal for Arabidopsis seed tocopherols identified an uncharacterized, seed-specific esterase (VTE7) localized to the chloroplast envelope, where tocopherol synthesis occurs. VTE7 disruption and overexpression had large impacts on tissue tocopherol contents with metabolic phenotypes consistent with release of prenyl alcohols, including phytol, during chlorophyll synthesis, rather than from the bulk degradation of thylakoid chlorophylls as has long been assumed. Understanding the source of phytol for tocopherols will enable breeding and engineering plants for vitamin E biofortification and enhanced stress resilience.
Anti-dementia medications are widely prescribed to patients with Alzheimer's dementia (AD) in South Korea. This study investigated the pattern of medical management in newly diagnosed patients with AD using a standardized data format-the Observational Medical Outcome Partnership Common Data Model from five hospitals. We examined the anti-dementia treatment patterns from datasets that comprise > 5 million patients during 2009-2019. The medication utility information was analyzed with respect to treatment trends and persistence across 11 years. Among the 8653 patients with newly diagnosed AD, donepezil was the most commonly prescribed anti-dementia medication (4218; 48.75%), followed by memantine (1565; 18.09%), rivastigmine (1777; 8.98%), and galantamine (494; 5.71%). The rising prescription trend during observation period was found only with donepezil. The treatment pathways for the three cholinesterase inhibitors combined with N-methyl-D-aspartate receptor antagonist were different according to the drugs (19.6%; donepezil; 28.1%; rivastigmine, and 17.2%; galantamine). A 12-month persistence analysis showed values of approximately 50% for donepezil and memantine and approximately 40% for rivastigmine and galantamine. There were differences in the prescribing pattern and persistence among anti-dementia medications from database using the Observational Medical Outcome Partnership Common Data Model on the Federated E-health Big Data for Evidence Renovation Network platform in Korea.
Title: Bioinformatic Expansion of Borosins Uncovers Trans-Acting Peptide Backbone N-Methyltransferases in Bacteria Cho H, Lee H, Hong K, Chung H, Song I, Lee JS, Kim S Ref: Biochemistry, 61:183, 2022 : PubMed
Backbone N-methylation is one of the prominent peptide modifications that can greatly enhance the pharmacological properties of a peptide. Naturally occurring backbone N-methylated peptides are produced via nonribosomal or ribosomal pathways, the latter of which was only recently identified in the borosin family of ribosomally synthesized and post-translationally modified peptides. Although previous bioinformatic analyses have revealed new putative genes for borosin biosynthesis, the natural scope of structural and biosynthetic diversity of the borosin family has not been thoroughly explored. Here, we report a comprehensive overview of the borosin family of peptide natural products. Using a genome mining approach, we identified more than 1400 new putative biosynthetic gene clusters for borosins and demonstrated that, unlike those previously reported, most of them are found in bacterial genomes and encode a precursor peptide unfused to its cognate methyltransferase enzyme. Biochemical analysis confirmed the backbone N-methylation of the precursor peptide in trans in eight enzyme-precursor pairs and revealed two novel types of enzyme-recognizing sequences in the precursor peptide. This work significantly expands the biosynthetic diversity of borosins and paves the way for the enzymatic production of diverse backbone N-methylated peptides.
Title: 2,4-Diacetylphloroglucinol Reduces Beta-Amyloid Production and Secretion by Regulating ADAM10 and Intracellular Trafficking in Cellular and Animal Models of Alzheimer's Disease Jang BG, Choi B, Kim S, Lee DS, Lee J, Koh YH, Jo SA, Kim JE, Kang TC, Kim MJ Ref: Cells, 11:, 2022 : PubMed
There is currently no effective treatment against Alzheimer's disease (AD), although many strategies have been applied to reduce beta-amyloid (Abeta) levels. Here, we investigated 2,4-diacetylphloroglucinol (DAPG) effects on Abeta levels and mechanisms of action. DAPG was the most effective phloroglucinol derivative for reducing Abeta levels, without being toxic, in various models including HEK293 cells overexpressing Swedish mutant amyloid precursor protein (APP) (293sw), primary astrocytes isolated from APPsw/PS1dE9 transgenic mice, and after intrahippocampal injection of DAPG in APPsw/PS1dE9 transgenic mice. DAPG-mediated Abeta reduction was associated with increased soluble APPalpha (sAPPalpha) levels mediated by a disintegrin and metalloproteinase domain-containing protein 10 (ADAM10) but not ADAM17. ADAM10 inhibition in DAPG-treated cells prevented the effects on sAPPalpha but only partly on intracellular and secreted Abeta. To identify regulators of sAPPalpha and Abeta secretion, various inhibitors of intracellular trafficking were administered with DAPG. Brefeldin A (BFA) reversed DAPG-mediated changes in Abeta secretion in 293sw cells, whereas golgicide A (GCA) and BFA were effective in primary astrocytes, indicating a cell type-specific regulation of the trafficking. Moreover, GCA or BFA effects on sAPPalpha, but not Abeta, levels in primary astrocytes resembled those of ADAM10 inhibition, indicating at least partly independent trafficking pathways for sAPPalpha and Abeta. In conclusion, DAPG might be a promising drug candidate against AD regulating ADAM10 and intracellular trafficking, but optimizing DAPG ability to cross the BBB will be needed.
Title: Molecular and kinetic characterization of two acetylcholinesterases with particular focus on the roles of two amino acid substitutions (Y390N and F392W) in Bemisia tabaci Kim S, Yoon KA, Cho S, Lee SH Ref: Pestic Biochem Physiol, 182:105039, 2022 : PubMed
Two acetylcholinesterases (AChEs) are present in Bemisia tabaci (BtAChE1 and BtAChE2). A conserved AChE mutation conferring organophosphate (OP) resistance (F392W in BtAChE1) is saturated in field populations despite its potential fitness cost, and a highly conserved amino acid residue forming the backdoor of AChE is substituted with a unique amino acid (Y390N in BtAChE1) in B. tabaci. Thus, the roles and relationships of the two amino acid substitutions in the evolutionary adaptation of B. tabaci remain to be elucidated, and little information is available on the catalytic and molecular properties of BtAChE1 and BtAChE2. To determine which AChE is a more relevant target of OPs and carbamates, the molecular and kinetic properties of BtAChE1 and BtAChE2 were investigated. Both BtAChE1 and BtAChE2 were exclusively expressed in head and thorax but not in abdomen, bound to the membrane via GPI anchoring, and present as dimeric forms. Soluble monomeric form was detected only in BtAChE2. The catalytic activity of baculovirus-expressed BtAChE1 was 19.5-fold higher than that of BtAChE2. The inhibition assay revealed that the F392W mutation in BtAChE1 enhanced resistance to OPs. The artificial substitution of N390 (wild form) to Y (putative ancient form) led to reduced catalytic efficiency and increased inhibition by glycoalkaloids, suggesting that the Y390N substitution in BtAChE1 may have been required for Solanaceae host adaptation. BtAChE1 was proven to function as a main catalytic enzyme for ACh hydrolysis, thus being the main target of OPs and carbamates.
Title: Short communication: Screening of proof-of-concept mutations of honey bee acetylcholinesterase 2 conferring resistance to organophosphorus and carbamate insecticides Kim S, Yoon KA, Lee SH Ref: Comparative Biochemistry & Physiology C Toxicol Pharmacol, :109524, 2022 : PubMed
The introduction of pesticide resistance-inducing mutations into target genes would in theory protect honey bees from the hazardous effects of pesticides. In this paper, to screen amino acid substitutions conferring resistance to organophosphorus and carbamate insecticides, honey bee acetylcholinesterase 2 (AmAChE2) variants with several mutations (V260L, A316S, G342A, G342V, F407Y, and G342V/F407Y) were generated and expressed in vitro using a baculovirus system. The inhibition constants of recombinant native and mutated AmAChE2s against six pesticides were measured. As a result, the A316S mutation was shown to induce high resistance without a catalytic efficiency change.
Title: Molecular and kinetic properties of three acetylcholinesterases in the Varroa mite, Varroa destructor Kim S, Yoon KA, Cho S, Lee J, Lim Y, Lee SH Ref: Pestic Biochem Physiol, 188:105277, 2022 : PubMed
The Varroa mite, Varroa destructor, poses one of the most serious threats to honey bees worldwide. Although coumaphos, an anticholinesterase pesticide, is widely used for varroa mite control, little information is available on the properties of Varroa mite acetylcholinesterases (VdAChEs). In this study, three putative VdAChEs were annotated and named VdAChE1, VdAChE2, and VdAChE3. All VdAChEs possessed most of the functionally important signature domains, suggesting that they are catalytically active. Phylogenetic analysis revealed that VdAChE1 was clustered into a clade containing most arthropod AChE1s, whereas VdAChE2 and VdAChE3 formed a unique clade with other arachnid AChEs. VdAChE1 was determined to be membrane-anchored, but both VdAChE2 and VdAChE3 are soluble, as judged by electrophoresis in conjunction with western blotting. Tissue-specific transcription profiling revealed that VdAChE1 was most predominantly expressed in the synganglion. In contrast, VdAChE2 was most predominantly expressed in the legs and cuticle. VdAChE3 showed negligible expression levels in all the tissues examined. In a kinetic analysis using recombinant VdAChEs, VdAChE1 exhibited the highest catalytic efficiency, followed by VdAChE2 and VdAChE3. Inhibition experiments revealed that VdAChE1 was most sensitive to all tested inhibitors. Taken together, VdAChE1 appears to be the major synaptic enzyme with a more toxicological relevance, whereas VdAChE2 is involved in other noncatalytic functions, including chemical defense against xenobiotics. Current findings contribute to a more detailed understanding of the evolutionary and functional traits of VdAChEs and to the design of novel anticholinesterase varroacides.
We developed a proximity photo-crosslinking method (Spotlight) with a 4-azido-N-ethyl-1,8-naphthalimide (AzNP) moiety that can be converted to reactive aryl nitrene species using ambient blue light-emitting diode light. Using an AzNP-conjugated HaloTag ligand (VL1), blue light-induced photo-crosslinked products of various HaloTag-conjugated proteins of interest were detected in subcellular spaces in live cells. Chemical or heat stress-induced dynamic changes in the proteome were also detected, and photo-crosslinking in the mouse brain tissue was enabled. Using Spotlight, we further identified the host interactome of SARS-CoV-2 nucleocapsid (N) protein, which is essential for viral genome assembly. Mass analysis of the VL1-crosslinked product of N-HaloTag in HEK293T cells showed that RNA-binding proteins in stress granules were exclusively enriched in the cross-linked samples. These results tell that our method can reveal the interactome of protein of interest within a short distance in live cells.
Title: Insecticide resistance in pepper greenhouse populations of Aphis gossypii (Hemiptera: Aphididae) in Korea Nam HY, Kim S, Lee SH, Lee JH, Kim J Ref: Pestic Biochem Physiol, 182:105033, 2022 : PubMed
The cotton aphid or melon aphid, Aphis gossypii Glover (Hemiptera: Aphididae), is a polyphagous insect pest with a wide host range. Two distinct genetic clusters were found in A. gossypii populations in Korea. To determine whether the division of the genetic clusters was driven by insecticide selection pressure, the frequencies of insecticide resistance-associated mutations on three representative insecticide target genes [i.e., nicotinic acetylcholine receptor gene (nAChR), voltage-gated sodium channel gene (vgsc), and acetylcholinesterase 1 gene (ace-1)] were predicted in A. gossypii populations with known genetic structures. Most populations revealed heterozygosity-resistant alleles for the nAChR R81T and vgsc M918L mutations, but homozygous-resistant alleles for the ace-1 S431F mutation. However, assessment of the three mutation frequencies revealed no apparent correlation between the genetic structures and the resistance profiles. The regression analysis revealed no correlation between the genetic cluster ratios and resistance allele frequencies (R81T, S431F, and M918L). We used three insecticides that are commonly used in greenhouses: imidacloprid (neonicotinoid), acephate (organophosphate), and esfenvalerate (pyrethroid), to test resistance and susceptibility in A. gossypii populations. The bioassay results revealed that the BS_19 (Busan) and JE_19 (Jeongeup) populations were resistant to imidacloprid and acephate, the HS_19 (Honseong) population was resistant to acephate and esfenvalerate, and susceptible lab strains only exhibited resistance to acephate. The bioassay results were correlated with mutation frequency, but no correlation was detected among genetic clusters. These results suggest that the distinct genetic structure observed in the Korean populations of A. gossypii is not likely influenced by insecticide resistance traits, but rather by other factors.
Title: Structural and functional characterization of an auxiliary domain-containing PET hydrolase from Burkholderiales bacterium Sagong HY, Kim S, Lee D, Hong H, Lee SH, Seo H, Kim KJ Ref: J Hazard Mater, 429:128267, 2022 : PubMed
Biodegradation of polyethylene terephthalate (PET) is one of fundamental ways to solve plastic pollution. As various microbial hydrolases have an extra domain unlike PETase from Ideonella sakaiensis (IsPETase), research on the role of these extra domain in PET hydrolysis is crucial for the identification and selection of a novel PET hydrolase. Here, we report that a PET hydrolase from Burkholderiales bacterium RIFCSPLOWO2_02_FULL_57_36 (BbPETase) with an additional N-terminal domain (BbPETase(AND)) shows a similar hydrolysis activity toward microcrystalline PET and a higher thermal stability than IsPETase. Based on detailed structural comparisons between BbPETase and IsPETase, we generated the BbPETase(S335N/T338I/M363I/N365G) variant with an enhanced PET-degrading activity and thermal stability. We further revealed that BbPETase(AND) contributes to the thermal stability of the enzyme through close contact with the core domain, but the domain might hinder the adhesion of enzyme to PET substrate. We suggest that BbPETase is an enzyme in the evolution of efficient PET degradation and molecular insight into a novel PET hydrolase provides a novel strategy for the development of biodegradation of PET.
