Feng G

References (21)

Title : Prognostic Value of Serum Cholinesterase Levels for In-Hospital Mortality among Patients with Acute Exacerbation of Chronic Obstructive Pulmonary Disease - Chen_2023_Copd_20_178
Author(s) : Chen Z , Zha L , Feng G , An Q , Shi F , Xu J , Xu Q , Xia H , Zhang M , Li L
Ref : Copd , 20 :178 , 2023
Abstract : Cholinesterase (ChE) is associated with the pathogenesis of chronic obstructive pulmonary disease (COPD), including chronic airway inflammation and oxidation/antioxidant imbalance. However, the relationship between serum ChE levels and survival outcomes of patients hospitalized with acute exacerbations of COPD (AECOPD) is unknown. In this retrospective single-center study, we investigated the ability of the serum ChE level to predict in-hospital death in patients hospitalized with AECOPD. The clinicopathological data, including serum ChE levels as well as clinical and biochemical indicators were extracted for 477 patients from the hospital records and analyzed. Our results demonstrated that AECOPD patients with lower serum ChE levels were associated with increased mortality, frequent hospitalization due to acute exacerbations (AE) in the past year, and longer hospital stay. The optimal cutoff value for the serum ChE level was 4323 U/L. The area under the ROC curve (AUC) values for predicting in-hospital mortality based on the serum ChE level was 0.79 (95% confidence interval (CI), 0.72-0.85). Multivariate logistic regression analysis demonstrated that serum ChE level >= 4323 U/L (odds ratio (OR) 9.09, 95% CI 3.43-28.3, p < 0.001), age-adjusted Charlson comorbidity index (aCCI), and the number of hospitalizations due to AE in the past year were independent risk factors for predicting the in-hospital mortality of AECOPD patients. In conclusion, our study demonstrated that low serum ChE levels were associated with significantly higher in-hospital mortality rates of patients hospitalized with AECOPD. Therefore, serum ChE level is a promising prognostic predictor of hospitalized AECOPD patients.
ESTHER : Chen_2023_Copd_20_178
PubMedSearch : Chen_2023_Copd_20_178
PubMedID: 38178805

Title : Nanozyme-based dual-signal sensing system for colorimetric and photothermal detection of AChE activity in the blood of liver-injured mice - He_2023_Anal.Bioanal.Chem__
Author(s) : He C , Ke Z , Liu K , Peng J , Yang Q , Wang L , Feng G , Fang J
Ref : Anal Bioanal Chem , : , 2023
Abstract : Acetylcholinesterase (AChE), a crucial enzyme related to liver function, is involved in numerous physiological processes such as neurotransmission and muscular contraction. The currently reported techniques for detecting AChE mainly rely on a single signal output, limiting their high-accuracy quantification. The few reported dual-signal assays are challenging to implement in dual-signal point-of-care testing (POCT) because of the need for large instruments, costly modifications, and trained operators. Herein, we report a colorimetric and photothermal dual-signal POCT sensing platform based on CeO(2)-TMB (3,3',5,5'-tetramethylbenzidine) for the visualization of AChE activity in liver-injured mice. The method compensates for the false positives of a single signal and realizes the rapid, low-cost portable detection of AChE. More importantly, the CeO(2)-TMB sensing platform enables the diagnosis of liver injury and provides an effective tool for studying liver disease in basic medicine and clinical applications. Rapid colorimetric and photothermal biosensor for sensitive detection of acetylcholinesterase (I) and acetylcholinesterase levels in mouse serum (II).
ESTHER : He_2023_Anal.Bioanal.Chem__
PubMedSearch : He_2023_Anal.Bioanal.Chem__
PubMedID: 36995409

