Title: Atomistic insight into the binding mode and self-regulation mechanism of IsPETase towards PET substrates with different polymerization degrees Chen L, Fan F, Yang M, Wang L, Bai Y, Qiu S, Lyu C, Huang J Ref: Phys Chem Chem Phys, 25:18332, 2023 : PubMed
Poly(ethylene terephthalate) (PET) is one of the most widely used synthetic polyesters, however, its extensive use creates a long-term environmental burden. Unlike traditional recycling methods, biodegradation is a sustainable strategy. The emergence of PETase from Ideonella sakaiensis 201-F6 (IsPETase) has brought great potential for the industrialization of degradable PET. In this work, models of enzyme-substrate complexes with different degrees of polymerization were established to study the binding mode using molecular dynamics simulation. We found that the whole binding site can be further subdivided into three parts, including head, middle and tail binding regions. Most importantly, the presence of the middle region formed by both ends of Ser93 and Ser236 provides a potential possibility for the binding of substrates with different chain lengths, and exerts the self-regulation ability of enzymes to accommodate substrates. Meanwhile, the 'pocket bottom' Arg280 in the tail region echoes the 'pocket mouth' Trp185 in the head region, defining the substrate binding region. This work reveals the self-regulation of IsPETase, as well as the key residues for the substrate binding. The solution to these problems enables us to better understand the function of enzymes and design high-performance degradation enzymes, which is of great significance for industrial application research.
OBJECTIVE: Pro-inflammatory polarization of adipose tissue macrophages (ATMs) plays a critical role in the pathogenesis of obesity-associated chronic inflammation. However, little is known about the role of lipids in the regulation of ATMs polarity and inflammation in response to metabolic stress. Deletion of alpha/beta-hydrolase domain-containing 6 (ABHD6), a monoacylglycerol (MAG) hydrolase, has been shown to protect against diet-induced obesity and insulin resistance. METHODS AND RESULTS: Here we investigated the immunometabolic role of macrophage ABHD6 in response to nutrient excess. Whole-body ABHD6 KO mice on high-fat diet showed lower susceptibility to systemic diet-induced inflammation. Moreover, in the setting of overnutrition, stromal vascular cells from gonadal fat of KO vs. control mice contained lower number of M1 macrophages and exhibited enhanced levels of metabolically activated macrophages (MMe) and M2 markers, oxygen consumption, and interleukin-6 (IL-6) release. Likewise, under in vitro nutri-stress condition, pharmacological inhibition of ABHD6 in MMe-polarized macrophages attenuated the expression and release of pro-inflammatory cytokines and M1 markers and induced the upregulation of lipid metabolism genes. ABHD6-inhibited MMe macrophages showed elevated levels of peroxisome proliferator-activated receptors (PPARs) and 2-MAG species. Notably, among different MAG species, only 2-MAG treatment led to increased levels of PPAR target genes in MMe macrophages. CONCLUSIONS: Collectively, our findings identify ABHD6 as a key component of pro-inflammatory macrophage activation in response to excess nutrition and implicate an endogenous macrophage lipolysis/2-MAG/PPARs cascade, as a lipid signaling and immunometabolic pathway, which favors the anti-inflammatory polarization of ATMs in obesity.
Organophosphate esters (OPEs) are widespread in various environmental media, and can disrupt thyroid endocrine signaling pathways. Mechanisms by which OPEs disrupt thyroid hormone (TH) signal transduction are not fully understood. Here, we present in vivo-in vitro-in silico evidence establishing OPEs as environmental THs competitively entering the brain to inhibit growth of zebrafish via multiple signaling pathways. OPEs can bind to transthyretin (TTR) and thyroxine-binding globulin, thereby affecting the transport of TH in the blood, and to the brain by TTR through the blood-brain barrier. When GH3 cells were exposed to OPEs, cell proliferation was significantly inhibited given that OPEs are competitive inhibitors of TH. Cresyl diphenyl phosphate was shown to be an effective antagonist of TH. Chronic exposure to OPEs significantly inhibited the growth of zebrafish by interfering with thyroperoxidase and thyroglobulin to inhibit TH synthesis. Based on comparisons of modulations of gene expression with the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes databases, signaling pathways related to thyroid endocrine functions, such as receptor-ligand binding and regulation of hormone levels, were identified as being affected by exposure to OPEs. Effects were also associated with the biosynthesis and metabolism of lipids, and neuroactive ligand-receptor interactions. These findings provide a comprehensive understanding of the mechanisms by which OPEs disrupt thyroid pathways in zebrafish.