Title: Lipase-catalyzed production of pyridoxine monolaurate in solvent-free bioreactor system Yu H, Kim S, Chang PS Ref: Food Chem, 399:133949, 2022 : PubMed
This study demonstrated that solvent-free gas bubbling system enhanced production efficiency of pyridoxine monolaurate in the esterification catalyzed by immobilized Candida antarctica lipase B (Lipozyme 435). Volumetric productivity in solvent-free gas bubbling system (41.24 mmol/L/h) was 3.7 and 2.1-fold higher than those in conventional organic solvent system (11.10 mmol/L/h) and solvent-free system (19.86 mmol/L/h) using magnetic stirring, respectively. Among the three bioreactor systems, solvent-free gas bubbling system provided the best reusability of the lipase retaining 94.45 % of initial activity for six batch reactions. In the bioreactor system, 5-O-lauroyl-pyridoxine was regioselectively produced with maximum production of 371.17 mmol/L at 70 degreesC and 0.10 of substrate molar ratio ([pyridoxine]/[lauric acid]) for 9 h. Pyridoxine monolaurate exhibited interfacial activity at oil-water interfaces, suggesting it had emulsifying properties. Pyridoxine monolaurate is expected to be applied as a multi-functional emulsifier with nutritional values to replace both small molecule emulsifiers and pyridoxine hydrochloride in fortified beverages.
Title: Subcutaneously Injectable Hyaluronic Acid Hydrogel for Sustained Release of Donepezil with Reduced Initial Burst Release: Effect of Hybridization of Microstructured Lipid Carriers and Albumin Kang NW, Yoon SY, Kim S, Yu NY, Park JH, Lee JY, Cho HJ, Kim DD Ref: Pharmaceutics, 13:, 2021 : PubMed
The daily oral administration of acetylcholinesterase (AChE) inhibitors for Alzheimer's disease features low patient compliance and can lead to low efficacy or high toxicity owing to irregular intake. Herein, we developed a subcutaneously injectable hyaluronic acid hydrogel (MLC/HSA hydrogel) hybridized with microstructured lipid carriers (MLCs) and human serum albumin (HSA) for the sustained release of donepezil (DNP) with reduced initial burst release. The lipid carrier was designed to have a microsized mean diameter (32.6 +/- 12.8 microm) to be well-localized in the hydrogel. The hybridization of MLCs and HSA enhanced the structural integrity of the HA hydrogel, as demonstrated by the measurements of storage modulus (G'), loss modulus (G''), and viscosity. In the pharmacokinetic study, subcutaneous administration of MLC/HSA hydrogel in rats prolonged the release of DNP for up to seven days and reduced the initial plasma concentration, where the C(max) value was 0.3-fold lower than that of the control hydrogel without a significant change in the AUC(last) value. Histological analyses of the hydrogels supported their biocompatibility for subcutaneous injection. These results suggest that a new hybrid MLC/HSA hydrogel could be promising as a subcutaneously injectable controlled drug delivery system for the treatment of Alzheimer's disease.
Title: Impaired formation of high-order gephyrin oligomers underlies gephyrin dysfunction-associated pathologies Kim S, Kang M, Park D, Lee AR, Betz H, Ko J, Chang I, Um JW Ref: iScience, 24:102037, 2021 : PubMed
Gephyrin is critical for the structure, function, and plasticity of inhibitory synapses. Gephyrin mutations have been linked to various neurological disorders; however, systematic analyses of the functional consequences of these mutations are lacking. Here, we performed molecular dynamics simulations of gephyrin to predict how six reported point mutations might change the structural stability and/or function of gephyrin. Additional in silico analyses revealed that the A91T and G375D mutations reduce the binding free energy of gephyrin oligomer formation. Gephyrin A91T and G375D displayed altered clustering patterns in COS-7 cells and nullified the inhibitory synapse-promoting effect of gephyrin in cultured neurons. However, only the G375D mutation reduced gephyrin interaction with GABA(A) receptors and neuroligin-2 in mouse brain; it also failed to normalize deficits in GABAergic synapse maintenance and neuronal hyperactivity observed in hippocampal dentate gyrus-specific gephyrin-deficient mice. Our results provide insights into biochemical, cell-biological, and network-activity effects of the pathogenic G375D mutation.
Donepezil is a reversible acetylcholinesterase inhibitor that is currently the most commonly prescribed drug for the treatment of Alzheimer's disease. In general, donepezil is known as a safe and well-tolerated drug, and it was not associated with liver abnormalities in several clinical trials. However, rare cases of drug-related liver toxicity have been reported since it has become commercially available. Few studies have investigated the metabolic profile of donepezil, and the mechanism of liver damage caused by donepezil has not been elucidated. In this study, the in vitro metabolism of donepezil was investigated using liquid chromatography-tandem mass spectrometry based on a non-targeted metabolomics approach. To identify metabolites, the data were subjected to multivariate data analysis and molecular networking. A total of 21 donepezil metabolites (17 in human liver microsomes, 21 in mice liver microsomes, and 17 in rat liver microsomes) were detected including 14 newly identified metabolites. One potential reactive metabolite was identified in rat liver microsomal incubation samples. Metabolites were formed through four major metabolic pathways: (1) O-demethylation, (2) hydroxylation, (3) N-oxidation, and (4) N-debenzylation. This study indicates that a non-targeted metabolomics approach combined with molecular networking is a reliable tool to identify and detect unknown drug metabolites.
PubChem (https://pubchem.ncbi.nlm.nih.gov) is a popular chemical information resource that serves the scientific community as well as the general public, with millions of unique users per month. In the past two years, PubChem made substantial improvements. Data from more than 100 new data sources were added to PubChem, including chemical-literature links from Thieme Chemistry, chemical and physical property links from SpringerMaterials, and patent links from the World Intellectual Properties Organization (WIPO). PubChem's homepage and individual record pages were updated to help users find desired information faster. This update involved a data model change for the data objects used by these pages as well as by programmatic users. Several new services were introduced, including the PubChem Periodic Table and Element pages, Pathway pages, and Knowledge panels. Additionally, in response to the coronavirus disease 2019 (COVID-19) outbreak, PubChem created a special data collection that contains PubChem data related to COVID-19 and the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).
Most nanoparticles show much higher uptake in mononuclear phagocyte system (MPS) organs than in tumors, which has been a long-lasting dilemma in nanomedicine. Here, we report an imaging strategy that selectively decreases MPS organ uptakes by utilizing the differential esterase activity in tumors and other organs. When an esterase-labile radiotracer loaded liposome was injected into the body, radioactivity was rapidly excreted from the liver and spleen after breakage of the ester bond by esterase. However, the lipophilic radiotracer delivered to the tumor remained in the tumor with minimal bond cleavage. The underlying mechanism was fully characterized in vitro and in vivo in colon tumor models. As a proof of concept, the liposomal radiotracer was further optimized for the early detection of pancreatic cancer. The folate-coated liposomal radiotracer showed highly selective tumor uptake. At 4 h postinjection, a pancreatic tumor a few millimeters in size was unambiguously visualized in orthotopic tumor models by PET imaging. At 24 h, an exceptionally high tumor-to-background ratio was achieved, enabling the visualization of tumors alone with minimal background noise. More than 9% of the total radioactivity was found in the tumor. Utilizing our imaging strategy, various tumor imaging agents can be developed for sensitive detection with ultrahigh contrast.
Title: Insecticide resistance trait may contribute to genetic cluster change in Bemisia tabaci MED (Hemiptera: Aleyrodidae) as a potential driving force Park Y, Kim S, Lee SH, Lee JH Ref: Pest Manag Sci, :, 2021 : PubMed
BACKGROUND: Previously, we had reported that the majority of the Bemisia tabaci Mediterranean (MED) populations converged from two dominant genetic clusters (cluster 1 and 2) to one (cluster 2) during one year in greenhouse tomatoes in Korea. To find possible mechanisms for this phenomenon, we investigated the concurrent changes in resistance traits of the two clusters for three insecticide classes (organophosphate, pyrethroid, and neonicotinoid). RESULTS: Since the resistance mutation frequencies in regional samples were either high (i.e., the voltage-sensitive sodium channel L925I/T929V mutations and the F392 acetylcholinesterase 1 mutation) or zero (the nicotinic acetylcholine receptor R81T mutation), no meaningful correlation between the resistance allele frequency and genetic cluster was deduced. However, the actual resistance levels to all three insecticide classes were significantly higher in cluster 2 than those in cluster 1, suggesting that cluster 2 has a higher resistance potential. Furthermore, thiamethoxam treatment to the mixed population of clusters 1 and 2 over three generations exhibited a strong tendency of population change from cluster 1 to cluster 2. CONCLUSION: Our results demonstrated that the insecticide resistance trait is one of the driving forces for rapid genetic cluster change in the B. tabaci MED populations.
Title: Change in cognitive function according to cholinesterase inhibitor use and amyloid PET positivity in patients with mild cognitive impairment Pyun JM, Ryoo N, Park YH, Kim S Ref: Alzheimers Res Ther, 13:10, 2021 : PubMed
BACKGROUND: Cholinesterase inhibitors (ChEIs) are an FDA-approved symptomatic treatment for patients with Alzheimer's disease (AD). Its efficacy in patients with mild cognitive impairment (MCI), however, is controversial. Nonetheless, ChEIs have often been used in patients with MCI. From the perspective that ChEIs were developed based on the pathomechanism of AD, the effect of ChEIs in MCI patients could be different depending on the amyloid burden. In this retrospective observational study, we aimed to investigate the influence of ChEIs and amyloid burden on cognitive change for 1 year in patients with MCI. METHODS: We included 111 patients with MCI with a Clinical Dementia Rating (CDR) score of 0.5, a 1-year follow-up cognitive assessment, and amyloid positron emission tomography (PET) performed within 6 months before or after the baseline cognitive assessment (73 ChEI users and 38 ChEI non-users) from the Neurocognitive Behavior Center of Seoul National University Bundang Hospital. Additionally, those who had a positive amyloid PET scan more than 6 months before the baseline cognitive assessment and those who had a negative amyloid PET scan more than 6 months after the 1-year follow-up cognitive assessment were also included. Among the total 111 patients, 25 ChEI users and 25 ChEI non-users were matched by baseline Mini-Mental State Examination (MMSE) score, age, educational level, CDR Sum of Boxes, and amyloid PET positivity using propensity score matching. Multiple linear regression analysis was performed to assess the influence of ChEI use and amyloid PET positivity on cognitive change for 1 year. Univariate and multivariate logistic regression analyses were performed to evaluate the association between ChEI use and disease progression to CDR 1 at the 1-year follow-up visit. RESULTS: ChEI use or non-use was not associated with cognitive change for 1 year. Amyloid PET positivity or negativity did not change this non-association. Furthermore, progression to CDR 1 was related to low baseline MMSE score (OR 0.606, CI 0.381-0.873), but not with ChEI use or non-use, and not with amyloid PET result. CONCLUSION: ChEI use or non-use was not related to cognitive change at a 1-year follow-up visit in patients with or without amyloid burden. In addition, ChEI use or non-use could not predict disease progression to CDR 1 at 1-year follow-up visit.
Exosomes, which are small extracellular vesicles produced from various cell types, contain a variety of molecular constituents, such as proteins, lipids, and RNA. Recently, exosomal biomarkers have been investigated to probe the understanding and diagnosis of neurodegenerative disorders. Previous reports have demonstrated increased exosomal alpha-synuclein (alpha-syn) in patients with Parkinson's disease (PD) in comparison to healthy controls (HC). Interestingly, the cholinergic loss was revealed in the central and peripheral nervous systems in histopathology and molecular neuroimaging. Thereby, we simultaneously examined acetylcholinesterase (AChE) with alpha-syn as exosomal markers. Exosomes were isolated from the plasma of 34 FP-CIT PET proven patients with PD and 29 HC. Exosomal alpha-syn and AChE activity were quantified andthe relationship with clinical parameters was analyzed. Remarkably, exosomal AChE activity was significantly decreased in PD compared to HC (P = 0.002). Moreover, exosomal AChE activity in PD revealed a strong negative correlation with disease severity, including H&Y (P = 0.007) and UPDRS part III (P = 0.047) scores. By contrast, no significant difference in exosomal alpha-syn concentration was observed between groups. These results support the occurrence of cholinergic dysfunction in PD, and they could be implicated with disease progression, especially motor deficits. Exosomal AChE activity with advanced exosome isolation techniques may be a reliable biomarker for the early diagnosis and prognosis of PD.
BACKGROUND AND PURPOSE: Poststroke cognitive impairment (PSCI) is common, but the impact of beta-amyloid (Abeta) on PSCI is uncertain. The proposed study will investigate amyloid pathology in participants with PSCI and how differently their cognition progress according to the amyloid pathology. METHODS: This multicenter study was designed to be prospective and observational based on a projected cohort size of 196 participants with either newly developed cognitive impairment, or rapidly aggravated CI, within 3 months after acute cerebral infarction. They will undergo 18F-flutemetamol positron emission tomography at baseline and will be categorized as either amyloid-positive (A+) or amyloid-negative (A-) by visual rating. The primary outcome measures will be based on Korean Mini-Mental State Examination changes (baseline to 12months) between the A+ and A- groups. The secondary outcome measures will be the dementia-conversion rate and changes in the Korean version of the Montreal Cognitive Assessment (baseline to 12months) between the A+ and A- groups. CONCLUSIONS: This study will provide a broadened perspective on the impact of Abeta on the cause and outcomes of PSCI in clinical practice. Identifying amyloid pathology in patients with PSCI will help select patients who need more focused treatments such as acetylcholinesterase inhibitors. TRIAL REGISTRATION: Clinical Research Information Service identifier: KCT0005086.
