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Biomedical subjects

J Reiss

Publications and source records attributed to J Reiss.

At least 109 records · Page 6Linked to original sources
PubMed1983

Influence of Fusarium and Myrothecium mycotoxins on dehydrogenase activity of Saccharomyces cerevisiae.

The Fusarium and Myrothecium mycotoxins roridin A, diacetoxyscirpenol, verrucarin A, T-2 toxin and zearalenone (10(-2) and 10(-3) mg/ml) inhibit the unspecific dehydrogenase activity of baker's yeast (Saccharomyces cerevisiae) in vivo. The action of these toxins is in the same order as that of aflatoxin B1. It is suggested that at least the trichothecenes decrease the dehydrogenase activity by an interaction with thiol groups of the active center of the enzymes.

Fusarium↗
PubMed1983

Antigenic hemagglutination inhibition test in examining of the culture supernatants of Clostridium botulinum types A, B, E, and F and some related bacterial species.

The hemagglutination inhibition test with using lyophilized preparations of the double botulinal indicator system (antigen sensitized erythrocytes and type-specific homologous antitoxic globulin) was used to the identification of the Cl. botulinum types A, B, E and F culture supernatants and the supernatants of other related bacteria. In the examined indicator hemagglutination system, the type-specific results were obtained in spite of the existence of antigenic cross-reactivity known inside the genus Clostridium. Absence hemagglutination inhibition reaction of the botulinal indicator system with cultured supernatants of the protein A - positive Staph. aureus strains was discussed.

Antigens, Bacterial↗
PubMed1982

Development of Aspergillus parasiticus and formation of aflatoxin B1 under the influence of conidiogenesis affecting compounds.

The influence of various inhibitors of hyphal growth, sporulation and biosynthesis of aflatoxin B1 in Aspergillus parasiticus NRRL2999 was studied. 6-Thioguanine, DL-ethionine, fluoroacetic acid and phenylboric acid, inhibitors of maturation of fungal conidiophores and of conidiogenesis, were added at various concentrations to malt extract agar. Lower concentrations of 6-thioguanine and DL-ethionine did not inhibit the growth of hyphae and the sporulation. Phenylboric acid reduced conidiogenesis more than hyphal growth. The yields of aflatoxin B1 were significantly reduced. Additions of fluoroacetic acid did not greatly affect the growth of hyphae but totally inhibited the production of conidia and concurrently significantly reduced the formation of aflatoxin B1. An interrelation between conidiogenesis and onset of secondary metabolism in A. parasiticus is evident.

Aflatoxin B1↗
PubMed1982

Comparison of the ability of three Aspergillus strains to form aflatoxins on bakery products and on nutrient agar.

The growth of Aspergillus parasiticus NRRL 2999, A. parasiticus NRRL 3000 and A. flavus NRRL 3251 on whole wheat bread and on cake ('Rührkuchen') was compared and the formation of the aflatoxin B1, B2, G1, G2 and M2 on these substrates and, for purpose of comparison, on malt extract agar was determined. On cake the moulds grew better than on bread and formed the highest yields of aflatoxins. Malt extract agar was the most unfavourable substrate for toxin production. The ratio M1/B1 on bread and cake was in the order of 0.1-0.4 and was higher than the data reported for grains. The highest yields of aflatoxin B1 (1.0 micrograms/g) were produced by A. flavus NRRL 3251 on cake.

Aflatoxin B1↗
PubMed1981

Studies on the formation of aflatoxin M1 in bakery products. Mycotoxins in foodstuffs. XIII.

The aflatoxinogenic moulds Aspergillus flavus NRRL 3251, A.parasiticus CMI 89717 and A.parasiticus NRRL 2999 are able to grow on various types of bread, yet, only the last fungus can produce aflatoxin M1 on these substrates. The highest yields (4 micrograms/kg) of the toxin were found on whole wheat bread at a "Säuregrad" (total acid content) of 5-6 and at an incubation temperature of 30 degrees C. The toxin levels decreased with increasing time of growth; this was probably due to a further metabolism of aflatoxin M1. A.flavus NRRL 3251 and A.parasiticus CMI 89717 grew better and produced more toxin on cake ("Rührkuchen") with aw 0.92 than on cake with lower water activity.

Aflatoxin M1↗
PubMed1981

Determination of botulinum toxin type by the reaction of indirect hemagglutination inhibition.

Results of investigations are reported which confirm the possibility of in vitro serological determination of the types of botulinus toxins and tracing the antigen mosaic of the preparations containing mixtures of soluble antigens of these toxins. This possibility has been opened by an appropriate combination in the arrangement of the reaction of inhibition of the antigenic indirect hemagglutination.

Antigens, Bacterial↗
PubMed1978

Mycotoxins in foodstuffs. XII. The influence of the water activity (a-w) of cakes on the growth of moulds and the formation of mycotoxins.

The influence of various a-w values (high, moderate and low, e.g. 0.92, 0.87, and 0.82) of cakes ("Rührkuchen", made of wheat flour, sugar, eggs, fat and water) on the development and the mycotoxin production of Aspergillus flavus (aflatoxins), A. versicolor (sterigmatocystin), A. ochraceus (ochratoxin A), Penicillium chrysogenum (citrinin) and P. expansum (patulin) was investigated. None of the moulds was able to germinate at an a-w of 0.82. An increase of the water activity resulted in a pronounced growth of the five fungi. Citrinin was not formed on the cakes at all. The yields of the other mycotoxins were not markedly influenced by the a-w (0.92 or 0.87). During the development of the moulds the a-w of the substrate was lowered at first (water requirement during germination and initial growth) and subsequently increased (initiation of the secondary metabolism).

Aspergillus↗
PubMed1978

[The biochemical activity of the aflatoxins (author's transl)].

Results of experiments with the Salmonella typhimurium-liver microsome technique make it evident that the mutagenic and carcinogenic metabolite of aflatoxin B1 is aflatoxin B1-2,3-oxide. This compound forms adducts with guanine in DNA. There is a close relationship between the mutagenic activity and the hepatocarcinogenic property of the different aflatoxin derivatives.

Aflatoxins↗