Inactivation of the fliY gene encoding a flagellar motor switch protein attenuates mobility and virulence of Leptospira interrogansstrain LaiReport as inadecuate




Inactivation of the fliY gene encoding a flagellar motor switch protein attenuates mobility and virulence of Leptospira interrogansstrain Lai - Download this document for free, or read online. Document in PDF available to download.

BMC Microbiology

, 9:253

First Online: 09 December 2009Received: 29 March 2009Accepted: 09 December 2009

Abstract

BackgroundPathogenic Leptospira species cause leptospirosis, a zoonotic disease of global importance. The spirochete displays active rotative mobility which may contribute to invasion and diffusion of the pathogen in hosts. FliY is a flagellar motor switch protein that controls flagellar motor direction in other microbes, but its role in Leptospira, and paricularly in pathogenicity remains unknown.

ResultsA suicide plasmid for the fliY gene of Leptospira interrogans serogroup Icterohaemorrhagiae serovar Lai strain Lai that was disrupted by inserting the ampicillin resistance gene bla was constructed, and the inactivation of fliY gene in a mutant fliY was confirmed by PCR and Western Blot analysis. The inactivation resulted in the mRNA absence of fliP and fliQ genes which are located downstream of the fliY gene in the same operon. The mutant displayed visibly weakened rotative motion in liquid medium and its migration on semisolid medium was also markedly attenuated compared to the wild-type strain. Compared to the wild-type strain, the mutant showed much lower levels of adhesion to murine macrophages and apoptosis-inducing ability, and its lethality to guinea pigs was also significantly decreased.

ConclusionInactivation of fliY, by the method used in this paper, clearly had polar effects on downstream genes. The phentotypes observed, including lower pathogenicity, could be a consequence of fliY inactivation, but also a consequence of the polar effects.

Electronic supplementary materialThe online version of this article doi:10.1186-1471-2180-9-253 contains supplementary material, which is available to authorized users.

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Author: Sumei Liao - Aihua Sun - David M Ojcius - Senlin Wu - Jinfang Zhao - Jie Yan

Source: https://link.springer.com/article/10.1186/1471-2180-9-253



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