Cold resistant mutants of Escherichia coli.

Kawamoto, Shinichi; Kojima, Kana; Hanada, Toshiyuki; Tokuyama, Shogo; Yashima, Shigetaka; Eguchi, Yoshitomo

doi:10.1271/bbb1961.48.1097

Cited by 4 publications

(1 citation statement)

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“…Mutations in a single critical gene (e.g., in temperature-sensitive mutants) can lower the maximum temperature of growth, but the factor(s) determining the whole limit of growth is not known. A few studies have been carried out in this direction [7,12,14,20], but none of them have been followed up with definitive conclusions.…”

Section: Discussionmentioning

confidence: 99%

Transcriptional Activity at Supraoptimal Temperature of Growth in the Antarctic Psychrotrophic Bacterium Pseudomonas syringae

et al. 1999

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Transcriptional activity was monitored in cells of the Antarctic psychrotrophic bacterium Pseudomonas syringae (Lz4W), which does not grow above 30 degrees C. It was observed that the bacterium was capable of synthesising RNA at a temperature range of 0-37 degrees C, both in vitro and in vivo. The net incorporation of the radioactive precursor, [3H]uridine, into RNA was found to be affected at 37 degrees C. A pulse-chase experiment following a 32P labeling of RNA in vivo indicated that the ribosomal RNAs (rRNAs) degrade faster at and above 30 degrees C. It was also found that the increased ribonuclease (RNase) activity at high temperature might be responsible for this degradation. The attack on ribosomal RNAs by RNase took place after their assembly into ribosomal particles. It is suggested that the degradation of rRNAs at supraoptimal temperatures might be a detrimental factor for growth above 30 degrees C.

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Section: Discussionmentioning

confidence: 99%

Transcriptional Activity at Supraoptimal Temperature of Growth in the Antarctic Psychrotrophic Bacterium Pseudomonas syringae

et al. 1999

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Psychrophilic and psychrotrophic microorganisms

Gounot

1986

Experientia

134

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Psychrophilic and psychrotrophic microorganisms have the ability to grow at 0 degree C. Psychrotrophic microorganisms have a maximum temperature for growth above 20 degrees C and are widespread in natural environments and in foods. Psychrophilic microorganisms have a maximum temperature for growth at 20 degrees C or below and are restricted to permanently cold habitats. This ability to grow at low temperature may be correlated with a lower temperature characteristic than that of the mesophiles, an increasing proportion of unsaturated fatty acids in the lipid phase of the cell membrane, which makes it more fluid, and a protein conformation functional at low temperature. The relatively low maximum temperature of growth for these microorganisms is often considered to be due to the thermolability of one or more essential cellular components, particularly enzymes, while some degradative activities are enhanced, resulting in an exhaustion of cell energy, a leakage of intracellular substances or complete lysis. Psychrotrophic microorganisms are well-known for their degradative activities in foods. Some are pathogenic or toxinogenic for man, animals or plants. However in natural microbial ecosystems psychrotrophic and psychrophilic microorganisms can play a large role in the biodegradation of organic matter during cold seasons.

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