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Biomedical subjects

G H Nelson

Publications and source records attributed to G H Nelson.

At least 109 records · Page 6Linked to original sources
PubMed1967

Estrogenic metabolite produced by Fusarium graminearum in stored corn.

A derivative of resorcinylic acid, produced by the fungus Fusarium graminearum, has been found to be responsible for the estrogenic signs in swine and laboratory rats. An estrogenic response in rats can be incited by injecting intramuscularly as little as 20 mug of the estrogen (F-2). Stimulation in growth of rats was noted at the lower concentrations (20 to 40 mug) of a series. Up to 3,500 ppm of the estrogen was produced on a solid corn medium. The compound is relatively stable to heat and ultraviolet irradiation. Methods of analysis have been developed and include: extraction procedures, evaluations by ultraviolet absorption spectrophotometry, thin-layer chromatography, and gas-liquid chromatography.

Animals↗
PubMed1967

Microflora of black and red pepper.

Dilution cultures of 30 samples of ground black pepper yielded an average of 39,000 colonies of fungi per g, with a range of 1,700 to 310,000 per g. Total numbers of colonies of bacteria from 11 samples averaged 194,000,000 per g, with a range from 8,300,000 to 704,000,000 per g. A variety of fungi grew from nearly all surface-disinfected whole peppercorns that were cultured. Thirteen samples of ground red pepper from the United States yielded an average of 1,600 colonies of storage fungi per g and an equal number of other fungi; five samples from India yielded an average of 78,900 colonies of storage fungi per g and 169,400 colonies of other fungi per g. Among the fungi from both black and red pepper were Aspergillus flavus and A. ochraceus, some isolates of which, when grown for 8 to 10 days on moist autoclaved corn and fed to white rats or to 2-day-old Pekin ducklings, were rapidly lethal to them. Aflatoxin B(1) was isolated from one of the samples of corn on which A. flavus from black pepper was grown. Among the bacteria isolated from ground black pepper were Escherichia coli, E. freudii, Serratia sp., Klebsiella sp., Bacillus sp., Staphylococcus sp., and Streptococcus sp. No cultures of Shigella or Salmonella were found.

Aflatoxins↗