Interrelation between halo- and thermotolerance in anoxygenic phototrophic bacteria

Cultivation of purple and green halophilic phototrophic bacteria at increased concentrations of NaCl resulted in the acquisition of thermotolerance, greater optimal growth temperatures, and inhibition of growth at low temperatures. Similarly, incubation at increased temperatures was found to promote halophily in the bacteria studied. However, there was no change in the temperature characteristics of the organisms when organic osmolytics, glycerol or polyethylene glycol-200, were used instead of NaCl. The revealed interdependence of the relations of the species studied to temperature and salinity could not be explained solely by changes in water activity in the medium.