ETHNOPHARMACOLOGICAL RELEVANCE: Dracocephalum moldavica (Moldavian balm) has been traditionally used for the treatment of intellectual disabilities, migraines and cardiovascular problems in East Asia. Recent scientific studies have demonstrated the usefulness of this plant to treat neurodegenerative disorders, including Alzheimer's disease. AIM OF THE STUDY: This study aimed to investigate the effects of the ethanolic extract of D. moldavica leaves (EEDM) on scopolamine-induced cognitive impairment in mice and the underlying mechanisms of action. MATERIALS AND METHODS: The behavioral effects of EEDM were examined using the step-through passive avoidance and Morris water maze tasks. To elucidate the underlying mechanism, we tested whether EEDM affects acetylcholinesterase activity and the expression of memory-related signaling molecules including extracellular signal-regulated kinase (ERK) and cAMP response element-binding protein (CREB) in the hippocampus. RESULTS: EEDM (25, 50 or 100mg/kg) significantly ameliorated the scopolamine-induced step-through latency reduction in the passive avoidance task in mice. In the Morris water maze task, EEDM (50mg/kg) significantly attenuated scopolamine-induced memory impairment. Furthermore, the administration of EEDM increased the phosphorylation levels of ERK and CREB in the hippocampus but did not alter acetylcholinesterase activity. CONCLUSIONS: These findings suggest that EEDM significantly attenuates scopolamine-induced memory impairment in mice and may be a promising therapeutic agent for improving memory impairment.
Middle East respiratory syndrome (MERS) is a respiratory disease caused by a coronavirus (MERS-CoV). Since its emergence in 2012, nosocomial amplifications have led to its high epidemic potential and mortality rate of 34.5 %. To date, there is an unmet need for vaccines and specific therapeutics for this disease. Available treatments are either supportive medications in use for other diseases or those lacking specificity requiring higher doses. The viral infection mode is initiated by the attachment of the viral Spike glycoprotein to the human Dipeptidyl Peptidase IV (DPP4). Our attempts to screen antivirals against MERS led us to identify montelukast sodium hydrate (MSH), an FDA-approved anti-asthma drug, as an agent attenuating MERS-CoV infection. We showed that MSH directly binds to MERS-CoV-Receptor-Binding Domain (RBD) and inhibits its molecular interaction with DPP4 in a dose-dependent manner. Our cell-based inhibition assays using MERS pseudovirions demonstrated that viral infection was significantly inhibited by MSH and was further validated using infectious MERS-CoV culture. Thus, we propose MSH as a potential candidate for therapeutic developments against MERS-CoV infections.
Title: Neuroprotective Effect of Cudrania tricuspidata Fruit Extracts on Scopolamine-Induced Learning and Memory Impairment Jee SC, Lee KM, Kim M, Lee YJ, Kim S, Park JO, Sung JS Ref: Int J Mol Sci, 21:, 2020 : PubMed
Cudrania tricuspidata has diverse biological activities, such as antioxidant, anti-inflammatory, anticancer, and neuroprotective effects. This study investigated the protective effects of C. tricuspidata fruit extracts (CTFE) against scopolamine (SCO)-induced neuron impairment. The neuroprotective effects of CTFE on SCO-induced memory dysfunction were confirmed in mice using the Barnes maze test. The results showed that co-treatment of SCO and CTFE increased the stay time in the target zone compared with SCO treatment alone. Similarly, the results obtained by the fear conditioning test revealed that SCO-CTFE co-treatment induced the freezing action time under both the contextual fear condition and the cued fear condition compared with SCO treatment alone. Moreover, we showed that CTFE reduced the SCO-induced acetylcholinesterase (AChE) activity, thereby increasing the acetylcholine concentration in mice hippocampal tissues. Consistent with the improvement of memory and recognition function in vivo, our in vitro results showed that CTFE induced cAMP response element binding protein (CREB) and extracellular regulated kinase 1/2 (ERK1/2) activity in PC12 cells and reduced SCO-induced AChE activity. In addition, the microarray results of the hippocampal tissue support our data showing that CTFE affects gene expressions associated with neurogenesis and neuronal cell differentiation markers such as spp1 and klk6. Overall, CTFE exerts a neuroprotective effect via regulation of the CREB and ERK1/2 signaling pathways and could be a therapeutic candidate for neurodegenerative diseases.
Title: Memory-Enhancing Effects of Mangosteen Pericarp Water Extract through Antioxidative Neuroprotection and Anti-Apoptotic Action Oh Y, Do HTT, Kim S, Kim YM, Chin YW, Cho J Ref: Antioxidants (Basel), 10:, 2020 : PubMed
Mangosteen has long been utilized as a traditional medicine in Southeast Asia. Diverse extracts of mangosteen pericarp and its bioactive xanthones exhibit various bioactivities. However, the pharmacological potential of mangosteen pericarp water extract (MPW) has not been reported yet. This study used primary cultured rat cortical cells to investigate the effect of MPW on neurotoxicity. We found that MPW inhibited neurotoxicity and production of reactive oxygen species triggered by Abeta((25-35)) or excitatory amino acids. MPW inhibited caspase 3 activation and DNA fragmentation in Abeta((25-35))- or N-methyl-D-aspartate-treated cells, suggesting an anti-apoptotic action. Additionally, MPW reduced lipid peroxidation and scavenged 1,1-diphenyl-2-picrylhydrazyl radicals, assuring its antioxidant property. Furthermore, MPW suppressed beta-secretase and acetylcholinesterase activities. These findings prompted us to evaluate its effect on memory dysfunction in scopolamine-treated mice using Morris water maze test. Oral administration of MPW at the dosage of 50, 100, or 300 mg/kg for four days significantly decreased the latency time to find the platform and markedly increased the swimming time in the target quadrant. Taken together, our results suggest that MPW exerts memory-enhancing effect through antioxidative neuroprotection and anti-apoptotic action. Accordingly, MPW may have a potential to prevent or treat memory impairment associated with Alzheimer's disease.
Title: Biomonitoring the effects of urban-stream waters on the health status of pale chub (Zacco platypus): A comparative analysis of biological indexes and biomarker levels Park CB, Kim GE, Kim DW, Kim S, Yeom DH Ref: Ecotoxicology & Environmental Safety, 208:111452, 2020 : PubMed
The objective of this study was to biomonitor the effects of potential environmental pollutants in urban-stream waters, on fish health. Pale chub (Zacco platypus), a dominant species in the Korea urban stream waters, was chosen and biomonitoring indicators for the different spatial characteristics were tailored in an urban watershed. Biological responses including biotic-somatic index as well as gonadal development phase and plasma steroids levels, and the biochemical responses, ethoxyresorufin-o-deethylase (EROD) and acetylcholinesterase (AChE) activities, were measured. No significant difference was observed in the length-weight relationship between the up-stream waters and the down-stream waters. However, changes in the gonad-somatic index (GSI) levels, plasma 17beta-estradiol (E2) levels, and mature oocyte frequencies in the female fish collected during the spawning season were observed in the down-stream waters at each monitoring site. Moreover, intersex condition (testis-ova) in the male fish in down-stream waters was recorded, even if it was just one fish. Although no significant difference was observed in the EROD and AChE activities between the up-stream waters and the down-stream waters, changes in the reproductive biomarker levels, including the GSI levels, plasma E2 levels, and gonadal maturation, lead to variable biomonitoring endpoints between the spatial different sites. These results imply that exposure to the down-stream waters can cause reproductive impairment in wild Z. platypus, individual variability in the biological responses further indicate the reproductive health was affected more by the down-stream waters than the up-stream waters. The finding from this study can provide the biomonitoring endpoint on the wild fish health in urban watershed that is crucial to the early risk assessment of its biological impacts. More multi-biomarkers studies reflecting the variation in the biological organization of wild fish and, therefore, the effects of urban-stream waters in the fish health are warranted.
Monohydroxyethyl terephthalate (MHET) hydrolase (MHETase) is an enzyme known to be involved in the final degradation step of poly(ethylene terephthalate) (PET) by hydrolyzing MHET into terephthalic acid and ethylene glycol in Ideonella sakaiensis. Here, we report the extracellular production of MHETase in an active form with a proper folding. Based on the structural observations and biochemical experiments, we reveal that MHETase also functions as exo-PETase by hydrolyzing the synthesized PET pentamer. We further present that MHETase has a hydrolysis activity against the termini-generated PET film, demonstrating the exo-PETase function of the enzyme. We also develop a MHETase R411K/S416A/F424I variant with a higher BHET activity, and the variant exhibits an enhanced degradation activity against the PET film. Based on these results, we propose that MHETase plays several roles in the biodegradation of PET using the BHETase and exo-PETase activities as well as the MHET hydrolysis function
Acetylcholinesterase (AChE) activity level can be used as a diagnostic marker for anticholinesterase pesticide poisoning. In this study, we aimed to establish a baseline level of normal brain AChE activity in wild birds. AChE activity was measured in the brains of 87dead wild birds (26 species). The level of AChE activity ranged from 6.40 to 15.9 micromol/min/g of brain tissue in normal wild birds. However, the brain tissue AChE activity level in wild birds exposed to organophosphate (OP) pesticide was 48.0%-96.3% of that in the normal birds. These results may serve as reference values to facilitate routine diagnosis and monitoring of OP-poisoned wild birds.
Title: Identification of Catalposide Metabolites in Human Liver and Intestinal Preparations and Characterization of the Relevant Sulfotransferase, UDP-glucuronosyltransferase, and Carboxylesterase Enzymes Hwang DK, Kim JH, Shin Y, Choi WG, Kim S, Cho YY, Lee JY, Kang HC, Lee HS Ref: Pharmaceutics, 11:, 2019 : PubMed
Catalposide, an active component of Veronica species such as Catalpa ovata and Pseudolysimachion lingifolium, exhibits anti-inflammatory, antinociceptic, anti-oxidant, hepatoprotective, and cytostatic activities. We characterized the in vitro metabolic pathways of catalposide to predict its pharmacokinetics. Catalposide was metabolized to catalposide sulfate (M1), 4-hydroxybenzoic acid (M2), 4-hydroxybenzoic acid glucuronide (M3), and catalposide glucuronide (M4) by human hepatocytes, liver S9 fractions, and intestinal microsomes. M1 formation from catalposide was catalyzed by sulfotransferases (SULTs) 1C4, SULT1A1*1, SULT1A1*2, and SULT1E1. Catalposide glucuronidation to M4 was catalyzed by gastrointestine-specific UDP-glucuronosyltransferases (UGTs) 1A8 and UGT1A10; M4 was not detected after incubation of catalposide with human liver preparations. Hydrolysis of catalposide to M2 was catalyzed by carboxylesterases (CESs) 1 and 2, and M2 was further metabolized to M3 by UGT1A6 and UGT1A9 enzymes. Catalposide was also metabolized in extrahepatic tissues; genetic polymorphisms of the carboxylesterase (CES), UDP-glucuronosyltransferase (UGT), and sulfotransferase (SULT) enzymes responsible for catalposide metabolism may cause inter-individual variability in terms of catalposide pharmacokinetics.
Title: Differential expression of acetylcholinesterase 1 in response to various stress factors in honey bee workers Kim S, Kim K, Lee JH, Han SH, Lee SH Ref: Sci Rep, 9:10342, 2019 : PubMed
The honey bee acetylcholinesterase 1 (AmAChE1) has been suggested to be related to stress response as judged from its elevated expression level under brood rearing-suppressed conditions. To further investigate the involvement of AmAChE1 expression in the stress response and its physiological functions, we analyzed altered expression profiles of AmAChE1 induced by diverse stress factors. In addition, transcription profiles of several heat shock protein (Hsp) genes (hsps) and the vitellogenin (Vg) gene (vg) known as general stress markers were investigated as positive references. Among the tested stress conditions, AmAChE1 expression was induced under the brood rearing-suppressed, crowding and heat shock conditions. The hsps, particularly hsp70 and hsp90, responded to seven of nine stress conditions tested, confirming that hsp expression profiles can serve as a general stress marker. Taken together, AmAChE1 expression is not suitable for using as a stress marker due to its limited response. Nevertheless, AmAChE1 expression appears to be connected, at least in part, to heat shock response and other pathways. Considering that AmAChE1 likely regulates the ACh titer particularly in non-neuronal tissues, thereby modulating the signal cascades mediated by mAChR, the AmAChE1 expression profile under different conditions likely provides important information on its physiological roles in honey bees.
Monoamine oxidase-B (MAO-B) has recently emerged as a potential therapeutic target for Alzheimer's disease (AD) because of its association with aberrant gamma-aminobutyric acid (GABA) production in reactive astrocytes. Although short-term treatment with irreversible MAO-B inhibitors, such as selegiline, improves cognitive deficits in AD patients, long-term treatments have shown disappointing results. We show that prolonged treatment with selegiline fails to reduce aberrant astrocytic GABA levels and rescue memory impairment in APP/PS1 mice, an animal model of AD, because of increased activity in compensatory genes for a GABA-synthesizing enzyme, diamine oxidase (DAO). We have developed a potent, highly selective, and reversible MAO-B inhibitor, KDS2010 (IC(50) = 7.6 nM; 12,500-fold selectivity over MAO-A), which overcomes the disadvantages of the irreversible MAO-B inhibitor. Long-term treatment with KDS2010 does not induce compensatory mechanisms, thereby significantly attenuating increased astrocytic GABA levels and astrogliosis, enhancing synaptic transmission, and rescuing learning and memory impairments in APP/PS1 mice.
Title: Production of extracellular PETase from Ideonella sakaiensis using sec-dependent signal peptides in E. coli Seo H, Kim S, Son HF, Sagong HY, Joo S, Kim KJ Ref: Biochemical & Biophysical Research Communications, 508:250, 2019 : PubMed
Poly(ethylene terephthalate) (PET) is the most commonly used polyester polymer resin in fabrics and storage materials, and its accumulation in the environment is a global problem. The ability of PET hydrolase from Ideonella sakaiensis 201-F6 (IsPETase) to degrade PET at moderate temperatures has been studied extensively. However, due to its low structural stability and solubility, it is difficult to apply standard laboratory-level IsPETase expression and purification procedures in industry. To overcome this difficulty, the expression of IsPETase can be improved by using a secretion system. This is the first report on the production of an extracellular IsPETase, active against PET film, using Sec-dependent translocation signal peptides from E. coli. In this work, we tested the effects of fusions of the Sec-dependent and SRP-dependent signal peptides from E. coli secretory proteins into IsPETase, and successfully produced the extracellular enzyme using pET22b-SPMalE:IsPETase and pET22b-SPLamB:IsPETase expression systems. We also confirmed that the secreted IsPETase has PET-degradation activity. The work will be used for development of a new E. coli strain capable of degrading and assimilating PET in its culture medium.
