“Garpun” Defended The Pathogen Of Tularemia From Immunity


Swiss Scientists Described The Molecular Mechanism That Allows Tularemia Causative Agents To Prevent The Immune Response.

“Garpun” Defended The Pathogen Of Tularemia From Immunity
PRINCIPLE OF OPERATION T6SS V. cholerae / © avatar joshi et al., TRENDS IN MICROBIOLOGY, 2016

A distinctive feature of F. Tularensis is the ability to multiply in the cytoplasm of macrophages – cells of the first line of immune protection. After capturing macrophage, the pathogen is placed in the endosome and then – in the digestive vacuol. However, F. Tularensis can return from endosome to cytoplasm. At the same time, the genome of the bacterium contains islands of pathogenicity – characteristic of virulent microorganisms of loci, which are capable of interspecific or horizontal intraspecific transmission. Sequencing of these sites has shown that they are also included coded T6SS, and its composition differs from the previously described. Now scientists clarified the features of the secretion system of type IV F. Tularensis.

According to the results, the release of bacteria from the endosome is mediated by T6SS – this confirmed the deletion of two species-specific genes, as a result of which F. Tularensis has lost opportunities to return to the cytoplasm of macrophage. In addition, the researchers found that the pathogen collects "harpoon" at the ends of a row-shaped cell – it is likely that it allows you to design a set of greater length to increase the volume of delivered toxins. However, protein providing system F. Tularensis energy turned out to be comparable to protein V. Cholerae. Scientists note that, despite the clarification of the T6SS role, the mechanism of dissolution of the immunity cell membrane requires additional study.

The Article IS Published in The Journal Nature Communications.

Earlier, "harpuna" and "machine guns" were found in dinoflagelles.

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