        
Title: The facile formation of hierarchical mesoporous silica nanocarriers for tumor-selective multimodal theranostics Guo X, Zhu M, Yuan P, Liu T, Tian R, Bai Y, Zhang Y, Chen X Ref: Biomater Sci, :, 2021 : PubMed
The combination of therapeutic and diagnostic functions in a single platform has aroused great interest due to the more optimal synergistic effects that can be obtained as compared to any single theranostic approach alone. However, current nanotheranostics are normally formed via complicated construction steps involving the pre-synthesis of each component and further conjugation via chemical bonds, which may cause low integration efficiency and limit production and applications. Herein, a tumor-targeting and tumor-responsive all-in-one nanoplatform based on mesoporous silica nanocarriers (MSNs) was fabricated via a facile approach utilizing efficient and nondestructive physical interactions for long-wavelength fluorescence imaging-guided synergistic chemo-catalytic-photothermal tumor therapy. The MSNs were endowed with these multimodal theranostics via a simple hydrothermal method after coordinating with Fe2+ and glutathione (GSH) to introduce ferroferric oxide and carbon dots in situ. The former acts as a photothermal agent and catalytic agent to generate local heat under 808 nm irradiation and also when toxic hydroxyl radicals (OH) are in contact with abundant hydrogen peroxide in cancer cells, while the latter participates in fluorescence imaging. After loading with paclitaxel (PTX), polyester and folic-acid-conjugated cyclodextrin were employed to serve as an esterase-sensitive gatekeeper controlling PTX release from the MSN pores and as a tumor-targeting agent for accurate therapy, respectively. As expected, the nanoplatform was efficiently taken up by tumor cells over healthy cells, and then, synergetic chemo-catalytic-photothermal therapy was performed, resulting in 5-fold greater apoptosis of tumor cells as compared to healthy cells under 808 nm irradiation. Moreover, in vivo data from tumor-bearing mouse models showed that tumors were significantly inhibited, and the survival rates of these mice increased to greater than 80% after 5 weeks of treatment with our nanoplatform. These therapeutic processes could be directly tracked via fluorescence imaging enabled by carbon dots and, therefore, our nanoplatform provides a promising theranostics approach for tumor treatment.
        
Title: Elemene Emulsion Injection Administration Reduces Neuropathic Pain by Inhibiting Astrocytic NDRG2 Expression within Spinal Dorsal Horn Ma LT, Bai Y, Li J, Qiao Y, Liu Y, Zheng J Ref: Chin J Integr Med, 27:912, 2021 : PubMed
OBJECTIVE: To investigate the mechanisms underlying elemene-induced analgesia in rats with spared nerve injury (SNI). METHODS: Sixty-five rats were equally divided into 5 groups using a random number table: naive group, sham group, SNI group, SNI + elemene (40 mg.kg(-1).d(-1)) group and naive + elemene (40 mg.kg(-1).d(-1)) group. An SNI rat model was established and the intervention were given respectively for 14 consecutive days. Von Frey filament tests and elevated plus-maze (EPM) tests were used to evaluate the effect of elemene on the mechanical threshold and anxiety, respectively. Immunoblotting and immunostaining were used to measure the expression of glial fibrillary acidic protein (GFAP) and NMYC downstream-regulated gene 2 (NDRG2) within the lumbar spinal dorsal horn (SDH). RESULTS: The SNI rat model exhibited a significant decrease in paw withdrawal threshold and exploratory behaviour in the EPM (P<0.05). Consecutive administration of elemene alleviated SNI-induced mechanical allodynia and anxiety in rats (P<0.05). Immunohistochemical data showed that elemene decreased SNI-induced upregulation of NDRG2 within the SDH (P<0.05). Double immunofluorescent staining data further showed that elemene decreased SNI-induced upregulation of the number of GFAP immunoreactive (-ir), NDRG-ir, and GFAP/NDRG2 double-labelled cells within the SDH (P<0.05). Immunoblotting data showed that elemene decreased SNI-induced upregulation of GFAP and NDRG2 within the SDH (P<0.05). CONCLUSION: Elemene possibly alleviated neuropathic pain by downregulating the expression of NDRG2 in spinal astrocytes in a rat model of SNI.
Epoxide hydrolases catalyze the hydrolysis of both exogenous and endogenous epoxides to the corresponding vicinal diols by adding water. Microsomal and soluble epoxide hydrolase are two main mammalian enzymes that have been intensely characterized. The purpose of this investigation was to develop and validate a proteomics assay allowing the simultaneous quantification of microsomal and soluble epoxide hydrolase in rats. Protein quantification was realized through targeted proteomics, using liquid chromatography with tandem mass spectrometry for the determination of trypsin-specific surrogate peptides after digestion. Stable isotope-labeled peptides were used as the internal standards. The chromatography of the surrogate peptides was performed on an Agilent SB C(18) column (100 mm x 4.6 mm, 1.8 microm) with gradient elution. Acetonitrile containing 0.1% formic acid and 0.1% formic acid aqueous solution were used as mobile phases. A multiple reaction monitoring method in a positive ionization mode was used for the simultaneous detection of the peptides. The method was validated concerning the specificity, linearity, within-day and between-day accuracy and precision, matrix effect, stability, and digestion efficiency. The developed assay was successfully used to quantify the protein levels of microsomal and soluble epoxide hydrolase in rat liver, kidney, and heart S9 samples. This article is protected by copyright. All rights reserved.
        
Title: Isolation, sequencing of the HvnHID gene and its role in the purple-grain colour development in Tibetan hulless barley Yao X, Su L, Yao Y, An L, Bai Y, Li X, Wu K Ref: _Czech J Genet Plant Breed, :, 2021 : PubMed
2-hydroxyisoflavanone dehydratase (HID) plays an important role in isoflavone biosynthesis. In this study, HID was isolated from the seeds of the purple-grained Tibetan hulless barley variety Nerumuzha and the white-grained variety Kunlun 10. The HvnHID gene includes the 981 bp open reading frame and encodes a protein of 327 amino acids. It has a typical Abhydrolase_3 domain (78-306) and belongs to the carboxylesterase (CXE) family of the Abhydrolase_3 (alpha/beta hydrolase) superfamily. There are eight nucleotide differences in the HvnHID coding sequence and two amino acid differences (one in the Abhydrolase_3 domain) between Nerumuzha and Kunlun 10. The HvnHID of hulless barley has the closest relationship with the HID in Hordeum vulgare, and the most distant relationship in Panicum hallii. At the early-mid stage of the seed colour development, the HvnHID expression levels in the purple and black seeds were significantly higher than in the white and blue ones (P < 0.01). During the seed colour development of purple-grained hulless barley, the expression of the key genes (HvnF3'H, HvnDRF, HvnANT1, and HvnGT) in the anthocyanidin biosynthetic pathway increased significantly, while the HvnHID expression decreased significantly (P < 0.01). Thus, it is likely that HvnHID negatively regulates the anthocyanidin biosynthesis. This result provides an important basis for further study of the biological functions of HvnHID in the anthocyanidin biosynthetic pathway.
