Preadult lethality in four populations ofDrosophila melanogaster treated with formaldehyde

Summary Samples from 4 populations ofD. melanogaster were treated with formaldehyde by the larval feeding method, and induced lethality was scored. The results showed relevant differences among the populations analyzed.     

Separation of specific fractions of synaptosomes by affinity chromatography

Summary The authors describe a new technique for isolation of specific fractions of synaptosomes, on the basis of their surface glycoproteins, by affinity chromatography using lectin-Sepharose columns.     

Interaction of cocaine and bunaphtide on the3H-norepinephrine uptake mechanism on isolated left atrium of guinea-pig

Summary Bunaphtide induces a blockade in the³H-norepinephrine uptake and retention in the isolated guinea-pig left atrium. However, this blockade does not seems to be related with the cardiodepressant effect of the drug.     

Alteration in the SAT-chromosome ofAllium cepa affecting the size of the nucleolus

Resumen Se describe el hallazgo de un bulbo deAllium cepa en el cual los dos nucleolos de cada nÚcleo muestran una clara diferencia de tamaño. El nucleolo menor posee aproximadamente la mitad del diámetro del nucleolo normal. Esta alteración de la morfología nucleolar se correlaciona con la ausencia de satélite en uno de los dos cromosomas normalmente satelizados.

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The work reported in this paper was undertaken during the tenure of a Research Training Fellowship awarded by the International Agency for Research on Cancer.     

Effect of copulation or vaginal stimulation on melanocyte-stimulating hormone content of the hypophysis

Résumé Dans le rat, 1 h après la copulation, la concentration de l'MSH de l'hypophyse présente une diminution statistiquement significative, autant chez le mâle que chez la femelle. La stimulation vaginale avec une baguette de verre provoqua 60 et 120 min plus tard une diminution de la concentration de plus de 50% de l'MSH de l'hypophyse. Au bout de 30 min, on n'a observé aucun changement. On en déduit que la copulation ou la stimulation vaginale libère l'MSH.

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This investigation was supported by grant No. NB 04732-03 from the NIH, US. Public health Service.     

Studies on the quaternary structure of the first enzyme for histidine biosynthesis

Resumen Se han realizado estudios de asociación-disociación por filtración en gel con el primer enzima de la biosíntesis de histidina enEscherichia coli, en presencia de sustratos y ligandos. Se observa una interconversión reversible entre las formas dímero, tetrámero y exámero, y una agregación irreversible de orden superior.