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Hartley-Asp B. Enhancement by methylated oxypurines of the frequency of induced chromosomal aberrations. IV. The dependence of the potentiation on the type of material. Hereditas 2009; 83:223-36. [PMID: 824245 DOI: 10.1111/j.1601-5223.1976.tb01587.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
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Abstract
Exponentially growing cells of the PtK-2 line (ATCC No. CCL56, from the marsupial Potorous tridactylus) require protein and RNA synthesis in a limited period following UV-radiation damage for optimal recovery as colony formers [Overberg et al. (1988) Mutat. Res. 194, 83-92]. Overall behavior suggests the operation of damage-induced recovery processes. The capacity of confluent cell monolayers for infection with unirradiated herpes simplex virus 1 (HSV-1) is sharply reduced by UV-irradiation. We have followed capacity changes in exponentially growing cells after irradiation and varying amounts of photoreactivation by means of an infectious center assay. These changes closely parallel changes of colony formation. Spontaneous recovery of capacity in the dark occurs over approximately the same time period that the UV sensitivity of colony formation depends on macromolecular synthesis. The effect of photoreactivation is complementary rather than additive to this recovery, suggesting that the dark recovery in this period concerns pyrimidine dimers in cell DNA.
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Cleaver JE. Caffeine toxicity is inversely related to DNA repair in simian virus 40-transformed xeroderma pigmentosum cells irradiated with ultraviolet light. TERATOGENESIS, CARCINOGENESIS, AND MUTAGENESIS 1989; 9:147-55. [PMID: 2570469 DOI: 10.1002/tcm.1770090303] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Human cells transformed by simian virus 40 (SV40) are more sensitive to killing by ultraviolet light when grown in caffeine after irradiation. The degree of sensitization at 2 mM caffeine (expressed as the ratio of the 37% survival dose for control cells divided by the 37% survival dose for cells grown in caffeine, i.e., the dose modification factor) was approximately 1.9 in transformed normal cells and 3.8-5.8 in excision-defective xeroderma pigmentosum (XP) groups A, C, and D cells. A large dose modification factor of 12 was observed in a transformed XP variant cell line. Chinese hamster ovary cells were not significantly different from transformed normal human cells, with a maximum dose modification factor of 1.5. Two radioresistant XP revertants that do not excise cyclobutane dimers gave different responses; one resembled its group A parent in being sensitized by caffeine, and one did not. These results can be interpreted on the basis of a single hypothesis that cells are killed as a result of attempts to replicate damaged DNA. Increased replication rates caused by transformation, increased numbers of replication forks in DNA caused by caffeine, and increased numbers of damaged sites ahead of replication forks in excision-defective cells are all processes that will consequently increase killing according to this hypothesis. A corollary is that the XP variant may be highly sensitized to caffeine because of excision defects at the DNA replication forks, an idea that may be important in designing cloning strategies for the XP variant gene.
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Affiliation(s)
- J E Cleaver
- Laboratory of Radiobiology and Environmental Health, University of California, San Francisco 94143-0750
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Das BC. Factors that influence formation of sister chromatid exchanges in human blood lymphocytes. Crit Rev Toxicol 1988; 19:43-86. [PMID: 3056658 DOI: 10.3109/10408448809040817] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Sister chromatid exchange (SCE) reflects an interchange of DNA sequences between helices in a replicating chromosome. This was initially accomplished by Taylor and colleagues (1957) using tritiated thymidine incorporation followed by autoradiography. The development of an elegant technique for differential staining of sister chromatids by incorporating a thymidine analog, 5-bromodeoxyuridine (BrdU) has greatly simplified the detection of SCEs in metaphase chromosomes. In recent years, the analysis of SCE has been considered to be a highly sensitive and additional (i.e., with chromosome aberrations) end point for measuring mutagenic/carcinogenic potential of various environmental agents and is increasingly being used to detect and differentiate among chromosome fragility human diseases that predispose to neoplasia. Attention has been focused to see if the induction of SCEs in lymphocyte cultures can be used as a reliable "biological dosimeter" for genetic risk assessment and to monitor the exposed populations. Several physical or preparatory as well as biological factors that modify the response and formation of SCEs make the monitoring difficult. The purpose of this article is to review and analyze these factors to facilitate an effective development of a standard protocol for SCE testing and for appropriate evaluation of test results. This may also provide clues to understand the yet unknown molecular mechanism(s) and biological significance of SCE formation.
