Activity of orotate metabolizing enzyme complex and various urea-cycle enzymes in mutant mice with ornithine transcarbamylase deficiency

Summary The overall activity of the enzyme complex consisting of orotate phosphoribosyl transferase and orotidine monophosphate decarboxylase, and of various enzymes of the urea cycle, has been studied in sparse-fur (spf) mutant mice with ornithine transcarbamylase deficiency. The enzyme complex has a lower overall activity, which could be caused by disturbed pyrimidine metabolism due to hyperammonemia. Other enzymes of the urea cycle do not show any significant change.Acknowledgments. The research was supported by a grant from the Conseil des Clubs Sociaux and Fondation Justine Lacoste Beaubien, Montréal. The authors wish to thank Ms Louise Poulin and Ms Francine Poisson for technical assistance.     

Symbioramide,a novel Ca2+-ATPase activator from the cultured dinoflagellateSymbiodinium sp.

Summary A novel sphingosine derivative, symbioramide, has been isolated from the laboratory-cultured dinoflagellateSymbiodinium sp. as a sarcoplasmic reticulum (SR) Ca²⁺-ATPase activator, and its structure elucidated to be1 on the basis of spectral and chemical means.Acknowledgments. We thank Ms M. Hamashima and Ms A. Muroyama for their technical assistance.     

Plakorin,a potent Ca2+-ATPase activator from the Okinawan marine spongePlakortis sp.

Summary A new cyclic peroxide, plakorin, which is a potent sarcoplasmic reticulum (SR) Ca^a+-ATPase activator has been isolated from the Okinawan marine spongePlakortis sp., its structure was elucidated on the basis of spectral data.Acknowledgments. We thank Ms M. Hamashima and Ms A. Muroyama for their technical assistance.     

The application of sodium deoxycholate and Sephacryl-200 for the delipidation and separation of high density lipoprotein

Summary A method to remove lipids from human plasma high-density lipoprotein (HDL) was developed. The procedure required column chromatography on Sephacryl-200 in the presence of the bile salt sodium deoxycholate. The lipid free protein obtained retained the immunological properties of the native HDL.The author is grateful to Ms L. Gray for her excellent technical assistance and Dr M. Fainaru of the Hadassah Medical Organization, Jerusalem, and Dr C. Heuck of the Klinisches Institut für Herzinfarktoforschung of Heidelberg, for kindly supplying purified apo-A, apo-A antiserum and apo-B antiserum.     

Ecdysteroid-dependent larval-adult oviduct transformation in the milkweed bugOncopeltus fasciatus requires absence of juvenile hormone

Summary It has been tested whether juvenile hormone plays a role in the larval-adult transformation of lateral oviducts in the milkweed bug. The transformation is ecdysteroid-dependent, as was reported previously². Application of precocene or juvenile hormone III proved that the absence of juvenile hormone is required.Acknowledgments. This work was supported by a grant (Do 163/91) of the DFG. We thank Ms C. Friederichs for excellent technical support.     

Electro-mechanical noise in atrial muscle fibres of the carp

Summary Steady membrane voltage fluctuations have been observed in atrial muscle fibres of the carp. These voltage fluctuations produce minute mechanical oscillations, as revealed by an interference contrast microscope. The steady voltage fluctuations may be related to abnormal automaticity in the heart.Supported by the U.S. Israel Binational Science Foundation, Jerusalem, and is part of a thesis to be submitted by Ms Akselrod to the Tel-Aviv University. We thank Ms M. Bendikowski for her efficient technical assistance.     

Effects of cadmium on the immune system of mice

Summary Chronic oral exposure of mice to Cd⁺⁺ inhibits cell-mediated immunity of delayed type hypersensitivity induced by sheep red blood cells (SRBC). No effect was detected on humoral immune response to SRBC. Spleen cells derived from mice exposed to Cd⁺⁺ showed in vitro enhanced response to T and B cell mitogens. These results demonstrate that Cd⁺⁺ exposure alters the immune system of mice.Dedicated to Prof. Georg Henneberg on the occasion of his 70th anniversary on 12.10.1978.Acknowledgments. Supported by a grant from the Umweltbundesamt. We thank Ms Odenwald, Ms Schulz, Klinikum Steglitz, and Ms Emeis, Robert Koch-Institut Abt. Immunologie, for the excellent technical assistance.     