Title : Characterization of pectin methylesterase gene family and its possible role in juice sac granulation in navel orange (Citrus sinensis Osbeck) - Li_2022_BMC.Genomics_23_185
Author(s) : Li Z , Wu L , Wang C , Wang Y , He L , Wang Z , Ma X , Bai F , Feng G , Liu J , Jiang Y , Song F
Ref : BMC Genomics , 23 :185 , 2022
Abstract : BACKGROUND: Citrus is one of the most important fresh fruit crops worldwide. Juice sac granulation is a physiological disorder, which leads to a reduction in soluble solid concentration, total sugar, and titratable acidity of citrus fruits. Pectin methylesterase (PME) catalyzes the de-methylesterification of homogalacturonans and plays crucial roles in cell wall modification during plant development and fruit ripening. Although PME family has been well investigated in various model plants, little is known regarding the evolutionary property and biological function of PME family genes in citrus. RESULTS: In this study, 53 non-redundant PME genes were identified from Citrus sinensis genome, and these PME genes were divided into four clades based on the phylogenetic relationship. Subsequently, bioinformatics analyses of gene structure, conserved domain, chromosome localization, gene duplication, and collinearity were performed on CsPME genes, providing important clues for further research on the functions of CsPME genes. The expression profiles of CsPME genes in response to juice sac granulation and low-temperature stress revealed that CsPME genes were involved in the low temperature-induced juice sac granulation in navel orange fruits. Subcellular localization analysis suggested that CsPME genes were localized on the apoplast, endoplasmic reticulum, plasma membrane, and vacuole membrane. Moreover, yeast one-hybrid screening and dual luciferase activity assay revealed that the transcription factor CsRVE1 directly bound to the promoter of CsPME3 and activated its activity. CONCLUSION: In summary, this study conducts a comprehensive analysis of the PME gene family in citrus, and provides a novel insight into the biological functions and regulation patterns of CsPME genes during juice sac granulation of citrus.
ESTHER : Li_2022_BMC.Genomics_23_185
PubMedSearch : Li_2022_BMC.Genomics_23_185
PubMedID: 35249536

Title : Immobilized angiotensin II type I receptor: A powerful method of high throughput screening for antihypertensive compound identification through binding interaction analysis - Liang_2020_J.Chromatogr.A__461003
Author(s) : Liang Q , Fu X , Zhang J , Hao J , Feng G , Wang J , Li Q , Ahmad F , Zhao X
Ref : Journal of Chromatography A , :461003 , 2020
Abstract : The enormous growth in drug discovery paradigm has necessitated continuous exploration of new methods for drug-protein interaction analysis. To enhance the role of these methodologies in designing rational drugs, this work extended an immobilized angiotensin II type I receptor (AT1R) based affinity chromatography in antihypertensive compound identification. We fused haloalkane dehalogenase at C-terminus of AT1R and expressed the fusion receptor in E. coli. The expressed receptor was covalently immobilized onto 8.0mum microspheres by mixing the cell lysate with 6-chlorocaproic acid-modified amino polystyrene microspheres. The immobilized AT1R was utilized for thermodynamic and kinetic interaction analysis between the receptor and four specific ligands. Following confirmation of these interactions by molecular docking, we identified puerarin and rosmarinic acid by determining their binding to the receptor. Azilsartan, candesartan, valsartan and olmesartan displayed two kinds of binding sites to AT1R by injection amount-dependent method. By molecular docking, we recognize the driving forces of the interaction as electrostatic interaction, hydrogen bonds and van der Waals force. The dissociation rate constants (kd) of azilsartan, candesartan, valsartan and olmesartan to AT1R were 0.01138 +/- 0.003, 0.05142 +/- 0.003, 0.07547 +/- 0.004 and 0.01310 +/- 0.005 min(-1) by peak profiling assay. Comparing with these parameters, puerarin and rosmarinic acid presented lower affinity (KA: 0.12x10(4) and 1.5x10(4)/M) and slower kinetics (kd: 0.6864 +/- 0.03 and 0.3005 +/- 0.01 min(-1)) to the receptor. These results, taking together, indicated that the immobilized AT1R has the capacity to probe antihypertensive compounds.
ESTHER : Liang_2020_J.Chromatogr.A__461003
PubMedSearch : Liang_2020_J.Chromatogr.A__461003
PubMedID: 32156458

Title : Gamma Oscillation Dysfunction in mPFC Leads to Social Deficits in Neuroligin 3 R451C Knockin Mice - Cao_2018_Neuron_97_1253
Author(s) : Cao W , Lin S , Xia QQ , Du YL , Yang Q , Zhang MY , Lu YQ , Xu J , Duan SM , Xia J , Feng G , Luo JH
Ref : Neuron , 97 :1253 , 2018
Abstract : Neuroligins (NLs) are critical for synapse formation and function. NL3 R451C is an autism-associated mutation. NL3 R451C knockin (KI) mice exhibit autistic behavioral abnormalities, including social novelty deficits. However, neither the brain regions involved in social novelty nor the underlying mechanisms are clearly understood. Here, we found decreased excitability of fast-spiking interneurons and dysfunction of gamma oscillation in the medial prefrontal cortex (mPFC), which contributed to the social novelty deficit in the KI mice. Neuronal firing rates and phase-coding abnormalities were also detected in the KI mice during social interactions. Interestingly, optogenetic stimulation of parvalbumin interneurons in the mPFC at 40 Hz nested at 8 Hz positively modulated the social behaviors of mice and rescued the social novelty deficit in the KI mice. Our findings suggest that gamma oscillation dysfunction in the mPFC leads to social deficits in autism, and manipulating mPFC PV interneurons may reverse the deficits in adulthood.
ESTHER : Cao_2018_Neuron_97_1253
PubMedSearch : Cao_2018_Neuron_97_1253
PubMedID: 29503190
Gene_locus related to this paper: mouse-3neur

