[Microscopic fungi in chicken feed mixtures, their toxigenicity and toxicity for the chick embryo]. / Mikroskopické houby v krmných smesích pro kurata, jejich toxinogenita a toxicita pro kurecí embrya.

Contamination with microscopic fungi was studied in broiler complete feed mixtures in 1983-1984. The contamination levels ranged from 10(1) to 10(5) of fungus units per gram of feed (mostly around 10(3) units per gram). Sixty species of microscopic fungi of sixteen genera were isolated from the feeds. The genera Aspergillus and Penicillium occurred most frequently (97% of samples), followed by Mucor (93%), Cladosporium (79%), Rhizopus (52%) and Fusarium (41%). Of the 64 isolates of ten species of microscopic fungi, 42 (66%) were toxicogenic, and out of 49 such strains, 27 (55%) were toxic.

[Production of secalonic acid D by strains of Penicillium oxalicum and its toxic effects on chick embryos]. / Produkce sekalonové kyseliny D kmeny Penicillium oxalicum a její toxické úcinky na kurecí zárodek.

Over the years 1983 to 1984, eight strains of Penicillium oxalicum were isolated from feed mixtures for chickens; all of them produced on wheat secalonic acid D (1 to 22 mg X kg-1). As found out, toxic dose of secalonic acid D for two-day, three--day and four-day chicken embryos is 0.90, 2.80 and 3.80 micrograms, respectively. Teratogenic effects, microophthalmia and bilateral beak fissure was observed in the embryotoxicity range on all days of application.

Ovicidal fungi in soils of Cuba.

Thirty-six strains of ovicidal fungi were isolated from 122 investigated soil samples collected in Cuba. The isolated strains belong to 8 genera, 2 strains consist of sterile mycelium only. Most of the strains belong to the genus Fusarium (4 species, 1 undetermined strain), the remaining ones to Mortierella (3 species and 6 undetermined strains), Humicola (2 species), Paecilomyces (2 species) and Penicillium (2 species). The genera Verticillium, Gliocladium and Cunninghamella were represented by one species each. A majority of isolated strains exhibited a high to very high ovicidal activity immediately after isolation; strains with a lower initial activity occurred only exceptionally. The high ovicidal activity has been preserved till now in the following five strains: Paecilomyces marquandii (2 strains), Fusarium solani f. spec. radicicola (1 strain), Mortierella sp. (1 strain) and the sterile mycelium (1 strain).

Production of beta-glucosidase, exo-beta-1,4-glucanase and endo-beta-1,4-glucanase by selected microscopic fungi.

Production of beta-glucosidase, exo-beta-1,4-glucanase and endo-beta-1,4-glucanase was screened in 58 species of imperfect fungi, mucoral fungi and some ascomycetes. beta-Glucosidase activity was found in all of the tested microorganisms, exo-beta-1,4-glucanase activity in 23, and endo-beta-1,4=glucanase activity in 38 microorganisms. Growth on cellobiose was found in all tested microorganisms, growth on carboxymethylcellulose in in 38 tested strains.

Production of alpha-amylase by microscopic fungi.

The amylolytic activity and especially the production of alpha-amylase (EC 3.2.1.1) and alpha-glucosidase (EC 3.2.1.20) was screened in imperfect fungi, mucoral fungi and some ascomycetes. The character of the polysaccharide system, which is responsible for the utilization of alpha (1 to 4) glucan, was specified with a concomitant screening of growth on soluble starch. The amylolytic activity was found in 29 strains out of the 49 tested.

[Isolation of A. boydii from the soil of the Tadzhik SSR]. / Vydelenie A. boydii iz pochvy v Tadzhikskoi SSR

The authors present a detailed description of a pathogenic strain of Allescheria boydii Shear, isolated from a soil sample obtained from the karst cave in the vicinity of the Iskan derkerev lake, the Tajik SSR (the morphology of the conidial and ascosporic stages of the fungus, its physiological and biochemical activity and experimental pathogenicity). Data on the existence of this causative agent as a saprophyte in the soil of various continents are also given. A conclusion was drawn that A. boydii was an unpretencious geophilic fungus readily adaptible to the environmental conditions, much more widespread in nature than believed formerly.