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Swenson, L.W.; Mohindra, R.K.

doi:10.1103/physrev.150.877

Cited by 20 publications

(2 citation statements)

References 24 publications

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“…Favre (1980) The strains are listed according to the dose reduction factor measured in a typical photoprotection experiments. The (Swenson, 1976;Swenson ef al., 1975)l. The isogenic B/r strain lacking Cthiouridine in its tRNA (S4Urd-) does not exhibit PP (Tsai and Jagger, 1981).…”

Section: Discussionmentioning

confidence: 99%

THE Ion GENE AND PHOTOPROTECTION IN Escherichia coli K‐12

Waksman¹,

Thomas²,

Favre³

1984

Photochem & Photobiology

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Abstract— Photoprotection i. e. the increased resistance of the cells preilluminated with near ultraviolet light (300–380 nm) to the lethal action of 254 nm radiations is observed in wild‐type Escherichia coli B cells (which exhibits the Fil phenotype) but requires either an integrated prophage or a recA mutation to be detected in E. coli K12 strains. Here we have demonstrated that significant photoprotection occurs in an E. coli K12 recA+ cell containing the Ion allele which is responsible for filamentous growth (Fil phenotype) after 254 nm irradiation. The Fil phenotype can be suppressed by the sfiA of sfiB suppressor genes. Since the E. coli K12 recA+Ion sfiB strain exhibits no more photoprotection, these data support the conclusion that in Ion strains photoprotection is due to the abolition of the 254 nm induced filamentation by the near ultraviolet treatment. In addition, we show here that near ultraviolet illumination of the cells leads to a severe restriction of the bulk protein synthesis, as well as of the inducibility of β‐galactosidase and tryptophanase. These effects are observed only in nuv+ cells that contains 4‐thiouridine the chromophore responsible for photoprotection. We propose that in Ion (lysogenic) strains, photoprotection is due to prevention of the SOS response. During the growth lag, the low residual level of protein synthesis does not allow the induction of the SOS response and accordingly prevents filamentation (the lytic cycle). Concomitantly the SOS triggering signals are eliminated via DNA repair.

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Section: Discussionmentioning

confidence: 99%

THE Ion GENE AND PHOTOPROTECTION IN Escherichia coli K‐12

Waksman¹,

Thomas²,

Favre³

1984

Photochem & Photobiology

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“…In studying the recovery of the yeast from near-UV killing we used the same approach as for the study of the repair mechanisms in bacteria damaged by far-UV radiation (postincubation in a non-nutrient medium). The enhanced degree of survival resulting from this, known as 'liquid holding recovery', is associated with the operation of the dark repair system which repairs photochemical damage in DNA (Harm, 1966;Swenson and Setlow, 1966;Ganesan and Smith, 1969;Swenson, 1976). In the experiments, C. guillierrnondii was irradiated with the isoeffective doses of 313 and 254 nm radiation and then incubated for various times in a non-nutrient (mineral) medium before being inoculated on agar.…”

Section: -Nm-induced Yeast Inactivation and Their Recovery In Non-mentioning

confidence: 99%

REPAIR OF 313‐NM INDUCED LESIONS AND PHOTOPROTECTION IN YEAST CANDIDA GUILLIERMONDII

Fraikin

Pospelov

Rubin³

1977

Photochem & Photobiology

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Abstract. The present communication is concerned with the effects of near‐UV radiation (300–380 nm) on yeast Candida guilliermondii. It was found that certain doses of 313 nm irradiation caused inactivation of the yeast which was exhibited in a way different from the lethal action of far‐UV radiation. It was also found that the cells inactivated by 313 nm are capable of recovering vitality, if incubated for some time in a non‐nutrient medium. The yeast inactivated by far‐UV radiation also proved to be capable of recovering, though to a lesser degree. Both 334 nm radiation and non‐lethal doses at 313 nm induced the photoprotective effect against far‐UV damage. The effect was exhibited if there was a certain time interval (2–4 h) between the exposures to photoprotective light and subsequent far‐UV radiation. Within this time interval the extent of photoprotection was dependent on temperature.

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