Title: Cymbopogon citratus (DC.) Stapf aqueous extract ameliorates loperamide-induced constipation in mice by promoting gastrointestinal motility and regulating the gut microbiota Gao X, Hu Y, Tao Y, Liu S, Chen H, Li J, Zhao Y, Sheng J, Tian Y, Fan Y Ref: Front Microbiol, 13:1017804, 2022 : PubMed
Slow transit constipation (STC) is the most common type of functional constipation. Drugs with good effects and few side effects are urgently needed form the treatment of STC. Cymbopogon citratus (DC.) Stapf (CC) is an important medicinal and edible spice plant. The wide range of biological activities suggested that CC may have laxative effects, but thus far, it has not been reported. In this study, the loperamide-induced STC mouse model was used to evaluate the laxative effect of the aqueous extract of CC (CCAE), and the laxative mechanism was systematically explored from the perspectives of the enteric nervous system (ENS), neurotransmitter secretion, gastrointestinal motility factors, intestinal inflammation, gut barrier and gut microbiota. The results showed that CCAE not only decreased the serum vasoactive intestinal polypeptide (VIP), induced nitric oxide synthases (iNOS), and acetylcholinesterase (AchE) in STC mice but also increased the expression of gastrointestinal motility factors in colonic interstitial cells of Cajal (ICCs) and smooth muscle cells (SMCs), thereby significantly shortening the defecation time and improving the gastrointestinal transit rate. The significantly affected gastrointestinal motility factors included stem cell factor receptor (c-Kit), stem cell factor (SCF), anoctamin 1 (Ano1), ryanodine receptor 3 (RyR3), smooth muscle myosin light chain kinase (smMLCK) and Connexin 43 (Cx43). Meanwhile, CCAE could repair loperamide-induced intestinal inflammation and intestinal barrier damage by reducing the expression of the pro-inflammatory factor IL-1beta and increasing the expression of the anti-inflammatory factor IL-10, chemical barrier (Muc-2) and mechanical barrier (Cldn4, Cldn12, Occludin, ZO-1, and ZO-2). Interestingly, CCAE could also partially restore loperamide-induced gut microbial dysbiosis in various aspects, such as microbial diversity, community structure and species composition. Importantly, we established a complex but clear network between gut microbiota and host parameters. Muribaculaceae, Lachnospiraceae and UCG-010 showed the most interesting associations with the laxative phenotypes; several other specific taxa showed significant associations with serum neurotransmitters, gastrointestinal motility factors, intestinal inflammation, and the gut barrier. These findings suggested that CCAE might promote intestinal motility by modulating the ENS-ICCs-SMCs network, intestinal inflammation, intestinal barrier and gut microbiota. CC may be an effective and safe therapeutic choice for STC.
In this paper, the acute toxicity of monobutyl phthalate (MBP), the main hydrolysis product of dibutyl phthalate, on adult zebrafish liver antioxidant system was studied. Compared the toxicity effect of MBP and DBP by histopathology and apoptosis experiments, we speculated that the toxic effects of DBP on animals may be caused by its metabolite MBP. The results indicated that the antioxidant Nrf2-Keap1 pathway was insufficient to resist MBP-induced hepatotoxicity and led to an imbalance of membrane ion homeostasis and liver damage. Decreased cell viability, significant tissue lesions and early hepatocyte apoptosis were observed in the zebrafish liver in MBP exposure at high concentration (10 mg/L). The activities of antioxidant enzymes and ATPases in zebrafish liver were inhibited with increased malondialdehyde (MDA) content and alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities. Integrated biomarker response (IBR) calculation results indicated that MBP mainly inhibited catalase (CAT) activity. Simultaneously, the expression of antioxidant-related genes (SOD, CAT, GPx, Nrf2, HO-1) was down-regulated, while apoptosis-related genes (p53, bax, cas3) were significantly up-regulated.
