III型分泌系统(type III secretion system,T3SS)是副溶血弧菌主要的毒力因子之一,能传递与致病有关的毒性因子来发挥病原菌的毒性,而温度是影响细菌基因表达等生命活动的关键生态因子。本文以ATCC17802和JA21作为实验菌株,分别提取其R...III型分泌系统(type III secretion system,T3SS)是副溶血弧菌主要的毒力因子之一,能传递与致病有关的毒性因子来发挥病原菌的毒性,而温度是影响细菌基因表达等生命活动的关键生态因子。本文以ATCC17802和JA21作为实验菌株,分别提取其RNA,在不同温度和温度应激条件下,以pvuA为内参基因,以副溶血弧菌T3SS1的vcrD1、vopS、vopD1和T3SS2的vscC2β、vcrD2β、vopP2β作为目的基因,运用荧光定量PCR(RT-PCR)技术检测T3SS相关基因的表达下,用ΔΔCt法计算基因表达差异。结果表明:副溶血弧菌(Vibrio parahaemolyticus)ATCC17802菌株的T3SS1基因在16℃表达量最高,T3SS2基因在25℃表达量最高。副溶血弧菌JA21菌株的T3SS1基因和T3SS2基因均在25℃表达量最高。2株副溶血弧菌从不同的培养温度转入到应激温度37℃后,T3SS1和T3SS2基因的表达量均被显著诱导,并表现出时间依赖性,呈现先升高后降低的趋势。这为进一步探究环境因素与副溶血弧菌致病力的关系提供了科学依据。展开更多
Xanthomonas oryzea pv.oryzae(Xoo)is the causal agent of bacterial blight of rice,which is a significant threat to many of rice-growing regions.The type Ⅲ secretion system(T3SS)is an essential virulence factor in Xoo....Xanthomonas oryzea pv.oryzae(Xoo)is the causal agent of bacterial blight of rice,which is a significant threat to many of rice-growing regions.The type Ⅲ secretion system(T3SS)is an essential virulence factor in Xoo.Expression of the T3SS is often induced in the host environment or in hrp-inducing medium but is repressed in nutrient-rich medium.The elucidation of molecular mechanism underlying induction of T3SS genes expression is a very important step to lift the veil on global virulence regulation network in Xoo.Thus,an efficient and reliable genetic tool system is required for detection of the T3SS proteins.In this study,we constructed a protein expression vector pH3-flag based on the backbone of pHM1,a most widely used vector in Xoo strains,especially a model strain PXO99A.This vector contains a synthesized MCS-FLAG cassette that consists of a multiple cloning site(MCS),containing a modified pUC18 polylinker,and Flag as a C-terminal tag.The cassette is flanked by transcriptional terminators to eliminate interference of external transcription enabling detection of accurate protein expression.We evaluated the potential of this expression vector as T3SS proteins detection system and demonstrated it is applicable in the study of T3SS genes expression regulation in Xoo.This improved expression system could be very effectively used as a molecular tool in understanding some virulence genes expression and regulation in Xoo and other Xanthomonas spp.展开更多
Plant bacterial diseases have infiicted substantial economic losses in global crop,fruit,and vegetable production.The conventional methods for managing these diseases typically rely on the application of antibiotics.H...Plant bacterial diseases have infiicted substantial economic losses in global crop,fruit,and vegetable production.The conventional methods for managing these diseases typically rely on the application of antibiotics.However,these antibiotics often target the growth factors of the pathogenic bacteria,leading to the accumulation and emergence of drug-resistant strains,which exacerbates antibiotic resistance.Innovative methods are urgently needed to treat and prevent the toxicity caused by these pathogenic bacteria.Targeting virulence mechanisms in pathogens is a globally recognized and effective strategy for mitigating bacterial resistance.TypeⅢsecretion system(T3SS)serves as a crucial virulence determinant in Gram-negative pathogens,and its non-essentials for pathogen growth renders it an ideal target.Targeting the T3SS holds significant potential to alleviate selective pressure for resistance mutations in pathogens.Therefore,targeting T3SS in pathogenic bacteria,while preserving their growth,has emerged as a novel avenue for the development of antimicrobial drugs.In recent years,a multitude of small molecular inhibitors targeting T3SS have been identified.This article offers a comprehensive review of T3SS inhibitors in plant pathogens,while also presenting the latest research advancements in this research direction.展开更多
