Compatible solutes of organisms that live in hot saline environments

摘要

The accumulation of organic solutes is a prerequisite for osmotic adjustment of all microorganisms. Thermophilic and hyperthermophilic organisms generally accumulate very unusual compatible solutes namely, di-myo-inositol-phosphate, di-mannosyl-di-myoinositol-phosphate, di-glycerol-phosphate, mannosylglycertate and mannosylglyceramide, which have not been idetnfified in bacteria or archaea that grow at low and moderate temperatures. There is also a growing awareness that some of these compatible solutes may have a role in the protection of cell components against thermal denaturation. Mannosylglycerate and di-glycerol-phosphate have been shown to protect enzymes and proteins from thermal denaturation in vitro as well, or better, than compatible solutes from mesophiles. The pathways leading to the synthesis of some of these compatible solutes from thermophiles and hyperthermophiles have been elucidated. However, large numbers of questions remain unanswered. Fundamental and applied interest in compatible soluts and osmotic adjustment in these organisms, drives research that, will, in the near future, allow us to understand the role of compatible solutes in osmotic protection and thermoprotection of some of the most fascinating organisms known on Earth.