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
Objective Pseudomonas aeruginosa is a ubiquitous and opportunistic pathogen that uses the type Ⅲ secretion system （TTSS） to inject effector proteins directly into the cytosol of target cells to subvert the host cel...Objective Pseudomonas aeruginosa is a ubiquitous and opportunistic pathogen that uses the type Ⅲ secretion system （TTSS） to inject effector proteins directly into the cytosol of target cells to subvert the host cell＇s functions. Specialized bacterial chaperones are required for effective secretion of some effectors. To identify the chaperone of ExoS, the representative effector secreted by the TTSS of P aeruginosa, we analyzed the role of a postulated chaperone termed Orfl. Methods By allelic exchange, we constructed the mutant with the deletion of gene Orfl. Analysis of secreted and cell-associated fractions was performed by SDS-PAGE and Western blotting. Using strain expressing in trans Orfl, tagged by V5 polypeptide and histidine, protein-protein interaction was determined by affinity resin pull-down assay in combination with MALDI-TOF The role of Orfl in the expression of exoS was evaluated by gene reporter analysis. Results Pull-down assay showed that Orfl binds to ExoS and ExoT. Secretion profile analysis showed that Orfl was necessary for the optimal secretion of ExoS and ExoT. However, Orfl had no effect on the expression of exoS. Conclusion Orfl is important for the secretion of ExoS probably by maintaining ExoS in a secretion-competent conformation. We propose to name Orfl as SpcS for ＂specific Pseudomonas chaperone for ExoS＂.展开更多
In order to enrich the research about type III secretion system （T3SS） injectisome of Vibrio alginolyticus, vscX gene was cloned from E algianlyticus strain HY9901 for bioinformatics analysis and expression analysis...In order to enrich the research about type III secretion system （T3SS） injectisome of Vibrio alginolyticus, vscX gene was cloned from E algianlyticus strain HY9901 for bioinformatics analysis and expression analysis. Specific primers were designed according to the full-length geanme sequence of V. alginolyticus in GenBank. vscX gene （C, enBank accession number： FR780679） contained a 378 bp open reading frame （ORF）, encoding a putative protein of 125 amino acids. The theoretical molecular weight was 14.209 2 kD and theoretical pI was 5.75. By using Signal 4.1 Server and TMHMM Server 2.0, it was predicted that VscX protein had no transmembrane domain or signal peptide. The results of prediction using SoftBerry-Psite software showed that VscX protein contained three casein ki- nase lI phosphorylation sites, one N-myristoylation site and three C-terminal targeting signal sites. Subcellular localization revealed that VscX might be located in cytoplasm with the possibility of 56.5%. According to SMART prediction, VscX had one Pfam （ 1 - 125 aa） domain. Phylogenetic analysis revealed that VscX from V. alginolyticus and VscX from E parahemolyticus were clustered into the same group. Network interaction analysis showed that vscX was adjacent to vseY, vopB and sycN. By real-time fluorescent quantitative PCR technique and 2-△△△ method, the differences in expression levels of VscX mRNA in V. alginolyticus strain HY9901, T3SS deletion strain AvscO and complementary strain C-vscO at different growth stages were analyzed. The results showed that the expression levels of VscX mRNA in V. algianlyticus strain HY9901 and C-vscO were significantly up-regulated at stable growth stage （ P 〈0.01 ） ; the expression levels of VscX mRNA in deletion strain △vscO were significantly up-regulated at late growth stage （ P 〈0.01 ）. This study provided the basis for revealing the transport mechanism of T3SS injectisome of E alginolyticus.展开更多
Secretion systems, macromolecules to pass which can mediate the across cellular membranes, are essential for virulent and genetic material exchange among bacterial species[1]. Type IV secretion system （T4SS） is one ...Secretion systems, macromolecules to pass which can mediate the across cellular membranes, are essential for virulent and genetic material exchange among bacterial species[1]. Type IV secretion system （T4SS） is one of the secretion systems and it usually consists of 12 genes： VirB1, VirB2 ...VirB11, and VirD4[2]. The structure and molecular mechanisms of these genes have been well analyzed in Gram-negative strains[3] and Gram-positive strains were once believed to be lack of T4SS. However, some recent studies revealed that one or more virB/D genes also exist in some kinds of Gram-positive bacteria and play similar role, and form a T4SS-like system[3]. The VirBl-like, VirB4, VirB6, and VirD4 genes were identified in the chromosome of Gram-positive bacterium Streptococcus suis in our previous studies and their role as important mobile elements for horizontal transfer to recipients in an 89 K pathogenicity island （PAl） was demonstrated[45]. However, their structure and molecular mechanisms in other strains, especially in Gram-positive strains, are remained unclear.展开更多
Toxin–antitoxin(TA)systems,which are prevalent in bacteria and archaea,play diverse roles in bacterial physiology and have been proposed to be significant in stress adaptation.Despite the extensive characterization o...Toxin–antitoxin(TA)systems,which are prevalent in bacteria and archaea,play diverse roles in bacterial physiology and have been proposed to be significant in stress adaptation.Despite the extensive characterization of numerous TA systems in various bacteria,the investigation of these systems within Streptococcus suis is still limited.Here,we systematically analyzed the type Ⅱ TA systems of 95 S.suis genomes available in the GenBank database using TAfinder.A total of 612 putative type Ⅱ TA systems were retrieved and classified into 10 categories by phylogenetic analysis.Notably,an elevated occurrence of these TA systems was observed among the important prevalent serotypes 2,4,5,9,14,Chz,NCL1,and NCL3 strains.The following study identified the activities of TA systems using 2 strategies and confirmed the regulatory effect of HigBA on the type Ⅶ secretion system in S.suis by measuringβ-galactosidase activity and transcriptional changes.Moreover,we unveiled a hitherto uncharacterized,highly prevalent novel TA system,with the composition of antitoxin–toxin–antitoxin(SS-ATA),which regulates the downstream two-component signaling system.Altogether,this study systematically analyzed the type Ⅱ TA systems within S.suis,highlighting the widespread distribution of Hig BA and SS-ATA as important regulatory elements in S.suis.展开更多
