Response to Selection Under Non-Random Mating II. Prediction

A general expression for response to selection appropriate for both random and non-random mating situations is derived and illustrated with full-sibbing.     

Cell types of the pars distalis: seasonal changes in secretory activity and effect of steroids on spermatogenesis in Rana hexadactyla

Cytomorphological features and tinctorial affinities of the adenohypophyseal gonadotrophs have been studied in stained preparations of the pituitary of adult male frogs Rana hexadactyla Lesson, at monthly intervals during a calendar year. All the five morphologically distinct cell types showed a progressive increase in size from August of February, followed by a decrease from March to July. Extrusion of the synthetized product occurred in the summer and during this period production was low. Injection of steroids viz. stilboestrol, testosterone, oestradiol, doca and cortisol, interfered with the elaboration and secretion of gonadotropins, the adenohypophyseal feedback mechanism, and the sensitivity of the germinal epithelium. Changes in gonadotropins secretion and their impact on the testis are discussed.     

Enzymatic control of membrane lipids inMycobacterium smegmatis ATCC 607 grown at low temperature

Enzymes of phospholipid synthesis were studied inMycobacterium smegmatis ATCC 607 grown at 37 and 27°C. The synthesis seemed to be regulated, at least partly, at the phosphatidic acid level by the specificity of the acyltransferases. The individual phospholipid species were found to be regulated at the enzymatic level in the maintenance of membrane fluidity.     

Detection of endothelin-like immunoreactivity in epithelium and fibroblasts of the human umbilical cord

We studied tissue sections of freshly obtained full-term and premature human umbilical cords using polyclonal antibody to endothelin and immunocytochemistry. Endothelin immunoreactivity was detected in the cytoplasm of epithelial cells and primitive fibroblasts, but not in the endothelial cells of both full-term and premature umbilical cords. Immunoelectron microscopy using indirect immunogold staining technique localized endothelin immunoreactivity to the cytoplasm of the epithelial cells and fibroblasts but not confined to any particular structures. No endothelin immunoreactivity was detected in the nucleus or on the cell membrane. Pre-absorption tests with synthetic endothelin-1, -2, and -3 independently established that the immunoreactivity represented endothelin-1 and -2, but not -3. The presence of endothelin-1 and -2-like immunoreactive materials in epithelial cells and fibroblasts of human umbilical cord suggests a role of endothelin in parturition.     

Phytanic acid alpha oxidation in rat liver: studies on alpha hydroxylation

1. The alpha-hydroxylation of [1-14C]phytanic acid was investigated in the postnuclear fraction of rat liver. 2. The reaction required ATP, Mg, Fe3+ and molecular oxygen. Fe3+ could be replaced by Fe2+. 3. The hydroxylase activity was optimal at pH 7.5 in phosphate buffer. 4. The activity increased with postnuclear protein (5-13 mg or protein), increased with the substrate concentration at low substrate concentration. 5. The amount of the hydroxyacid formed increased with time up to 10 min. 6. Coenzyme A (100 microM-2.5 mM) stimulated the activity. 7. The activity was further stimulated by NADP and NADPH slightly and by FAD and FMN strongly, all at 100 microM concentration. 8. While CO inhibited the reaction, phenobarbital inducible cytochrome P-450 did not appear to play a role in this reaction.     

Tributyl phosphate biodegradation to butanol and phosphate and utilization by a novel bacterial isolate,Sphingobium sp. strain RSMS

A Sphingobium sp. strain isolated from radioactive solid waste management site (RSMS) completely degraded 7.98 g/L of tributyl phosphate (TBP) from TBP containing suspensions in 3 days. It also completely degraded 20 mM dibutyl phosphate (DBP) within 2 days. The strain tolerated high levels of TBP and showed excellent stability with respect to TBP degradation over several repeated subcultures. On solid minimal media or Luria Bertani media supplemented with TBP, the RSMS strain showed a clear zone of TBP degradation around the colony. Gas chromatography and spectrophotometry analyses identified DBP as the intermediate and butanol and phosphate as the products of TBP biodegradation. The RSMS strain utilized both TBP and DBP as the sole source of carbon and phosphorous for its growth. The butanol released was completely utilized by the strain as a carbon source thereby leaving no toxic residue in the medium. Degradation of TBP or DBP was found to be suppressed by high concentration of glucose which also inhibited TBP or DBP dependent growth. The results highlight the potential of Sphingobium sp. strain RSMS for bioremediation of TBP and for further molecular investigation.