Deletion of the Riemerella anatipestifer type IX secretion system gene sprA results in differential expression of outer membrane proteins and virulence.

In this study, a sprA deletion mutant was constructed encoding a core protein of T9SS to investigate its influence on outer membrane protein expression and role in virulence. Compared with the wild-type RA-YM strain, the deletion mutant ΔsprA failed to digest gelatin, showed the same growth rate in the logarithmic phase and exhibited greater sensitivity to the bactericidal activity of duck sera, whereas the complemented strain restored these phenotypes. The outer membrane proteome of RA-YM and the ΔsprA mutant were analyzed by Tandem Mass Tags, which revealed 198 proteins with predicted localization to the cell envelope. Sixty-three of these proteins were differentially expressed in the outer membrane, with 43 up-regulated and 20 down-regulated. Among the twelve outer membrane protein which secreted by T9SS, 4 proteins were up-regulated and 1 protein was down-regulated. Animal experiments demonstrated that, the median lethal dose of the mutant strain ΔsprA was about 500 times higher than that of the wild-type RA-YM strain, and bacterial loads in blood, brain, heart, liver and spleen of the ΔsprA-infected ducks were significantly reduced. Our results indicate that the SprA is a virulence-associated factor of RA, and its absence results in altered abundance of outer membrane proteins and secretion disorders associated with some of the T9SS effector proteins. PMID: 30640518 [PubMed - as supplied by publisher]
Source: Avian Pathology - Category: Pathology Authors: Tags: Avian Pathol Source Type: research

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K. E. Lafond et al.
Source: Emerging Infectious Diseases Journal - Category: Infectious Diseases Source Type: research
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Source: Avian Pathology - Category: Pathology Authors: Tags: Avian Pathol Source Type: research
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Source: High Altitude Medicine and Biology - Category: Sports Medicine Authors: Source Type: research
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Source: Veterinary Microbiology - Category: Veterinary Research Source Type: research
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Source: Proceedings of the National Academy of Sciences - Category: Science Tags: In This Issue This Week in PNAS Source Type: research
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Source: Microbial Ecology - Category: Microbiology Authors: Tags: Microb Ecol Source Type: research
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