Pseudomonas aeruginosa is a significant pathogen mainly causing healthcare-associated infections(HAIs).Newly emerging high-risk clones of P.aeruginosa with elevated virulence profiles furtherly cause severe community-...Pseudomonas aeruginosa is a significant pathogen mainly causing healthcare-associated infections(HAIs).Newly emerging high-risk clones of P.aeruginosa with elevated virulence profiles furtherly cause severe community-acquired infections(CAIs).Usually,it is not common for P.aeruginosa to co-carry exoU and exoS genes,encoding two type III secretion system(T3SS)effectors.The pathogenicity mechanism of exoS+/exoU+strains of P.aeruginosa remains unclear.Here,we provide detailed evidence for a subset of hypervirulent P.aeruginosa strains,which abundantly co-express and secrete the T3SS effectors ExoS and ExoU.The exoS+/exoU+P.aeruginosa strains were available to cause both HAIs and CAIs.The CAI-associated strains could elicit severe inflammation and hemorrhage,leading to higher death rates in a murine acute pneumonia model,and had great virulence potential in establishing chronic infections,demonstrating hypervirulence when compared to PAO1(exoS+/exoU-)and PA14(exoS-/exoU+).Both ExoS and ExoU were co-expressed and co-secreted in abundance in exoS+/exoU+strains.Their abundant protein secretion could boost exoS+/exoU+strains’potentials for cytotoxicity in vitro and pathogenicity in vivo.Genomic evidence indicates that exoU acquisition is likely mediated by horizontal gene transfer(HGT)of the pathogenicity island PAPI-2,while deletion of exoU was sufficient to mitigate virulence in the exoS+/exoU+strains.Furthermore,bioinformatics analysis showed that such exoS+/exoU+P.aeruginosa strains turned out to be widely distributed across the globe.Overall,the research provide detailed evidence for the high virulence and epidemicity of exoS+/exoU+strains of P.aeruginosa,highlighting an urgent need for surveillance against these high-risk hypervirulent strains.展开更多
Vibrio parahaemolyticus,a gram-negative halophilic bacterium that naturally inhabits coastal waters,causes gastroenteritis,skin infections,and septicemia in human beings[1].This bacterium produces multiple virulence f...Vibrio parahaemolyticus,a gram-negative halophilic bacterium that naturally inhabits coastal waters,causes gastroenteritis,skin infections,and septicemia in human beings[1].This bacterium produces multiple virulence factors,including thermostable direct hemolysin(TDH),TDH-related hemolysin(TRH),type Ⅲ secretion system 1(T3SS1),T3SS2,type Ⅵ secretion system 1(T6SS1),and T6SS2[1].Furthermore,Ⅴ.parahaemolyticus forms biofilms on the surface,which help it in adapting to unfavorable conditions[2].Mature biofilm formation requires special structures,including lateral and polar flagella,exopolysaccharide(EPS),and type Ⅳ pili[2].展开更多
文摘III型分泌系统(type III secretion system,T3SS)是副溶血弧菌主要的毒力因子之一,能传递与致病有关的毒性因子来发挥病原菌的毒性,而温度是影响细菌基因表达等生命活动的关键生态因子。本文以ATCC17802和JA21作为实验菌株,分别提取其RNA,在不同温度和温度应激条件下,以pvuA为内参基因,以副溶血弧菌T3SS1的vcrD1、vopS、vopD1和T3SS2的vscC2β、vcrD2β、vopP2β作为目的基因,运用荧光定量PCR(RT-PCR)技术检测T3SS相关基因的表达下,用ΔΔCt法计算基因表达差异。结果表明:副溶血弧菌(Vibrio parahaemolyticus)ATCC17802菌株的T3SS1基因在16℃表达量最高,T3SS2基因在25℃表达量最高。副溶血弧菌JA21菌株的T3SS1基因和T3SS2基因均在25℃表达量最高。2株副溶血弧菌从不同的培养温度转入到应激温度37℃后,T3SS1和T3SS2基因的表达量均被显著诱导,并表现出时间依赖性,呈现先升高后降低的趋势。这为进一步探究环境因素与副溶血弧菌致病力的关系提供了科学依据。
基金supported by the National Key R&D Program of China (2017YFD0200400)the National Natural Science Foundation of China (31772122 and 31470235)
文摘Xanthomonas oryzea pv.oryzae(Xoo)is the causal agent of bacterial blight of rice,which is a significant threat to many of rice-growing regions.The type Ⅲ secretion system(T3SS)is an essential virulence factor in Xoo.Expression of the T3SS is often induced in the host environment or in hrp-inducing medium but is repressed in nutrient-rich medium.The elucidation of molecular mechanism underlying induction of T3SS genes expression is a very important step to lift the veil on global virulence regulation network in Xoo.Thus,an efficient and reliable genetic tool system is required for detection of the T3SS proteins.In this study,we constructed a protein expression vector pH3-flag based on the backbone of pHM1,a most widely used vector in Xoo strains,especially a model strain PXO99A.This vector contains a synthesized MCS-FLAG cassette that consists of a multiple cloning site(MCS),containing a modified pUC18 polylinker,and Flag as a C-terminal tag.The cassette is flanked by transcriptional terminators to eliminate interference of external transcription enabling detection of accurate protein expression.We evaluated the potential of this expression vector as T3SS proteins detection system and demonstrated it is applicable in the study of T3SS genes expression regulation in Xoo.This improved expression system could be very effectively used as a molecular tool in understanding some virulence genes expression and regulation in Xoo and other Xanthomonas spp.
