Lysosomes, intranuclear organelles endowed with several lytic enzymes (including acid phosphatase or acid protease, acid desoxyribonuclease, and acid ribonuclease), range in size from 0.25μ to 0.8μ. Ultraviolet light releases the proteases from lysosome by weakening its membrane. Allison and Malucci1 have suggested that lysosomes may be involved in the control of cell division. A rearrangement followed by disappearance of lysosomes precedes cell division. Nondividing cells have several lysosomes which tend to concentrate at one pole of the nucleus; in dividing cells, a small number of lysosomes are seen at the periphery of cells. A release of lysosomal substance into the cytoplasm may act on a trigger mechanism, initiating division in a cell that is prepared to divide.
There are two systems of cells in which division does not normally occur, unless induced by special manipulation: the liver cells and the human peripheral lymphocytes. Allison and Malucci showed that, following
THE LYSOSOME. JAMA. 1965;192(4):321–322. doi:10.1001/jama.1965.03080170049014