Establishment of Three Cell Lines Derived from Frog Melanophores

Three cell lines have been established from melanotic and amelanotic melanophores of wild and albino Rana nigromaculata and albino Rana porosa brevipoda after experiencing three culture crises. The population doubling rate increased with culture time. Cells from both wild and albino R. nigromaculata changed shape twice in ten years. They began as large pigmented or non-pigmented epithelial-like cells at the beginning of the cultures. The melanophores 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 epithelial-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 premelanosomes with characteristic internal structures. Non-pigmented, fibro-blast-like cells contained numerous small vesicles in place of typical premelanosomes. The cells of established cell lines, including those from wild R. nigromaculata, were unpigmented and showed no tyrosinase activity in histochemical dopa reactions. The number of chromosomes deviated from the normal pattern in the three cell lines. Each of the three cell lines had a different modal number than the other two, and the chromosomal compositions of the cells within the same lines differed from one another. Even within the same cell lines, the mode changed as the culture progressed without any consistent trends.