Using crude extracts from the cyanobacterium Anabaena variabilis glutamine synthetase (GS) activity was rapidly irreversibly reduced to about 60% during dark incubation („sponta­ neous GS inactivation“). An additional decrease was observed by the addition of ammonia in the light („ammonia-mediated inactivation“). Both effects were prevented by EDTA, MnCl2 or catalase indicative of the involveme...

A method is described for the preparation of thylakoids from the blue-green alga Anabaena variabilis which exhibit photosynthetic control. The thylakoids can be stored in liquid N 2 with little loss in activity. P /e2 ratios (number of ATP molecules formed per pair of electrons transported) have been determined for partial reactions of the photosynthetic electron transport chain. Electron trans...

Photosynthesis, Respiration, Blue-Green Algae, Arrhenius Plots, Phase Transition Temperatures Photosynthetic and respiratory electron-transport reactions by the blue-green alga, Anabaena variabilis, exhibit a strict temperature dependence in vivo as well as in the cell-free system. The ratio of respiratory oxygen uptake in the dark and oxygen evolution in the light is high after growth at low t...

Sinorhizobium meliloti cells were engineered to overexpress Anabaena variabilis flavodoxin, a protein that is involved in the response to oxidative stress. Nodule natural senescence was characterized in alfalfa (Medicago sativa) plants nodulated by the flavodoxin-overexpressing rhizobia or the corresponding control bacteria. The decline of nitrogenase activity and the nodule structural and ultr...

Lysine biosynthesis in bacteria and plants commences with a condensation reaction catalysed by dihydrodipicolinate synthase (DHDPS) followed by a reduction reaction catalysed by dihydrodipicolinate reductase (DHDPR). Interestingly, both DHDPS and DHDPR exist as different oligomeric forms in bacteria and plants. DHDPS is primarily a homotetramer in all species, but the architecture of the tetram...

Cyanobacteria contribute significantly to the maintenance of flooded rice field fertility. In this investigation, the protective effect of osmolytes and antioxidative enzymes was studied on the paddy field cyanobacterial biofertilizer; Anabaena variabilis exposed to Malathion pesticide. With increasing concentration of malathion the test organism showed increased free radical mediated toxicity....

The Mycobacterium tuberculosis enhanced intracellular survival (Eis_Mtb) protein is a clinically important aminoglycoside (AG) multi-acetylating enzyme. Eis homologues are found in a variety of mycobacterial and non-mycobacterial species. Variation of the residues lining the AG-binding pocket and positions of the loops bearing these residues in the Eis homologues dictates the substrate specific...

In this study herpes simplex virus type 1-encoded ribonucleotide reductase was shown to be able to utilize thioredoxin purified from the cyanobacterium Anabaena variabilis as a hydrogen donor for the enzyme. An assay has been developed to search for proteins which can function as a hydrogen donor for the viral ribonucleotide reductase. A protein has been identified and purified to homogeneity f...

In many filamentous cyanobacteria nitrogen fixation occurs in differentiated cells called heterocysts. Filamentous strains that do not form heterocysts may fix nitrogen in vegetative cells, primarily under anaerobic conditions. We describe here two functional Mo-dependent nitrogenases in a single organism, the cyanobacterium Anabaena variabilis. Using a lacZ reporter with a fluorescent beta-gal...

Salt-induced genes in the cyanobacterium Anabaena sp. strain PCC 7120 were identified by use of a Tn5-based transposon bearing luxAB as a reporter. The genomic sequence adjacent to one site of insertion of the transposon was identical in part to the sequence of the lti2 gene, which was previously identified in a differential screen for cold-induced transcripts in Anabaena variabilis. The lti2-l...