title: Transcriptional expression of fljB:z66, a flagellin gene located on a novel linear plasmid of Salmonella enterica serovar Typhi under environmental stresses.
abstract: A previous study identified that z66+ strain of Salmonella enterica serovar Typhi contains two different flagellin genes, the fliC encoding d or j antigen in chromosome and the fljB-like gene encoding z66 antigen in a novel linear plasmid, respectively. The promoter of fljB:z66 is different from that of fliC:d/j and z66+ strain alters flagellin expression in only one orientation, from z66 to d orj antigen, raising the suspicion that z66+ strain is a special biphasic strain. To clarify the expressional characteristics of flagellin genes of z66+ strain, expression patterns of fljB:z66 and fliC were investigated by RT-PCR under a series of environmental stresses during infection, such as acidic stress, osmotic stress, bile acid stress and oxidative stress. Results showed that the expression level of fljB:z66 is over 10-fold higher than the level of fliC in low and middle osmotic conditions before stresses. Only the expressional regulatory tendency of fljB:z66 in response to bile acid stress is similar to that of fliC. Differential expressional patterns between fljB:z66 and fliC of S. enterica serovar Typhi were seen under osmotic stress, bile acid stress and oxidative stress. These results support the hypothesis that the z66+ strain is a special biphasic strain of S. enterica serovar Typhi.
authors.affiliation: Department of Biochemistry and Molecular Biology, Jiangsu University School of Medical Technology, Jiangsu Zhenjiang, China.
authors.forename: Shungao
authors.initials: S
authors.lastname: Xu
authors.forename: Haifan
authors.initials: H
authors.lastname: Zhang
authors.forename: Xiumei
authors.initials: X
authors.lastname: Sheng
authors.forename: Huaxi
authors.initials: H
authors.lastname: Xu
authors.forename: Xinxiang
authors.initials: X
authors.lastname: Huang
mesh_terms: D000942:Antigens, Bacterial / Q000096:biosynthesis* / Q000235:genetics; D001647:Bile Acids and Salts / Q000633:toxicity; D005408:Flagellin / Q000096:biosynthesis* / Q000235:genetics; D020869:Gene Expression Profiling; D009997:Osmotic Pressure; D018384:Oxidative Stress; D010957:Plasmids; D012329:RNA, Bacterial / Q000096:biosynthesis; D012333:RNA, Messenger / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012485:Salmonella typhi / Q000187:drug effects / Q000235:genetics*
chemical_list: D000942:Antigens, Bacterial; D001647:Bile Acids and Salts; C094427:FljB protein, Salmonella; D012329:RNA, Bacterial; D012333:RNA, Messenger; C487817:z66 antigen, Salmonella enterica; D005408:Flagellin