Cyanobacterial blooms in freshwaters represent a major ecological and human health problem worldwide. This paper briefly summarizes information on major cyanobacterial toxins (hepatotoxins, neurotoxins etc.) with special attention to microcystins-cyclic heptapeptides with high acute and chronic toxicities. Besides discussion of human health risks, microcystin ecotoxicology and consequent ecolog...

BACKGROUND Biliverdin IXα is produced when heme undergoes reductive ring cleavage at the α-methene bridge catalyzed by heme oxygenase. It is subsequently reduced by biliverdin reductase to bilirubin IXα which is a potent endogenous antioxidant. Biliverdin IXα, through interaction with biliverdin reductase, also initiates signaling pathways leading to anti-inflammatory responses and suppression ...

The freshwater cyanobacteria, Microcystis sp., commonly form large colonies with bacteria embedded in their mucilage. Positive and negative interactions between Microcystis species and their associated bacteria have been reported. However, the potential role of bacteria in the production and degradation of cyanobacterial secondary metabolites has not been investigated. In this study, a Microcys...

The potential utilization of cyanobacteria for the biological production of alkanes represents an exceptional system for the next generation of biofuels. Here, we analyzed a diverse group of freshwater and marine cyanobacterial isolates from Indian culture collections for their ability to produce both alkanes and alkenes. Among the 50 cyanobacterial isolates screened, 32 isolates; 14 freshwater...

Harmful cyanobacterial blooms are of increasing global concern and their prediction and management requires an improved understanding of the controlling factors for cyanobacterial growth and dominance. In Lake St Charles, the drinking water supply for Quebec City, Canada, harmful cyanobacterial blooms were first recorded in autumn 2006. Our aims were to define the temporal and spatial variation...

Cyanobacteria represent a common component of algal assemblages in Florida's lakes, springs, estuaries, and other marine environments. The frequency of cyanobacterial bloom reports has recently become more common and algal toxin data are just beginning to be collected with the advent of monitoring efforts and the availability of laboratories in the state capable of conducting algal toxin analys...

If Mg(2+) ion is replaced by Mn(2+) ion, RNA polymerase tends to misincorporate noncognate nucleotide, which is thought to be one of the reasons for the toxicity of Mn(2+) ion. Therefore, most cells have Mn(2+) ion at low intracellular concentrations, but cyanobacteria need the ion at a millimolar concentration to maintain photosynthetic machinery. To analyse the mechanism for resistance agains...

The gene (ppc) coding for phosphoenolpyruvate carboxylase (PEPCase) in the cyanobacterium Synechococcus PCC 7942 has been inactivated via insertional mutagenesis while being functionally complemented by Escherichia coli ppc. Cyanobacterial cells functionally complemented by E. coli ppc showed decreased PEPCase activity in crude cell lysates and detergent-permeabilized whole cell assays. Decreas...

Microcystis bloom, a cyanobacterial mass occurrence often found in eutrophicated water bodies, is one of the most serious threats to freshwater ecosystems worldwide. In nature, Microcystis forms aggregates or colonies that contain heterotrophic bacteria. The Microcystis-bacteria colonies were persistent even when they were maintained in lab culture for a long period. The relationship between Mi...