Radiation Synergism and Antagonism

Tyrrell, Rex M.

doi:10.1007/978-1-4684-2580-2_2

Cited by 37 publications

(9 citation statements)

References 166 publications

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“…For example, inhibition has been observed at very high doses of UV-A (27) and through synergistic effects between two UV-A wavelengths (26). Inhibition of repair might reflect the specific ability of UV-A to induce irreversible physiological changes, including metabolic inhibition (25). Based on the results from this study, there may be synergistic effects between a number of wavelengths emitted by medium-pressure lamps that do not occur with low-pressure lamps.…”

Section: Discussionmentioning

confidence: 81%

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Potential Repair of Escherichia coli DNA following Exposure to UV Radiation from Both Medium- and Low-Pressure UV Sources Used in Drinking Water Treatment

Zimmer¹,

Slawson

2002

Appl Environ Microbiol

191

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The increased use of UV radiation as a drinking water treatment technology has instigated studies of the repair potential of microorganisms following treatment. This study challenged the repair potential of an optimally grown nonpathogenic laboratory strain of Escherichia coli after UV radiation from low-and mediumpressure lamps. Samples were irradiated with doses of 5, 8, and 10 mJ/cm 2 from a low-pressure lamp and 3, 5, 8, and 10 mJ/cm 2 from a medium-pressure UV lamp housed in a bench-scale collimated beam apparatus. Following irradiation, samples were incubated at 37°C under photoreactivating light or in the dark. Sample aliquots were analyzed for up to 4 h following incubation using a standard plate count. Results of this study showed that E. coli underwent photorepair following exposure to the low-pressure UV source, but no repair was detectable following exposure to the medium-pressure UV source at the initial doses examined. Minimal repair was eventually observed upon medium-pressure UV lamp exposure when doses were lowered to 3 mJ/cm 2 . This study clearly indicates differences in repair potential under laboratory conditions between irradiation from low-pressure and medium-pressure UV sources of the type used in water treatment.

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Section: Discussionmentioning

confidence: 81%

“…Other researchers have previously reported inhibition of repair from specific wavelengths of UV (25,26,27). For example, inhibition has been observed at very high doses of UV-A (27) and through synergistic effects between two UV-A wavelengths (26).…”

Section: Discussionmentioning

confidence: 89%

Potential Repair of Escherichia coli DNA following Exposure to UV Radiation from Both Medium- and Low-Pressure UV Sources Used in Drinking Water Treatment

Zimmer¹,

Slawson

2002

Appl Environ Microbiol

191

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“…Exposure to either monochromatic 365 nm radiation (reviewed by Tyrrell, 1978) or broad-band NUV (Hartman and Eisenstark, 1980) resulted in a reduced capacity to repair DNA. This NUV-mediated destruction can be manifested in an increased sensitivity to other deleterious agents, including FUV.…”

Section: Resultsmentioning

confidence: 99%

IN SITU HYDROGEN PEROXIDE PRODUCTION MAY ACCOUNT FOR A PORTION OF NUV (300–400 nm) INACTIVATION OF STATIONARY PHASE Escherichia coli

Hartman

1986

Photochem & Photobiology

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Abstract— Pre‐irradiation of stationary phase cells of Escherichia coli K‐12 with broadband near‐UV radiation potentiates the lethal effects of subsequent exposure to near‐UV radiation plus hydrogen peroxide. Identical fluences failed to modulate killing due to far‐UV radiation. These data indicate that biologically revelant levels of hydrogen peroxide may be generated in situ upon the near‐UV irradiation of cells.

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“…A recent study (Keyse et al, 1983) describes the action spectra for killing human fibroblasts out to a wavelength of 365 nm. As for several bacterial (see Peak and Peak, 1982) and repair deficient bacteriophage and bacterial spore (Tyrrell, 1978a) strains, the action spectra show an abrupt decrease in slope at wavelengths longer than 320 nm. In the present study, we have used a human lymphoblastoid cell-line to extend the action spectra for inactivation out to 434 nm and, in particular, we have addressed the question as to whether lethal interactions occur between different wavelength regions in the UV and blue-violet visible range.…”

Section: Introductionmentioning

confidence: 89%

“…Long wavelength UV may protect bacteria from (see Jagger, 1983 for review) or sensitize (Tyrrell and Webb, 1973;reviewed by Webb, 1977 andTyrrell, 1978b) them to shorter wavelength UV according to the wavelength, conditions and bacterial strain employed. We have therefore systematically searched for the existence of similar phenomena using the repair proficient human lymphoblastoid cell line.…”

Section: Lethal Interactions Between Long (334 365 405 Nm) and Shormentioning

confidence: 99%

Lethal Action of Ultraviolet and Visible (Blue‐violet) Radiations at Defined Wavelengths on Human Lymphoblastoid Cells: Action Spectra and Interaction Sites

Tyrrell¹,

Werfelli²,

Moraer

1984

Photochem & Photobiology

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The repair proficient human lymphoblastoid line (TK6) has been employed to construcr an action spectrum for the lethal action of ultraviolet (UV) radiation in the range 254-434 nm and to examine possible interactions between longer (334, 365 and 405 nm) and shorter wavelength (254 and 313 nm) radiations. The action spectrum follows a DNA absorption spectrum fairly closely out to 360 nm. As in previously determined lethal action spectra for procaryotic and eucaryotic cell populations. there is a broad shoulder in the 334-405 nm region which could reflect the existence of either (a) a non-DNA chromophore or (b) a unique photochemical reaction in the DNA over this region. Pre-treatment with radiation at 334 or 365 nm causes either a slight sensitivity to (low fluences) or protection from (higher fluences) subsequent exposure to radiation at a shorter wavelength (254 or 313 nm). Pre-irradiation at a visible wavelength (405 nm) at all fluence levels employed sensitizes the populations to treatment with 254 or 313 nm radiations. These interactions will influence the lethal outcome of cellular exposure to broad-band radiation sources.

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Radiation Synergism and Antagonism

Cited by 37 publications

References 166 publications

Potential Repair of Escherichia coli DNA following Exposure to UV Radiation from Both Medium- and Low-Pressure UV Sources Used in Drinking Water Treatment

Potential Repair of Escherichia coli DNA following Exposure to UV Radiation from Both Medium- and Low-Pressure UV Sources Used in Drinking Water Treatment

IN SITU HYDROGEN PEROXIDE PRODUCTION MAY ACCOUNT FOR A PORTION OF NUV (300–400 nm) INACTIVATION OF STATIONARY PHASE Escherichia coli

Lethal Action of Ultraviolet and Visible (Blue‐violet) Radiations at Defined Wavelengths on Human Lymphoblastoid Cells: Action Spectra and Interaction Sites

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