Effect of long ultraviolet and short visible radiation (3500 to 4900Å) on escherichia coli

105

Abstract— In stationary phase, strains of Escherichia coli deficient in excision (B/r Her) or recombination repair (K.12 AB2463) were more sensitive than a repair proficient strain (B/r) to monochromatic near‐ultraviolet (365 nm) and visible (460 nm) radiations. The relative increase in sensitivity of mutants deficient in excision or recombination repair, in comparision to the wildtype, was less at 365 nm than at 254 nm. However, a strain deficient in both excision and recombination repair (K12 AB2480) showed a large, almost equal, increase in sensitivity over mutants deficient in either excision or recombination repair at 365 nm and 254 nm. All strains tested were highly resistant to 650 nm radiation. Action spectra for lethality of strains B/r and B/r Her in stationary phase reveal small peaks or shoulders in the 330–340, 400–410 and 490–510 nm wavelength ranges. The presence of 5μg/ml acriflavine (an inhibitor of repair) in the plating medium greatly increased the sensitivity of strain B/r to radiation at 254, 365 and 460 nm, while strains E. coli B/r Her and K12 AB2463 were sensitized by small amounts. At each of the wavelengths tested, acriflavine in the plating medium had at most a small effect on E. coli K.12 AB2480. Acriflavine failed to sensitize any strain tested at 650 nm. Evidence supports the interpretation that lesions induced in DNA by 365 nm and 460 nm radiations play the major role in the inactivation of E. coli by these wavelengths. Single‐strand breaks (or alkali‐labile bonds), but not pyrimidine dimers are candidates for the lethal DNA lesions in uvrA and repair proficient strains. At high fluences lethality may be enhanced by damage to the excision and recombination repair systems.

Section: Response At 365 Nmmentioning

confidence: 97%

SENSITIVITY OF STRAINS OF ESCHERICHIA COLI DIFFERING IN REPAIR CAPABILITY TO FAR UV, NEAR UV AND VISIBLE RADIATIONS*

Webb

Brown

1976

105

“…This observation is consistent with previous results, suggesting the inactivating lesions induced by NUV and FUV are dissimilar (Tuveson and Jonas, 1979;Tuveson, 1980). Hollaender (1943) reported that LH (in saline) of NUV-treated cells resulted in a decline in cell viability, while Eisenstark (1971) found no effect of LH on NUV-treated E. coli cells. Peak (1970) reported that NUV-treated E. coli cells exhibited LHR.…”

Section: -4mentioning

confidence: 99%

“…When NUV-treated cells are held at relatively high densities (108-109 cells/m/), damaged cells may lyse releasing nutrients which allow growth of undamaged survivors in non-nutrient suspending medium. At relatively low cell densities (perhaps 5 x 10' cells/m/ or less as used by Hollaender, 1943), damaged cells may not release sufficient nutrients to allow significant multiplication of undamaged survivors.…”

Section: -4mentioning

confidence: 99%

“…The results of liquid holding (LH) following FUV treatment have been assumed to be an expression of dark repair functions. Liquid holding following near-UV (NUV, 300400nm) treatment of E. coli cells can result in a decline in (Hollaender, 1943), no effect on (Eisenstark, 1971), or an enhancement of (Peak, 1970) survival. In this paper, data are described which show that strains differing in their sensitivity to inactivation by NUV (Tuveson and Jonas, 1979), sunlight and photodynamic killing (Tuveson and March, 1980), as well as FUV sensitivity (Tuveson and Jonas, 1979) although appearing to show enhanced survival with LH, are in fact incapable of LHR in saline following NUV treatment.…”

Section: Introductionmentioning

confidence: 99%

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THE EFFECTS OF LIQUID HOLDING ON NEAR‐UV(300–400 nm) IRRADIATED ESCHERICHIA COLI STRAINS DIFFERING IN NEAR AND FAR‐UV RADIATION SENSITIVITY

Tuveson

Violante

1982

Abstract— Stationary phase cells from four Escherichia coli strains differing in near‐ (nur vs. nur +) and far‐UV (recAl vs. recA+) radiation sensitivity were subjected to near‐UV radiation (NUV) in 0.85% saline. Although the NUV‐irradiated cultures yielded increased colony numbers following 24 h of liquid holding (LH), a fluctuation test for each experiment showed that the observed increases were not due to recovery but were in fact due to cell multiplication. The decline in viability observed after NUV with liquid holding using the fluctuation test was equivalent in strains RT2, 3 and 4 while the decline observed with RT1 was less marked. The discrepancy between LH involving cell densities of 108‐109 and 1–4 cells/m/ can be resolved by assuming that with dense cell suspensions, NUV‐induced membrane damage leads to leakage or lysis, supplying sufficient nutrients to allow growth of undamaged, surviving cells.

“…The deleterious effects of near-W and visible light such as growth delay, mutagenesis, carcinogenesis and lethality (Pollard, 1974;Hollaender, 1943) is amenable to repair in bacterial and animal cells (Ramabhadran and Jagger, 1974; Webb and Lorentz, 1970; Chatterjee and Bhattacharjee, 1975). In bacteria, recombination is involved in the repair of damage induced by these radiations (Eisenstark, 1970;Gopalakrishna and Bhattacharjee, 1976).…”

Section: Introductionmentioning

confidence: 99%

Synergistic Interaction Between the Tryptophan Photoproducts and Near‐ultraviolet Light in Amoeba

Bhattacharjee

Chatterjee

1977

Abstract. Both S‐ and G2‐phase cells of amoeba are found to be sensitized by coirradiation of cells with Tryptophan (Trp). At a fluence of 1.5 times 105 Jm‐2 to which G2 phase cells are resistant, they show a drastic (8‐fold) increase in sensitivity when irradiated in 0.5% Trp solution. Freshly irradiated Trp solution is found to be lethal to G2 cells that have received a sublethal fluence of near‐UV light. Irradiated Trp, however, does not kill unirradiated amoeba. Nuclear transplantation experiments have shown that the lethality of cells when coirradiated with Trp is due to damage located predominantly in the cytoplasm. It is suggested that sublethal fluence of near‐UV light makes the cells “leaky” to the toxic photooxidation products of Trp solution.