Temperature and nutrient availability control growth rate and fatty acid composition of facultatively psychrophilic <Emphasis Type="Italic">Cobetia marina</Emphasis> strain L-2 |
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Authors: | Email author" target="_blank">Isao?YumotoEmail author Kikue?Hirota Hideaki?Iwata Masatoshi?Akutsu Keita?Kusumoto Naoki?Morita Yoshio?Ezura Hidetoshi?Okuyama Hidetoshi?Matsuyama |
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Institution: | (1) Research Institute of Biological Resources, National Institute of Advanced Industrial Science and Technology, 2-17-2-1 Tsukisamu-Higashi, Toyohira-ku, Sapporo, 062-8517, Japan;(2) Department of Bioscience and Technology School of Engineering, Hokkaido Tokai University, Sapporo, 005-8601, Japan;(3) Department of Fisheries, Oceanography & Marine Science, Faculty of Fisheries, Hokkaido University, Hakodate, 041-0821, Japan;(4) Laboratory of Environmental Molecular Biology, Graduate School of Environmental Earth Science, Hokkaido University, Sapporo, 060-0810, Japan |
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Abstract: | A facultative psychrophilic bacterium, strain L-2, that grows at 0 and 5°C as minimum growth temperatures in complex and defined media, respectively, was isolated. On the basis of taxonomic studies, strain L-2 was identified as Cobetia marina. The adaptability of strain L-2 to cold temperature was higher than that of the type strain and of other reported strains of the same species. When the bacterium was grown at 5–15°C in a defined medium, it produced a high amount of trans-unsaturated fatty acids. By contrast, in a complex medium in the same temperature range it produced a low amount of trans-unsaturated fatty acids. In the complex medium at 5°C, the bacterium exhibited a three-fold higher growth rate than that obtained in the defined medium. Following a temperature shift from 11 to 5°C, strain L-2 grew better in complex than in defined medium. Furthermore, when the growth temperature was shifted from 0 to 5°C both the growth rate and the yield of strain L-2 growing in complex medium was markedly enhanced. These phenomena suggest that an upshift of the growth temperature had a positive effect on metabolism. The effects of adding complex medium components to the defined medium on bacterial growth rate and fatty acid composition at 5°C were also studied. The addition of yeast extract followed by peptone was effective in promoting rapid growth, while glutamate addition was less effective, resulting in a cis-unsaturated fatty acid ratio similar to that of cells grown in the complex medium. These results suggest that the rapid growth of strain L-2 at low temperatures requires a high content of various amino acids rather than the presence of a high ratio of cis-unsaturated fatty acids in the cell membrane. |
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Keywords: | Facultative psychrophile Cobetia marina cis-Unsaturated fatty acid trans-Unsaturated fatty acid Cold adaptation |
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