The citrate cleavage enzyme activity in chick embryo and chicken liver during development

Riassunto La relazione tra le misure sperimentali dei livelli di attività del «Citrate cleavage enzyme» (E.C. 4.1.3.6.) e lo andamento dei processi neoglicogenetico e lipogenetico nel fegato di embrione di pollo e di pollo a vari tempi di sviluppo esclude che la scissione enzimatica del citrato partecipi alla neoglicogenesi e conferma il ruolo di questa reazione nella lipogenesi.

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This work was supported by grants from the Impresa Enzimologia of the Italian C.N.R.

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Post-doctoral fellow of the Scuola Normale Superiore, Pisa.     

Sexual differences in the development of plasma thyroxine levels in the embryo and young chick]

Plasma thyroxine (T4) levels were separately ascertained in male and female embryo and young chicken from the 12th day of incubation till the 4th day after hatching by the thyroxine binding globulin technique. In both sexes, plasma T4 reach a peak the 20th day of incubation, but values are significantly higher in females. A sharp decrease occurred thereafter, plasma T4 tending toward adult values the 4th day after hatching.     

Acetylcholine receptors in the gastrulating chick embryo

Summary Muscarinic acetylcholine receptors are present in the gastrulating chick embryo.     

Extended survival of the chick embryo in vitro

Résumé On décrit une technique pour obtenir la survie prolongée des embryons du poulet in vitro, et son emploie pour cultiver des tissus isolés du système nerveux centrale.     

The localization of acetylcholinesterase in the optic lobe in the developing chick embryo

Summary The localization of acetylcholinesterase (AChE) in the optic lobe in the developing chick embryo was studied histochemically and biochemically. The histochemical reaction of AChE increased remarkably between stage 42 and 44 especially in the neuropile. The increase of the biochemical activity of the AChE in the synaptic membrane fraction occurred at a later stage than that in the microsomal fraction. These findings can be interpreted as the result of axonal transport of the enzyme from the synthetic to the synaptic site.Acknowledgments. The authors wish to thank Prof. Yasuharu Kuwahara, Cataract Research Institute, for the use of his cryostat and other laboratory facilities, Dr. Koji Kami, Department of Anatomy, Keio University School of Medicine, for his valuable advice regarding histochemistry.