RELEASE OF ULTRAVIOLET-ABSORBING MATERIAL FROM ESCHERICHIA COLI AT SUBZERO TEMPERATURES

Abstract

When cells of Escherichia coli were suspended in dilute artificial seawater and cooled to various subzero temperatures, a maximum lethal effect occurred around −40 °C. In addition, rapid cooling to −26 °C of bacteria, suspended in concentrated, non-freezing seawater caused a pronounced decrease in viability ("cold shock"). The loss in viability was accompanied by a proportional release from the cells of ultraviolet-absorbing material and by an increase in the ribose and organic phosphorus contents of the suspending liquid. It seems possible that the released material, at least partly, consisted of nucleotides or nucleic acids.