Objective To determine the distribution of two important virulence factors[lipooligosaccharide(LOS)and capsular polysaccharide(CPS)]in Campylobacter jejuni(C.jejuni)isolated from different sources in China and to deve...Objective To determine the distribution of two important virulence factors[lipooligosaccharide(LOS)and capsular polysaccharide(CPS)]in Campylobacter jejuni(C.jejuni)isolated from different sources in China and to develop a rapid screening method for Guillain–Barrésyndrome(GBS)-associated strains.Methods Whole-genome sequencing was carried out for 494 C.jejuni strains.The Ortho MCL software was used to define the LOS/CPS gene clusters.CPS genotyping was performed with serotype-specific sequence alignment using the BLAST software.Real-time Polymerase chain reaction(PCR)was developed with the unique sequences of specific CPS types.Results Nine novel and 29 previously confirmed LOS classes were identified.LOS classes A,B,and C were the most common(48.2%,238/494)among the 494 strains.Twenty-six capsular types were identified in 448 strains.HS2,HS4c,HS5/31,HS19,and HS8/17 were the most frequent CPS genotypes(58.7%,263/448).Strains of 17 CPS genotypes(strain number>5)had one or two prevalent LOS classes(P<0.05).Multiplex real-time PCR for rapid identification of HS2,HS19,and HS41 was developed and validated with strains of known serotypes.Conclusion Our results describe the genetic characteristics of the important virulence factors in C.jejuni strains in China.The multiplex real-time PCR developed in this study will facilitate enhanced surveillance of GBS-associated strains in China.展开更多
Extractable glycolipids of mycobacteria,such as lipooligosaccharides(LOSs),play crucial roles in responding to environmental stress and modulating the host immune response.Although the biosynthesis of LOS is likely re...Extractable glycolipids of mycobacteria,such as lipooligosaccharides(LOSs),play crucial roles in responding to environmental stress and modulating the host immune response.Although the biosynthesis of LOS is likely regulated at multiple levels to ensure proper composition of the cell wall,the key regulators remain unknown.In this study,we investigated B11,a conserved mycobacterial small RNA(sRNA),and found that it post-transcriptionally regulates LOS synthesis in Mycobacterium marinum.Through a combination of RNA-seq and mass spectrometry screening,we identified specific genes within the LOS synthesis locus that are directly regulated by B11.We confirmed in vivo sRNA-mRNA interactions using MS2-tagged RNA affinity purification,and found that B11 utilizes the cytosine-rich loop of its Rho-independent transcriptional terminator to interact with guanine tracks adjacent to the ribosome binding sites of its target genes,thereby impeding translation and promoting mRNA degradation.Moreover,deletion of B11 altered the colony morphology associated with LOS composition.These comprehensive functional studies of the mycobacterial sRNA B11 reveal sRNA-based regulation of LOS synthesis,providing new insights into the regulatory mechanisms controlling the biosynthesis of the complex mycobacterial cell wall.展开更多
基金supported by the National Key Research and Development Program of China[2021YFC2301000]the Sanming Project of Medicine in Shenzhen[SZSM201803081]。
文摘Objective To determine the distribution of two important virulence factors[lipooligosaccharide(LOS)and capsular polysaccharide(CPS)]in Campylobacter jejuni(C.jejuni)isolated from different sources in China and to develop a rapid screening method for Guillain–Barrésyndrome(GBS)-associated strains.Methods Whole-genome sequencing was carried out for 494 C.jejuni strains.The Ortho MCL software was used to define the LOS/CPS gene clusters.CPS genotyping was performed with serotype-specific sequence alignment using the BLAST software.Real-time Polymerase chain reaction(PCR)was developed with the unique sequences of specific CPS types.Results Nine novel and 29 previously confirmed LOS classes were identified.LOS classes A,B,and C were the most common(48.2%,238/494)among the 494 strains.Twenty-six capsular types were identified in 448 strains.HS2,HS4c,HS5/31,HS19,and HS8/17 were the most frequent CPS genotypes(58.7%,263/448).Strains of 17 CPS genotypes(strain number>5)had one or two prevalent LOS classes(P<0.05).Multiplex real-time PCR for rapid identification of HS2,HS19,and HS41 was developed and validated with strains of known serotypes.Conclusion Our results describe the genetic characteristics of the important virulence factors in C.jejuni strains in China.The multiplex real-time PCR developed in this study will facilitate enhanced surveillance of GBS-associated strains in China.
基金supported by the Natural Science Foundation of China(81991532 and 32170179 to C.W.and 82272376 to Q.G.)National Key R&D Program of China(2022YFE0111800 to C.W.)the Shanghai Municipal Science and Technology Major Project(ZD2021CY001).
文摘Extractable glycolipids of mycobacteria,such as lipooligosaccharides(LOSs),play crucial roles in responding to environmental stress and modulating the host immune response.Although the biosynthesis of LOS is likely regulated at multiple levels to ensure proper composition of the cell wall,the key regulators remain unknown.In this study,we investigated B11,a conserved mycobacterial small RNA(sRNA),and found that it post-transcriptionally regulates LOS synthesis in Mycobacterium marinum.Through a combination of RNA-seq and mass spectrometry screening,we identified specific genes within the LOS synthesis locus that are directly regulated by B11.We confirmed in vivo sRNA-mRNA interactions using MS2-tagged RNA affinity purification,and found that B11 utilizes the cytosine-rich loop of its Rho-independent transcriptional terminator to interact with guanine tracks adjacent to the ribosome binding sites of its target genes,thereby impeding translation and promoting mRNA degradation.Moreover,deletion of B11 altered the colony morphology associated with LOS composition.These comprehensive functional studies of the mycobacterial sRNA B11 reveal sRNA-based regulation of LOS synthesis,providing new insights into the regulatory mechanisms controlling the biosynthesis of the complex mycobacterial cell wall.
