Metabolism in porifera VI. Role of the 5,6 double bond and the fate of the C-4 of cholesterol during the conversion into 3β-hydroxymethyl-A-nor-5α-steranes in the spongeAxinella verrucosa

Summary During the conversion of cholesterol into 3 -hydroxymethyl-A-nor-5-cholestane by the spongeAxinella verrucosa, the carbon-3 of this latter originate from carbon-4 of cholesterol. Cholestanol moreover does not seem an intermediate in this conversion.     

Metabolism of 3β-hydroxycholest-5-en-26-oic acid in hamsters

Summary Metabolism of 26-hydroxycholesterol to 3-hydroxychol-5-en-24-oic acid and other C24-bile acids has been expected to occur by way of 3-hydroxycholest-5-en-26-oic acid in studies in vitro. 3-Hydroxycholest-5-en-26-oic acid was infused intravenously into bile fistula hamsters and the following C24-bile acids were identified: 3-hydroxychol-5-en-24-oic acid, lithocholic acid, chenodeoxycholic acid, and a small amount of cholic acid.     

Influence of cyproterone acetate on the activity ofβ-glucuronidase in the hypothalamus and cerebral cortex of the male mouse

Summary Daily s.c. injections of cyproterone acetate greatly decrease the protein content and-glucuronidase activity in the mouse hypothalamus. These effects are reversible and the recovery capacity of the animal seems to be inversely related to the duration of antiandrogenic treatment.Financial aid was given by CNR (finalized project Biologia della Riproduzione) and Ministry of Education. Thanks are also due to Prof. G. Chieffi for suggestions and to Mr R. Auriemma for maintenance of experimental animals.     

Histochemistry of steroid-3β-ol dehydrogenase in the human adrenal cortex

Zusammenfassung Bericht über histochemische Untersuchungen an menschlichen Nebennieren, die chirurgisch bei Fällen von inoperablem Mammacarcinom (mit oder ohne vorhergehende Stimulation mit exogenen ACTH) sowie bei Fällen von Cushingscher Krankheit entfernt worden waren.Anhand der Verteilung der verschiedenen Enzyme und insbesondere des Steroid-3-ol Dehydrogenase wird auf Fragen der Beziehungen der Morphologie und Funktion der normalen Drüse eingegangen und die Cushingsche Krankheit interpretiert.     

Influence of sex,developmental time and food onβ-N-acetylglucosaminidase activity in the rice weevilSitophilus oryzae L.

Summary The effects of some biological parameters on -N-acetylglucosaminidase activity have been investigated inS. oryzae. There is no significant influence of sex and developmental time on the enzyme activity level, which appears in contrast to be greatly influenced by food (wheat or sorghum). Sorghum contains competitive inhibitors which are almost completely removed after dialysis. Fasting relieves this inhibition very quickly, suggesting that inhibitors act directly at the gut level.     

Isotrinervi-2β-ol. Structural isomers in the defense secretions of allopatric populations of the termiteTrinervitermes gratiosus

Summary The defense secretions of 3 allopatric populations of the nasute termiteTrinervitermes gratiosus were analyzed. One population afforded a new trinervitene, isotrinervi-2-ol, a missing link in the hypothetical biosynthesis of the trinervitenes. Populations could be readily distinguished on the basis of the chromatographic profiles of their major and minor soldier frontal gland secretions.These studies were initiated (1975–76) with partial financial support by the International Centre of Insect Physiology and Ecology, Nairobi, Kenya and NIH Postdoctoral Fellowship AI-05076. Support by the Department of Chemistry of the State University of New York at Stony Brook and the technical assistance of Mr J. Engstrom allowed completion of this investigation.     

Sertoli cells of adult rats in vitro. II. Effect of different steroid precursors on estradiol 17β-synthesis

Summary The estradiol 17-synthesis by ⁴ pathway has been studied in homogenous cultures of Sertoli cells isolated from adult rat testes. The data reported clearly demonstrate that progesterone, androstenedione, testosterone and estrone induce an increase of the estradiol 17-production.This work was partially supported by grants No. 77.01322.04 and No. 77.01958.04 from the Consiglio Nazionale delle Ricerche.The excellent technical assistance of Antonio Muller and Massimo Rosati is deeply appreciated.     

Studies on the late-pre-β-lipoprotein of human serum

Summary Very low density lipoprotein (VLDL) isolated from 3 healthy normolipidaemic subjects had a raised VLDL cholesterol to triglyceride ratio. The VLDL fractions gave 2 pre--bands on agarose gel electrophoresis. Family study of the subjects appears to indicate sex linkage of this trait and a possible polygenic type of inheritance.Acknowledgment. This investigation was supported by a grant from University of Nigeria, Nsukka. I am grateful to Prof. Barry Lewis, St. Thomas Hospital Medical School, London, for his advice.     