Ralstonia solanacearum is a widespread plant bacterial pathogen that can launch a range of type Ⅲ effectors(T3Es)to cause disease.In this study,we isolate a pathogenic R.solanacearum strain named P380 from tomato rhi...Ralstonia solanacearum is a widespread plant bacterial pathogen that can launch a range of type Ⅲ effectors(T3Es)to cause disease.In this study,we isolate a pathogenic R.solanacearum strain named P380 from tomato rhizosphere.Five out of 12 core T3Es of strain P380 are introduced into Pseudomonas syringae DC3000D36E separately to determine their functions in interacting with plants.DC3000D36E that harbors each effector suppresses FliC-triggered Pti5 and ACRE31 expression,ROS burst,and callose deposition.RipAE,RipU,and RipW elicit cell death as well as upregulate the MAPK cascades in Nicotiana benthamiana.The derivatives RipC1^(△DDXDX(T/V))and RipW^(△DDKXXQ)but not RipAE^(K310R) fail to suppress ROS burst.Moreover,RipAE^(K310R) and RipW^(△DDKXXQ) retain the cell death elicitation ability.RipAE and RipW are associated with salicylic acid and jasmonic acid pathways,respectively.RipAE and RipAQ significantly promote the propagation of DC3000D36E in plants.The five core T3Es localize in diverse subcellular organelles of nucleus,plasma membrane,endoplasmic reticulum,and Golgi network.The suppressor of G2 allele of Skp1 is required for RipAE but not RipU-triggered cell death in N.benthamiana.These results indicate that the core T3Es in R.solanacearum play diverse roles in plantpathogen interactions.展开更多
Lysobacter enzymogenes is less-studied, but emerging as a powerful biocontrol bacterium producing multiple antimicrobial weapons including lytic enzymes, toxins, secondary metabolites and protein secretion systems.The...Lysobacter enzymogenes is less-studied, but emerging as a powerful biocontrol bacterium producing multiple antimicrobial weapons including lytic enzymes, toxins, secondary metabolites and protein secretion systems.The loss of surface-attached flagellum, production of heat-stable antifungal factor(HSAF, also named as Ningrongmycin) as a novel antifungal antibiotic, and the use of the type Ⅳ secretion system(T4SS) rather than the common type Ⅵ secretion system(T6SS) to kill competitor bacteria make this species unique. These distinct features set L. enzymogenes apart from well-studied plant beneficial biocontrol agents, such as Bacillus and Pseudomonas. This review describes what takes L. enzymogenes to be a unique biocontrol warrior by focusing to illustrate how the lack of flagellum governs morphological and functional co-adaptability, what adapted signaling transduction pathways are adopted to coordinate the biosynthesis of HSAF, and how to ecologically adapt plant rhizosphere by cell-to-cell interacting with microbiome members via the bacterial-killing T4SS.展开更多
Xanthomonas oryzae pv.oryzae(Xoo)causes bacterial blight in rice,which reduces crop yield and leads to significant economic losses.Bacterial sigma(σ)factors are highly specialized proteins that allow RNA polymerase t...Xanthomonas oryzae pv.oryzae(Xoo)causes bacterial blight in rice,which reduces crop yield and leads to significant economic losses.Bacterial sigma(σ)factors are highly specialized proteins that allow RNA polymerase to recognize and bind to specific promoters.σ^(70) factors also regulate the expression of genes involved in stress response and virulence.However,the role of RpoD in Xoo is still unclear.In this study,we found thatσ^(70) factor RpoD is quite conservative among phytopathogenic bacteria,especially in Xanthomonas sp.In Xoo,PXO_RpoD plays an important role in oxidative stress tolerance and cell motility,as well as being essential for full virulence.Cleavage under targets and tagmentation(CUT&Tag)analyses indicated that RpoD mediates the type three secretion system(T3SS)by regulating the regulation of hrpG and hrpX.By performing bacterial one-hybrid and electrophoretic mobility assay(EMSA),we observed that RpoD directly bound to the promoters of hrpG and hrpX.Collectively,these results demonstrate the transcriptional mechanism and pathogenic functions of RpoD in regulating cell motility and oxidative stress response,providing novel insights into potential targets for disease control.展开更多
The incidence of plant bacterial diseases has been rising annually alongside the development of facility agriculture,which can seriously affect the yield and quality of crops,and cause significant losses to agricultur...The incidence of plant bacterial diseases has been rising annually alongside the development of facility agriculture,which can seriously affect the yield and quality of crops,and cause significant losses to agricultural production globally.Thus,the development of highly effective prevention and control agents targeting plant pathogenic bacteria are urgently needed.The Type III secretion system(T3SS)is a complex molecular apparatus exist in many Gram-negative pathogenic bacteria,which plays a crucial role in the pathogenic process of bacteria.In recent years,T3SS has become an important target for the development of novel antibacterial agents.Here,we highlight the recent findings on a plant defense compound targeting T3SS for plant bacterial diseases by Lei and his colleagues.展开更多
Helicobacter pylori(H.pylori)colonizes the stomach of humans and causes chronic infection.The majority of bacteria live in the mucus layer overlying the gastric epithelial cells and only a small proportion of bacteria...Helicobacter pylori(H.pylori)colonizes the stomach of humans and causes chronic infection.The majority of bacteria live in the mucus layer overlying the gastric epithelial cells and only a small proportion of bacteria are found interacting with the epithelial cells.The bacteria living in the gastric mucus may act as a reservoir of infection for the underlying cells which is essential for the development of disease.Colonization of gastric mucus is likely to be key to the establishment of chronic infection.How H.pylori manages to colonise and survive in the hostile environment of the human stomach and avoid removal by mucus flow and killing by gastric acid is the subject of this review.We also discuss how bacterial and host factors may together go some way to explaining the susceptibility to colonization and the outcome of infection in different individuals.H.pylori infection of the gastric mucosa has become a paradigm for chronic infection.Understanding of why H.pylori is such a successful pathogen may help us understand how other bacterial species colonise mucosal surfaces and cause disease.展开更多
