To remain competitive,proteobacteria use various contact-dependent weapon systems to defend against microbial com-petitors.The bacterial-killing type IV secretion system(T4SS)is one such powerful weapon.It commonly co...To remain competitive,proteobacteria use various contact-dependent weapon systems to defend against microbial com-petitors.The bacterial-killing type IV secretion system(T4SS)is one such powerful weapon.It commonly controls the killing/competition between species by secreting the lethal T4SS effector(T4E)proteins carrying conserved XVIPCD domains into competing cells.In this study,we sought knowledge to understand whether the bacterial-killing T4SS-producing bacteria encode T4E-like proteins and further explore their biological functions.To achieve this,we designed a T4E-guided approach to discover T4E-like proteins that are designated as atypical T4Es.Initially,this approach required scientists to perform simple BlastP search to identify T4E homologs that lack the XVIPCD domain in the genomes of T4SS-producing bacteria.These homologous genes were then screened in Escherichia coli to identify antibacterial candidates(atypical T4Es)and their neighboring detoxification proteins,followed by testing their gene cotranscription and validating their physical interactions.Using this approach,we did discover two atypical T4E proteins from the plant-beneficial Lysobacter enzymogenes and the phytopathogen Xanthomonas citri.We also provided substantial evidence to show that the atypical T4E protein Le1637-mediated bacterial defense in interspecies interactions between L.enzymogenes and its competitors.Therefore,the newly designed T4E-guided approach holds promise for detecting functional atypical T4E proteins in bacterial cells.展开更多
目的建立针对高致病性2型猪链球菌（Streptococcus suis 2，SS2）89K毒力岛Ⅳ型分泌系统的环介导等温扩增（100p-mediated isothermal amplification，LAMP）方法。方法根据国内流行株特有89K毒力岛编码的Ⅳ型分泌系统（T4SS-89K）的vir...目的建立针对高致病性2型猪链球菌（Streptococcus suis 2，SS2）89K毒力岛Ⅳ型分泌系统的环介导等温扩增（100p-mediated isothermal amplification，LAMP）方法。方法根据国内流行株特有89K毒力岛编码的Ⅳ型分泌系统（T4SS-89K）的virB4-89K基因保守区域设计并合成LAMP引物，通过优化反应体系和扩增条件建立T4SS-89K快速检测方法，对方法的特异性、敏感性进行评估。结果优化的LAMP反应体系具有良好的扩增效率，检测灵敏度为1．53×10^-1拷贝／反应，全部扩增检测可在60rain内完成；建立的LAMP法具有良好的特异性，与不含T4SS-89K的猪链球菌（包括1／2型、1型、3-33型），以及其他常见9种对照菌均不发生特异性扩增，而与1998和2005年疫情现场分离的高致病性SS2均可发生特异性扩增。结论建立的LAMP方法具有特异、灵敏，设备要求简单等特点，可用于高致病性SS2快速检测。展开更多
Helicobacter pylori(H. pylori) is perhaps the most ubiquitous and successful human pathogen, since it colonizes the stomach of more than half of humankind. Infection with this bacterium is commonly acquired during chi...Helicobacter pylori(H. pylori) is perhaps the most ubiquitous and successful human pathogen, since it colonizes the stomach of more than half of humankind. Infection with this bacterium is commonly acquired during childhood. Once infected, people carry the bacteria for decades or even for life, if not treated. Persistent infection with this pathogen causes gastritis, peptic ulcer disease and is also strongly associated with the development of gastric cancer. Despite induction of innate and adaptive immune responses in the infected individual, the host is unable to clear the bacteria. One widely accepted hallmark of H. pylori is that it successfully and stealthily evades host defense mechanisms. Though the gastric mucosa is well protected against infection, H. pylori is able to reside under the mucus, attach to gastric epithelial cells and cause persistent infection by evading immune responses mediated by host. In this review, we discuss how H. pylori avoids innate and acquired immune response elements, uses gastric epithelial cells as mediators to manipulate host T cell responses and uses virulence factors to avoid adaptive immune responses by T cells to establish a persistent infection. We also discuss in this review how the genetic diversity of this pathogen helps for its survival.展开更多
整合性接合元件(Integrative and conjugative elements,ICEs)主要介导原核生物间遗传信息的横向基因交换,在细菌毒性、耐药性、抗重金属等特性传播上发挥关键作用。ICEs的水平转移极大地加速了抗性基因在同种及不同种属之间的传播,造...整合性接合元件(Integrative and conjugative elements,ICEs)主要介导原核生物间遗传信息的横向基因交换,在细菌毒性、耐药性、抗重金属等特性传播上发挥关键作用。ICEs的水平转移极大地加速了抗性基因在同种及不同种属之间的传播,造成细菌的耐药以至多重耐药问题日益严重,耐药机制日趋复杂;同时ICEs的接合转移过程受细菌Ⅳ型分泌系统(Type Ⅳ secretion system,T4SS)影响。本文着重从ICEs的基因结构、接合转移过程以及T4SS组成元件的结构进行概述,并对T4SS各组件间相互作用的研究进展进行了初步探讨。展开更多