A potent actomyosin ATPase activator from the Okinawan marine spongeAgelas cf.nemoechinata

Summary A bromine-containing alkaloid, oxysceptrin, has been isolated as a potent actomyosin ATPase activator from the Okinawan marine spongeAgelas cf.nemoechinata, and the structure elucidated to be1 on the basis of the 2D NMR spectral data.Acknowledgments. We thank Mr Z. Nagahama for his help in sponge collecting and Ms M. Takamatsu for her technical assistance.     

Spectral properties of methemoglobins prepared by the action of sodium nitrite and potassium ferricyanide

Summary Methemoglobin was prepared by the addition of sodium nitrite or potassium ferricyanide to oxy or deoxyhemoglobin. The spectral properties of these methemoglobins were studied before and after extensive dialysis. It is shown that the methemoglobin formed by sodium nitrite has substantial spectral differences in visible and Soret band compared to that formed by potassium ferricyanide. These differences are proportional to the excess of sodium nitrite only. This suggests that both methemoglobins are similar compounds.Supported by NIH grant No. 5R01AM 20181-03 and VA grant No. 5455-003.Acknowledgments. The technical assistance of Ms Carol A. Perry and the secretarial assistance of Ms Wanda Stewart are highly appreciated.     

Estrogens in insects

Summary Insects representing 5 different orders contain androgen and estrogen-like substances as determined by radioimmunoassay. Estradiol and estriol have been identified by gas chromatography-mass spectrometry. The presence of these steroids in insects suggests that the vertebrate sex hormones have an ancient evolutionary history.We thank Ms Mary Ann Seifert of the Campus Chemical Instrumentation Center of The Ohio State University, Mr John Powell of the Department of Obstetrics and Gynecology, Ms Florence Kraft and Mr Charles Palmer Jr for their technical assistance.From September 1982 to August 1983, Dr Mechoulam was Distinguished Visiting Professor of the Ohio State University, supported in part by the Graduate School.     

Comparison of the effects of different isomers of bicuculline infused in the preoptic area on male rat sexual behavior

Summary Intracerebral infusion of (+) bicuculline methiodide, but not of its (–) isomer, in the preoptic area, stimulated masculine sexual behavior in rat as evidenced by a decrease in the number of intromissions preceding ejaculation and a shortening of the ejaculation latency and postejaculatory interval. Data suggest a role of the GABAergic system in mediating masculine sexual behavior.Acknowledgments. Authors wish to thank Ms Elisabeth Wallin for excellent technical assistance and Ms Madelene Kröning for preparing the figures.     

A simple system for mechanical and electrical recordings from frog nerve-muscle preparation

Summary A device is described which can be used for simultaneous measurement of the muscle action potential and the contraction of the frog gastrocnemius nerve-muscle preparation. The apparatus is characterized by ease of construction, good accuracy and reliability.We thank Ms.C. Friedemann for preparation of the drawings; Ms.A. Middelmann for technical assistance.     

Captopril (SQ 14,225): In vitro and in vivo influence on the proliferative response of rat lymphocytes

Summary Captopril in vitro (50–500 g/ml) increased³H-TdR incorporation in unstimulated and mitogen-stimulated cultures of rat lymphocytes. Unseparated spleen and lymph node cells of rats orally treated with captopril (50 mg/kg/day×4) showed decreased basal and mitogen stimulated³H-TdR incorporation. The removal of macrophages abrogated this inhibitory effect. Leucine aminopeptidase activity of macrophages was reduced — in vivo and in vitro — by captopril.Acknowledgments. The authors thank the Squibb Institute for Medical Research for the gift of Captopril. The excellent technical assistance of Ms B. Hasselriis, Ms B. Rumler and Ms E. Greve Petersen is gratefully acknowledged.     

