Avian pathogenic Escherichia coli(APEC)belonging to extraintestinal pathogenic E.coli(ExPEC)can cause severe infections in extraintestinal tissues in birds and humans,such as the lungs and blood.MprA(microcin producti...Avian pathogenic Escherichia coli(APEC)belonging to extraintestinal pathogenic E.coli(ExPEC)can cause severe infections in extraintestinal tissues in birds and humans,such as the lungs and blood.MprA(microcin production regulation,locus A,herein renamed AbsR,a blood survival regulator),a member of the MarR(multiple antibiotic resistance regulator)transcriptional regulator family,governs the expression of capsule biosynthetic genes in human ExPEC and represents a promising druggable target for antimicrobials.However,a deep understanding of the AbsR regulatory mechanism as well as its regulon is lacking.In this study,we present a systems-level analysis of the APEC AbsR regulon using ChIP-Seq(chromatin immunoprecipitation sequencing)and RNA-Seq(RNA sequencing)methods.We found that AbsR directly regulates 99 genes and indirectly regulates 667 genes.Furthermore,we showed that:1)AbsR contributes to antiphagocytotic effects by macrophages and virulence in a mouse model for systemic infection by directly activating the capsular gene cluster;2)AbsR positively impacts biofilm formation via direct regulation of the T2SS(type II secretion system)but plays a marginal role in virulence;and 3)AbsR directly upregulates the acid tolerance signaling system EvgAS to withstand acid stress but is dispensable in ExPEC virulence.Finally,our data indicate that the role of AbsR in virulence gene regulation is relatively conserved in ExPEC strains.Altogether,this study provides a comprehensive analysis of the AbsR regulon and regulatory mechanism,and our data suggest that AbsR likely influences virulence primarily through the control of capsule production.Interestingly,we found that AbsR severely represses the expression of the type I-F CRISPR(clustered regularly interspaced short palindromic repeats)-Cas(CRISPR associated)systems,which could have implications in CRISPR biology and application.展开更多
Based on the overview of the role played by farmers' co-operatives in developing rural economy and existing problems,the thesis has introduced the factors which influence the development of farmers' co-operati...Based on the overview of the role played by farmers' co-operatives in developing rural economy and existing problems,the thesis has introduced the factors which influence the development of farmers' co-operatives including five aspects,namely conditions of scale economy,popularization and application of agricultural production technology,comparative advantage,market expectancy and government support.By analyzing typical cases of three co-operatives in Guangxi(Heng County Dadi Growing Co-operatives,talents-leading share-holding co-operatives;Long'an County Guixiniu Co-operatives,co-operatives led by leading-enterprise;Nanning City Tanluo Town Jinguang Fruits and Potatoes Co-operatives,co-operatives led by leading-enterprise),the way to develop farmers' co-operatives by dint of the external capital has been discussed.The results demonstrate that conditions of scale economy,popularization and application of agricultural production technology,comparative advantage,excellent market expectancy and government support,are conducive to absorbing external capital.Under China's existing economic conditions,the government should normalize the use and allocation procedure of program fund.展开更多
The aim of the present study was to characterize a collection of Escherichia coli strains isolated from asymptomatic griffon vulture (Gyps fulvus) during a reintroduction program in the southeast of Spain, in order to...The aim of the present study was to characterize a collection of Escherichia coli strains isolated from asymptomatic griffon vulture (Gyps fulvus) during a reintroduction program in the southeast of Spain, in order to establish if griffon vulture could play a role in the spread of resistant or potentially pathogenic E. coli strains. For this purpose, 14 E. coli strains obtained from 10 griffon vulture were studied to establish their serotypes, phylogroups, virulencegene profiles and antimicrobial resistances. High heterogeneity was observed within the 14 strains isolated which belonged to three phylogroups (A, B1 and D), 8 serogroups (O2, O21, O29, O60, 073, O78, O103 and O141) and 13 different serotypes. Out of 34 genes screened, we have detected eight virulence genes that are typical of extraintestinal pathogenic E. coli (ExPEC) (fimH, fimAvMT78, iroN, iucD, cvaC, iss, traT and tsh);however, none of the studied strains showed the ExPEC status. The 14 strains were also analyzed for the production of extended-spectrum beta-lactamases (ESBLs) and for antimicrobial resistances. None of the 14 strains were ESBL-producing E. coli, but high resistance-prevalences to ampicillin and cotrimoxazole were detected. To our knowledge, this is the first characterization of E. coli strains isolated from griffon vulture and although they did not show high virulencegene scores, they showed cotrimoxazole resistance.展开更多