基金the financial support from the National Key Research and Development Program of China(No.2023YFD1701100)the National Natural Science Foundation of China(No.32072450)+2 种基金the National Science Fund for Distinguished Young Scholars of Guangdong Province(No.2021B1515020107)the Opening Foundation of Hubei Key Laboratory of Novel Reactor and Green Chemical Technology(No.NRG202306)the Opening Foundation of Guangdong Province Key Laboratory of Microbial Signals and Disease Control(No.MSDC2023-19)。
文摘Plant bacterial diseases have infiicted substantial economic losses in global crop,fruit,and vegetable production.The conventional methods for managing these diseases typically rely on the application of antibiotics.However,these antibiotics often target the growth factors of the pathogenic bacteria,leading to the accumulation and emergence of drug-resistant strains,which exacerbates antibiotic resistance.Innovative methods are urgently needed to treat and prevent the toxicity caused by these pathogenic bacteria.Targeting virulence mechanisms in pathogens is a globally recognized and effective strategy for mitigating bacterial resistance.TypeⅢsecretion system(T3SS)serves as a crucial virulence determinant in Gram-negative pathogens,and its non-essentials for pathogen growth renders it an ideal target.Targeting the T3SS holds significant potential to alleviate selective pressure for resistance mutations in pathogens.Therefore,targeting T3SS in pathogenic bacteria,while preserving their growth,has emerged as a novel avenue for the development of antimicrobial drugs.In recent years,a multitude of small molecular inhibitors targeting T3SS have been identified.This article offers a comprehensive review of T3SS inhibitors in plant pathogens,while also presenting the latest research advancements in this research direction.
基金supported by grants from the National Key R&D Program of China(2021YFC2302005)the Joint Funds of the International Development Research Center of Canada(109282-001)the National Key R&D Program of China(2021YFC2301004 and 2017YFE0125600).
文摘Pseudomonas aeruginosa is a significant pathogen mainly causing healthcare-associated infections(HAIs).Newly emerging high-risk clones of P.aeruginosa with elevated virulence profiles furtherly cause severe community-acquired infections(CAIs).Usually,it is not common for P.aeruginosa to co-carry exoU and exoS genes,encoding two type III secretion system(T3SS)effectors.The pathogenicity mechanism of exoS+/exoU+strains of P.aeruginosa remains unclear.Here,we provide detailed evidence for a subset of hypervirulent P.aeruginosa strains,which abundantly co-express and secrete the T3SS effectors ExoS and ExoU.The exoS+/exoU+P.aeruginosa strains were available to cause both HAIs and CAIs.The CAI-associated strains could elicit severe inflammation and hemorrhage,leading to higher death rates in a murine acute pneumonia model,and had great virulence potential in establishing chronic infections,demonstrating hypervirulence when compared to PAO1(exoS+/exoU-)and PA14(exoS-/exoU+).Both ExoS and ExoU were co-expressed and co-secreted in abundance in exoS+/exoU+strains.Their abundant protein secretion could boost exoS+/exoU+strains’potentials for cytotoxicity in vitro and pathogenicity in vivo.Genomic evidence indicates that exoU acquisition is likely mediated by horizontal gene transfer(HGT)of the pathogenicity island PAPI-2,while deletion of exoU was sufficient to mitigate virulence in the exoS+/exoU+strains.Furthermore,bioinformatics analysis showed that such exoS+/exoU+P.aeruginosa strains turned out to be widely distributed across the globe.Overall,the research provide detailed evidence for the high virulence and epidemicity of exoS+/exoU+strains of P.aeruginosa,highlighting an urgent need for surveillance against these high-risk hypervirulent strains.
基金supported by the Natural Science Research Project of the Nantong Science and Technology Bureau(Grant No.JC2021027)Research Project of the Nantong Health Commission(QN2022044).
文摘Vibrio parahaemolyticus,a gram-negative halophilic bacterium that naturally inhabits coastal waters,causes gastroenteritis,skin infections,and septicemia in human beings[1].This bacterium produces multiple virulence factors,including thermostable direct hemolysin(TDH),TDH-related hemolysin(TRH),type Ⅲ secretion system 1(T3SS1),T3SS2,type Ⅵ secretion system 1(T6SS1),and T6SS2[1].Furthermore,Ⅴ.parahaemolyticus forms biofilms on the surface,which help it in adapting to unfavorable conditions[2].Mature biofilm formation requires special structures,including lateral and polar flagella,exopolysaccharide(EPS),and type Ⅳ pili[2].
