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1.
Summary Classification of excitatory amino acids into different groups, of possible value for transmitter identification, can be made on the basis of the differential effects of altered external [Na+] and [K+] on motoneurone depolarization in frog and immature rat spinal cord.Acknowledgments. We thank Mr D. J. Oakes for skilled technical assistance. This work was supported from the Medical Research Council.  相似文献   

2.
Summary The digestive gland of the sea hare Aplysia limacina, collected in the bay of Naples, contains an array of polyhalogenated monoterpenes. The 2 major components are 3,4-erythro-7-dichloromethyl-3-methyl-3,4,8-trichloro-1,5 (E), 7 (Z)-octatriene (1), previously isolated from pacific red alga Plocamium cartilagineum, and the new 3,4-threo-7-dibromomethyl-3-methyl-3,4,8-trichloro-1,5 (E), 7 (E)-octatriene (2), whose structure has been assigned on the basis of analogy and of spectroscopic data. Examination of extracts of local red algae revealed that1 was present in Plocamium coccineum.Acknowledgments. We thank Dr D. J. Faulkner (University of California) for sending us the1H-NMR-spectra of a series of polyhalogenated monoterpenes, Dr F. Cinelli (Zoological Station) for identification of algae, and Mr A. Crispino (GC) and C. Di Pinto (NMR) for their technical assistance.  相似文献   

3.
Summary A 14-membered ring diterpenoid named cembrane, possessing Ca-antagonistic action on the isolated rabbit aorta, has been isolated from a soft coral of the genusSarcophyton, and its structure established by X-ray and spectroscopic data.The authors thank Mr. Z. Nagahama (Okinawa) for collection of soft corals, Miss R. Abe (the present institute) for her skillful assistance, and Dr. T. Higashijima, Prof. T. Miyazawa (Tokyo University), Mr. T. Hayase and Dr. H. Ohtani (Mitsubishi Chemical Industries Ltd) for1H and13C NMR-measurements.  相似文献   

4.
Summary By incubation of human erythrocyte ghosts with cholesterol oxidase (EC 1.1.3.6) part of the cholesterol of the membrane is replaced by 4-cholesten-3-one. This alteration in the sterol composition is accompanied by an inhibition of the (Na+, K+) ATPase of the erythrocyte membrane.Acknowledgments. This study was supported by the Deutsche Forschungsgemeinschaft Bonn-Bad Godesberg and the Sonderforschungsbereich 90 of the University of Heidelberg. We thank Mr.J. Schmidt and MissI. Geldmacher for skilful technical assistance.  相似文献   

5.
Summary Phosphocitrate and its analogue N-sulpho-2-amino tricarballylate were compared with ethane-1-hydroxy-1, 1-diphosphonate for inhibition of calcium phosphate crystallization in hydroxyapatite induced crystal growth and45Ca uptake by matrix vesicles. Phosphocitrate (1 M) was the most potent inhibitor followed by ethane-1-hydroxy-1, 1-diphosphonate and N-sulpho-2-amino tricarballylate, the latter requiring a high concentration (100 M) to be equally effective as an inhibitor.Acknowledgments. We wish to thank Mr J. Jordan and Miss L.C. Ward for the excellent technical assistance and Mr R.J. Tennant for the transmission electron microscopy. We also thank the Golden Poultry Farming Industries Ltd., Hobart, Tasmania for their generous supply of broiler strain chickens.  相似文献   

6.
Summary The possible effects of inhibition of the calcium-binding protein, calmodulin, on mammalian morphogenesis have been investigated by culturing rat embryos in vitro from 9 1/2 to 11 1/2 days of development in the presence of R24571 (calmidazolium), a specific inhibitor of calmoldulin. Embryos cultured in 10–2 mM R24571 for 48 h show inhibited development and exhibit a range of morphogenetic abnormalities including assymetry and neural tube defects. Embryos exposed to R24571 for the first 24 h of a 48 h culture are more severely affected than embryos exposed to R24571 for the last 24 h.Acknowledgments. We wish to thank Mr C. Veltkamp and Mr B. lewis for their expert help with the scanning electron microscopy and photography.  相似文献   

7.
Summary Using the micronucleus test as a screening method for mutagenic activity, no significant increase in the number of micronuclei was found when LSD, psilocybin or 9-THC were administered in 3 logarithmically increasing doses to mice. Azathioprine (Imuran®), given as a positive control, caused a statistically significant increase in micronucleated cells.Acknowledgment. The expert technical assistance of Mr Joop Branger is greatfully acknowledged. We thank Prof. Dr C. A. Salemink, University of Utrecht, for the supply of the THC, and Dr J. Fokkens, National Institute of Public Health, for preparing the solutions.  相似文献   