Plant growth-promoting rhizobacteria(PGPR)contain various biocontrol bacteria with broad-spectrum antimicrobial activity,and their single species has been extensively applied to control crop diseases.The development o...Plant growth-promoting rhizobacteria(PGPR)contain various biocontrol bacteria with broad-spectrum antimicrobial activity,and their single species has been extensively applied to control crop diseases.The development of complex biocontrol community by mixing two or more PGPR members together is a promising strategy to enlarge the efficacy and scope of biocontrol.However,an effective method to assess the natural compatibility of PGPR members has not yet been established to date.Here,we developed such a tool by using the bacterial contactdependent antibacterial activity(CDAA)as a probe.We showed that the CDAA events are common in two-species interactions in the four selected representative PGPRs,represented by the incompatible interaction of Lysobacter enzymogenes strain OH11(OH11)and Lysobacter antibioticus strain OH13(OH13).We further showed that the CDAA between OH11 and OH13 is jointly controlled by a contact-dependent killing device,called the type IV secretion system(T4SS).By deleting the respective T4SS synthesis genes,the T4SS in both strains was co-inactivated and this step unlocked their natural CDAA,resulting in an engineered,compatible mutant alliance that co-displayed antibacterial and antifungal activity.Therefore,this study reveals that releasing bacterial CDAA is effective to rationally engineer the biocontrol community.展开更多
To facilitate survival,replication,and dissemination,the intracellular pathogen Legionella pneumophila relies on its unique type IVB secretion system(T4SS)to deliver over 330 effectors to hijack host cell pathways in a...To facilitate survival,replication,and dissemination,the intracellular pathogen Legionella pneumophila relies on its unique type IVB secretion system(T4SS)to deliver over 330 effectors to hijack host cell pathways in a spatiotemporal manner.The effectors and their host targets are largely unexplored due to their low sequence identity to the known proteins and functional redundancy.The T4SS effector SidN(Lpg1083)is secreted into host cells during the late infection period.However,to the best of our knowledge,the molecular characterization of SidN has not been studied.Herein,we identified SidN as a nuclear envelope-localized effector.Its structure adopts a novel fold,and the N-terminal domain is crucial for its specific subcellular localization.Furthermore,we found that SidN is transported by eukaryotic karyopherin Importin-13 into the nucleus,where it attaches to the N-terminal region of Lamin-B2 to interfere with the integrity of the nuclear envelope,causing nuclear membrane disruption and eventually cell death.Our work provides new insights into the structure and function of an L.pneumophila effector protein,and suggests a potential strategy utilized by the pathogen to promote host cell death and then escape from the host for secondary infection.展开更多
基金the National Natural Science Foundation of China(U22A20486,32072470 to G.Q.)the Natural Key Research and Development Program(2022YFD1400200 to G.Q.)+1 种基金Science and Technology project of Shanxi Branch of China National Tobacco Corporation(KJ‐2022‐04)the Jiangsu University advantage discipline construction project(80900246 to X.S.)。
文摘To remain competitive,proteobacteria use various contact-dependent weapon systems to defend against microbial com-petitors.The bacterial-killing type IV secretion system(T4SS)is one such powerful weapon.It commonly controls the killing/competition between species by secreting the lethal T4SS effector(T4E)proteins carrying conserved XVIPCD domains into competing cells.In this study,we sought knowledge to understand whether the bacterial-killing T4SS-producing bacteria encode T4E-like proteins and further explore their biological functions.To achieve this,we designed a T4E-guided approach to discover T4E-like proteins that are designated as atypical T4Es.Initially,this approach required scientists to perform simple BlastP search to identify T4E homologs that lack the XVIPCD domain in the genomes of T4SS-producing bacteria.These homologous genes were then screened in Escherichia coli to identify antibacterial candidates(atypical T4Es)and their neighboring detoxification proteins,followed by testing their gene cotranscription and validating their physical interactions.Using this approach,we did discover two atypical T4E proteins from the plant-beneficial Lysobacter enzymogenes and the phytopathogen Xanthomonas citri.We also provided substantial evidence to show that the atypical T4E protein Le1637-mediated bacterial defense in interspecies interactions between L.enzymogenes and its competitors.Therefore,the newly designed T4E-guided approach holds promise for detecting functional atypical T4E proteins in bacterial cells.
