EFFECT OF CULTIVATION TEMPERATURE ON SENSITIVITY OF INFUSORIA TO INJURIOUS ACTION OF X RAYS

Journal Article · Wed May 01 04:00:00 EDT 1963 · Federation Proc.

OSTI ID:4706189

Kovaleva, N K

The study of the sensitivity of the infusorian. Paramecium caudatum, to ionizing radiation at different cultivation temperatures revealed obvious differences between infusoria kept at a temperature of 19 to 22 deg (room temperature) and of those kept at low temperatures, +4 deg and +5 deg (cold). The changes in the division rate of infusoria exposed to high dose rates of radiation for 2-min periods were caused, both by the direct action of radlation and by its indirect action, through the ionization and excitation of the water molecules composing the cell body, and not by chemical poisoning by products present in the surrounding aqueous solution. In room temperature infusoria, irradiation by a dose of 75 kr causes a period of 24 hr without division in 70% of individuals. The rate of division varies considerably during the first 2 to 3 weeks after irradiation. Structural disturbances occur in the micronucleus. In some individuals, there is fragmentation of the macronucleus. The cytoplasm becomes vacuolated. Irradiation of room temperature infusoria causes a disturbance of carbohydrate and lipid metabolism, as shown by an increase in the lipid content and a decrease in the glycogen. A period of 6 to 7 days without division is observed in cold infusoria after irradiation. The decrease in the rate of division by comparison with the control infusoria is very small. No changes are apparent in the nuclear apparatus except for a decrease in the size of the nucleoli in the macronucleus. Vacuolation of the cytoplasm occurs. The changes in the glycogen and lipid content after irradiation are less marked in cold than in room temperature infusoria. Irradiated cold infusoria, when placed in irradiated medium, show greater resistance than unirradiated room temperature infusoria. Our results indicate that infusoria which have become adapted to low positive temperatures possess greater radioresistance than infusoria cultivated at room temperature, which confirms yet again the importance of the physiological state of the organism and of external environmental factors in determining the sensitivity to ionizing radiation. (auth)

• Research Organization: Inst. of Cytology, Leningrad
• NSA Number: NSA-17-030318
• OSTI ID: 4706189
• Journal Information: Federation Proc., Journal Name: Federation Proc. Vol. Vol: 22
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

BIOLOGY AND MEDICINE
CARBOHYDRATES
CYTOLOGY
ENVIRONMENT
GLYCOGEN
IONIZATION
LIPIDS
METABOLISM
MICROORGANISMS
MITOSIS
MOLECULES
PARAMECIA
QUANTITY RATIO
RADIATION DOSES
RADIATION EFFECTS
RADIOSENSITIVITY
SOLUTIONS
SUGARS
TEMPERATURE
TOXICITY
VARIATIONS
WATER
X RADIATION