Monetary Research Center,Bank of Communication Weaker Chinese export competitiveness As the economy for the first quarter keeps going down,the government has issued stimulus policies since March.These policies belong ...Monetary Research Center,Bank of Communication Weaker Chinese export competitiveness As the economy for the first quarter keeps going down,the government has issued stimulus policies since March.These policies belong to four categories including investment,foreign trade,finance展开更多
基金supported by the National Natural Science Foundation of China Young Scholars Project(31902242)the Agricultural Science and Technology Innovation Program(ASTIP)of Chinese Academy of Agricultural Sciences(2017–2020)。
文摘Avian pathogenic Escherichia coli(APEC)belonging to extraintestinal pathogenic E.coli(ExPEC)can cause severe infections in extraintestinal tissues in birds and humans,such as the lungs and blood.MprA(microcin production regulation,locus A,herein renamed AbsR,a blood survival regulator),a member of the MarR(multiple antibiotic resistance regulator)transcriptional regulator family,governs the expression of capsule biosynthetic genes in human ExPEC and represents a promising druggable target for antimicrobials.However,a deep understanding of the AbsR regulatory mechanism as well as its regulon is lacking.In this study,we present a systems-level analysis of the APEC AbsR regulon using ChIP-Seq(chromatin immunoprecipitation sequencing)and RNA-Seq(RNA sequencing)methods.We found that AbsR directly regulates 99 genes and indirectly regulates 667 genes.Furthermore,we showed that:1)AbsR contributes to antiphagocytotic effects by macrophages and virulence in a mouse model for systemic infection by directly activating the capsular gene cluster;2)AbsR positively impacts biofilm formation via direct regulation of the T2SS(type II secretion system)but plays a marginal role in virulence;and 3)AbsR directly upregulates the acid tolerance signaling system EvgAS to withstand acid stress but is dispensable in ExPEC virulence.Finally,our data indicate that the role of AbsR in virulence gene regulation is relatively conserved in ExPEC strains.Altogether,this study provides a comprehensive analysis of the AbsR regulon and regulatory mechanism,and our data suggest that AbsR likely influences virulence primarily through the control of capsule production.Interestingly,we found that AbsR severely represses the expression of the type I-F CRISPR(clustered regularly interspaced short palindromic repeats)-Cas(CRISPR associated)systems,which could have implications in CRISPR biology and application.
文摘Based on the overview of the role played by farmers' co-operatives in developing rural economy and existing problems,the thesis has introduced the factors which influence the development of farmers' co-operatives including five aspects,namely conditions of scale economy,popularization and application of agricultural production technology,comparative advantage,market expectancy and government support.By analyzing typical cases of three co-operatives in Guangxi(Heng County Dadi Growing Co-operatives,talents-leading share-holding co-operatives;Long'an County Guixiniu Co-operatives,co-operatives led by leading-enterprise;Nanning City Tanluo Town Jinguang Fruits and Potatoes Co-operatives,co-operatives led by leading-enterprise),the way to develop farmers' co-operatives by dint of the external capital has been discussed.The results demonstrate that conditions of scale economy,popularization and application of agricultural production technology,comparative advantage,excellent market expectancy and government support,are conducive to absorbing external capital.Under China's existing economic conditions,the government should normalize the use and allocation procedure of program fund.
文摘The aim of the present study was to characterize a collection of Escherichia coli strains isolated from asymptomatic griffon vulture (Gyps fulvus) during a reintroduction program in the southeast of Spain, in order to establish if griffon vulture could play a role in the spread of resistant or potentially pathogenic E. coli strains. For this purpose, 14 E. coli strains obtained from 10 griffon vulture were studied to establish their serotypes, phylogroups, virulencegene profiles and antimicrobial resistances. High heterogeneity was observed within the 14 strains isolated which belonged to three phylogroups (A, B1 and D), 8 serogroups (O2, O21, O29, O60, 073, O78, O103 and O141) and 13 different serotypes. Out of 34 genes screened, we have detected eight virulence genes that are typical of extraintestinal pathogenic E. coli (ExPEC) (fimH, fimAvMT78, iroN, iucD, cvaC, iss, traT and tsh);however, none of the studied strains showed the ExPEC status. The 14 strains were also analyzed for the production of extended-spectrum beta-lactamases (ESBLs) and for antimicrobial resistances. None of the 14 strains were ESBL-producing E. coli, but high resistance-prevalences to ampicillin and cotrimoxazole were detected. To our knowledge, this is the first characterization of E. coli strains isolated from griffon vulture and although they did not show high virulencegene scores, they showed cotrimoxazole resistance.
文摘Monetary Research Center,Bank of Communication Weaker Chinese export competitiveness As the economy for the first quarter keeps going down,the government has issued stimulus policies since March.These policies belong to four categories including investment,foreign trade,finance
