Thermoinductive Regulation of Gibberellin Metabolism in Thlaspi arvense L. (II. Cold Induction of Enzymes in Gibberellin Biosynthesis).

Vernalization of Thlaspi arvense L. results in the alteration of gibberellin (GA) metabolism such that the metabolism and turnover of the GA precursor ent-kaur-16-en-19-oic acid (kaurenoic acid) is dramatically increased. This cold-induced change in GA metabolism is restricted to the shoot tip, the site of perception of cold in this species (J.

The physiological significance of phenylacetic Acid in abscising cotton cotyledons.

The physiological role of phenylacetic acid (PAA) as an endogenous regulator of cotyledon abscission was examined using cotton (Gossypium hirsutum L. cv LG 102) seedlings. Application of 100 micromolar or more PAA to leafless cotyledon abscission-zone explants resulted in the retardation of petiole abscission and a decrease in the rise of ethylene evolution that normally accompanies aging of these explants in vitro.

The isolation and identification of 14C-sulfamethazine (4-amino-n-(4,6-dimethyl-2-pyrimidinyl)[14C]benzenesulfonamide) metabolites in the tissues and excreta of swine.

Pigs were given a single oral dose of 14C-sulfamethazine (4-amino-N(I4,6-dimethyl-2-pyrimidinyl)[14C]benzenesulfonamide). Approximately 78% of the 14C was eliminated in the urine and 18% was eliminated in the feces within 192 hr after dosing. The percentage of the 14C remaining in the animals after dosing was as follows: 6 hr, 88%; 24 hr, 49%; 48 hr, 14%; 192 hr, less than 1%.

Carbon-14-labeled diethylstilbestrol synthesis by the McMurry method: concurrent formation of hexestrol.

Isotopically labeled diethylstilbestrol prepared from p-methoxypropiophenone by coupling with TiCl3-LiA1H4 contained approximately 50% hexestrol. Nonlabeled preparations and a subsequent labeled preparation had less than 2% hexestrol in them. Initial examinations for purity by gas-liquid chromatography, thin-layer chromatography, and isotope dilution did not show the presence of hexestrol.