Background: This study evaluated whether baseline results of the Timed Up and Go (TUG) test is associated with future dementia occurrence. Methods: Using the Korean National Health Insurance Service-National Health Screening Cohort database, we identified 49,283 subjects without a dementia diagnosis who participated in the National Screening Program for Transitional Ages at 66 years of age during 2007-2012. Gait impairment was defined as taking longer than 10 seconds to perform the TUG test. Dementia occurrence was defined by the first prescription for acetylcholinesterase inhibitors or N-Methyl-D-Aspartate receptor antagonist with an International Classification of Diseases 10th Revision (ICD-10) code for dementia (F00, F01, F02, F03, G30, F051, or G311) during 2007-2013. Cox proportional hazard regression models were used to assess the hazard ratios for dementia occurrence according to baseline TUG test results. Results: Mean follow-up period was 3.8 years. Incidence rates of dementia were 4.6 and 6.8 cases per 1,000 person-years in the normal and impaired TUG groups, respectively. The impaired TUG group showed a higher risk of total dementia incidence (adjusted hazard ratio [aHR], 1.34; 95% confidence interval [95% CI], 1.14-1.57). Subtype analysis showed that the impaired TUG group had a higher risk of Alzheimer's disease (aHR, 1.26; 95% CI, 1.06-1.51) and vascular dementia (aHR, 1.65; 95% CI, 1.19-2.30). Conclusions: The TUG test result was associated with future dementia occurrence. More vigilant follow-up and early intervention to prevent dementia would benefit elderly people with impaired TUG test result.
BACKGROUND: Transposable elements are major evolutionary forces which can cause new genome structure and species diversification. The role of transposable elements in the expansion of nucleotide-binding and leucine-rich-repeat proteins (NLRs), the major disease-resistance gene families, has been unexplored in plants. RESULTS: We report two high-quality de novo genomes (Capsicum baccatum and C. chinense) and an improved reference genome (C. annuum) for peppers. Dynamic genome rearrangements involving translocations among chromosomes 3, 5, and 9 were detected in comparison between C. baccatum and the two other peppers. The amplification of athila LTR-retrotransposons, members of the gypsy superfamily, led to genome expansion in C. baccatum. In-depth genome-wide comparison of genes and repeats unveiled that the copy numbers of NLRs were greatly increased by LTR-retrotransposon-mediated retroduplication. Moreover, retroduplicated NLRs are abundant across the angiosperms and, in most cases, are lineage-specific. CONCLUSIONS: Our study reveals that retroduplication has played key roles for the massive emergence of NLR genes including functional disease-resistance genes in pepper plants.
A novel microbial esterase, EaEST, from a psychrophilic bacterium Exiguobacterium antarcticum B7, was identified and characterized. To our knowledge, this is the first report describing structural analysis and biochemical characterization of an esterase isolated from the genus Exiguobacterium. Crystal structure of EaEST, determined at a resolution of 1.9 A, showed that the enzyme has a canonical alpha/beta hydrolase fold with an alpha-helical cap domain and a catalytic triad consisting of Ser96, Asp220, and His248. Interestingly, the active site of the structure of EaEST is occupied by a peracetate molecule, which is the product of perhydrolysis of acetate. This result suggests that EaEST may have perhydrolase activity. The activity assay showed that EaEST has significant perhydrolase and esterase activity with respect to short-chain p-nitrophenyl esters (<=C8), naphthyl derivatives, phenyl acetate, and glyceryl tributyrate. However, the S96A single mutant had low esterase and perhydrolase activity. Moreover, the L27A mutant showed low levels of protein expression and solubility as well as preference for different substrates. On conducting an enantioselectivity analysis using R- and S-methyl-3-hydroxy-2-methylpropionate, a preference for R-enantiomers was observed. Surprisingly, immobilized EaEST was found to not only retain 200% of its initial activity after incubation for 1 h at 80 degrees C, but also retained more than 60% of its initial activity after 20 cycles of reutilization. This research will serve as basis for future engineering of this esterase for biotechnological and industrial applications.
BACKGROUND AND OBJECTIVE: Studies investigating the impact of white matter hyperintensities (WMHs) on the response of acetylcholinesterase inhibitors in patients with Alzheimer's disease (AD) have presented inconsistent results. We aimed to compare the effects of the rivastigmine patch between patients with AD with minimal WMHs and those with moderate WMHs. METHODS: Three hundred patients with mild to moderate AD were enrolled in this multicenter prospective open-label study and divided into two groups. Group 1 comprised patients with AD with minimal WMHs and group 2 comprised those with moderate WMHs. The patients were treated with a rivastigmine patch for 24 weeks. Efficacy measures were obtained at baseline and after 24 weeks. The primary endpoint was the change in the AD Assessment Scale-Cognitive subscale (ADAS-Cog) from the baseline to the end of the study. RESULTS: Of the 300 patients, there were 206 patients in group 1 and 94 patients in group 2. The intention-to-treat group comprised 198 patients (group 1, n = 136; group 2, n = 46) during the 24-week study period. Demographic factors did not differ between group 1 and group 2. There were no significant differences in change in ADAS-cog between group 1 (-0.62+/-5.70) and group 2 (-0.23+/-5.98) after the 24-week rivastigmine patch therapy (p = 0.378). The patients in group 1 had a 0.63-point improvement from baseline on the Frontal Assessment Battery, while group 2 had a 0.16-point decline compared to baseline at the end of the study (p = 0.037). The rates of adverse events (AEs) (42.6 vs. 40.3%) and discontinuation due to AEs (10.3% vs. 4.3%) did not differ between the groups. CONCLUSIONS: Although the efficacy and tolerability of rivastigmine patch therapy were not associated with WMH severity in patients with AD, some improvement in frontal function was observed in those with minimal WMHs. TRIAL REGISTRATION: ClinicalTrials.gov NCT01380288.
Title: Rivastigmine patch reduces the incidence of postoperative delirium in older patients with cognitive impairment Youn YC, Shin HW, Choi BS, Kim S, Lee JY, Ha YC Ref: Int J Geriatr Psychiatry, 32:1079, 2017 : PubMed
OBJECTIVE: To date, data regarding the efficacy of acetylcholinesterase inhibitors in preventing postoperative delirium (POD) are inconsistent and conflicting. Older individuals with cognitive dysfunction are thought to show POD more frequently. Our aim was to study the effectiveness of rivastigmine prophylaxis on the incidence, severity, and risk factors for POD in older patients with cognitive impairment undergoing hip fracture surgery. METHODS: Of 62 older patients with cognitive impairment about to undergo surgery after a hip fracture, 31 were randomly assigned to receive a rivastigmine patch from 3 days before to 7 days after the operation (Group I), and the other 31 did not receive a rivastigmine patch (Group II). The two groups were compared with regard to incidence and severity of delirium on postoperative days 2 or 3 and 7. Multivariate logistic regression analysis was performed to assess factors associated with POD. RESULTS: Postoperative delirium occurred in five Group I patients and 14 Group II patients (p = 0.013). The mean severity of delirium in the two groups as determined by the Delirium Rating Scale was 2.2 and 6.2 respectively (p = 0.033). The odds ratio for POD was 0.259 (95% CI: 0.074-0.905, p = 0.034) after adjusting for American Society of Anesthesiologists score (p = 0.058), age (p = 0.203), and gender (p = 0.560). There were no rivastigmine-related perioperative complications. CONCLUSION: Perioperative rivastigmine patch application could reduce the occurrence of POD in older patients with low cognitive status. Copyright (c) 2016 John Wiley & Sons, Ltd.
Title: Efficacy of Galantamine on Cognition in Mild-to-Moderate Alzheimer's Dementia after Failure to Respond to Donepezil Hwang TY, Ahn IS, Kim S, Kim DK Ref: Psychiatry Investig, 13:341, 2016 : PubMed
OBJECTIVE: This study compares the efficacy of the cholinesterase inhibitor (ChEI) galantamine on cognition in patients with mild-to-moderate Alzheimer's dementia (AD) who were either naive to ChEI drugs or who had failed a trial of the ChEI donepezil. METHODS: Outpatients with AD were sequentially referred for screening and enrollment. Current outpatients who had taken donepezil for at least 6 months without demonstrated efficacy on cognition were switched to galantamine (switched group). New outpatients with no ChEI prescription history were classified as the naive group and were given galantamine. The primary outcome measures for the between-group comparison were response rate on cognition at 26 and 52 weeks (categorical) and change on the Korean version of the Alzheimer's Disease Assessment Scale-cognitive subscale (dimensional). Secondary cognitive outcomes were measured using the subset of frontal executive function and the Korean Mini-Mental State Examination. RESULTS: Seventy outpatients were enrolled and 66 were analyzed by Intent-to-treat (ITT). There were 42 cases in the naive group and 24 in the switched group. Response rates did not differ at 26 weeks (71.4% naive vs. 58.3% switched; p=0.277) or at 52 weeks (59.5% naive vs. 41.6% switched; p=0.162). No significant differences were observed in the pattern of change over the 52 weeks on the primary and secondary cognitive scales. CONCLUSION: As the efficacy of galantamine on cognition was not inferior in the switched group compared to that in the naive group, switching ChEI drugs is clinically feasible for non-responding patients with mild-to-moderate AD.
Title: Characterization of T-DNA insertion mutants with decreased virulence in the entomopathogenic fungus Beauveria bassiana JEF-007 Kim S, Lee SJ, Nai YS, Yu JS, Lee MR, Yang YT, Kim JS Ref: Applied Microbiology & Biotechnology, 100:8889, 2016 : PubMed
The bean bug, Riptortus pedestris, is a major agricultural pest that reduces crop quality and value. Chemical pesticides have contributed to pest management, but resistance to these chemicals has significantly limited their use. Alternative strategies with different modes of action, such as entomopathogenic fungi, are therefore of great interest. Herein, we explored how entomopathogenic fungi can potentially be used to control the bean bug and focused on identifying virulence-related genes. Beauveria bassiana (JEF isolates) were assayed against bean bugs under laboratory conditions. One isolate, JEF-007, showed >80 % virulence by both spray and contact exposure methods. Agrobacterium tumefaciens-mediated transformation (AtMT) of JEF-007 generated 249 random transformants, two of which (B1-06 and C1-49) showed significantly reduced virulence against Tenebrio molitor and R. pedestris immatures. Both species were used for rapid screening of virulence-reduced mutants. The two transformants had different morphologies, conidial production, and thermotolerance than the wild type. To determine the localization of the randomly inserted T-DNA, thermal asymmetric interlaced (TAIL) PCR was conducted and analysis of the two clones found multiple T-DNA insertions (two in B1-06 and three in C1-49). Genes encoding complex I intermediate-associated protein 30 (CIA30) and the autophagy protein (Atg22) were possibly disrupted by the T-DNA insertion and might be involved in the virulence. This work provides a strong platform for future functional genetic studies of bean bug-pathogenic B. bassiana. The genes putatively involved in fungal virulence should be experimentally validated by knockdown in future studies.
UNLABELLED: The newly emerging Middle East respiratory syndrome coronavirus (MERS-CoV) causes a severe respiratory infection with a high mortality rate (~35%). MERS-CoV has been a global threat due to continuous outbreaks in the Arabian peninsula and international spread by infected travelers since 2012. From May to July 2015, a large outbreak initiated by an infected traveler from the Arabian peninsula swept South Korea and resulted in 186 confirmed cases with 38 deaths (case fatality rate, 20.4%). Here, we show the rapid emergence and spread of a mutant MERS-CoV with reduced affinity to the human CD26 receptor during the South Korean outbreak. We isolated 13 new viral genomes from 14 infected patients treated at a hospital and found that 12 of these genomes possess a point mutation in the receptor-binding domain (RBD) of viral spike (S) protein. Specifically, 11 of these genomes have an I529T mutation in RBD, and 1 has a D510G mutation. Strikingly, both mutations result in reduced affinity of RBD to human CD26 compared to wild-type RBD, as measured by surface plasmon resonance analysis and cellular binding assay. Additionally, pseudotyped virus bearing an I529T mutation in S protein showed reduced entry into host cells compared to virus with wild-type S protein. These unexpected findings suggest that MERS-CoV adaptation during human-to-human spread may be driven by host immunological pressure such as neutralizing antibodies, resulting in reduced affinity to host receptor, and thereby impairs viral fitness and virulence, rather than positive selection for a better affinity to CD26. IMPORTANCE: Recently, a large outbreak initiated by an MERS-CoV-infected traveler from the Middle East swept South Korea and resulted in 186 confirmed cases with 38 deaths. This is the largest outbreak outside the Middle East, and it raised strong concerns about the possible emergence of MERS-CoV mutations. Here, we isolated 13 new viral genomes and found that 12 of them possess a point mutation in the receptor-binding domain of viral spike protein, resulting in reduced affinity to the human cognate receptor, CD26, compared to the wild-type virus. These unexpected findings suggest that MERS-CoV adaptation in humans may be driven by host immunological pressure.
Organophosphates are powerful inhibitors of acetylcholinesterase, which is critical to nerve function. Despite continuous research for detecting the highly toxic organophosphates, a new and improved methodology is still needed. Herein we demonstrate simple-to-fabricate chemiresistive gas sensors using conducting-polymer polypyrrole (PPy) nanotube transducers, which are chemically specific and capable of recognizing sub-ppb concentrations (ca. 0.5 ppb) of dimethyl methylphosphonate (DMMP), a simulant of nerve agent sarin. Interestingly, the introduction of carboxylic groups on the surface of PPy nanotube transistors resulted in enhanced sensitivity to DMMP via intermolecular hydrogen bonding. Furthermore, it was found that the sensitivity of the nanotube transducer depended on the degree of the carboxylic group introduced. Finally, a sensor array composed of 5 different transducers including the carboxylated nanotubes exhibited excellent selectivity to DMMP in 16 vapor species.
