Objective Campylobacter jejuni NCTC11168 is commonly used as a standard strain for flagellar biosynthesis research.In this report,two distinguished phenotypic isolates(CJ1Z,flhA mutant strain,lawn;CJ2S,flhA complement...Objective Campylobacter jejuni NCTC11168 is commonly used as a standard strain for flagellar biosynthesis research.In this report,two distinguished phenotypic isolates(CJ1Z,flhA mutant strain,lawn;CJ2S,flhA complemented strain,normal colony)appeared during laboratory passages for NCTC11168.Methods Phenotypic assessments,including motility plates,transmission electron microscopy,biofilm formation assay,autoagglutination assay,and genome re-sequencing for these two isolates(CJ1Z,flhA mutant strain;CJ2S,flhA complemented strain)were carried out in this study.Results Transmission electron microscopy revealed that the flagellum was lost in CJ1Z.Phenotypic assessments and genome sequencing of the two isolates were performed in this study.The capacity for biofilm formation,colony auto-agglutination,and isolate motility was reduced in the mutant CJ1Z.Comparative genomic analysis indicated a unique native nucleotide insertion in flhA(nt,2154)that caused the I719Y and I720Y mutations and early truncation in flhA.Conclusion FlhA has been found to influence the expression of flagella in C.jejuni.To the best of our knowledge,this is the first study to describe the function of the C-terminal of this protein.展开更多
To determine the pathogenic potential of the leptospiral flagella-associated proteins, the genes flhA and flhB2 encoding the biosynthesis of flagella of leptospira interrogans serogroup icterohaemor- rhagiae serovar l...To determine the pathogenic potential of the leptospiral flagella-associated proteins, the genes flhA and flhB2 encoding the biosynthesis of flagella of leptospira interrogans serogroup icterohaemor- rhagiae serovar lai stain 56601 were cloned and their prokaryotic expression systems were constructed. It was demonstrated that the cloned flhA and flhB2 genes had 2118 bp in length and showed 100% and 99.9% of homologies in their nucleotide sequences and 100% and 98.8% of homologies in their putative amino acid sequences respectively, in comparison with those of previously reported. The prokaryotic expression systems under the induction with IPTG could efficiently express the target proteins rFlhA and rFlhB2 with the outputs of approximate 10% of the total bacterial proteins. Based on the sequences of the cloned genes flhA and flhB2, the structural features in associated with pathogenesis and the functions of the target proteins were analyzed with bioinformatics softwares, in which the FlhA was found to have 7 major transmembrane helices, while the FlhB2 had 5 ones. The conserved domains in the FlhA showed high similarity to those of the FHIPEP of the other bacterial FlhA and EscV families, but the conserved domains in the FlhB2 were similar to those of bac-export-2 and EscU families, EscV and EscU families being the protein products of the type IR secretion system in association with pathogenesis. The FlhA and FlhB2 also contained protein kinase C （PKC） and protein tyrosine kinase （PTK） phosphorylation sites, indicating that PKC and PTK of host cells were involved in the internalization and intracellular proliferation in the pathogenesis of microorganisms. All these data leads to a conclusion that the flhA and flhB2 genes of L. interrogans are relatively conserved and their gene products have great potential in the pathogenesis of this organism.展开更多
基金supported by the National Key Research and Development Program of China[2021YFC2301000]the Project for Novel Detection Techniques of Bacterial Pathogens[32073]+1 种基金Enhancement of Comprehensive Monitoring,Prevention,and Control Capabilities for Traditional Infectious Diseases Such as Plague,Cholera,and Brucellosis[102393230020020000002]Prevention and Intervention of Bacterial and Fungal Infectious Diseases[102393220020020000031]。
文摘Objective Campylobacter jejuni NCTC11168 is commonly used as a standard strain for flagellar biosynthesis research.In this report,two distinguished phenotypic isolates(CJ1Z,flhA mutant strain,lawn;CJ2S,flhA complemented strain,normal colony)appeared during laboratory passages for NCTC11168.Methods Phenotypic assessments,including motility plates,transmission electron microscopy,biofilm formation assay,autoagglutination assay,and genome re-sequencing for these two isolates(CJ1Z,flhA mutant strain;CJ2S,flhA complemented strain)were carried out in this study.Results Transmission electron microscopy revealed that the flagellum was lost in CJ1Z.Phenotypic assessments and genome sequencing of the two isolates were performed in this study.The capacity for biofilm formation,colony auto-agglutination,and isolate motility was reduced in the mutant CJ1Z.Comparative genomic analysis indicated a unique native nucleotide insertion in flhA(nt,2154)that caused the I719Y and I720Y mutations and early truncation in flhA.Conclusion FlhA has been found to influence the expression of flagella in C.jejuni.To the best of our knowledge,this is the first study to describe the function of the C-terminal of this protein.
文摘To determine the pathogenic potential of the leptospiral flagella-associated proteins, the genes flhA and flhB2 encoding the biosynthesis of flagella of leptospira interrogans serogroup icterohaemor- rhagiae serovar lai stain 56601 were cloned and their prokaryotic expression systems were constructed. It was demonstrated that the cloned flhA and flhB2 genes had 2118 bp in length and showed 100% and 99.9% of homologies in their nucleotide sequences and 100% and 98.8% of homologies in their putative amino acid sequences respectively, in comparison with those of previously reported. The prokaryotic expression systems under the induction with IPTG could efficiently express the target proteins rFlhA and rFlhB2 with the outputs of approximate 10% of the total bacterial proteins. Based on the sequences of the cloned genes flhA and flhB2, the structural features in associated with pathogenesis and the functions of the target proteins were analyzed with bioinformatics softwares, in which the FlhA was found to have 7 major transmembrane helices, while the FlhB2 had 5 ones. The conserved domains in the FlhA showed high similarity to those of the FHIPEP of the other bacterial FlhA and EscV families, but the conserved domains in the FlhB2 were similar to those of bac-export-2 and EscU families, EscV and EscU families being the protein products of the type IR secretion system in association with pathogenesis. The FlhA and FlhB2 also contained protein kinase C （PKC） and protein tyrosine kinase （PTK） phosphorylation sites, indicating that PKC and PTK of host cells were involved in the internalization and intracellular proliferation in the pathogenesis of microorganisms. All these data leads to a conclusion that the flhA and flhB2 genes of L. interrogans are relatively conserved and their gene products have great potential in the pathogenesis of this organism.
