The structure of O-methyllythrine hydrobromide

Zusammenfassung Die Struktur des O-Methyl-lythrinhydrobromids wurde r?ntgen-kristallographisch ermittelt. Durch den oxydativen Abbau wurde das Hydrobromid mit dem unsubstituierten Lythrin verknüpft. Die Massenspektren zeigten, dass eine Reihe von weiteren Lythraceae-Alkaloiden das gleiche Grundgerüst besitzen.      

Comparison of preparations of erythrocyte membranes and membrane proteins by SDS-Gel electrophoresis

Résumé Quelques préparations de membranes érythrocytaires et de leurs protéines extraites en phase aqueuse ont été comparées par électrophorèse sur gel de SDS-polyacrylamide. De faibles différences seulement ont été notées d'une préparation à l'autre. Les extraits obtenus à force ionique basse ou élevée contiennent tous la même protéine de poids moléculaire élevé (spectrine) mais different quant à leur contenu en peptides de faible poids moléculaire. Les préparations obtenues à l'intérieur de chaque groupe s'avèrent fondamentalement semblables.

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We would like to thank Dr.Paul Bredderman for many discussions about gel electrophoresis. This work was supported by postdoctoral fellowship No. 34600 from the National Heart and Lung Institute, and by USPHS Grant No. AM1548-03. This paper is also based on work performed under contract with the U.S. Atomic Energy Commission at the University of Rochester Atomic Energy Project and has been assigned Report No. UR-3490-239.     

Absorption and biotransformation of L(+)-tartaric acid in rats

Summary Oral or parenteral doses of monosodium¹⁴C-L(+)-tartrate (400 mg/kg) are rapidly excreted by rats and a proportion completely metabolized to CO₂. The oral dose was well-absorbed.     

Flow-induced release of adenosine 5'-triphosphate from endothelial cells of the rat mesenteric arterial bed.

Adenosine 5'-triphosphate (ATP) was released into the perfusate of rat isolated mesenteric arterial beds during each of two consecutive increases in flow. There was no significant difference between the amounts of ATP released on each occasion. Substance P was also released into the perfusate by increased flow, although its release was more variable. Removal of the endothelium of the mesenteric vessels with sodium deoxycholate led to a significant reduction (74%) in the amount of ATP released compared with the release before the endothelium had been removed. This suggests that the ATP released into the mesenteric arterial perfusate during increased flow arises from endothelial cells.     

Turnover of sex chromosomes induced by sexual conflict

Sex-determination genes are among the most fluid features of the genome in many groups of animals. In some taxa the master sex-determining gene moves frequently between chromosomes, whereas in other taxa different genes have been recruited to determine the sex of the zygotes. There is a well developed theory for the origin of stable and highly dimorphic sex chromosomes seen in groups such as the eutherian mammals. In contrast, the evolutionary lability of genetic sex determination in other groups remains largely unexplained. In this theoretical study, we show that an autosomal gene under sexually antagonistic selection can cause the spread of a new sex-determining gene linked to it. The mechanism can account for the origin of new sex-determining loci, the transposition of an ancestral sex-determining gene to an autosome, and the maintenance of multiple sex-determining factors in species that lack heteromorphic sex chromosomes.