Hepatocellular carcinoma (HCC) is one of the most common types of cancer, which is associated with a poor prognosis. It is necessary to identify novel prognostic biomarkers and therapeutic targets to improve the survival of patients with HCC. In the present study, a sevengene signature associated with HCC progression was identified using weighted gene coexpression network analysis and least absolute shrinkage and selection operator, and its prognostic prediction value was confirmed in The Cancer Genome Atlasliver HCC and International Cancer Genome Consortium liver cancerRIKEN, Japan cohorts. Subsequently, a rarely reported gene, epoxide hydrolase 2 (EPHX2), was selected for further validation. Downregulation of EPHX2 in HCC was revealed using multiple expression datasets. Furthermore, reduced expression of EPHX2 was confirmed in HCC tissue samples and cell lines using reverse transcriptionquantitative polymerase chain reaction and western blotting. Additionally, KaplanMeier survival curves indicated that patients with higher EPHX2 expression exhibited better prognosis, and clinicopathological analysis also revealed elevated EPHX2 levels in patients with earlystage HCC. Notably, EPHX2 was identified as an independent prognostic biomarker for overall survival of patients with HCC. Gene Ontology analysis, Kyoto Encyclopedia of Genes and Genomes analysis and gene set enrichment analysis were performed to elucidate the functions of EPHX2. The results suggested that EPHX2 expression was closely associated with metabolic reprogramming. Finally, the prognostic value of EPHX2 was evaluated using HCC tissue microarrays. In conclusion, downregulation of EPHX2 was significantly associated with the development of HCC; therefore, EPHX2 may be considered a putative therapeutic candidate for the targeted treatment of HCC.
Alzheimer's disease (AD) is a neurodegenerative disorder characterized by learning and memory impairments. Recent studies have suggested that AD can be induced by multiple factors, such as cholinergic system dysfunction and beta-amyloid (Abeta) neurotoxicity. It was reported that 6-bromo-N-propionyltryptamine could treat neurological diseases, including AD. In the present study, 6-bromotryptamine A, a derivative of 6-bromo-N-propionyltryptamine, was synthesized by the condensation of 2-(6-bromo-1H-indol-3-yl)ethan-1-amine and 2-(4-bromophenyl)acetic acid, and was used as a potential anti-AD molecule. Furthermore, scopolamine can induce impairments of learning and memory, and was widely used to establish AD animal models. The results demonstrated that 6-bromotryptamine A significantly prevented scopolamine-induced short-term cognitive impairments, as revealed by various behavioral tests in mice. Furthermore, an acetylcholinesterase (AChE) activity assay revealed that 6-bromotryptamine A directly inhibited AChE activity. Notably, it was observed that 6-bromotryptamine A blocked the formation of Abeta oligomer, as evaluated by the dot blot assay. All these results suggested that 6-bromotryptamine A may be used to prevent impairments in short-term learning and memory ability possibly via the inhibition of AChE and the blockade of Abeta oligomer formation.
A novel feruloyl esterase (BpFae12) with rosmarinic acid (RA) hydrolysis activity was isolated from Bacillus pumilus W3 and expressed in Escherichia coli BL21 (DE3). With RA as a substrate, the optimal pH and temperature of BpFae12 were pH 8.0 and 50 degreesC, respectively. The specific enzyme activity was 12.8 U.mg(-1). BpFae12 showed the highest activity and substrate affinity toward RA (V(max) of 13.13 U.mg(-1), K(m) of 0.41 mM). Moreover, it also presented strong hydrolysis performance against chlorogenic acid (190.17 U.mg(-1)). RA was effectively Hydrolyzed into more bioactive caffeic acid and 3,4-dihydroxyphenyllactic acid by BpFae12, which have potential applications in the food industry.