Title: Clinical characteristics and treatment of mixed-pesticide poisoning in a patient: reflections on a particular case Tao Y, Liu T, Han J, Jian X, Kan B Ref: J Internal Medicine Res, 48:300060520977392, 2020 : PubMed
Patients who commit suicide often deliberately hide their medical history. Given that taking pesticides is one of the most common methods of suicide, other forms of poisoning may be neglected in clinical practice. We report here a case of mixed-pesticide poisoning. The patient was poisoned by oral administration of a coumarin rodenticide in combination with an intramuscular injection of organophosphorus (OP) pesticide. The patient was treated with vitamin K1, cholinesterase reactivators, atropine, ventilator-assisted ventilation, and bedside debridement. Her condition gradually stabilized and she eventually recovered and was discharged. Assessment of the causes of delayed diagnosis and treatment suggests that we need to improve early detection and treatment of acute poisoning. It is especially important to ask about the patient's medical history, conduct a careful physical examination, and track the clinical symptoms and differential diagnosis of common poisoning. In addition to the three common routes of poisoning-oral, inhalation, and cutaneous mucosal contact-intramuscular injection of OP can also lead to severe poisoning, which manifests as respiratory failure.
Title: Enhancing the atypical esterase promiscuity of the gamma-lactamase Sspg from Sulfolobus solfataricus by substrate screening Wang J, Zhao H, Zhao G, Chen D, Tao Y, Wu S Ref: Applied Microbiology & Biotechnology, 103:4077, 2019 : PubMed
Promiscuous enzymes can be modified by protein engineering, which enables the catalysis of non-native substrates. gamma-lactamase Sspg from Sulfolobus solfataricus is an enzyme with high activity, high stability, and pronounced tolerance of high concentrations of the gamma-lactam substrate. These characteristics suggest Sspg as a robust enzymatic catalyst for the preparation of optically pure gamma-lactam. This study investigated the modification of this enzyme to expand its application toward resolving chiral esters. gamma-Lactamase-esterase conversion was performed by employing a three-step method: initial sequence alignment, followed by substrate screening, and protein engineering based on the obtained substrate-enzyme docking results. This process of fine-tuning of chemical groups on substrates has been termed "substrate screening." Steric hindrance and chemical reactivity of the substrate are major concerns during this step, since both are determining factors for the enzyme-substrate interaction. By employing this three-step method, gamma-lactamase Sspg was successfully converted into an esterase with high enantioselectivity towards phenylglycidate substrates (E value > 300). However, since both wild-type Sspg and Sspg mutants did not hydrolyze para-nitrophenyl substrates (pNPs), this esterase activity was termed "atypical esterase activity." The gamma-lactamase activity and stability of the Sspg mutants were not severely compromised. The proposed method can be applied to find novel multi-functional enzyme catalysts within existing enzyme pools.
Title: Synergistic effects of amine and protein modified epoxy-support on immobilized lipase activity Cui C, Tao Y, Ge C, Zhen Y, Chen B, Tan T Ref: Colloids Surf B Biointerfaces, 133:51, 2015 : PubMed
We have developed an improved and effective method to immobilize Yarrowia lipolytica lipase Lip2 (YLIP2) on an epoxy poly-(glycidylmethacrylate-triallyisocyanurate-ethyleneglycoldimethacrylate) (PGMA-TAIC-EGDMA) support structure with or without amine or/and protein modifications. Our results show that there is an increase in the activity of the immobilized lipase on n-butylamine (BA) modified support (420U/g support) and the biocompatible gelatin modified support (600U/g support) when compared to the support without modification (240U/g support). To further study the influences of BA and gelatin modification on the activity of the immobilized lipase, gelatin and BA were concurrently used to decorate the support structure. Lipase immobilized on 2% BA/gelatin (1:1) modified support obtained the highest activity (1180U/g support), which was five-fold higher than that on a native support structure. These results suggest that the activity of a support-immobilized lipase depends on the support surface properties and a moderate support surface micro-environment was crucial for elevated activity. Collectively, these data show that a combined gelatin and BA modification regulates the support surface more suitable for immobilizing YLIP2.
Using a whole-genome-sequencing approach to explore germplasm resources can serve as an important strategy for crop improvement, especially in investigating wild accessions that may contain useful genetic resources that have been lost during the domestication process. Here we sequence and assemble a draft genome of wild soybean and construct a recombinant inbred population for genotyping-by-sequencing and phenotypic analyses to identify multiple QTLs relevant to traits of interest in agriculture. We use a combination of de novo sequencing data from this work and our previous germplasm re-sequencing data to identify a novel ion transporter gene, GmCHX1, and relate its sequence alterations to salt tolerance. Rapid gain-of-function tests show the protective effects of GmCHX1 towards salt stress. This combination of whole-genome de novo sequencing, high-density-marker QTL mapping by re-sequencing and functional analyses can serve as an effective strategy to unveil novel genomic information in wild soybean to facilitate crop improvement.
