Studies on the Irradiation of Microorganisms in Relation to Food Preservation: Ii. Irradiation Resistant Mutants

Erdman, I. E.; Thatcher, F. S.; MacQueen, K.F.

doi:10.1139/m61-027

Cited by 61 publications

(25 citation statements)

References 9 publications

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“…In other bacteria, one or more doses of radiation can cause an increase in radiation resistance (132,358,481), an increase in antibiotic resistance (498), morphological changes (173,358), biochemical changes (173), and decreased pathogenicity (180,498). Irradiated or chemically treated D. radiodurans cells usually give rise to colonies identical to those of unirradiated bacteria, although some colonies are smaller, pigmentless, and rough with irregular edges (161,434).…”

Section: Ionizing Radiation Resistance Of D Radioduransmentioning

confidence: 99%

Oxidative Stress Resistance inDeinococcus radiodurans

Slade

Radman

2011

Microbiol Mol Biol Rev

660

639

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SUMMARY Deinococcus radiodurans is a robust bacterium best known for its capacity to repair massive DNA damage efficiently and accurately. It is extremely resistant to many DNA-damaging agents, including ionizing radiation and UV radiation (100 to 295 nm), desiccation, and mitomycin C, which induce oxidative damage not only to DNA but also to all cellular macromolecules via the production of reactive oxygen species. The extreme resilience of D. radiodurans to oxidative stress is imparted synergistically by an efficient protection of proteins against oxidative stress and an efficient DNA repair mechanism, enhanced by functional redundancies in both systems. D. radiodurans assets for the prevention of and recovery from oxidative stress are extensively reviewed here. Radiation- and desiccation-resistant bacteria such as D. radiodurans have substantially lower protein oxidation levels than do sensitive bacteria but have similar yields of DNA double-strand breaks. These findings challenge the concept of DNA as the primary target of radiation toxicity while advancing protein damage, and the protection of proteins against oxidative damage, as a new paradigm of radiation toxicity and survival. The protection of DNA repair and other proteins against oxidative damage is imparted by enzymatic and nonenzymatic antioxidant defense systems dominated by divalent manganese complexes. Given that oxidative stress caused by the accumulation of reactive oxygen species is associated with aging and cancer, a comprehensive outlook on D. radiodurans strategies of combating oxidative stress may open new avenues for antiaging and anticancer treatments. The study of the antioxidation protection in D. radiodurans is therefore of considerable potential interest for medicine and public health.

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Section: Ionizing Radiation Resistance Of D Radioduransmentioning

confidence: 99%

Oxidative Stress Resistance inDeinococcus radiodurans

Slade

Radman

2011

Microbiol Mol Biol Rev

660

639

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“…In the 6 decades since the Witkin report, addi-tional investigators have repeated this result, demonstrating that iterative cycles of high-dose exposure to a DNA damaging agent can heritably enhance a culture's ability to tolerate that DNA damaging agent. Increases in IR resistance have been reported for E. coli (17), Salmonella enterica serovar Typhimurium (14), and Bacillus pumulis (44), organisms that are otherwise considered radiosensitive. Davies and Sinskey (14) showed that for S. enterica serovar Typhimurium LT2, the number of cycles of exposure and recovery correlates with the level of radioresistance achieved.…”

mentioning

confidence: 99%

Directed Evolution of Ionizing Radiation Resistance in Escherichia coli

et al. 2009

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We have generated extreme ionizing radiation resistance in a relatively sensitive bacterial species, Escherichia coli, by directed evolution. Four populations of Escherichia coli K-12 were derived independently from strain MG1655, with each specifically adapted to survive exposure to high doses of ionizing radiation. D 37 values for strains isolated from two of the populations approached that exhibited by Deinococcus radiodurans. Complete genomic sequencing was carried out on nine purified strains derived from these populations. Clear mutational patterns were observed that both pointed to key underlying mechanisms and guided further characterization of the strains. In these evolved populations, passive genomic protection is not in evidence. Instead, enhanced recombinational DNA repair makes a prominent but probably not exclusive contribution to genome reconstitution. Multiple genes, multiple alleles of some genes, multiple mechanisms, and multiple evolutionary pathways all play a role in the evolutionary acquisition of extreme radiation resistance. Several mutations in the recA gene and a deletion of the e14 prophage both demonstrably contribute to and partially explain the new phenotype. Mutations in additional components of the bacterial recombinational repair system and the replication restart primosome are also prominent, as are mutations in genes involved in cell division, protein turnover, and glutamate transport. At least some evolutionary pathways to extreme radiation resistance are constrained by the temporally ordered appearance of specific alleles.

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“…This is an important subject. Many very able microbiologists have been concerned and have researched it for many years (Among others: Erdman et al 1961;Thatcher 1963;Christensen and Kjems 1965;Licciardello et al 1969;Epps and Idziak 1970;Previtte et al 1970;Cliver 1977;Maxcy 1977).…”

Section: The Microbial Mutantsmentioning

confidence: 99%