INFLUENCE OF X RAYS ON THE DEVELOPMENT OF MELANOTIC TUMORS IN DROSPPHILA (DROSOPHILA MELANOGASTER). QUANTITATIVE STUDY
Irradiation of the embryos or larvae considerably increases the incidence of melanotic tumors in these flies. Irradiation of germinal cells does not influence development of tumors in flies developing from the cells. The presence of the tumor gene in the genotype of the egg or larva is an essential condition for the tumorigenic action of irradiation. The statistical distribution of tumors in irradiated populations conforms to Poisson's law, and it is independent of the stage of ontogenesis at the time of irradiation. The effects of several irradiation treatments are additive, and the incidence of tumors increases with the dose to an upper limit of 600 to 800 r. Beyond 1200 to 1500 r the incidence of tumors decreases as mortality increases. Between doses of 0 and 600 r the incidence of tumors rises linearly from 10% to 95%, respectively. In contrast, the slope of the curve of induction of tumors depends neither on the incidence nor on the level of tumor gene; it seems to be influenced by cytoplasmic and maternal factors. When irradiation increases the number of tumors, it simultaneously increases their size and rapidity of their appearance. Irradiation does not modify the histologic appearance of the tumors. Occasionally tumors were observed in the leucopoietic tissue of the larva. The phagocytic activity of blood cells was not affected by irradiation. The increased incidence of tumors in irradiated Drosophila cannot be attributed to selective mortality or to inhibition of defense factors against tumor cells. The failure of irradiation to have a tumorigenic effect in older larvae indicates that it does not affect the development and growth of tumors once formed. It is suggested that irradiation increases the sensitivity of larval cells to a tumor- inducing agent controlled by the tumor gene. A single dose of ultraviolet radiation did not influence tumorigenesis in Drosophila. (H.H.D.)
- Research Organization:
- Institut Pasteur, Paris
- NSA Number:
- NSA-17-001273
- OSTI ID:
- 4773676
- Journal Information:
- Bull. Assoc. Franc. Etude Cancer, Vol. Vol: 48; Other Information: Orig. Receipt Date: 31-DEC-63
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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ACIDITY
AGE
ANIMAL CELLS
BLOOD CELLS
BLOOD FORMATION
CARBON DIOXIDE
CARCINOGENESIS
CHROMOSOMES
CYTOLOGY
DECOMPOSITION
DISTRIBUTION
DROSOPHILA
DROSOPHILA MELANOGASTER
EGGS
EMBRYOS
EQUATIONS
FORMIC ACID
FREE RADICALS
GAMMA RADIATION
HYDROGEN
IMMUNITY
INSECTS
IONS
IRON SULFATES
IRRADIATION
LETHAL DOSE
MOLECULES
QUANTITY RATIO
RADIATION CHEMISTRY
RADIATION DOSES
RADIATION EFFECTS
RADIATION INJURIES
RADIOSENSITIVITY
REACTION KINETICS
STATISTICS
TISSUES
TUMORS
ULTRAVIOLET RADIATION
VOLUME
WATER
X RADIATION