Nostoc sphaeroides Kuetzing has been used as a traditional medicine in China to treat a variety of ailments. This research identified the antioxidant activities of polysaccharide extract from Nostoc sphaeroides. The extract, which contains 46.2% carbohydrates, exhibited an effective scavenging capability on superoxide radical, hydroxyl radicals in non site-specific as well as site-specific assa...

Two species of thalloid liverworts, Blasia pusilla and Cavicularia densa, form stable symbioses with nitrogen-fixing cyanobacteria. Both bryophytes promote the persistence of their cyanobacterial associations by producing specialized gemmae, which facilitate the simultaneous dispersal of the host and its nitrogen-fixing symbionts. Here the genetic diversity of cyanobacterial symbionts of Blasia...

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...

Nostoc is a cyanobacterial genus, common in soils and a prolific producer of natural products. This research project aimed to explore and characterize Brazilian cyanobacteria for new bioactive compounds. Here we report the production of hepatotoxins and new protease inhibitors from benthic Nostoc sp. CENA543 isolated from a small, shallow, saline-alkaline lake in the Nhecolândia, Pantanal wetla...

Cyanobacteria are characterized as oxygenic photoautotrophs and use the reductive pentose phosphate (CalvinBenson) cycle in assimilation of C02. Based on enzyme assays and isotopic labeling experiments, a11 cyanobacteria are assumed to use reactions of the oxidative pentose phosphate pathway to generate reductant for maintenance energy in the dark period of natural diel cycles (Smith, 1983). In...

Pure cultures of the symbiotic cyanobacterium-bryophyte association with Anthoceros punctatus were reconstituted by using Nostoc sp. strain UCD 7801 or its 3-(3,4-dichlorophenol)-1,1-dimethylurea (DCMU)-resistant mutant strain, UCD 218. The cultures were grown under high light intensity with CO2 as the sole carbon source and then incubated in the dark to deplete endogenous reductant pools befor...

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...