Türk Bilimsel Derlemeler Dergisi

Yazarlar: GÜLBENZER S., ÖKMEN G.

Konular:-

Anahtar Kelimeler:Osmoadaptation,Compatible solute,Microorganism

Özet: Microorganisms respond to osmotic stress mostly by accumulating compatible solutes, either by uptake from the medium or by de novosynthesis. These osmotically active molecules preserve the positive turgor pressure required for cell division. The majority of organisms limitthe cytoplasmic ionic strength to rather low levels, because most intracellular macromolecules are sensitive to high levels of inorganic ions. Twogeneral 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 fewmajor 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 directprotective effects towards critical macromolecules, which explains their function to achieve tolerance towards general stresses such as desiccationand high temperatures. Knowledge regarding microbial salt tolerance is not only useful to characterize strain specific adaptations to ecologicalniches, but it can also be used to generate cells with increased tolerance to adverse environmental conditions for biotechnological purposes. Thisreview provides an overview of osmoadaptation and microorganisms.

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