Stabilization of steroid 11-hydroxylation activity ofCunninghamella elegans protoplasts in organic osmotic stabilizers

Protoplasts ofCunninghamella elegans, showing 11-, and 11-hydroxylating ability of Substance S, preserved high transformation activity when dispersed in glucose-enriched, organic osmotic stabilizers. A joint action of polyoxins and 2-deoxy-d-glucose was necessary to prevent regeneration of the cell wall in long-lasting experiments. Stabilized and active, dispersed protoplasts may be an alternative research model for studying the function of the cell wall and intracellular metabolic pool constituents in steroid hydroxylation.     

The effect of different krill meals fed to laboratory rats on their blood indices.

1. In 102 laboratory rats fed with (a) the krill standardized meal, (b) the krill meal with low chitin content, (c) the casein diet with D,L-methionine, (d) the casein diet with D,L-methionine supplemented with the krill carapace meal, (e) the casein diet with D,L-methionine supplemented with ash from the krill standardized meal and (f) the control diet--"Murigran" standard pelleted feed; the different blood indices were investigated. 2. The mean values of following indices: the number of erythrocytes and leucocytes, the percentage of leucocytes, the corpuscular haemoglobin concentration and red blood cell diameter were similar in all experimental and control groups. 3. The mean values of haematocrit and haemoglobin levels, the mean corpuscular thickness and volume were lower in rats fed with the casein diet with D,L-methionine supplemented with the krill carapace meal than in other groups. 4. All kinds of investigated indices were similar in rats fed with krill meal with low chitin contents, whose parents received the standardized krill meal and no sex differences have been shown here.     

Specific incorporation of glycine into bacterial lipopolysaccharide. Novel function of specific transfer ribonucleic acids.

It has been found that the bacterial endotoxins (lipopolysaccharides, LPSs) contain some amino acids and glycine is the most abundant amino acid in the polysaccharide core preparations of LPSs of gram-negative bacteria. Until now nothing was known about the mechanism of amino acid incorporation into the lipopolysaccharide core. We found that one out of three glycyl-tRNAs(Gly) from Escherichia coli is the donor of amino acid and is the substrate for a putative aminoacyl-tRNA:LPS transferase. We have isolated, purified this tRNA and determined its nucleotide sequence to be major E.coli tRNA(3Gly). This tRNA(Gly) (anticodon GCC) conserved the tRNA structural features. The assay for determination of the specific incorporation of glycine into the lipopolysaccharide was also invented and described.     

CTP-dependent lipid kinases of yeast

Membrane fractions from yeast Saccharomyces cerevisiae catalyzed a transfer of gamma-phosphate from [gamma-32P]CTP into membranous lipids. Phosphorylated compounds were identified as phosphatidic acid and dolichyl phosphate (DolP). The membrane fraction also catalyzed phosphorylation of the exogenous dolichol. The activity of the phosphorylating enzymes could be modified by the yeast growing conditions; i.e., the enzyme from yeast grown aerobically favored the synthesis of phosphatidate over dolichyl phosphate in the ratio of 3:1, whereas the membrane fraction from anaerobically grown yeast synthesized PA and DolP in the ratio of 0.5:1. The activity of the phosphorylating enzymes could also be modified by divalent cations and the concentration of detergents. Phosphorylation of lipids does not occur in the presence of [gamma-32P]ATP and is not influenced by the presence of UTP or GTP. This result points to the specific role of CTP as a gamma-phosphate donor for the synthesis of phosphatidate and dolichyl phosphates in the yeast system.     

Cytogenetics of the European plethodontid salamanders of the genus Hydromantes (Amphibia,Urodela)

A karyological analysis was carried out on different European species of the genus Hydromantes (Plethodontidae). All the species examined share the same chromosome number (2n=28) and, with the exception represented by pair XIV, morphologically similar karyotypes. While the karyotypes display a similar distribution — mainly centromeric and pericentric — of C-heterochromatin, quantitative variations in pericentric heterochromatin are observed among species. In the continental species Hydromantes italicus and ambrosii as well as in the eastern Sardinian species imperialis, flavus and specie nova, pair XIV consists of heteromorphic sex chromosomes of the XX/XY type. It is proposed that the differentiation of the Y might have taken place through the occurrence of a structural rearrangement, such as a pericentric inversion, starting from a hypothetical, homomorphic pair XIV. A sex-related heteromorphism is not found in the western Sardinian species H. genei. A further karyological differentiation among these species concerns the position of the nucleolus organizing region (NOR), which is located on chromosome XII (H. italicus and ambrosii) or on chromosome X, close to the centromere (H. genei, H. imperialis and H. specie nova), or in an intercalary position (H. flavus). The location and the number of the 5 S DNA sites have been conserved during species divergence. On the basis of these karyological data, as well as of results obtained through a preliminary restriction enzyme analysis of the ribosomal and genomic DNAs, the phyletic relationships among the European Hydromantes species are discussed.     

