A collection of maize from Darien,Panama

A collection of maize obtained from the Chocó Indian tribe of Darien, Panama, differs from published accounts of maize reported as typical for the area in size and in methods of cultivation. The collection may represent a segregating population from crosses occurring between the racesChococeño andCoastal Tropical Flint. Implications of this hypothesis with regard to problems of introduction, present geographical occurrence, and transportation of these races by nomadic human vectors are briefly discussed.     

L'ültrastructure du Foie Humain Lors D'ictères Idiopathiques Chroniques

Summary 15 liver biopsies from 13 patients suffering from non-hemolytic constitutional jaundice (6 cases of Gilbert's, 2 cases of Rotor's and 5 cases of Dubin-Johnson's disease) provided the basis of an ultrastructural study of pigment inclusions in liver cells following various techniques of preparation.The lipofuscin in Gilbert's syndrom and the pigment characteristic of Dubin-Johnson's syndrom contain two distinct components which are present in both types of inclusions but their proportions are different in these syndromes: a globular component, probably of lipidic nature, is the main constituent of the lipofuscin, a granulo-filamentous component the main constituent of the Dubin-Johnson's pigment. These two components react in both syndromes identically to various techniques of fixation, embedding and section-staining. In Rotor's syndrome other pigment inclusions are observed which are not detectable in ordinary histological preparations: they consist essentially of aggregates of dense, ferritin-like material. The presence, in the hepatocytes, of pigment inclusions which have some features in common in the 3 types of syndromes and other characteristics specific for each of them, confirms the close relation between these types of jaundice, but emphasizes also their differences; moreover, this ultrastructural study underlines the difficulty of an exact classification of these syndromes.

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Travail subventionné par la Fondation Fritz Hoffmann-La Roche pour l'expansion en Suisse du travail scientifique exécuté par équipe et par le Fonds National Suisse de la Recherche Scientifique.

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Avec la collaboration technique de Mlle M.-M. Bertholet.     

Rhodopseudomonas viridis,nov. spec., ein neu isoliertes,obligat phototrophes Bakterium

Zusammenfassung Nach Untersuchung von Morphologie, Feinstruktur und Ernährungsphysiologie wird ein neu isoliertes grünes Bakterium in die Gattung Rhodopseudomonas eingeordnet und der Artname Rhodopseudomonas viridis vorgeschlagen.

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Summary Rhodopseudomonas viridis was isolated from different waters near Freiburg im Breisgau. It is a gramnegative bacterium which is motile by means of polar flagella. Cells are usually distinctly rod-shaped, occasionally the rods are lightly curved. The size is variable, the dimensions 0.6 to 0.8 by 1.5–2.5 . Dense suspensions of this Rhodopseudomonas species are green coloured. The colour is changed in older cultures to a dirty brown-green. The absorption-maxima of the in-vivo spectrum at 400, 606 and 1020 nm are attributed to bacteriochlorophyll b, while the peaks at 451 and 483 nm reflect the presence of carotenoids. The bacteria grow only anaerobically in the light. They are strictly photo-organotroph. Heavy growth is observed in media which contain malate, succinate, pyruvate or acetate as carbon source and ammonia as nitrogen source. p-amino-benzoic acid, biotin and vitamin B are required. Yeast extract (0.05%) and casamino acids stimulate but fatty acids with the exception of acetate inhibit growth. No development is observed with carbon dioxide as sole carbon source. Gelatine is not liquefied. Nitrate is not reduced to nitrite.