Effect of ascorbate on radiosensitization of bacterial cells
The effect of ascorbate on the radiosensitization of Escherichia coli by 10/sup -3/ M KI was investigated over a concentration range of 0 to 10/sup -2/ M. The sensitization effect was reduced in the presence of ascorbate with increasing dose, but no additional protection was observed against radiation lethality. Irradiation of cells in the presence of NaI/sup 131/ showed a decrease in cell radioactivity with increasing concentration of ascorbate present during irradiation over a concentration range of 0 to 10/sup -3/ M. It is argued that ascorbate reduced the sensitizing effect by scavenging the iodine atoms which would have otherwise reacted with the cells. The sensitization by 10/sup -3/ M 2,2,6,6-tetramethyl-4-piperidone-N-oxyl (TAN) decreased with increasing concentration of ascorbate, but no net protective effect was noticed. It is suggested that a reaction between the two molecules took place because the optical absorption of ascorbate (10/sup -4/ M) at265nm decreased to half its value in the presence of equimolecular TAN, and also because the esr signal from 1 mM TAN decreased to a fifth of its value in 15 min after mixing with equimolecular solution of ascorbate. The presence of ascorbate during irradiation at concentrations from 10/sup -6/ M to 10/sup -3/ M did not affect the radiosensitization of anoxic E. coli cells by 5 x 10/sup -5/ M of N- ethylmaleimide (NEM). (UK)
- Research Organization:
- Bhabha Atomic Research Centre, Bombay
- NSA Number:
- NSA-29-018572
- OSTI ID:
- 4345516
- Journal Information:
- Int. J. Radiat. Biol., v. 24, no. 6, pp. 631-635, Journal Name: Int. J. Radiat. Biol., v. 24, no. 6, pp. 631-635; ISSN IJRBA
- Country of Publication:
- United Kingdom
- Language:
- English
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Related Subjects
*IMIDES-- RADIOSENSITIVITY EFFECTS
*ORGANIC NITROGEN COMPOUNDS-- RADIOSENSITIVITY EFFECTS
*POTASSIUM IODIDES-- RADIOSENSITIVITY EFFECTS
*RADIOSENSITIZERS-- CHEMICAL REACTIONS
*SODIUM IODIDES-- RADIOSENSITIVITY EFFECTS
ANOXIA
DILUTION
ESCHERICHIA COLI
IODINE 131
N48310* --Life Sciences--Radiation Effects on Microorganisms- -Basic Studies
RADIOACTIVITY
RADIOSENSITIVITY
RESPONSE MODIFYING FACTORS
SCAVENGING
SYNERGISM
TIME DEPENDENCE