Growth pattern and adenosine phosphates in psychrotrophic Vibrio spp. at different growth temperatures

Abstract

Growth curves of the psychrotrophic Vibrio isolates showed an increased slope throughout growth (in Type I strains) or a decreased slope after the stationary phase of growth (in Type II strains). Type I and II strains had optimum growth temperatures of 15 to 25°C and 20 to 30°C, respectively. Adenylate levels in Type I strains were markedly high for AMP, moderate for ADP, and low for ATP, and the major part of adenosine phosphates in Type II strains was occupied by AMP during the growth phase with all of them disappearing during the death phase, regardless of the growth temperatures. In Type I strains the concentrations of AMP, ADP, and ATP increased with growth, and in Type II strains the AMP concentration rose quickly, reached a maximum, and fell abruptly to the base during growth, independent of the growth temperatures. The values of energy charge during growth showed as 0.38 or below in both Type strains during growth at optimum temperatures or below. These results differed from those in Escherichia coli. Moreover, it was suggested that the strains of the same Type comprise the same ecological groups. The results indicate that the two Type strains are composed of different ecotypes, and the low energy charge and the dominance of AMP are characteristic of the psychrotrophic Vibrio spp.