Spierule cells inDrosophila species

Summary Spherule cells are restricted to the larval stage and make up 5–16% of cells in the hemolymph. Their morphology varies between species, mainly due to the shape of their inclusions which may be oval (spheroidocytes), polyhedral (crystalloid cells), or clearly crystalline (crystal cells). These inclusions are very rich in tyrosine. They liquefy rapidly in vitro, whereby the cells become hyaline (coagulocytes).Acknowledgments. We thank Mr B. Barandun for excellent technical assistance. This investigation was supported by the Swiss National Science Foundation, grant No. 3.792.076.     

Blockade of ovulation in the rat initiated by an antimetabolite

Zusammenfassung Verabreichung von 3-Acetylpyridin zu bestimmten Zeiten der Pro-oestrus-Phase hemmt die Ovulation bei der Ratte. Dieser Hemmeffekt wird durch Pyridinnukleotide antagonisiert.

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Supported by grants from the Swiss Academy of Medical Sciences and the Hartmann-Müller Foundation, Zürich.     

Hundert Jahre Schweizer-Reagens

Summary Cuprammonia as a solvent for cellulose was discovered a hundred years ago byEduard Schweizer, Professor of Chemistry at the University of Zurich, and the heterogeneous swelling of plant fibres with this reagent was described in the same year byCarl Cramer, Professor of Botany at the Swiss Federal Institute of Technology then recently founded. Both discoveries were published in the Vierteljahrsschrift der Naturforschenden Gesellschaft Zürich 1857 and early 1858.     

The effect of splenectomy on the radiation disease of in utero irradiated foetus

Zusammenfassung Eine Splenektomie 2 h nach einer Ganzkörperbestrahlung von 250 R führt bei graviden Muttertieren zu keiner Verbesserung der fötalen überlebensrate. In Analogie zum recovery factor der gesunden Milz darf angenommen werden, dass sich in der bestrahlten Milz ein hochmolekularer, diaplazentar nicht diffusionsfähiger Stoff bildet.

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Acknowledgment: The author is indebted to M.Schäfer for her technical assistance.

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The experiments were supported by a grant from the Swiss National Fund.     

Different methotrexate effects in cultured normal and leukaemic human leukocytes

Summary Evidence is presented that the use of 2 different culture media, with or without methionine, can help to distinguish between normal and leukaemic methotrexate (MTX)-sensitive cells derived from chronic myeloid leukaemia patients. During the blast crisis MTX assays may help directly in the diagnostics of lymphoid involvement.This work was supported by the Polish Academy of Sciences within the project 09.7.4.1.4.Acknowledgments. We are indebted to Prof. Zofia Zieliska, Dept. of Cell Biochemistry, M. Nencki Institute of Experimental Biology PAN for providing the 5-methyltetrahydrofolate and for advice in these studies.     

Cytogenetic analysis of bone marrow cells and spermatogonia of male mice after in vivo treatment with arsenic

Summary Male Swiss Albino mice were injected i.p. with an As₂O₃ solution (0; 4; 8 and 12 mg As/kg) and sacrificed 12, 24, 36 and 48 h after injection. Neither chromatid nor chromosome aberrations were observed in bone marrow cells and spermatogonia.Acknowledgments. We thank Mr L. De Langhe for skillfull technical help. We acknowledge this work was supported by a grant of the Ministery of Public Health.     

On the regulation of lactate dehydrogenase isoenzyme concentrations in mammalian cells

Zusammenfassung Fritz et al.³ haben in Nature New Biol. 230, 119 ein Modell publiziert, mit dem sie die Regulation der intrazellulären LDH-Isoenzym-Konzentration erklären. Die vorliegende Arbeit zeigt, dass die Resultate vonFritz et al. einfacher durch Heterogenität der Zellen des untersuchten Gewebes erklärt werden kann als durch ihr Modell mit non-random association der LDH-Untereinheiten und verschiedenen turnover-Raten der Isoenzyme in derselben Zelle.

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I thank Drs.Ursprung, D. Turner, D. Seybold andH. Eppenberger for helpful discussions. This work was supported by the Swiss National Science Foundation, Project No. 3.247.69.     

Arousal-induced increase of cortical [K+] in unrestrained rats

Summary Changes of extracellular concentration of brain potassium [K⁺]_e were studied in lightly anesthetized unrestrained rats with ion-selective K⁺-microelectrodes introduced into the cerebral cortex with a head-mounted microdrive system. Nociceptive stimuli elicited EEG arousal lasting for 47 sec on the average which was accompanied by an increase of [K⁺]_e from 3.0 mM to 3.31 ± 0.04 mM.Acknowledgment. I wish to express my sincere gratitude to Dr. Bure from the Institute of Physiology, Czechoslovak Academy of Sciences, for his kind help in the preparation of this article.     

