[Expression of drgA gene encoding NAD(P)H:quinone-oxidoreductase in cells of the cyanobacterium Synechocystis sp. PCC 6803].

The gene drgA of the cyanobacterium Synechocystis sp. PCC 6803 encoding soluble NAD(P)H:quinone-oxidoreductase is involved in NADPH oxidation and controls cell sensitivity to nitroaromatic inhibitors as well as resistance to the oxidative stress inducer menadione. The expression of drgA was analyzed by means of Northern blot hybridization and RT-PCR technique.

[Genetic control and mechanisms of salt and hyperosmotic shock resistance in cyanobacteria].

Exposure to high concentrations of environmental NaCl exerts two stress effects on living cells, increasing the osmotic pressure and the concentration of inorganic ions. Salt stress dramatically suppresses the photosynthetic activity in cells of phototrophic organisms, such as cyanobacteria. During salt adaptation, cyanobacterial cells accumulate osmoprotectors, export excessive Na+ with the help of Na+/H+ antiporters, and actively absorb K+ with the help of K+-transporting systems.

[Cloning and identification of an Agrobacterium radiobacter 5D-1 chromosome fragment involved in control of nitrogen metabolism, biosynthesis of indolylacetic acid and replication of ColE1 plasmids].

Pleiotropic chromosomal mutations were earlier identified in saprophytic associative bacterium Agrobacterium radiobacter 5D-1. The mutations changed nitrogen metabolism, disturbed synthesis of indolylacetic acid (IAA), and conferred the ability to sustain replication of ColE1 plasmid derivatives, which are not normally maintained in bacteria other than Escherichia. The mutations were designated Nr (Nitrogen metabolism) and assigned to a single cluster on an A.

[Mossbauer spectroscopy of cells of cyanobacteria Synechocystis sp. PCC 6803 devoid of photosystem I and containing inactive phycobilisomes].

Mossbauer spectra of the psaAB mutant of Synechocystis sp. PPC 6803 devoid of photosystem I grown in a 57Fe-containing medium were measured. The spectrum is a broadened doublet whose size (about 20%) and parameters (isomeric shift delta = 0.

[A new open reading frame in the genome of cyanobacteria Synechocystis sp. PCC 6803].

A new open reading frame ORF242, coding for a 26.47-kDa polypeptide, was found in a DNA fragment of the cyanobacterium Synechocystis 6803, transforming a photosynthetic mutant to photoautotrophy and having homology with plant chloroplast DNA. In the 5' flanking region of ORF242, consensus sequences characteristic of a functioning gene were found.