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Calcium plays an essential role in a variety of stress responses of eukaryotic cells; however, its function in prokaryotes is obscure. Bacterial ion channels that transport Ca(2+) are barely known. We investigated temperature-induced changes in intracellular concentration of Ca(2+), Na(+) and K(+) in the cyanobacterium Synechocystis sp. strain PCC 6803 and its mutant that is defective in mechanosensitive ion channel MscL. Concentration of cations rapidly and transiently increased in wild-type cells in response to cold and heat treatments. These changes in ionic concentrations correlated with the changes in cytoplasmic volume that transiently decreased in response to temperature treatments. However, no increase in ionic concentrations was observed in the MscL-mutant cells. It implies that MscL functions as a non-specific ion channel, and it participates in regulation of cell volume under temperature-stress conditions.

As a result of screening of spore-forming bacteria, a B-13186 strain with a wide spectrum of antagonistic activity identified as Brevibacillus laterosporus by the analysis of sequences of variable sites of 16S rRNA was selected. Morphological, cultural and biochemical characteristics of the strain were studied. A distinctive feature of the strain is the presence of a canoe-like inclusion formed in sporangia and attached to the mature spore, as well as the ability to synthesize round-shaped crystalline inclusions. The strain was shown to be active against various species of gram-positive bacteria including A search for strains capable of simultaneously producing high amounts of several biologically valuable compounds and/or having high biomass productivity has been carried out. The growth characteristics and biochemical composition of 12 microalgae and cyanobacteria strains from the IPPAS Collection in the exponential and stationary growth phases were studied. All the strains had high growth rates (doubling time 6-22 h). The strains of Cyanobacterium sp. IPPAS B-1200, Chlorella sp. IPPAS C-1210, Nannochloris sp. IPPAS C-1509, Cyanidium caldarium IPPAS P-510 and Vischeria sp. IPPAS H-242 demonstrated the highest biotechnological potential and can be used for the production of various types of biofuel, pigments, feed and food additives, including those with high content of eicosapentaenoic (20:5 Δ5,8,11,14,17) acid content. microalgae, cyanobacteria, biochemical composition, fatty acids, valuable metabolites, growth characteristics This work was supported by a grant from the Russian Science Foundation [no. 14-14-00904]