Accession Number:

AD0671943

Title:

DIFFERENTIAL LETHAL EFFECTS OF MIXED REACTOR RADIATIONS ON LOGARITHMIC-PHASE AND SYNCHRONIZED TETRAHYMENA PYRIFORMIS,

Descriptive Note:

Corporate Author:

NAVAL RADIOLOGICAL DEFENSE LAB SAN FRANCISCO CALIF

Personal Author(s):

Report Date:

1968-04-29

Pagination or Media Count:

18.0

Abstract:

Logarithmic-phase and heat-shock synchronized Tetrahymena pyriformis cells were subjected to mixed neutron-gamma radiations 2.71 from a Mark F Triga reactor. A median lethal dose LD5048 hours for logarithmic-phase cells was 70 krads 95 confidence interval 68 to 73. The LD5048 hours for heat-treated cells irradiated at 6 minutes after the end of the synchronizing treatment was 174 krads 95 confidence interval 170 - 178. The approximately 2.5-fold resistance of heat-treated cells relative to logarithmic-phase cells might be related to the fact that heat-treated cells at the end of the synchronizing treatment contain 2 - 4 times the amounts of DNA found in logarithmic-phase cells. However, since heat-treated cells also are 2 - 4 times larger and contain 2 - 4 times the amount of RNA, other factors cannot be excluded. The possibility that the resistance of synchronized cells results from being irradiated at a particularly insensitive stage in the cell cycle is discussed it is concluded that this explanation is unlikely. Author

Subject Categories:

  • Radiobiology

Distribution Statement:

APPROVED FOR PUBLIC RELEASE