The protein-coding sequence of the bovine ACTH-beta-LPH precursor gene is split near the signal peptide region

The pituitary hormones corticotropin (ACTH) and beta-lipotropin (beta-LPH) are formed from a large common precursor. Recently, we have elucidated the whole primary structure of the bovine ACTH-beta-LPH precursor (designated alternatively as preproopiocortin) by determining the nucleotide sequence of cloned DNA complementary to the mRNA coding for the precursor protein. The amino acid sequence assigned has disclosed a characteristic repetitive structure of the ACTH-beta-LPH precursor. The repetitive units of the precursor protein each contain a melanotropin (MSH) sequence (alpha-, beta- or gamma-MSH) as well as other peptide components such as beta-endorphin and corticotropin-like intermediate lobe peptide (CLIP). The repetitive units as well as their peptide components are each bounded by paired basic amino acid residues, which apparently represent the sites of proteolytic processing. Several studies have confirmed the translational initiation site and protein structure assigned (see also ref. 11 and refs therein). In view of the recent knowledge about the organization of eukaryotic genes (see refs 12, 13 for reviews), it would be of particular interest to investigate the relationship between the repetitive structure of the ACTH-beta-LPH precursor containing different functional components and the arrangement of the protein-coding sequence in its gene. We have now isolated and characterized bovine genomic DNA fragments encoding this precursor protein and have demonstrated that the protein sequence is encoded by two non-consecutive DNA segments. An intron (intervening sequence) of approximately 2.2 kilobase pairs separates the smaller exon (mRNA-coding sequence), which contains the gene sequence encoding the signal peptide, from the larger exon, which contains the gene sequence for most of the protein structure, including the known biologically active component peptides.     

Genome sequence of the endocellular obligate symbiont of tsetse flies,Wigglesworthia glossinidia

Many insects that rely on a single food source throughout their developmental cycle harbor beneficial microbes that provide nutrients absent from their restricted diet. Tsetse flies, the vectors of African trypanosomes, feed exclusively on blood and rely on one such intracellular microbe for nutritional provisioning and fecundity. As a result of co-evolution with hosts over millions of years, these mutualists have lost the ability to survive outside the sheltered environment of their host insect cells. We present the complete annotated genome of Wigglesworthia glossinidia brevipalpis, which is composed of one chromosome of 697,724 base pairs (bp) and one small plasmid, called pWig1, of 5,200 bp. Genes involved in the biosynthesis of vitamin metabolites, apparently essential for host nutrition and fecundity, have been retained. Unexpectedly, this obligate's genome bears hallmarks of both parasitic and free-living microbes, and the gene encoding the important regulatory protein DnaA is absent.     

Numerical Simulation of Rotor-stator Interactions in a Transonic Compressor Stage

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Adoptive transfer of EAE-like lesions from rats with coronavirus-induced demyelinating encephalomyelitis

Viruses have been found to induce inflammatory demyelinating lesions in central nervous system (CNS) tissue of both animal and man, either by natural infections or after vaccination. At least two different pathogenic mechanisms have been proposed for these changes, a cytopathic viral infection of oligodendroglia cells with subsequent cell death, and a host immune reaction against virus and brain antigens. We now report the occurrence of cell-mediated immune reactions against basic myelin proteins in the course of coronavirus infections in Lewis rats. Infection of rats with the murine coronavirus JHM leads to demyelinating encephalomyelitis developing several weeks to months postinfection. Lymphocytes from these diseased Lewis rats can be restimulated with basic myelin protein (BMP) and adoptive transfer of these cells leads to lesions resembling those of experimental allergic encephalomyelitis (EAE) in recipients, which can be accompanied by a mild clinical disease. This model demonstrates that a virus infection in CNS tissue is capable of initiating an autoimmune response which may be of pathogenic importance.     

5-HT hyperpolarization of bullforg sympathetic ganglion cell membrane

Zusammenfassung Die Membran der sympathischen Ganglienzelle des Ochsenfrosches (Rana catesbiana) wird durch 5-HT depolarisiert; 5-HT erzeugt jedoch in Gegenwart von Nicotin eine Hyperpolarisation. Es scheint, dass sowohl die Depolarisation als auch die Hyperpolarisation von 5-HT durch direkte Wirkung auf die Zell-Membran zustande kommt. Die durch 5-HT erzeugte Hyperpolarisation zeigte ähnliche Eigenschaften wie des «slow IPSP» welches jedoch während der Entwicklung der 5-HT Hyperpolarisation stark zunimmt. Es wird vermutet, dass 5-HT wahrscheinlich nicht als Überträgerstoff für das «slow IPSP» in Frage kommt.