        
Title: Per- and polyfluoroalkyl substances exert strong inhibition towards human carboxylesterases Liu YZ, Pan LH, Bai Y, Yang K, Dong PP, Fang ZZ Ref: Environ Pollut, 263:114463, 2020 : PubMed
PFASs are highly persistent in both natural and living environment, and pose a significant risk for wildlife and human beings. The present study was carried out to determine the inhibitory behaviours of fourteen PFASs on metabolic activity of two major isoforms of carboxylesterases (CES). The probe substrates 2-(2-benzoyl-3-methoxyphenyl) benzothiazole (BMBT) for CES1 and fluorescein diacetate (FD) for CES2 were utilized to determine the inhibitory potentials of PFASs on CES in vitro. The results demonstrated that perfluorododecanoic acid (PFDoA), perfluorotetradecanoic acid (PFTA) and perfluorooctadecanoic acid (PFOcDA) strongly inhibited CES1 and CES2. The half inhibition concentration (IC(50)) value of PFDoA, PFTA and PFOcDA for CES1 inhibition was 10.6 microM, 13.4 microM and 12.6 microM, respectively. The IC(50) for the inhibition of PFDoA, PFTA and PFOcDA towards CES2 were calculated to be 9.56 microM, 17.2 microM and 8.73 microM, respectively. PFDoA, PFTA and PFOcDA exhibited noncompetitive inhibition towards both CES1 and CES2. The inhibition kinetics parameters (K(i)) were 27.7 microM, 26.9 microM, 11.9 microM, 4.04 microM, 29.1 microM, 27.4 microM for PFDoA-CES1, PFTA-CES1, PFOcDA-CES1, PFDoA-CES2, PFTA-CES2, PFOcDA-CES2, respectively. In vitro-in vivo extrapolation (IVIVE) predicted that when the plasma concentrations of PFDoA, PFTA and PFOcDA were greater than 2.77 microM, 2.69 microM and 1.19 microM, respectively, it might interfere with the metabolic reaction catalyzed by CES1 in vivo; when the plasma concentrations of PFDoA, PFTA and PFOcDA were greater than 0.40 microM, 2.91 microM, 2.74 microM, it might interfere with the metabolic reaction catalyzed by CES2 in vivo. Molecular docking was used to explore the interactions between PFASs and CES. In conclusion, PFASs were found to cause inhibitory effects on CES in vitro, and this finding would provide an important experimental basis for further in vivo testing of PFASs focused on CES inhibition endpoints.
        
Title: Hydroxylated polychlorinated biphenyls (OH-PCBs) exert strong inhibitory effects towards human carboxylesterases (CESs) Sun HZ, Qin GQ, Wang FG, Bai Y, Zhang Z, Fang ZZ Ref: Sci Total Environ, 745:141140, 2020 : PubMed
Polychlorinated biphenyls (PCBs) have been reported to pose a severe risk towards human health, and hydroxylated polychlorinated biphenyls (OH-PCBs) were potential substances basis for PCBs' toxicity. This study aims to determine the inhibition of OH-PCBs towards human carboxylesterases (CESs), including CES1 and CES2. For phenotypic analysis of CES1 and CES2 activity, we used the hydrolysis metabolism of 2-(2-benzoyl3-methoxyphenyl) benzothiazole (BMBT) and fluorescein diacetate (FD) catalyzed by human liver microsomes (HLMs) as the probe reactions. Preliminary inhibition screening showed that the inhibition potential of OH-PCBs towards CES1 and CES2 increased with the increased numbers of chlorine atoms in OH-PCBs. Both 2'-OH-PCB61 and 2'-OH-PCB65 showed concentration-dependent inhibition towards both CES1 and CES2. Lineweaver-Burk plots showed that 2'-OH-PCB61 and 2'-OH-PCB65 exerted non-competitive inhibition towards CES1 and competitive inhibition towards CES2. The inhibition kinetics parameters (Ki) were 6.8 muM and 7.0 muM for 2'-OH-PCB61 and 2'-OH-PCB65 towards CES1, respectively. The inhibition kinetics parameters (Ki) were 1.4 muM and 1.0 muM for 2'-OH-PCB61 and 2'-OH-PCB65 towards CES2, respectively. In silico docking methods elucidate the contribution of hydrogen bonds and hydrophobic contacts towards the binding of 2'-OH-PCB61 and 2'-OH-PCB65 with CES1 and CES2. All these results will provide a new perspective for elucidation of toxicity mechanism of PCBs and OH-PCBs.
Patatin, the major protein found in potatoes, was purified and shows several isoforms. The essential amino acid content of patatin was ashighas 76%, indicating that it is a valuable protein source. Patatin was an O-linked glycoprotein that contained fucose monosaccharides, as well as mannose, rhamnose, glucose, galactose, xylose, and arabinose. Patatin had a fucosylated glycan structural feature, which strongly bound AAL (Aleuria aurantia Leukoagglutinin), a known fucose binding lectin. Moreover, thelipid metabolism regulatory effects of patatin on the fat catabolism, fat absorption, and inhibition of lipase activity were measured after high-fat feeding of zebrafish larvae. Results revealed that 37.0 g/mL patatin promoted 23% lipid decomposition metabolism. Meanwhile patatin could inhibite lipase activity and fat absorption, whose effects accounted for half that of a positive control drug. Our findings suggest that patatin, a fucosylated glycoprotein, could potentially be used as a naturalactiveconstituent with anti-obesity effects.
        
Title: Biochemical Characterization and Mutational Analysis of a Lactone Hydrolase from Phialophora americana Yu X, Tu T, Luo H, Huang H, Su X, Wang Y, Zhang J, Bai Y, Yao B Ref: Journal of Agricultural and Food Chemistry, 68:2570, 2020 : PubMed
The mycotoxin zearalenone (ZEN) is a secondary metabolite produced mainly by Fusarium species. ZEN poses health hazards both for humans and animals, as a major contaminant in the food and feed industries. Currently, there is no effective technique for degrading ZEN during industrial processes. In this study, we isolated and biochemically characterized a novel lactone hydrolase, ZHD607, isolated from Phialophora americana, cloned, and exogenously expressed in Pichia pastoris. ZHD607 was characterized as a mesophilic lactone hydrolase having a neutral pH and showing optimal activity at 35 degreesC and pH 8.0. Two mutants, ZHDM1 and I160Y, generated from ZHD607 based on structure and sequence alignment analyses, exhibited 2.9- and 3.4-fold higher activity towards ZEN than did ZHD607. Molecular dynamics simulation revealed diverse mechanisms driving this improved catalytic activity. These findings enrich our knowledge about ZHD enzyme family and represent an important step toward industrialization of ZEN-detoxifying lactone hydrolases.