Objective To review the research progress on Type Ⅳ secretion system （T4SS） in HelicobacterpylorL Data sources The data used in this review were identified by searching of PUBMED （1995-2007） online resources usin...Objective To review the research progress on Type Ⅳ secretion system （T4SS） in HelicobacterpylorL Data sources The data used in this review were identified by searching of PUBMED （1995-2007） online resources using the key terms ＇Type Ⅳ secretion system＇ and ＇Helicobacter pylon. Study selection Mainly original articles and critical reviews written by major pioneer investigators of this field were selected. Results The research progress on T4SS in Helicobacter pylori was summarized. The structure and function was discussed. Conclusions T4SS is not only involved in toxin secretion and injection of virulence factors into eukaryotic host target cells, but also involved in horizontal DNA transfer to other bacteria and eukaryotic cells, through DNA uptake from or release into the extracellular milieu. It provides a new insight into the pathogenicity of Helicobacter pylori and a novel target for antimicrobials development. However, many challenges remain for us in understanding the biological role of T4SS in Helicobacter pylori.展开更多
Bacteria inhabit diverse and dynamic environments,where nutrients may be limited and toxic chemicals can be prevalent.To adapt to these stressful conditions,bacteria have evolved specialized protein secretion systems,...Bacteria inhabit diverse and dynamic environments,where nutrients may be limited and toxic chemicals can be prevalent.To adapt to these stressful conditions,bacteria have evolved specialized protein secretion systems,such as the type VI secretion system(T6SS)to facilitate their survival.As a molecular syringe,the T6SS expels various effectors into neighboring bacterial cells,eukaryotic cells,or the extracellular environment.These effectors improve the competitive fitness and environmental adaption of bacterial cells.Although primarily recognized as antibacterial weapons,recent studies have demonstrated that T6SSs have functions beyond interspecies competition.Here,we summarize recent research on the role of T6SSs in microbiome modulation,pathogenesis,and stress resistance.展开更多
TypeⅥSecretion System(T6SS)plays significant roles in microbial activities via injecting effectors into adjacent cells or environments.T6SS increasingly gained attention due to its important influence on pathogenesis...TypeⅥSecretion System(T6SS)plays significant roles in microbial activities via injecting effectors into adjacent cells or environments.T6SS increasingly gained attention due to its important influence on pathogenesis,microbial competition,etc.T6SS-associated research is explosively expanding on numerous grounds that call for an efficient resource.The SecReT6 version3 provides comprehensive information on T6SS and the interactions between T6SS and T6SS-related proteins such as T6SS regulators and T6SS effectors.To assist T6SS researches like microbial competition and regulatory mechanisms,SecReT6 v3developed online tools for detection and analysis of T6SS and T6SS-related proteins and estimation of T6SS-dependent killing risk.We have identified a novel T6SS regulator and T6SS-dependent killing capacity in Acinetobacter baumannii clinical isolates with the aid of SecReT6 v3.17,212 T6SSs and plentiful T6SS-related proteins in 26,573 bacterial complete genomes were also detected,analyzed and incorporated into the database.The database is freely available at https://bioinfo-mml.sjtu.edu.cn/SecReT6/.展开更多
Bacteria can evolve rapidly by acquiring new traits such as virulence,metabolic properties,and most importantly,antimicrobial resistance,through horizontal gene transfer(HGT).Multidrug resistance in bacteria,especiall...Bacteria can evolve rapidly by acquiring new traits such as virulence,metabolic properties,and most importantly,antimicrobial resistance,through horizontal gene transfer(HGT).Multidrug resistance in bacteria,especially in Gram-negative organisms,has become a global public health threat often through the spread of mobile genetic elements.Conjugation represents a major form of HGT and involves the transfer of DNA from a donor bacterium to a recipient by direct contact.Conjugative plasmids,a major vehicle for the dissemination of antimicrobial resistance,are selfish elements capable of mediating their own transmission through conjugation.To spread to and survive in a new bacterial host,conjugative plasmids have evolved mechanisms to circumvent both host defense systems and compete with co-resident plasmids.Such mechanisms have mostly been studied in model plasmids such as the F plasmid,rather than in conjugative plasmids that confer antimicrobial resistance(AMR)in important human pathogens.A better understanding of these mechanisms is crucial for predicting the flow of antimicrobial resistance-conferring conjugative plasmids among bacterial populations and guiding the rational design of strategies to halt the spread of antimicrobial resistance.Here,we review mechanisms employed by conjugative plasmids that promote their transmission and establishment in Gram-negative bacteria,by following the life cycle of conjugative plasmids.展开更多
[Objectives]The purpose was to investigate the function and mechanism of exsA gene in type III secretion system of Vibrio alginolyticus.[Methods]The full length of exsA was cloned using molecular biology techniques to...[Objectives]The purpose was to investigate the function and mechanism of exsA gene in type III secretion system of Vibrio alginolyticus.[Methods]The full length of exsA was cloned using molecular biology techniques to analyze its biological information.Fluorescence quantitative PCR technology was used to analyze the expression of exsA after different media stress.[Results]The exsA gene contains an open reading frame(ORF)of 861 bp,encoding 286 amino acids.The physico-chemical analysis shows that the molecular structural formula is C1442H2267N393O441S12,the theoretical molecular weight is 32.549 kD,the theoretical pI value is 6.0,and the protein is non-hydrophilic and unstable.The gene does not contain a transmembrane region,and there is no obvious signal peptide.The prediction result of protein subcellular localization shows that the protein is inside the cell.The deduced amino acid sequence and constructed phylogenetic tree show that V.alginolyticus has a close relationship with Vibrio antiquarius.The qPCR results show that the expression level of exsA in different media is different,highest in TSB medium containing bile salts,followed by DMEM medium,and lowest in ordinary TSB medium.[Conclusions]The gene sequence,molecular structure and isoelectric point of exsA,as well as its expression in three different media were obtained.展开更多
In this paper, the hopPmaJ gene, which encodes type III effector HopPmaJ of Vibrio alginolyticus, was cloned, sequenced and bioinformatically predicted. The results showed that hopPmaJ （GenBank accession number： KX2...In this paper, the hopPmaJ gene, which encodes type III effector HopPmaJ of Vibrio alginolyticus, was cloned, sequenced and bioinformatically predicted. The results showed that hopPmaJ （GenBank accession number： KX245315） is 345 bp in length and encodes 114 amino acids, with a theoretical molecular mass of 12. 774 kD, and a pI of 4.45. The protein has multiple functional domains and binding sites, but no signal peptide. The tertiary structure of the protein is a homodimer. Based on multiple parameters, the possible dominant B cell antigenic epitopes of HopPmaJ were predicted to be at positions 13 - 16, 29 -30, 40 -42, 45 -49 and 84 -91.展开更多
