Benzpyrene-induced tumours in the clawed toad,Xenopus laevis

Résumé Quelques cristaux de benzopyrène furent implantés dans trente-trois amphibiens anoures (Xenopus laevis laevis), vingt d'entre eux montrèrent des lymphosarcomes à différents endroits, le plus souvent localisés dans le foie et les reins. Ces tumeurs induites furent transplantées à nouveau avec succès.     

A new cell line (XTY) from a tumor of Xenopus laevis.

A new cell line (XTY) was derived from a tumor of a female Xenopus laevis. This cell line has been proliferating in standard amphibian culture medium for more than 4 years (470 generations) and has a doubling time of 75.5 h at 25 degrees C. The cells aggregate into large groups, and their stellate morphology and the expression of desmin demonstrated by immunocytochemistry suggest that their origin is not epithelial.     

A new cell line (XTY) from a tumor ofXenopus laevis

A new cell line (XTY) was derived from a tumor of a femaleXenopus laevis. This cell line has been proliferating in standard amphibian culture medium for more than 4 years (470 generations) and has a doubling time of 75.5 h at 25°C. The cells aggregate into large groups, and their stellate morphology and the expression of desmin demonstrated by immunocytochemistry suggest that their origin is not epithelial.     

The importance of the lateral line system for the perception of surface waves in the claw toad,Xenopus laevis daudin

Zusammenfassung Blinde Krallenfrösche reagieren auch dann auf konzentrische Oberflächenwellen, wenn das gesamte Seitenliniensystem zerstört wird. Weitere Ausschaltversuche zeigen, dass der Reiz (Eintauchen eines Stabes) sehr wahrscheinlich über das Labyrinth perzipiert wird. Ob die Oberflächenwelle selbst oder (und) das Geräusch beim Eintauchen des Stabes wahrgenommen wird, ist noch nicht sicher entschieden.

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My thanks are due to Dr.M. L. Mittelstaedt for critical help and to MissA. Middelmann for valuable technical assistance. This work was partly supported by a grant from the DFG.     

Identification of a catecholamine in the skin of the toad,Xenopus laevis,and the relation to the physiological melanophore reaction

Zusammenfassung Mit Hilfe chemischer und histochemischer Technik gelingt in der Haut vonXenopus laevis der Nachweis eines dopamingefüllten Reservoirs. Das Catecholamin ist mit der physiologischen Melanophorenreaktion verbunden.

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The authors are indebted to Prof. J. C. van deKamer for his encouragement and interest in these studies.     

Regeneration of the testes in the clawed toad (Discoglossus pictus Otth.) after complete surgical removal

Riassunto Dopo ablazione totale dei testicoli inDiscoglossus pictus si ha rigenerazione. Nei testicoli rigenerati si riscontrano spermatociti in tutti gli stadi di sviluppo e talvolta anche spermi. È avanzata l'ipotesi che la rigenerazione avvenga a partire da cellule somatiche degli spermidutti.

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With a contribution from the C.N.R.     

Elimination and metabolism of dimethylnitrosamine (DMN) by Xenopus laevis and other amphibians

The elimination of (14C)-DMN after i.p. injection into Xenopus was measured, as was the metabolism in vitro of (14C)-DMN by liver from Xenopus and 9 other amphibian species. In view of its rapid elimination from the body and low rate of metabolism by Xenopus liver in vitro, DMN is unlikely to be toxic or carcinogenic in Xenopus.     

The effect of concanavalin-A on the reaggregation of cells dissociated from Xenopus laevis early embryos

Summary The effects of concanavalin-A on the reaggregation and sorting of cells from Xenopus laevis early embroys have been studied. The results suggest that at high concentrations, concanavalin-A can prevent reaggregation.     

Particle aggregates in plasma and intracellular membranes of toad bladder (granular cell)

Summary Freeze-fracture of granular cells of toad urinary bladder (Bufo marinus) reveals the presence, hitherto undescribed, of intramembranous particle aggregates in intracytoplasmic structures (tubules, vacuoles and vesicles) both in resting and vasopressin-stimulated epithelia.This work was supported by grants No. 3.553.75, 3.120.77 and 3.1300.73 from the Swiss National Science Foundation.The authors are indebted to Mrs Marthe Sidler-Ansermet, Miss Jacqueline Rial and Mr Michel Bernard for valuable technical assistance.     

Establishment of normal diploid and malignant heteroploid cell lines from non-treated and benzo(a)pyrene treated hamster embryo cell cultures

Summary Two normal diploid control cell lines and a heteroploid malignant transformed cell line from B(a) P treated hamster embryo cell cultures were established. The 14-month-old B(a)P transformed cell line grew 8-times faster than the 20-month-old control cell line. The control cell line showed normal diploid chromosome complement in 93% cells and heteroploidy in 7% cells while B(a)P treated line showed 83% heteroploid cells and only 17% diploid cells. This is the first report on the establishment of diploid hamster cell cultures grown for extended period. Acknowledgments. This work was supported by the French Ministry of Quality of Life, by the Institut National de la Santé et Recherche Médicale, by the S.E.I.T.A. and by Contract No. 12-14-7001-297 of the Agricultural Research Service, U.S. Dept. of Agriculture, Administered by the Athens, Georgia Area, Richard B. Russell Agricultural Research Center, Athens, Georgia 30604, USA. We thank Mr.B. R. Sharma, Mr.E. J. Radin, Dr.R. Hakim and Dr.Ved Brat for their help during this work.