UPTAKE OF ISOLATED CHLOROPLASTS BY MAMMALIAN CELLS

Mouse fibroblasts (L cells) in suspension culture incorporated isolated chloroplasts of spinach and African violets and isolated mitochondria of chicken liver. The organelles resided in the cell cytoplasm and were not contained in vacuoles or digestion vesicles. Green cells divided like normal cells. Green chloroplasts were followed for five cell generations or 5 days, at which time hybrid cells were greatly outnumbered by nongreen progeny cells. The ingested chloroplasts retained their structural integrity as determined by electron microscopy of organelles and hybrid cells and by analysis of photochemical activity and DNA in chloroplasts reisolated from cells after 1 or 2 days in culture.