Adipose tissue ofDrosophila melanogaster : VI. Nonsusceptibility of the immature larval fat body to the lytic environment of the young adult.

Using transplantation techniques it was shown that immature and supposedly mature stages of fat body from the larvae ofDrosophila melanogaster do not lyse rapidly in the lytic, internal environment of the young adult. In the younger tissue the protein granules (probably lysosomes) were just beginning to form, whereas in the older tissue the protein granules were at a maximum level. In both cases the implanted tissues became steadily smaller independently of the environment. The decrease in implant size was interreted to mean that the cells were lysing, since the average cell size did not change, and since many cells appear cytologically degenerate. However, the estimated rate of cell loss was much slower than in the case where the cells pass through metamorphosis. Some of the immature cells produced relatively high amounts of protein granules independently of the environment. Although the protein granules are at a maximum amount in both stages, it would appear that additional development must be required for the cells to become susceptible to the lytic environment of the young adult.