List of Figures

Figure page

1 The partial reduction products of oxygen........................................... 2

2 The SOS regulon................................................................................... 23

3 The phototoxic spectrum...................................................................... 28

4 Structure of dyes.................................................................................... 31

5 Dye reactions.......................................................................................... 43

6 Cyanide sensitive and resistant respiration....................................... 58

7 Change in spectrum of azure c with addition of DNA..................... 62

8 Change in spectrum of methylene blue with addition of DNA....................................................................................................... 63

9 Change in spectrum of thionin with the addition of DNA............... 64

10 Change in spectrum of acridine orange with the addition of DNA................................................................................... 65

11 Change in spectrum of proflavin with the addition of DNA............ 66

12 Lack of change in spectrum of fluorescein with the addition of DNA.................................................................................... 67

13 Oxidation of 0.5 mM NADH by 1 mM thionin...................................... 69

14 Oxidation of 0.5 mM NADH by 1 mM rose bengal............................. 70

15 Oxidation of 0.5 mM NADH by 1 mM methylene blue....................... 71

16 Oxidation of 0.5 mM NADH by 1 mM azure c..................................... 72

17 Reduction of 20 mM cytochrome c mediated by 0.5 mM methylene blue..................................................................................... 74

18 Reduction of 20 mM cytochrome c mediated by 0.5 mM rose bengal......................................................................................... 75

19 Reduction of 20 mM cytochrome c mediated by 0.5 mM fluorescein............................................................................................ 76

20 Reduction of 20 mM cytochrome c mediated by 0.5 mM acridine orange............................................................................ 77

21 Reduction of 20 mM cytochrome c mediated by 0.5 mM proflavin................................................................................................ 78

22 Reduction of 20 mM cytochrome c mediated by 0.5 mM thionin.................................................................................................... 79

23 Reduction of 20 mM cytochrome c mediated by 0.5 mM azure c.................................................................................................... 80

24 Set-up of hydroxyl radical assay experiments................................ 84

25 Hydroxyl radical production mediated by ten dyes assayed with the salicylate assay.................................................................... 87

26 Hydroxyl radical production mediated by azure c and proflavin as a function of time............................................................ 89

27 Production of OH. increased as the concentration of dye increased...................................................................................... 90

28 Effectiveness of various substrates in the salicylate assay............. 91

29 Glutathione as a substrate for dye reduction with four dyes.......... 93

30 Effectiveness of various substrates in mediating OH. production.............................................................................................. 94

31 Increasing concentrations of iron and copper catalyzed increasing amounts of OH. formation............................................... 96

32 Chelators with and without iron in the salicylate assay................... 97

33 Comparison of DTPA with EDTA in the mediation of

OH. production by several dyes in the salicylate assay.................. 98

34 Ability of assorted substances to act as chelators in the thiobarbituric acid assay............................................................... 101

35 Ability of assorted substances to act as chelators in the salicylate assay.................................................................................... 102

36 DNA as a chelator in the azure c mediated production of OH. as detected by the salicylate assay..................................... 104

37 Production of OH. mediated by azure c in the presence or absence of EDTA or DNA........................................................... 105

38 Production of OH. mediated by DNA-intercalated azure c and methylene blue, as measured in the thiobarbituric acid assay................................................................... 106

39 Production of OH. mediated by DNA-intercalated proflavin, acridine orange, fluorescein, and methylene blue, as measured in salicylate assay.......................................................... 107

40 Production of OH. mediated by DNA-intercalated and non-intercalated methylene blue, neutral red, acridine orange, and fluorescein.................................................... 108

41 Competition between scavengers and salicylate in the salicylate assay....................................................................... 110

42 Azide as an OH. scavenger in the salicylate assay....................... 111

43 Substrate limitation in OH. production.............................................. 113

44 Hydroxyl radical scavengers prevent enhancement of OH. production by hydrogen peroxide as assayed with salicylate..................................................................................... 114

45 DNA strand scission by illumination of dyes in presence and absence of light......................................................... 119

46 Single-stranded scission of DNA by azure c.................................... 121

47 Nicking of DNA by thionin in vitro...................................................... 122

48 Nicking of DNA by toluidine blue o in vitro...................................... 123

49 Nicking of DNA by methylene blue in vitro....................................... 124

50 Nicking of DNA by acridine yellow in vitro........................................ 126

51 Nicking of DNA by acridine orange in vitro....................................... 127

52 Nicking of DNA by proflavin in vitro.................................................... 128

53 Nicking of DNA by rose bengal in vitro........................................... 129

54 Nicking of DNA by fluorescein in vitro. ............................................ 130

55 Nicking of DNA by lucifer yellow in vitro.......................................... 131

56 Nicking of DNA by hematoporphyrin derivative in vitro. .................................................................................................... 132

57 Nicking of DNA by quinacrine in vitro............................................ 133

58 Nicking of DNA by increasing concentrations of azure c in vitro.................................................................................. 134

59 Prevention of azure c mediated nicking of DNA by increasing concentrations of DMSO in vitro.................. 135

60 Exacerbation of azure c mediated nicking of DNA by increasing concentrations of FeCl3 in vitro.................... 136

61 Nicking of DNA in the presence of different metals and chelators............................................................................................. 138

62 Abilities of several substances to act as oxidizable substrates in azure c mediated nicking of DNA in vitro.............. 140

63 Nicking of DNA by several dyes in the presence and absence of NADH and of the scavenger DMSO in vitro............ 141

64 Increasing concentrations of substrates have increasing effects............................................................................... 143

65 Nicking of DNA by several dyes in the presence of NADH, tryptophan, tyrosine, or no reductant in vitro............... 145

66 Nicking of DNA by several dyes in the presence and absence of GTP in vitro..................................................................... 146

67 Substitution of GTP for NADH in the rose bengal mediated nicking of DNA in vitro..................................................... 147

68 Ability of dGMP to act as oxidizable substrate for rose bengal and azure c mediated nicking of DNA in vitro....... 148

69 Effect of solvent on single-stranded scission of DNA..................... 150

70 Sensitivity of a strain, xthA, deficient in DNA repair...................... 156

71 Induction of the SOS response in E. coli GW 1040 by azure c and visible light. ............................................................ 157

72 Depletion of reduced glutathione in E. coli after exposure to dye, corrected for survival.......................................... 166

73 Survival of azure c treatment by strains bearing plasmids encoding different repair enzymes................................................. 168

74 Effect of azure c on survival on preinduced strains with and without the catalase plasmid........................................... 171

75 In vivo DNA damage by acridine orange........................................ 173

76 In vivo DNA damage by azure c is ameliorated by the OH. scavenger thiourea............................................................. 174

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