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Affiliation(s)
- B C Das
- Molecular Oncology Division, Indian Council of Medical Research, New Delhi
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Andrae U, Singh J, Ziegler-Skylakakis K. Pyruvate and related alpha-ketoacids protect mammalian cells in culture against hydrogen peroxide-induced cytotoxicity. Toxicol Lett 1985; 28:93-8. [PMID: 4071565 DOI: 10.1016/0378-4274(85)90015-3] [Citation(s) in RCA: 131] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Pyruvate efficiently protected V79 Chinese hamster cells against the lethal effects of hydrogen peroxide. Protection was also provided by other alpha-ketoacids, such as alpha-ketobutyrate, alpha-ketoglutarate and alpha-ketoadipate, although higher concentrations were required. The corresponding beta-ketoacids had no effect. The results indicate that pyruvate and other alpha-ketoacids possess antioxidant activity in vitro and, probably, in vivo.
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Abstract
A quantitative hypothesis is developed, analogous to a previously developed model for ionising radiation, to describe the induction of eukaryotic cell killing by ultraviolet light. The hypothesis makes use of a recent proposal which suggests that pairs of dimers close to, and on either side of, a replication termination site provide long-lived blocks to replication, by suggesting that these 'paired dimer' lesions are potentially lethal. The hypothesis contains two crucial elements: (i) two dimers form the crucial lesion, and (ii) the paired dimer lesion is only recognised at the DNA-replication subsequent to exposure. Cell survival is predicted to be related to the square of the UV exposure and several sets of data are shown to be in good agreement with this prediction for surviving fractions down to 5% at least. It is shown that making use of a known molecular repair process, excision repair, the hypothesis gives a logical explanation for the unusual effects of UV fractionation reported previously for both exponentially growing cells and also for stationary cells. The hypothesis is amenable to further experimental verification.
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Abstract
A comprehensive investigation has been made of photoreactivation of UV damage in cells cultured from the fat-tailed marsupial mouse, Sminthopsis crassicaudata. Maximal photoreversal of the lethal effects of germicidal UV radiation was obtained by exposure of cells to intense fluorescent black light at 37 degrees C. Dose-reduction factors of approximately 2 were obtained. This phenomenon was shown to be a true photoreactive not a photoprotective effect. Attempts to photoreverse the lethal effects of UV light by using white fluorescent light, or black lights at lower temperatures, proved ineffectual. Photoreactivation with black light at 37 degrees C for 30 min effectively photoreversed UV-induced pyrimidine dimers and also substantially reduced the levels of UV-induced DNA-repair replication. Sunlight was also found to be an effective source of photoreactivating light. Although a reasonable correlation was found between the lethal effects of UV light and the number of pyrimidine dimers persisting unrepaired in cellular DNA, some experiments did suggest that either a small subclass of dimers or some type of non-dimer damage contributed significantly to overall lethality. Two of the effects induced by UV light could not, however, be reversed by black light. These were sister-chromatid exchanges and the inhibition of DNA synthesis. The conclusion was reached that either these effects reflect non-dimer (non-photoreactivable damage) or that, under appropriate growth conditions, some damage rapidly disrupts the DNA, say within a replicon, in a manner which cannot be reversed even when the primary lesion has been subsequently removed.
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Wade MH, Trosko JE. Enhanced survival and decreased mutation frequency after photoreactivation of UV damage in rat kangaroo cells. Mutat Res 1983; 112:231-43. [PMID: 6888409 DOI: 10.1016/0167-8817(83)90009-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The effect of pyrimidine dimers on cytotoxicity, DNA repair and mutagenesis was studied in cells, derived from the rat kangaroo, which possess photoreactivating capabilities. A significant enhancement in colony-forming ability was achieved after UV irradiation in exponentially growing cells if photoreactivating light treatment followed the UV irradiation. If photoreactivation treatment was delayed 24 h after UV irradiation, no significant increase in survival was observed. Assays of pyrimidine dimers, unscheduled DNA synthesis, and survival in contact-inhibited cells all confirmed a minor role of dark excision repair and a major role of photoreactivation. Photoreactivation decreased the frequency of mutations to 6-thioguanine resistance to a greater extent than the alteration seen in survival. Approximately 1.6 times the dose must be given to get equal killing in photoreactivated cells, whereas 4 times the dose must be given to obtain equal mutation frequencies in light-treated cells. This suggests that the removal of dimers is more effective in mutant reduction than enhancement of survival.
