Role of neurotransmitter release and cyclic AMP-dependent membrane phosphorylation in low voltage myocardial automaticity

Summary Low voltage myocardial automaticity (LVA) was investigated by pharmacological modulations of the presynaptic and postsynaptic processes. The sensitivity of LVA both to inhibitor and stimulator of neutrotransmitter release suggests its involvement in LVA genesis. Moreover, LVA is blocked by the inhibition of the cyclic AMP system, supporting the participation of the c-AMP-dependent membrane phosphorylation in calcium-mediated cardiac electrogenesis.Acknowledgment. The generous gift of RM1 12330A from Prof. G. Guellen, Paris, and of tolbutamide from Prof. T. Hayakawa, Tokyo, are gratefully acknowledged.     

Retinol: Predominant form of vitamin A in corpus luteum

Summary We could not confirm the results of a previous research group^2,3 which stated that retinal (vitamin A aldehyde) is present in corpus luteum of bovine origin. On the contrary we establish the occurrence of retinol (vitamin A alcohol) in both human and bovine corpora lutea. Identity of the compound is confirmed by its chromatographic behavior on high performance liquid chromatographic systems (adsorption and reversed phase) and by spectrometric analysis (UV, fluorimetry).Acknowledgments. The authors are indebted to Prof. D. Vandekerckhove and Prof. F. Derom, University of Gent, Faculty of Medecine, for supplying human corpora lutea.     

C-band positive W chromosome in the female Indian frog

Summary In the female Indian frog,Rana tigrina (2n=26; NF=52), the female is heterogametic. The heterochromosomes (ZW) are morphologically indistinguishable, but the W chromosome proves by C-banding analysis to be entierly heterochromatic.Acknowledgment. S.C. is grateful to Prof. G.K. Manna, Zoology Department, Kalyani University, Prof. Archana Sharma, Botany Department, Calcutta University and to Prof. T. Sharma, Zoology Department, Banarus Hindu University for encouragements. He is also thankful to Prof. D.K. Choudhuri, Burdwan University for support.     

Some observations on the effect of Ro 7-1051 on Trypanosoma cruzi,particularly in cell culture

Summary The drug Ro 7-1051 showed a deleterious effect on the intracellular and extracellular forms of Trypanosoma cruzi represented by nuclear pyknosis, fragmentation and lysis of parasites and by its reduced susceptibility to infection.Acknowledgments. The authors are deeply thankful to Roche Products for supplying the drug and for valuable information. The authors are also grateful to Prof. Nelson Villa for criticism and to Miss edna Bertin for technical assistance     

Untersuchungen über die Wirkung von Kinetin auf Kallus und Tumoren bei Organkulturen vonNicotiana glauca,N. langsdorffii und deren amphidiploiden Bastard

Summary In leaf cultures ofNicotiana glauca, N. langsdorffii, and their amphidiploid hybrid, callus growth or tumor formation is enhanced by kinetin, depending on its concentration. Of the 2 species and their hybrid, maximum response was found in the hybrid, less inN. glauca, the slightest response being found inN. langsdorffii. These facts confirm the earlier finding of a connection between callus-forming potency inN. glauca and tumor formation in its hybrid.

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Den Herren Prof. Dr.G. de Lattin (Zoologisches Institut der Universität des Saarlandes) und Prof. Dr.F. Anders (Genetisches Institut der Justus Liebig-Universität, Giessen) bin ich für die Förderung dieser Arbeit zu grösstem Dank verpflichtet.     

Formation of carthamin by a partially purified enzyme from safflower seedlings

Summary An enzyme responsible for synthesizing carthamin from precarthamin was partially purified and the catalytic properties were investigated.Acknowledgments. The authors wish to thank Prof. A. Komamine, University of Tokyo, for reading this paper. We are indebted to Prof. A. Saito, Tokai University, for performing emission spectrochemical analysis of the enzyme protein used in this study.     