Title : Effects of soil acidification on the toxicity of organophosphorus pesticide on Eisenia fetida and its mechanism - Zou_2018_J.Hazard.Mater_359_365
Author(s) : Zou X , Xiao X , Zhou H , Chen F , Zeng J , Wang W , Feng G , Huang X
Ref : J Hazard Mater , 359 :365 , 2018
Abstract : Organophosphorus pesticides (OPs) have been widely used to control agricultural insects. Soil acidification is a major problem in soil of intensive agricultural systems, especially in red soil with a low pH buffer capacity. However, the effects of soil acidification on the toxicity of pesticides are still unclear. In the present study, the toxicity of three OPs on E. fetida was determined at individual (14-day lethal test) and biochemical levels (antioxidative defence enzymes) by using acidified soils (pH=5.5, 4.3 and 3.1). The results showed that the toxicity of tested OPs was slightly increased with the decrease of soil pH. To interpret the phenomena, an optimum Quantitative Structure Activity Relationship (QSAR) model was developed based on the toxicity mechanism and the partial least squares regression (PLS) method. The model indicated bioavailability and toxicodynamics are key factors of soil acidification affecting the toxicity of the OPs. Further results revealed the bioavailability of the OPs was strongly related to their hydrolysis and biodegradation character, whereas the effects of soil acidification on toxicodynamics were mainly caused by the interaction between the acetylcholinesterase (AchE) and the OPs. Results will increase understanding of the effects of soil acidification on the toxicity of pesticides and its mechanism.
ESTHER : Zou_2018_J.Hazard.Mater_359_365
PubMedSearch : Zou_2018_J.Hazard.Mater_359_365
PubMedID: 30048951

Title : Crystal Structure of StnA for the Biosynthesis of Antitumor Drug Streptonigrin Reveals a Unique Substrate Binding Mode - Qian_2017_Sci.Rep_7_40254
Author(s) : Qian T , Wo J , Zhang Y , Song Q , Feng G , Luo R , Lin S , Wu G , Chen HF
Ref : Sci Rep , 7 :40254 , 2017
Abstract : Streptonigrin methylesterase A (StnA) is one of the tailoring enzymes that modify the aminoquinone skeleton in the biosynthesis pathway of Streptomyces species. Although StnA has no significant sequence homology with the reported alpha/beta-fold hydrolases, it shows typical hydrolytic activity in vivo and in vitro. In order to reveal its functional characteristics, the crystal structures of the selenomethionine substituted StnA (SeMet-StnA) and the complex (S185A mutant) with its substrate were resolved to the resolution of 2.71 A and 2.90 A, respectively. The overall structure of StnA can be described as an alpha-helix cap domain on top of a common alpha/beta hydrolase domain. The substrate methyl ester of 10'-demethoxystreptonigrin binds in a hydrophobic pocket that mainly consists of cap domain residues and is close to the catalytic triad Ser185-His349-Asp308. The transition state is stabilized by an oxyanion hole formed by the backbone amides of Ala102 and Leu186. The substrate binding appears to be dominated by interactions with several specific hydrophobic contacts and hydrogen bonds in the cap domain. The molecular dynamics simulation and site-directed mutagenesis confirmed the important roles of the key interacting residues in the cap domain. Structural alignment and phylogenetic tree analysis indicate that StnA represents a new subfamily of lipolytic enzymes with the specific binding pocket located at the cap domain instead of the interface between the two domains.
ESTHER : Qian_2017_Sci.Rep_7_40254
PubMedSearch : Qian_2017_Sci.Rep_7_40254
PubMedID: 28074848
Gene_locus related to this paper: 9actn-l7pij2

