Nostoc Species Research Articles

APPLICATION OF GAS‐LIQUID CHROMATOGRAPHY TO STUDY OF THE ENVELOPE LIPIDS OF HETEROCYSTS12

SUMMARYGas‐liquid chromatography of algal extracts provides a sensitive assay for their content of 1‐(O‐α‐d‐glycopyranosyl)‐3, 25‐hexacosanediol, the principal glycolipid from the envelope of heterocysts of Anabaena cylindrica. Different patterns of lipids were found in the heterocysts of 5 species of Anabaena and Nostoc. Lipids with comparable chromatographic properties were detected in Gloeocapsa.

Phycobilisomes from a blue-green alga Nostoc species.

Phycobilisomes were isolated from a Nostoc sp. strain Mac in phosphate buffer (pH 7.0) by treatment with 1% Brij 56 and centrifugation on discontinuous sucrose gradients (2.0, 1.0, 0.5, and 0.25 M in the proportions 6:4:4:10 ml, respectively). Absorption spectra of isolated phycobilisomes showed the presence of phycoerythrin, phycocyanin, and allophycocyanin. The phycobilisome pigments were partially resolved by electrophoresis on acrylamide gels. Stained gels demonstrated that each main protein band corresponded to a pigmented region. The phycobilisomes appeared compact with a rounded surface and flattened base (about 40-nm diameter) at the attachment site to the photosynthetic lamellae. Fixation in glutaraldehyde caused a significant reduction in total pigment absorption, as well as shifts in the absorption maxima, particularly that of phycoerythrin.

Dark heterotrophic growth of an endophytic blue-green alga

0768 09 1. An axenic culture of a species of Nostoc from the coralloid roots of the cycad Macrozamia lucida, grows heterotrophically in complete darkness at measurable and reproducible rates. 2. Heterotrophic growth was supported by glucose, fructose and sucrose over the pH range 6 to 9. The growth rate with glucose was increased if casamino acids were added. 3. Heterotrophic growth on glucose proceeded under both aerobic and anaerobic conditions. 4. Cultures grown in the dark were pigmented. There was no significant difference in the ultrastructure of photoautotrophically-grown and dark heterotrophically grown cells.

Peptide chain initiation in a species of Nostoc and in chloroplasts of Euglena gracilis

Peptide chain initiation in a species of Nostoc and in chloroplasts of Euglena gracilis

NITROGEN METABOLISM IN LICHENS

SummaryNitrogen fixation has been demonstrated to occur in the cephalodia of the lichen Peltigera aphthosa which contain a species of Nostoc. The rate of fixation is very high in comparison with the maximum rates for N. muscorum under optimum culture conditions. Virtually all of the nitrogen fixed is secreted to the lichen thallus at a rate equal to the rate of fixation. The possible control mechanisms of this secretion are discussed.

Production of axemic cultures of soil-borne and endophytic blue-green algae.

SUMMARY: A relatively rapid and reliable method is described for producing axenic cultures of soil-borne blue-green algae, of the blue-green algal endophytes of certain cycads, and the blue-green endophyte of the angiosperm Gunnera chilensis Endl. It was based on the micro-manipulation of hormogonia and akinetes, from which axenic cultures were propagated. Micromanipulation was done during growth in impure culture on an agar medium. The technique was used to obtain axenic cultures of fifteen soil isolates, the endophytes of the cycads Macrozamia lucida (Linnaeus) Johnson, Encephalartos altensteinii Lehm., and Bowenia serrulata Bull, and the endophyte of Gunnera chilensis Endl. The soil isolates have been tentatively identified as species of the genera Nostoc, Anabaena, Calothrix, Scytonema, Wollea, Microchaete, and Oscillatoria.

Cellular Factors Affecting Nitrogen Fixation in the Blue-Green Alga Chlorogloea fritschii

Summary: Synchronous cultures of a nitrogen-fixing blue-green alga, hitherto known as Chlorogloea fritschii but more probably an anomalous species of the genus Nostoc, were obtained by a combination of light and temperature treatments. Variation in dimensions, dry weight, pigment content and total nitrogen content of cells was followed during the development of synchronous cultures. The nitrogen-fixing activity was greatest in the small-celled filaments which develop from the endospores and predominate during exponential growth of the alga in cultures of limited volume. Strains of the alga produced by repeated exposure to X-rays, ultraviolet radiation, or sublethal concentrations of colchicine or urethane, were found to have lower rates of nitrogen fixation per unit dry weight than the original strain but liberated relatively more extracellular nitrogenous products.

On the method of integration of tidal equations suggested by Fairbrain. : Stretenski, L.N. 1962 Izv. Akad. Nauk, USSR, Geofiz. S. (7): 947–954. 7: 604–609.

Many archaeologically important stone temples, caves, mortar monuments with artistic expression as well as building facades of India are now disfigured due to colonization of cyanobacterial biofilms leading to weathering of the substratum. They are composed of species principally belonging to the genera Hassallia, Tolypothrix, Scytonema, Lyngbya and Calothrix, which appeared soon after wetting of the biofilms. Several other species of genera Aulosira, Nostoc, Camptylonema, Dichothrix, Chlorogloeopsis and Westiellopsis occurred as associated organisms as they appeared upon prolonged culture of the biofilms. Molecular phylogenetic analysis based on 16S rRNA partial gene sequencing of all these 24 cyanobacteria species under 11 genera isolated from the surfaces of monuments and building facades of India along with those of other species isolated from stone surfaces in subaerial habitats and hypogeal environments in different regions of the globe showed that those species from tropical regions were clustered together, quite different from cyanobacteria of the genera Chroococcidiopsis, Leptolyngbya, Phormidium, Nostoc, Rexia, Symphyonemopsis, Scytonema, Tolypothrix and Calothrix occurring in the temperate regions.

Reclamation of ‘Usar’ Lands in India through Blue-green Algæ

WHILE other plants, including crops, fail to grow on the alkaline ‘Usar’ lands of northern India, blue-green algae form a thick stratum on the surface of the soil during the rainy season (from July to September) and during the retreating monsoon (December–January). The most important algae are species of Nostoc (N. commune, N. muscorum, N. punctiforme), Scytonema (S. ocellatum, S. javanicum), Microcoleus (M. chthonoplastes, M. vaginatus), Porphyrosiphon (P. Notarisii), Camptylonema (C. lahorense), and Cylindrospermum (C. licheniforme, C. muscicola). In later stages, when the soil is waterlogged, forms like Aulosira fertilissima, various species of Anabœna, Cylindrospermum gorakhporense and Wollea Bharadwajœ make their appearance. Nostoc commune, which covers many miles, fulfils an especially striking role. The annual addition of organic matter to the soil is of the order of 36.5–59.7 per cent and that of nitrogen, 30–38.4 per cent. Although the nitrogen-fixing capacity of Nostoc commune and of other species is still being investigated in bacteria-free cultures, results so far obtained suggest such fixation, which has already been established in certain forms1–4. The numbers of Azotobacter appear to be considerably reduced in these soils.