H₂O₂ tolerance of Vibrio rumoiensis S-1T is attributable to the cellular catalase activity
2008
Ichise, Nobutoshi | Hirota, Kikue | Ichihashi, Daisen | Nodasaka, Yoshinobu | Morita, Naoki | Okuyama, Hidetoshi | Yumoto, Isao
The extraordinarily high level of H₂O₂ tolerance of Vibrio rumoiensis strain S-1T when compared with the tolerance levels of strain S-4, a probable catalase-deficient derivative of strain S-1T, was demonstrated by the introduction of 0-100 mM H₂O₂ during the mid-exponential growth phase. The contribution of catalase to the H₂O₂ tolerance was also demonstrated by comparing the catalase-deficient mutant Escherichia coli strain UM2 with a UM2 strain, harboring the plasmid pBSsa1, which carried the strain S-1T catalase gene vktA. The decomposition rates of 23-25 mM H₂O₂ that was introduced in the culture fluids of strain S-1T and E. coli UM2 harboring pBSsa1 corresponded to the calatase activities of the cells by spectrophotometric measurements. The presence of cell surface catalase was observed by immunoelectron microscopy, using an antibody for intracellular catalase in strain S-1T. The high level of H₂O₂ tolerance of strain S-1T was attributable to the catalase activity of the cells. Cell surface catalase is considered to contribute to the catalase activity of strain S-1T cells.
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