Title : The effects of gestational and lactational exposure to Nonylphenol on c-jun, and c-fos expression and learning and memory in hippocampus of male F1 rat - Jie_2017_Iran.J.Basic.Med.Sci_20_386
Author(s) : Jie Y , Pan W , Wenxia Y , Feng G , Liting H , Wenmei L , Jie X
Ref : Iran J Basic Med Sci , 20 :386 , 2017
Abstract : OBJECTIVES: To investigate the effects of Nonylphenol (NP) in pups from dams exposed during gestational and lactational periods on immediate early genes (c-jun, c-fos) in hippocampus and the learning and memory of F1 rats. MATERIALS AND
METHODS: Twenty eight pregnant dams, stratified by pregnancy date, were randomly assigned into 4 groups, which were gavaged with NP at the doses of 50 mg/kg/day, 100 mg/kg/day, 200 mg/kg/day and groundnut oil, respectively. Step-down avoidance test, and learning and memory effects of NP were evaluated on 8-weeks-old pups. The expressions of c-jun and c-fos and the activities of choline acetyltransferase (ChAT) and acetylcholinesterase (AchE) were evaluated in hippocampus of pups.
RESULTS: Compared to the control, reaction time (RT) that pups spent to jump to the platform was longer (P=0.02), the number of errors were higher (P=0.01), and the step-down latency was shorter in the 200 mg/kg/day NP-treated group (P=0.04). Exposure to NP induced a significant reduction in ChAT activity in hippocampus in the 100 (P=0.005) and 200 mg/kg/day NP-treated groups (P=0.002), whereas exposure to 200 mg/kg/day caused a significant increase in AchE activity (P=0.004); a dose-response relationship was revealed between ChAT and AchE activities and NP exposure in the hippocampus of pups (r=-0.821, P=0.01; r=0.757, P=0.04). Exposure to NP in the 100 and 200 mg/kg/day NP-treated groups exhibited an increase in number of c-fos and c-jun positive cells. CONCLUSION: Exposure to NP might negatively affect learning and memory ability in F1 rats, possibly due to the alterations in the expression of c-jun and c-fos, and ChAT, AchE activities in hippocampus of pups.
ESTHER : Jie_2017_Iran.J.Basic.Med.Sci_20_386
PubMedSearch : Jie_2017_Iran.J.Basic.Med.Sci_20_386
PubMedID: 29026496

Title : Relationship of paraoxonase-1 Q192R genotypes and in-stent restenosis and re-stenting in Chinese patients after coronary stenting - Ma_2016_Atherosclerosis_251_305
Author(s) : Ma W , Liang Y , Zhu J , Chen T , Feng G , Yang Y , Liu X , Wang X
Ref : Atherosclerosis , 251 :305 , 2016
Abstract : BACKGROUND AND AIMS: Asians have very different genotype distributions of cytochrome P450 2C19 (CYP2C19), ATP-binding cassette, sub-family B, member 1 (ABCB1), and paraoxonase-1 (PON1), in whom relevant studies based on large samples are scarce. The purpose of this study was to evaluate the effects of these genes on outcomes of in-stent restenosis and re-stenting in Chinese patients after coronary stenting.
METHODS: A total of 2569 acute coronary syndrome (ACS) patients were enrolled in a gene database study. Among the 1674 patients receiving coronary stenting, 504 patients performed repeated coronary angiography within the next year after discharge and were eligible to complete our final cohort.
RESULTS: The prevalence of the CYP2C19 loss-of-function carriers (had at least 1 allele of *2, *3 and *4) was considerable high (52.2%). During re-angiography, in-stent restenosis occurred in 106 (21.0%) out of the 504 patients; the mean restenosis degree was 71.3% and 152 (30.2%) patients received re-stenting treatment. In multivariate regression, only age and left ventricular ejection fraction (LVEF) were significantly associated with in-stent restenosis. As for predictors of re-stenting, multivariate regression identified variables of LVEF, coronary artery lesions, and PON1 Q192R genotype. Genotype RR of PON1 Q192R was an independent risk factor predicting re-stenting compared with genotypes of QQ and QR (OR 1.95, 95% CI 1.30-2.93, p = 0.001). The genotypes of CYP2C19, ABCB1 C3435T, and PON1 L55M showed no significant associations with in-stent restenosis or re-stenting.
CONCLUSIONS: Genotype RR of PON1 Q192R was an independent risk factor predicting re-stenting in Chinese ACS patients after coronary stenting.
ESTHER : Ma_2016_Atherosclerosis_251_305
PubMedSearch : Ma_2016_Atherosclerosis_251_305
PubMedID: 27450784