Autoradiographic localization of the uptake of3H-β-alanine in rat nervous tissue cultures

Summary Autoradiographic studies on the uptake of³H--alanine have shown that, in spinal cord and brain stem cultures, both neurones and glial cells have accumulated the amino acid. In contrast, in cultures of cerebellum and dorsal root ganglia,³H--alanine was only taken up by glial elements.     

On the action ofβ-melanocyte stimulating hormone (β-MSH) on spontaneous electric discharge of the transparent knife fish,G. eigenmannia

Résumé L'hormone mélanophorétique-MSH, à des concentrations de 0.1 à 0.2µg/ml dans l'eau de l'aquarium, produit une diminution de la fréquence des modifications spontanées de l'amplitude des décharges électriques du poissonG. eigenmannia. Ces résultats sont en accord avec les observations antérieures montrant divers effets de-MSH sur l'activité électrique du système nerveux central chez les mammifères.     

In situ demonstration of the activity of 3β-hydroxysteroid dehydrogenase on steroid hormone secreting cells within the paraaortic lymph nodes of golden hamster

Summary The in situ activity of 3-hydroxysteroid dehydrogenase was detected in clustered cells which showed steroid-producing morphology, within the capsule of the paraaortic lymph node. In light and electron microscopic studies, the positive reaction products were detected on intracapsular cell clusters. This result indicates that these unique cells may have a steroid secreting function within the lymph nodes.     

Characterization of 17β-estradiol 3-(β-D-glucopyranoside) and 17-(α-D-glucopyranoside) as the metabolites of 17β-estradiol in the cultured ovaries of the silkworm,Bombyx mori

Summary The structures of the metabolites formed upon incubation of 17-estradiol with the ovaries of silkworm,Bombyx mori, have been determined as 17-estradiol 3-(-D-glucopyranoside) (1) and 17-(-D-glucopyranoside) (2) by spectroscopic means.     

Cys-tRNACys formation and cysteine biosynthesis in methanogenic archaea: two faces of the same problem?

Aminoacyl-tRNA (transfer RNA) synthetases are essential components of the cellular translation machinery as they provide the ribosome with aminoacyl-tRNAs. Aminoacyl-tRNA synthesis is generally well understood. However, the mechanism of Cys-tRNACys formation in three methanogenic archaea ( Methanocaldococcus jannaschii, Methanothermobacter thermautotrophicus and Methanopyrus kandleri) is still unknown, since no recognizable gene for a canonical cysteinyl-tRNA synthetase could be identified in the genome sequences of these organisms. Here we review the different routes recently proposed for Cys-tRNACys formation and discuss its possible link with cysteine biosynthesis in these methanogenic archaea.     

The rise of the tinplate industry.—V. Cockshutt on tinplate manufacture

Two laboratories which offered the new career of scientific work to women at the beginning of the twentieth century were the Biometric Laboratory and the Galton Eugenics Laboratory at University College London. The scientific careers of two women, Dr. Alice Lee (1859–1939) and Dr. Ethel Elderton (1878–1954), are examined. Intellectual and economic factors involved in the choice of a career in eugenics are described, together with some aspects of the relationship between eugenics and feminism.     

Histochemistry of 3β-hydroxysteroid dehydrogenase in monkey adrenal cortex

Zusammenfassung Es wird über mit Hydrocortisonacetat, ACTH und Aldosteronacetat induzierte morphologische und histochemische Veränderungen in der Nebennierenrinde desM. rhesus berichtet. Die bedeutende Verminderung der Steroid-3-ol-dehydrogenasischen Tätigkeit nach Cortisol und deren Zunahme nach ACTH wird hervorgehoben.     

The influence of N-methyl-N-β-chloroethyl hydrazines on the mitotic index of Ehrlich ascites tumor cells and the leukopoiesis of the mouse

Summary The cytostatic activity of N-methyl-N--chloroethylbenzaldehyd hydrazone, (B1) is at least equal to that of procarbazine when its effect is tested with the Ehrlich ascites tumor cells of the mouse and the Yoshida sarcoma of the rat. B1 causes a slighter decrease of mitotic cells and no shift from prophase to metaphase. These results suggest that the cytostatic effect of B1 is due to interference with cell metabolism or an effect at the cell membrane and not to an effect on cell proliferation. This assumption is supported by a considerable depression, of lymphocytes and a minor effect on granulopoiesis, which is especially sensitive towards proliferation toxins. All these findings suggest a different mechanism of action of B1 and procarbazine.