Sur l'histoire du théorème fondamental de l'algèbre: théorie des équations et calcul intégral

Sans résumé Mémoire présenté par U. Bottazzini     

High molecular transport proteins for JH-III in insect hemolymph

Summary Using two independent techniques, ultracentrifugation in a KBr-gradient, and native pore polyacrylamide gel electrophoresis in combination with [³H]-epoxyfarnesyldiazoacetate photoaffinity labeling, we showed that in the hemolymph ofPeriplaneta americana, and probably also inLeptinotarsa decemlineata JH-III binds to the lipophorin, whereas inLocusta migratoria JH-III binds to a different protein.     

Phorbol ester and diacylglycerol mimic growth factors in raising cytoplasmic pH

There is now good evidence that cytoplasmic pH (pHi) may have an important role in the metabolic activation of quiescent cells. In particular, growth stimulation of mammalian fibroblasts leads to a rapid increase in pHi (refs 3-6), due to activation of a Na+/H+ exchanger in the plasma membrane, and this alkalinization is necessary for the initiation of DNA synthesis. However, the mechanism by which mitogens activate the Na+/H+ exchanger to raise pHi is not known, although an increase in cytoplasmic free Ca2+ ([Ca2+]i) has been postulated as the primary trigger. We now present data suggesting that the Na+/H+ exchanger is set in motion through protein kinase C, a phospholipid- and Ca2+-dependent enzyme normally activated by diacylglycerol produced from inositol phospholipids in response to external stimuli. Using newly developed pH microelectrodes and fluorimetric techniques, we show that a tumour promoting phorbol ester and synthetic diacylglycerol, both potent activators of kinase C (refs 12-15), mimic the action of mitogens in rapidly elevating pHi in different cell types. Furthermore, we demonstrate that, contrary to previous views, an early rise in [Ca2+]i is not essential for the activation of Na+/H+ exchange and the resultant increase in pHi. Finally, we suggest that an alkaline pHi shift, mediated by Na+/H+ exchange, may be a common signal in the action of those hormones which elicit the breakdown of inositol phospholipids.     

Influence of dormancy on the chemical composition ofStrophocheilus (Strophocheilidae,Pulmonata, Mollusca)

Résumé Pendant l'hibernation, leStrophocheilus (Pulmoné, Mollusque) perd de l'eau, du sodium, du calciun, du magnésium, du soufre, du cuivre, du fer et des carbohydrates totaux, mais son taux de potassium et d'iode augmente. En état d'estivation, il y en a perte d'eau, de sodium, de magnésium, de cuivre, de fer et de carbohydrates totaux, mais accumulation de calcium.     

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.     

On the question of American eels,Anguilla rostrata versus European eels,Anguilla anguilla

Zusammenfassung Der amerikanische AalAnguilla rostrata (2n=38; 20M+18A) gehört einer anderen Spezies an als der europäischeAnguilla anguilla (2n=38; 32M+6A).

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This work was supported in part by a grant No. CA 05138 from the National Cancer Institute, U.S. Public Health Service.