Title : Draft Genome Sequences of Marinobacter similis A3d10T and Marinobacter salarius R9SW1T - Ivanova_2014_Genome.Announc_2_e00442
Author(s) : Ivanova EP , Ng HJ , Webb HK , Feng G , Oshima K , Hattori M , Ohkuma M , Sergeev AF , Mikhailov VV , Crawford RJ , Sawabe T
Ref : Genome Announc , 2 : , 2014
Abstract : Here, we present the draft genomes of Marinobacter similis A3d10(T), a potential plastic biodegrader, and Marinobacter salarius R9SW1(T), isolated from radioactive waters. This genomic information will contribute information on the genetic basis of the metabolic pathways for the degradation of both plastic and radionuclides.
ESTHER : Ivanova_2014_Genome.Announc_2_e00442
PubMedSearch : Ivanova_2014_Genome.Announc_2_e00442
PubMedID: 24855296
Gene_locus related to this paper: 9alte-a6f367

Title : ChAT-ChR2-EYFP Mice Have Enhanced Motor Endurance But Show Deficits in Attention and Several Additional Cognitive Domains - Kolisnyk_2013_J.Neurosci_33_10427
Author(s) : Kolisnyk B , Guzman MS , Raulic S , Fan J , Magalhaes AC , Feng G , Gros R , Prado VF , Prado MAM
Ref : Journal of Neuroscience , 33 :10427 , 2013
Abstract : Acetylcholine (ACh) is an important neuromodulator in the nervous system implicated in many forms of cognitive and motor processing. Recent studies have used bacterial artificial chromosome (BAC) transgenic mice expressing channelrhodopsin-2 (ChR2) protein under the control of the choline acetyltransferase (ChAT) promoter (ChAT-ChR2-EYFP) to dissect cholinergic circuit connectivity and function using optogenetic approaches. We report that a mouse line used for this purpose also carries several copies of the vesicular acetylcholine transporter gene (VAChT), which leads to overexpression of functional VAChT and consequently increased cholinergic tone. We demonstrate that these mice have marked improvement in motor endurance. However, they also present severe cognitive deficits, including attention deficits and dysfunction in working memory and spatial memory. These results suggest that increased VAChT expression may disrupt critical steps in information processing. Our studies demonstrate that ChAT-ChR2-EYFP mice show altered cholinergic tone that fundamentally differentiates them from wild-type mice.
ESTHER : Kolisnyk_2013_J.Neurosci_33_10427
PubMedSearch : Kolisnyk_2013_J.Neurosci_33_10427
PubMedID: 23785154

Title : Monoacylglycerol lipase is a therapeutic target for Alzheimer's disease - Chen_2012_Cell.Rep_2_1329
Author(s) : Chen R , Zhang J , Wu Y , Wang D , Feng G , Tang YP , Teng Z , Chen C
Ref : Cell Rep , 2 :1329 , 2012
Abstract : Alzheimer's disease (AD) is the most common cause of dementia among older people. There are no effective medications currently available to prevent and treat AD and halt disease progression. Monoacylglycerol lipase (MAGL) is the primary enzyme metabolizing the endocannabinoid 2-arachidonoylglycerol in the brain. We show here that inactivation of MAGL robustly suppressed production and accumulation of beta-amyloid (Abeta) associated with reduced expression of beta-site amyloid precursor protein cleaving enzyme 1 (BACE1) in a mouse model of AD. MAGL inhibition also prevented neuroinflammation, decreased neurodegeneration, maintained integrity of hippocampal synaptic structure and function, and improved long-term synaptic plasticity, spatial learning, and memory in AD animals. Although the molecular mechanisms underlying the beneficial effects produced by MAGL inhibition remain to be determined, our results suggest that MAGL, which regulates endocannabinoid and prostaglandin signaling, contributes to pathogenesis and neuropathology of AD, and thus is a promising therapeutic target for the prevention and treatment of AD.
ESTHER : Chen_2012_Cell.Rep_2_1329
PubMedSearch : Chen_2012_Cell.Rep_2_1329
PubMedID: 23122958