A new,unexpected marine source of a molting hormone. Isolation of ecdysterone in large amounts from the zoanthidGerardia savaglia

Summary Ecdysterone was found in large amounts in the Mediterranean zoanthidGerardia savaglia both immediately after its collection and after it had been kept for 15 months in an aquarium. This is the first time that an ecdysteroid has been found in a marine animal which does not belong to the phylum Arthropoda.Acknowledgments. We are grateful to Dr E. Volpi, Trento, for collecting, and keeping alive, the zoanthid, and to Prof. L. Rossi, Torino, both for the identification and for useful comments, and to Prof. L. Colombo, Padova, for stimulating discussions. This work was funded by the Provincia Autonoma di Trento, Assessorato Agricoltura e Foreste, within our program for biological control of phytopathogenic fungi, by C.N.R., Roma, and by M.P.I., through the Centro Interuniversitario di Biologia Marina in Livorno.Laboratorio di Chimica.Stazione Sperimentale Agraria.To whom reprint requests should be addressed.     

Mechanism of teratogenic action of hypoglycin-A

Zusammenfassung Simultane Verabreichung von Riboflavin und Hypoglycin-A reduzierte das Auftreten von foetalen Missbildungen in Ratten. Dagegen haben Carnitin und Leucin keinen Einfluss auf die teratogene Wirkung des Hypoglycins.

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I thank Prof.D. A. N. Hoyte and Prof.B. N. Kropp for helpful discussions, and Prof.C. von Holt for a generous supply of hypoglycin-A.     

Anomalous stability of insulin at very high pressure

Summary Insulin is unaffected by pressures of 48,000 b in the solid state at room temperature, as elucidated both by spectroscopic measurements and bioassay. Its compression curve is reversible. The presence of water does not alter this property. Of a number of other proteins investigated insulin appears to be unique with regard to its pressure stability. The relative rigidity of the molecule combined with its small size may account for some of these properties.Acknowlegments. I should like to thank Prof. Willard F. Libby of the Department of Chemistry and Institute of Geophysics of the University of California, Los Angeles, for his interest and support of this study.     

Honey-induced pollen embryogenesis in anther cultures ofDatura metel

Summary In anther cultures ofDatura metel, pollen-embryoids could be induced on a medium consisting of honey alone. Further studies revealed that a combination of fructose and dextrose was sufficient to trigger pollen-embryogenesis. The 2 sugars, when tried individually, did not elicit any response.The authors wish to thank Prof. V.L. Chopra and Prof. S. Ramanujam for their help and encouragement.     

Search for sex-dependent and gestation-induced changes in choline and ethanolamine phosphorylating activities

Summary Choline kinase and ethanolamine kinase of liver, brain and kidney had nearly the same activity in 4-monthold male and virgin female mice. Ethanolamine kinase activity was almost doubled in the liver and brain of mice in advanced pregnancy compared with the virgin, while choline kinase activity was unaltered.Acknowledgment. The author records his sincere thanks to Prof. P. S. Krishnan and Prof. G. G. Sanwal for their valuable suggestions.     

Correlations between the neurobiology of colour vision and the psycholinguistics of colour naming

Summary Neurobiological experiments demonstrate that colour sensation is perceived by the brain by processes which, in principle, follow the opponent colour pairs scheme proposed by Hering in 1874. Tests on colour naming in various European, Asian and Central American languages have shown that the opponent scheme is also reflected in psycholinguistics. The linguistic evolution of colour terms proposed by Berlin and Kay (1969) is correlated directly with the ontogenetic development of language in children as elucidated by Jakobson (1941). Colour vision is therefore a suitable field for interdisciplinary investigations of brain processes and linguistics.Dedicated to Prof. Roman Jakobson, Cambridge, Mass.Acknowledgment. I thank Prof. Roman Jakobson, Harvard University and M.I.T., Cambridge (Mass.) and Prof. Elmar Holenstein, Ruhr-Universität, Bochum, Germany (formerly University of Zurich, Switzerland) for many stimulating discussions.     

Absorption of glycine,L-alanine and L-phenylalanine in the midgut of the larvae ofBombyx mori

Summary A net absorption of glycine, L-alanine and L-phenylalanine occurs across the isolated midgut of the larvae ofBombyx mori. Although glycine and L-phenylalanine are not metabolized, L-alanine is converted by the midgut and has a metabolic effect on the transepithelial electrical potential difference of the tissue.Acknowledgments. We are very much indebted to Prof. V. Capraro for helpful advice and criticism. We are also grateful to Prof. G. Reali for his interest and support of this research.     