文摘目的建立针对高致病性2型猪链球菌（Streptococcus suis 2，SS2）89K毒力岛Ⅳ型分泌系统的环介导等温扩增（100p-mediated isothermal amplification，LAMP）方法。方法根据国内流行株特有89K毒力岛编码的Ⅳ型分泌系统（T4SS-89K）的virB4-89K基因保守区域设计并合成LAMP引物，通过优化反应体系和扩增条件建立T4SS-89K快速检测方法，对方法的特异性、敏感性进行评估。结果优化的LAMP反应体系具有良好的扩增效率，检测灵敏度为1．53×10^-1拷贝／反应，全部扩增检测可在60rain内完成；建立的LAMP法具有良好的特异性，与不含T4SS-89K的猪链球菌（包括1／2型、1型、3-33型），以及其他常见9种对照菌均不发生特异性扩增，而与1998和2005年疫情现场分离的高致病性SS2均可发生特异性扩增。结论建立的LAMP方法具有特异、灵敏，设备要求简单等特点，可用于高致病性SS2快速检测。
基金Supported by National Institutes of Health grants K22AI68712,R56DK090090-01American Gastroenterological Association Research Scholar Award,NIH 1U54RR02614+3 种基金The University of Texas Medical Branch Clinical and Translational Sciences AwardThe American cancer society RSG-10-159-01-LIB,NIH 8UL1TR000041The University of New Mexico clinical and Translational Science CenterTaslima T Lina is funded by Sealy Centre for Vaccine Development Pre-doctoral fellowship and McLaughlin Pre-doctoral Fellowship,UTMB
文摘Helicobacter pylori(H. pylori) is perhaps the most ubiquitous and successful human pathogen, since it colonizes the stomach of more than half of humankind. Infection with this bacterium is commonly acquired during childhood. Once infected, people carry the bacteria for decades or even for life, if not treated. Persistent infection with this pathogen causes gastritis, peptic ulcer disease and is also strongly associated with the development of gastric cancer. Despite induction of innate and adaptive immune responses in the infected individual, the host is unable to clear the bacteria. One widely accepted hallmark of H. pylori is that it successfully and stealthily evades host defense mechanisms. Though the gastric mucosa is well protected against infection, H. pylori is able to reside under the mucus, attach to gastric epithelial cells and cause persistent infection by evading immune responses mediated by host. In this review, we discuss how H. pylori avoids innate and acquired immune response elements, uses gastric epithelial cells as mediators to manipulate host T cell responses and uses virulence factors to avoid adaptive immune responses by T cells to establish a persistent infection. We also discuss in this review how the genetic diversity of this pathogen helps for its survival.
文摘Plant growth-promoting rhizobacteria(PGPR)contain various biocontrol bacteria with broad-spectrum antimicrobial activity,and their single species has been extensively applied to control crop diseases.The development of complex biocontrol community by mixing two or more PGPR members together is a promising strategy to enlarge the efficacy and scope of biocontrol.However,an effective method to assess the natural compatibility of PGPR members has not yet been established to date.Here,we developed such a tool by using the bacterial contactdependent antibacterial activity(CDAA)as a probe.We showed that the CDAA events are common in two-species interactions in the four selected representative PGPRs,represented by the incompatible interaction of Lysobacter enzymogenes strain OH11(OH11)and Lysobacter antibioticus strain OH13(OH13).We further showed that the CDAA between OH11 and OH13 is jointly controlled by a contact-dependent killing device,called the type IV secretion system(T4SS).By deleting the respective T4SS synthesis genes,the T4SS in both strains was co-inactivated and this step unlocked their natural CDAA,resulting in an engineered,compatible mutant alliance that co-displayed antibacterial and antifungal activity.Therefore,this study reveals that releasing bacterial CDAA is effective to rationally engineer the biocontrol community.
基金supported by grants from the National Natural Science Foundation of China(31970103 to H.G.and 32071158 to X.Q.)China Postdoctoral Science Foundation(2021M700178 to X.C.)the Natural Science Foundation of Department of Education of Anhui Province(K120462017 to X.C.).
文摘To facilitate survival,replication,and dissemination,the intracellular pathogen Legionella pneumophila relies on its unique type IVB secretion system(T4SS)to deliver over 330 effectors to hijack host cell pathways in a spatiotemporal manner.The effectors and their host targets are largely unexplored due to their low sequence identity to the known proteins and functional redundancy.The T4SS effector SidN(Lpg1083)is secreted into host cells during the late infection period.However,to the best of our knowledge,the molecular characterization of SidN has not been studied.Herein,we identified SidN as a nuclear envelope-localized effector.Its structure adopts a novel fold,and the N-terminal domain is crucial for its specific subcellular localization.Furthermore,we found that SidN is transported by eukaryotic karyopherin Importin-13 into the nucleus,where it attaches to the N-terminal region of Lamin-B2 to interfere with the integrity of the nuclear envelope,causing nuclear membrane disruption and eventually cell death.Our work provides new insights into the structure and function of an L.pneumophila effector protein,and suggests a potential strategy utilized by the pathogen to promote host cell death and then escape from the host for secondary infection.
