Streptococcus faecalis S-48 produces a broad spectrum antibiotic, active against Gram-positive and Gram-negative bacteria. This substance is produced in solid and liquid media and also in a defined basal medium. It is sensitive to protease, pronase, or trypsin, heating at 70 degrees C, and alkaline pH, but resistant to treatment with lipase, lysozyme, alkaline phosphatase, DNAase, RNAase, acidic or neutral pHs, and also lower temperatures (60 degrees C). Several organic solvents cause precipitation, but not inactivation. This antibiotic has been partially purified by gel filtration and further ion-exchange chromatography. Its molecular weight has been estimated close to 2000. The biological activity of this antagonistic substance against the selected indicator strains, Streptococcus faecalis S-47 and Escherichia coli U-9, is bactericidal. The characterization of this substance, initially classified as a bacteriocin, indicates that it is an antibiotic of peptidic nature. The significance of antibiotic occurrence in group D of the genus Streptococcus is also discussed.

1. Thyroidectomized rats injected daily with 0, 0.1, 2 or 25mug of l-thyroxine/100g body wt. were compared with intact controls. In plasma, the protein-bound iodine was decreased in the rats given the 0 or 0.1mug doses and increased in those given the 25mug dose. 2. Blood glucose decreased in those given 2mug and was augmented in those given 25mug, and ketone bodies were the same in all the groups. 3. Plasma insulin was lowest in the rats given the 0 or 0.1mug doses and was highest in those given the 2 or 25mug doses of thyroxine. 4. After 48h starvation, the decrease in blood glucose and increase in ketone bodies observed in all the groups was greatest in the group not supplemented with thyroxine. 5. Plasma insulin concentrations remained at the value for fed animals in the rats given the 25mug dose of thyroxine but decreased in the other groups. 6. In fed animals, concentrations of hepatic DNA P, citrate, total fatty acids and acetyl-CoA were similar in all the groups, and glycogen was low only in the rats given the 25mug dose of thyroxine. 7. After 48h starvation, liver DNA P, total fatty acids and acetyl-CoA increased in all the groups, except in the rats given the 25mug dose, where both total fatty acids and acetyl-CoA remained at the value for fed animals. Liver citrate did not change in the groups given the 0 or 25mug doses of thyroxine, but decreased in the other groups. 8. The results are discussed in relation to the regulation of intermediary metabolism in hypo- and hyper-thyroidism.

During the third part of pregnancy in the rat the concentrations of plasma insulin and tissue glycogen in the foetus increase progressively. These levels and the release of insulin by pancreas incubated in vitro were significantly higher than the values found in adult non-pregnant rats. After birth the correlation between plasma insulin concentration and the stores of glycogen was also evident. In the first day of life, the concentrations of plasma insulin, glycogen in liver, striated muscle and kidney decreased significantly; these values decrease even more during the first 15 days of lactation. After weaning started (20 days post partum), rapid increases of insulin and glycogen were observed, parallel to the slow growth of the newborn rat during the first 15 days of life and the more rapid rate of growth after 20 days. Similarly, the insulin content of the pancreas increased more significantly during the period in which pancreatic weight and plasma insulin concentrations increased more slowly. These results show that when plasma insulin concentrations increase, body growth and stores of glycogen are higher, suggesting an anabolic role of insulin in the foetal and newborn rat. 15, 30, 45, 60 and 90 min.The incubation medium, Krebs-Ringer bicarbonate buffer, was supplemented with glucose (0-6 mg/ml), gelatine (0-6 mg/ml), sodium fumarate, sodium glutamate and sodium pyruvate (5 mM). The incubations were done in a Dubnoff metabolic shaker at 37°C in a mixture of 02 and C02 (95 % : 5 %).

Studies of the hypothalamic-pituitary-thyroid axis have been performed in streptozotocin (STZ)-diabetic Wistar rats and their controls. Plasma PBI concentration, plasma and pituitary TSH, contents, and hypothalamic TRH content were measured by RIA in basal and stimulated conditions. Compared to controls, rats made diabetic by 6.0 or 7.5 mg STZ/100 g BW showed decreased plasma PBI and TSH and diminished pituitary TSH content, with greater alterations in rats receiving the highest STZ dose. Both diabetic groups showed an almost 50% reduction of hypothalamic TRH content in comparison with the mean control value. After thyroidectomy, pituitary TSH secretion increased in diabetic, ad libitum fed, and semistarved animals, but it was lower in the diabetic group in which the reduction in plasma PBI was similar or greater. To evaluate pituitary sensitivity to the inhibitory action of L-T4 on TSH secretion in diabetes, thyroidectomized control (Thx-C), thyroidectomized diabetic (Thx-D), and thyroidectomized semistarved (Thx-S) rats were injected twice daily for 7 days with either saline or a fractional L-T4 dose of 0.25, 0.50, or 1.00 microgram/100 microgram/100 g BW. In Thx-D rats, a daily dose of 1.00 microgram L-T4 was sufficient to normalize pituitary TSH secretion, while a dose of 2.00 microgram was required to induce a similar effect in the Thx-C and Thx-S animals. Pituitary TSH content was increased in the Thx-C group with increasing T4 doses. No modification in this parameter was seen in the Thx-D and Thx-S animals. The fact that diabetes caused a reduction in the hypothalamic TRH content indicates that the primary cause of pituitary-thyroid alterations in STZ-diabetic rats lies in the hypothalamus, although the metabolic imbalance induced by diabetes and, in less degree, by undernutrition could also be partly responsible for some of the described modifications.

Stable continuous-wave laser action in the near-infrared and in the green spectral region has been obtained in a self-frequency doubling solid-state laser, the Yb3+:MgO:LiNbO3 nonlinear crystal. By pumping with a Ti:sapphire laser and using a nearly concentric cavity, laser action at 1.06 μm was achieved with an absorbed power threshold of 101 mW and efficiency around 47%. As much as 60 mW of self-frequency-doubled radiation at 530 nm was also obtained with absorbed pump powers of 800 mW in critical cavity alignment. Efficient laser action was also obtained in the near-infrared region under pumping with diode laser.