Postoperative cognitive dysfunction (POCD) is a common neurological disease affecting the elderly patients after surgery. Unfortunately, no effective treatment for this disease has been discovered. Edaravone, a clinical-used free radical scavenger, at 3 mg/kg has been reported to prevent neuroinflammation induced by the combination of surgery and lipopolysaccharide in adult rodents. However, we found that edaravone at such low concentration could not inhibit POCD in aged mice. Instead, edaravone at 33.2 mg/kg significantly prevented recognition and spatial cognitive dysfunctions in 14 month aged mice after abdominal surgery under general anesthesia with isoflurane. Furthermore, edaravone significantly prevented the increase of tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta) and interleukin-6 (IL-6) induced by abdominal surgery in aged mice. Edaravone could also decrease glial fibrillary acidic protein (GFAP) and ionized calcium binding adaptor molecule-1 (Iba-1) positive areas in the hippocampal regions of surgery mice, suggesting that edaravone might inhibit surgery-induced over-activation of microglia and astrocytes. Moreover, edaravone substantially increased the expression of PSD-95 and pSer9-glycogen synthase kinase-3beta (pSer9-GSK3beta) as demonstrated by Western blotting assay. Furthermore, the activity of acetylcholinesterase (AChE) is decreased in the mice in edaravone group. All these results suggested that edaravone at high concentrations could inhibit surgery-induced cognitive impairments in aged animals, possibly via the attenuation of neuroinflammation, the increase of synaptic proteins, and the elevation of cholinergic transmission, providing a further support that edaravone might be developed as a treatment of POCD.
        
Title: Expression and characterisation of feruloyl esterases from Lactobacillus fermentum JN248 and release of ferulic acid from wheat bran Deng H, Jia P, Jiang J, Bai Y, Fan TP, Zheng X, Cai Y Ref: Int J Biol Macromol, 138:272, 2019 : PubMed
Genes encoding six feruloyl esterases (FAEs; lbff0997, lbff0272, lbff1432, lbff1695, lbff1849, lbff0153) from Lactobacillus fermentum JN248 were cloned, overexpressed and characterised. Maximum enzyme activity was observed at 35 degrees C for recombinant FAEs LFFae0997, LFFae0272 and LFFae0153, at 30 degrees C for LFFae1695, and at 40 degrees C for LFFae1432and LFFae1849. For five of the enzymes, optimal activity was observed at pH7.0 or pH8.0, and high thermostability was measured up to 55 degrees C. By contrast, LFFae1432 lost less than 10.0% activity after incubation at 40 degrees C for 2h, and pH stability was highest between pH7.0 and pH9.0. In addition, LFFae1432 was the most robust esterase, with a higher affinity and hydrolytic activity against synthetic esters. The enzymes released ferulic acids (FAs) from de-starched wheat bran (DSWB), and 60.7% of the total alkali-extractable FAs were released when LFFae1432 was added alone, compared with less than 10% for the other enzymes. The amount of FAs released by FAEs increased when combined with xylanase. These FAEs could serve as promising biocatalysts for biodegradation, and LFFae1432 may hold promise for potential industrial applications.
        
Title: Neuroprotective effects of matrine on scopolamine-induced amnesia via inhibition of AChE/BuChE and oxidative stress Sun K, Bai Y, Zhao R, Guo Z, Su X, Li P, Yang P Ref: Metabolic Brain Disease, 34:173, 2019 : PubMed
The present study was designed to evaluate the effects of matrine (MAT) on scopolamine (SCOP)-induced learning and memory impairment. After successive oral administration of MAT to mice for three days at doses of 0.4, 2, and 10 mg/kg, we assessed improvements in learning and memory and investigated the mechanism of action of SCOP-induced amnesia. Donepezil at a dose of 3 mg/kg was used as a standard memory enhancer. MAT significantly improved SCOP-induced learning and memory impairment in novel object recognition and Y-maze tests at doses of 0.4, 2, and 10 mg/kg. Furthermore, MAT inhibited acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) activities and decreased oxidative stress in the brain, as evidenced by increased total antioxidant capacity, total superoxide dismutase levels, and catalase activities as well as decreased malondialdehyde levels. Additionally, there was a significant negative correlation between the percentage of spontaneous alternation in the Y maze and AChE activity in the cortex and hippocampus. MAT ameliorated SCOP-induced amnesia by the inhibition of both AChE/BuChE activities and oxidative stress. This study provides further evidence to encourage the development of MAT as a drug for the prevention or treatment of Alzheimer's disease.
