Desialylation by <i>Edwardsiella tarda</i> is the initial step in the regulation of its invasiveness
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- Linh Khanh Vo
- Faculty of Fisheries, Kagoshima University, Kagoshima, Japan
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- Toshiharu Tsuzuki
- Faculty of Fisheries, Kagoshima University, Kagoshima, Japan
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- Yuko Kamada-Futagami
- Faculty of Fisheries, Kagoshima University, Kagoshima, Japan
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- Petros Kingstone Chigwechokha
- The United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima, Japan
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- Akinobu Honda
- The United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima, Japan
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- Kazuki Oishi
- The United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima, Japan
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- Masaharu Komatsu
- Faculty of Fisheries, Kagoshima University, Kagoshima, Japan
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- Kazuhiro Shiozaki
- Faculty of Fisheries, Kagoshima University, Kagoshima, Japan
説明
<jats:title>Abstract</jats:title> <jats:p>Edwardsiella tarda is a gram-negative bacterium causing significant economic losses to aquaculture. E. tarda possesses NanA sialidase which removes sialic acids from α2–3 sialo-glycoprotein of host cells. However, the relationship between NanA sialidase activity and E. tarda invasiveness remains poorly understood. Furthermore, the pathway of sialic acid metabolism in E. tarda remains to be elucidated. We studied sialidase activity in several E. tarda strains and found that the pathogenic strains exhibited higher sialidase activity and greater up-regulation of the NanA mRNA level than non-pathogenic strain. Pathogenic strains also showed higher rates of infection in GAKS cells, and the infection was drastically suppressed by sialidase inhibitor. Additionally, NanA gene overexpression significantly increased infection and treatment of E. tarda with free sialic acid enhanced the rate of infection in GAKS cells. Sialic acid treatment enhanced mRNA levels of two N-acetylneuraminate lyases and one N-acetylneuraminate cytidylyltransferase. E. tarda uses sialic acid as a carbon source for growth via N-acetylneuraminate lyases. The strains with high N-acetylneuraminate cytidylyltransferase level showed greater sialylation of the lipopolysaccharides and glycoproteins. Our study establishes the significance of desialylation by E. tarda sialidase in the regulation of its invasiveness.</jats:p>
収録刊行物
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- Biochemical Journal
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Biochemical Journal 476 (21), 3183-3196, 2019-11-05
Portland Press Ltd.