Candida antarctica lipase B (CAL-B) exhibits remarkable enantioselectivity for various chiral sec-alcohols, and the enantioselectivity is structurally well-understood. Two substituents at the chiral center of a sec-alcohol separately bind two pockets, namely, large and medium binding pockets. It has been believed that the medium pocket is too small to accommodate a large substituent (larger than an ethyl group), and thus, bulky sec-alcohols bearing two large substituents have been regarded as a poor substrate for CAL-B. However, we found that CAL-B can catalyze the transesterification of N-Boc-protected rac-2-amino-1-phenylethanol (1a) enantioselectively with a moderate reaction rate. X-ray crystallography and computer modeling revealed that the rotation of the Leu278 side chain creates a space to accept the N-Boc-aminomethylene group of 1a. Moreover, a sec-alcohol substrate with less than one hydrogen atom at the gamma-position from the hydroxyl group is required to achieve a moderate reaction rate. On the basis of this observation, we diversified bulky N-Boc-protected rac-2-amino-1-arylethanols for the transesterifications with high enantioselectivities (E > 200).
BACKGROUND: The 'Asia-Pacific Expert Panel (APEX) for donepezil 23 mg' met in November 2015 to review evidence for the recently approved high dose of donepezil and to provide recommendations to help physicians in Asia make informed clinical decisions about using donepezil 23 mg in patients with moderate-to-severe Alzheimer's disease (AD). SUMMARY: In a global phase III study (study 326) in patients with moderate-to-severe AD, donepezil 23 mg/day demonstrated significantly greater cognitive benefits versus donepezil 10 mg/day, with a between-treatment difference in mean change in the Severe Impairment Battery score of 2.2 points (p < 0.001) in the overall population and 3.1 points (p < 0.001) in patients with advanced AD. A subanalysis of study 326 demonstrated that the benefits and risks associated with donepezil 23 mg/day versus donepezil 10 mg/day in Asian patients with moderate-to-severe AD were comparable to those in the global study population. KEY MESSAGE: Donepezil 23 mg is a valuable treatment for patients with AD, particularly those with advanced disease. The APEX emphasized the importance of patient selection (AD severity, tolerability of lower doses of donepezil, and absence of contraindications), a stepwise titration strategy for dose escalation, and appropriate monitoring and counseling of patients and caregivers in the management of patients with AD.
Title: 1H-NMR-based metabolomic study on toxicity of methomyl and methidathion in fish Yoon D, Kim S, Lee M, Yoon C Ref: J Environ Sci Health B, :1, 2016 : PubMed
A 1H-nuclear magnetic resonance (NMR) spectroscopy with multivariate analysis was applied to detect the toxicity of antiacetylcholinesterase insecticides, methomyl (methyl (1E)-N-(methylcarbamoyloxy)ethanimidothioate) and methidathion (3-(dimethoxyphosphinothioyl sulfanylmethyl)-5-methoxy-1,3,4-thiadiazol-2-one), using zebrafish (Danio rerio) and Chinese bleak (Aphyocypris chinensis). Generally, methomyl and methidathion have been believed not to highly accumulate in fish tissues. However, these pesticides showed their toxicity by altering patterns of whole-body metabolites in neurotransmitter balance, energy metabolism, oxidative stress, and muscle maintenance in low concentrations. We used Pearson correlation analysis to contextualize the metabolic markers in pesticide treated groups. We observed that the positive correlations of choline with acetate and betaine in untreated control were shifted to null correlations showing acetylcholinesterase specific toxicity. This research demonstrated the applicability and potential of NMR metabolomics in detecting toxic effects of insecticide with a modicum of concentrations in aquatic environment.
Title: Expression and purification of biologically active recombinant human paraoxonase 1 from a Drosophila S2 stable cell line Yun H, Yu J, Kim S, Lee N, Lee J, Lee S, Kim ND, Yu C, Rho J Ref: Protein Expr Purif, 131:34, 2016 : PubMed
Many pesticides and chemical warfare nerve agents are highly toxic organophosphorus compounds (OPs), which inhibit acetylcholinesterase activity. Human paraoxonase 1 (PON1) has demonstrated significant potential for use as a catalytic bioscavenger capable of hydrolyzing a broad range of OPs. However, there are several limitations to the use of human PON1 as a catalytic bioscavenger, including the relatively difficult purification of PON1 from human plasma and its dependence on the presence of hydrophobic binding partners to maintain stability. Therefore, research efforts to efficiently produce recombinant human PON1 are necessary. In this study, we developed a Drosophila S2 stable cell line expressing recombinant human PON1. The recombinant human PON1 was fused with the human immunoglobulin Fc domain (PON1-hFc) to improve protein stability and purification efficiency. We purified the recombinant human PON1-hFc from the S2 stable cell line and characterized its enzymatic properties for OP hydrolysis. We purified the recombinant human PON1-hFc from the S2 stable cell line and characterized its enzymatic properties for OP hydrolysis compared with those of the recombinant human PON1 derived from E. coli. We observed that the recombinant human PON1-hFc is functionally more stable for OP hydrolyzing activities compared to the recombinant human PON1. The catalytic efficiency of the recombinant PON1-hFc towards diisopropyl fluorophosphate (DFP, 0.26 x 106 M-1 min-1) and paraoxon hydrolysis (0.015 x 106 M-1 min-1) was 1.63- and 1.24-fold higher, respectively, than the recombinant human PON1. Thus, we report that the recombinant PON1-hFc exerts hydrolytic activity against paraoxon and DFP.
Title: Enhancing extracellular lipolytic enzyme production in an arctic bacterium, Psychrobacter sp. ArcL13, by using statistical optimization and fed-batch fermentation Kim S, Wi AR, Park HJ, Kim D, Kim HW, Yim JH, Han SJ Ref: Preparative Biochemistry & Biotechnology, 45:348, 2015 : PubMed
A strain isolated from seawater samples in the Chuckchi Sea and exhibiting extracellular lipolytic activity was identified using 16S rRNA gene sequence analysis as Psychrobacter sp. ArcL13. The lipolytic enzyme exhibited cold-active properties and high hydrolytic activity toward p-nitrophenyl caprylate (C8), p-nitrophenyl decanoate (C10), and sunflower oil. Statistical optimization of the medium components was performed to enhance the production of cold-active extracellular lipolytic activity. Glucose, yeast extract (YE), and NaCl were selected as the main efficient nutrient sources. Fed-batch fermentation using optimized medium with concentrated YE as the main feeding material showed a maximum lipolytic activity of 10.7 U/mL, which was a 21-fold increase in production over unoptimized flask culture conditions. The information obtained in the present study could prove applicable to the production of cold-active lipase on a large scale.
Title: Improved enantioselectivity of thermostable esterase from Archaeoglobus fulgidus toward (S)-ketoprofen ethyl ester by directed evolution and characterization of mutant esterases Kim J, Kim S, Yoon S, Hong E, Ryu Y Ref: Applied Microbiology & Biotechnology, 99:6293, 2015 : PubMed
Thermostable esterases have potential applications in various biotechnology industries because of their resistance to high temperature and organic solvents. In a previous study, we isolated an esterase from Archaeoglobus fulgidus DSM 4304 (Est-AF), which showed high thermostability but low enantioselectivity toward (S)-ketoprofen ethyl ester. (R)-ketoprofenor (S)-ketoprofenis produced by esterase hydrolysis of the ester bond of (R,S)-ketoprofen ethyl ester and (S)-ketoprofen has better pharmaceutical activity and lower side effects than (R)-ketoprofen. Therefore, we have generated mutants of Est-AF that retained high thermostability whilst improving enantioselectivity. A library of Est-AF mutants was created by error-prone polymerase chain reaction, and mutants with improved enantioselectivity were isolated by site-saturation mutagenesis. The regions of Est-AF containing amino acid mutations were analyzed by homology modeling of its three-dimensional structure, and structure-based explanations for the changes in enantioselectivity are proposed. Finally, we isolated two mutants showing improved enantioselectivity over Est-AF (ee% = -16.2 +/- 0.2 and E = 0.7 +/- 0.0): V138G (ee% = 35.9 +/- 1.0 and E = 3.0 +/- 0.1) and V138G/L200R (ee% = 89.2 +/- 0.2 and E = 19.5 +/- 0.5). We also investigated various characteristics of these mutants and found that the mutants showed similar thermostability and resistance to additives or organic solvents to Est-AF, without a significant trade-off between activity and stability.
Title: Insights into the Lactonase Mechanism of Serum Paraoxonase 1 (PON1): Experimental and Quantum Mechanics/Molecular Mechanics (QM/MM) Studies Le QA, Kim S, Chang R, Kim YH Ref: J Phys Chem B, 119:9571, 2015 : PubMed
Serum paraoxonase 1 (PON1) is a versatile enzyme for the hydrolysis of various substrates (e.g., lactones, phosphotriesters) and for the formation of a promising chemical platform gamma-valerolactone. Elucidation of the PON1-catalyzed lactonase reaction mechanism is very important for understanding the enzyme function and for engineering this enzyme for specific applications. Kinetic study and hybrid quantum mechanics/molecular mechanics (QM/MM) method were used to investigate the PON1-catalyzed lactonase reaction of gamma-butyrolactone (GBL) and (R)-gamma-valerolactone (GVL). The activation energies obtained from the QM/MM calculations were in good agreement with the experiments. Interestingly, the QM/MM energy barriers at MP2/3-21G(d,p) level for the lactonase of GVL and GBL were respectively 14.3-16.2 and 11.5-13.1 kcal/mol, consistent with the experimental values (15.57 and 14.73 kcal/mol derived from respective kcat values of 36.62 and 147.21 s(-1)). The QM/MM energy barriers at MP2/6-31G(d) and MP2/6-31G(d,p) levels were also in relatively good agreements with the experiments. Importantly, the difference in the QM/MM energy barriers at MP2 level with all investigated basis sets for the lactonase of GVL and GBL were in excellent agreement with the experiments (0.9-3.1 and 0.8 kcal/mol, respectively). A detailed mechanism for the PON1-catalyzed lactonase reaction was also proposed in this study.
Title: Association of the choline acetyltransferase gene with responsiveness to acetylcholinesterase inhibitors in Alzheimer's disease Yoon H, Myung W, Lim SW, Kang HS, Kim S, Won HH, Carroll BJ, Kim DK Ref: Pharmacopsychiatry, 48:111, 2015 : PubMed
INTRODUCTION: The response to acetylcholinesterase inhibitors (AChEIs) of Alzheimer's disease (AD) patients varies depending on the genetic characteristics of the patient. We have examined the association of response to AChEIs and genetic polymorphisms in AD patients. METHODS: 158 patients with AD underwent treatment with AChEIs, and the therapeutic effect was assessed with the Korean version of the Mini Mental State Examination (K-MMSE). The association of 25 SNPs located in 3 genes (CHAT, CHT and ACHE) with changes in the K-MMSE score was analyzed. RESULTS: The response to AChEIs in AD patients was significantly associated with 2 SNPs on the intronic region of CHAT rs2177370 (uncorrected P=0.0025, FDR controlled P=0.026) and rs3793790 (uncorrected P=0.0024, FDR controlled P=0.026). CONCLUSION: The results of our study confirmed again that genetic polymorphism of CHAT has an influence on drug response in AD.
Deposition of amyloid-beta (Abeta) in the cerebral cortex is thought to be a pivotal event in Alzheimer's disease (AD) pathogenesis with a significant genetic contribution. Molecular imaging can provide an early noninvasive phenotype, but small samples have prohibited genome-wide association studies (GWAS) of cortical Abeta load until now. We employed florbetapir ((18)F) positron emission tomography (PET) imaging to assess brain Abeta levels in vivo for 555 participants from the Alzheimer's Disease Neuroimaging Initiative (ADNI). More than six million common genetic variants were tested for association to quantitative global cortical Abeta load controlling for age, gender and diagnosis. Independent genome-wide significant associations were identified on chromosome 19 within APOE (apolipoprotein E) (rs429358, P=5.5 x 10(-14)) and on chromosome 3 upstream of BCHE (butyrylcholinesterase) (rs509208, P=2.7 x 10(-8)) in a region previously associated with serum BCHE activity. Together, these loci explained 15% of the variance in cortical Abeta levels in this sample (APOE 10.7%, BCHE 4.3%). Suggestive associations were identified within ITGA6, near EFNA5, EDIL3, ITGA1, PIK3R1, NFIB and ARID1B, and between NUAK1 and C12orf75. These results confirm the association of APOE with Abeta deposition and represent the largest known effect of BCHE on an AD-related phenotype. BCHE has been found in senile plaques and this new association of genetic variation at the BCHE locus with Abeta burden in humans may have implications for potential disease-modifying effects of BCHE-modulating agents in the AD spectrum.
Skeletal muscle microvascular blood flow (MBF) increases in response to physiologic hyperinsulinemia. This vascular action of insulin may facilitate glucose uptake. We hypothesized that epoxyeicosatrienoic acids (EETs), a family of arachadonic acid-derived endothelium-derived hyperpolarizing factors, is a mediator of insulin's microvascular effects. Contrast-enhanced ultrasound (CEU) was performed to quantify skeletal muscle capillary blood volume (CBV) and MBF in wild-type and obese insulin-resistant (db/db) mice after administration of vehicle or tAUCB, an inhibitor of soluble epoxide hydrolase which converts EETs to less active dihydroxyeicosatrienoic acids. Similar studies were performed in rats pre-treated with L-NAME. CEU was also performed in rats undergoing a euglycemic hyperinsulinemic clamp, half of which were pre-treated with the epoxygenase inhibitor MS-PPOH to inhibit EET synthesis. In both wild type and db/db mice, intravenous tAUCB produced an increase in CBV (65-100% increase at 30 min, p<0.05) and in MBF. In db/db/ mice tAUCB also reduced plasma glucose by approximately 15%. In rats pretreated with L-NAME, tAUCB after produced a significant approximately 20% increase in CBV indicating a component of vascular response independent of nitric oxide (NO) production. Hyperinsulinemic clamp produced a time-dependent increase in MBF (19+/-36 and 76+/-49% at 90 min, p=0.026) mediated in part by an increase in CBV. Insulin-mediated changes in both CBV and MBF during the clamp were entirely blocked MS-PPOH. We conclude that EETs are a mediator of insulin-mediated augmentation in skeletal muscle perfusion and are involved in regulating changes in CBV during hyperinsulinemia.
