As an approach towards elucidation of the biochemical regulation of the progression of heterocyst differentiation in Anabaena sp. strain PCC 7120, we have identified proteins that bind to a 150-bp sequence upstream from hepC, a gene that plays a role in the synthesis of heterocyst envelope polysaccharide. Such proteins were purified in four steps from extracts of vegetative cells of Anabaena sp...

Filamentous cyanobacteria of the genus Anabaena contain a unique open reading frame, rbcX, which is juxtaposed and cotranscribed with the genes (rbcL and rbcS) encoding form I ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO). Plasmid constructions containing the genes from Anabaena sp. strain CA were prepared, and expression studies in Escherichia coli indicated that the product of the...

An appraisal of the current ecological status Asejire Reservoir was carried out using reservoir phytoplankton composition and community structure. Monthly sampling in nine selected sites for twelve months. Data were analysed descriptive statistics, analysis variance, Shannon-Weiner Evenness indices. One hundred fifty-four taxa identified. Taxa dominance following order: Bacillariophycea>Chlorop...

The present study was carried out in order to examine and characterize the bidirectional hydrogenase in the cyanobacterium Nostoc sp. strain PCC 73102. Southern hybridizations with the probes Av1 and Av3 (hoxY and hoxH, bidirectional hydrogenase small and large subunits, respectively) revealed the occurrence of corresponding sequences in Anabaena variabilis (control), Anabaena sp. strain PCC 71...

Anabaena variabilis grows heterotrophically using fructose, while the close relative Anabaena sp. strain PCC 7120 does not. Introduction of a cluster of genes encoding a putative ABC transporter, herein named frtRABC, into Anabaena sp. strain PCC 7120 on a replicating plasmid allowed that strain to grow in the dark using fructose, indicating that these genes are necessary and sufficient for het...

Redox regulation based on disulfide-dithiol conversion catalyzed by thioredoxins is an important component of chloroplast function. The reducing power is provided by ferredoxin reduced by the photosynthetic electron transport chain. In addition, chloroplasts are equipped with a peculiar NADPH-dependent thioredoxin reductase, termed NTRC, with a joint thioredoxin domain at the carboxyl terminus....

Catalases are ubiquitous enzymes that detoxify H2O2 in virtually all organisms exposed to oxygen. The filamentous, nitrogen-fixing cyanobacterium, Anabaena PCC 7120, shows the presence of 2 genes (katA and katB) that encode Mn-catalases. We have recently shown that pre-treatment of Anabaena with NaCl causes substantial induction of the KatB protein, which consequently leads to increased oxidati...

Anatoxin-a (ATX) is a potent neurotoxin produced by several species of Anabaena spp. Cyanobacteria blooms around the world have been increasing in recent years; therefore, it is urgent to develop sensitive techniques that unequivocally confirm the presence of these toxins in fresh water and cyanobacterial samples. In addition, the identification of different ATX analogues is essential to later ...

Cyanobacteria are photosynthetic prokaryotes found in a range of environments. They are infamous for the production of toxins, as well as bioactive compounds, which exhibit anticancer, antimicrobial and protease inhibition activities. Cyanobacteria produce a broad range of antifungals belonging to structural classes, such as peptides, polyketides and alkaloids. Here, we tested cyanobacteria fro...