We have investigated two approaches to enhance and extend H2 photoproduction yields in heterocystous, N2-fixing cyanobacteria entrapped in thin alginate films. In the first approach, periodic CO2 supplementation was provided to alginate-entrapped, N-deprived cells. N deprivation led to the inhibition of photosynthetic activity in vegetative cells and the attenuation of H2 production over time. ...

The toxin producing nitrogen-fixing heterocystous freshwater cyanobacterium Cylindrospermopsis raciborskii recently radiated from its endemic tropical environment into sub-tropical and temperate regions, a radiation likely to be favored by its ability to fix dinitrogen (diazotrophy). Although most heterocystous cyanobacteria differentiate regularly spaced intercalary heterocysts along their tri...

Heterocystous cyanobacteria form symbiotic associations with a wide range of plant and fungal hosts. We used a molecular phylogenetic approach to investigate the degree of host specialization of cyanobacteria associated with four closely related species of the lichenized fungus Peltigera, and to compare these strains with other symbiotic cyanobacteria. We conducted phylogenetic analyses on 16S,...

Four heterocystous cyanobacteria, isolated from grasslands of Ujjain were selected to prepare the clay based inoculants. Inoculants were evaluated for shelf life in terms of the titer value at 6 month intervals for 24 months. For colonization by inoculants in natural grasslands, the clay based inocula were applied to the field at: 40, 80 and 120 kg/ha and their survival was estimated at differe...

Biological soil crusts (biocrusts), which supply significant amounts of fixed nitrogen into terrestrial ecosystems worldwide (∼33 Tg y(-1)), are likely to respond to changes in temperature and precipitation associated with climate change. Using nifH gene-based surveys, we explored variation in the diazotrophic community of biocrusts of the Colorado Plateau, USA in response to season (autumn vs....

Natural products are a functionally diverse class of biochemically synthesized compounds, which include antibiotics, toxins, and siderophores. In this paper, we describe both the detection of natural product activities and the sequence identification of gene fragments from two molecular systems that have previously been implicated in natural product production, i.e., nonribosomal peptide synthe...

Cyanobacteria with true branching are classified in Subsection V (formerly order Stigonematales) in the phylum CYANOBACTERIA: They exhibit a high degree of morphological complexity and are known from particular biotopes. Only a few stigonematalean morphotypes have been cultured, and therefore the high variability of morphotypes found in nature is under-represented in culture. Axenic cultures of...

Heterocyst-forming cyanobacteria are important players at both evolutionary and ecological scales, but to date it has been difficult to establish their phylogenetic affiliations. We present data from a phylogenetic and molecular clock analysis of heterocystous cyanobacteria within the family Rivulariaceae, including the genera Calothrix, Rivularia, Gloeotrichia and Tolypothrix. The strains were...

Plasmid pSUP5011 contains a pMBl origin of replication, an origin of transfer (oriT), and genes encoding resistance to the antibiotics ampicillin, chloramphenicol and kanamycin. pSUP5011 was conjugally mobilized from Escherichia coli into the non-heterocystous, filamentous, nitrogen-fixing cyanobacterium Plectonema boryanum UTEX 594 in the presence of a helper plasmid, RP4. Transconjugant cyano...