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Vibrio vulnificus RtxA1 Toxin Expression Upon Contact With Host Cells Is RpoS-Dependent
The expression of virulence genes in bacteria is known to be regulated by various environmental and host factors. , an estuarine bacterium, experiences a dramatic environmental change during its infection process. We reported that RtxA1 toxin caused acute cell death only when close contact to host c...
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Published in: | Frontiers in cellular and infection microbiology 2018-03, Vol.8, p.70-70 |
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Main Authors: | , , , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | The expression of virulence genes in bacteria is known to be regulated by various environmental and host factors.
, an estuarine bacterium, experiences a dramatic environmental change during its infection process. We reported that
RtxA1 toxin caused acute cell death only when close contact to host cells was allowed. A sigma factor RpoS is a very important regulator for the maximal survival of pathogens under stress conditions. Here, we studied the role of RpoS in
cytotoxicity and mouse lethality. The growth of
mutant strain was comparable to that of wild-type in heart infusion (HI) media and DMEM with HeLa cell lysate. An
mutation resulted in decreased cytotoxicity, which was restored by
complementation. Interestingly, host contact increased the expression and secretion of
RtxA1 toxin, which was decreased and delayed by the
mutation. Transcription of the cytotoxic gene
and its transporter
was significantly increased after host factor contact, whereas the activity was decreased by the
mutation. In contrast, the
mutation showed no effect on the transcriptional activity of a cytolytic heamolysin gene (
). Additionally, the LD
of the
mutant was 15-fold higher than that of the wild-type in specific pathogen-free CD-1 female mice. Taken together, these results show that RpoS regulates the expression of
RtxA1 toxin and its transporter upon host contact. |
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ISSN: | 2235-2988 2235-2988 |
DOI: | 10.3389/fcimb.2018.00070 |