Compensatory growth of the ovaries,adrenal glands and kidneys in blinded,anosmic rats

Résumé Chez les rats qui ont subi une ablation de la glande pinéale, la présence simultanée de perte de vue et d'anosmie empèchent la croissance compensatoire de l'ovaire chez la femelle et celle des glandes surrénales chez la mâle. Une hypertrophie du rein provoquée expérimentalement après une néphrectomie unilatérale n'est pas modifiée par la perte de vue et l'anosmie.

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Supported by grant No. HD-06523, U. S. P. H. S.     

Acute effects of unilateral or bilateral superior cervical ganglionectomy on rat pineal N-acetyltransferase activity and melatonin content.

Acute bilateral superior cervical ganglionectomy (SCGX) completely prevents the nocturnal rises in pineal N-acetyltransferase (NAT) activity and melatonin content in male rats kept in light-dark cycles of 14:10. Unilateral SCGX causes the NAT and melatonin levels to be intermediate between those in sham-operated control rats and those in rats from which both ganglia had been removed.     

Acute effects of unilateral or bilateral superior cervical ganglionectomy on rat pineal N-acetyltransferase activity and melatonin content

Summary Acute bilateral superior cervical ganglionectomy (SCGX) completely prevents the nocturnal rises in pineal N-acetyltransferase (NAT) activity and melatonin content in male rats kept in light-dark cycles of 1410. Unilateral SCGX causes the NAT and melatonin levels to be intermediate between those in sham-operated control rats and those in rats from which both ganglia had been removed.Supported by NSF, grant No. PCM 77-05734.     

Structure of a bacterial ribonuclease P holoenzyme in complex with tRNA

Ribonuclease (RNase) P is the universal ribozyme responsible for 5'-end tRNA processing. We report the crystal structure of the Thermotoga maritima RNase P holoenzyme in complex with tRNA(Phe). The 154?kDa complex consists of a large catalytic RNA (P RNA), a small protein cofactor and a mature tRNA. The structure shows that RNA-RNA recognition occurs through shape complementarity, specific intermolecular contacts and base-pairing interactions. Soaks with a pre-tRNA 5' leader sequence with and without metal help to identify the 5' substrate path and potential catalytic metal ions. The protein binds on top of a universally conserved structural module in P RNA and interacts with the leader, but not with the mature tRNA. The active site is composed of phosphate backbone moieties, a universally conserved uridine nucleobase, and at least two catalytically important metal ions. The active site structure and conserved RNase P-tRNA contacts suggest a universal mechanism of catalysis by RNase P.     

The effect of various anions on the contractility of the guinea-pig papillary muscle

Zusammenfassung Ersatz der Chlorionen des Suspensionsmediums durch NO ₃ ^– , Br^– oder J^–verstärkt die Kontraktionskraft des Herzmuskels im Gegensatz zu der des Skelettmuskels durch Vergrösserung der Anstiegssteilheit der Kontraktion. Dagegen wirkt F^– (5 mM) am Herzen positiv inotrop durch Verlängerung der Anstiegszeit der Kontraktion.     

Vertebrate Smoothened functions at the primary cilium

The unanticipated involvement of several intraflagellar transport proteins in the mammalian Hedgehog (Hh) pathway has hinted at a functional connection between cilia and Hh signal transduction. Here we show that mammalian Smoothened (Smo), a seven-transmembrane protein essential for Hh signalling, is expressed on the primary cilium. This ciliary expression is regulated by Hh pathway activity; Sonic hedgehog or activating mutations in Smo promote ciliary localization, whereas the Smo antagonist cyclopamine inhibits ciliary localization. The translocation of Smo to primary cilia depends upon a conserved hydrophobic and basic residue sequence homologous to a domain previously shown to be required for the ciliary localization of seven-transmembrane proteins in Caenorhabditis elegans. Mutation of this domain not only prevents ciliary localization but also eliminates Smo activity both in cultured cells and in zebrafish embryos. Thus, Hh-dependent translocation to cilia is essential for Smo activity, suggesting that Smo acts at the primary cilium.