Biochemical changes in liver due to aflatoxin.

The effect of a single dose of aflatoxin on the content of glycogen, lipid and protein of mouse liver was studied 2 hr after injection of the toxin but no significant change was observed. Enzymes in liver of mice were assayed 2 hr and 8 hr after aflatoxin treatment. In general, the enzymes of particulate fraction and isocitrate dehydrogenase in the supernatant showed a significant increase; the remaining enzymes of the supernatant fraction decreased at both time intervals.

Morphogenesis and fine structure of Leucothrix mucor and effects of calcium deficiency.

Phenotypic expressions of morphogenesis and fine structure of Leucothrix mucor were determined when the organism was grown with and without added CaCl(2) in a synthetic seawater medium. Evidence is presented to show that a bulb can form in the absence of a knot formation and that a bulb may give rise to a "germ-tube." In comparison with normal cells, which show transverse septa at right angles to the axis in dividing cells, the bulbs exhibited transverse septa at odd angles, which may explain the mechanism of bulb formation.

Effect of enterotoxin B on human volunteers.

A dosage of 20 to 25 mug of pure enterotoxin B can produce clinical manifestations of enterotoxemia in man, who seems to be more sensitive than monkey.

Radiorespirometric studies of Leucothrix mucor.

Catabolic capabilities of Leucothrix mucor were studied by radiorespirometric technique with a liquid scintillation spectrometer. Through measurement of relative rates and total percentages of (14)CO(2) produced, together with the determination of the cellular incorporation of (14)C from different carbon atoms of various labeled substrates, such as simple carbohydrates, intermediary metabolites, and amino acids, the essential characteristics of the primary and secondary pathways operative in this organism were examined. These substrates appeared to be degraded mainly via enzymes of the Entner-Doudoroff pathway in conjunction with the tricarboxylic acid cycle.

Enrichment medium for selection of Salmonella from fish homogenate.

A new liquid medium, called "dulcitol selenite enrichment," has been developed for the detection and enumeration of Salmonella in foods. The medium is not only highly selective in enriching Salmonella and inhibiting completely or appreciably other extraneous organisms commonly found in seafoods, but is also highly sensitive in recovering as low as 2 to 7 cells of Salmonella, even in the presence of large numbers (10(4) to 10(6) cells) of mixed flora common to these foods. The addition of seafood material does not seem to interfere with the sensitivity, selectivity, or productivity of the medium.

Detection and enumeration of fecal indicator organisms in frozen sea foods. II. Enterococci.

Consistently high recoveries of enterococci as compared to the low numbers of coliforms obtained from the same samples of frozen sea foods are indirect evidence that enterococci are better indicators of contamination in such foods. The use of azide dextrose broth, modified by the incorporation of bromthymol blue, and of ethyl violet azide broth as presumptive and confirmation tests, respectively, were found to be highly specific for the detection and enumeration of enterococci in these samples. Tetrazolium agar medium, when used as a third step after the confirmation test, provides a reliable differentiation of Streplococcus faecalis types from other group D streptococci.