Effect of energy limitation on microbial epigenetic modifications
Date
2021
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Publisher
University of Delaware
Abstract
Epigenetic modifications are often induced in eukaryotic organisms in a response to stress. These modifications can alter gene expression by methylating the genome which can turn genes on or off. These modifications have not been as widely investigated in prokaryotic organisms. Microbial populations in the deep sea are able to sustain standing populations despite no new known energy inputs. While studies have attempted to investigate their capability of surviving in these low nutrient environments it is often attempted by inducing nutrient limited stress instead of energy limited stress. Energy limited stress would keep the organism metabolically active while nutrient limited stress would reduce an essential nutrient required for biomass. Here we induce energy limited stress to two organisms, Pseudomonas aeruginosa and Methanosarcina mazei and sequenced their genomes using long-read sequencing that includes kinetic information to detect modified bases. Pseudomonas aeruginosa PAO1 was energy starved using various amino acids as the sole carbon and energy source. Indication of stress in PAO1 include a slowed growth to the production of a secondary metabolite that is often present in virulent PAO1. M. mazei was energy starved by reducing acetate, its preferred electron source based on its methanogenesis pathway. DNA analysis of PAO1 revealed a hypomethylated genome during the stationary phase of the starved condition with the majority of the modifications occurring in the rRNA region of the genome. Further analysis reveals a difference in OMPK of the starved condition to the normal condition in which genes that were hypermethylated were associated with proton transport and protein metabolic processes.
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Keywords
Energy limitation, Microbial, Epigenetic