Species Of Calothrix Research Articles

The GeneraCalothrixAgardh ex Bornet et Flahault,GloeotrichiaJ. Agardh ex Bornet et Flahault andRivularia(Roth) C. Agardh ex Bornet et Flahault (Cyanoprokaryota: Nostocales) in West Bengal, India

West Bengal has much suitable habitat for heterocystous Cyanoprokaryota but the work done in this state is insufficient. Therefore, area wise and group wise floristic work has been un-dertaken. In this communication three genera namely Calothrix, Gloeotrichia and Rivularia from Hooghly district have been presented. Calothrix is represented by 6 species, Gloeotrichia by 4 species and Rivularia by one species. Of these five species of Calothrix and one species of Gloe-otrichia are new records for algal flora of West Bengal.

Distribution and ecology of cyanobacteria in the rocky littoral of an english lake district water body, devoke water.

Cyanobacteria were sampled along two vertical and two horizontal transects in the littoral of Devoke Water, English Lake District. Profiles of cyanobacterium diversity and abundance showed that both attained a maximum close to the water line, but declined rapidly 20–40 cm above it. The distribution of individual species with height together with species and site ordinations showed that several taxa occurred in well-defined zones. A narrow “black zone” in the supralittoral was colonised mainly by species of Calothrix, Dichothrix and Gloeocapsa with pigmented sheaths. There was no evidence of lateral variation of species around the lake, but the height of the black zone correlated positively with wind exposure. The flora of Devoke Water is that of a base-poor mountain lake with some elements of a lowland, more alkaline water-body.

Morphological and genetic diversity of symbiotic cyanobacteria from cycads

The morphological and genetic diversity of cyanobacteria associated with cycads was examined using PCR amplification techniques and 16S rRNA gene sequence analysis. Eighteen symbiotic cyanobacteria were isolated from different cycad species. One of the symbiotic isolates was a species of Calothrix, a genus not previously reported to form symbioses with Cycadaceae family, and the remainder were Nostoc spp. Axenic cyanobacterial strains were compared by DNA amplification using PCR with either short arbitrary primers or primers specific for the repetitive sequences. Based on fingerprint patterns and phenograms, it was revealed that cyanobacterial symbionts exhibit important genetic diversity among host plants, both within and between cycad populations. A phylogenetic analysis based on 16S rRNA gene sequence analysis revealed that most of the symbiotic cyanobacterial isolates fell into well-separated clades.

Phenotypic and genotypic comparison of symbiotic and free-living cyanobacteria from a single field site

PCR amplification techniques were used to compare cyanobacterial symbionts from a cyanobacterium-bryophyte symbiosis and free-living cyanobacteria from the same field site. Thirty-one symbiotic cyanobacteria were isolated from the hornwort Phaeoceros sp. at several closely spaced locations, and 40 free-living cyanobacteria were isolated from the immediate vicinity of the same plants. One of the symbiotic isolates was a species of Calothrix, a genus not previously known to form bryophyte symbioses, and the remainder were Nostoc spp. Of the free-living strains, two were Calothrix spp., three were Chlorogloeopsis spp. and the rest were Nostoc spp. All of the symbiotic and all but one of the free-living strains were able to reconstitute the symbiosis with axenic cultures of both Phaeoceros and the liverwort Blasia sp. Axenic cyanobacterial strains were compared by DNA amplification using PCR with either short arbitrary primers or primers specific for the regions flanking the 16S-23S rRNA internal transcribed spacer. With one exception, the two techniques produced complementary results and confirmed for the first time that a diversity of symbiotic cyanobacteria infect Phaeoceros in the field. Symbionts from adjacent colonies were different as often as they were the same, showing that the same thallus could be infected with many different cyanobacterial strains. Strains found to be identical by the techniques employed here were often found as symbionts in different thalli at the same locale but were never found free-living. Only one of the free-living strains, and none of the symbiotic strains, was found at more than one sample site, implying a highly localized distribution of strains.

The identification of the coralloid root endophytes of the southern African cycads and the ability of the isolates to fix dinitrogen

Forty-one isolates of the cyanobionts in the coralloid roots of 31 cycad species, which include all the species indigenous to the Republic of South Africa, were identified. One isolate (from Encephalartos hildebrandtii ) appears to be a species of Calothrix . All the other isolates were identified as species of Nostoc . Twenty-eight isolates were assigned to N. commune , five to N. punctiforme , two each to N. ellipsosporum , N. paludosum and N. sphaericum whilst one isolate was identified as N. muscorum . In the case of two cycad species, isolates were made from more than one individual. Of the 10 isolates from seven individuals of Encephalartos transvenosus eight were N. commune and two N. paludosum . One of the two isolates from Encephalartos manikensis was N. ellipsosporum and the other N. punctiforme . One isolate from each cycad species was shown to reduce acetylene to ethylene. One isolate from each of twelve cycad species was tested for its ability to fix 15 N. All yielded positive results. Although the cyanobacteria in all the isolates tested for acetylene reduction were contaminated with other bacteria (which were not identified), it could be demonstrated that they did not contribute to the nitrogenase activity of the cyanobiont cultures. Een-en-veertig sianobiontisolate uit die koraalvormige wortels van 31 broodboomspesies, wat al die spesies wat inheems aan die Republiek van Suid-Afrika is insluit, is geïdentifiseer. Een isolaat (vanuit Encephalartos hildebrandtii ) is skynbaar ’n Calothrix spesie. Al die ander isolate is as spesies van Nostoc geïdentifiseer. Agt-en-twintig isolate is as N. commune uitgeken, vyf as N. punctiforme , twee elk as N. ellipsosporum , N. paludosum en N. sphaericum en een as N. muscorum . Van twee broodboomspesies is isolate vanuit meer as een individu gemaak. Van die 10 isolate uit sewe Encephalartos transvenosus individue, is agt as N. commune en twee as N. paludosum uitgeken. Een van die twee isolate uit Encephalartos manikensis was N. ellipsosporum en die ander N. punctiforme . Een sianobiontisolaat van elke broodboomspesie is vir asetileenreduksie getoets terwyl een isolaat van elk van 12 broodboomspesies vir 15 N-binding getoets is. In al die gevalle is duidelike positiewe resultate verkry. Alhoewel al die isolate wat vir asetileenreduksie getoets is, naas sianobakterieë ook ander bakterieë, wat nie geïdentifiseer is nie, bevat het, kon daar aangetoon word dat laasgenoemde bakterieë nie tot die nitrogenase-aktiwiteit van die kulture bygedra het nie.

