Experimental Evolution of Extreme Resistance to Ionizing Radiation in Escherichia coli after 50 Cycles of Selection
Autor: | Steven T. Bruckbauer, Matthew J. Blow, Michael M. Cox, Brian Bushnell, Joseph D. Trimarco, Wendy Schackwitz, Katherine A. Senn, Elizabeth A. Wood, Anna Lipzen, Christa Pennacchio, Joel Martin, Wesley S. Culberson |
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Přispěvatelé: | Silhavy, Thomas J |
Rok vydání: | 2019 |
Předmět: |
Ionizing
DNA Mutational Analysis 2.2 Factors relating to physical environment Radiation Tolerance Medical and Health Sciences chemistry.chemical_compound 0302 clinical medicine Radiation Ionizing 2.2 Factors relating to the physical environment Deinococcus Aetiology Genetics 0303 health sciences Experimental evolution Radiation biology RecD High-Throughput Nucleotide Sequencing DNA-Directed RNA Polymerases Biological Sciences Biological Evolution 030220 oncology & carcinogenesis Infection ionizing radiation Research Article DNA repair Microbiology Deep sequencing 03 medical and health sciences Genetic evolution Escherichia coli Selection Genetic Selection Molecular Biology Gene RecN 030304 developmental biology RpoB RpoC Agricultural and Veterinary Sciences Human Genome Deinococcus radiodurans biology.organism_classification rpoB DNA Repair Enzymes chemistry Mutation Antimicrobial Resistance DNA |
Zdroj: | Bruckbauer, Steven T; Trimarco, Joseph D; Martin, Joel; Bushnell, Brian; Senn, Katherine A; Schackwitz, Wendy; et al.(2019). Experimental Evolution of Extreme Resistance to Ionizing Radiation in Escherichia coli after 50 Cycles of Selection.. Journal of bacteriology, 201(8). doi: 10.1128/jb.00784-18. Lawrence Berkeley National Laboratory: Retrieved from: http://www.escholarship.org/uc/item/0mt359p5 Journal of bacteriology, vol 201, iss 8 |
ISSN: | 1098-5530 0021-9193 |
Popis: | In previous work (D. R. Harris et al., J Bacteriol 191:5240–5252, 2009, https://doi.org/10.1128/JB.00502-09; B. T. Byrne et al., Elife 3:e01322, 2014, https://doi.org/10.7554/eLife.01322), we demonstrated that Escherichia coli could acquire substantial levels of resistance to ionizing radiation (IR) via directed evolution. Major phenotypic contributions involved adaptation of organic systems for DNA repair. We have now undertaken an extended effort to generate E. coli populations that are as resistant to IR as Deinococcus radiodurans. After an initial 50 cycles of selection using high-energy electron beam IR, four replicate populations exhibit major increases in IR resistance but have not yet reached IR resistance equivalent to D. radiodurans. Regular deep sequencing reveals complex evolutionary patterns with abundant clonal interference. Prominent IR resistance mechanisms involve novel adaptations to DNA repair systems and alterations in RNA polymerase. Adaptation is highly specialized to resist IR exposure, since isolates from the evolved populations exhibit highly variable patterns of resistance to other forms of DNA damage. Sequenced isolates from the populations possess between 184 and 280 mutations. IR resistance in one isolate, IR9-50-1, is derived largely from four novel mutations affecting DNA and RNA metabolism: RecD A90E, RecN K429Q, and RpoB S72N/RpoC K1172I. Additional mechanisms of IR resistance are evident. IMPORTANCE Some bacterial species exhibit astonishing resistance to ionizing radiation, with Deinococcus radiodurans being the archetype. As natural IR sources rarely exceed mGy levels, the capacity of Deinococcus to survive 5,000 Gy has been attributed to desiccation resistance. To understand the molecular basis of true extreme IR resistance, we are using experimental evolution to generate strains of Escherichia coli with IR resistance levels comparable to Deinococcus. Experimental evolution has previously generated moderate radioresistance for multiple bacterial species. However, these efforts could not take advantage of modern genomic sequencing technologies. In this report, we examine four replicate bacterial populations after 50 selection cycles. Genomic sequencing allows us to follow the genesis of mutations in populations throughout selection. Novel mutations affecting genes encoding DNA repair proteins and RNA polymerase enhance radioresistance. However, more contributors are apparent. |
Databáze: | OpenAIRE |
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