Immuno-cyto-adherence tests inXenopus laevis daud

Riassunto Si è studiata la natura delle cellule immunologicamente competenti della milza diX. laevis Daud. Mediante la tecnica della immuno-cito-aderenza, si è potuto constatare che tali cellule estratte da milze di animali immunizzati con globuli rossi di pollo e coniglio, rispondono ad uno solo o ad ambedue gli antigeni, che la percentuale delle cellule che reagiscono sia contro le emazie di coniglio che di pollo è di molto superiore a quella dei mammiferi e che tale percentuale non varia al variare delle dosi di antigene somministrato.     

Studies on lens regeneration inXenopus laevis

Zusammenfassung Es wurde die Regeneration der Augenlinse erwachsenerXenopus laevis nachuntersucht. Eine vollständige Entfernung der Linse gelang in wenigen Fällen. Die Neuentwicklung der Linse wurde nur von Linsenepithelresten, die nach der Lentektomie in der Kapsel zurückgeblieben waren, induziert.     

Sex linkage of malic enzyme inXenopus laevis

Genetic analysis of mME variants (mitochondrial malic enzyme, E.C. 1.1.1.40) inXenopus laevis revealed sex linkage of the mMe locus and indicated a WZ/ZZ type of sex determination. Codominant mMe alleles occur on both W and Z chromosomes, with a recombination frequency of 6.1%±1.5% between mMe and the sex-determining locus (or region).     

Induction of antibodies against pure proteins inXenopus laevis daud

Riassunto TreXenopus laevis Daud., mantenuti a temperatura costante di 25 °C, sono stati immunizzati con una proteina pura ad alto peso molecolare, l'emocianina diViviparus ater Cristofori et Jan. Tutti gli animali hanno rispoto con produzione di anticorpi altamente specifici e mercaptoetanolo sensibili. Si è potuto inoltre confermare che l'anticorpopoiesi inXenopus dipende dalla temperatura alla quale l'animale è tenuto durante il trattamento e che è stimolata dall'azione del cortisone.     

Effect of interrupting retino-hypothalamic connections on the melanophore response inXenopus laevis

Résumé On a estimé possible que les axones rétinohypothalamiques décrits chez certains amphibiens jouent un rôle dans le contrôle neuro-endocrinien de la pars intermedia de l'hypophyse. Mais si on sectionne chez desXenopus cette voie supposée, ces animaux peuvent néanmoins modifier la couleur de leur peau lorsqu'on les place sur les terrains différents. Il n'est donc pas vraisemblable que ces connections fassent partie d'un arc réflexe contrôlant la sécrétion de l'hormone mélanotrophique.     

Oocyte maturation in vitro: Contribution of the oviduct to total maturation inXenopus laevis

Summary Contact of progesterone matured oocytes ofXenopus laevis with the oviduct reduces the time necessary to attain cleavage capacity from 24 h to 3 h. Full maturity has been demonstrated by normal development of the matured eggs after fertilization.     

Exogenous melatonin and melanophore development inXenopus

Summary Xenopus larvae raised from stage 21 in melatonin solution and upon a dark background had fewer head melanophores at stage 48 than control animals not exposed to melatonin. Rearing larvae in melatonin solution seems to mimic rearing larvae on a light background.     

The control of onset of melanoblast differentiation inXenopus larvae

Summary Studies on the time of first appearance of melanophores in uniformly-sized vesicles of hypomeric tissues containing different masses of neural crest tissues suggest that regional differences in the time of first appearance of trunk melanophores inXenopus are regulated by regional variation in the population density of melanoblasts.This work was supported by the Science Research Council and presented in a thesis, University of Glasgow.The author thanks Professor D. R. Newth for his interest and valuable criticisms.     

Immigration of lymphoid precursor cells into the thymic rudiment inXenopus

Summary The origin of thymic lymphocytes was investigated, using a new reliable method to mark cells inXenopus. It was easily observed that extraneous cells immigrated into the thymic rudiment 4 days after fertilization and differentiated into a cell population identified as thymic lymphocytes in a fully developed thymus. Clearly, lymphoid precursor cells are of extrinsic origin.This work was supported in part by a grant from the Ministry of Education, Science and culture of Japan (No. 59770026).     

A chromosome mutation affecting the number of nucleoli inXenopus borealis Parker

Résumé L'examen cytologique de la descendance de 2Xenopus borealis révéla 50% d'individus dotés de noyaux à 1 et 2 nucléoles (situation normale) et 50% à 1, 2 et 3 nucléoles. Le caryotype de ces derniers démontra la présence de 3 organisateurs nucléolaires, au lieu de 2, l'origine de l'élément supplémentaire relevant d'une translocation réciproque entre 4 et 7.

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Supported by a grant (No. 3.60.68) from the Fonds national suisse de la Recherche Scientifique and the George and Antoine Claraz donation.

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Unpublished research in this laboratory has shown thatXenopus laevis borealis (Parker) is a species on its own right and we propose to name itXenopus borealis (Parker).

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Material collected byFischberg andKobel, who express their gratitude to the Fisheries and Game Dept. of Kenya for permission to collect frogs of the genusXenopus.

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Acknowledgments. The authors wish to thank Mrs.J. Tymowska and MissE. Ackermann for their technical advice; they are grateful to Mr.J. Jackson, MissM. C. Payot, MissL. Ricard and Mr.P. Grutter for their assistance and useful help.     

Inhibitory effect of actinomycin D on tail atrophy inXenopus larvae at metamorphosis

Zusammenfassung Xenopuslarven, denen zu Beginn der «Metamorphoseklimax» 0,1 Actinomycin D intraperitoneal injiziert wurden, zeigten eine erhebliche Verzögerung der Metamorphose. Biochemisch ist die Hemmung der Schwanzresorption bei behandelten Larven durch die geringe Aktivität der Gewebekathepsine gekennzeichnet.

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This work was supported by a grant from the Schweiz. Nationalfonds zur Förderung der wissenschaftlichen Forschung (Project 2546).     

Anti-N fromMoluccella laevis

Zusammenfassung In Samen vonMoluccella laevis gelang der Nachweis von Anti-N-Agglutinin mit besonders starker Wirkung auf NN-Erythrozyten.     

High frequency of mast cells in spleens of A-strain mice

Zusammenfassung Es wurden in Milz und Thymus von Mäusen des Stammes A/Ph Mastzellenvermehrungen beobachtet und mit den Mastzellenzahlen bei andern Mäusestämmen verglichen.     

Effect of Ftorafur on acid phosphatase activity in the liver of mice with transplanted lymphatic leukaemia

Zusammenfassung Nachweis, dass Ftorafur, N₁-(2-Furanidyl)-5-Fluorouracil das Überleben leukämischer Mäuse deutlich steigert und ausserdem als Lysosomen-Stabilisator wirken könnte, wobei die in vivo Stabilisierung der Lysosomen den antileukämischen Effekt dieses Zytostatikums unterstützen könnte.