Length measurement of gut segments for mucosal transport studies

Résumé La longueur des segments d'intestin de rat, mesurée in vivo sous une anesthésie profonde à l'ether et in vitro, dans une solution tampon à 25 °C, atteint environ le 94% et le 80% de la longueur des segments totalement relâchés. L'une ou l'autre de ces mesures semble assez constante pour être employée dans la standardisation des méthodes en usage dans la plupart des études sur le transport mucosal.

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This work was supported by the Medical Research Council of Canada.     

The antennae and mating behaviour ofDrosophila females

Summary The females ofDrosophila bipectinata andD. malerkotliana are able to discriminate between their own and alien males in the absence of antennae. Thus mate recognition seems to depend on contact chemoreceptors in these 2 species.We are grateful to the Head of the Department of Zoology, B.H.U. for providing the necessary facilities. Thanks are due to the U.G.C., New Delhi, India for awarding a junior research fellowship to O.P.S.     

Ethylene production and cell wall formation in mesophyll protoplasts

Summary The regulation of ethylene synthesis, in relation to the presence of a new cell wall, has been investigated forNicotiana sylvestris leaf protoplasts. It is clear that the production of ethylene is not controlled by the new wall, which has no action on the ethylene formation. The addition of dichlorobenzonitrile to cultivated protoplasts causes the inhibition of wall formation, without any other apparent deleterious effects.     

Development of an enzyme linked immunosorbent assay (ELISA) for measurement of vitellogenin concentrations in cockroaches

Summary A competitive enzyme linked immunosorbent assay was developed for the quantification of a large lipoprotein, namely the yolk protein vitellogenin, in the haemolymph of cockroaches (Nauphoeta cinerea). This assay was found to be specific, reproducible and it has a high sensitivity (approximately 10 ng).Acknowledgments. We would like to express our thanks to Prof. H. Fey and Ms H. Pfister, Veterinary Bacteriological Institute, University of Berne, for introducing us into the ELISA methodology, to P. Beyeler for technical assistance and to M. Kaltenrieder for drawing the graphs. We also thank the Sandoz Foundation for a fellowship to M. Dumas and the Swiss National Science Foundation (grant No. 3. 188-0.77) for financial support.     

Receptors for thymosin fraction V on rat thymic lymphocytes

Summary Binding by rat thymus lymphocytes of thymosin V, labeled with colloidal gold, was studied. Under the experimental conditions employed at least 2.8% cells exhibited thymosin binding sites.This article originally appeared in Experientia 38 (5) 1982, p. 618 but was accompanied by imporperfigures. Supported by Polish Academy of SciencesThe authors thank Dr A.L. Goldstein for the gift of thymosin. Also are grateful to Dr J. Jaroszewski for helpful discussion.