Coupling of fructose-1,6-P2 to aminated agarose by Schiff base reduction. Affinity chromatography of yeast aldolase

Summary Fructose-1,6-P₂ was immobilized by sodium borohydride reduction of the Schiff base formed with aminated agarose (AH-Sepharose 4B^®). The coupling occurs with high yield (25 moles immobilized fructose-1,6-P₂ per ml packed gel) at neutral pH and room temperature. Schiff base reduction thus provides a convenient and mild coupling procedure for sugar phosphates preserving their labile phospho ester bonds. As exemplified by a new isolation procedure for fructose-1,6-P₂ aldolase from yeast, sugar phosphates insolubilized in this manner may be used for affinity chromatography of the corresponding enzymes, provided that contaminating unspecific phosphatases are removed in a preceding fractionation step.This work was supported by the Swiss National Science Foundation, grant No. 3.620-0.75. A preliminary account has been presented at the 10th Int. Congress of Biochemistry, Hamburg, 1976, Abstracts. p. 194.Acknowledgment. The excellent technical assistance of Alice Gasser is gratefully acknowledged     

AnAnolis skin melanophore assay suitable for photoaffinity labeling studies with α-MSH

Summary Visual determination of MSH-induced pigment migration in melanophores of small pieces ofAnolis carolinensis skin is standardized by first measuring photoelectrometrically the change in reflection/transmission of the whole dorsal skin in response to different hormone concentrations. This method allows the rapid and precise recording of time-response curves after photoaffinity labeling of MSH receptors or of dose-response curves of large series of synthetic compounds.Acknowledgments. We wish to thank Ms V. Jäggin, Ms C. Schulthess and Ms G. van Hees for excellent technical assistance, Dr. R. Andreatta, Ciba-Geigy AG, Basel, for his generous gift of -MSH and Prof. A Pletscher for his continuous interest. This work was supported by the Swiss National Science Foundation.     

Regional cyclic AMP levels in homogenates of rat brain after ketalar and trifluoperazine

Summary There was a significant fall in cAMP levels after administration of TFP or ketalar. Different amounts of cAMP were present in different regions of rat brain. Concentrations of cAMP in different regions of the rat brain were found to decrease in the following order: cerebrum > thalamus with hypothalamus > midbrain > hippocampus > cerebral cortex.Conducted under ocntract No 10.4.2 with the Polish Academy of Science.     

Acid phosphatase activity of small intestine of mice after exposure to different doses of gamma rays

Summary Effect of whole-body radiation at 3 different dose levels on the activity of acid phosphatase was studied in the small intestine of Swiss albino mice. In all the 3 exposure groups the enzyme activity increased significantly at 24 h after irradiation; the time at which the maximum histological damage was seen. With the beginning of recovery the enzyme tended to decrease and gradually approached control values.     

Reappearance in vivo of neuraminidase-sensitive sialic acid in L 5222 rat leukemia cells

Summary Cell electrophoretic data and quantitative sialic acid determination show that, 16 to 20h after i.p. implantation of neuraminidase-treated L 5222 rat leukemia cells, the original sialic acid content at the cell periphery is reconstituted.This investigation was performed within the EORTIC Cell Surface Project Group and supported by the Swiss National Science Foundation, Grant No. 3.901.72, and by the Zürich Cancer League.     

Rate of oxidation and tissue concentrations of ethanol in mice

Résumé Chez la souris Swiss albinos le CEO est de 1578±209 mg/kg/h, après une injection de 10 g/kg d'éthanol. Les concentrations tissulaires sont de l'ordre de 4 à 6 g/kg. Les réductions des poids frais des organes ne sont pas significatifs.     

Autoradiographic analysis of FSH binding during follicular atresia

Binding of FSH to ovarian cells was studied in PMSG primed immature Swiss mice, 48 h after PMSG treatment, FSH-binding was higher in the periphery than in the cumulus cells of the antral follicles. Binding of FSH to granulosa cells of normal follicles was observed to be specific, 48 h after PMSG injection. No localization in the atretic follicles could be seen by autoradiography 72 h after priming.     

Announcement

Announcement

Announcement     

Protein structure and function

Posters

Protein structure and function     

Regulation of cell growth

Posters

Regulation of cell growth     

Effect of L-methionine-DL-sulphoximine on the photoproduction of hydrogen byRhodospirillum rubrum

Summary The repression of photoproduction of hydrogen by ammonia could be relieved by L-methionine-DL-sulfoximine. In the absence of ammonia, hydrogen evolution was inhibited by concentrations of L-methionine-DL-sulfoximine higher than 0.1 mM.Acknowledgments. This work was supported by the Swiss National Foundation for Scientific Research, grant 4.048.0.76.04, National Research Program Energy.     

Gene expression and replication

Posters

Gene expression and replication