Prostatic steroid-binding protein. Isolation and characterization of C3 genes

Prostatic steroid-binding protein, whose expression is stimulated by androgens, consists of two subunits, one containing the polypeptides C1 and C3 and the other containing the polypeptides C2 and C3. We have isolated and sequenced cDNA clones specific for C3 mRNA and used them to isolate and characterize genomic clones for two C3 genes. Both genes are 3.2 kilobases with identical exon/intron arrangements, which is similar to the organization of the C1 and C2 genes, suggesting that they may have arisen by duplications of an ancestral gene. Finally, homologous human genes have not been detected.     

Local mutagenesis of Rous sarcoma virus: The major sites of tyrosine and serine phosphorylation of p60src are dispensable for transformation

We have constructed mutants of Rous sarcoma virus expressing p60^src that are underphosphorylated on serine or tyrosine, by linker insertion or insertion/ deletion into cloned Rous sarcoma virus DNA, and recovery of mutant virus by transfection of chicken embryo fibroblasts. Cells infected with mutants whose p60^src lack the major site of either serine or tyrosine phosphorylation were morphologically transformed and formed colonies in soft agar. The tyrosine kinase activities of the mutant p60^src measured in vivo and in vitro were close to the wild type activity. Peptide mapping showed that phosphorylation on tyrosine and serine of p60^src is independent: the major phosphorylated tyrosine and the major phosphorylated serine can each be phosphorylated in the absence of phosphorylation of the other.     

HEMOPOIETIC STEM CELL PROLIFERATION AND MIGRATION FOLLOWING BORDETELLA PERTUSSIS VACCINE

The ability of a single injection of killed, intact bacteria to effect an increase in the proliferative rate of hemopoietic stem cells was studied. The total numbers of colony forming units in bone marrow, spleen and peripheral blood as well as the proportion of CFU in cycle was assessed. Splenic CFU were observed to rise exponentially due initially to in situ proliferation and later to proliferation in bone marrow with migration via the blood to the spleen. The results are discussed in the light of current concepts of stem cell regulation.     

Ultrastructure and distribution of microbodies in leaves of grasses with and without CO2-photorespiration

Summary A comparative study was made of the ultrastructure, distribution and abundance of leaf microbodies in four species of temperate grasses with high and four tropical grasses with low CO₂-photorespiration. The temperate grasses were all festucoid; the tropical grasses included two panicoid species and two chloridoid. Comparisons of relative abundance were made by computing the average numbers of microbody profiles per cell section.Although microbodies were present in the green parenchymatous leaf cells in all grasses examined, their average number per cell was in general severalfold greater in the grasses with high CO₂-photorespiration than in those with low. Furthermore, whereas in the grasses with high CO₂-photorespiration the microbodies were distributed through the mesophyll, in those with low CO₂-photorespiration they were concentrated in the vascular-bundle-sheath cells and were smaller and relatively scarce in the mesophyll cells. The leaf microbodies of the eight grass species resembled one another in general morphology, but differed to some extent in regard to size and type of inclusion. Microbodies of all four festucoid species contained numerous fibrils with a discernible substructure. Those of the two panicoid species contained clusters of round bodies with transparent cores. The equivalence of the microbodies to peroxisomes as biochemically defined was shown cytochemically by employing 3,3-diaminobenzidine for the localization of catalase, a marker enzyme for the peroxisome. This reaction was blocked by the catalase inhibitor, aminotriazole.The observations on the relative abundance and distribution of peroxisomes in leaves of grasses with high CO₂-photorespiration versus those with low are consistent with the published biochemical data on the levels and distribution of peroxisomal enzymes in representatives of plants with high and low CO₂-photorespiration, and may help explain the differences in apparent photorespiratory levels between these two groups of plants.     

Culture Medium for Enterobacteria

A new minimal medium for enterobacteria has been developed. It supports growth of Escherichia coli and Salmonella typhimurium at rates comparable to those of any of the traditional media that have high phosphate concentrations, but each of the macronutrients (phosphate, sulfate, and nitrogen) is present at a sufficiently low level to permit isotopic labeling. Buffering capacity is provided by an organic dipolar ion, morpholinopropane sulfonate, which has a desirable pK (7.2) and no apparent inhibitory effect on growth. The medium has been developed with the objectives of (i) providing reproducibility of chemical composition, (ii) meeting the experimentally determined nutritional needs of the cell, (iii) avoiding an unnecessary excess of the major ionic species, (iv) facilitating the adjustment of the levels of individual ionic species, both for isotopic labeling and for nutritional studies, (v) supplying a complete array of micronutrients, (vi) setting a particular ion as the crop-limiting factor when the carbon and energy source is in excess, and (vii) providing maximal convenience in the manufacture and storage of the medium.     

Inactivation of Poliovirus Type 1 by the Kelly-Purdy Ultraviolet Seawater Treatment Unit

Three experiments were conducted to determine the effect of ultraviolet (UV) radiation on poliovirus-contaminated seawater. In two of the experiments, the effectiveness of the Kelly-Purdy UV Seawater Treatment Unit to inactivate poliovirus type 1 (T(1)) suspended in continuously flowing seawater was determined. In experiment 1, the observed survival ratio of poliovirus T(1) was 2.3 x 10(-4) (99.98% reduction) in 15.7 sec. No virus was detected (<0.2 plaque-forming unit/ml) in 20.6 seconds. The calculated half-life value was 1.29 sec. In experiment 2, the observed survival ratio of poliovirus T(1) was 5.9 x 10(-4) (99.94% reduction) in 11.7 sec. No virus was detected in 15.7 sec. The calculated half-life value was 1.37 sec. In experiment 3, a laboratory-controlled UV experiment designed to closely simulate the geometry of the continuously flowing seawater system, the observed survival ratios of poliovirus T(1) were 9.7 x 10(-3) (99.03% reduction) and 3.6 x 10(-4) (99.96% reduction) in 15 and 30 sec, respectively; the calculated half-life value was 2.38 sec. A statistically significant difference was found between the inactivation rates of poliovirus T(1) in the two test systems. This rate difference was attributed primarily to UV dosage and stirring effects. The data indicated that UV radiation effectively inactivated poliovirus T(1) in flowing seawater. These results validate the efficacy of the Kelly-Purdy UV Seawater Treatment Unit for use in commercial depuration systems.