Isolation and partial sequence of goat spleen prothymosin α

Goat prothymosin , a highly acidic polypeptide of pl 3.5, 109 amino acid residues, has been isolated from lymphoid and non-lymphoid tissues of young female goats. Unlike rat, murine and porcine prothymosins , goat prothymosin appears at a higher concentration in the spleen compared with the thymus. The sequence of segments of the polypeptide involving known mutations has been determined, by automatic sequencing of its tryptic peptide fragments. The acidic amino acid-rich segment in the middle of the molecule, including residues 49–83, has not been sequenced. Goat prothymosin closely resembles bovine prothymosin , with only one substitution, proline for alanine at position 85. It also resembles human prothymosin , with only three substitutions. It differs more significantly from rat and murine prothymosins , by two deletions and three substitutions. The results show the highly conserved nature of the molecule, with substitutions at given positions only.Abbreviations ProT Prothymosin - T₁ Thymosin ₁ - MLR Mixed Lymphocyte Response - HPLC High Performance Liquid Chromatography - RIA Radioimmunoassay - B Aspartic acid or Asparagine - Z Glutamic acid or Glutamine     

室旁核在剌激猫肾神经传入纤维引起的血压效应中的应用

The purpose of this study is to investigate the role of paraventricular nucleus of the hypothalamus (PVN) and alpha 1 adrenergic receptor of PVN in the pressor responses to stimulation of renal afferent nerve in alpha 1-chloralose-anesthetized cats with carotid sinoaortic denervation and vagotomy. The pressor response to stimulation of renal afferent nerve consisted of a primary and a second components. The primary component response was completely blocked while the second component was not blocked by autonomic blocking agents (hexomethonium and atropine). Bilateral lesions of PVN greatly attenuated the pressor response before and after autonomic blockade. Intracerebroventricular and PVN injection alpha 1, adrenergic antagonist (prazosin) significantly decreased in the pressor response to stimulation of renal afferent nerve. These results indicate that paraventricular nucleus of the hypothalamus and alpha 1 adrenergic receptors in central nervous system, especially in PVN, play an important role in the pressor responses to stimulation of renal afferent nerve.     

Spontaneous Activation of Quiescent Uq Transposable Elements during Endosperm Development in Zea Mays

This study addresses the question of the activation of quiescent transposable elements in maize breeding lines. The a-ruq reporter allele of the Uq transposable element system expresses Uq activity (spots or sectors of spots in otherwise colorless aleurone tissue) when exposed to various genotypes of assorted maize inbred lines lacking any active Uq element. This activation of quiescent Uq elements occurs randomly during the growth of the endosperm. It is concluded that there are components in the genome that enhance the rare activation of quiescent Uq elements. Further, it seems that this activation occurs in the absence of any stress-inducing treatment, but that normal growth conditions provide sufficient stimulus for such activation.     

Purification of duck growth hormone and cloning of the complementary DNA

Duck growth hormone (GH) was isolated and purified from duck pituitaries by salt precipitation and HPLC on reverse-phase C18 columns. The duck GH was homogeneous as shown by SDS-polyacrylamide gel electrophoresis with a molecular weight of 22,000. The cDNA was synthesized and cloned in Escherichia coli using EcoRI linkers and pBR322 as vector. The positive clones were selected and sequenced. The full-length duck GH cDNA contains 820 nucleotide pairs with an open reading frame coding for the precursor form duck GH of 216 amino-acid residues. The partial amino-acid sequence from the protein completely agrees with that derived from the cDNA, with Phe as the first residue in mature duck GH preceded by a 27-residue hydrophobic signal peptide. The duck GH is almost completely homologous to the chicken GH, with only three conservative substitutions (Ser for Thr, His for Tyr and Lys for Arg) and one deletion (Ala) in the duck GH sequence. Comparison of amino-acid sequence of duck GH with that of various species reveals 56%, 73% and 40% homologies with GHs of human, rat and salmon, respectively.     

Cloning and sequencing of bullfrog growth hormone complementary DNA

Total mRNA was isolated from the pituitary glands of bullfrog (Rana catesbeiana), purified by affinity chromatography with oligo(dT)-cellulose columns. The cDNA was synthesized and cloned in Escherichia coli using EcoRI linkers and pBR322 as vector. The cDNA library was screened by hybridization with 32P-labeled duck growth hormone (GH) cDNA. A positive clone was selected and sequenced. The full-length bullfrog GH cDNA contains 950 nucleotide pairs with an open reading frame coding for the precursor GH of 215 amino-acid residues. The partial amino-acid sequence from the protein confirms that derived from the cDNA, with Phe as the first residue in the mature bullfrog GH preceded by a 25-residue hydrophobic signal peptide. The bullfrog GH shares sequence homology with those of other vertebrate species in the following order: duck (61% protein sequence homology; 67% cDNA homology), rat (56%; 61%), human (47%; 57%) and salmon (42%; 50%).     

