Effect of ions on the light-sensitive current in retinal rods

The effect of ions on the light-sensitive current of retinal rods was studied by sucking the inner segment into a tightly fitting capillary with the outer segment projecting into a flowing solution. This new method showed that the light-sensitive pathway, in which Na+ is the normal carrier of current, has an ionic selectivity different from that of other known sodium channels. Externàl calcium has a striking effect on the current, which increased about 20-fold when all calcium was removed. Reducing the sodium concentration gradient greatly prolonged the response to a flash of light, as would be expected if internal calcium blocks sodium channels and if light releases calcium which is subsequently extruded by a sodium-calcium exchange mechanism.     

Kompensation der teratogenen Wirkung eines Thalidomid-Metaboliten durchl-Glutaminsäure

Summary Skeletal defects were observed in the off-spring of SWS-mice following i.p. administration of phthaloyl-l-glutamic acid, a metabolite of thalidomide. The fetuses of animals which receivedl-glutamic acid in addition to the teratogenic drug, did not show any malformations, whereas concurrent i.p. administration of thed-isomer of glutamic acid failed to reverse teratogenicity induced by phthaloyl-l-glutamic acid.     

Interaction of inhibitory and excitatory junctional potentials in the control of a myogenic myocardium: the ventricle ofBusycon canaliculatum

Résumé Les auteurs ont étudié, par microélectrode interne, l'interaction entre les potentiels postsynaptique inhibitoire et excitatif dans un myocarde myogénique. Ils ont observé la sommation de ces potentiels et leur action facilitant l'inhibition par hyperpolarization et l'excitation par depolarisation.

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Supported by a grant from the National Institutes of Health, USA (P.H.S. Grant No. 5-R01-NS-08352-03 PHY, from the National Institute of Neurological Diseases and Stroke.)     

Feeding activity ofMylabris pustulata Thunb. (Coleoptera: Meloidae)

Résumé L'activité nutritive deM. pustulata Thunb. est en général plus intense sur les plantes d'Hibiscus rosasciensis et sur ses fleurs particulier, à la lumière aussi bien que dans l'obscurité. La lumière ne joue donc pas de rôle important dans l'alimentation de cet insecte.

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The authors are indepted to Prof.H. S. Chaudhry for providing necessary facilities during the work.     

Metabolic status of temperature induced swollen conidia ofAspergillus nidulans

Summary There is an active synthesis of DNA, RNA, protein, and carbohydrate in conidia incubated at 48°C. DNA increases more or less 3 times; while RNA, protein and carbohydrate are synthesized at a much faster rate. Conidia do not germinate at this temperature.Acknowledgments. Grateful thanks are due to Professor B. M. Johri for valuable suggestions. R. K. S. acknowledges with thanks a Senior Research Fellowship of the Council of Scientific and Industrial Research, New Delhi.     

Synthesis of rhodotorucine A,the inducing factor of mating tube formation ofRhodosporidium toruloides

Summary The inducing factor of mating tube formation ofRhodosporidium turuloides, named rhodotorucine A (H-Tyr-Pro-Glu-Ile-Ser-Trp-Thr-Arg-Asn-Gly-Cys(S-farnesyl)-OH), has been synthesized to confirm the structure proposed for the natural lipopeptide. The synthetic S-farnesyl undecapeptide has identical Rf values on TLC using several different solvents, and also the same biological activity as the natural hormone.Acknowledgments. We wish to express our thanks to Drs E. Ohmura, M. Nishikawa and M. Yoneda of Takeda Chemical Industries and Dr I. Banno of Institute for Fermentation, Osaka, for their encouragement throughout this work.