The proteins of the ejaculatory bulbs in different species of Drosophila

A comparative electrophoretic study or ejaculatory bulb proteins in 29 different Drosophila species has been carried out. In all analyzed species, ejaculatory bulb contains a major component (designated as PEB). It has molecular mass of 61-65 kDa in the species of virilis group, 33-36 kDa in species of obscura group, and 34-56 kDa in species of melanogaster group. Using immunoblotting technique, we have demonstrated that PEB is introduced into organs of female sex tract during mating. The nature and significance of revealed interspecific differences in PEB proteins has been discussed.     

Characteristics of carbohydrate metabolism in the rat liver in thiamine deficiency

Thiamine deficiency in rats induced by oxythiamine is accompanied by an increase in the free NADP+/NADPH ratio in liver tissue, which results in multifold stimulation of the metabolite flux in the oxidation branch of the pentose cycle. The increase in the intracellular concentrations of isocitrate and alpha-ketoglutarate with a simultaneous decrease of malate in the liver of vitamin-deficient rats points to the inhibition of alpha-ketoglutarate dehydrogenase responsible for the anomalous metabolism under conditions of thiamine deficiency. The decrease of the functional activity of the tricarboxylic acid cycle is concomitant with the activation of conversions in the oxidation branch of the pentose cycle, glucuronate and glycolytic pathways of carbohydrate metabolism, which is directed at eliminating the energy deficiency in rats with B1-hypovitaminosis.     

Investigation of the enzymic and electrochemical oxidation of uric acid derivatives.

The electrochemical oxidation of a number of N-methylated uric acids at the pyrolytic graphite and gold electrodes has been compared to their enzymic oxidation with type VIII peroxidase and H2O2. Spectral, electroanalytical and kinetic evidence supports the conclusion that for all compounds the electrochemical and enzymic reactions proceed by identical mechanisms.     

Genetic analysis of hypertropic mutants of Phycomyces

A new class of Phycomyces behavioral mutants with enhanced tropic responses has been analyzed genetically to determine the number of genes involved and the nature of their expression. These hypertropic mutants carry pleiotropic nuclear mutations. Besides their effects on sensory behavior, they also affect morphology and meiotic processes. Behavioral analyses of heterokaryons containing hypertropic and wild-type nuclei in varying proportions show that the hypertropic mutations in strains L82, L84, L86, and L88 are strongly dominant. Conversely, the hypertropic mutations carried by the strains L83, L85, and L87 are strongly recessive. We performed recombination analyses between hypertropic mutants and mutants with diminished phototropism, affected in the seven genes madA to madG. We found no evidence of linkage between the hypertropic mutations and any of these mad mutations. From crosses, we isolated double mutants carrying hypertropic mutations together with madC (night blind) and madG (stiff) mutations. The behavioral phenotypes of the double mutants are intermediate between those of the parentals. Complementation analyses show that the three recessive hypertropic mutations affect the same gene, which we call madH. The expression of the recessive hypertropic allele becomes dominant in heterokaryons carrying madC and madH nuclei; the madC gene has been implicated separately with the photoreceptor at the input to the sensory pathway, while the madH gene is associated with the growth control output. This result suggests the physical interaction of both gene products, madH and madC, in a molecular complex for the photosensory transduction chain.     

Ferritin in normal human peripheral blood T-lymphocyte subpopulations

Six peripheral blood lymphoid fractions (total lymphocytes, non-T, T, Tar (autologous rosette-forming T cells/precursor), T mu (helper), and T gamma (suppressor) lymphocytes) isolated through rosetting procedures were examined for the presence of ferritin by a direct immunofluorescence technique. Although ferritin was present in all lymphoid fractions studied, a significantly higher proportion of ferritin-containing cells were detected in the T-cell fraction than in the non-T-cell fraction, (mean +/- SD = 7.9 +/- 1.6% and 5.0 +/- 1.2%, respectively). T mu- and T gamma-cell fractions showed a twofold increase in the number of ferritin-positive cells (14.1 +/- 1.4% and 15.4 +/- 2.6%, respectively), as compared with Tar (7.0 +/- 0.9%)-and total lymphocyte (6.9 +/- 1.3%)-cell fractions. These results indicate that ferritin is preferentially distributed in T mu and T gamma lymphocytes and may constitute the basis for explaining some of the roles exercised by these cells in the control of other biological systems.     

Group-selective reagent modification of the sodium- and chloride-coupled glycine transporter under native and reconstituted conditions.

Glycine transporter from rat brain stem and spinal cord is inactivated by specific sulfhydryl reagents. Modification of lysine residues also promotes a decrease of the transporter activity but in a lesser extent than that promoted by thiol group reagents. Mercurials showed a more marked inhibitory effect than maleimide derivatives. SH groups display a similar reactivity for p-chloromercuribenzenesulfonate (pCMBS) and mersalyl in synaptosomal membrane vesicles and proteoliposomes reconstituted with the solubilized transporter. However, different reactivity is observed with N-ethylmaleimide (MalNEt), the greatest effect being attained in membrane vesicles. The rate of inactivation by pCMBS and MalNEt is pseudo-first-order showing time- and concentration-dependence. pCMBS and MalNEt decrease the Vmax for glycine transport and to a lesser extent act on the apparent Km. Treatment with dithiothreitol (DTT) of the transporter modified by pCMBS results in a complete restoration of transporter activity indicating that the effect exercised by the reagent is specific for cysteine residues on the protein. It is concluded that SH groups are involved in the glycine transporter function and that these critical residues are mostly located in a relatively hydrophilic environment of the protein.