Binding of Germanium to Pseudomonas putida Cells

The binding of germanium to Pseudomonas putida ATCC 33015 was investigated by using whole intact cells grown in a medium supplemented with GeO₂ and catechol or acetate. Electron-microscopic examination of the control and metal-loaded samples revealed that germanium was bound within the cell envelope. A certain number of small electron-dense deposits of the bound element were found in the cytoplasm when the cells were grown in the presence of GeO₂ and catechol. The study of germanium distribution in cellular fractions revealed that catechol facilitated the intracellular accumulation of this element.     

Glucuronides of monohydroxylated bile acids: specificity of microsomal glucuronyltransferase for the glucuronidation site, C-3 configuration, and side chain length

The ability of rat liver microsomes to catalyze UDP-glucuronic acid-dependent glucuronidation of monohydroxy-bile acids was examined. The following bile acids were used as substrates, each as the 3 alpha and 3 beta epimer: 3-hydroxy-5 beta-cholanoic acid (C24), 3-hydroxy-5 beta-norcholanoic acid (C23), 3-hydroxy-5 beta-bisnorcholanoic acid (C22), 3-hydroxy-5 beta-pregnan-21-oic acid (C21), and 3-hydroxy-5 beta-androstane-17 beta-carboxylic acid (C20). The corresponding glucuronides were chemically synthesized to serve as standards and were characterized by thin-layer and gas-liquid chromatography as well as by nuclear magnetic resonance. Enzymatic glucuronidation reactions were optimized with respect to pH for each product formed and the kinetic parameters for each reaction were measured. Analytical techniques necessary to separate products from unreacted substrates and to identify them included thin-layer chromatography, gas-liquid chromatography, and nuclear magnetic resonance. It was found that the 3 alpha epimers of the five bile acids listed above enzymatically formed 3-O-glucuronides, C24 being the best substrate, followed by C21 and C20; C22 and C23 gave rise to only small amounts of this product. The 3 beta epimers of all bile acids tested were poorer substrates, although by a factor that varied widely. In addition to the expected hydroxyl-linked glucuronide, three of the 3 alpha-bile acids (C23, C22, and C20) and at least one 3 beta-bile acid (C20), gave rise to a novel metabolite in which the 1-OH of glucuronic acid was esterified with the steroidal carboxyl group (carboxyl-linked glucuronide).     

The composition of liver chromatin proteins from embryos, chicks and adult chickens

The chemical composition of chromatin from the livers of 12-, 15- and 19-day-old embryos, of 1-day-old chicks and of adult chickens was analysed. The process of embryonic development is accompanied by an increase in non-histone chromatin proteins and chromatin RNA, as well as in the phosphorus content of chromatin phosphoproteins. The amount of these components decreases in the livers of 1-day-old chicks and adults. Two-dimensional polyacrylamide gel electrophoresis of acid-soluble chromatin proteins showed an increase in the amount of the H1 histone in 19-day-old embryos and adult chickens. Non-histone proteins of embryo liver chromatin showed a high content of the fraction of Mr of about 40 000; this was not the case for adult chickens. The non-histone protein fraction of Mr of about 120 000, characteristic of adult chicken liver proteins, was not found in the livers of 12- and 15-day-old embryos. Non-histone chromatin proteins isolated from the livers of animals of different age exhibited also quantitative differences.     

Immunological analysis of histone H2A from the slime mold Physarum polycephalum

Specific antibodies against the histone H2A from calf thymus were generated by injecting rabbits with complexes: histone H2A-RNA with a protein to RNA ratio of 3:1. In the microcomplement fixation assay the antibodies against the histone H2A from calf thymus immuno-reacted with the histone H2A from calf thymus but not with H2A from Physarum polycephalum. The histone H2A from calf thymus therefore appears to have an immunological determinant(s) which does not exist in H2A from Physarum polycephalum.     

Differential regulation of the brain and gut immunoreactive dynorphin by the serotonin system

Administration of drugs such as fenfluramine, 20-40 mg/kg, and m-chlorophenylpiperazine (m-CPP), 2.5-5 mg/kg, which release serotonin or activate postsynaptic serotonin receptors, respectively, induced a dramatic decrease in the duodenal content of immunoreactive dynorphin (ir-DYN). The effect was antagonized by cyproheptadine, 1 mg/kg. Similarly, acute administration of the specific serotonin reuptake blockers fluvoxamine, 15 mg/kg, or femoxetine, 10 mg/kg, and 5-hydroxytryptophan (5-HTP), 40-160 mg/kg, evoked a marked decrease in the duodenal content of ir-DYN. A combined administration of fluvoxamine or femoxetine and 5-HTP failed to potentiate the effect of individual treatment. Only a higher dose of fenfluramine, 40 mg/kg, increased the ir-DYN content in the hypothalamus. These results suggest that the brain and gut ir-DYN is independently regulated by the serotonin system and that a serotonin mechanism might stimulate release of the gut dynorphin content.