Title: Characterization and a point mutational approach of a psychrophilic lipase from an arctic bacterium, Bacillus pumilus Wi AR, Jeon SJ, Kim S, Park HJ, Kim D, Han SJ, Yim JH, Kim HW Ref: Biotechnol Lett, 36:1295, 2014 : PubMed
A bacterium with lipolytic activity was isolated from the Chukchi Sea within the Arctic Ocean. The lipase BpL5 from the isolate, Bacillus pumilus ArcL5, belongs to subfamily 4 of lipase family I. The optimum pH and temperature of the recombinant enzyme BpL5, as expressed in Escherichia coli, were 9.0 and 20 degrees C, respectively. The enzyme retained 85 % of its activity at 5 degrees C. There was a significant difference between temperatures for maximal activity (20 degrees C) and for protein denaturation (approx. 45 degrees C). The enzyme preferred middle-chain (C8) p-nitrophenyl substrates. Two mutants, S139A and S139Y, were rationally designed based on the 3D-structure model, and their activities were compared with that of the wild type. The both mutants showed significantly improved activity against tricaprylin.
Title: Enzymatic biodiesel synthesis in semi-pilot continuous process in near-critical carbon dioxide Lee M, Lee D, Cho J, Kim S, Park C Ref: Appl Biochem Biotechnol, 171:1118, 2013 : PubMed
A semi-pilot continuous process (SPCP) for enzymatic biodiesel synthesis utilizing near-critical carbon dioxide (NcCO) as the reaction medium was developed with the aim of reducing the reaction time and alleviating the catalyst inhibition by methanol. Biodiesel synthesis was evaluated in both lab-scale and semi-pilot scale reactors (batch and continuous reactors). In a SPCP, the highest conversion (~99.9 %) in four and a half hours was observed when three-step substrate (methanol) addition (molar ratio [oil/methanol] = 1:1.3) was used and the reaction mixture containing enzyme (Lipozyme TL IM, 20 wt.% of oil) was continuously mixed (agitation speed = 300 rpm) at 30 degreeC and 100 bar in a CO environment. The biodiesel produced from canola oil conformed to the fuel standard (EU) even without additional downstream processing, other than glycerol separation and drying.
Title: Draft Genome Sequence of Cladonia macilenta KoLRI003786, a Lichen-Forming Fungus Producing Biruloquinone Park SY, Choi J, Kim JA, Jeong MH, Kim S, Lee YH, Hur JS Ref: Genome Announc, 1:, 2013 : PubMed
The lichen-forming fungus Cladonia macilenta strain KoLRI003786 is capable of producing an acetylcholinesterase inhibitor, biruloquinone, which effectively prevents neurodegeneration in Alzheimer's disease. Laying the foundation to unravel the biruloquinone biosynthetic pathway, we present the 37.11-Mb draft genome sequence of strain KoLRI003786.
Title: Complete Genome Sequence of Raoultella ornithinolytica Strain B6, a 2,3-Butanediol-Producing Bacterium Isolated from Oil-Contaminated Soil Shin SH, Um Y, Beak JH, Kim S, Lee S, Oh MK, Kim YR, Lee J, Yang KS Ref: Genome Announc, 1:, 2013 : PubMed
Here we report the full genome sequence of Raoultella ornithinolytica strain B6, a Gram-negative aerobic bacillus belonging to the family Enterobacteriaceae. This 2,3-butanediol-producing bacterium was isolated from oil-contaminated soil on Backwoon Mountain in South Korea. Strain B6 contains 5,398,151 bp with 4,909 protein-coding genes, 104 structural RNAs, and 55.88% G+C content.
A novel aporphine alkaloid was isolated from the leaves of Epimedium koreanum Nakai during activity-guided fractionation in search of compounds with an anticholinesterase activity. The structure of the new compound was assigned as 1,10-methoxy-7-hydroxy-aporphine (1), which we have named epimediphine. Unambiguous (1)H-NMR and (13)C-NMR data for epimediphine are described. Epimediphine inhibited an acetylcholinesterase (AchE) activity in a dose-dependent manner with an IC50 value of 3.1 microM. Meanwhile, tacrine, dehydroevodiamine and physostigmine, which are therapeutic drugs or candidates for AD, exhibited an anti-AchE activity with IC50 values of 0.4, 37.9 and 0.12 microM, respectively.
CONTEXT: Chamaecyparis obtusa Sieb. & Zucc., Endlicher (Cupressaceae) forest bathing or aromatherapy has been shown in various studies to have biological functions such as anticancer, antiallergies, antiinflammatory, and antioxidant activity. However, no reports exist on the pharmacological or biological activities of the essential oil of C. obtusa (EOCO) or its effects on central nervous system. OBJECTIVE: The aggregation and formation of beta-amyloid peptides (Abeta) into fibrils are central events in the pathogenesis of Alzheimer's disease (AD), and overproduction and aggregation of Abeta into oligomers have been known to trigger neurotoxicity. In this study, we investigated the effects of inhaled EOCO on cognitive function and neuronal apoptosis in rats intrahippocampally injected with Abeta. MATERIALS AND METHODS: To model AD, 4 mug of aggregated Abeta was injected into the hippocampus. To test the effects of EOCO, behavioral performance in the Morris water maze was tested 4 days after injection. After behavioral testing, brain sections were prepared for TTC staining and TUNEL assay. RESULTS: Inhaled EOCO protected spatial learning and memory from the impairments induced by Abeta(1-40) injection. In addition, the behavioral deficits accompanying Abeta(1-40)-induced AD were attenuated by inhalation of EOCO. Furthermore, acetylcholinesterase (AChE) activity and neuronal apoptosis were significantly inhibited in rats treated with Abeta(1-40) and EOCO compared to rats treated only with Abeta(1-40). DISCUSSION AND CONCLUSION: EOCO suppressed both AD-related neuronal cell apoptosis and AD-related dysfunction of the memory system. Thus, the results of this study support EOCO as a candidate drug for the treatment of AD.
Title: Construction of a high-resolution linkage map of Rfd1, a restorer-of-fertility locus for cytoplasmic male sterility conferred by DCGMS cytoplasm in radish (Raphanus sativus L.) using synteny between radish and Arabidopsis genomes Cho Y, Lee YP, Park BS, Han TH, Kim S Ref: Theor Appl Genet, 125:467, 2012 : PubMed
Cytoplasmic male sterility caused by Dongbu cytoplasmic and genic male-sterility (DCGMS) cytoplasm and its nuclear restorer-of-fertility locus (Rfd1) with a linked molecular marker (A137) have been reported in radish (Raphanus sativus L.). To construct a linkage map of the Rfd1 locus, linked amplified fragment length polymorphism (AFLP) markers were screened using bulked segregant analysis. A 220-bp linked AFLP fragment sequence from radish showed homology with an Arabidopsis coding sequence. Using this Arabidopsis gene sequence, a simple PCR marker (A220) was developed. The A137 and A220 markers flanked the Rfd1 locus. Two homologous Arabidopsis genes with both marker sequences were positioned on Arabidopsis chromosome-3 with an interval of 2.4 Mb. To integrate the Rfd1 locus into a previously reported expressed sequence tag (EST)-simple sequence repeat (SSR) linkage map, the radish EST sequences located in three syntenic blocks within the 2.4-Mb interval were used to develop single nucleotide polymorphism (SNP) markers for tagging each block. The SNP marker in linkage group-2 co-segregated with male fertility in an F(2) population. Using radish ESTs positioned in linkage group-2, five intron length polymorphism (ILP) markers and one cleaved amplified polymorphic sequence (CAPS) marker were developed and used to construct a linkage map of the Rfd1 locus. Two closely linked markers delimited the Rfd1 locus within a 985-kb interval of Arabidopsis chromosome-3. Synteny between the radish and Arabidopsis genomes in the 985-kb interval were used to develop three ILP and three CAPS markers. Two ILP markers further delimited the Rfd1 locus to a 220-kb interval of Arabidopsis chromosome-3.
Title: Improved high-pressure enzymatic biodiesel batch synthesis in near-critical carbon dioxide Lee M, Lee D, Cho JK, Cho J, Han J, Park C, Kim S Ref: Bioprocess Biosyst Eng, 35:105, 2012 : PubMed
The enzymatic synthesis of biodiesel by a high-pressure semi-continuous process in near-critical carbon dioxide (NcCO(2)) was studied. Biodiesel synthesis was evaluated in both batch and semi-continuous systems to develop an effective process. Batch processing demonstrated the advantageous properties of NcCO(2) as an alternative reaction medium. Three immobilized lipases (Novozym 435, Lipozyme RM IM, and Lipozyme TL IM from Novozymes) were tested, with Lipozyme TL IM the most effective, showing the highest conversion. Biodiesel conversion from several edible and non-edible oil feedstocks reached >92%. Higher conversion (99.0%) was obtained in a shorter time by employing repeated batch processes with optimized conditions: 44.3 g (500 mM) canola oil, a substrate molar ratio (methanol:oil) of 3:1, an enzyme loading of 20 wt% (of the oil used), at 30 degreeC, 100 bar, and 300 rpm agitation. The enzyme maintained 80.2% of its initial stability after being reused eight times. These results suggest that this method produces biodiesel energy-efficiently and environment-friendly.
Lipoprotein lipase LPL plays an essential role in the regulation of high-density lipoprotein cholesterol HDLC and triglyceride levels which have been closely associated with cardiovascular diseases Genetic studies in European have shown that LPL single-nucleotide polymorphisms SNPs are strongly associated with lipid levels However studies about the influence of interactions between LPL SNPs and lifestyle factors have not been sufficiently performed Here we examine if LPL polymorphisms as well as their interaction with lifestyle factors influence lipid concentrations in a Korean population A two-stage association study was performed using genotype data for SNPs on the LPL gene including the 3 flanking region from 7,536 stage 1 and 3,703 stage 2 individuals The association study showed that 15 SNPs and 4 haplotypes were strongly associated with HDLC lowest p 2.86 x 10(-22 and triglyceride levels lowest p 3.0 x 10(-15 Interactions between LPL polymorphisms and lifestyle factors lowest p 9.6 x 10(-4 were also observed on lipid concentrations These findings suggest that there are interaction effects of LPL polymorphisms with lifestyle variables including energy intake fat intake smoking and alcohol consumption as well as effects of LPL polymorphisms themselves on lipid concentrations in a Korean population.
Title: Genome sequence of Vibrio sp. strain EJY3, an agarolytic marine bacterium metabolizing 3,6-anhydro-L-galactose as a sole carbon source Roh H, Yun EJ, Lee S, Ko HJ, Kim S, Kim BY, Song H, Lim KI, Kim KH, Choi IG Ref: Journal of Bacteriology, 194:2773, 2012 : PubMed
The metabolic fate of 3,6-anhydro-L-galactose (L-AHG) is unknown in the global marine carbon cycle. Vibrio sp. strain EJY3 is an agarolytic marine bacterium that can utilize L-AHG as a sole carbon source. To elucidate the metabolic pathways of L-AHG, we have sequenced the complete genome of Vibrio sp. strain EJY3.
Title: Identification, crystallization and preliminary X-ray diffraction analysis of esterase A from Caulobacter crescentus CB15, a family VIII lipolytic enzyme Ryu BH, Ngo TD, Jang E, Kim S, Ju H, Kim KK, Kim TD Ref: Acta Crystallographica Sect F Struct Biol Cryst Commun, 68:560, 2012 : PubMed
The structures and functions of family VIII lipolytic enzymes, which have moderate sequence identity to class C beta-lactamases and penicillin-binding proteins, are largely unknown. Here, the X-ray crystallographic study of a family VIII esterase from Caulobacter crescentus CB15 (CcEstA) is described. Sequence analysis revealed that CcEstA has a conserved serine residue within the S-X-X-K motif which acts as a catalytic nucleophile. Recombinant protein containing an N-terminal His tag was expressed in Escherichia coli and purified to homogeneity. Functional studies showed that CcEstA acts on alpha- and beta-naphthyl acetate as substrates. In addition, it can catalyze the hydrolysis of ketoprofen ethyl ester, a highly useful product in industrial applications. CcEstA was crystallized using a solution consisting of 1.0 M potassium/sodium tartrate, 0.1 M imidazole pH 8.0, 0.2 M NaCl, and X-ray diffraction data were collected to a resolution of 1.62 A with an R(merge) of 9.4%. The crystals of CcEstA belonged to space group C222(1), with unit-cell parameters a = 172.23, b = 176.68, c = 47.93 A. Structure determination is in progress.
Here we report the full genome sequence of Klebsiella pneumoniae KCTC 2242,consisting of a 5.26-Mb chromosome (57.6% GC%; 5,035 genes [4,923 encoding known proteins, 112 RNA genes]) and a 202-kb plasmid (50.2% GC%; 229 genes [229 encoding known proteins]).
This is the first complete genome sequence of the Enterobacter aerogenes species. Here we present the genome sequence of E. aerogenes KCTC 2190, which contains 5,280,350 bp with a G + C content of 54.8 mol%, 4,912 protein-coding genes, and 109 structural RNAs.
