A relation between G-, C-, and N-band patterns as revealed by progressive oxidation of chromosomes and a note on the nature of N-bands

Heterochromatic differentiation in barley chromosomes revealed by C- and N-banding techniques

Heterochromatin distribution in barley chromosomes was investigated by analyzing the C- and N-banding patterns of four cultivars. Enzymatic maceration and air drying were employed for the preparation of the chromosome slides. Although the two banding patterns were generally similar to each other, a clear difference was observed between them at the centromeric sites on all chromosomes. Every centromeric site consisted of N-banding positive and C-banding negative (N(+) C(-)) heterochromatin in every cultivar examined. An intervarietal polymorphism of heterochromatin distribution was confirmed in each of the banding techniques. The appearance frequencies of some bands were different between the two banding techniques and among the cultivars. The heterochromatic differentiation observed is discussed with respect to cause.

A rapid, simple and reliable combined method for G-banding mammalian and human chromosomes

A simple and reliable method for G-banding chromosomes from human and mammalian cells is described. This rapid method combines hot saline and trypsin treatments and yields high quality G-bands in both bone marrow and cultured cells.

Localisation of NORs and counterstain-enhanced fluorescence studies in Salmo gairdneri and Salmo trutta (Pisces, Salmonidae)

The karyotypes of the rainbow trout (Salmo gairdneri R.) and the brown trout (Salmo trutta L.) were analyzed by means of silver staining and the chromomycin A3/distamycin A/DAPI fluorescence banding technique. The nucleolus organizer regions (NORs) were localized at the secondary constrictions of chromosome no. 14 in S. gairdneri and of chromosome no. 10 in S. trutta. Additional silver positive dots were observed at or close to several centromeres in S. gairdneri. Brilliant chromomycin A3 (CMA3) fluorescence heterochromatin blocks were localized on both sides of the nucleolar constrictions in S. gairdneri. A polymorphic CMA3 positive band was detected close to the NORs of S. trutta. No distamycin A/DAPI intense heterochromatin blocks were detected in the genomes of the two Salmo species investigated.

Selective staining of the same set of nucleolar phosphoproteins by silver and Giemsa. A combined biochemical and cytochemical study on staining of NORs

Gel electrophoresis of nucleolar isolates from Zajdela ascites hepatoma cells followed by various staining procedures revealed a common set of bands that stained selectively with silver and Giemsa. The gel bands, corresponding to molecular weights of 104, 78, 37, and 29 kilodaltons (kd), appeared to contain phosphoproteins that were at least partly associated with oligo-deoxyribonucleotides. Enzyme digestion studies showed that the Giemsastainability was due to the phosphorylated state of the proteins. The positive selective silver-staining reaction in gels could be most likely attributed to the high content of carboxyl groups present in these phosphoproteins. The significance of these findings in relation to cytological results produced by selective silver staining of nucleolus organizing regions (NORs) and by Giemsa N-banding is discussed.