The isolation of mossy fibre endings from the granular layer of the cerebellar cortex

Résumé Les boutons terminaux des fibres moussues du cervelet ont été separés des petits boutons de la couche moléculaire après homogénéisation et fractionnement. La fusion intracytoplasmique des vésicules synaptiques se produisant sous l'effet de la chaleur indiquerait un mécanisme de libération du médiateur.

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The work was supported by USPHS grant No. NB 03928-03 from the National Institute of Neurological Diseases and Blindness. The electron microscope was provided by the Wellcome Trust. The participation of Dr.M. N. Sheridan in the early stages of this work and the technical assistance of MissL. Swales are gratefully acknowledged.     

The metabolism of biphenyl byPseudomonas putida

Riassunto La degradazione del bifenile da parte diPs. putida inizia con la formazione di un diolo cui si attribuisce la struttura di 2,3-diidro-2,3-diossibifenile, in quanto, per disidratazione a caldo con acido cloridrico, si trasforma in 2-ossibifenile e tracce di 3-ossibifenile. Il diolo viene ulteriormente degradato ad acido benzoico. Le cellule diPs. putida cresciute su bifenile sono simultaneamente indotte ad ossidare al Warburg il bifenile e l'acido benzoico, non il 3,4-diossibifenile e l'acido fenilpiruvico. Le stesse cellule contengono una metapirocatecasi costitutiva.

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This work was supported by a grant of C.N.R. (Consiglio Nazionale delle Ricerche), for the International Biological Program.     

Localization of the X inactivation centre on the human X chromosome in Xq13

X-chromosome inactivation results in the strictly cis-limited inactivation of many but not all genes on one of the two X chromosomes during early development in somatic cells of mammalian females. One feature of virtually all models of X inactivation is the existence of an X-inactivation centre (XIC) required in cis for inactivation to occur. This concept predicts that all structurally abnormal X chromosomes capable of being inactivated have in common a defineable region of the X chromosome. Here we report an analysis of several such rearranged human X chromosomes and define a minimal region of overlap. The results are consistent with models invoking a single XIC and provide a molecular foothold for cloning and analysing the XIC region. One of the markers that defines this region is the XIST gene, which is expressed specifically from inactive, but not active, X chromosomes. The localization of the XIST gene to the XIC region on the human X chromosome implicates XIST in some aspect of X inactivation.     

Immunological selection of tumour cells which have lost SV40 antigen expression.

In an already tumorigenic spontaneously transformed mouse cell, after further transformation by SV40, the virus-specific antigenic function becomes dominant. By transplantation into syngeneic mice SV40 antigen negative revertant tumour cells can be selected out.