The type Ⅵ secretion system(T6SS)is a widespread protein secretion apparatus deployed by many Gram-negative bacterial species to interact with competitor bacteria,host organisms,and the environment.Yersinia pseudotub...The type Ⅵ secretion system(T6SS)is a widespread protein secretion apparatus deployed by many Gram-negative bacterial species to interact with competitor bacteria,host organisms,and the environment.Yersinia pseudotuber-culosis T6SS4 was recently reported to be involved in manganese acquisition;however,the underlying regulatory mechanism still remains unclear.In this study,we discovered that T6SS4 is regulated by ferric uptake regulator(Fur)in response to manganese ions(Mn^(2+)),and this negative regulation of Fur was proceeded by specifically recogniz-ing the promoter region of T6SS4 in Y.pseudotuberculosis.Furthermore,T6SS4 is induced by low Mn^(2+)and oxidative stress conditions via Fur,acting as a Mn^(2+)-responsive transcriptional regulator to maintain intracellular manganese homeostasis,which plays important role in the transport of Mn^(2+)for survival under oxidative stress.Our results pro-vide evidence that T6SS4 can enhance the oxidative stress resistance and virulence for Y.pseudotuberculosis.This study provides new insights into the regulation of T6SS4 via the Mn^(2+)-dependent transcriptional regulator Fur,and expands our knowledge of the regulatory mechanisms and functions of T6SS from Y.pseudotuberculosis.展开更多
Objective:To investigate the frequency of exoU and exoY genes in patients with Pseudomonas aeruginosa infection.Methods:In this study,100 clinical isolates of Pseudomonas aeruginosa were collected from patients hospit...Objective:To investigate the frequency of exoU and exoY genes in patients with Pseudomonas aeruginosa infection.Methods:In this study,100 clinical isolates of Pseudomonas aeruginosa were collected from patients hospitalized in educational-therapeutic hospitals and were identified using standard microbiological tests.Then,the antibiotic resistance pattern of the isolates was determined by the disk agar diffusion method.The bacterial DNAs were extracted by the alkaline lysis method.Finally,the presence of exoU and exoY genes was evaluated by the PCR test.Results:In this study,47%,72%,29%,39%,40%,and 44%of the isolates were non-susceptible to piperacillin,aztreonam,ceftazidime,imipenem,tobramycin,and ciprofloxacin,respectively.In addition,95%and 93%of the clinical isolates carried the exoU and exoY genes.Blood and fecal isolates had both virulence genes,while only one wound isolate had neither genes.Meanwhile,all urinary isolates contained the exoY gene and only one isolate lacked the exoU gene.Also,88 isolates simultaneously had both exoU and exoY genes.Conclusions:High prevalence of exoU and exoY genes in this region indicates a significant role of typeⅢsecretion system in pathogenesis of Pseudomonas aeruginosa.The typeⅢsecretion system may be a suitable target to reduce the pathogenicity of this bacterium.展开更多
Hydrazones of poorly studied fluorine-containing oxamic acid thiohydrazides were synthesized by the reaction with salicylaldehydes. Tests showed that the newly synthesized compounds were effective low-toxic inhibitors...Hydrazones of poorly studied fluorine-containing oxamic acid thiohydrazides were synthesized by the reaction with salicylaldehydes. Tests showed that the newly synthesized compounds were effective low-toxic inhibitors of type III secretion system in Chlamydia trachomatis.展开更多
Mycosin-1 protease(MycP1)is a serine protease anchored to the inner membrane of Mycobacterium tuberculosis,and is essential in virulence factor secretion through the ESX-1 type VII secretion system(T7SS).Bacterial phy...Mycosin-1 protease(MycP1)is a serine protease anchored to the inner membrane of Mycobacterium tuberculosis,and is essential in virulence factor secretion through the ESX-1 type VII secretion system(T7SS).Bacterial physiology studies demonstrated that MycP1 plays a dual role in the regulation of ESX-1 secretion and virulence,primarily through cleavage of its secretion substrate EspB.MycP1 contains a putative N-terminal inhibitory propeptide and a catalytic triad of Asp-His-Ser,classic hallmarks of a sub-tilase family serine protease.The MycP1 propeptide was previously reported to be initially inactive and activated after prolonged incubation.In this study,we have deter-mined crystal structures of MycP1 with(MycP124-422)and without(MycP1^(63-422))the propeptide,and conducted EspB cleavage assays using the two proteins.Very high struc-tural similarity was observed in the two crystal structures.Interestingly,protease assays demonstrated positive EspB cleavage for both proteins,indicating that the putative propeptide does not inhibit protease activity.Molecu-lar dynamic simulations showed higher rigidity in regions guarding the entrance to the catalytic site in MycP124-422 than in MycP1^(63-422),suggesting that the putative propeptide might contribute to the conformational stability of the active site cleft and surrounding regions.展开更多
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This research was supported by the association "Vaincre la Mucoviscidose" of France
文摘Objective Pseudomonas aeruginosa is a ubiquitous and opportunistic pathogen that uses the type Ⅲ secretion system （TTSS） to inject effector proteins directly into the cytosol of target cells to subvert the host cell＇s functions. Specialized bacterial chaperones are required for effective secretion of some effectors. To identify the chaperone of ExoS, the representative effector secreted by the TTSS of P aeruginosa, we analyzed the role of a postulated chaperone termed Orfl. Methods By allelic exchange, we constructed the mutant with the deletion of gene Orfl. Analysis of secreted and cell-associated fractions was performed by SDS-PAGE and Western blotting. Using strain expressing in trans Orfl, tagged by V5 polypeptide and histidine, protein-protein interaction was determined by affinity resin pull-down assay in combination with MALDI-TOF The role of Orfl in the expression of exoS was evaluated by gene reporter analysis. Results Pull-down assay showed that Orfl binds to ExoS and ExoT. Secretion profile analysis showed that Orfl was necessary for the optimal secretion of ExoS and ExoT. However, Orfl had no effect on the expression of exoS. Conclusion Orfl is important for the secretion of ExoS probably by maintaining ExoS in a secretion-competent conformation. We propose to name Orfl as SpcS for ＂specific Pseudomonas chaperone for ExoS＂.
