EFFECT OF SUCCESSIVE X-IRRADIATION ON
            <i>NOCARDIA CORALLINA</i>

Clark, J. B.; Webb, Robert B.

doi:10.1128/jb.74.1.26-30.1957

Cited by 9 publications

(9 citation statements)

References 7 publications

(6 reference statements)

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“…Repeated irradiation of N. corallina with ultraviolet light yielded results that were equivalent with those previously reported with X-irradiation (Clark and Webb, 1957). Dose-survival curves of the parent coccoids of N. corallina for both X-ray and ultraviolet light are of the multievent or sigmoid type.…”

Section: Resultssupporting

confidence: 84%

“…Survival of Nocardia corallina coccoids at a constant X-ray dose after successive ultraviolet treatments. found previously (Clark and Webb, 1957). This included an increase in ultraviolet-resistant cells, which have been isolated and found to be resistant to both ultraviolet and X-radiation (Clark and Frady, 1959).…”

Section: [Vol 80mentioning

confidence: 69%

“…The parent culture of N. corallina yields a multihit survivor response from both X rays and ultraviolet light. As shown by Clark and Webb (1957), this response changes, becoming much more sensitive to low doses of X rays after successive irradiation. This response to X rays was interpreted as an exponential, or single-hit, type of dose-survival curve although a radiation-resistant fraction of about 30 per cent was present after three successive irradiation treatments.…”

Section: Discussionmentioning

confidence: 97%

“…Four-day-old coccoid cultures were used for all irradiation experiments. Prior to irradiation, cell suspensions were made according to the technique described previously (Clark and Webb, 1957). Before irradiation all suspensions were examined microscopically and were not used unless the suspension contained at least 90 per cent single coccoidal cells.…”

Section: Methodsmentioning

confidence: 99%

“…Ultraviolet irradiation was done with a Will Corporation low pressure mercury vapor lamp which had an intensity of 200 Mw/in2 at a distance of 7 inches. The technique of X-irradiation was the same as that described previously (Clark and Webb, 1957). The ultraviolet irradiations were carried out on cell suspensions which had been appropriately diluted and surfaceplated on nutrient agar.…”

Section: Methodsmentioning

confidence: 99%

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OVERLAP OF SITE OF ACTION OF X-RAY AND ULTRAVIOLET IRRADIATION IN NOCARDIA CORALLINA

Clark

Webb

1960

J Bacteriol

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It is generally conceded that the terminal actions of X-ray and ultraviolet irradiation are mediated through different mechanisms (Hollaender, 1954, 1955). Some differences in the cytological and genetical effects of the two irradiations have been found (see Swanson and Stadler, 1955, for review). However, there is accumulating evidence that there is at least an overlap between the terminal sites of action of the two radiations. Ultraviolet light has been found to have a suppressive effect on X-ray damage in yeast by Sarachek and Lucke (1953) and by Elkind and Sutton (1958, 1959), on chromosome breaks in Tradescantia pollen tubes (Swanson, 1944), and in Drosophilia sperm by Kaufmann and Hollaender (1946). This suppressive effect has been interpreted as indicative of site overlap by Elkind and Sutton (1959). Also, in comparisons of haploid and diploid strains of yeast, Uretz (1955) found evidence that, at least to an appreciable extent, the sensitive sites in the cell which are involved in both X-ray and ultraviolet irradiation are the same. The increase in X-ray sensitivity of the progeny of X-irradiated coccoids of Nocardia corallina (Clark and Webb, 1957) offers an additional approach for testing of a possible overlap of terminal sites of action of X-ray and ultraviolet irradiations. Repeated X-ray treatments of N. corallina, with several growth cycles occurring between treatments resulted in a substantial increase in sensitivity to X rays. If ultraviolet light should cause similar results, or if populations with induced sensitivity to one ' This work was supported in part by grants from the Atomic Energy Commission under contract no. AT-(40-1)-1976, by the Faculty

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Section: Resultssupporting

confidence: 84%

Section: [Vol 80mentioning

confidence: 69%

Section: Discussionmentioning

confidence: 97%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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