Low-molecular-weight carbohydrate biosynthesis and the distribution of cyanobacteria (blue-green algae) in marine environments

Rates of accumulation of low-molecular-weight carbohydrates have been measured for a range of cyanobacteria subjected to hyperosmotic stress (upshock). Synthesis of the disaccharides sucrose and trehalose was more rapid than that of the heteroside glucosyl-glycerol in all strains. The rates of synthesis of organic solutes may affect the distribution of cyanobacteria in natural saline waters:strains that produce either sucrose or trehalose in response to increased external salinity are often found in brackish habitats where the salinity regime is unstable and rapid organic solute synthesis may be advantageous. In contrast, cyanobacteria that synthesize glucosyl-glycerol are more commonly isolated from environments of less variable salinity.