A new selective insecticidal uncoupler of oxidative phosphorylation

Summary A new aryl hydrazone structure with high insecticidal activity against the Australian sheep blowfly,Lucilia cuprina, was shown to have a higher activity as an uncoupler of oxidative phosphorylation in insect compared to mammalian mitochondrial preparations. This compound possesses the requirements of other uncouplers in its measured pKa and lipid solubility. However, when compared to a closely related structure with similar physicochemical properties, its insecticidal and insect mitochondrial uncoupling activities are greater and it exhibits decreased mammalian toxicity corresponding to this differential biochemical selectivity.Acknowledgment. We thank Mr K. Rihs for preparation of the hydrazones and Prof. Dr K.H. Büchel for supply of hydrazone III.     

Presence of intrachromatidic bands in mitotic chromosomes ofTriturus marmoratus (Amphibia: Caudata)

Summary The C-banding technique has revealed the existence of single and double intrachromatidic bands in mitotic chromosomes ofTriturus marmoratus. The presence of the bands is discussed on the basis of the helical coil model versus the radial loop model, which assumes a different packing of the DNA fiber.We are very indebted to Prof. C. García de la Vega for his indispensable help, to Prof. Dr J. Martín for his comments and to M. Herrero for his support.     

Central course of photic input in the ventral nerve cord of scorpion (Heterometrus fulvipes)

Summary The course of the photic input from the metasoma in the ventral nerve cord of scorpion was studied. The input was found to influence the activity in a large number of neurons in the nerve cord. The phenomenon of contralateral stimulation of units at various levels of the nerve cord has heen demonstrated.Acknowledgments. The electronic equipment used for the study was obtained with the help of Prof.T. H. Bullock and the late Prof.K. Pampapathi Rao who initiated me into this field of study, through a research grant from the USAFOSR to them. I am highly grateful to Prof.Bullock for permitting me to use the equipment. I am also grateful to Dr.A. R. Kasturi Bai for her kind encouragement and Dr.S. A. T. Venkatachari for his helpful comments.     

Current(I)-voltage(V) relationships of the neuromembrane of an identifiable giant neurone of an Afican giant snail (Achatina fulica Férussac) in the presence of an inhibitory tripeptide,L-Lys-L-Phe-L-Tyr

Summary An inhibitory tripeptide, L-Lys-L-Phe-L-Tyr, caused membrane hyperpolarization of the TAN (tonically autoactive neurone) resulting in an elevated firing level. The tripeptide, however, did not markedly affect either the TAN I–V curve or the firing pattern obtained by transmembrane triangular current injection.The authors wish to express their thanks to Prof. M. Kohsaka and Prof. A. Mori of Okayama University for the helpful advice, and to Dr A. Inoue of Daiichi Pharmaceutical Co. for the donation of L-Lys-L-Phe-L-Tyr.     

Arrest of somatic cells at G2 by Sevin (pesticide)

Summary The treatment of onion root meristems with the pesticide Sevin [carbaryl (1-naphthyl n-methyl carbamate)] induces an accumulation of interphase nuclei with a larger diameter, and a subsequent decrease in the index of smaller nuclei. It is concluded that Sevin depresses mitosis by arresting cells at G₂ without affecting DNA synthesis.The authors are grateful to Prof. K. S. Bilgrami, Head of the Postgraduate Department of Botany, Bhagalpur University, for providing facilities and to Prof. B.N. Mookerjee for his valued suggestions.     

The synthesis of total and specific glycosaminoglycans during development of experimental liver cirrhosis

Summary During hepatic fibrogenesis induced by long-term administration of thioacetamide, the synthsis of chondroitin 4,6-sulfate and hyaluronic acid was strongly enhanced; the formation of heparan sulfate comprising at least 70% of total liver GAG synthesis and of a keratan-sulfate-like fraction was stimulated 1.7fold. Formation of dermatan-sulfate in liver could not be detected.We are grateful to Prof. W. Kühnel, Department of Anatomy, and to Prof. R. Lindenfelser, Department of Pathology, RWTH Aachen, for critical examination of the histology.