BACKGROUND: The Asia-specific PLA2G7 994G-T transversion leads to V279F substitution within the lipoprotein-associated phospholipase-A2 (Lp-PLA(2)) and to absence of enzyme activity in plasma. This variant offers a unique natural experiment to assess the role of Lp-PLA(2) in the pathogenesis of coronary artery disease (CAD) in humans. Given conflicting results from mostly small studies, a large two-stage case-control study was warranted. METHODOLOGY/PRINCIPAL FINDINGS: PLA2G7 V279F genotypes were initially compared in 2890 male cases diagnosed with CAD before age 60 with 3128 male controls without CAD at age 50 and above and subsequently in a second independent male dataset of 877 CAD cases and 1230 controls. In the first dataset, the prevalence of the 279F null allele was 11.5% in cases and 12.8% in controls. After adjustment for age, body mass index, diabetes, smoking, glucose and lipid levels, the OR (95% CI) for CAD for this allele was 0.80 (0.66-0.97, p = 0.02). The results were very similar in the second dataset, despite lower power, with an allele frequency of 11.2% in cases and 12.5% in controls, leading to a combined OR of 0.80 (0.69-0.92), p = 0.002. The magnitude and direction of this genetic effect were fully consistent with large epidemiological studies on plasma Lp-PLA(2) activity and CAD risk. CONCLUSIONS: Natural deficiency in Lp-PLA(2) activity due to carriage of PLA2G7 279F allele protects from CAD in Korean men. These results provide evidence for a causal relationship between Lp-PLA(2) and CAD, and support pharmacological inhibition of this enzyme as an innovative way to prevent CAD.
The acetylcholinesterase (AChE) is important to terminate acetylcholine-mediated neurotransmission at cholinergic synapses. The pivotal role of AChE in apoptosome formation through the interactions with cytochrome c (Cyt c) was demonstrated in recent study. In order to investigate the proper binding conformation between the human AChE (hAChE) and human Cyt c (hCyt c), macro-molecular docking simulation was performed using DOT 2.0 program. The hCyt c was bound to peripheral anionic site (PAS) on hAChE and binding mode of the docked conformation was very similar to the reported crystal structure of the AChE and fasciculin-II (Fas-II) complex. Two 10ns molecular dynamics (MD) simulations were carried out to refine the binding mode of docked structure and to observe the differences of the binding conformations between the absent (Apo) and presence (Holo) of heme group. The key hydrogen bonding residues between hAChE and hCyt c proteins were found in Apo and Holo systems, as well as each Tyr341 and Trp286 residue of hAChE was participated in cation-pi (pi) interactions with Lys79 of hCyt c in Apo and Holo systems, respectively. From the present study, although the final structures of the Apo and Holo systems have similar binding pattern, several differences were investigated in flexibilities, interface interactions, and interface accessible surface areas. Based on these results, we were able to predict the reasonable binding conformation which is indispensable for apoptosome formation.
Title: Improvement of enzymatic biodiesel production by controlled substrate feeding using silica gel in solvent free system Lee M, Lee J, Lee D, Cho J, Kim S, Park C Ref: Enzyme Microb Technol, 49:402, 2011 : PubMed
A silica gel-based substrate feeding system was developed to prevent methanol inhibiting the catalyst during enzymatic biodiesel synthesis. In the system, silica gel swelled upon methanol addition and subsequently released it in a controlled manner to prevent excess methanol affecting the enzyme. Biodiesel was synthesized by the enzymatic transesterification of canola oil with methanol. For this reaction, enzyme loading, methanol/oil molar ratio, silica gel dosage, glycerol content, and methanol feeding method were tested using commercial immobilized enzymes (Novozym 435 and Lipozyme RM IM from Novozymes). The results showed that conversion was highest with controlled substrate feeding rather than direct methanol addition, suggesting that the method developed here can easily prevent enzyme inhibition by limiting methanol concentration to an acceptable level.
Title: Complete genome sequencing of Lactobacillus acidophilus 30SC, isolated from swine intestine Oh S, Roh H, Ko HJ, Kim S, Kim KH, Lee SE, Chang IS, Choi IG Ref: Journal of Bacteriology, 193:2882, 2011 : PubMed
Lactobacillus acidophilus 30SC has been isolated from swine intestines and considered a probiotic strain for dairy products because of its ability to assimilate cholesterol and produce bacteriocins. Here, we report the complete genome sequence of Lactobacillus acidophilus 30SC (2,078,001 bp) exhibiting strong acid resistance and enhanced bile tolerance.
Verrucosispora maris AB-18-032 is a marine actinomycete that produces atrop-abyssomicin C and proximicin A, both of which have novel structures and modes of action. In order to understand the biosynthesis of these compounds, to identify further biosynthetic potential, and to facilitate rational improvement of secondary metabolite titers, we have sequenced the complete 6.7-Mb genome of Verrucosispora maris AB-18-032.
A synergistic combination of two next-generation sequencing platforms with a detailed comparative BAC physical contig map provided a cost-effective assembly of the genome sequence of the domestic turkey (Meleagris gallopavo). Heterozygosity of the sequenced source genome allowed discovery of more than 600,000 high quality single nucleotide variants. Despite this heterozygosity, the current genome assembly ( approximately 1.1 Gb) includes 917 Mb of sequence assigned to specific turkey chromosomes. Annotation identified nearly 16,000 genes, with 15,093 recognized as protein coding and 611 as non-coding RNA genes. Comparative analysis of the turkey, chicken, and zebra finch genomes, and comparing avian to mammalian species, supports the characteristic stability of avian genomes and identifies genes unique to the avian lineage. Clear differences are seen in number and variety of genes of the avian immune system where expansions and novel genes are less frequent than examples of gene loss. The turkey genome sequence provides resources to further understand the evolution of vertebrate genomes and genetic variation underlying economically important quantitative traits in poultry. This integrated approach may be a model for providing both gene and chromosome level assemblies of other species with agricultural, ecological, and evolutionary interest.
Neuroactive small molecules are indispensable tools for treating mental illnesses and dissecting nervous system function. However, it has been difficult to discover novel neuroactive drugs. Here, we describe a high-throughput, behavior-based approach to neuroactive small molecule discovery in the zebrafish. We used automated screening assays to evaluate thousands of chemical compounds and found that diverse classes of neuroactive molecules caused distinct patterns of behavior. These 'behavioral barcodes' can be used to rapidly identify new psychotropic chemicals and to predict their molecular targets. For example, we identified new acetylcholinesterase and monoamine oxidase inhibitors using phenotypic comparisons and computational techniques. By combining high-throughput screening technologies with behavioral phenotyping in vivo, behavior-based chemical screens can accelerate the pace of neuroactive drug discovery and provide small-molecule tools for understanding vertebrate behavior.
Title: Ethanol Extract and Saponin of Platycodon grandiflorum Ameliorate Scopolamine-Induced Amnesia in Mice Moon MK, Ahn JY, Kim S, Ryu SY, Kim YS, Ha TY Ref: J Med Food, 13:584, 2010 : PubMed
This study was carried out to examine the effects of ethanol extract (EXPG) and saponin (SAP) from Platycodon grandiflorum on scopolamine-induced amnesia in mice. Fifty male ICR mice were assigned to five groups--normal (normal diet + saline), control (normal diet + scopolamine), EXPG 0.2% (normal diet + 0.2% EXPG + scopolamine), EXPG 0.5% (normal diet + 0.5% EXPG + scopolamine), and SAP 0.02% (normal diet + 0.02% SAP + scopolamine)--and fed each diet ad libitum. After 4 weeks of feeding the appropriate diet, scopolamine (1 mg/kg, i.p.) was given to mice 45 minutes before the passive avoidance and Morris water maze tasks. Both the EXPG groups and the SAP group exhibited significant amelioration of scopolamine-induced amnesia as measured in both the passive avoidance task and the Morris water maze task. Moreover, acetylcholinesterase (AChE) activity and the levels of thiobarbituric acid-reactive substance (TBARS) in the serum and brain of the EXPG groups were lower than those of the control group. These results suggest that EXPG may improve the cognitive deficit caused by scopolamine and that these effects might be due to EXPG mediated by inhibition of AChE activity and inhibition of TBARS.
In Oriental medicine, roots of Polygala tenuifolia Willdenow have been known to be an important herb that exhibits sedative effects in insomnia, palpitation with anxiety, restlessness, and disorientation in humans. We previously reported that BT-11, extracted from those roots, improved scopolamine-induced amnesia in rats and inhibited acetylcholinesterase activities in vitro. Therefore, we proposed that BT-11 could remedy stress-induced memory deficits in rats. In this study, the stress-induced memory impairments in rats were significantly reversed almost to the control level by BT-11 treatment. To seek an active component of BT-11 that plays an important role in antipsychotic effects, we compared BT-11 with 3,4,5-trimethoxycinnamic acid (TMCA), which is a constituent of those root extracts. However, the effects of TMCA were less or were not consistent with those of BT-11 in some of tests. In particular, BT-11 reversed the stress-induced reduction of glucose utilization by [(18)fluorodeoxyglucose]FDG-PET and the levels of neural cell adhesion molecule (NCAM) in rat brains to the control levels, whereas TMCA did not. Therefore, BT-11 improved stress-induced memory impairments through increment of glucose utilization and total NCAM levels in rat brains. In conclusion, BT-11 may be strongly effective against stress-induced amnesia in rats, through the combined effects of TMCA and other active components of BT-11.
Decursinol, found in the roots of Angelica gigas Nakai, has been traditionally used to treat anemia and other various diseases. Recently, numerous biological activities such as cytotoxic effect on leukemia cells, and antitumor, neuroprotection, and antibacterial activities have been reported for this compound. Although a number of proteins including protein kinase C, androgen receptor, and acetylcholinesterase were proposed as molecular targets responsible for the activities of decursinol, they are not enough to explain such a diverse biological activity mentioned above. In this study, we employed a chemical proteomic approach, leading to identification of seven proteins as potential proteins interacting with decursinol. Most of the proteins contain a defined ATP or nucleic acid binding domain and have been implied to be involved in the pathogenesis and progression of various human diseases including cancer, autoimmune disorders, or neurodegenerative diseases. The present results may provide clues to understand the molecular mechanism of the biological activities shown by decursinol, an anticancer natural product.
Title: Highly enantioselective dynamic kinetic resolution of 1,2-diarylethanols by a lipase-ruthenium couple Kim MJ, Choi YK, Kim S, Kim D, Han K, Ko SB, Park J Ref: Org Lett, 10:1295, 2008 : PubMed
A practical procedure has been developed for the dynamic kinetic resolution of 1,2-diarylethanols. This procedure employs a highly enantioselective lipase from Pseudomonas stutzeri (trade name, lipase TL) as the resolution catalyst and a ruthenium complex as the racemization catalyst. Sixteen 1,2-diarylethanols have been efficiently resolved to provide their acetyl derivatives with good yields (95-97%) and high enantiomeric excesses (96-99%).
Title: Genetic variations in soluble epoxide hydrolase and graft function in kidney transplantation Lee SH, Lee J, Cha R, Park MH, Ha JW, Kim S, Kim YS Ref: Transplant Proc, 40:1353, 2008 : PubMed
BACKGROUND: Epoxyeicosatrienoic acids (EETs) are endothelium-derived hyperpolarizing factors that contribute renal protective actions. The aim of this study was to identify the association between genetic variations in soluble epoxide hydrolase (EPHX2, EET-metabolizing enzyme) and kidney allograft dysfunction. MATERIALS AND METHODS: Data from 204 kidney transplant donor-recipient pairs were examined for polymorphisms of exon 8 (R287Q, rs751141 G/A) and 3' untranslated region (3' UTR, rs1042032 A/G) of the EPHX2 gene and correlated with clinical data. RESULTS: The mean duration of follow-up for recipients was 58 +/- 45.3 months who were 39 +/- 11.8 years old at the time of operation and displayed estimated glomerular filtration rate (eGFR) of 68 +/- 16.5 mL/min/1.73 m2 at 1 month after transplantation. AA, AG, and GG genotype frequencies in 3' UTR were 28%, 55%, and 16%, respectively. Twenty-one recipients experienced allograft dysfunction with eGFR <30 mL/min/1.73 m2; 10 had AA genotype of rs1042032 polymorphism (chi-square test; A/A vs A/G+G/G; P = .04). Recipients without rs1042032 polymorphism variant allele showed a significant risk for allograft dysfunction (A/A vs A/G+G/G; P = .04; odds ratio, 2.65; 95% confidence interval [CI], 1.03-6.81). Multivariate analysis of the characteristics of patients using a Cox proportional hazard model showed that the AA genotype of rs1042032 polymorphism was predictive of allograft dysfunction (Hazard Ratio = 3.26; P = .04; 95% CI, 1.08-9.59). CONCLUSION: The present study suggested that the presence of the rs1042032 variant allele in EPHX2 was associated with a protective role for allograft function.
Title: Purification, crystallization and preliminary crystallographic analysis of Est25: a ketoprofen-specific hormone-sensitive lipase Kim S, Joo S, Yoon HC, Ryu Y, Kim KK, Kim TD Ref: Acta Crystallographica Sect F Struct Biol Cryst Commun, 63:579, 2007 : PubMed
Ketoprofen, a nonsteroidal anti-inflammatory drug, inhibits the synthesis of prostaglandin. A novel hydrolase (Est25) with high ketoprofen specificity has previously been identified using a metagenomic library from environmental samples. Recombinant Est25 protein with a histidine tag at the N-terminus was expressed in Escherichia coli and purified in a homogenous form. Est25 was crystallized from 2.4 M sodium malonate pH 7.0 and X-ray diffraction data were collected to 1.49 A using synchrotron radiation. The crystals belong to the monoclinic space group C2, with unit-cell parameters a = 197.8, b = 95.2, c = 99.4 A, beta = 97.1 degrees.
Synthesis of a novel series of DPPIV inhibitors with 1,2,4- and 1,3,4-oxadiazolyl ketone derivatives and its structure-activity relationships are discussed. Compound 18h showed good inhibitory activity against DPPIV and favorable pharmacokinetic properties. In vivo pharmacodynamic efficacy and co-crystal structure of compound 18h with DPPIV is also described.
