MARQUAGE A L'ARGENT AMMONIACAL DESCHROMOSOMES MITOTIQUES ET DES NOYAUX QUIESCENTS DE L'URODELE PLEURODELES WALTLII

Abstract

Silver ammoniacal staining (Ag-As), specific for nuclear organizer regions (NORs) of mammals, has been applied to the interphase nuclei and to the mitotic chromosomes of the Triton Pleurodeles waltlii Michahelles. The banding on the chromosomes by the silver preferentially stains the pericentromeric zones where, after cold treatment, secondary constrictions appear. The metaphase karyotype (2n = 24) consists of two pairs of NORs which also stain with silver but to a lesser degree. It is also the same for the centromeres. This banding of zones other than those of the NORs is notable, not only in connection with the observations made in the case of the mammals, but also in connection with results obtained with other amphibians. An interpretation is given. The interphase nuclei also present sites of silver deposit. In the majority of cases, the sites correspond to the nucleoli. Nevertheless, supernumerary sites of deposit were apparent in a number of nuclei. This phenomenon cannot be explained clearly.[Translated by the journal]