Colobines are a unique group of Old World monkeys that principally eat leaves and seeds rather than fruits and insects. We report the sequencing at 146x coverage, de novo assembly and analyses of the genome of a male golden snub-nosed monkey (Rhinopithecus roxellana) and resequencing at 30x coverage of three related species (Rhinopithecus bieti, Rhinopithecus brelichi and Rhinopithecus strykeri). Comparative analyses showed that Asian colobines have an enhanced ability to derive energy from fatty acids and to degrade xenobiotics. We found evidence for functional evolution in the colobine RNASE1 gene, encoding a key secretory RNase that digests the high concentrations of bacterial RNA derived from symbiotic microflora. Demographic reconstructions indicated that the profile of ancient effective population sizes for R. roxellana more closely resembles that of giant panda rather than its congeners. These findings offer new insights into the dietary adaptations and evolutionary history of colobine primates.
Title: Electrochemical detection of dual exposure biomarkers of organophosphorus agents based on reactivation of inhibited cholinesterase Ge X, Tao Y, Zhang A, Lin Y, Du D Ref: Analytical Chemistry, 85:9686, 2013 : PubMed
Considering inter- or intra-individual variation in the normal levels of acetylcholinesterase (AChE), real-time measurement of AChE via the reactivation from a postexposure sample was used, and thus a baseline-free and reliable approach was proposed for detecting/screening low-dose organophosphorus pesticides (OPs) poisons. The principle of this technology is on the basis of parallel measurements of AChE activity before and after reactivation from a postexposure to simultaneously provide the content of dual biomarkers of both enzyme inhibition and enzyme adducts. It is more accurate and reliable compared with only one biomarker (inhibition or adduct). Reactivation from a postexposure sample is a better individual enzyme baseline compared to pre-exposure from the population average level in currently available approaches. AChE activity was measured with an electrochemical method. Greatly enhanced sensitivity was achieved by using Fe3O4/Au nanocomposites to enrich thiocholine, the hydrolysis product of active AChE, followed by electrochemical oxidative desorption of the adsorbed thiocholine. The validation of this method for measurement of OP exposures was further explored with in vitro paraoxon inhibited human red blood cells (RBCs) samples and demonstrated its practicability.
Bread wheat (Triticum aestivum, AABBDD) is one of the most widely cultivated and consumed food crops in the world. However, the complex polyploid nature of its genome makes genetic and functional analyses extremely challenging. The A genome, as a basic genome of bread wheat and other polyploid wheats, for example, T. turgidum (AABB), T. timopheevii (AAGG) and T. zhukovskyi (AAGGA(m)A(m)), is central to wheat evolution, domestication and genetic improvement. The progenitor species of the A genome is the diploid wild einkorn wheat T. urartu, which resembles cultivated wheat more extensively than do Aegilops speltoides (the ancestor of the B genome) and Ae. tauschii (the donor of the D genome), especially in the morphology and development of spike and seed. Here we present the generation, assembly and analysis of a whole-genome shotgun draft sequence of the T. urartu genome. We identified protein-coding gene models, performed genome structure analyses and assessed its utility for analysing agronomically important genes and for developing molecular markers. Our T. urartu genome assembly provides a diploid reference for analysis of polyploid wheat genomes and is a valuable resource for the genetic improvement of wheat.
Title: Improved production of heterologous lipase in Trichoderma reesei by RNAi mediated gene silencing of an endogenic highly expressed gene Qin LN, Cai FR, Dong XR, Huang ZB, Tao Y, Huang JZ, Dong ZY Ref: Bioresour Technol, 109:116, 2012 : PubMed
A lipase gene (Lip) of the Aspergillus niger was de novo synthesized and expressed in the Trichoderma reesei under the promoter of the cellobiohydrolase I gene (cbh1). RNAi-mediated gene silencing was successfully used to further improve the recombinant lipase production via down-regulation of CBHI which comprised more than 60% of the total extracellular proteins in T. reesei. The gene and protein expression of CBHI and recombinant lipase were analyzed by real-time PCR, SDS-PAGE and activity assay. The results demonstrated that RNAi-mediated gene silencing could effectively suppress cbh1 gene expression and the reduction of CBHI could result in obvious improvement of heterologous lipase production. The reconstructed strains with decreased CBHI production exhibited 1.8- to 3.2-fold increase in lipase activity than that of parental strain. The study herein provided a feasible and advantageous method of increasing heterologous target gene expression in T. reesei through preventing the high expression of a specific endogenenous gene by RNA interference.