Title: Identification and characterization of a novel (S)-ketoprofen-specific esterase Yoon S, Kim S, Ryu Y, Kim TD Ref: Int J Biol Macromol, 41:1, 2007 : PubMed
A new (S)-ketoprofen specific esterase (EST-Y29) was identified from a metagenome library from environmental samples, which showed homologies with class C-beta lactamase, penicillin binding protein, and other lipases/esterases. In order to investigate the biochemical and biophysical properties, the recombinant protein was overexpressed, purified to homogeneity, and characterized. This EST-Y29 has high catalytic activity against p-nitrophenyl esters of short fatty acids (C(2) and C(4)) and alpha-naphthyl acetate with activation energy of 30.4 kJ/mol. We have further characterized EST-Y29 using high performance liquid chromatography (HPLC), circular dichroism (CD), dynamic light scattering (DLS) and size exclusion chromatography (SEC).
Title: Protective effects of Glycyrrhiza uralensis Fisch. on the cognitive deficits caused by beta-amyloid peptide 25-35 in young mice Ahn J, Um M, Choi W, Kim S, Ha T Ref: Biogerontology, 7:239, 2006 : PubMed
Amyloid beta protein (Abeta) may be involved in the progression of Alzheimer's disease (AD), by acting as a neurotoxin and eliciting oxidative stress. This study was designed to determine the effects of Glycyrrhiza uralensis Fisch. water extract (GWE) on the cognitive deficits and oxidative stress induced by the administration of Abeta(25-35) in mice. Mice in two of the four animal groups were fed an experimental diet containing either 0.5 or 1% GWE for the entire 6-week experimental period. Control mice and a further experimental group were fed a non-GWE diet. Abeta(25-35) was administered to the three experimental groups by intracerebroventricular (i.c.v.) injection (10 microg/10 microl/mouse) once per week in weeks 5 and 6 of the experimental period. Behavioral changes were assessed using both a passive avoidance (after the injection of Abeta(25-35) in week 5) and the Morris water-maze tests (after the injection of Abeta(25-35) in week 6). Control animals were administered vehicle alone. The prolonged consumption of a diet containing GWE ameliorated the cognitive deficits caused by the i.c.v. injections of Abeta(25-35). Treatment with Abeta(25-35) led to higher concentrations of thiobarbituric acid reactive substances in the brain, and GWE attenuated this response. There was a decrease in catalase activity in the group provided with 1% GWE. Acetylcholinesterase activity was significantly reduced in the brains of all GWE-treated animals compared to that in the non-GWE-fed experimental group. These results suggest that GWE exerts a protective effect against the cognitive impairments often observed in AD, and that in mice this effect is mediated by antioxidant actions against oxidative stress.
Magnaporthe grisea is the most destructive pathogen of rice worldwide and the principal model organism for elucidating the molecular basis of fungal disease of plants. Here, we report the draft sequence of the M. grisea genome. Analysis of the gene set provides an insight into the adaptations required by a fungus to cause disease. The genome encodes a large and diverse set of secreted proteins, including those defined by unusual carbohydrate-binding domains. This fungus also possesses an expanded family of G-protein-coupled receptors, several new virulence-associated genes and large suites of enzymes involved in secondary metabolism. Consistent with a role in fungal pathogenesis, the expression of several of these genes is upregulated during the early stages of infection-related development. The M. grisea genome has been subject to invasion and proliferation of active transposable elements, reflecting the clonal nature of this fungus imposed by widespread rice cultivation.
Title: Effects of green tea polyphenol on cognitive and acetylcholinesterase activities Kim HK, Kim M, Kim S, Chung JH Ref: Biosci Biotechnol Biochem, 68:1977, 2004 : PubMed
The effect of tea polyphenol (TP) on cognitive and anti-cholinesterase activity was examined in scopolamine-treated mice. Chronic administration of TP significantly reversed scopolamine-induced retention deficits in both step-through passive avoidance and spontaneous alternation behavior tasks. Furthermore, TP exhibited a dramatic inhibitory effect on acetylcholinesterase activity. This finding suggests that TP might be useful in the treatment of Alzheimer's disease.
Title: Thermostable esterase from a thermoacidophilic archaeon: purification and characterization for enzymatic resolution of a chiral compound Kim S, Lee SB Ref: Biosci Biotechnol Biochem, 68:2289, 2004 : PubMed
Homolog to lipolytic enzymes having the consensus sequence Gly-X-Ser-X-Gly, from the Sulfolobus solfataricus P2 genome, were identified by multiple sequence alignments. Among three potential candidate sequences, one (Est3), which displayed higher activity than the other enzymes on the indicate plates, was characterized. The gene (est 3) was expressed in Escherichia coli, and the recombinant protein (Est3) was purified by chromatographic separation. The enzyme is a trimeric protein and has a molecular weight of 32 kDa in monomer form in its native structure. The optimal pH and temperature of the esterase were 7.4 and 80 degrees C respectively. The enzyme showed broad substrate specificities toward various p-nitrophenyl esters ranging from C2 to C16. The catalytic activity of the Est3 esterase was strongly inhibited by phenylmethylsulfonyl fluoride (PMSF) and diethyl p-nitrophenyl phosphate. Based on substrate specificity and the action of inhibitors, the Est3 enzyme was estimated to be a carboxylesterase (EC 3.1.1.1). The enzyme with methyl (+/-)-2-(3-benzoylphenyl)propionate-hydrolyzing activity to (-)-2-(3-benzoylphenyl)propionic acid displayed a moderate degree of enantioselectivity. The product, (-)-2-(3-benzoylphenyl)propionic acid, rather than its methyl ester, was obtained in 80% enantiomeric excess (e.e.(p)) at 20% conversion at 60 degrees C after a 32-h reaction. This result indicates that S. solfataricus esterase can be used for application in the synthesis of chiral compounds.
Title: Ethanol-response genes and their regulation analyzed by a microarray and comparative genomic approach in the nematode Caenorhabditis elegans Kwon JY, Hong M, Choi MS, Kang S, Duke K, Kim S, Lee S, Lee J Ref: Genomics, 83:600, 2004 : PubMed
The nematode shows responses to acute ethanol exposure that are similar to those observed in humans, mice, and Drosophila, namely hyperactivity followed by uncoordination and sedation. We used in this report the nematode Caenorhabditis elegans as a model system to identify and characterize the genes that are affected by ethanol exposure and to link those genes functionally into an ethanol-induced gene network. By analyzing the expression profiles of all C. elegans ORFs using microarrays, we identified 230 genes affected by ethanol. While the ethanol response of some of the identified genes was significant at early time points, that of the majority was at late time points, indicating that the genes in the latter case might represent the physiological consequence of the ethanol exposure. We further characterized the early response genes that may represent those involved directly in the ethanol response. These genes included many heat shock protein genes, indicating that high concentration of ethanol acts as a strong stress to the animal. Interestingly, we identified two non-heat-shock protein genes that were specifically responsive to ethanol. glr-2 was the only glutamate receptor gene to be induced by ethanol. T28C12.4, which encodes a protein with limited homology to human neuroligin, was also specific to ethanol stress. Finally, by analyzing the promoter regions of the early response genes, we identified a regulatory element, TCTGCGTCTCT, that was necessary for the expression of subsets of ethanol response genes.
Title: Genome-wide cloning and characterization of microbial esterases Ro HS, Hong HP, Kho BH, Kim S, Chung BH Ref: FEMS Microbiology Letters, 233:97, 2004 : PubMed
We have isolated putative esterase genes from various bacterial chromosomes. Thirty open reading frames predicted to encode esterases were randomly selected from 13 sequenced bacterial chromosomes and were cloned into an expression vector. The esterase activity of the resulting clones was tested on a tributyrin plate at different pH values and temperatures. Nine out of thirty tested clones exhibited significant tributyrin hydrolyzing activity. The enzyme S5 from the gene b0494 of Escherichia coli, the enzyme S12 from the gene STM0506 of Salmonella typhimurium, and the enzyme S28 from the gene AF1716 of Archaeoglobus fulgidus exhibited high activity at an alkaline pH range. The esterase S11 encoded by the gene PA3859 of Pseudomonas aeruginosa PAO1 and the esterase S21 from the gene SMc01033 of Sinorhizobium meliloti 1021, both showed a sharp increase in enzyme activity above pH 8.0. Furthermore, the enzymes S5, S12, S21, and S28 retained the esterase activity when they were incubated at 50 degrees C, suggesting that these enzymes are thermostable. Subsequent pH vs. activity and temperature vs. activity experiments with selected enzymes in a solution assay system confirmed the validity of the above data. The genome-wide exploration strategy of proteins provided valuable information on the esterases by revealing subtle biochemical differences between the esterases of different sources.
Title: Identification of a human valacyclovirase: biphenyl hydrolase-like protein as valacyclovir hydrolase Kim I, Chu XY, Kim S, Provoda CJ, Lee KD, Amidon GL Ref: Journal of Biological Chemistry, 278:25348, 2003 : PubMed
Valacyclovir is the 5'-valyl ester prodrug of acyclovir, an effective anti-herpetic drug. Systemic availability of acyclovir in humans is three to five times higher when administered orally as the prodrug. The increased bioavailability of valacyclovir is attributed to carrier-mediated intestinal absorption, via the hPEPT1 peptide transporter, followed by the rapid and complete conversion to acyclovir. The one or more human enzymes responsible for in vivo activation of the prodrug to the active drug and its conversion sites, however, have not been identified. In this report, we describe the purification, identification, and characterization of a human enzyme that activates valacyclovir to acyclovir. A protein with significant hydrolytic activity toward valacyclovir, the 5'-glycyl ester of acyclovir, and the 5'-valyl ester of zidovudine (AZT), was purified from Caco-2 cells derived from human intestine. Using a non-redundant data base search, the N-terminal 19-amino acid sequence of the purified 27-kDa, basic protein revealed a perfect match within the N terminus of a serine hydrolase, Biphenyl hydrolase-like (BPHL, gi:4757862) protein, previously cloned from human breast carcinoma. Recombinant BPHL exhibited significant hydrolytic activity for both valacyclovir and valganciclovir with specificity constants (kcat/Km), 420 and 53.2 mm-1.s-1, respectively. We conclude that BPHL may be an important enzyme activating valacyclovir and valganciclovir in humans and an important new target for prodrug design.
Title: Alternative splicing of the muscarinic acetylcholine receptor GAR-3 in Caenorhabditis elegans Park YS, Kim S, Shin Y, Choi B, Cho NJ Ref: Biochemical & Biophysical Research Communications, 308:961, 2003 : PubMed
Among the three G-protein-linked acetylcholine (ACh) receptors (GAR-1, -2, and -3) in Caenorhabditis elegans (C. elegans), GAR-3 appears most similar to mammalian muscarinic ACh receptors (mAChRs). The gar-3 gene, unlike mammalian mAChR genes, contains introns within the coding region. In this study, we identified an alternatively spliced isoform of GAR-3 (GAR-3a), which differs only in the third intracellular (i3) loop from the previously described one (GAR-3b). GAR-3a has a 26 amino acid insert in the i3 loop compared with GAR-3b. Reverse transcriptase-polymerase chain reaction (RT-PCR) on stage-specific RNAs indicated that both isoforms are expressed at all developmental stages examined, with gar-3b being more abundantly expressed than gar-3a. When these two GAR-3 isoforms were expressed in Chinese hamster ovary (CHO) cells, they exhibited similar ligand binding characteristics. In response to carbachol treatment, the two isoforms stimulated phosphatidylinositol hydrolysis with similar efficacy. Together with our earlier observations that GAR-1 and GAR-2 undergo alternative splicing, this study shows that alternative splicing plays an important role in promoting molecular diversity of G-protein-linked ACh receptors in C. elegans.
The 5.67-megabase genome of the plant pathogen Agrobacterium tumefaciens C58 consists of a circular chromosome, a linear chromosome, and two plasmids. Extensive orthology and nucleotide colinearity between the genomes of A. tumefaciens and the plant symbiont Sinorhizobium meliloti suggest a recent evolutionary divergence. Their similarities include metabolic, transport, and regulatory systems that promote survival in the highly competitive rhizosphere; differences are apparent in their genome structure and virulence gene complement. Availability of the A. tumefaciens sequence will facilitate investigations into the molecular basis of pathogenesis and the evolutionary divergence of pathogenic and symbiotic lifestyles.
Title: Combined pyridostigmine-thyrotrophin-releasing hormone test for the evaluation of hypothalamic somatostatinergic activity in healthy normal men Yang I, Woo J, Kim S, Kim J, Kim Y, Choi Y Ref: European Journal of Endocrinology, 133:457, 1995 : PubMed
Pyridostigmine (PST), a cholinesterase inhibitor, induces a clear growth hormone (GH) release in man by suppression of hypothalamic somatostatin (SRIH). Somatostatin suppresses thyrotrophin (TSH) release in rats and men. Earlier studies showed that the thryotrophin-releasing hormone (TRH)-induced TSH response was not altered by 60-120 mg of PST. We studied whether a larger dose (180 mg) of PST can increase the TSH response to TRH. Six healthy young men were studied with the following six tests: (Test 1) 200 micrograms of TRH i.v.; (Test 2) 180 mg of PST po; (Test 3) three different doses of PST (60, 120, 180 mg) + TRH; (Test 4) 100 micrograms of octreotide (SMS) i.v.; (Test 5) SMS + TRH; (Test 6) PST + SMS + TRH. A large dose of PST (180 mg) significantly augmented GH, TSH and prolactin responses to TRH, while smaller doses of PST (60 and 120 mg) did not significantly increase the responses of GH and TSH. While the increased TRH-induced prolactin response by PST was not suppressed by SMS, the increased responses of GH and TSH were suppressed remarkably by SMS. Most of the subjects noticed a mild to moderate abdominal pain, nausea and muscular fasciculation after the administration of a large dose of PST administration. These data suggest that suppression of hypothalamic SRIH secretion by 180 mg of PST can augment the TSH response to TRH. However, the considerable side effects should be minimized before clinical application of the combined PST-TRH test.