基金Supported by National Natural Science Foundation of China(31402344,31572656)Major Program of Natural Science Foundation of Guangdong Province(2015A030308020)
文摘In order to enrich the research about type III secretion system （T3SS） injectisome of Vibrio alginolyticus, vscX gene was cloned from E algianlyticus strain HY9901 for bioinformatics analysis and expression analysis. Specific primers were designed according to the full-length geanme sequence of V. alginolyticus in GenBank. vscX gene （C, enBank accession number： FR780679） contained a 378 bp open reading frame （ORF）, encoding a putative protein of 125 amino acids. The theoretical molecular weight was 14.209 2 kD and theoretical pI was 5.75. By using Signal 4.1 Server and TMHMM Server 2.0, it was predicted that VscX protein had no transmembrane domain or signal peptide. The results of prediction using SoftBerry-Psite software showed that VscX protein contained three casein ki- nase lI phosphorylation sites, one N-myristoylation site and three C-terminal targeting signal sites. Subcellular localization revealed that VscX might be located in cytoplasm with the possibility of 56.5%. According to SMART prediction, VscX had one Pfam （ 1 - 125 aa） domain. Phylogenetic analysis revealed that VscX from V. alginolyticus and VscX from E parahemolyticus were clustered into the same group. Network interaction analysis showed that vscX was adjacent to vseY, vopB and sycN. By real-time fluorescent quantitative PCR technique and 2-△△△ method, the differences in expression levels of VscX mRNA in V. alginolyticus strain HY9901, T3SS deletion strain AvscO and complementary strain C-vscO at different growth stages were analyzed. The results showed that the expression levels of VscX mRNA in V. algianlyticus strain HY9901 and C-vscO were significantly up-regulated at stable growth stage （ P 〈0.01 ） ; the expression levels of VscX mRNA in deletion strain △vscO were significantly up-regulated at late growth stage （ P 〈0.01 ）. This study provided the basis for revealing the transport mechanism of T3SS injectisome of E alginolyticus.
基金supported by the National Natural Science Foundation of China (No. 81201322)the Priority Project on Infectious Disease Control and Prevention 2011ZX10004-001 and 2013ZX10003006-002 by the Chinese Ministry of Science and Technology and the Chinese Ministry of Healththe Foundation of State Key Laboratory for Infectious Disease Prevention and Control (Grand No. 2011SKLID303)
文摘Secretion systems, macromolecules to pass which can mediate the across cellular membranes, are essential for virulent and genetic material exchange among bacterial species[1]. Type IV secretion system （T4SS） is one of the secretion systems and it usually consists of 12 genes： VirB1, VirB2 ...VirB11, and VirD4[2]. The structure and molecular mechanisms of these genes have been well analyzed in Gram-negative strains[3] and Gram-positive strains were once believed to be lack of T4SS. However, some recent studies revealed that one or more virB/D genes also exist in some kinds of Gram-positive bacteria and play similar role, and form a T4SS-like system[3]. The VirBl-like, VirB4, VirB6, and VirD4 genes were identified in the chromosome of Gram-positive bacterium Streptococcus suis in our previous studies and their role as important mobile elements for horizontal transfer to recipients in an 89 K pathogenicity island （PAl） was demonstrated[45]. However, their structure and molecular mechanisms in other strains, especially in Gram-positive strains, are remained unclear.
基金supported by the National Key Research and Development Program of China(2022YFD1800904)the National Natural Science Foundation of China(31972650 and 32102673)+1 种基金the Postgraduate Research&Practice Innovation Program of Jiangsu Province,China(KYCX22_0780)the China Postdoctoral Science Foundation(2020M682297)。
文摘Toxin–antitoxin(TA)systems,which are prevalent in bacteria and archaea,play diverse roles in bacterial physiology and have been proposed to be significant in stress adaptation.Despite the extensive characterization of numerous TA systems in various bacteria,the investigation of these systems within Streptococcus suis is still limited.Here,we systematically analyzed the type Ⅱ TA systems of 95 S.suis genomes available in the GenBank database using TAfinder.A total of 612 putative type Ⅱ TA systems were retrieved and classified into 10 categories by phylogenetic analysis.Notably,an elevated occurrence of these TA systems was observed among the important prevalent serotypes 2,4,5,9,14,Chz,NCL1,and NCL3 strains.The following study identified the activities of TA systems using 2 strategies and confirmed the regulatory effect of HigBA on the type Ⅶ secretion system in S.suis by measuringβ-galactosidase activity and transcriptional changes.Moreover,we unveiled a hitherto uncharacterized,highly prevalent novel TA system,with the composition of antitoxin–toxin–antitoxin(SS-ATA),which regulates the downstream two-component signaling system.Altogether,this study systematically analyzed the type Ⅱ TA systems within S.suis,highlighting the widespread distribution of Hig BA and SS-ATA as important regulatory elements in S.suis.
