Dimethyloxarsylethanol from anaerobic decomposition of brown kelp (Ecklonia radiata): A likely precursor of arsenobetaine in marine fauna

Summary The novel arsenic compound, dimethyloxarsylethanol, has been isolated from anaerobically incubatedEcklonia radiata. It is proposed that this compound has a key position in the biosynthesis of arsenobetaine.C, H microanalyses were performed by the Australian Microanalytical Service.     

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.     

Purification of a protein binding quinacrine and histrionicotoxin from membrane fragments rich in cholinergic receptors in Torpedo marmorata]

A protein is purified by differential centrifugation from membrane fragments rich in acetylcholine receptor prepared from Torpedo marmorata electric organ after dissolution by a mixture of non denaturing detergents. After polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate and Coomassie blue staining the purified protein yields a single band of apparent molecular weight 43,000. Spectroscopic experiments carried out in the absence of Ca++ and detergents reveal that the 43 K protein interacts with the fluorescent local anesthetic quinacrine and with the frog toxin histrionicotoxin (apparent KD : 7 X 10(-7) M) but not with carbamylcholine and the alpha toxin from N. nigricollis.