The environmental impact of exposure to 3D-printed plastics as well as potential migration of toxic chemicals from 3D-printed plastics remains largely unexplored. In this work we applied leachates from plastics fabricated using a stereolithography (SLA) process to early developmental stages of zebrafish (Danio rerio) to investigate developmental toxicity and neurotoxicity. Migration of unpolymerized photoinitiator, 1-hydroxycyclohexyl phenyl ketone (1-HCHPK) from a plastic solid phase to aqueous media at up to 200 mg/L in the first 24h was detected using gas chromatography-mass spectrometry. Both plastic extracts (LC50 22.25% v/v) and 1-HCHPK (LC50 60mg/L) induced mortality and teratogenicity within 48h of exposure. Developmental toxicity correlated with in situ generation of reactive oxygen species (ROS), an increase in lipid peroxidation and protein carbonylation markers and enhanced activity of superoxide dismutase (SOD) and glutathione-S-transferase (GST) in embryos exposed to concentrations as low as 20% v/v for plastic extracts and 16 mg/L for 1-HCHPK. ROS-induced cellular damage led to induction of caspase-dependent apoptosis which could be pharmacologically inhibited with both antioxidant ascorbic acid and a pan-caspase inhibitor. Neuro-behavioral analysis showed that exposure to plastic leachates reduced spontaneous embryonic movement in 24-36 hpf embryos. Plastic extracts in concentrations above 20% v/v induced rapid retardation of locomotion, changes in photomotor response and habituation to photic stimuli with progressive paralysis in 120 hpf larvae. Significantly decreased acetylcholinesterase (AChE) activity with lack of any CNS-specific apoptotic phenotypes as well as lack of changes in motor neuron density, axonal growth, muscle segment integrity or presence of myoseptal defects were detected upon exposure to plastic extracts during embryogenesis. Considering implications of the results for environmental risk assessment and the growing usage of 3D-printing technologies, we speculate that some 3D-printed plastic waste may represent a significant and yet very poorly uncharacterized environmental hazard that merits further investigation on a range of aquatic and terrestrial species.
        
Title: Synergistic effect of acetyl xylan esterase from Talaromyces leycettanus JCM12802 and xylanase from Neocallimastix patriciarum achieved by introducing carbohydrate-binding module-1 Zhang Y, Yang H, Yu X, Kong H, Chen J, Luo H, Bai Y, Yao B Ref: AMB Express, 9:13, 2019 : PubMed
Wheat bran is an effective raw material for preparation xylooligosaccharides; however, current research mainly focuses on alkali extraction and enzymatic hydrolysis methods. Since ester bonds are destroyed during the alkali extraction process, xylanase and arabinofuranosidase are mainly used to hydrolyze xylooligosaccharides. However, alkali extraction costs are very high, and the method also causes pollution. Therefore, this study focuses on elucidating a method to efficiently and directly degrade destarched wheat bran. First, an acidic acetyl xylan esterase (AXE) containing a carbohydrate-binding module-1 (CBM1) domain was cloned from Talaromyces leycettanus JCM12802 and successfully expressed in Pichia pastoris. Characterization showed that the full-length acetyl xylan esterase AXE + CBM1 was similar toe uncovered AXE with an optimum temperature and pH of 55 degrees C and 6.5, respectively. Testing the acetyl xylan esterase and xylanase derived from Neocallimastix patriciarum in a starch-free wheat bran cooperative experiment revealed that AXE + CBM1 and AXE produced 29% and 16% reducing sugars respectively, compared to when only NPXYN11 was used. In addition, introduced the CBM1 domain into NPXYN11, and the results indicated that the CBM1 domain showed little effect on NPXYN11 properties. Finally, the systematically synergistic effects between acetyl xylan esterase and xylanase with/without the CBM1 domain demonstrated that the combined ratio of AXE + CBM1 coming in first and NPXYN11 + CBM1 s increased reducing sugars by almost 35% with AXE and NPXYN11. Furthermore, each component's proportion remained the same with respect to xylooligosaccharides, with the largest proportion (86%) containing of 49% xylobiose and 37% xylotriose.
        
Title: An alkaline and surfactant-tolerant lipase from Trichoderma lentiforme ACCC30425 with high application potential in the detergent industry Wang Y, Ma R, Li S, Gong M, Yao B, Bai Y, Gu J Ref: AMB Express, 8:95, 2018 : PubMed
Alkaline lipases with adaptability to low temperatures and strong surfactant tolerance are favorable for application in the detergent industry. In the present study, a lipase-encoding gene, TllipA, was cloned from Trichoderma lentiforme ACCC30425 and expressed in Pichia pastoris GS115. The purified recombinant TlLipA was found to have optimal activities at 50 degreesC and pH 9.5 and retain stable over the pH range of 6.0-10.0 and 40 degreesC and below. When using esters of different lengths as substrates, TlLipA showed preference for the medium length p-nitrophenyl octanoate. In comparison to commercial lipases, TlLipA demonstrated higher tolerance to various surfactants (SDS, Tween 20, and Triton X100) and retained more activities after incubation with Triton X100 for up to 24 h. These favorable characteristics make TlLipA prospective as an additive in the detergent industry.
