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Regulation of the Yersinia enterocolitica enterotoxin Yst gene : influence of growth phase, temperature, osmolarity, pH and bacterial host factors

Mikulskis, A. V. and Delor, I. and Thi, V. H. and Cornelis, G. R.. (1994) Regulation of the Yersinia enterocolitica enterotoxin Yst gene : influence of growth phase, temperature, osmolarity, pH and bacterial host factors. Molecular microbiology, Vol. 14, H. 5. pp. 905-915.

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Official URL: http://edoc.unibas.ch/dok/A5259227

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Abstract

The chromosome of Yersinia enterocolitica encodes an enterotoxin called Yst. We analysed transcription of chromosomal yst'--luxAB and plasmid-borne yst'--lacZ operon fusions and we observed that regulation of yst expression occurs at transcriptional level. In a wild-type strain, yst was transcribed from at least two major promoters. yst transcription reached a maximum at the entry to the stationary phase and significantly varied in different Y. enterocolitica strains. In some strains, it gradually decreased during the course of our work, suggesting the existence of a mechanism switching the expression of yst to a silent state. Changes in the status of bacterial host factors rather than modifications in the yst gene are responsible for this silencing. Negative regulator YmoA participates in yst silencing and temperature regulation of yst. YmoA was also required for proper growth-phase regulation of yst, although it is not the only factor involved in this regulation. Physico-chemical parameters of the environment play an important role in yst transcription. In usual culture media (e.g. tryptic soy broth), the enterotoxin gene was transcribed only at temperatures below 30 degrees C, which argued against the role of Yst in a prolonged diarrhoea at body temperatures. However, yst transcription could be induced at 37 degrees C by increasing osmolarity and pH to the values normally present in the ileum lumen. This finding reconciles the observations concerning yst expression in a host environment and in bacterial cultures, thus supporting the idea that enterotoxin Yst is a virulence factor of Y. enterocolitica.
Faculties and Departments:05 Faculty of Science > Departement Biozentrum > Former Organization Units Biozentrum > Molecular Microbiology (Cornelis)
UniBasel Contributors:Cornelis, Guy R.
Item Type:Article, refereed
Article Subtype:Research Article
Bibsysno:Link to catalogue
Publisher:Blackwell
ISSN:0950-382X
Note:Publication type according to Uni Basel Research Database: Journal article
Last Modified:22 Mar 2012 14:20
Deposited On:22 Mar 2012 13:22

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