Presynaptic effect of the neuro-muscular transmitter

Zusammenfassung Nach transversaler Durchschneidung der Muskelfasern des isolierten Rattenzwerchfelles auf jeder Seite der Endplattenregion wurde die elektrische Aktivität im stimulierten Nervus phrenicus nach Zusatz von Prostigmin, DFP und zum Teil auch Acetylcholin studiert. Die orthodromen Nervenimpulse wurden von antidromer Aktivität im Nerv gefolgt, auch dann, wenn durch Demarkationsvorgänge das Ruhepotential des Muskels bis auf 20 mV heruntergebracht und die elektrische Aktivität im Muskel gelöscht war. Dies scheint für eine praesynaptische Wirkung des Acetylcholins zu sprechen.     

Über Struktur und Aktivität der den H2O2-Zerfall katalysierenden Cu2+-Komplexe. — VI. Differenzierung von nativer RNS und nativer DNS bzw. denaturierter DNS auf Grund der katalytischen Eigenschaften

Summary The catalysis of H₂O₂ decomposition by Cu²⁺-complexes of RNA and DNA has been investigated. It is shown that both complexes decompose H₂O₂, but only the Cu²⁺-RNA-system shows peroxidative activity too, e.g. only in this case the nucleotide bases are degraded. Thermal denaturation of DNA also leads to a Cu²⁺-complex with peroxidative activity, the latter being dependent on the degree of denaturation.

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V. Mitteilung:S. Petri, H. Sigel undH. Erlenmeyer, Helv. chim. Acta49, 1778 (1966).

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12. Mitteilung überMetallionen und H ₂ O ₂; 11. Mitteilung:H. Ch. Curtius, P. Anders, R. Zell, H. Sigel undH. Erlenmeyer, Helv. chim. Acta49, 2256 (1966).     

Notes on toxinology

Conclusions Some of the papers to follow in the present series of communications on toxinology will show that in the field of chemistry, physiology, pharmacology and immunology, as well as molecular biology, animal venoms provide us with some particularly useful models. Obviously, this is one of the main reasons for the growing interest shown by numerous scientists in animal toxins.With reference to medicine, more research is needed in the field just mentioned with the aim of improving medical care. In addition, however, it is postulated that research on the behaviour of venomous animals towards man, and research into the quantities of venom actually applied to man, be intensified. Also, on the basis of results in this context, people most exposed could be provided with more and better information about prevention.Work of this sort requests the collaboration of biologists, who observe toxic animals in their natural habitat and who investigate in particular when, and under what prerogatives, the animals make use of toxins in their natural surroundings. Thus we end up with what has been said in the introduction to these notes: toxic animals are to be studied as entities and toxicity has to be looked at from all aspects essential for life, possibly including parasite and population control.Should the very last point prove valid, fascinating links could be established between toxinology and ecology and in turn migt become important for nature conservation. Thus, toxinology is but a budding field, the limits of which, can yet only be assumed.     

Concerning the free amino acids in the hydroid tubularia

Résumé La composition de l'amine acide libre dans les deux espèces deTubularia a été examinée au moyen de la chromatographie. Les tissus d'hydranthe deT. crocea avaient 21 amines acides libres dont 18 ont été identifiées dans les hydrocauli et dans les hydranthes régénérés deT. crocea, 19 dans les hydranthes deT. spectabilis et 14 dans les hydrocauli deT. spectabilis. La différence principale entre les hydranthes et les hydrocauli réside dans la distribution de certaines taches non-identifiées qui apparurent dans les chromatogrammes developpés avec la ninhydrine et les réactifs pour les groupes des imidazoles, guanidines, ou sulfhydriles.

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Part of a dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy, Florida State University. Aided by a National Science Foundation Predoctoral Fellowship and a National Science Foundation Grant to Dr. C. B.Metz, Contribution number 122 from the Oceanographic Institute, Florida State University.     

Statistical analysis of the relation between the length of the genoma and the diploid number of the chromosomes inCercopithecus

Riassunto Utilizzando metodiche statistiche è stato analizzato l'incremento della lunghezza totale del genoma rispetto al numero dei cromosomi in piastre a diversa ploidia nel genereCercopithecus. È stato riscontrato che la relazione numero dei cromosomi e lunghezza del genoma è significativamente lineare. È supposto un meccanismo adittivo per interpretare l'incremento del numero dei cromosomi.     

The effects of halothane on ovulation in the rat

Zusammenfassung Halothan-Anaesthesie während der sogenannten «kritischen Periode» der Proöstrusphase bewirkt eine zentrale Hemmung der Spontanovulation bei der Ratte. Wie Barbiturate und Urethan ist deshalb Halothan als Anaesthetikum zur Erforschung neuroendokriner Mechanismen nur in beschränktem Masse geeignet.

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Supported by a group grant in Developmental Neurobiology from the Canadian Medical Research Council.