Some Environmental Factors Affecting the Length of Escherichia coli Organisms in Continuous Cultures

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Abstract
SUMMARY: The lengths of organisms of Escherichia coli B/r grown in continuous culture in a glucose salts medium were measured over a wide range of population densities at 22° and 37° In some cases the cultures were exposed to continuous gamma radiation at dose rates of 600 r./hr. at 22° and of 1000 r./hr. at 37°. The average length of the forms and the distribution with respect to length depended upon the temperature, population density and radiation dose rate. The growth rate was almost independent of population density over the range in which the average length of organism showed such a marked dependence. No significant differences in growth rate were observed as between unirradiated and irradiated cultures. Changes in average length of organisms are regarded as phenotypic responses to changes in growth conditions, some conditions favouring division and others inhibiting division amongst short organisms.