Comparison of the localization of several muscle proteins in relaxed and contracted myofibrils.

The localization of several muscle proteins in relaxed and contracted myofibrils is compared. The morphology of the myofibrils and the behavior of these proteins was also investigated under extraction conditions.     

Effect of alcohol ingestion on the epithelial cell population in rat small intestine

Summary Chronic administration of alcohol to well-nourished rats led to striking changes in the small intestinal cell population. The present experiments corroborate the view that alcohol is directly toxic to the small intestine.The authors wish to thank Mr.P. R. Gaspar for the technical assistance.     

Does nitrogen mustard mimic the X-ray effects in any case?

Résumé Les effets de l'ypérite nitrée sur le cerveau et yeux de l'embryon du rat blanc ont été analysés. Seulement les embryons présentant un aspect normal ont été coupés et colorés. De larges centres de nécrose ont été trouvés sur les coupes tandis que les «rosettes» n'ont pas pu être décelées.Bien que connue comme radiomimétique, l'yperite nitrée ne mime pas les rayons X en ce qui concerne la formation des «rosettes» dans le cerveau.     

Possible role of cell contact in the control of a differentiation program in Dictyostelium discoideum]

Synthesis of cAMP-phosphodiesterase falls at the end of the aggregation phase in Dictyostelium discoideum. Exogenous cAMP pulses, known to induce they synthesis of that enzyme during the course of the aggregation process, do not prevent the shut off of enzyme synthesis. Specific intercellular contacts which form at the end of aggregation seem to be required for the inhibition of enzyme synthesis.     

Effect of light adaptation on electrical responses of the retinas of four species of bats.

The levels of light adaptation at which the retinas of 4 species of microchiropteran bats became unable to generate electroretinograms were progressively ordered. The order correlated well with light preferences based on activity patterns of the 4 species. These results suggest that the ability of the retina to function in ambient light may govern some natural behaviors of these bats.