Dataset Information

Characterization of the SOS response of Pseudomonas fluorescens strain DC454 using whole genome transcript analysis

ABSTRACT: DNA microarray technology was used to survey changes in gene expression in P. fluorescens after mitomycin C (MMC) treatment. As expected, genes associated with the SOS response were upregulated. These include genes coding the recombination involved protein RecA, DNA repair protein RecN, excinuclease ABC subunit A UvrA, and the LexA repressor protein. The expression profile was similar to that which had been shown for E. coli after MMC treatment. Interestingly, expression of 33 bacteriophage-like genes was upregulated two hours after MMC treatment. Those genes are clustered in the chromosome. This result suggests that MMC may induce a prophage resident in the P. fluorescens genome. However, no phage particles were detected in a preparation of P. fluorescens strain DC454 that had been treated with MMC using transmission electron microscopy, and the same preparation failed to produce phage plaques on lawns of any of 10 different Pseudomonas strains tested, suggesting that the 33 bacteriophage-like gene cluster represents a defective prophage. Keywords: time course, stress response

ORGANISM(S): Pseudomonas fluorescens

PROVIDER: GSE5653 | GEO | 2006/12/11

SECONDARY ACCESSION(S): PRJNA96859

REPOSITORIES: GEO

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Project description:Optimality of the spontaneous prophage induction rate. Cortes MG1, Krog J2, Balázsi G3. 1 Department of Applied Mathematics and Statistics, Stony Brook University, Stony Brook, NY 11794, USA. 2 The Louis and Beatrice Laufer Center for Physical and Quantitative Biology, Stony Brook University, Stony Brook, NY 11794, USA. 3 Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794, USA. Electronic address: gabor.balazsi@stonybrook.edu. Abstract Lysogens are bacterial cells that have survived after genomically incorporating the DNA of temperate bacteriophages infecting them. If an infection results in lysogeny, the lysogen continues to grow and divide normally, seemingly unaffected by the integrated viral genome known as a prophage. However, the prophage can still have an impact on the host's phenotype and overall fitness in certain environments. Additionally, the prophage within the lysogen can activate the lytic pathway via spontaneous prophage induction (SPI), killing the lysogen and releasing new progeny phages. These new phages can then lyse or lysogenize other susceptible nonlysogens, thereby impacting the competition between lysogens and nonlysogens. In a scenario with differing growth rates, it is not clear whether SPI would be beneficial or detrimental to the lysogens since it kills the host cell but also attacks nonlysogenic competitors, either lysing or lysogenizing them. Here we study the evolutionary dynamics of a mixture of lysogens and nonlysogens and derive general conditions on SPI rates for lysogens to displace nonlysogens. We show that there exists an optimal SPI rate for bacteriophage λ and explain why it is so low. We also investigate the impact of stochasticity and conclude that even at low cell numbers SPI can still provide an advantage to the lysogens. These results corroborate recent experimental studies showing that lower SPI rates are advantageous for phage-phage competition, and establish theoretical bounds on the SPI rate in terms of ecological and environmental variables associated with lysogens having a competitive advantage over their nonlysogenic counterparts. Copyright © 2019 The Author(s). Published by Elsevier Ltd.. All rights reserved.

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