A cell-free system exhibiting both photophosphorylation (P /2e = 1) and oxidative phosphoryla­ tion (P/O up to 0 .8 ) is described for the cyanobacterium Anabaena variabilis. NADH and N A D PH were found to be equally effective as electron donors for oxidative phosphorylation. Low concentrations of U H D B T , an inhibitor of the cytochrome blc complex of mitochondria and chloroplasts. were fou...

Growth of several cyanobacteria was examined on ethane sulfonate and taurine as only sulfur source. Comparing two strains with differential utilization of sulfonic acids (Anabaena variabilis and Synechococcus 6301) demonstrated that actual growth was coupled to the presence of an active sulfonate transport system due to species specific properties and nutritional conditions. Sulfonate uptake in...

Cyanobacteria are autotrophic prokaryotes with excellent antioxidative system that scavenges reactive oxygen species produced during photosynthesis. Superoxide dismutase (SOD) represent the primary defence against oxygen damage. The antioxidative activity of SOD enzymes was determined in cultures of the bloom forming cyanobacteria Anabaena variabilis and Synechococcus elongates. Experimental re...

The filamentous cyanobacterium Anabaena variabilis ATCC 29413 fixes nitrogen under aerobic conditions in specialized cells called heterocysts that form in response to an environmental deficiency in combined nitrogen. Nitrogen fixation is mediated by the enzyme nitrogenase, which is very sensitive to oxygen. Heterocysts are microxic cells that allow nitrogenase to function in a filament comprise...

UNLABELLED In the cyanobacterium Anabaena variabilis ATCC 29413, aerobic nitrogen fixation occurs in micro-oxic cells called heterocysts. Synthesis of nitrogenase in heterocysts requires expression of the large nif1 gene cluster, which is primarily under the control of the promoter for the first gene, nifB1. Strong expression of nifH1 requires the nifB1 promoter but is also controlled by RNA pr...

zinc ions are present in different types of industrial effluents, being responsible for environmental pollution. biosorption is a process in which solids of natural origin are employed for binding heavy metals. it is a promising alternative method to treat heavy metal wastes mainly because of high metal binding capacity. the effect of some important parameters on sorption capacity of cyanobacte...

The RbpA3 protein of Anabaena variabilis contains one RNA-binding domain with a carboxy-terminal glycinerich domain. Levels of two transcripts of the rbpA3 gene were differentially regulated by growth temperature. The RbpA3 protein is related to the RbpC protein within the group of cyanobacterial Rbps.

We have determined that the type II restriction enzyme Ava II, isolated from Anabaena variabilis, recognizes and cuts the sequence (formula: see article). The eight Ava II sites of pBR322 have been mapped, as well as a unique site for Ava I.

When incubated anaerobically, in the light, in the presence of C2H2 and high concentrations of H2, both Mo-grown Anabaena variabilis and either Mo- or V-grown Anabaena azotica produce large amounts of H2 in addition to the H2 initially added. In contrast, C2H2-reduction is diminished under these conditions. The additional H2-production mainly originates from nitrogenase with the V-enzyme being ...

The chlorophyll-containing lamellar structures isolated from Anabaena variabilis have the ability to oxidize reduced mammalian cytochrome c in the dark. This activity is oxygen dependent and heat labile. As with other cytochrome oxidase preparations, activity is stimulated by detergents and is sensitive to the ionic strength of the assay solution. The cytochrome oxidase activity is not inhibite...