Membranes isolated from heterocysts and vegetative cells of Anabaena 7120 were assayed for content of cytochrome f, cytochrome b-563, cytochrome b-559(HP), cytochrome b-559(LP), and cytochrome aa(3) by use of reduced-minus-oxidized difference spectra. The level of cytochrome aa(3) in heterocyst membranes was 4 to 100 times higher than that in vegetative cells of Anabaena 7120 or other species o...

This is an investigation concerned with studying the possible adaptive response of four different unicellular algae, Anabaena PCC 7120, Oscillatoria angustissima, Scendesmus obliquus and Chlorella vulgaris, to the toxin of Microcystis aeruginosa (Kützing). The effects of four different concentrations, 25, 50, 100 and 200 μg mL-1 of microcystins crude extract of M. aeruginosa, on both intra and ...

Light-induced proton efflux of Anabaena variabilis was found to be biphasic, the second phase being inhibited by the ATPase inhibitor nitrofen (2,4-dichloro-1-[4-nitrophenoxy]benzene). The first, fast phase was triggered by monochromatic light of 707 nanometers, whereas the second, slower phase was not. With 707 nanometers, light, respiratory O(2) uptake was inhibited. Using light composed of t...

Inactivation of sll0861 in Synechocystis sp. strain PCC 6803 or the homologous gene alr2432 in Anabaena sp. strain PCC 7120 had no effect on the growth of these organisms at a light intensity of 30 micromol photons m(-2) s(-1) but reduced their growth at a light intensity of 5 or 10 micromol photons m(-2) s(-1). In Anabaena, inactivation of the gene also significantly reduced the rate of hetero...

Anabaena sp. strain PCC 7120 is a filamentous cyanobacterium that fixes N(2) in specialized cells called heterocysts, which differentiate from vegetative cells in a process that requires the nitrogen control transcription factor NtcA. 2-Oxoglutarate-stimulated binding of purified NtcA to wild-type and modified versions of the ntcA gene promoter from Anabaena sp. was analyzed by mobility shift a...

The cyanobacterium Anabaena flos-aquae (strain 1444) grown at different intensities o f white light (900. 3500 and 30000 lux) showed changes in the content and com position o f the pigments. Phycocyanin was more affected by high light conditions during growth than chlorophyll a. In comparison to in low white light grown cyanobacteria number o f phycobilisom es and thylakoids decreased under str...

Randomly amplified polymorphic DNA PCR was used to generate unique and identifying DNA profiles for members of the cyanobacterial genera Anabaena and Microcystis, which are responsible for much of the production of nuisance blooms in various freshwater systems, including recreational and drinking water supplies. A method based on the combination of two 10-mer oligonucleotides in a single PCR wa...

Two transport systems for L-arginine were evident in Anabaena sp. strain PCC 7120: a high-affinity one (Km, 1.7 microM) that accumulated arginine within the cells through an energy-requiring process and another one that exhibited low affinity for L-arginine (Km, 0.75 mM) and was unable to accumulate the substrate. Both systems were inhibited by L-canavanine, L-lysine, and L-ornithine. Two syste...

Higher plants process two distinct, nuclear gene-encoded glyceraldehyde-3-phosphate dehydrogenase (GAPDH) proteins, a Calvin-cycle enzyme active within chloroplasts and a glycolytic enzyme active within the cytosol. The gene for the chloroplast enzyme was previously suggested to be of endosymbiotic origin. Since the ancestors of plastids were related to cyanobacteria, we have studied GAPDH gene...