基金supported by the National Key R&D Program of China(2019YFD1002000)the Science and Technology Programs of the Shandong Tobacco(KN273)Zunyi Tobacco(2021XM03).
文摘Ralstonia solanacearum is a widespread plant bacterial pathogen that can launch a range of type Ⅲ effectors(T3Es)to cause disease.In this study,we isolate a pathogenic R.solanacearum strain named P380 from tomato rhizosphere.Five out of 12 core T3Es of strain P380 are introduced into Pseudomonas syringae DC3000D36E separately to determine their functions in interacting with plants.DC3000D36E that harbors each effector suppresses FliC-triggered Pti5 and ACRE31 expression,ROS burst,and callose deposition.RipAE,RipU,and RipW elicit cell death as well as upregulate the MAPK cascades in Nicotiana benthamiana.The derivatives RipC1^(△DDXDX(T/V))and RipW^(△DDKXXQ)but not RipAE^(K310R) fail to suppress ROS burst.Moreover,RipAE^(K310R) and RipW^(△DDKXXQ) retain the cell death elicitation ability.RipAE and RipW are associated with salicylic acid and jasmonic acid pathways,respectively.RipAE and RipAQ significantly promote the propagation of DC3000D36E in plants.The five core T3Es localize in diverse subcellular organelles of nucleus,plasma membrane,endoplasmic reticulum,and Golgi network.The suppressor of G2 allele of Skp1 is required for RipAE but not RipU-triggered cell death in N.benthamiana.These results indicate that the core T3Es in R.solanacearum play diverse roles in plantpathogen interactions.
基金funded by the the Fundamental Research Funds for the Central Universities, China (RENCAI2024002 and KJJQ2024014)the Natural Key Research and Development Program of China (2022YFD1400200)the National Natural Science Foundation of China (U22A20486, 32072470, 32001955 and 32470112)
文摘Lysobacter enzymogenes is less-studied, but emerging as a powerful biocontrol bacterium producing multiple antimicrobial weapons including lytic enzymes, toxins, secondary metabolites and protein secretion systems.The loss of surface-attached flagellum, production of heat-stable antifungal factor(HSAF, also named as Ningrongmycin) as a novel antifungal antibiotic, and the use of the type Ⅳ secretion system(T4SS) rather than the common type Ⅵ secretion system(T6SS) to kill competitor bacteria make this species unique. These distinct features set L. enzymogenes apart from well-studied plant beneficial biocontrol agents, such as Bacillus and Pseudomonas. This review describes what takes L. enzymogenes to be a unique biocontrol warrior by focusing to illustrate how the lack of flagellum governs morphological and functional co-adaptability, what adapted signaling transduction pathways are adopted to coordinate the biosynthesis of HSAF, and how to ecologically adapt plant rhizosphere by cell-to-cell interacting with microbiome members via the bacterial-killing T4SS.
基金supported by the National Natural Science Foundation of China(32072379,32001865 and 32202259)。
文摘Xanthomonas oryzae pv.oryzae(Xoo)causes bacterial blight in rice,which reduces crop yield and leads to significant economic losses.Bacterial sigma(σ)factors are highly specialized proteins that allow RNA polymerase to recognize and bind to specific promoters.σ^(70) factors also regulate the expression of genes involved in stress response and virulence.However,the role of RpoD in Xoo is still unclear.In this study,we found thatσ^(70) factor RpoD is quite conservative among phytopathogenic bacteria,especially in Xanthomonas sp.In Xoo,PXO_RpoD plays an important role in oxidative stress tolerance and cell motility,as well as being essential for full virulence.Cleavage under targets and tagmentation(CUT&Tag)analyses indicated that RpoD mediates the type three secretion system(T3SS)by regulating the regulation of hrpG and hrpX.By performing bacterial one-hybrid and electrophoretic mobility assay(EMSA),we observed that RpoD directly bound to the promoters of hrpG and hrpX.Collectively,these results demonstrate the transcriptional mechanism and pathogenic functions of RpoD in regulating cell motility and oxidative stress response,providing novel insights into potential targets for disease control.
基金supported by the Key R&D Project of Hubei Province(2023BBB176)Wuhan Knowledge Innovation Special Project‘Dawning Program’(2023020201020433)the authors also gratefully acknowledge the partial support from Hubei Agricultural Science Innovation Center(2024-620-000-001-023).
文摘The incidence of plant bacterial diseases has been rising annually alongside the development of facility agriculture,which can seriously affect the yield and quality of crops,and cause significant losses to agricultural production globally.Thus,the development of highly effective prevention and control agents targeting plant pathogenic bacteria are urgently needed.The Type III secretion system(T3SS)is a complex molecular apparatus exist in many Gram-negative pathogenic bacteria,which plays a crucial role in the pathogenic process of bacteria.In recent years,T3SS has become an important target for the development of novel antibacterial agents.Here,we highlight the recent findings on a plant defense compound targeting T3SS for plant bacterial diseases by Lei and his colleagues.
基金Supported by A post graduate student grant awarded by Irish Research Council for Science Engineering and Technology(To Dunne C)an award from the Health Research Board Ireland(To Dolan B)a grant from Science Foundation Ireland,No.08/SRC/B1393
文摘Helicobacter pylori(H.pylori)colonizes the stomach of humans and causes chronic infection.The majority of bacteria live in the mucus layer overlying the gastric epithelial cells and only a small proportion of bacteria are found interacting with the epithelial cells.The bacteria living in the gastric mucus may act as a reservoir of infection for the underlying cells which is essential for the development of disease.Colonization of gastric mucus is likely to be key to the establishment of chronic infection.How H.pylori manages to colonise and survive in the hostile environment of the human stomach and avoid removal by mucus flow and killing by gastric acid is the subject of this review.We also discuss how bacterial and host factors may together go some way to explaining the susceptibility to colonization and the outcome of infection in different individuals.H.pylori infection of the gastric mucosa has become a paradigm for chronic infection.Understanding of why H.pylori is such a successful pathogen may help us understand how other bacterial species colonise mucosal surfaces and cause disease.