Background: inhibition of acetylcholinesterase (AChE) has been a effective treatment for Alzheimer's disease (AD). Octohydroaminoacridine, a new AChE inhibitor, is a potential treatment for AD. Method: we conducted a multicenter, randomised, double blind, placebo-controlled, parallel-group Phase II clinical trial to investigate the effects of octohydroaminoacridine in patients with mild-to-moderate AD. Patients were randomised to receive placebo thrice daily, octohydroaminoacridine 1 mg/thrice daily (TID) (low-dose group), 2 mg/TID (middle-dose group) or 4 mg/TID (high-dose group). Doses in the middle-dose and high-dose group were titrated over 2-4 weeks. Changes from baseline to Week 16 were assessed with the AD Assessment Scale-Cognitive Subscale (ADAS-cog), Clinician's Interview-Based Impression of Change Plus (CIBIC+), activities of daily living (ADL) and the neuropsychiatric inventory (NPI). ADAS-cog was the primary end point of the study. A two-way analysis of covariance and least squares mean t-test were used. Results: at Week 16, the changes from baseline in ADAS-cog were 1.4, -2.1, -2.2 and -4.2 for placebo, low-, middle- and high-dose groups, respectively. Patients in the high-dose group had better performance in CIBIC+ and ADL scores at the end of the study. There was no significant difference in the change in NPI score among the groups. The effects of octohydroaminoacridine were dose dependent, and were effective within 16 weeks of treatment. No evidence was found for more adverse events that occurred in different drug groups than placebo group. Conclusions: octohydroaminoacridine significantly improved cognitive function and behaviour in patients with mild-to-moderate AD and this effect was dose dependent.
        
Title: Ultrahigh pressure-assisted enzymatic extraction maximizes the yield of longan pulp polysaccharides and their acetylcholinesterase inhibitory activity in vitro Bai Y, Liu L, Zhang R, Huang F, Deng Y, Zhang M Ref: Int J Biol Macromol, 96:214, 2016 : PubMed
An extraction method employing ultrahigh pressure-assisted enzymatic treatment was developed and optimized by response surface methodology to increase the yield of longan pulp polysaccharides (LP-UE). A maximum polysaccharides yield of 8.55% was obtained under the optimal conditions of 407MPa ultrahigh pressure maintained for 6min with an enzyme to pretreated material ratio of 1:100, an enzymolysis time of 1.7h and a water to pretreated material ratio of 42ml/g. Subsequently, the physicochemical properties and acetylcholinesterase (AChE) inhibitory activity of LP-UE were compared to those of longan pulp polysaccharides (LP) extracted by hot water (LP-H), ultrahigh pressure (LP-U) or enzymatic treatment (LP-E). Results demonstrated that the extraction yield, hexuronic acid content and AChE inhibitory activity of LP-UE was the highest among the four LP samples. LP-UE was primarily made up of arabinose, glucose, and galactose and was linked mainly by beta-type glycosidic linkage. The FTIR spectrum of LP-UE was very similar to those of LP-H, LP-U, and LP-E. In summary, ultrahigh pressure-assisted enzymatic treatment is a more efficient technique for extracting LP with considerable improvement of both yield and memory enhancement function.
        
Title: Discovery of novel feruloyl esterase activity of BioH in Escherichia coli BL21(DE3) Kang L, Bai Y, Cai Y, Zheng X Ref: Biotechnol Lett, 38:1009, 2016 : PubMed
OBJECTIVES: To characterize a novel feruloyl esterase from Escherichia coli BL21 DE3. RESULTS: The gene encoding BioH was cloned and overexpressed in E. coli. The protein was purified and its catalytic activity was assessed. BioH exhibited feruloyl esterase activity toward a broad range of substrates, and the corresponding kinetic constants for the methyl ferulate, ethyl ferulate, and methyl p-coumarate substrates were: K m values of 0.48, 6.3, and 1.9 mM, respectively, and k cat /K m values of 9.3, 3.8, and 3.8 mM(-1) s(-1), respectively. CONCLUSIONS: Feruloyl esterase from E. coli was expressed for the first time. BioH was confirmed to be a feruloyl esterase.
We report the annotation and analysis of the draft genome sequence of Brassica rapa accession Chiifu-401-42, a Chinese cabbage. We modeled 41,174 protein coding genes in the B. rapa genome, which has undergone genome triplication. We used Arabidopsis thaliana as an outgroup for investigating the consequences of genome triplication, such as structural and functional evolution. The extent of gene loss (fractionation) among triplicated genome segments varies, with one of the three copies consistently retaining a disproportionately large fraction of the genes expected to have been present in its ancestor. Variation in the number of members of gene families present in the genome may contribute to the remarkable morphological plasticity of Brassica species. The B. rapa genome sequence provides an important resource for studying the evolution of polyploid genomes and underpins the genetic improvement of Brassica oil and vegetable crops.
The nonhuman primates most commonly used in medical research are from the genus Macaca. To better understand the genetic differences between these animal models, we present high-quality draft genome sequences from two macaque species, the cynomolgus/crab-eating macaque and the Chinese rhesus macaque. Comparison with the previously sequenced Indian rhesus macaque reveals that all three macaques maintain abundant genetic heterogeneity, including millions of single-nucleotide substitutions and many insertions, deletions and gross chromosomal rearrangements. By assessing genetic regions with reduced variability, we identify genes in each macaque species that may have experienced positive selection. Genetic divergence patterns suggest that the cynomolgus macaque genome has been shaped by introgression after hybridization with the Chinese rhesus macaque. Macaque genes display a high degree of sequence similarity with human disease gene orthologs and drug targets. However, we identify several putatively dysfunctional genetic differences between the three macaque species, which may explain functional differences between them previously observed in clinical studies.
