The question of lens regeneration from parts of the optic vesicle in the chick embryo

Résumé Après excision du cristallin des yeux d'embryons de poulet de 48–72 h d'incubation les vésicules optiques étaient cultivées in vitro ou sur le chorio-allantoöide d'autres embryons. Elles étaient cultivées en quelques cas seules et en autres cas avec l'ectoderme céphalique. Nouveaux cristallins ne se formaient que si l'ectoderme céphalique était inclus avec la vésicule optique et si les vésicules étaient prélevées des jeunes embryons. On peut conclure que les nouveaux cristallins se forment dans l'ectoderme céphalique par induction. Nous n'avons trouvé aucune évidence de régénération du cristallin des tissus de l'oeil.

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This work was supported by a grant from the National Research Council of Canada to D. J. McCallion.     

Short-term effects of colcemid on the rapid axonal transport of proteins in the optic pathway of chick embryos

Riassunto La somministrazione endoculare di piccole dosi di Colcemid in embrioni di pollo al 13° e al 18° giorno di incubazione diminuisce la sintesi proteica nella retina. Pur in misura diversa, i due farmaci bloccano il trasporto assonico di proteine dalle cellule gangliari retiniche al tetto ottico. Anche nell'embrione quindi il trasporto assonico dipende dalla integrità dei microtubuli neuronali.

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This work was supported by Consiglio Nazionale delle Ricerche (C.N.R.), Rome, Italy.     

A contribution to the study of lens regeneration capacity in chick embryos

Zusammenfassung Die Linsenregeneration beim Hühnchen tritt nur auf, wenn die Embryonen am 3. oder 4. Bebrütungstage operiert worden sind. Wenn die Operation später stattfindet, tritt keine Regeneration auf.     

Synaptic junctions in the developing chick optic tectum

Riassunto Giunzioni sinaptiche compaiono in differenti strati plessiformi del tetto ottico dell'embrione di pollo, a partire dal 12⁰ giorno di incubazione: aumentano di numero fra il 12^o ed il 18^o giorno e, in maniera critica, fra questo e le prime ore dopo la schiusa.

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This work was supported by a grant from the Consiglio Nazionale delle Ricerche (C.N.R.) Rome, Italy.     

Isolation of filaments of the chick lens

Summary A preparation of intermediate filaments isolated from the chicken lens is enriched with a 50,000 dalton polypeptide.This study was supported by research grant EY 01417 of the National Institutes of Health, Bethesda, Maryland, USA.     

Isolation of filaments of the chick lens

A preparation of intermediate filaments isolated from the chicken lens is enriched with a 50,000 dalton polypeptide.     

Biosynthesis of ascorbic acid in chick embryos

Summary Biosynthesis of ascorbic acid was found in the kidneys (mesonephros and metanephros) of the chick embryo as well as in the yolk sac membrane. The activity of L-gulonolactone oxidase in the yolk sac membrane suggested that it was the major source of ascorbic acid in the chick embryo.I am grateful to Dr R. Jenness (Univ. of Minnesota) for the generous gift of L-gulonolactone and to Dr B. Sanders (Univ. of Texas) for the chick embryo samples     

Biosynthesis of ascorbic acid in chick embryos

Biosynthesis of ascorbic acid was found in the kidneys (mesonephros and metanephros) of the chick embryo as well as in the yolk sac membrane. The activity of L-gulonolactone oxidase in the yolk sac membrane suggested that it was the major source of ascorbic acid in the chick embryo.     

Spontaneous peristaltic activity of veins of chick embryos and newly hatched chickens explantedin vitro

Résumé Les veines du système porte et la veine ombilicale gauche d'embryons de poulet dans la dernière semaine d'incubation et de poussins à l'éclosion ont été cultivéesin vitro. Les auteurs y ont démontré la présence de contractions péristaltiques spontanées. Ils pensent que cette activité contractile rythmique favorisein vivo la circulation dans ces territories veineux.