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Ishizaki K, Nikaido O, Takebe H. PHOTOREACTIVATION OF ULTRAVIOLET LIGHT-INDUCED SISTER CHROMATID EXCHANGES IN POTOROUS CELLS. Photochem Photobiol 1980. [DOI: 10.1111/j.1751-1097.1980.tb03718.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Chiang T, Rupert CS. Action spectrum for photoreactivation of ultraviolet-irradiated marsupial cells in tissue culture. Photochem Photobiol 1979; 30:525-8. [PMID: 504359 DOI: 10.1111/j.1751-1097.1979.tb07173.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Jackson JF, Linskens HF. Pollen DNA repair after treatment with the mutagens 4-nitroquinoline-1-oxide, ultraviolet and near-ultraviolet irradiation, and boron dependence of rapair. ACTA ACUST UNITED AC 1979. [DOI: 10.1007/bf00334289] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Freed JJ, Hoess RH, Angelosanto FA, Massey HC. Survival and DNA repair in ultraviolet-irradiated haploid and diploid cultured frog cells. Mutat Res 1979; 62:325-39. [PMID: 315517 DOI: 10.1016/0027-5107(79)90088-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Survival and repair of DNA following ultraviolet (254-nm) radiation have been investigated in ICR 2A, a cultured cell line from haploid embryos of the grassfrog, Rana pipiens. Survival curves from cells recovering in the dark gave mean lethal dose value (Do) in the range 1.5--1.7 Jm-2 for both haploid and diploid cell stocks. The only significant difference observed between haploids and diploids was in the extent of the shoulder at low fluence (Dq), the value for exponentially multiplying diploid cells (3.0 Jm-2) being higher than that found for haploids (1.2 Jm-2). Irradiation of cultures reversibly blocked in the G1 phase of the cell cycle gave survival-curve coefficients indistinguishable between haploids and diploids. Post-irradiation exposure to visible light restored colony-forming capacity and removed chromatographically estimated pyrimidine dimers from DNA at the same rates. After fluences killing 90% of the cells, complete restoration of survival was obtained after 60-min exposure to 500 foot-candles, indicating that in this range lethality is entirely photoreversible and therefore attributable to pyrimidine dimers in DNA. Dimer removal required illumination following ultraviolet exposure, intact cells and physiological temperature, implying that the photoreversal involved DNA photolyase activity. Excision-repair capacity was slight, since no loss of dimers could be detected chromatographically during up to 48 h incubation in the dark and since autoradiographically detected "unscheduled DNA synthesis" was limited to a 2-fold increase saturated at 10 Jm-2. These properties make ICR 2A frog cells useful to explore how DNA-repair pathways influence mutant yield.
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Schroy CB, Todd P. Anomalous dose-response characteristics induced by caffeine in ultraviolet-irradiated V79--79 Chinese hamster cells. Photochem Photobiol 1979; 30:305-8. [PMID: 504354 DOI: 10.1111/j.1751-1097.1979.tb07152.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Fu Y, Lange CS, Miller MW. The absence of an effect of photoreactivation on sub-lethal damage accumulation in a photoreactive wallaby cell-line. INTERNATIONAL JOURNAL OF RADIATION BIOLOGY AND RELATED STUDIES IN PHYSICS, CHEMISTRY, AND MEDICINE 1978; 34:73-9. [PMID: 309444 DOI: 10.1080/09553007814550641] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Monolayer cultures of JU56 wallaby cells were exposed to germicidal U.V. and/or photoreactivating (PR) light. The U.V. exposures induced dose-dependent cell-death. The survival data are consistent with a common extrapolation number (n) of 6 x 17 +/- 0 x 98 with a D(0) of 123 x 0 +/- 6 x 8 erg/mm2 for photo-reactivated cells and a D0 of 87 x 3 +/- 4 x 9 erg/mm2 for non-photoreactivated cells; the photoreactivation protected the cells with a dose-modification factor of 1 x 41 +/- 0 x 02. Therefore PR is not a shoulder phenomenon and so has no relationship to the repair of sub-lethal damage.
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Harm H. Damage and repair in mammalian cells after exposure to non-ionizing radiations. I. Ultraviolet and visible light irradiation of cells of the rat kangaroo (Potorous tridactylus) and determination of photorepairable damage in vitro. Mutat Res 1978; 50:353-66. [PMID: 672919 DOI: 10.1016/0027-5107(78)90040-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Hsie AW, Li AP, Machanoff R. A fluence response study of lethality and mutagenicity of white, black, and blue fluorescent light, sunlamp, and sunlight irradiation in Chinese hamster ovary cells. Mutat Res 1977; 45:333-42. [PMID: 593289 DOI: 10.1016/0027-5107(77)90143-9] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Under a set of defined experimental conditions, the fluence response of Chinese hamster ovary (CHO) cells to various light sources was studied by measuring single-cell survival and mutation to 6-thioguanine (TG) resistance. Fluorescent white, black, and blue lights were sightly lethal and mutagenic. Sunlamp light was highly lethal and mutagenic, exhibiting these biological effects within 15 sec of exposure under conditions recommended by the manufacturer for human use. Lethal and mutagenic effects were observed after 5 min of sunlight exposure; responses varied with hourly and daily variations in solar radiation. Sunlight-induced TG-resistant variants possessed less than 5% of parental cellular hypoxanthine--guanine phosphoribosyl transferase (HGPRT) enzyme activity, suggesting that the mutation induction occurs at this locus. The cell survival and mutation-induction curves generated by exposure of cells to both sunlamp and sunlight were similar to those obtained by the use of a standard far-UV lamp.