Complete amino acid sequence of cyanobacterial gas-vesicle protein indicates a 70-residue molecule that corresponds in size to the crystallographic unit cell.

Gas vesicles of cyanobacteria are formed by a protein called 'gas-vesicle protein' (GVP). The complete amino acid sequence has been determined of GVP from Anabaena flos-aquae. It is 70 residues long and has an Mr of 7388. This corresponds to the size of the repeating unit cell demonstrated by X-ray crystallography of intact gas vesicles. Details of the sequence are related to the secondary beta-sheet structure of the protein and its contrasting hydrophilic and hydrophobic surfaces. Extensive amino acid sequences have also been determined for GVPs from two other cyanobacteria, species of Calothrix and Microcystis; they are highly homologous with that of Anabaena GVP. Electrophoretic analysis indicates that GVPs of different cyanobacteria form a variety of stable oligomers.

Uptake of Sodium and Potassium by Blue-Green Algae (Cyanobacteria)

Summary Tolypothrix ceylonica, Hapalosiphon intricatus, and two species of Calothrix (C. braunii and C. membranacea) showed absorption of sodium > 0.8 μg/mg algae dry wt., grown in a medium containing 1.425 mg Na/ml. These species of blue-green algae synthesized less biomass as compared to the species of Scytonema, Nostoc, Calothrix, and Aulosira. On supplementing the medium with graded concentration of potassium, a reduced Na/K ratio was observed, and the biomass production increased as the concentration of potassium increased up to a limit of 0.13 mg K/ml. No definite trend with protein synthesis could be observed.

Nitrogen fixation by blue-green algae in Yellowstone thermal areas

Abstract Potential nitrogen-fixing blue-green algae were common in three hot spring streams studied in Yellowstone National Park. In two streams, where the dominant nitrogen-fixing algae were species of Calothrix, nitrogen fixation, as measured by uptake of 15N2, was detected in situ in the temperature range 28–46 C. At higher temperatures nitrogen fixation was not detected, although the algae may have received fixed nitrogen from a growth of Calothrix, Nostoc, and unicellular algae which occurred at lower temperatures on the sides of the streams. In the third stream, where Mastigocladus was abundant, nitrogen fixation was detected at temperatures up to 54 C, although the optimum for fixation was near 42.5 C. The overall data imply that in situ nitrogen fixation contributes to the productivity of Yellowstone hot spring regions and that Mastigocladus and Calothrix are the most important nitrogen-fixing blue-green algae.

CULTURALLY INDUCED VARIATION IN FOUR MORPHOLOGICALLY DIVERSE BLUEGREEN ALGAE

Characters used in taxonomic placement at levels from family to species appeared, disappeared, or varied widely, while others remained constant, in cultures of four disparate species of blue‐green algae (Cyanophyta) under varying conditions of culture. Species of Anabaena and Gloeocapsa displayed fairly stable characteristics. Species of Calothrix and Lyngbya exhibited much greater variability, especially in twisting of filaments, presence or absence of constrictions at the cross walls, abundance of heterocysts, pseudovacuoles, fragmentation of filaments, and change of color. Color change was associated with abrupt pH shift in Lyngbya and could be reversed by adding nitrate. In the putatively nitrogen‐fixing Anabaena, similar change in color with age was not associated with sharp pH shift, nor could it be reversed with nitrate. In general, growth on agar in turbulent conditions and with decreased CO2–O2 exchange was less than that obtainable under other conditions, and media with acid pH were partially or totally inhibitory to growth.

Culturally Induced Variation in Four Morphologically Diverse Bluegreen Algae

Characters used in taxonomic placement at levels from family to species appeared, disappeared, or varied widely, while others remained constant, in cultures of four disparate species of blue-green algae (Cyanophyta) under varying conditions of culture. Species of Anabaena and Gloeocapsa displayed fairly stable characteristics. Species of Calothrix and Lyngbya exhibited much greater variability, especially in twisting of filaments, presence or absence of constrictions at the cross walls, abundance of heterocysts, pseudovacuoles, fragmentation of filaments, and change of color. Color change was associated with abrupt pH shift in Lyngbya and could be reversed by adding nitrate. In the putatively nitrogen-fixing Anabaena, similar change in color with age was not associated with sharp pH shift, nor could it be reversed with nitrate. In general, growth on agar in turbulent conditions and with decreased CO2–O2 exchange was less than that obtainable under other conditions, and media with acid pH were partially or totally inhibitory to growth.