Cyanobacteria are photosynthetic prokaryotic organisms that in aquatic environments can compose the phytoplankton and phytobenthos, being important primary production of these ecosystems. The objective this work was to identify main morphological variations cells, filaments thallus cyanobacteria Nostoc sp. LBALBR-2 submitted ultraviolet radiation (UV-C) microcosm systems. subjected four treatme...

The fine structure of Cyanidium caldarium, as seen in thin sections of KMnO(4)-fixed cells examined with the electron microscope, is described. This organism, whose taxonomic position among algae is undetermined, contains a single well defined chloroplast, a nucleus, and mitochondria. Studies, with the electron microscope, of Chlorella pyrenoidosa and Nostoc are also reported. Structural differ...

Cyanobacterial tRNA(Leu) (UAA) intron sequences from natural populations of Nostoc and other cyanobacteria were compared. Variation between the different introns was not randomly distributed but strongly restricted by the secondary and tertiary structure of the intron. Although all Nostoc sequences examined shared high similarity, differences were observed in one stem-loop. This stem-loop could...

Cold, dry, and nutrient-poor, the McMurdo Dry Valleys of Antarctica are among most extreme terrestrial environments on Earth. Numerous studies have described microbial communities low elevation soils streams below glaciers, while less is known about in higher above glaciers. We characterized life four landscape features (habitats) a mountain Taylor Valley. These habitats varied significantly so...

Cyanobacterial diazotrophs play a significant role in environmental nitrogen economy despite their habitat either tropical or polar. However, the phenomenon by which it copes with temperature induced stress is poorly understood. Temperature response study of psychrophilic and mesophilic Nostoc strains explores their adaptive mechanisms. The selected psychrophilic and mesophilic strains were con...