Cyanobacteria Blue-Green Algae and other Photosynthetic Bacteria

6 Cyanobacteria (Blue-Green Algae) and other Photosynthetic Bacteria 

The great interest in PolyP metabolism in Cyanobacteria is connected with the ability of PolyPs to grow rapidly under P, and heavy metal excesses in the water. In many studies, special attention was paid to a possible use of cyanobacteria as assimilators of substantial amounts of phosphate in the form of PolyP. This problem arose from severe pollution of inland waters with various detergents, among which PolyP3 is the most abundant pollutant. 

In Anacystis nidulans, the intacellular PolyP level, which was manipulated by growth in the presence of various P concentrations in the medium (0.3-3 mM), increased with the Pi concentration up to 2.1 mM and decreased thereafter (Keyhani et al., 1996). Thus, the PolyP accumulation in cyanobacteria depended on the phosphorus content in the medium, as in other bacteria. The growth rate of cyanobacteria under phosphate starvation has been shown to be a function of the amount of previously accumulated PolyPs in the cells (Rhee, 1973). PolyP storage is a survival strategy under conditions of fluctuating phosphate supply characteristic of the environmental conditions, in which the cyanobacteria live (Falkner et al, 1995). 

The above studies also give evidence of multiple localization of PolyP in the cells of cyanobacteria. This conclusion was confirmed by a 31P NMR spectroscopic study. In the cyanobacterium Synechocystis sp., two pools of soluble PolyP were identified in vivo by 31P NMR spectroscopy (Lawrence et al, 1998). One of these (PolyP-cation complexes) lost their association cations after EDTA treatment, while the other did not. 

The increase of PolyP accumulation in cyanobacteria was observed under conditions of sulfur deficiency, which diminished the growth (Lawry and Jensen, 1979 1986). This 

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Cyanobacteria (blue-green algae) and other photosynthetic bacteria... 

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