[Study of specificity of fungistatic effect of trichothecene mycotoxins].

In attempt to realize the purposeful search of highly sensitive and highly specific microbial test-cultures the authors studied the ratio between selected before species of yeast to the wide set of different mycotoxins including macrocyclic trichothecenes (T-2 toxin, HT-2 toxin, T-2 triol, T-2 tetraol, NT-1 toxin, NT-2 toxin, fusarenon-X, diacetoxyscirpenol, deoxynivalenol, trichothecin, trichothecolon, neosolaniol, verrucarin A, roridin A, roridin H, aflatoxins, B1, B2, G1 and G2, sterigmatocystin, patulin, fusaric acid, ochratoxin A, zearalenon and their derivatives). It was supposed to define borders of specific sensitivity of test-cultures. The value of minimal inhibiting concentration (MIC) of mycotoxins, which caused fungicide action in respect of the investigated yeast strains, was used as the estimation criterion. Extremely few species with narrow specific sensitivity to individual trichothecenes were found. Strains with group sensitivity to investigated trichothecene mycotoxins (MCTC) were more widely presented. Selectivity in respect of either simple (T-2 toxin), or MCTC (verrucarin A, roridin A, roridin H) is traced for some species. Taxons with mixed selectivity were discovered. Exceptionally high fungistatic activity was characteristic of the investigated MCTC, T-2 toxin, trichothecin. Values of MCTC for these substances in respect of more sensitive strains varied in the borders of 0.03-0.1; 0.1-1.0 and 0.02-0.1 mcg/disk, correspondingly. It was less expressed for diacetoxyscirpenol, deoxynivalenol, trichothecolon (0.8-5.0; 0.1-2.0 and 0.8-4.0 mcg/disk, correspondingly). The data obtained give reasons for completing the bank of yeast test-cultures with wide potentialities of mycotoxins indication in various food and fodder substrates.

[Characteristic of the yeast isolated from patients with leukaemia].

It has been shown that biotopes of upper respiratory system and intestine were contaminated with yeast in 44.6% of patients with leukaemia (of 112 examined ones). Their quantity exceeds the boundary value for practically healthy people and is > or = 10(2) KOE/ml in the nasal activity and fauces and < or = 10(4) KOE/g in the intestine. It was established that in patients with leucemia the mycotic complications are mainly caused by anamorphous yeast of ascomycetic affinity. Candida albicans, as well as C. glabrata, C. rugosa and Candida sp. play the leading role. The Candida genus species are mainly sensitive to amphotericine B, clotrisamol and nistatin.

[Search for lectin producers among the yeast of Pichia Hansen emend. Kurtzman genus]. / Poisk produtsentov lektinov sredi drozhzhei roda Pichia Hansen emend. Kurtzman.

Strains (103) of yeast from Pichia genus: P. anomala, P. guilliermondii and P. membranaefaciens species have been investigated. The researchers have found 87 strains (84.5%) capable to form extracellular and surface lectins with activity to 512 hemagglutinating units. The overwhelming number of strains (75.7-92.6%) synthesized lectins of the both forms. Considerably less quantity of lectin producers of some form--extracellular or surface ones--have been found. Availability of producers of extracellular lectins was characteristic to greater extent of the yeast of P. anomala and P. guilliermondii, and producers of surface lectins--mainly of P. guilliermondii. The most active producers of lectins have been isolated from human and animal organisms, soils and wine.

[On the identity of Candida utilis and Pichia jadinii yeast species]. / Ob identichnosti vidov drozhzhei Candida utilis i Pichia jadinii.

Life cycles of Candida utilis (Henneberg) Lodder et Kreger-van Rij imperfect yeast (13 strains) used in industry were the study subject. When the strains were mated, we detected one of the stages of sexual process--conjugation of cells of the opposite mating type. Most of the studied cultures conjugated on the 2d-3d day. No ascospores were formed. Haploidy and heterothallism of the studied C. utilis strains were confirmed by hybridization of auxotrophic mutants. Based on PCR assay results, the yeasts are demonstrated to belong to the ascospore perfect yeast species of Pichia jadinii (A. et R. Sartory. We ill et Meyer, Wickerham) Kurtzman.

[Biological deacidification of wines using lactic-acid bacteria and yeasts]. / Biologicheskoe ponizhenie kislotnosti vin s pomoshch'iu molochnokislykh bakterii i drozhzhei.

Based on a study of 200 lactic-acid bacteria monocultures and 30 associating lactic bacteria and yeasts cultures, a stable association was created formed by Leuconostoc oenos, Pediococcus pentosaceus and Saccharomyces cerevisiae yeasts, intended for the biological deacidification of wine. Physiology of microorganisms and their effect on the wine chemical composition was studied. By means of selective association, high quality fine wines were produced from the high-acid wines.

[Search for lectin producers among some yeast species]. / Poisk produtsentov lektinov sredi nekotorykh vidov drozhzhei.

Hemagglutinating properties of culture liquid and cells of 142 yeast strains of species Saccharomyces cerevisiae, Kluyveromyces marxianus, K. dobzhanskii, K. lactis var. lactis and K. lactis var. drosophilarum, isolated from various sources have been studied. A capacity of yeast (44% of the studied strains) to synthesize both lectins bound to a cell and extracellular lectins has been established; the latter have been found in yeast for the first time.

[Screening of alpha-N-acetylgalactosaminidase producers among microorganisms of different taxonomic groups]. / Skrining produtsentof al'fa-N-atsetilgalaktozaminidazy sredi mikroorganizmov razlichnykh taksonomicheskikh grupp.

