Microbial water stress.

INTRODUCTION.............................................................. 803 PHYSICOCHEMICAL PARAMETERS .............. ........................... 804 SOME ECOLOGICAL ASPECTS OF MICROBIAL WATER RELATIONS ..... ... 807 Microbial Water Relations and Food .............. ............................ 807 The Saline Environment ..................................................... 807 The Nonionic Environment ......... .......... 809 HYPOTHETICAL EXPLANATIONS OF THE TOLERANCE OF LOW WATER ACTIVITY ..................... 809 HALOPHILIC BACTERIA..................... 811 Cell Envelope and Lipid Biochemistry ........................................ 811 Nutrition..................................................................... 813 Miscellaneous Characteristics .......................................... 813 Gas vacuoles .......................................... 813 "Satellite" DNA .......... ................................ 813 Halophil bacteriophages .................. ........................ 813 Light Reactions of the Red Halophils ......................................... 814 Halophilic Characteristics .................. ........................ 815 Intracellular Physiology ................ .......................... 818 XEROTOLERANT YEASTS .................. ........................ 821 General Biology .......................................... 821 Physiology.................................................................. 822 HALOPHILIC ALGAE ............ .............................. 825 Intracellular Composition .................. ........................ 826 Physiological Role of Glycerol........................................... 827 Regulation of Glycerol Production .......................................... 828 Physiological Basis of Algal Halophilism...................................... 828 Algae Other than D nalie .......................................... 829 COMPATIBLE SOLUTES .............. ........................... 829 Electrolytes................................................................. 829 Nonelectrolytes.............................................................. 833 Physicochemical Mechanism of Nonelectrolyte Action ......... ................ 835 Regulation of Compatible Solute Accumulation ................................ 837 LOOSE ENDS 838 Survival..................................................................... 840 SUMMARY ............... 841 LITERATURE CITED................ 841