Title : Cell type-specific channelrhodopsin-2 transgenic mice for optogenetic dissection of neural circuitry function - Zhao_2011_Nat.Methods_8_745
Author(s) : Zhao S , Ting JT , Atallah HE , Qiu L , Tan J , Gloss B , Augustine GJ , Deisseroth K , Luo M , Graybiel AM , Feng G
Ref : Nat Methods , 8 :745 , 2011
Abstract : Optogenetic methods have emerged as powerful tools for dissecting neural circuit connectivity, function and dysfunction. We used a bacterial artificial chromosome (BAC) transgenic strategy to express the H134R variant of channelrhodopsin-2, ChR2(H134R), under the control of cell type-specific promoter elements. We performed an extensive functional characterization of the newly established VGAT-ChR2(H134R)-EYFP, ChAT-ChR2(H134R)-EYFP, Tph2-ChR2(H134R)-EYFP and Pvalb(H134R)-ChR2-EYFP BAC transgenic mouse lines and demonstrate the utility of these lines for precisely controlling action-potential firing of GABAergic, cholinergic, serotonergic and parvalbumin-expressing neuron subsets using blue light. This resource of cell type-specific ChR2(H134R) mouse lines will facilitate the precise mapping of neuronal connectivity and the dissection of the neural basis of behavior.
ESTHER : Zhao_2011_Nat.Methods_8_745
PubMedSearch : Zhao_2011_Nat.Methods_8_745
PubMedID: 21985008

Title : The MDGA1 gene confers risk to schizophrenia and bipolar disorder - Li_2011_Schizophr.Res_125_194
Author(s) : Li J , Liu J , Feng G , Li T , Zhao Q , Li Y , Hu Z , Zheng L , Zeng Z , He L , Wang T , Shi Y
Ref : Schizophr Res , 125 :194 , 2011
Abstract : OBJECTIVE: The structural, cytoarchitectural and functional brain abnormalities reported in patients with mental disorders may be due to aberrant neuronal migration influenced by cell adhesion molecules. MDGA1, like Ig-containing cell adhesion molecules, has several cell adhesion molecule-like domains. Moreover, Kahler et al. (2008) reported that the MDGA1 gene was a schizophrenia susceptibility gene in Scandinavian population. To further investigate whether the MDGA1 gene is a shared risk factor of schizophrenia, bipolar disorder and major depressive disorder in Chinese Han population, we conducted this study.
METHODS: We recruited 1135 unrelated schizophrenia patients, 1135 unrelated bipolar disorder patients, 1135 unrelated major depressive disorder patients and 1135 unrelated controls of Chinese Han origin. A total of eleven common SNPs were genotyped using TaqMan(R) technology.
RESULTS: The genotype frequency of rs11759115 differed significantly between schizophrenia patients and controls. The C-C haplotype of rs11759115-rs7769372 was also positively associated with schizophrenia (permutated p=0.046). Rs1883901 was found to be positively associated with bipolar disorder (allele: permutated p=0.0085; genotype: permutated p=0.0009; OR=1.31 [95%CI=1.12-1.52]). The A-G-G haplotype of rs1883901-rs10807187-rs9462343 was also positively associated with bipolar disorder with a global p value of 0.0391 after permutations. No individual SNP or haplotype was associated with major depressive disorder after permutations. CONCLUSION: The MDGA1 gene may confer risk to schizophrenia and bipolar disorder in Chinese Han population.
ESTHER : Li_2011_Schizophr.Res_125_194
PubMedSearch : Li_2011_Schizophr.Res_125_194
PubMedID: 21146959

Title : Improvement in extraction and catalytic activity of Mucor javanicus lipase by modification of AOT reverse micelle - Talukder_2007_Biotechnol.J_2_1369
Author(s) : Talukder MR , Susanto D , Feng G , Wu J , Choi WJ , Chow Y
Ref : Biotechnol J , 2 :1369 , 2007
Abstract : Reverse micelles are formed in apolar solvents by spontaneous aggregation of surfactants. Surfactant sodium bis (2-ethylhexyl) sulfosuccinate (AOT) is most often used for the reverse micellar extraction of enzymes. However, the inactivation of enzyme due to strong interaction with AOT molecules is a severe problem. To overcome this problem, the AOT/water/isooctane reverse micellar system was modified by adding short chain polyethylene glycol 400 (PEG 400). The modified AOT reverse micellar system was used to extract Mucor javanicus lipase from the aqueous phase to the reverse micellar phase. The extraction efficiency (E) increased with the increase in PEG 400 addition and the maximum E in PEG 400 modified system was twofold higher than that in the PEG 400-free system. Upon addition of PEG 400, the water activity (a(w)) of aqueous phase decreased, whereas a(w) of reverse micellar phase increased. The circular dichroism spectroscopy analysis revealed that PEG 400 changes the secondary and tertiary structure of lipase. The maximum specific activity of lipase extracted in PEG 400-modified reverse micellar system was threefold higher than that in the PEG-free system.
ESTHER : Talukder_2007_Biotechnol.J_2_1369
PubMedSearch : Talukder_2007_Biotechnol.J_2_1369
PubMedID: 17639532

