Quantitation of a 55K cellular protein: similar amount and instability in normal and malignant mouse cells.

Quantitative expression of a specific 55,000 (55K)-molecular-weight cellular protein was studied in two groups of mouse embryo fibroblast (clonal) cells originating from two parent clones, one of which possessed high tumorigenicity and the other of which possessed very low tumorigenicity. From the clone with low tumorigenicity, tumor lines and clones were obtained by selecting rare spontaneously transformed highly tumorigenic (mutant) cells. Cells were labeled during exponential growth for 3 h at 37 degrees C, with [35S]methionine, and the cellular 55K protein was immunoprecipitated with a monoclonal antibody and quantitated. There were low and approximately equal amounts of 55K protein in cells (clones) with both low and high tumorigenicity from both groups of cells, and there was no correlation at all between quantitative expression of 55K protein and of cellular tumorigenicity. There was approximately 10- to 20-fold more 55K protein in all simian virus 40-transformed T antigen-positive derivative clones, as shown previously. The T antigen-negative revertant tumor lines and clones obtained by an immunological in vivo selection method had low amounts of 55K protein, similar to the parent cell before simian virus 40 transformation. In all of the T antigen-negative cells, including the highly tumorigenic cells, degradation (turnover?) of the 55K protein was rapid, and a half-life of 15 to 60 min was estimated from pulse-chase experiments. In all of the T antigen-positive cells the 55K protein was stable (half-life greater than 10 h). In primary cells established from the tumors induced by highly tumorigenic cells there was a very low or no detectable amount of the 55K protein. This is in contrast to the primary cells obtained from early murine embryos in which we have reported high amounts of (stable) 55K proteins.     

Growth of rural and urban children in the Valley of Oaxaca,Mexico

Weight, stature, arm circumference, and the triceps skinfold were measured in 1,410 school children, 6 through 14 years of age, from two urban colonias in the city of Oaxaca de Juarez (n = 479), and from two rural Ladino (n = 467) and two rural Zapotec (n = 464) communities in the Valley of Oaxaca in southern Mexico. Children from rural Ladino communities and urban colonias are significantly taller, heavier, and more muscular than children in rural Zapotec communities. The differences between rural Ladino and urban colonia children favor the former, particularly for weight and stature. These observations thus suggest (1) that children in the rural, indigenous communities in the Valley of Oaxaca are relatively undernourished compared to children in Ladinoized and urban communities, and (2) that rural-to-urban migration does not necessarily result in improved growth status.     

Growth of rural and urban children in the valley of Oaxaca,Mexico

Weight, stature, arm circumference, and the triceps skinfold were measured in 1,410 school children, 6 through 14 years of age, from two urban colonias in the city of Oaxaca de Juarez (n = 479), and from two rural Ladino (n = 467) and two rural Zapotec (n = 464) communities in the Valley of Oaxaca in southern Mexico. Children from rural Ladino communities and urban colonias are significantly taller, heavier, and more muscular than children in rural Zapotec communities. The differences between rural Ladino and urban colonia children favor the former, particularly for weight and stature. These observations thus suggest (1) that children in the rural, indigenous communities in the Valley of Oaxaca are relatively undernourished compared to children in Ladinoized and urban communities, and (2) that rural-to-urban migration does not necessarily result in improved growth status.     

Uptake and fate of bacteriophage phi W-14 DNA in competent Bacillus subtilis.

Phage phi W-14 DNA (in which one-half of the thymine residues are replaced by alpha-putrescinyl thymine) was taken up by competent Bacillus subtilis cells at a rate threefold higher than the rate of homologous DNA uptake. In contrast to other types of heterologous DNA, the amount of phi W-14 DNA taken up in 15 min exceeded the amount of homologous DNA taken up by a factor of two to three, as measured in terms of acid-precipitable material. The amount of phi W-14 DNA taken up was even greater than this analysis indicated if allowance was made for the fact that phi W-14 DNA was degraded more rapidly after uptake than homologous DNA. Competition experiments showed that the affinity of phi W-14 DNA for homologous DNA receptors was lower than the affinity of homologous DNA and was similar to the affinities of other types of heterologous DNA. The more rapid and more extensive uptake of phi W-14 DNA appeared to occur via receptors other than the receptors for homologous DNA, and these receptors (like those for homologous DNA) were an intrinsic property of competent cells. Uptake of phi W-14 DNA was affected by temperature, azide, EDTA, and chloramphenicol, as was uptake of homologous DNA. This was consistent with entry of both DNAs by means of active transport. After uptake, undegraded phi W-14 [3H]DNA was found in the cells in a single-stranded form, whereas a portion of the label was associated with recipient DNA, presumably as a result of incorporation of monomers resulting from degradation. Acetylation of the amino groups of the putrescine side chains in phi W-14 DNA decreased the affinity of this DNA for its receptors without affecting its ability to compete with homologous DNA.     

In vitro metabolism of C19 steroids in human endometrium

In order to quantitate the extent of intracellular metabolic conversions of C19 steroids in human endometrium, specimens of proliferative and secretory tissue were superfused at a constant rate with several pairs of labeled compounds at low concentrations. About 16% of dehydroepiandrosterone sulfate interacting with endometrial cells was converted to dehydroepiandrosterone and about 3% of this compound was converted to androstenedione. Androstenedione was reversibly reduced to testosterone and the extent of this conversion was shown to be several-fold higher in secretory than in proliferative tissue. About 1% of testosterone entering the cells was reduced to 5 alpha-dihydrotestosterone. These results demonstrate that the conversion of the main circulating C19 steroids in women, i.e. dehydroepiandrosterone sulfate and androstenedione, to 5 alpha-dihydrotestosterone, the compound considered to be the true intracellular androgen, is very small. In contrast, formation of testosterone from androstenedione is extensive and increases during the luteal phase under the influence of progesterone, a hormone known to stimulate the activity of 17 beta-hydroxysteroid dehydrogenase in human endometrium.     

Nitrofurantoin prompts the stringent response in Bacillus subtilis

Nitrofurantoin causes the stringent response in Bacillus subtilis. After exposure of a stringent strain to this drug, the intracellular concentrations of guanosine 3'-diphosphate 5'-diphosphate (ppGpp), guanosine 3'-diphosphate 5'-triphosphate (pppGpp) and ATP increased, while that of GTP decreased. In a relaxed strain no accumulation of ppGpp or pppGpp was observed, but both GTP and ATP declined after the addition of nitrofurantoin. Protein synthesis was equally sensitive to nitrofurantoin in both the stringent and relaxed strains, but the drug inhibited RNA accumulation only in the stringent strain, not in the relaxed strain. Nitrofurantoin also caused the accumulation of ppGpp in Escherichia coli and Serratia marcescens.     

Reactions between diglycolaldehyde dithioacetals and some nucleophiles

The homogeneous, neutral polysaccharide isolated from the crude polysaccharide of the fruit pulp from bael (Aegle marmelos) contains arabinose, galactose, and glucose in the molar ratios of 2:3:14. The linkages among the different monosaccharide residues were established through methylation analysis and Smith-degradation studies of the polysaccharide. The anomeric configurations of the different glycosyl groups were determined by study of the chromium trioxide oxidation of the acetylated polysaccharide. Results of these experiments have been discussed in order to assess the structure of the neutral polysaccharide.