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Kato H. Spontaneous and induced sister chromatid exchanges as revealed by the BUdR-labeling method. INTERNATIONAL REVIEW OF CYTOLOGY 1977; 49:55-97. [PMID: 324942 DOI: 10.1016/s0074-7696(08)61947-6] [Citation(s) in RCA: 181] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Abstract
Cultured cells (line PtK-2) from the marsupial mammal rat-kangaroo, or potoroo (Potorous tridactylis), which photoreactivate (PR) both UV-induced dimers and lethality, excise few dimers, and are only slightly sensitized by post-UV exposure to caffeine, were subjected to caffeine and hydroxyurea (HU) treatments during the 30-min PR period. It was found that neither caffeine nor HU inhibited PR of lethality as measured by colony-forming ability. Further, the cells exhibited no photoprotective properties and 3 mM caffeine potentiated the same slight survival decrease in both photoreactivated and unphotoreactivated cells. It is evident that caffeine does not inhibit PR or the survival-related dark repair systems to any great extent, and hence the caffeine-sensitive post-UV dark repair found in this (and possibly other) mammalian cell lines may not be related directly to survival-dependent pyrimidine dimer removal, but instead to lesions or repair processes other than, but not excluding, pyrimidine dimers.
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Affiliation(s)
- C B Schroy
- Department of Biochemistry and Biophysics, Pennsylvania State University, University Park, PA 16802, USA
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Lytle CD, Benane SG, Stafford JE. Host cell reactivation in mammalian cells. V. Photoreactivation studies with herpes virus in marsupial and human cells. Photochem Photobiol 1976; 23:331-6. [PMID: 180551 DOI: 10.1111/j.1751-1097.1976.tb07257.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Lieberman MW. Approaches to the analysis of fidelity of DNA repair in mammalian cells. INTERNATIONAL REVIEW OF CYTOLOGY 1976; 45:1-23. [PMID: 783064 DOI: 10.1016/s0074-7696(08)60076-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Thayer PS, Palm PE. A current assessment of the mutagenic and teratogenic effects of caffeine. CRC CRITICAL REVIEWS IN TOXICOLOGY 1975; 3:345-69. [PMID: 1097193 DOI: 10.3109/10408447509079863] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Lytle CD, Benane SG. Letter: Effect of photoreactivating light on virus infection of UV-exposed Potorro cells. INTERNATIONAL JOURNAL OF RADIATION BIOLOGY AND RELATED STUDIES IN PHYSICS, CHEMISTRY, AND MEDICINE 1975; 27:487-91. [PMID: 168163 DOI: 10.1080/09553007514550481] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Wang RJ. Lethal effect of "daylight" fluorescent light on human cells in tissue-culture medium. Photochem Photobiol 1975; 21:373-5. [PMID: 1208665 DOI: 10.1111/j.1751-1097.1975.tb06688.x] [Citation(s) in RCA: 83] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Stoien JD, Wang RJ. Effect of near-ultraviolet and visible light on mammalian cells in culture II. Formation of toxic photoproducts in tissue culture medium by blacklight. Proc Natl Acad Sci U S A 1974; 71:3961-5. [PMID: 4530275 PMCID: PMC434306 DOI: 10.1073/pnas.71.10.3961] [Citation(s) in RCA: 102] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Near-ultraviolet radiation was found to be lethal for mammalian cells in Dulbecco's modified Eagle's medium without serum or phenol red. Irradiation of the cells with near-ultraviolet light while the cells were in phosphate-buffered-saline abolished the lethal effect. When only the medium was irradiated followed by the addition of unirradiated cells and serum, the cells were still killed. The photoactive components of the medium for this effect were riboflavin, tryptophan, and tyrosine. When riboflavin was deleted from the medium being irradiated and added later, almost no killing was detected. Irradiation of salt solution of riboflavin and tryptophan or riboflavin and tyrosine, resulted in cell killing. Little or no killing resulted when riboflavin, tryptophan, or tyrosine was irradiated singly. The formation of photoproducts toxic for mammalian cells appears to involve photodynamic action. Experiments utilizing Dulbecco's or similar media without proper controls may produce anomalous results from light illuminating the laboratory.
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