基金the Research Plan of Jiangsu Provincial Technology Commission (No.BS2004021)the Advanced Talent Research Plan of Jiangsu University(No.JDG2004008).
文摘Objective To review the research progress on Type Ⅳ secretion system （T4SS） in HelicobacterpylorL Data sources The data used in this review were identified by searching of PUBMED （1995-2007） online resources using the key terms ＇Type Ⅳ secretion system＇ and ＇Helicobacter pylon. Study selection Mainly original articles and critical reviews written by major pioneer investigators of this field were selected. Results The research progress on T4SS in Helicobacter pylori was summarized. The structure and function was discussed. Conclusions T4SS is not only involved in toxin secretion and injection of virulence factors into eukaryotic host target cells, but also involved in horizontal DNA transfer to other bacteria and eukaryotic cells, through DNA uptake from or release into the extracellular milieu. It provides a new insight into the pathogenicity of Helicobacter pylori and a novel target for antimicrobials development. However, many challenges remain for us in understanding the biological role of T4SS in Helicobacter pylori.
基金supported by the grant of the National Key R&D Program of China(2018YFA0901200)the National Natural Science Foundation of China(31725003,32070103,31860012 and 31800113).L.X.is supported by China Postdoctoral Science Foundation(2018 M631201)and Shaanxi Postdoctoral Science Foundation(2018BSHTDZZ20).
文摘Bacteria inhabit diverse and dynamic environments,where nutrients may be limited and toxic chemicals can be prevalent.To adapt to these stressful conditions,bacteria have evolved specialized protein secretion systems,such as the type VI secretion system(T6SS)to facilitate their survival.As a molecular syringe,the T6SS expels various effectors into neighboring bacterial cells,eukaryotic cells,or the extracellular environment.These effectors improve the competitive fitness and environmental adaption of bacterial cells.Although primarily recognized as antibacterial weapons,recent studies have demonstrated that T6SSs have functions beyond interspecies competition.Here,we summarize recent research on the role of T6SSs in microbiome modulation,pathogenesis,and stress resistance.
基金supported by the Science and Technology Commission of Shanghai Municipality(19430750600,19JC1413000)the National Natural Science Foundation of China(31670074)+1 种基金the Medical Excellence Award Funded by the Creative Research Development Grant from the First Affiliated Hospital of Guangxi Medical University(XK2019025)the Science Fund of the Republic of Serbia(7750294,q-bio BDS)。
文摘TypeⅥSecretion System(T6SS)plays significant roles in microbial activities via injecting effectors into adjacent cells or environments.T6SS increasingly gained attention due to its important influence on pathogenesis,microbial competition,etc.T6SS-associated research is explosively expanding on numerous grounds that call for an efficient resource.The SecReT6 version3 provides comprehensive information on T6SS and the interactions between T6SS and T6SS-related proteins such as T6SS regulators and T6SS effectors.To assist T6SS researches like microbial competition and regulatory mechanisms,SecReT6 v3developed online tools for detection and analysis of T6SS and T6SS-related proteins and estimation of T6SS-dependent killing risk.We have identified a novel T6SS regulator and T6SS-dependent killing capacity in Acinetobacter baumannii clinical isolates with the aid of SecReT6 v3.17,212 T6SSs and plentiful T6SS-related proteins in 26,573 bacterial complete genomes were also detected,analyzed and incorporated into the database.The database is freely available at https://bioinfo-mml.sjtu.edu.cn/SecReT6/.
基金the Wellcome Trust,BBSRC,and the National Natural Science Foundation of China(81802065,102908/Z/13/Z).
文摘Bacteria can evolve rapidly by acquiring new traits such as virulence,metabolic properties,and most importantly,antimicrobial resistance,through horizontal gene transfer(HGT).Multidrug resistance in bacteria,especially in Gram-negative organisms,has become a global public health threat often through the spread of mobile genetic elements.Conjugation represents a major form of HGT and involves the transfer of DNA from a donor bacterium to a recipient by direct contact.Conjugative plasmids,a major vehicle for the dissemination of antimicrobial resistance,are selfish elements capable of mediating their own transmission through conjugation.To spread to and survive in a new bacterial host,conjugative plasmids have evolved mechanisms to circumvent both host defense systems and compete with co-resident plasmids.Such mechanisms have mostly been studied in model plasmids such as the F plasmid,rather than in conjugative plasmids that confer antimicrobial resistance(AMR)in important human pathogens.A better understanding of these mechanisms is crucial for predicting the flow of antimicrobial resistance-conferring conjugative plasmids among bacterial populations and guiding the rational design of strategies to halt the spread of antimicrobial resistance.Here,we review mechanisms employed by conjugative plasmids that promote their transmission and establishment in Gram-negative bacteria,by following the life cycle of conjugative plasmids.
基金National Natural Science Foundation of China(32073015).
文摘[Objectives]The purpose was to investigate the function and mechanism of exsA gene in type III secretion system of Vibrio alginolyticus.[Methods]The full length of exsA was cloned using molecular biology techniques to analyze its biological information.Fluorescence quantitative PCR technology was used to analyze the expression of exsA after different media stress.[Results]The exsA gene contains an open reading frame(ORF)of 861 bp,encoding 286 amino acids.The physico-chemical analysis shows that the molecular structural formula is C1442H2267N393O441S12,the theoretical molecular weight is 32.549 kD,the theoretical pI value is 6.0,and the protein is non-hydrophilic and unstable.The gene does not contain a transmembrane region,and there is no obvious signal peptide.The prediction result of protein subcellular localization shows that the protein is inside the cell.The deduced amino acid sequence and constructed phylogenetic tree show that V.alginolyticus has a close relationship with Vibrio antiquarius.The qPCR results show that the expression level of exsA in different media is different,highest in TSB medium containing bile salts,followed by DMEM medium,and lowest in ordinary TSB medium.[Conclusions]The gene sequence,molecular structure and isoelectric point of exsA,as well as its expression in three different media were obtained.