Using next-generation sequencing technology alone, we have successfully generated and assembled a draft sequence of the giant panda genome. The assembled contigs (2.25 gigabases (Gb)) cover approximately 94% of the whole genome, and the remaining gaps (0.05 Gb) seem to contain carnivore-specific repeats and tandem repeats. Comparisons with the dog and human showed that the panda genome has a lower divergence rate. The assessment of panda genes potentially underlying some of its unique traits indicated that its bamboo diet might be more dependent on its gut microbiome than its own genetic composition. We also identified more than 2.7 million heterozygous single nucleotide polymorphisms in the diploid genome. Our data and analyses provide a foundation for promoting mammalian genetic research, and demonstrate the feasibility for using next-generation sequencing technologies for accurate, cost-effective and rapid de novo assembly of large eukaryotic genomes.
Cucumber is an economically important crop as well as a model system for sex determination studies and plant vascular biology. Here we report the draft genome sequence of Cucumis sativus var. sativus L., assembled using a novel combination of traditional Sanger and next-generation Illumina GA sequencing technologies to obtain 72.2-fold genome coverage. The absence of recent whole-genome duplication, along with the presence of few tandem duplications, explains the small number of genes in the cucumber. Our study establishes that five of the cucumber's seven chromosomes arose from fusions of ten ancestral chromosomes after divergence from Cucumis melo. The sequenced cucumber genome affords insight into traits such as its sex expression, disease resistance, biosynthesis of cucurbitacin and 'fresh green' odor. We also identify 686 gene clusters related to phloem function. The cucumber genome provides a valuable resource for developing elite cultivars and for studying the evolution and function of the plant vascular system.
        
Title: Lipase diversity in glacier soil based on analysis of metagenomic DNA fragments and cell culture Yuhong Z, Shi P, Liu W, Meng K, Bai Y, Wang G, Zhan Z, Yao B Ref: J Microbiol Biotechnol, 19:888, 2009 : PubMed
Lipase diversity in glacier soil was assessed by culture independent metagenomic DNA fragment screening and confirmed by cell culture experiments. A set of degenerate PCR primers specific for lipases of the hormone-sensitive lipase family was designed based on conserved motifs and used to directly PCR amplify metagenomic DNA from glacier soil. These products were used to construct a lipase fragment clone library. Among the 300 clones sequenced for the analysis, 201 clones encoding partial lipases shared 51-82%identity to known lipases in GenBank. Based on a phylogenetic analysis, five divergent clusters were established, one of which may represent a previously unidentified lipase subfamily. In the culture study, 11 lipase-producing bacteria were selectively isolated and characterized by 16S rDNA sequences. Using the above mentioned degenerate primers, seven lipase gene fragments were cloned, but not all of them could be accounted for by the clones in the library. Two full-length lipase genes obtained by TAIL-PCR were expressed in Pichia pastoris and characterized. Both were authentic lipases with optimum temperatures of
Triglyceride (TG) metabolism is crucial for whole body and local energy homeostasis and accumulating evidence suggests an independent association between plasma TG concentration and increased atherosclerosis risk. We previously generated a mouse insertional mutation lpd (lipid defect) whose phenotype included elevated plasma TG and hepatic steatosis. Using shotgun sequencing (approximately 500 kb) and bioinformatics, we have now identified a novel lipase gene lpdl (lpd lipase) within the lpd locus, and demonstrate the genetic disruption of exon 10 of lpdl in the lpd mutant locus. lpdl is highly expressed in the testis and weakly expressed in the liver of 2-week old mice. Human LPDL cDNA was subsequently cloned, and was found to encode a 460AA protein with 71% protein sequence identity to mouse lpdl and approximately 35% identity to other known lipases. We next sequenced the human LPDL gene exons in hypertriglyceridemic subjects and normal controls, and identified seven SNPs within the gene exons and six SNPs in the adjacent introns. Two hypertriglyceridemic subjects were heterozygous for a rare DNA variant, namely 164G>A (C55Y), which was absent from 600 normal chromosomes. Two other coding SNPs were associated with variation in plasma HDL cholesterol in independent normolipidemic populations. Using bioinformatics, we identified another novel lipase designated LPDLR (for 'LPDL related lipase'), which had 44% protein sequence identity with LPDL. Together with the phospholipase gene PSPLA1, LPDL and LPDLR form a new lipase gene subfamily, which is characterized by shortened lid motif. Study of this lipase subfamily may identify novel molecular mechanisms for plasma and/or tissue TG metabolism.
        
Title: Further confirmation of carboxypeptidase Y as a metal-free enzyme having a reactive serine residue Hayashi R, Bai Y, Hata T Ref: J Biochem, 77:1313, 1975 : PubMed
The metal content of carboxypeptidase Y was analyzed by the atomic absorption method. After exhaustive dialysis against an EDTA solution, the enzyme showed no loss of activity nor any significant content of metals (Zh,Mg,Ca,Cu,Mn,Ni,Fe, and Co). The activity was, however, rather sensitive to preincubation with various metals. The reactivity of a serine residue of the enzyme was also reevaluated. Diisopropyl fluorophosphate (DFP) and phenylmethanesulfonyl fluoride (PMSF) stoichiometrically and irreversively inhibited the enzyme. The rate of inactivation with DFP was much faster than that for typsin [EC 3.4.21.4] and chymotrypsin [EC 3.4.21.1.], while the rate with PMSF was one-fifteenth of that for chymotrypsin. The pH-dependence of the inactivation by DFP was similar to that of the enzymatic hydrolysis of acetylphenylalanine ethyl ester. The present results indicate that carboxypeptidase Y is free of metals and has a serine residue with a vital role in the catalytic process, though the functional role of this SH group remains to be clarified.