Further tests on the carcinogenicity of sorbic acid in the rat

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Cell wall composition of Hypomicrobium species

Chemical analysis of cell walls obtained from Hyphomicrobium B-522 and from a morphologically and nutritionally distinct organism, Hyphomicrobium neptunium (ATCC 15444), showed that the organisms have a similar cell wall composition, which is typical of gram-negative bacteria. The walls of both strains contained many amino acids, including the characteristic mucopeptide components diaminopimelic acid and muramic acid. Isolation of the mucopeptide by use of sodium dodecyl sulfate was successful only with cell walls of H. neptunium, thus revealing a difference between the walls of the two strains. The mucopeptide preparation contained glucosamine, muramic acid, alanine, glutamic acid, diaminopimelic acid, and glycine in molar ratios of 1.05:1.21:1.84:1.0:1.04:0.31, respectively. The concentration of glycine was sufficiently high to suggest that it is a mucopeptide component rather than an impurity.

Oral, subcutaneous and intratracheal administration of carcinogenic lactones and related substances: the intratracheal administration of cigarette tar in the rat

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Oestrogens in the blood of the cow

Extracts of jugular-vein blood of pregnant cows and of cows in oestrus were treated with methanolic HCl and phenolic fractions prepared. Assay by the mouse uterine-weight method failed to detect oestrogen in fractions from cows in oestrus or 2–3 months pregnant but indicated the presence of oestrogen, equivalent to about 1 μg. of oestrone/l. in blood from cows 5–6 months pregnant and about 7 μg./l. in blood from cows 7–9 months pregnant.

The activity of the phenolic fraction from blood of late pregnancy was shown to be due mainly to oestrone, most of which had been present in the blood as a water-soluble derivative.

Similar fractions from blood of cows in oestrus, assayed by the tetrazolium method of Martin, showed a total of 1–10 ng./l. (expressed as oestrone) activity being in the non-ketone and ketone fractions.

The activity of different fractions of homologous thyroid extract in the production of allergic thyroiditis in the rat

Rat thyroglobulin with a high degree of ultracentrifugal purity can be obtained by zone ultracentrifugation of crude thyroid extracts. The thyroglobulin fraction was even more effective than the original extract as an antigen for the production of experimental allergic thyroiditis. Material in the extracts with lower sedimentation coefficients than thyroglobulin were ineffective as antigens in this respect as was a homologous thyroid microsomal fraction.