Quantitative estimation of UV light dose concomitant to irradiation with ionizing radiation

Петин, В.Г.; Морозов, И. И.; Kim, Jin Kyu; Semkina, M. A.

doi:10.1016/j.radphyschem.2010.08.006

Cited by 3 publications

(2 citation statements)

References 19 publications

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“…To overcome this limitation, new processes have been designed by combining several technologies applied at lower intensities, but with equivalent or even higher degrees of stability and safety. The interactions of UV light applied simultaneously with chemical agents (8,9,10) and with different energies, such as ionizing radiation (11) and heat (12)(13)(14), have been reported. Regarding the latter, there is an increased interest in the potential use of UV light combined with mild heat (UV-H treatments) for pasteurization of high-UV-absorptivity liquid foods (15), as this combination has been demonstrated to have a synergistic lethal effect on Escherichia coli (12) and Salmonella enterica subsp.…”

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confidence: 99%

Mechanism of the Synergistic Inactivation of Escherichia coli by UV-C Light at Mild Temperatures

Gayán

Mañas

Alvarez

et al. 2013

Appl Environ Microbiol

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UV light only penetrates liquid food surfaces to a very short depth, thereby limiting its industrial application in food pasteurization. One promising alternative is the combination of UV light with mild heat (UV-H), which has been demonstrated to produce a synergistic bactericidal effect. The aim of this article is to elucidate the mechanism of synergistic cellular inactivation resulting from the simultaneous application of UV light and heat. The lethality of UV-H treatments remained constant below ϳ45°C, while lethality increased exponentially as the temperature increased. The percentage of synergism reached a maximum (40.3%) at 55°C. Neither the flow regimen nor changes in the dose delivered by UV lamps contributed to the observed synergism. UV-H inactivation curves of the parental Escherichia coli strain obtained in a caffeic acid selective recovery medium followed a similar profile to those obtained with uvrA mutant cells in a nonselective medium. Thermal fluidification of membranes and synergistic lethal effects started around 40 to 45°C. Chemical membrane fluidification with benzyl alcohol decreased the UV resistance of the parental strain but not that of the uvrA mutant. These results suggest that the synergistic lethal effect of UV-H treatments is due to the inhibition of DNA excision repair resulting from the membrane fluidification caused by simultaneous heating. U V-C light is an emerging disinfection technology for water and, more recently, for liquid foods due to its multiple advantages (1, 2). UV-C (220 to 300 nm) has a germicidal effect for most types of microorganisms because it produces photochemical modifications of nucleic acids' pyrimidine bases. The major UVinduced DNA lesion is cyclobutane pyrimidine dimers (CPDs), while (6-4) photoproducts (6-4PPs) are also formed on about 25% of CPDs (3). These lesions prevent the proper replication and transcription of DNA, resulting in mutagenesis and, ultimately, cell death (4). The magnitude of the lethal effect depends on the radiation dose and on the cells' ability to repair damage.Microorganisms have adopted various enzymatic DNA repair pathways to restore DNA molecules from replication errors and the action of both endogenous and exogenous DNA-damaging agents. The DNA repair pathways involved in damage repair prior to replication include photorepair, base excision repair (BER), and nucleotide excision repair (NER) (3, 4). Under extensive DNA damage, repair mechanisms controlled by the SOS regulon, such as RecA-mediated excision repair (RAMER), translesion synthesis (TLS), and homologous recombination (HR) repair, are induced (4, 5). Overall, the lethality of UV light could be improved by impairing bacterial DNA repair mechanisms.The ability of UV light to be used for liquid food hygienization has been widely demonstrated (2, 6). In fact, UV-based technologies have been approved as alternative treatments to thermal pasteurization of fresh juice products (7). However, the implementation of UV processing in the food industry is still limited due to ...

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confidence: 99%

Mechanism of the Synergistic Inactivation of Escherichia coli by UV-C Light at Mild Temperatures

Gayán

Mañas

Alvarez

et al. 2013

Appl Environ Microbiol

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“…We can, therefore, conclude in line with Ewing (1987) that the protective eff ect of the studied scavengers must be a more complex process than the simple scavenging of • OH radicals. Th e process may become more complicated, among others, by the fact that irradiation of microbial culture with high energy ionizing radiation is always accompanied by the concomitant UV irradiation (Petin et al 2011). Besides, the measured eff ect of scavengers does not distinguish between the direct and indirect action of ionizing radiation.…”

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confidence: 99%

Influence of various scavengers of •OH radicals on the radiation sensitivity of yeast and bacteria

Múčka

Bláha

Čuba

et al. 2013

International Journal of Radiation Biology

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The main results of the paper were: The surviving fraction increased approximately linearly within the measured interval with increasing concentration of the scavenger. The same dependences were found for the protecting effect depending on the scavenging efficiency. The slopes of these dependences (k) were found to be characteristic for each scavenger. The k value determined the degree in which the scavenging of •OH radicals participated in the protection of living cells. The protective effects of scavengers at the same scavenging efficiency were different and unique for each scavenger. No simple relation was found between the efficiency of scavenger k and the rate constant kOH of the reactions between scavengers and •OH radicals. Our results suggest that the studied scavengers effectively protected yeast and bacteria against ionizing radiation. Although the scavenging of •OH radicals seems to be important for protection of living cells, it is clearly not the only process on which the protection is based.

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Ethanol as a Modifier of Radiation Sensitivity of Living Cells Against Uv-C Radiation

Neužilová

Ondrák

Čuba

et al. 2019

Radiation Protection Dosimetry

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Quantitative estimation of UV light dose concomitant to irradiation with ionizing radiation

Cited by 3 publications

References 19 publications

Mechanism of the Synergistic Inactivation of Escherichia coli by UV-C Light at Mild Temperatures

Mechanism of the Synergistic Inactivation of Escherichia coli by UV-C Light at Mild Temperatures

Influence of various scavengers of •OH radicals on the radiation sensitivity of yeast and bacteria

Ethanol as a Modifier of Radiation Sensitivity of Living Cells Against Uv-C Radiation

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