Genes regulating the appearance of two kinds of fruit inMicroseris strain B87 (Asteraceae:Compositae)

Summary The annual hybrid strainMicroseris B87 (M. pygmaea x M. bigelovii) produces 2 kinds of fruit (achenes) on its flowering heads, outer hairy and inner smooth ones. 2 unlinked genes are identified that determine the relative number of hairy achenes, on a logarithmic scale.Supported by grants Ba 536/1-6 from the Deutsche Forschungsgemeinschaft, and DEB-780940 from the National Science Foundation.We thank Ms. E. Oeldorf and particularly Ms. A. König for technical assistance.     

Synthesis,crystallization and properties of acetyl phenylalanyl lysine chloromethyl ketone: A potential inhibitor of serine proteases

Summary A procedure for the synthesis of acetyl phenylalanyl lysine chloromethyl ketone is described. The chloromethyl ketone derivative is a noncompetitive inhibitor of trypsin (K₁=5.9×10^–3 M).Acknowledgments. The authors are grateful to Dr Arthur L. Bacon for his constant support and encouragement. Special thanks are due to Dr William Kray for initiating this research project. We thank Mrs Juliette Barclay, Ms Earlene Spratling and Ms Ollivette Hill for their technical assistance in conducting some of the experiments. This investigation was supported by MBS grant RR8105 from the General Research Support Branch, Division of Research Resources, National Institutes of Health.     

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.     

Antifertility activity of trimethylphosphate in male rats

Summary The toxic effect of trimethylphosphate on rat testes was investigated after oral dosing with 250 mg/kg for either 5 days/week for 30 days or 6 days/week for 60 days. After these prolonged treatments azoospermia resulted.Acknowledgments. The authors wish to thank Ms M. Michelles, Ms A. Murray and Ms R. Peake for their technical support.     

Peritoneal macrophages from adjuvant arthritic rats enhance tumour cell growth in vitro

Summary Peritoneal macrophages from rats with adjuvant arthritis enhance the incorporation of³H-thymidine in 2 tumour cell lines in vitro. Maximal enhancement is found during the development of the secondary lesions, and it is suggested that the immunologic commitment of the macrophages could interfere with their regulation of tumour cell proliferation in vivo.Acknowledgments. The authors thank Drs P.F. Engel and M.P. Andreasen from the Finsen Institute, Copenhagen, for their gift of tumour cells and Ms E. Greve Petersen, Ms B. Hasselriis and Ms F. Norris for excellent technical assistance.     

Attempt to alter antigenic structure of normal tissues by treatment with dimethyl-triazeno-imidazole-carboxamide in vivo

Summary The antigenic structure of normal skin and spleen cells has been investigated following in vivo treatment with the compound DIC. In experiments involving skin grafting in the normal and sensitized host, cross sensitization with a DIC-antigenic lymphoma and³H-thymidine incorporation by lymphocytes cultured with DIC-treated spleen cells, new antigens on DIC-treated tissues were not demonstrated.Research supported in part by Contract No. 74.00237.04 from C.N.R., Rome.We wish to thank Mr.C. R. Reeder of the Mammalian Genetics and Animal Production Section of NCI, NIH, Bethesda, Maryland, USA, for breeding and providing the animals, and Serpero Foundation, Milan, for support. The proficient technical assistance of Ms.C. Cattoi andD. Peroni is also acknowledged.     

FITC-dextrans as fluorescence and electron microscopic tracers in studies on capillary and cell permeability of the CNS

Summary FITC-dextrans can be detected at the ultrastructural level as round electron dense particles, with no sign of distortion or aggregation. Because this tracer is a stable, non-toxic polymer of biological origin obtainable in a wide range of molecular weights, it may be useful for further studies of tissue permeability.The author is grateful to Ms. H. Büscher and Ms. S. Klemt, Department of Pathology, for their excellent technical assistance.