Ozmotik Koruyucular ve Mikroorganizmalar

Abstract

Microorganisms respond to osmotic stress mostly by accumulating compatible solutes, either by uptake from the medium or by de novo
synthesis. These osmotically active molecules preserve the positive turgor pressure required for cell division. The majority of organisms limit
the cytoplasmic ionic strength to rather low levels, because most intracellular macromolecules are sensitive to high levels of inorganic ions. Two
general strategies exist for the growth and survival of prokaryotes in environments of elevated osmolarity. Among microorganisms, sucrose,
trehalose, glucosylglycerol and glycine betaine are used as major compatible solutes. The diversity of compatible solutes is large but falls into a few
major chemical categories; they are usually small organic molecules such as amino acids or their derivatives, and carbohydrates or their derivatives.
Some are widely distributed in nature while others seem to be exclusively present in specific groups of organisms. Compatible solutes display direct
protective effects towards critical macromolecules, which explains their function to achieve tolerance towards general stresses such as desiccation
and high temperatures. Knowledge regarding microbial salt tolerance is not only useful to characterize strain specific adaptations to ecological
niches, but it can also be used to generate cells with increased tolerance to adverse environmental conditions for biotechnological purposes. This
review provides an overview of osmoadaptation and microorganisms.