[Trichothecene mycotoxins of Fusarium poae from different habitats].

Comparative study of the ability of three strains of Fusarium poae for the synthesis of trichothecen mycotoxins has been carried out. Studied strains were isolated from different habitats: forest soil, wheat (plant pathogen) and cranberry root (endophytic strain). All three strains were able to synthesize T-2 toxin, HT-2 toxin and T-2 tetraol but they were in various amounts. The soil strain 50660 was characterized by high level of synthesis of both HT-2 toxin and T-2 tetraol; plant pathogenic 50674 and endophytic 50685 strains were characterized by high level of T-2 tetraol synthesis and lower level of HT-2 toxin synthesis. The main trichothecene mycotoxin of this group - T-2 toxin - was detected in trace amounts for all three strains of F. poae.

[Characteristics of toxigenic properties of Myrothecium cinctum (Corda) sacc., 1886 and Myrothecium commune pidopl., 1969].

The comparative study of toxigenic potential of Myrothecium cinctum (12 strains) and Myrothecium commune (7 strains) was conducted. The ability to produce the complex of macrocyclic trichothecenes (MCTC) presented in ethanol soluble fraction (ESF), as well as fungistatic activity against yeasts test-cultures (strains Saccharomyces vini "Feodosia" and Candida stellatoidea 62) and rabbit skin test were evaluated. It was established that ESF output varied within wide limits in all studied strains of both species but it was significantly lower in M. commune strains. Higher ESF yields were accompanied as a rule by higher fungistatic activity and skin reaction in rabbits. The separate strains showed high biological activity with minor ESF output that could be possible caused by domination of more toxic components in complex preparation. The study of MCTC component structure by high performance liquid chromatography method (HPLC) showed with a few exceptions the presence of verrucarins A and J, roridins A, E, and H as well as unidentified components whose column retention times were 2.1 and 4.9 minutes. The production of roridin H and unknown component with 2.1 min. retention time was typical of M. cinctum strains while verrucarin A and unidentified component with 4.9 min. retention time was typical of M. commune strains.

[Biological activity of Penicillium sp. 10-51 exometabolites].

Silica gel column chromatography (silica gel "L" II kind of activity 100/160 mkm) of the chloroform extract from the cultural filtrate of Penicillium sp. 10-51 gave two fractions (chloroform and chloroform-acetone, 5:1) having biological activity. Recrystallization yielded two compounds. On the basis of physico-chemical and spectral data these compounds were identified as curvularin and hydroxycurvularin, which have a large spectrum of biological action as to bacteria, yeast, blue-green algae and phytopathogenic micromycetes.

[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.

[Mycotoxins: past, present and future]. / Mikotoksiny: proshloe, nastoiashchee, budushchee.

The paper deals with historical information concerning the investigation of mycotoxins and mycotoxicoses at the Institute of Microbiology and Virology of the NAS of Ukraine, main results of the works fulfilled for the last 25 years and possible trends of further investigations.