Establishment of three cell lines derived from frog melanophores

Three cell lines have been established from melanotic and amelanotic melano phores of wild and albino Rana nigromaculata and albino Rana porosa brevipo da after experiencing three culture crises. The population doubling rate in creased with culture time. Cells from both wild and albino R. nigromaculata changed shape twice in ten years. They began as large pigmented or non-pig mented epithelial-like cells at the beginning of the cultures. The melanoph ores of albino R. nigromaculata unexpectedly became pigmented shortly after the beginning of the culture. Over time, they transiently aquired a small, non-pigmented, bipolar morphology and finally became large non-pigmented e pithelial-like cells after about 8 to 10 years. On the contrary, cells from albino R. porosa brevipoda remained large, non-pigmented, epithelial-like cells over the entire course of the culture. Pigmented cells contained many mature melanosomes, while non-pigmented epithelial like cells contained pr emelanosomes with characteristic internal structures. Non-pigmented, fibrob last-like cells contained numerous small vesicles in place of typical preme lanosomes. The cells of established cell lines, including those from wild R . nigromaculata, were unpigmented and showed no tyrosinase activity in hist ochemical dopa reactions. The number of chromosomes deviated from the norma l pattern in the three cell lines. Each of the three cell lines had a diffe rent modal number than the other two, and the chromosomal compositions of t he cells within the same lines differed from one another. Even within the s ame cell lines, the mode changed as the culture progressed without any cons istent trends.