Behavioural endocrinology: no hormonal response in tied fights

Androgens are the principal sex steroids controlling reproduction and aggression in male fish, but their production can also be affected by social interactions. Here we show that androgen concentrations are not significantly increased in cichlid fish (Oreochromis mossambicus) that are fighting their own image in a mirror, despite their aggressive behaviour towards the virtual intruder. Our results indicate that the hormonal response normally triggered in male contests is not induced under these circumstances by the act of fighting itself, and that it may therefore depend on some indicator of relative fighting ability that cannot be delivered by a mirror-image challenger.     

Circles in spermatocyte chromatin loops. Electron microscopy and AgAs-NORs studies

Summary We describe the production of circles in chromomeric loops during the pachytene stage of the spermatocytes. These circles are found attached to chromatin or already free in the nucleoplasm. Each circle measures an average of 3700 Å in circunference. We suggest that such circles might indicate the presence of tandem repetitions.This work was supported by grants from Brazilian National Research Council-CNPq, Fundaçaó de Amparo à Pesquisa do Estado de S. Paulo-FAPESP and Instituto Butantan Research Found-FEDIB.We are grateful to Dr A. Brunner, Jr, for the permission to use the electron microscope.     

Influence of chlorpromazine on nuclear and cytoplasmic uptake of35S-methionine

Résumé Des rats ont été traités avec de la chlorpromazine et ont reçu en suite une seule injection de³⁵S-méthionine. Des radioautographies des coupes histologiques ont montré que la chlorpromazine a un effect inhibitoire dans la synthèse de la protéine nucléaire et cytoplasmatique. Les cellules qui ont une grande vitesse de synthèse protéique sont les plus affectées.

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This investigation was supported by grants from the Rockefeller Foundation and Conselho Nacional de Pesquisas.

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The authors wish to acknowledge the help of Prof. L. C. U.Junqueira for criticism and encouragement, and MissEdna Freymüller for her skilled technical assistance.     

Alsatian chemists in Paris in the 19th century: a network, a school?

During the nineteenth century French chemistry was marked by an outstanding number of Alsatian chemists whose scientific contributions cannot be ignored. Especially following the Franco-Prussian War, their regional origin was given a particular importance as a means of affirming their singularity on the French scientific scene. However, some questions may be raised: can we distinguish the Alsatians from other French chemists before 1870? Were they a homogeneous group sharing a common origin? The aim of this article therefore, is, to show that by their theoretical options within chemistry, their personal and professional relationships, as well as by their participation in various common initiatives, they organized themselves both formally and informally within the Parisian scientific community. Amongst these forms of organization the research school of Charles Adolphe Wurtz (1817-84) emerges as the nucleus of what we may envisage as a network of Alsatian chemists working in Paris, in the second half of the nineteenth century.     

Chimistes alsaciens à Paris au 19ème siècle: un réseau,une école?

Au 19ème siècle, on remarque la présence, dans la chimie française, d'un nombre considérable d'Alsaciens dont les contributions scientifiques ne peuvent être ignorées. Essentiellement à la suite de la guerre franco-prussienne, leur origine régionale est souvent mise en avant afin de leur attribuer une certaine singularité: mais peut-on distinguer les Alsaciens des autres chimistes français avant 1870? Forment-ils un groupe homogène de par la spécificité de leur lieu d'origine? Cet article a pour but de démontrer que, par leurs options théoriques, leurs relations personnelles et professionnelles et aussi par leur participation à bien d'initiatives communes, ils se sont organisés au sein de la communauté scientifique parisienne. Parmi ces formes d'organisation, on dégage le rôle fondamentale de l'école de recherche du chimiste Adolphe Wurtz (1817–84) qui apu fonctionner comme noyau de ce qu'on peut considérer comme un vrai réseau de chimistes alsaciens à Paris, pendant la seconde moitié du 19ème siècle.