Monoclonal antibodies specific for type 3 protein kinase C recognize distinct domains of protein kinase C and inhibit in vitro functional activity

Monoclonal antibodies (mAbs) which distinguish Type 3 protein kinase C (PKC) from Types 1 and 2 have been obtained from mice immunized with purified Type 3 PKC from rabbit brain cytosol. Most of these mAbs (seven out of eight) selectively recognize Type 3 versus Types 1 and 2 PKC in both enzyme-linked immunosorbent and immunoblot assays. Trypsin treatment of Type 3 PKC reduced the immunoreactivity with 82-kDa PKC and generated immunoreactive fragments of 45 and 35 kDa. The mAbs can be divided into two classes based on their ability to recognize the 45-kDa catalytic fragment (5/8) or the 35 kDa regulatory domain fragment (3/8). Each of the mAbs inhibits phosphorylation of histone or lipocortin by PKC, although the extent of the inhibition varied. Only those mAbs that recognize the 35-kDa regulatory domain inhibited phorbol ester binding. The inhibition of both kinase and binding activities by this group of mAbs was sensitive to the concentration of phospholipid used in the assay. This functional inhibition suggests that these mAbs may be useful for defining the phospholipid binding domain(s) of Type 3 PKC. The mAbs recognized 82-kDa PKC in a variety of cell types; the presence of smaller molecular weight fragments was not consistently found. Distinct immunofluorescence staining patterns were observed with mAbs directed toward different epitopes, suggesting that there may be heterogeneity in the subcellular localization of PKC. The type specificity of these mAbs will make them valuable tools for studying activation and regulation of Type 3 PKC in cell culture model systems.     

Selective inhibition of glycoprotein-processing enzymes. Differential inhibition of glucosidases I and II in cell culture

In this study, we compared the effects of 2,6-dideoxy-2,6-imino-7-O-(beta-D-glucopyranosyl)-D-glycero-L-gulohep titol (MDL) to those of the glucosidase I inhibitor, castanospermine, on the purified processing enzymes glucosidases I and II. WE also compared the effects of these two inhibitors on glycoprotein processing in cell culture using influenza virus-infected Madin-Darby canine kidney cells as a model system. With the purified processing enzymes, castanospermine was a better inhibitor of glucosidase I than of glucosidase II, whereas MDL is more effective against glucosidase II than glucosidase I. In cell culture at the appropriate dose, MDL also preferentially affected glucosidase II. Thus, at 250 micrograms/ml MDL, the major [3H]glucose-labeled (or [3H]mannose-labeled) glycopeptide from the viral hemagglutinin was susceptible to endoglucosaminidase H, and the oligosaccharide liberated by this treatment was characterized as a Glc2Man7-9GlcNAc on the basis of size, resistance to digestion by glucosidase I (but sensitivity to glucosidase II), methylation analysis, and Smith degradation studies. These data indicate that at appropriate concentrations of MDL (250 micrograms/ml), one can selectively inhibit glucosidase II in Madin-Darby canine kidney cells. However, at higher concentrations of inhibitor (500 micrograms/ml), both enzymes are apparently affected. Since MDL did not greatly inhibit the synthesis of lipid-linked saccharides or the synthesis of protein or RNA, it should be a useful tool for studies on the biosynthesis and role of N-linked oligosaccharides in glycoprotein function.     

Biomass yields and energetic yields of oleaginous yeasts in batch culture

This article provides the analysis on biomass yields and energetic yields of the oleaginous yeasts. The biomass yields of the oleaginous yeasts are consistently lower than nonoleaginous microorganisms, whereas their energetic yields are higher. Data inconsistencies of literature are explained by the variation of energy contents of oleaginous yeasts.     

Studies on the phospholipid composition of pathogenic cell membranes of Mycoplasma hyopneumoniae

The membrane phospholipid and fatty acid compositions of Mycoplasma hyopneumoniae, a pathogen of porcine enzootic pneumoniae isolated in China, was studied by thin-layer chromatography and gas chromatography. The results showed that membrane phospholipids consisted predominantly of diphosphatidylglycerol. The percentage of C16 - C18 fatty acids comprised 79% of the total fatty acids, of which oleic acid as well as palmitic acid are the major fatty acids. Some differences were shown in fatty acid composition as compared with membranes of other species of Mycoplasma.     

Human liver alkaline phosphatase, purification and partial sequencing: homology with the placental isozyme

Human liver alkaline phosphatase (AP) has been purified to homogeneity. The enzyme has a molecular weight of 150,000 in its native state and consists of two identical subunits of Mr 75,000. After treatment with endoglycosidase F the molecular weight is reduced to 50,000 indicating a high degree of glycosylation. The amino-terminal sequence up to 22 residues was found to be Leu-Val-Pro-Glu-Lys-Glu-Lys-Asp-Pro-Lys-Tyr-(Ala)-Arg-Asp-Gln-Ala-Gln-?- Thr-Leu-Lys-Tyr. The amino-terminal portions of human and bovine liver AP are identical. The amino termini of the human liver and human placental AP isozymes have appreciable homology. Conformationally the amino termini are very similar.