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%).     

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.     

Isolation and characterization of a new 40-kilodalton protein from bovine cardiac muscle

A new protein having a subunit weight of 40,000 has been purified from myosin-extracted bovine cardiac myofibrils. Its amino acid composition and isoelectric point are distinct from actin, eu-actinin, and a variety of sarcoplasmic proteins of similar size. Affinity-purified antibodies made to this protein only react with a single 40-kDa protein band from cardiac myofibrils on immunoblots. The anti-40-kDa protein also shows cross-reactivities with cardiac myofibrils from rabbits, rats, and chickens. Immunofluorescence studies demonstrate that the 40-kDa protein is localized at the Z-bands of cardiac myofibrils and at the intercalated discs. The antibody did not react with skeletal muscle myofibrils by immunofluorescence or immunoblotting. It appears that the 40-kDa protein may play a role in the strong attachments between adjacent myofibrils in cardiac muscle.     

Independence of exercise hyperpnea and acidosis during high-intensity exercise in ponies

We investigated arterial PCO2 (PaCO2) and pH (pHa) responses in ponies during 6-min periods of high-intensity treadmill exercise. Seven normal, seven carotid body-denervated (2 wk-4 yr) (CBD), and five chronic (1-2 yr) lung (hilar nerve)-denervated (HND) ponies were studied during three levels of constant load exercise (7 mph-11%, 7 mph-16%, and 7 mph-22% grade). Mean pHa for each group of ponies became alkaline in the first 60 s (between 7.45 and 7.52) (P less than 0.05) at all work loads. At 6 min pHa was at or above rest at 7 mph-11%, moderately acidic at 7 mph-16% (7.32-7.35), and markedly acidic at 7 mph-22% (7.20-7.27) for all groups of ponies. Yet with no arterial acidosis at 7 mph 11%, normal ponies decreased PaCO2 below rest (delta PaCO2) by 5.9 Torr at 90 s and 7.8 Torr by 6 min of exercise (P less than 0.05). With a progressively more acid pHa at the two higher work loads in normal ponies, delta PaCO2 was 7.3 and 7.8 Torr by 90 s and 9.9 and 11.4 Torr by 6 min, respectively (P less than 0.05). CBD ponies became more hypocapnic than the normal group at 90 s (P less than 0.01) and tended to have greater delta PaCO2 at 6 min. The delta PaCO2 responses in normal and HND ponies were not significantly different (P greater than 0.1).(ABSTRACT TRUNCATED AT 250 WORDS)     

Leishmania mexicana pifanoi: in vivo and in vitro interactions between amastigotes and macrophages

Macrophages of the cell line J774 were used in a comparative study of virulence involving amastigote stages of Leishmania mexicana pifanoi isolated from macrophages (AMA-M) of the aforementioned cell line, amastigote forms grown in the UM-54-cell-free medium (AMA-C), and promastigote stages. The macrophage cultures were inoculated with AMA-M and AMA-C at the culture cell to parasite ratios of 1:3, 1:5, and 1:10. The macrophages were exposed to either kind of amastigotes for 24, 48, and 72 h. At the end of each of these periods, and for each dilution, the percentages of macrophages harboring the parasites within their cytoplasm and the mean numbers of intracellular parasite/macrophage were estimated on the basis of examination of 200 phagocytes. When either AMA-M or AMA-C were employed, after 24 h, the percentages of infected macrophages were, respectively, 84.5%, 89.0%, and 94.5% for the three aforementioned dilutions, the majority of the phagocytes containing 1-5 parasites. After 48- and 72-h exposures, the macrophages harbored 6-11 and 11-20 amastigotes/cell, respectively. Evidently intracellular multiplication of the amastigotes has taken place. In contrast to the results obtained with amastigote forms, after inoculations of the macrophages cultures with promastigotes at the dilutions previously used for amastigotes, only 48-78 phagocytes were found to contain intracellular stages within their cytoplasm. Many macrophages were parasite-free, especially when exposed to fewer promastigotes. Experiments in which 5 X10(6) promastigotes, AMA-M, or AMA-C were inoculated into the footpads of hamsters yielded the following results with regard to terminal footpad volumes: 1.57, 3.31, and 3.32 cm3, respectively. Evidently both kinds of amastigotes had equal virulence for hamsters; however, the promastigote stages were much les virulent for these experimental hosts.