Title: Oxidative desorption of thiocholine assembled on core-shell Fe3O4/AuNPs magnetic nanocomposites for highly sensitive determination of acetylcholinesterase activity: an exposure biomarker of organophosphates Du D, Tao Y, Zhang W, Liu D, Li H Ref: Biosensors & Bioelectronics, 26:4231, 2011 : PubMed
Acetylcholinesterase (AChE) activity is a well established biomarker for biomonitoring of exposures to organophosphates (OPs) pesticides and chemical nerve agents. In this work, we described a novel electrochemical oxidative desorption-process of thiocholine, the product of enzymatic reaction, for rapid and highly sensitive determination of AChE activity in human serum. This principle is based on self-assembling of produced thiocholine onto core-shell Fe(3)O(4)/Au nanoparticles (Fe(3)O(4)/AuNPs) magnetic nanocomposites and its oxidation at electrode surface. Fe(3)O(4) magnetic core is not only used for magnetic separation from sample solutions, but also carrying more AuNPs due to its large surface-to-volume ratio. The core-shell Fe(3)O(4)/AuNPs nanocomposites were characterized by UV-Vis spectroscopy, field-emission scanning electron microscopy (FE-SEM) and electrochemical measurements. A linear relationship was obtained between the AChE activity and its concentration from 0.05 to 5.0 mU mL(-1) with a detection limit of 0.02 mU mL(-1). The method showed good results for characterization of AChE spiked human serum and detection of OP exposures from 0.05 to 20 nM, with detection limit of 0.02 nM. This new oxidative desorption assay thus provides a sensitive and quantitative tool for biomonitoring of the exposure to OP pesticides and nerve agents.
Endothelial lipase, which is a newly identified member of the lipase family, plays an important role in high-density lipoprotein metabolism, which catalyzes the hydrolysis of high-density lipoprotein phospholipids and facilitates the clearance of high-density lipoprotein from the circulation. In addition, inflammatory cytokines, including tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 beta (IL-1beta), upregulate endothelial lipase expression, and endothelial lipase also affects the expression of cytokines, which in turn play an important role in atherogenesis. Endothelial lipase expression has been associated with macrophages within human atherosclerotic lesions. However, an important challenge is to determine how endothelial lipase alters the progression of atherosclerosis. Although few data are available from human studies, it seems that plasma endothelial lipase levels in individuals with atherosclerosis might be higher than that measured in healthy individuals. Therefore, we believe that endothelial lipase might be a promising marker for atherosclerosis in clinical settings in the future.
Title: Immobilization of acetylcholinesterase based on the controllable adsorption of carbon nanotubes onto an alkanethiol monolayer for carbaryl sensing Du D, Wang M, Cai J, Tao Y, Tu H, Zhang A Ref: Analyst, 133:1790, 2008 : PubMed
A simple method to immobilize acetylcholinesterase (AChE) on the controllable adsorption of multiwalled carbon nanotubes (MWCNTs) onto an alkanethiol self-assembled monolayer (C(6)H(13)SH SAM) modified Au electrode was proposed. The surface coverage of the MWCNTs was readily controlled by adjusting the immersion time for the adsorption of the MWCNTs. Atomic force microscopy (AFM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to monitor these controllable fabrication processes. The MWCNTs adsorbed onto the SAM surface substantially restores the heterogeneous electron transfer between the bare Au electrode and the redox system in the solution phase that is almost totally blocked by the SAM of C(6)H(13)SH, and as a result, the prepared MWCNT-SAM-modified electrode possesses good electrode reactivity without a remarkable barrier to heterogeneous electron transfer. Due to the inherent conductive properties of MWCNTs, the immobilized AChE exhibited high affinity to its substrate and produced a detectable and fast response. Thus, a sensitive, efficient and stable amperometric sensor for quantitative determination of carbaryl was developed. The inhibition of carbaryl was proportional to its concentration ranging from 0.001 to 1 microg mL(-1) and 2 to 15 microg mL(-1), with a detection limit of 0.6 ng mL(-1). The determination of carbaryl in garlic samples showed acceptable accuracy, which provided a new promising tool for analysis of enzyme inhibitors.
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.
