[Use of cyanobacteria for indication of toxic action of stachybotrys toxins]. / Vikorystannia tsianobakterii dlia indykatsiï toksychnoï diï stakhibotriotoksyniv.

Screening of cyanobacteria cultures for their sensitivity to the action of complex preparations of toxins from 18 strains of Stachybotrys chartarum has been carried out with the purpose to search for new test-organisms to create a reliable system of biotesting of stachibotryotoxines. In contrast to other cultures of unicell (Anacystis nidulans) and filamentous (Anabaena sp., Anabaena variabilis, Nostoc linckia, Plectonema boryanum) cyanobacteria used in the experiment, only one culture of unicell cyanobacterium Synechococcus cedrorum proved to be highly sensitive to the action of preparations of the whole group of studied mycotoxins. Their activity with respect to this culture varied within wide limits (lysis zone diameter is 11-30 mm) and for the most of strains it coincided with or exceeded this index determined with the use of other biotests. Owing to the use of Synechococcus cedrorum as test culture the authors have proved for the first time the toxicity of three strains of Stachybotrys chartarum (K15822, 14722, 14186). Basing on the data obtained the authors have determined the culture of the unicell cyanobacterium, according to the sign of high sensitivity to all the studied stachibotryotoxin preparations of solid and liquid nutrient media, as a new test-organism for detection of this group of toxins and it may be recommended for practical use. Optimal conditions for growing test-culture and biotesting of toxins have been defined.

[Antibiotic properties of the Pseudoalteromonas genus bacteria isolated from the Black Sea water and molluscs]. / Antybiotychni vlastyvosti bakterii rodu Pseudoalteromonas, vydilenykh z vody ta moliuskiv Chornoho moria.

Antagonistic properties of 41 strains of Alteromonas-like bacteria isolated from the Black Sea water and molluscs have been studied. Being grown on the rich medium "B" for marine bacteria, 21% of strains have shown high antagonistic activity against phytopathogenic fungi; 6% of strains inhibited the growth of Bacillus subtilis, Proteus vulgaris and Candida albicans. Spectrum of antagonistic activity was essentially changed on synthetic "BM" medium with acetate, glutamate, alpha-alanine as a single source of carbon and was directed against Pseudomonas aeruginosa. Culture liquids and acetone extracts of microbial biomass of 34% of the studied strains have shown activity against bacteria, fungi and cyanobacteria. Strains producing the wide spectrum of antimicrobial substances (Alteromonas macleodii, Pseudoalteromonas citrea, P. haloplanktis, P. aurantia, Pseudoalteromonas sp.), fungicidal and algocidal substances have been found. Both extra- and intracellular metabolities of marine bacteria (including the pigments) were active.

[Comparative characteristics of physico-chemical and regulating properties of aspartate kinases from three species of cyanobacteria]. / Porivnial'na kharakterystyka fizyko-khimichnykh ta rehuliatornykh vlastyvostei aspartatkinazy tr'okh vydiv tsianobakterii.

Aspartokinases have been isolated from the cell-free extracts of Plectonema boryanum, Anabaena variabilis and Synechococcus cedrorum. Their physico-chemical characteristics and peculiarities of retroregulation by amino acids were studied. It has been shown that in P. boryanum cells aspartokinase reaction is catalyzed by only one enzyme, which is similar to the previously described bacterial origin enzymes. Three izoenzymes, which differ in their main properties and amino acids-effectors, have been founded in the cells of A. variabilis. One enzyme with aspartokinase activity, which differs from other cyanobacteria enzymes in some physico-chemical features has been founded in the cells of S. cedrorum.