Normal larvae obtained from dark fragments of centrifugedCiona eggs

Riassunto Dei due frammenti, jalino e pigmentato, ottenuti per centrifugazione dall'uovo vergine diCiona intestinalis, solo il frammento scuro è capace di svilupparsi. Da esso può aversi una larva completamente normale. Questo risultato è spiegato attribuendo un valore morfogenetico ai mitocondri che sono presenti esclusivamente nel frammento scuro.     

Slow periodicity in the dark discharge of retinal units

Riassunto La registrazione microelettrodica della retina del gatto « cerveau isolé » adattato completamente all'oscurità ha messo in evidenza talvolta una attività ritmica a lungo periodo, nella scarica delle cellule ganglionari.     

Changes in photoelectron transport of chloroplasts isolated from dark stressed leaves of maize seedlings

Summary Transfer of light-grown maize seedlings to dark causes a loss in the contents of chlorophyll, protein and RNA of leaves, and a decline in DCPIP photoreduction by isolated chloroplasts. The loss in DCPIP-Hill reaction is attributed to the dark stress-induced damage of O₂ evolving system of thylakoid membranes.Acknowledgment. We thank Prof. M.C. Dash, School of Life Sciences, for encouragement and providing the facilities.     

Vitamin requirements of decotylised pea seedlings cultivated in the dark

Zusammenfassung Abgeschnittene Erbsenwurzeln wachsen, wie schon frühere Untersuchungen gezeigt haben, unbegrenzt in einer Nährlösung mit Thiamin (Vitamin B₁) und Niacin als die einzigen zugesetzten Vitamine. Das konnte auch mit der in dieser Arbeit verwendeten Erbsenrasse bestätigt werden. Dekotylisierte Erbsenkeimlinge, die unter denselben Bedingungen in Dunkelheit kultiviert wurden, brauchten aber Thiamin undPyridoxin (Vitamin B₆). Ein Bedürfnis von Niacin zeigte sich dagegen während der angewandten Versuchszeit bei diesen Keimlingen nicht.     

Absence of recovery in the dark of chloroplast formation in UV-irradiatedEuglena

Summary UV-irradiatedEuglena showed recovery of liquid holding, as indicated by cell survival, but not of chloroplast formation. The addition of caffeine after UV-irradiation decreased the fraction of cells surviving, but had no effect on the chloroplast formation.     

Changes in photoelectron transport of chloroplasts isolated from dark stressed leaves of maize seedlings.

Transfer of light-grown maize seedlings to dark causes a loss in the the contents of chlorophyll, protein and RNA of leaves, and a decline in DCPIP photoreduction by isolated chloroplasts. The loss in DCPIP-Hill reaction is attributed to the dark stress-induced damage of O2 evolving system of thylakoid membranes.     

Antifungal substances found in leaves of Eucalyptus species

Summary Antifungal substances were detected in leaves of 11 out of 27 Eucalyptus species examined. It was shown that antifungal substances found in the Eucalyptus species examined consist of from 1 to 4 different components.Acknowledgment. Gratitude is extended to Dr D. Mossop, Department of Plant Pathology, Waite Agricultural Research Institute, South Australia, Australia, for reading the draft.     

Triple cones found in retinas of 3 fish species

Summary Triple cones were found in the retinas of 3 species of fishes indigenous to the Woods Hole area. The function of these triple cones can not be deduced from the behavior patterns of these fishes.We wish to thank Kathleen French for her advice and criticism in the preparation of this paper.     

Electrophysiological evidence for a neural stage in dark adaptation

Riassunto Risposte elettroretinografiche sono state registrate dall'occhio di gatto. Sono state studiate le variazioni di ampiezza dell'ondab e del potenziale del ricettore (isolato tramite fotocoagulazione dell'arteria retinica) durante l'adattamento all'oscuro. L'analisi dei risultati ha dimostrato l'esistenza di uno stadio nervoso nell'adattamento all'oscuro con sede anatomica fra il ricettore e lo strato dei granuli interni.

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This research has been sponsored jointly by the Office of Scientific Research, EOAR, through the European Office, Aerospace Research, United States Air Force, under Contract No. AF 61 (052)-830.     

Ultrastructure of a mucous gland cell found in the tube feet of the starfishAsterina stellifera

Resumen Es describida la ultraestrutura de un segundo tipo de célula glandular mucosa que es encontrada en el pié ambulacrario de la estrella del marAsterina stellifera. Los gránulos secretores de esta célula tienen en su interior una ultraestrutura en forma de pequeños puntos densos y delicadas fibrillas, mas faltando una organizatión, principalmente comparada con la organizatión del otro tipo de granulo mucoso, también encontrado en el mismo pié ambulacrario.     

Triple cones found in retinas of 3 fish species.

Triple cones were found in the retinas of 3 species of fishes indigenous to the Woods Hole area. The function of these triple cones can not be deduced from the behavior patterns of these fishes.     

Sex attractant of the larch bud moth found by electroantennogram method

Zusammenfassung Mit Hilfe der Antennogramm-Methode wurdetrans-11-Tetracedenylacetat als spezifisches Attraktans für Männchen des LärchenwicklersZeiraphera diniana bestimmt. In geeigneter Konzentration ist die Attraktivität der synthetischen Substanz derjenigen virginer Weibchen ebenbürtig.

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This research was supported in part by Environmental Protection Agency Grant No. EP-00802 and by the Rockefeller Foundation.

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Contribution No. 46 of the research team for the investigation of the population dynamics of the larch bud moth, directed by Professor Dr.P. Bovey. The research was aided by the Swiss National Funds for Scientific Research.     

Hemisphaericin-D,a dialysable and polymerizable protease found in Bromelia hemisphaerica

Summary Proteolytic activity was detected outside dialysis bag filled with Bromelia hemisphaerica fruit juice. The dialysable protease was concentrated and purified from small molecular weight contaminants on Sephadex G-10 columns. Acrylamide gel electrophoresis of the dialysable protease, in the presence of SDS and 2-mercaptoethanol. demonstrated a single protein band of about 8000 daltons mol. wt. The same single band with identical mobility was shown with hemisphaericin, the enzyme retained inside the dialysis bag. The small protease, named Hemisphaericin-D was antigenic in rabbits and the antibodies cross-reacted fully with Hemisphaericin. Hemisphaericin-D appears not to be a degradation product of Hemisphaericin.This is contribution No. 22 from Departamento de Biología Experimental, Facultad de Medicina, UNAM, Mexico.Acknowledgments. We thank Irma Coria and Silvia Vizconde for skillful assistance. Interchange of information with Dr E. Toro-Goyco, University of Puerto Rico, School of Medicin, was most helpful.     

Effect of light and dark pulses on the emergence rhythm ofDrosophila pseudoobscura

Zusammenfassung BeiDrosophila pseudoobscura synchronisiert ein einmaliger Übergang von Dauerdunkel zu Dauerlicht und von Dauerlicht zu Dauerdunkel das Schlüpfen der Fliegen aus dem Puparium (Figur 2). Die Ergebnisse von Licht-Puls- und Dunkel-Puls-Experimenten lassen sich als Überlagerung solcher einfachen Stufeneffekte erklären.