Repair processes in germinating seeds: Caffeine enhancement of damage induced by gamma-radiation and alkylating chemicals

Ahnström, Gunnar

doi:10.1016/s0027-5107(74)80040-0

Cited by 36 publications

(5 citation statements)

References 14 publications

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“…Various studies on metabolizing systems also suggest that potentiation of the radiation-induced damage occurs only when caffeine is added within 4 to 5 hours of irradiation (Ahnstrom and Natarajan 1971, Ahnstrom 1974, Balachandran and Kesavan 1974 . Hence, it is possible to propose that whatever mechanisms of chemical radioprotection and sensitization operate in the dry systems also seem to occur in the wet systems .…”

Section: Resultsmentioning

confidence: 99%

“…On the basis of a radical-scavenging hypothesis, this might imply that cysteine eliminates only the radiation-induced oxygen-sensitive sites, although both sensitive and insensitive sites are basically free radicals . Kesavan, Trasi and Ahmad (1973) also observed that caffeine, a well-known radiosensitizer said to act via inhibition of biochemical repair mechanisms (Harm 1967, Bendigkeit and Hanawalt 1968, Cleaver and Thomas 1969, Domon and Rauth 1969, Yamamoto and Yamaguchi 1969, Fabre 1972, Gaudin, Gregg and Yielding 1972, Rommelaere and Errera 1972, Witte and Bohme 1972, Ahnstrom 1974, also affords partial protection against post-irradiation oxic damage (class III of Powers (1961) or A,, of Dodd and Ebert (1970)) . However, unlike cysteine, caffeine potentiates the oxygen-independent component of damage (Kesavan 1973, Kesavan and Ahmad 1974 .…”

Section: Introductionmentioning

confidence: 99%

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Dependence of Chemical Radioprotection on the Stability of Radiation-induced Oxygen-sensitive Sites

Kesavan

Afzal

1975

International Journal of Radiation Biology and Related Studies

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Dependence of Chemical Radioprotection on the Stability of Radiation-induced Oxygen-sensitive Sites

Kesavan

Afzal

1975

International Journal of Radiation Biology and Related Studies

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“…In barley seeds, the radioprotective action of caf against the oxic pathway might depend on the yield and stability of the radiation-induced, 2 -sensitive sites Afzal 1975, Nadkarni and. These observations (concentration-dependence and differential modification of the oxic and anoxic components of radiation damage) cannot be explained by any of the existing biochemical interpretations which all, in one way or another, revolve around inhibition of repair of DNA by caf to cause potentiation (Ts'o and Lu 1964, Bendigkeit and Hanawalt 1968, Cleaver and Thomas 1969, Domon and Rauth 1969, Yamamoto and Yamaguchi 1969, Mitznegg et al 1971, Fabre 1972, Zuk and Swietlifiska 1973, Ahnstrom 1974). The demonstration that at a given concentration and gaseous circumstance caf exerts varied and indeed opposite effects on the oxic and anoxic components implicates a physicochemical mode of action in both the eukaryotic seeds and prokaryotic spores.…”

Section: Discussionmentioning

confidence: 97%

Differential Modification of Oxic and Anoxic Components of Radiation Damage inBacillus MegateriumSpores by Caffeine

Kesavan¹,

Powers²

1985

International Journal of Radiation Biology and Related Studies

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Studies were carried out on the effect of caffeine on the X-irradiation sensitivity of B. megaterium spores with the following results: Caffeine exerts a concentration-dependent modifying action on oxygen-dependent components of X-ray-induced damage in B. megaterium spore suspensions causing an 'over-O2 effect' at about 1 X 10(-4) mol dm-3, and as the concentration is increased to 1 X 10(-3) mol dm-3 or above, a small but consistent protection is seen. In the absence of O2, at a wide range of concentrations (8.5 X 10(-5) to 1 X 10(-1) mol dm-3), caffeine enhances the inactivation constant, k, from 1.17 to about 1.50 kGy-1. Both ethanol and t-butanol (5 X 10(-2) mol dm-3) remove the 'over O2-effect' produced by 1.10(-4) mol dm-3 caffeine in O2; such an effect, however, is not accompanied by reduction in the H2O2 concentrations in the spore suspensions. Ethanol prevents caffeine-induced anoxic sensitization, as well as H2O2 buildup. t-BuOH has no influence on either the low dose part of the log fraction survival curve or on the H2O2 yield in the spore suspensions. Caffeine reacts with radiation-induced eaq and .OH with rate constants of 1.5 X 10(10) and 6.9 X 10(9) dm3 mol-1s-1, respectively.

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“…Caffeine is known to increase the amount of mitotic chromosomal damage in plant cells with or without EMS treatment or -irradiation (Ahnströ m, 1974;Swietlinska and Zuk, 1974;Timson, 1997). However, in these studies, the caffeine-induced increment in DNA damage was recorded as broken chromatids in chromosomes that had already reached mitosis.…”

Section: Introductionmentioning

confidence: 99%

Effect of caffeine on in vivo processing of alkylated bases in proliferating plant cells

Pincheira

López-Sáez

Carrera

et al. 2003

Cell Biology International

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DNA damage was induced by either 2 mM ethylmethanesulfonate or 1 Gy of gamma-irradiation in Allium cepa L. root meristems. The percentage of DNA that migrated towards the anode during microelectrophoresis after alkali denaturation (pH approximately 13.5) of the isolated nuclei (comet assay) reflects the amount of single strand breaks present in them. There was some DNA migration (12.8+/-2.4%) in untreated roots. This percentage doubled at the end of 1.5 h treatment with the mono-functional alkylating agent 2 mM ethylmethanesulfonate, and trebled after a single exposure to 1 Gy of gamma-rays. A proportion of the DNA migration caused by these two treatments was reversed (repaired) by a 2 h long period of in vivo recovery. However, when 5 mM caffeine was applied after removal of the alkylating agent, the amount of DNA migrating to the comet tail over the same 2 h period was almost double that at the onset of recovery. In both control and irradiated nuclei, caffeine also increased the initial level of DNA migration in the comet assay, but to a lesser extent. These results indicate that caffeine increases the DNA damage that accumulates during the processing of alkylated bases and, to a lesser extent, of the DNA bases damaged by gamma-irradiation. Thus, the potentiation effect of caffeine on induced chromosomal damage may not just be due to caffeine-induced cancellation of the G2 checkpoint, but also to a direct effect this methylxantine has on the processing of DNA damage.

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Repair processes in germinating seeds: Caffeine enhancement of damage induced by gamma-radiation and alkylating chemicals

Cited by 36 publications

References 14 publications

Dependence of Chemical Radioprotection on the Stability of Radiation-induced Oxygen-sensitive Sites

Dependence of Chemical Radioprotection on the Stability of Radiation-induced Oxygen-sensitive Sites

Differential Modification of Oxic and Anoxic Components of Radiation Damage inBacillus MegateriumSpores by Caffeine

Effect of caffeine on in vivo processing of alkylated bases in proliferating plant cells

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