Title : Comment on Reelin promotes peripheral synapse elimination and maturation -
Author(s) : Bidoia C , Misgeld T , Weinzierl E , Buffelli M , Feng G , Cangiano A , Lichtman JW , Sanes JR
Ref : Science , 303 :1977\; author reply 1977 , 2004
PubMedID: 15044788

Title : Genetic evidence that relative synaptic efficacy biases the outcome of synaptic competition - Buffelli_2003_Nature_424_430
Author(s) : Buffelli M , Burgess RW , Feng G , Lobe CG , Lichtman JW , Sanes JR
Ref : Nature , 424 :430 , 2003
Abstract : Synaptic activity drives synaptic rearrangement in the vertebrate nervous system; indeed, this appears to be a main way in which experience shapes neural connectivity. One rearrangement that occurs in many parts of the nervous system during early postnatal life is a competitive process called 'synapse elimination'. At the neuromuscular junction, where synapse elimination has been analysed in detail, muscle fibres are initially innervated by multiple axons, then all but one are withdrawn and the 'winner' enlarges. In support of the idea that synapse elimination is activity dependent, it is slowed or speeded when total neuromuscular activity is decreased or increased, respectively. However, most hypotheses about synaptic rearrangement postulate that change depends less on total activity than on the relative activity of the competitors. Intuitively, it seems that the input best able to excite its postsynaptic target would be most likely to win the competition, but some theories and results make other predictions. Here we use a genetic method to selectively inhibit neurotransmission from one of two inputs to a single target cell. We show that more powerful inputs are strongly favoured competitors during synapse elimination.
ESTHER : Buffelli_2003_Nature_424_430
PubMedSearch : Buffelli_2003_Nature_424_430
PubMedID: 12879071

Title : Genetic Analysis of Collagen Q: Roles in Acetylcholinesterase and Butyrylcholinesterase Assembly and in Synaptic Structure and Function - Feng_1999_J.Cell.Biol_144_1349
Author(s) : Feng G , Krejci E , Molgo J , Cunningham JM , Massoulie J , Sanes JR
Ref : Journal of Cell Biology , 144 :1349 , 1999
Abstract : Acetylcholinesterase (AChE) occurs in both asymmetric forms, covalently associated with a collagenous subunit called Q (ColQ), and globular forms that may be either soluble or membrane associated. At the skeletal neuromuscular junction, asymmetric AChE is anchored to the basal lamina of the synaptic cleft, where it hydrolyzes acetylcholine to terminate synaptic transmission. AChE has also been hypothesized to play developmental roles in the nervous system, and ColQ is also expressed in some AChE-poor tissues. To seek roles of ColQ and AChE at synapses and elsewhere, we generated ColQ-deficient mutant mice. ColQ-/- mice completely lacked asymmetric AChE in skeletal and cardiac muscles and brain; they also lacked asymmetric forms of the AChE homologue, butyrylcholinesterase. Thus, products of the ColQ gene are required for assembly of all detectable asymmetric AChE and butyrylcholinesterase. Surprisingly, globular AChE tetramers were also absent from neonatal ColQ-/- muscles, suggesting a role for the ColQ gene in assembly or stabilization of AChE forms that do not themselves contain a collagenous subunit. Histochemical, immunohistochemical, toxicological, and electrophysiological assays all indicated absence of AChE at ColQ-/- neuromuscular junctions. Nonetheless, neuromuscular function was initially robust, demonstrating that AChE and ColQ do not play obligatory roles in early phases of synaptogenesis. Moreover, because acute inhibition of synaptic AChE is fatal to normal animals, there must be compensatory mechanisms in the mutant that allow the synapse to function in the chronic absence of AChE. One structural mechanism appears to be a partial ensheathment of nerve terminals by Schwann cells. Compensation was incomplete, however, as animals lacking ColQ and synaptic AChE failed to thrive and most died before they reached maturity.
ESTHER : Feng_1999_J.Cell.Biol_144_1349
PubMedSearch : Feng_1999_J.Cell.Biol_144_1349
PubMedID: 10087275

