BACKGROUND Cyanobacteria are recognized as the primordial organisms to grace the earth with molecular oxygen ~3.5 billion years ago as a result of their oxygenic photosynthesis. This laid a selection pressure for the evolution of antioxidative defense mechanisms to alleviate the toxic effect of active oxygen species (AOS) in cyanobacteria. Superoxide dismutases (SODs) are metalloenzymes that ar...

Abstract Heterocystous Cyanobacteria of the genus Nodularia form major blooms in brackish waters, while terrestrial Nostoc species occur worldwide, often associated biological soil crusts. Both genera, by virtue their ability to fix N 2 and conduct oxygenic photosynthesis, contribute significantly global primary productivity. Select produce hepatotoxin nodularin whether its production will chan...

Photosynthetic bacteria, such as Rhodopseudomonas capsulata, when incubated in the light under conditions of nitrogen starvation, produce copious amounts of hydrogen gas via nitrogenase, presumably as a means of regulating their energy charge and/or redox balance and thereby preventing photooxidative damage until growth can begin again [1,2]. A similar role has been suggested for the hydrogenas...

Nitrogen fixation blue-green algae make a major contribution to the fertility of soil. It has been suggested that blue-green algae (BGA) assist higher plant growth by supplying growth substances. There are numerous works about roles of blue-green algae in paddy soils and rice growth but little on other plants. In this research, 19 morphospecies belonging to three families of heterocystous and n...

Sandusky Bay experiences annual toxic cyanobacterial blooms dominated by Planktothrix agardhii/suspensa. To further understand the environmental drivers of these events, we evaluated changes in the growth response and toxicity of the Planktothrix-dominated blooms to nutrient amendments with orthophosphate (PO4) and inorganic and organic forms of dissolved nitrogen (N; ammonium (NH4), nitrate (N...

Background: Cyanobacteria have a worldwide distribution in the terrestrial habitats, occurring predominantly on the surface of the soils, stones, rocks, and trees, practically in moist, neutral or alkaline aeries. The unique natural and bioactive compounds from cyanobacteria with various biological activities and an extensive range of chemical classes have a significant capabil...

Alkaline phosphatase (phosphomonoesterase i.e. PMEase) activity in heterocystous cyanobacteria Anabaena flos-aquae, Nostoc calcicola, Calothrix brevissima, Scytonema javanicum and Hapalosiphon intricatus is known to be temperature and pH dependent. Maximum level of enzyme activity was recorded at either 35 degrees C or 37.5 degrees C. Also, the cell bound phosphomonoesterase enzyme was shown to...

Cyanobacterial ; blooms are a regular feature of lakes in central North America, but little is known of their importance to the nitrogen (N) cycle and nutrition of aquatic food webs. We hypothesized that N2-fixing cyanobacteria constitute a significant source of N to prairie lakes, that fixed N is effectively transferred to primary and secondary consumers, and that the importance of fixed N is ...

The objective of this study was to characterize the community structure and activity of N2-fixing microorganisms in mature and poorly developed biological soil crusts from both the Colorado Plateau and Chihuahuan Desert. Nitrogenase activity was approximately 10 and 2.5 times higher in mature crusts than in poorly developed crusts at the Colorado Plateau site and Chihuahuan Desert site, respect...