Lack of correlation between loss of anchorage-independent growth and levels of transformation-specific p53 protein in retinoic acid-treated F9 embryonal carcinoma cells

It has been shown that differentiated derivatives of retinoic acid (RA)-treated F9 embryonal carcinoma cells become non-malignant. In the present study it is asked whether this loss of malignancy is due to cellular differentiation. Because the ability of cells to grow in suspension correlates with in vivo tumorigenicity, we determined the time course of the loss of this property, after RA treatment, with relation to the differentiation to parietal endoderm and the acquisition of normalcy in several common transformation-specific properties of F9 cells. Our results show that pretreatment with RA for 24 h caused 80% inhibition of anchorage-independent growth in F9 cells, and this inhibition reached its highest level (98%) after pretreatment with RA for 48 h and longer. However, all other observed transformation-related properties, and the levels of plasminogen activator (marker for parietal endoderm) remained unaltered at this early post-treatment stage. These observations suggest that the loss of malignancy is a relatively early event in the biochemical pathways involved in the RA-induced differentiation of F9 cells. Furthermore, our data show that the presence of elevated levels of p53 alone may not be sufficient to maintain the anchorage-independent growth and the rapid proliferation of F9 cells.     

Metabolism of steroid acetates by Streptomyces albus

Fermentation of 16-dehydropregnenolone acetate (1a) with Streptomyces albus yielded 16-dehydropregnenolone (1b) and 16-dehydroprogesterone (IIa). Similar incubation of pregnenolone acetate (Ic) with the strain afforded pregnenolone (Id), progesterone (IIb) and 20 alpha-hydroxy progesterone (IIc) while dehydroepiandrosterone acetate (IIIa) under the conditions was converted to dehydroepiandrosterone (IIIb), androstenedione (IVa) and testosterone (IVc). The strain was also capable of converting testosterone acetate (IVb) having the 17-acetoxy function in the 5-membered D-ring to testosterone (IVc) and androstenedione (IVa). All the products were identified by the application of various chemical and spectrometric techniques.     

Steroids and related products. LIV. The synthesis of 11-oxa steroids. VI. The synthesis of 11-oxatestosterone

The synthesis of 11-oxatestosterone from 11-oxa-5 alpha-androstane-3,17-dione, which is available from hecogenin, is described. The product shows, in comparison with the natural hormone, diminished androgenic and anabolic activities.     

Hydrogen peroxide formation and lipid peroxidation in rat uterus—effect of hormones and vitamin E

The effect of estradiol-17β and progesterone given separately as well as in combination on the rate of hydrogen peroxide formation and lipid peroxidation in the uteri of ovariectomized rats was studied. Estradiol in 3μg dose per day per animal elicited maximum stimulatory response and progesterone (100μg), on the other hand, was without any such effect. However, progesterone given along with estradiol completely prevented the effect due to the latter. In the same way, vitamin E, a well known antioxidant was found to be extremelv effective in protecting the uterus from the highly peroxidative action of estradiol-17β.     

Studies on the partial structure of the O-antigen of Vibrio cholera Ogawa G-2102

Detailed information was obtained regarding the partial structure of the lipopolysaccharide (LPS), containing glucose, glucuronic acid, 2-amino-2-deoxy-glucose, L-glycero-D-gluco-heptose, and small proportions of L-glycero-D-manno-heptose, mannose, and galactose, isolated from Vibrio cholera Ogawa G-2102. Structures of three oligosaccharides were determined. Results of deamination experiments established the sequence of the linkages between the amino sugar and heptose residues in the O-antigenic polysaccharide.     

Studies on Flowering Responses of Urena lobata

Urena lobata L. is a qualitative short-day plant with a critical dark period of about 12 hr. A minimum of 12 short days are required for floral initiation. Gibberellic acid (GA₃) sprayed onto the leaves promoted flowering. The growth retardant, (2-chloroethyl)-trimethylammonium chloride (CCC) markedly inhibited flowering and stem elongation. This inhibition was reversed by subsequent application of GA₃.     

The influence of dietary protein on ascorbic acid metabolism in rats

1. d-Glucuronolactone reductase, l-gulonolactone oxidase, uronolactonase, dehydroascorbatase, l-gulonate dehydrogenase and l-gulonate decarboxylase have been measured in the tissues of rats fed on diets containing variable amounts of protein. Rats fed on a protein-free or a 2% casein diet for 15 days showed a marked decline in the activities of d-glucuronolactone reductase, l-gulonolactone oxidase, uronolactonase and dehydroascorbatase in the liver, and no change in l-gulonate dehydrogenase and l-gulonate decarboxylase activities in the kidney when compared with rats fed on diets containing 9%, 18% or 25% casein. Giving diets containing 60% or 88% casein to rats did not appreciably alter the activities of uronolactonase, dehydroascorbatase, l-gulonate dehydrogenase and l-gulonate decarboxylase, but inhibited considerably the activities of d-glucuronolactone reductase and l-gulonolactone oxidase in the liver, resulting in decreased synthesis of ascorbic acid. 2. Rats fed on a 25% casein diet showed maximal weight gain, higher tissue reserve of ascorbic acid and higher urinary excretion of both ascorbic acid and glucuronic acid when compared with rats fed on diets containing lower or higher amounts of protein.