8.
Summary Active uptake of [32P]thiamine diphosphate byE. coli was analyzed using an improved method of gel filtration chromatography. The radioactive coenzyme was accumulated without dephosphorylation. From this result it was concluded that thiamine kinase is not involved in the membrane transport of thiamine inE. coli.We are indebted to Miss M. Abe for her technical assistance.  相似文献   

9.
Summary The specific binding activity to [14C]thiamine was found to be located in the plasma membrane ofSaccharomyces cerevisiae. The activity was inhibited by several thiamine analogs and it was hardly detectable in the plasma membrane from a thiamine transport mutant ofSaccharomyces cerevisiae. Some properties of the thiamine-binding activity of yeast plasma membrane are discussed in connection with those of the thiamine transport system.  相似文献   

10.
Summary Hydrostatic pressure applied to isolated eel gills induces changes in the tissue, Na+, K+ and Cl contents. It also inhibits the activity of the (Na++K+) ATPase. Results are discussed in terms of an effect of pressure on the Na+ and Cl pumps and on the passive permeability processes.A. P., Chargé de Recherches du F. N. R. S.; R. G., Chercheur qualifié du F. N. R. S., We are grateful to Prof. A. Distèche and E. Schoffeniels for their advice throughout this work. We also want to thank Mr J. M. Theate and Mrs C. Marchand-Coquay for their valuable technical assistance.  相似文献   

11.
Summary The volume regulation process at work in rabbit kidney cortex slices submitted to hypo-osmotic media show both a swelling limitation and a volume readjustment phase. Swelling limitation is Na+ dependent and is blocked by ouabain 10–3 M. There is, however, no need to implicate the activity of a ouabain sensitive Na+/K+ pump in this process.This work has been aided by a grant 1.5.422.82F from the FNRS to R.G. We wish to thank Mr J.M. Theate for his skilful assitance.  相似文献   

12.
Summary The attraction ofS. scolytus to the components of Multilure is described. 4-Methyl-3-heptanol is an attractant which is synergised bya-cubebene. Multistriatin appears to be an inhibitor. A combination of 4-methyl-3-heptanol and cubeb oil is more effective as a bait forS. scolytus than Multilure.We thank Mr A. K. Hughes and Mr J. Boswell for their cooperation in allowing us to conduct experiments on Parham Estate; Mr D. Mobbs and Mr C. Thorne for the statistical analyses; Dr J. W. Peacock for samples of mixed isomers of multistriatin and distilled cubeb oil; Mrs J. Allsop and Mr N. J. Fielding for technical assistance. We are grateful to Mr D. Bevan, Dr J. H. Borden, Dr J. F. Grove and Prof. A. W. Johnson for their interest and encouragement.  相似文献   

13.
Summary Cortisol induces a migration of eosinophil leukocytes from the blood to several lymphoid organs, such as the spleen, lymph nodes and thymus, but not to other tissues. This migration explains the cortisol-induced blood eosinopenia, which is much more pronounced in intact than in splenectomized animals.Acknowledgments. This work was supported by the Servicio de Desarrollo Cientifico y Creación Artística from the University of Chile. Hydrocortisone sodium succinate (Solu-Cortef®, Upjohn) was kindly provided by Upjohn Co., Santiago, Chile. We appreciate the technical assistence from Dr E. del Solar, Mr D. Sáez, Miss J. Habach, Mr M. López and Miss M. Liendo.  相似文献   

14.
    
Summary The isolation and structure determination of 9(15)-africanene (1) from the soft coralSinularia polydactyla is described.For part XXXVII, see: J. C. Braekman, D. Daloze, G. Hulot, B. Tursch, J. P. Declercq, G. Germain and M. Van Meerssche, Bull. Soc. Chim. Belg.87, 917 (1978).King Leopold III Biological Station (Laing Island, Papua-New Guinea): Contribution No. 15.Acknowledgment. We thank Prof. Y. Kashman for sending us preliminary information on his work and for a sample of the ketone. We thank also Dr Verseveldt for the identification of the animal, Mr J. Pierret for his participation in its collection and Dr G. Aranda for the CD measurement. We gratefully acknowledge the help of the FRFC for the purchase of the diffractometer.  相似文献   

