Morphological and physiological modifications of cyanobacteria in experimental cyanobacterium-actinomycete associations

Autor: G. M. Nikolaev, I. B. Savelyev, G. M. Zenova, Elena Lobakova, E.O. Omarova, D. G. Zvyagintsev, Ekaterina Ivanova
Rok vydání: 2010
Předmět:
Zdroj: Microbiology. 79:314-320
ISSN: 1608-3237
0026-2617
DOI: 10.1134/s0026261710030069
Popis: Associations of cyanobacteria and actinomycetes were formed experimentally from the cyanobacterium Anabaena variabilis ATCC 29413 and the streptomycetes isolated from apogeotropic roots of sago plants. Based on their phenotypic properties and the 16S rRNA gene sequencing, the streptomycetes were identified as representatives of Streptomyces pluricolorescens (strains 1 and 2). Cyanobacteria developing in monoculture and in association with an actinomycete were essentially different in their morphological and physiological-biochemical characteristics. In associations, cyanobacteria showed a higher (by tens of times) nitrogen-fixing activity compared to the monoculture and the morphological modifications of which were not observed in the monoculture (increase in cell size, increase in the portion of heterocysts among vegetative cells, appearance of the forms of unbalanced growth of cyanobacteria as giant, disc-shaped, curved, and rhomboid cells). At extremely low humidity (aw 0.50), associated cyanobacterial cells remained viable, whereas in the monoculture, chlorophyll decomposition and cells death occurred. The methods of high-resolution (H1 600 MHz) nuclear magnetic resonance (NMR) and pulsed-gradient spin echo NMR revealed a fraction of mobile protons in lyophilized samples of the cyanobacterium-actinomycete association, which was evidence of the presence of free water. This fraction was not found in the lyophilized samples of cyanobacterial and streptomycete monocultures. The revealed differences can explain the survival of cyanobacterial cells in associations.
Databáze: OpenAIRE
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