Effect of hypergravitational stress on microbial cell viability.
Cell of Escherichia coli B, Thiobacillus intermedius 13-1, Bacillus amyloliquefaciens IFO14141, Staphylococcus aureus IID975, and Saccharomyces cerevisiae Kyokai no. 7 cultivated in nutrient media were subjected to hypergravitational stress for a period of between 1 and 24 h at 450,000 x g. The E. coli, B. amyloliquefaciens and S. cerevisiae cells showed survival rates of 38.5%, 0.005%, and 14.7%, respectively, after gravity treatment for 24 h as determined by their ability for colony formation, whereas a survival rate of S. cerevisiae cells of almost 100% was observed as determined using the methylene blue reduction test. E. coli cells, either in the logarithmic growth phase or cultivated in minimum media, were more sensitive to gravitational stress than those either in the stationary phase or cultivated in nutrient media.
Yoshida
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Department of Biological Resource Sciences, Faculty of Agriculture, Miyazaki University, 1-1 Gakuen Kibanadai-Nishi, Miyazaki-shi 889-2192, Japan.
Minamimura
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Yoshida
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Ogawa
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K