, 2001a, b). Mutator bacteria do not constitute a large fraction of natural bacterial isolates because they accumulate adaptive and neutral mutations in the current environment that can be deleterious in a secondary environment, thus imparting long-term disadvantage (Giraud et al., 2001a, b). The sediment in Lake Oneida from which S. oneidensis MR-1 was isolated is a highly eutrophic environment, prone to frequent wind mixing events and the establishment of temporary redox gradients in the sediments and water (Dean et al., 1981; Mitchell et al., 1996; Ausubel, 2008; Domack, 2008). These conditions result in the creation of temporary microenvironments in sediments (Greeson,
1971; Ausubel, 2008; Domack, 2008). Such an environment would select for mutator bacteria phylotypes capable of survival through the development of environmental adaptations including the ability to use glucose as the only carbon source with high frequency. The ability www.selleckchem.com/products/jq1.html of S. oneidensis MR-1 to use glucose HIF inhibitor as a sole carbon source via a mutator population or a GASP mutation (although these are not mutually exclusive) suggests interesting ecological implications. Members of the Shewanella genus have great flexibility in terms of growth strategy and metabolisms (Tang et al., 2009),
allowing them to proliferate in diverse and changing environments. The ability to maintain a mutator population within Shewanella species and/or gain GASP mutations indicates that the genus and specifically S. oneidensis MR-1 have other understudied mechanisms to assist them with establishing populations in highly variable environments. We thank Preston A. Fulmer for laboratory assistance. We also thank Russell Kirk Pirlo, Lisa A. Fitzgerald, Justin C. Biffinger, and anonymous reviewers for helpful comments. This work was funded by the Office of Naval Research through NRL Program Element Number 62123N and NRL Program Element Number 17-DMAG (Alvespimycin) HCl 61153N. This
work was carried out while E.C.H. held a National Research Council Post-Doctoral Associateship. “
“The hetero-oligomeric FlhD/FlhC complex is a global regulator of transcription in Escherichia coli. FlhD alone, independent of FlhC, has also been reported to control when E. coli cells stop dividing and enter the stationary phase. This work is frequently cited as evidence that FlhD regulates cell division; however, our data indicate that this is not the case. The results presented here show that the previously observed phenotype is not due to the flhD locus, but is instead due to differences in the thyA alleles present in the flhD+ and flhD− strains used in the original studies. We find that when the strains being compared have the same thyA allele (wild type or mutant), flhD mutations have no effect on growth. The hetero-oligomeric FlhD/FlhC complex is a global regulator of gene expression in Escherichia coli.