15.
Summary Males ofPodisus fretus (Hemiptera: Pentatomidae) release a long-range attractant pheromone containing linalool (49.0%), (E)-2-hexenal (34.5%), benzyl alcohol (12.0%), nerolidol (2.0%),-terpineol (1.1%), and traces of several other compounds. The eastern yellowjacket,Vespula maculifrons (Hymenoptera: Vespidae), is attracted to artificial pheromones forP. fretus and for the sympatric species,Podisus maculiventris.The authors thank Mr T.J. Henry of the USDA Systematic Entomology Laboratory and Dr J.E. McPherson, Southern Illinois University, for examining the pentatomid species and Dr A.S. Menke, USDA-SEL, for determining the yellowjacket species. We also thank S. Wilzer for technical assistance. Mention of a company name does not imply endorsement by the US Department of Agriculture.  相似文献   

16.
Summary Corpora allata fromOncopeltus fasciatus incubated in vitro in medium containing 10–5.35 M (1 g/ml) of precocene II lose their ability to secrete juvenile hormone when reimplanted into last instar larvae.Acknowledgments. We thank Mr K. Dorn, Mrs L. Dolezal, Mrs V. Nötzli-Graf, Mr K.H. Trautmann and Mr A. Schuler for technical help, Dr W. Vogel and Dr A. Dübendorfer for valuable discussions.  相似文献   

17.
Summary Awake, freely breathing rats subjected to moderate hypoxia (10% O2) manifest prompt tachycardia which is essentially unaffected by atropine and is blocked by propranolol, and is thus apparently mainly of sympathetic origin.This work was supported by grants from American Heart Association — Greater Los Angeles Affiliate (437IG), and National Science Foundation (GB-41390). J. D. L. was a Summer Scholar selected by the Committee for Advance Science Training. We thank Mr D. Ward and Miss L. J. Berg for much valuable assistance and Dr. J. L. Kinney for help in the statistical analysis of the data.  相似文献   

18.
Zusammenfassung Chemisch dissoziierte Zellen des KieselschwammesGeodia cydonium reaggregieren aufgrund zweier verschiedenr Reaggregationsprinzipien. Der Aggnegationsfaktor, auf den die Primäraggregation zurückgeht, ist membrangebunden und wird durch Proteasen nicht inaktiviert. Der sekundäre Aggregationsfaktor wurde 500fach angereichert. Das Molekulargewicht dieses Aggregationsfaktors beträgt etwa 20000 Daltons; er ist mit einem ringförmigen Makromolekül (2×109 Daltons) assoziiert.

Acknowledgments. We wish to thank Mrs.V. Pondeljak, Mrs.U. Müller-Berger, Mr. R. Beyer andMr. M. Srecec for their excellent technical assistance. We gratefully acknowledge the advice of dipl. Chem.J. Obermeier for the carbodiimide coupling method. This work is supported by Fonds der Chemischen Industrie and by the Landesversicherungsantalt Rheinland-Pfalz, Speyer/Rh.  相似文献   

19.
Summary 2 yellow naphthoquinone derivatives were isolated from several pathogenic strains ofHendersonula toruloidea Nattrass. They were identified as 2,7-dimethoxy-6-ethyl-5-hydroxy-1,4-naphthoquinone and 2,7-dimethoxy-5-hydroxy-6-(1-acetoxyethyl)-1,4-naphthoquinone by means of physico-chemical methods.Thanks are due to Mr A.J.M. van Beijnen, Laboratory for Organic Chemistry, State University of Utrecht, for optical rotation measurements.The authors are indebted to Mr C. Versluys, Analytical Laboratory, State University of Utrecht, for measuring the mass spectra.We thank Mr J. W. Marsman, Institute for Organic Chemistry TNO, Utrecht, for the PMR-spectra.  相似文献   

20.
Résumé Un état d'insuffisance placentaire a été produit chez la ratte au moyen de lésions électrolytiques effectuées au 17e jour de gestation. Le poids corporel ainsi que le poids du foie des foetus, au 21e jour de la grossesse, présentèrent une diminution; tandis que le poids du cerveau en relation à celui du foie avait augmenté. Ces résultats indiquent que les foetus ainsi traités subissent un retardement de croissance par rapport aux témoins de même âge.

Acknowledgments. The author wishes to thank Dr.D. G. Montemurro for the use of the electrolytic apparatus and Mr.N. Falconer and Mr.J. Krcek for their technical assistance.  相似文献   

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