Chemotactic Behavior of Pathogenic and Nonpathogenic Leptospira Species

Institut Pasteur, Unité de Biologie des Spirochètes, Paris, France.
Applied and Environmental Microbiology (Impact Factor: 3.95). 12/2012; 78(23). DOI: 10.1128/AEM.02288-12

ABSTRACT We have developed a capillary tube assay in combination with real-time PCR to quantitate the number of chemoattracted Leptospira cells. We identified Tween 80, glucose, sucrose, and pyruvate as attractants for Leptospira cells; amino acids and vitamin B12 were found to be nonchemotactic or weakly chemotactic. This assay has the general applicability to further our understanding of leptospiral chemotaxis.

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    ABSTRACT: Chemotaxis allows bacterial cells to migrate towards or away from chemical compounds. In the present study, we developed a microscopic agar-drop assay (MAA) to investigate the chemotactic behaviour of a coiled spirochete, Lepto-spira biflexa. An agar drop containing a putative attractant or repellent was placed around the centre of a flow chamber and the behaviour of free-swim-ming cells was analysed under a microscope. MAA showed that L. biflexa cells gradually accumulated around an agar drop that contained an attractant such as glucose. Leptospira cells often spin without migration by transformation of their cell body. The frequency at which cells showed no net displacement decreased with a higher glucose concentration, suggesting that sensing an attractive chemical allows these cells to swim more smoothly. Investigation of the chemotactic behaviour of these cells in response to different types of sugars showed that fructose and mannitol induced negative chemotactic responses, whereas xylose and lactose were non-chemotactic for L. biflexa. The MAA developed in this study can be used to investigate other chemoattractants and repellents.
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