染色体分染法によるバンドの再現性と染色体標本の保存条件

Temperature conditions for preserving the unstained slide preparations of animal chromosomes were considered to improve reproducibilities of the C- and G-bands on the chromosomes after the differential stainings. Both mammalian and amphibian somatic cells were used for making chromosome preparations in vivo and in vitro. Differential stainings were applied to the slide preparations which were preserved for up to 6 months at certain temperatures as 4, -20, -70 and 36℃, respectively. Reproducibilities of the bands on the chromosomes were compared after various preservation periods.
The effective storage to prevent slide aging was much concerned with lower temperature under -20℃ rather than low humidity or high temperature in dried condition. The chromosome specimens stored for 6 months at -20°and -70℃ could produce nearly normal band patterns by the C-stains. In general, C-staining gave better reproducibility than G-staining in the same age of slides. No significant difference in producing the C-bands was detected between human and amphibian chromosomes stored under the low temperature. Low humidity, under 25% of relative humidity, helped to prevent the slide aging when compared with the unconditioned storage, but it was not as effective as the low temperature of 4℃. From these results, we presume that ages of the slide proceed denaturation of chromatin substances, especially DNA and/or protein, and that the deep freezing of the slides effectively prevent such denaturation ; consequently, it makes good production of banding patterns.