Screening of producers of alpha-N-acetylgalactosaminidase among 854 strains of micromycetes, 171 yeast and 357 bacterial cultures has been carried out. A capacity to synthesize the enzyme was revealed in 11% of cultures. Representatives of Aspergillus genus (activity--0.11-0.142 un./ml) were most active in producing the enzyme. It has been established that glucosidases spectrum in the culture liquid of 18 most active strains was characterized by complete homogeneity and by the presence of a rather high level (0.5-0.9 un./ml) of alpha-galactosidase activity. Complex preparations of alpha-N-acetylgalactosaminidase and alpha-galactosidase have been obtained from the culture liquid of producers by fractionation by ammonium sulphate (30 and 90% saturation); their pH- and thermo-optimum, pH- and thermal stability have been studied. It was shown possibility to induce alpha-N-acetylgalactosaminidase synthesis by a number of carbohydrates (galactose, glucose, galactosamine, and glucosamine), complex-forming substances (guanidine HCl), nitroaminoguanidin and guanidine carbonate and bovine blood. As a result the strain of Aspergillus niger 185 III was chosen which activity level could be increased more than 3 times (activity--0.6 un./ml as compared to initial one).

[The yeast flora of blood-sucking mosquitoes]. / Drozhzhevaia flora krovososushchikh komarov.

Yeast flora composition has been studied in natural populations of blood-sucking mosquitoes of genera Aedes. Anopheles and Culex dwelling in the territory of Ukraine. The authors have distinguished 18 yeast species belonging to 7 genera. Species Candida famata, C. (Yarrowia) lipolytica as well as the yeast of genera Rhodotorula and Cryptococcus dominate on the larvae and imago of mosquitoes. The distinguished strains are the components of normal microflora of blood-sucking mosquitoes and take no pathogenic effect on the laboratory culture of mosquitoes Aedes aegypti.

[Yeasts contaminating salmon roe]. / Drozhzhi, kontaminiruiushchie ikru lososia.

Quantitative and species compositions of yeast contaminating eggs, fry and fingerlings of Salmo gairdneri Rich under artificial breeding have been studied. Prevalence of species of genera Candida, Rhodotorula, Cryptococcus and Debaryomyces is noted. Yeast isolated from perished eggs and sick fry do not possess pathogenic properties. Certain strains of yeast make stimulating effect on the studied microorganisms.

[The intestinal microflora of persons subjected to a radiation lesion]. / Kishechnaia mikroflora liudei, podvergshikhsia radiatsionnomu porazheniiu.

The content of large intestine has been studied in persons exposed to radiation injury in consequence of the accident at the Chernobyl Atomic Power Plant. It is stated that bifidobacteria (10(7)-10(10) cells in 1 g of feces) prevailed (as in healthy people), Bifidobacterium indicum being a dominating species. Amount of lactic-acid bacteria in 1 g of defecations of examined patients was within the range of 10(6)-10(9) cells and in certain persons it reached 10(10) cells (primarily fecal Enterococci). A considerable amount of patients with acute radiation sickness of the 3d degree had in their intestine 10(9)/g of lactic-acid bacteria, Lactobacillus casei and L. plantarum prevailing there. The frequency of yeast isolation from defecations of patients constituted 83%, while the number of cells in 1 g of feces--from 10 to 10(4). Yeast of the Candida genus, mainly Candida parapsilosis, prevailed. The species composition of isolated microorganisms has no substantial differences from microcenosis of healthy people. The content of intestine of persons suffered from radiation is characterized only by greater amount of lactic-acid bacteria and enterococci as compared with healthy adults.

[The antibiotic properties of macrocyclic trichothecene mycotoxins]. / Antibioticheskie svoistva nekotorykh makrotsiklicheskikh trikhotstsenovykh mikotoksinov.

Some trichotecenic mycotoxins (verrucarine A, roridines A and H, T-2-toxin) have been studied for their antibiotic effect on a wide spectrum of the yeast cultures (761 strains). The studied substances differ both in their activity and the action character. The yeast strains promising for development of microbiological methods of indication and detoxification of mycotoxins have been revealed.

[The effect of Pichia guilliermondii yeasts on the body of laboratory animals]. / Vliianie drozhzhei Pichia guilliermondii na organizm laboratornykh zhivotnykh.

Conditionally pathogenic species Pichia guilliermondii which, being parenterally introduced to white mice, induced pathological changes in viscera and rarely death, has been revealed among species of genus Pichia previously considered as a nonpathogenic genus. The strains differ considerably between themselves in virulence. The latter does not depend on the yeast sex and the source of strain isolation.

[Yeast antagonists in the normal microflora of the intestinal tract in the long-lived inhabitants of Abkhazia]. / Drozhzhi-antagonisty v normal'noi mikroflore kishechnogo trakta dolgozhitelei Abkhazii.

Yeast of different taxonomic groups isolated from the organism of long-livers of Abkhazia have been studied for their antagonistic activity relative to the conditionally pathogenic and pathogenic bacteria and for the presence of the killer factor. It is shown that representatives of ten species of fungi are antagonists of the studied bacteria, the strains of Saccharomyces cerevisiae being the most active antagonists. The presence of the killer factor is found in representatives of five species o the yeast. It is supposed that the antagonistic activity relative to the bacteria and the killer activity in the yeast are due to substances of different chemical nature.