Title : Rapsyn clusters neuronal acetylcholine receptors but is inessential for formation of an interneuronal cholinergic synapse - Feng_1998_J.Neurosci_18_4166
Author(s) : Feng G , Steinbach JH , Sanes JR
Ref : Journal of Neuroscience , 18 :4166 , 1998
Abstract : Nicotinic acetylcholine receptors (AChRs) are clustered at high density in the postsynaptic membranes of skeletal neuromuscular junctions and cholinergic interneuronal synapses. A cytoplasmic protein, rapsyn, is essential for AChR clustering in muscle. Here, we asked whether rapsyn mediates neuronal AChR clustering at cholinergic synapses in a mammalian sympathetic ganglion, the superior cervical ganglion (SCG). Several observations supported this possibility: (1) AChR clusters containing the alpha3-5 and beta2 subunits, homologs of the muscle AChR subunits, are present at SCG synapses; (2) rapsyn RNA is readily detectable in the SCG; and (3) expression of recombinant rapsyn in heterologous cells induces aggregation of coexpressed neuronal AChR subunits. However, rapsyn protein was undetectable at ganglionic synaptic sites. Moreover, aggregates of neuronal AChRs induced in heterologous cells by full-length rapsyn remained intracellular, whereas rapsyn-induced clusters of muscle AChRs reached the cell surface. Additional studies revealed a second rapsyn RNA species in SCG generated by alternative splicing and competent to encode a novel short rapsyn isoform. However, this isoform clustered neither neuronal nor muscle AChRs in heterologous cells. Most telling, the number, size, and density of AChR clusters in SCG did not differ significantly between neonatal mice bearing a targeted mutation of the rapsyn gene and littermate controls. Thus, rapsyn is dispensable for clustering of ganglionic neuronal nicotinic AChRs.
ESTHER : Feng_1998_J.Neurosci_18_4166
PubMedSearch : Feng_1998_J.Neurosci_18_4166
PubMedID: 9592096

Title : Development of the neuromuscular junction: genetic analysis in mice - Sanes_1998_J.Physiol.Paris_92_167
Author(s) : Sanes JR , Apel ED , Burgess RW , Emerson RB , Feng G , Gautam M , Glass D , Grady RM , Krejci E , Lichtman JW , Lu JT , Massoulie J , Miner JH , Moscoso LM , Nguyen Q , Nichol M , Noakes PG , Patton BL , Son YJ , Yancopoulos GD , Zhou H
Ref : Journal de Physiologie (Paris) , 92 :167 , 1998
Abstract : Formation of the skeletal neuromuscular junction is a multi-step process that requires communication between the nerve and muscle. Studies in many laboratories have led to identification of factors that seem likely to mediate these interactions. 'Knock-out' mice have now been generated with mutations in several genes that encode candidate transsynaptic messengers and components of their effector mechanisms. Using these mice, it is possible to test hypotheses about the control of synaptogenesis. Here, we review our studies on neuromuscular development in mutant mice lacking agrin alpha CGRP, rapsyn, MuSK, dystrophin, dystrobrevin, utrophin, laminin alpha 5, laminin beta 2, collagen alpha 3 (IV), the acetylcholine receptor epsilon subunit, the collagenous tail of acetylcholinesterase, fibroblast growth factor-5, the neural cell adhesion molecule, and tenascin-C.
ESTHER : Sanes_1998_J.Physiol.Paris_92_167
PubMedSearch : Sanes_1998_J.Physiol.Paris_92_167
PubMedID: 9789802

Title : epsilon-Sarcoglycan, a broadly expressed homologue of the gene mutated in limb-girdle muscular dystrophy 2D - Ettinger_1997_J.Biol.Chem_272_32534
Author(s) : Ettinger AJ , Feng G , Sanes JR
Ref : Journal of Biological Chemistry , 272 :32534 , 1997
Abstract : The sarcoglycans are transmembrane components of the dystrophin-glycoprotein complex, which links the cytoskeleton to the extracellular matrix in adult muscle fibers. Mutations in all four known sarcoglycan genes (alpha, beta, gamma, and delta) have been found in humans with limb-girdle muscular dystrophy. We have identified a novel protein, epsilon-sarcoglycan, that shares 44% amino acid identity with alpha-sarcoglycan (adhalin). We show that epsilon-sarcoglycan is a membrane-associated glycoprotein and document its expression by Northern blotting, immunoblotting, and immunofluorescence. In contrast to alpha-delta sarcoglycans, which are expressed predominantly or exclusively in striated muscle, epsilon-sarcoglycan is broadly distributed in muscle and nonmuscle cells of both embryos and adults. These results raise the possibility that sarcoglycan-containing complexes mediate membrane-matrix interactions in many cell types.
ESTHER : Ettinger_1997_J.Biol.Chem_272_32534
PubMedSearch : Ettinger_1997_J.Biol.Chem_272_32534
PubMedID: 9405466