基金Supported by National Natural Science Foundation of China(3140234431572656)+1 种基金Project of Enhancing School with Innovation of Guangdong Ocean University(GDOU2015050216)Science and Technology Research Program of Guangdong Province(2014A020208117,2015A020209163)
文摘In this paper, the hopPmaJ gene, which encodes type III effector HopPmaJ of Vibrio alginolyticus, was cloned, sequenced and bioinformatically predicted. The results showed that hopPmaJ （GenBank accession number： KX245315） is 345 bp in length and encodes 114 amino acids, with a theoretical molecular mass of 12. 774 kD, and a pI of 4.45. The protein has multiple functional domains and binding sites, but no signal peptide. The tertiary structure of the protein is a homodimer. Based on multiple parameters, the possible dominant B cell antigenic epitopes of HopPmaJ were predicted to be at positions 13 - 16, 29 -30, 40 -42, 45 -49 and 84 -91.
基金supported by grants of the National Key R&D Program of China(Grants 2018YFA0901200)National Natural Science Foundation of China(Grants 31725003,31970114,32100034,and 32100149)+2 种基金Scientific Startup Foundation for Doctors of Northwest A and F University(Z1090122001 and Z1090122002)the China Postdoctoral Science Foundation(Grant 2020 M673501)Young Talent Support Program of Shaanxi Province University(20220206).
文摘The type Ⅵ secretion system(T6SS)is a widespread protein secretion apparatus deployed by many Gram-negative bacterial species to interact with competitor bacteria,host organisms,and the environment.Yersinia pseudotuber-culosis T6SS4 was recently reported to be involved in manganese acquisition;however,the underlying regulatory mechanism still remains unclear.In this study,we discovered that T6SS4 is regulated by ferric uptake regulator(Fur)in response to manganese ions(Mn^(2+)),and this negative regulation of Fur was proceeded by specifically recogniz-ing the promoter region of T6SS4 in Y.pseudotuberculosis.Furthermore,T6SS4 is induced by low Mn^(2+)and oxidative stress conditions via Fur,acting as a Mn^(2+)-responsive transcriptional regulator to maintain intracellular manganese homeostasis,which plays important role in the transport of Mn^(2+)for survival under oxidative stress.Our results pro-vide evidence that T6SS4 can enhance the oxidative stress resistance and virulence for Y.pseudotuberculosis.This study provides new insights into the regulation of T6SS4 via the Mn^(2+)-dependent transcriptional regulator Fur,and expands our knowledge of the regulatory mechanisms and functions of T6SS from Y.pseudotuberculosis.
文摘Objective:To investigate the frequency of exoU and exoY genes in patients with Pseudomonas aeruginosa infection.Methods:In this study,100 clinical isolates of Pseudomonas aeruginosa were collected from patients hospitalized in educational-therapeutic hospitals and were identified using standard microbiological tests.Then,the antibiotic resistance pattern of the isolates was determined by the disk agar diffusion method.The bacterial DNAs were extracted by the alkaline lysis method.Finally,the presence of exoU and exoY genes was evaluated by the PCR test.Results:In this study,47%,72%,29%,39%,40%,and 44%of the isolates were non-susceptible to piperacillin,aztreonam,ceftazidime,imipenem,tobramycin,and ciprofloxacin,respectively.In addition,95%and 93%of the clinical isolates carried the exoU and exoY genes.Blood and fecal isolates had both virulence genes,while only one wound isolate had neither genes.Meanwhile,all urinary isolates contained the exoY gene and only one isolate lacked the exoU gene.Also,88 isolates simultaneously had both exoU and exoY genes.Conclusions:High prevalence of exoU and exoY genes in this region indicates a significant role of typeⅢsecretion system in pathogenesis of Pseudomonas aeruginosa.The typeⅢsecretion system may be a suitable target to reduce the pathogenicity of this bacterium.
文摘Hydrazones of poorly studied fluorine-containing oxamic acid thiohydrazides were synthesized by the reaction with salicylaldehydes. Tests showed that the newly synthesized compounds were effective low-toxic inhibitors of type III secretion system in Chlamydia trachomatis.
基金This work was supported by funds from the National Basic Research Program(973 Program)(Nos.2011CB911104 and 2012CB917202)the National Natural Science Foundation of China(Grant No.31100538)to F.W.,(Grant No.31170817)to C.T.
文摘Mycosin-1 protease(MycP1)is a serine protease anchored to the inner membrane of Mycobacterium tuberculosis,and is essential in virulence factor secretion through the ESX-1 type VII secretion system(T7SS).Bacterial physiology studies demonstrated that MycP1 plays a dual role in the regulation of ESX-1 secretion and virulence,primarily through cleavage of its secretion substrate EspB.MycP1 contains a putative N-terminal inhibitory propeptide and a catalytic triad of Asp-His-Ser,classic hallmarks of a sub-tilase family serine protease.The MycP1 propeptide was previously reported to be initially inactive and activated after prolonged incubation.In this study,we have deter-mined crystal structures of MycP1 with(MycP124-422)and without(MycP1^(63-422))the propeptide,and conducted EspB cleavage assays using the two proteins.Very high struc-tural similarity was observed in the two crystal structures.Interestingly,protease assays demonstrated positive EspB cleavage for both proteins,indicating that the putative propeptide does not inhibit protease activity.Molecu-lar dynamic simulations showed higher rigidity in regions guarding the entrance to the catalytic site in MycP124-422 than in MycP1^(63-422),suggesting that the putative propeptide might contribute to the conformational stability of the active site cleft and surrounding regions.
