A previously uncharacterized gene, yjfO (bsmA), influences Escherichia coli biofilm formation and stress response.
Bacteria growing as surface-adherent biofilms are better able to withstand chemical and physical stresses than their unattached, planktonic counterparts. Using transcriptional profiling and quantitative PCR, we observed a previously uncharacterized gene, yjfO to be upregulated during Escherichia coli MG1655 biofilm growth in a chemostat on serine-limited defined medium. A yjfO mutant, developed through targeted-insertion mutagenesis, and a yjfO-complemented strain, were obtained for further characterization. While bacterial surface colonization levels (c.f.u. cm(-2)) were similar in all three strains, the mutant strain exhibited reduced microcolony formation when observed in flow cells, and greatly enhanced flagellar motility on soft (0.3 %) agar. Complementation of yjfO restored microcolony formation and flagellar motility to wild-type levels. Cell surface hydrophobicity and twitching motility were unaffected by the presence or absence of yjfO. In contrast to the parent strain, biofilms from the mutant strain were less able to resist acid and peroxide stresses. yjfO had no significant effect on E. coli biofilm susceptibility to alkali or heat stress. Planktonic cultures from all three strains showed similar responses to these stresses. Regardless of the presence of yjfO, planktonic E. coli withstood alkali stress better than biofilm populations. Complementation of yjfO restored viability following exposure to peroxide stress, but did not restore acid resistance. Based on its influence on biofilm maturation and stress response, and effects on motility, we propose renaming the uncharacterized gene, yjfO, as bsmA (biofilm stress and motility).
Weber
Mary M
MM
Department of Biology, Texas State University-San Marcos, 601 University Drive, San Marcos, TX 78666, USA.
French
Christa L
CL
Department of Biology, Texas State University-San Marcos, 601 University Drive, San Marcos, TX 78666, USA.
Barnes
Mary B
MB
Tulane National Primate Research Center, 18703 Three Rivers Road, Covington, LA 70433-8915, USA.
Siegele
Deborah A
DA
Department of Biology, Texas A&M University, College Station, TX 77843-3258, USA.
McLean
Robert J C
RJC
Department of Biology, Texas State University-San Marcos, 601 University Drive, San Marcos, TX 78666, USA.
D018441:Biofilms / Q000254:growth & development*; D004926:Escherichia coli / Q000235:genetics* / Q000254:growth & development; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D005816:Genetic Complementation Test; D006863:Hydrogen-Ion Concentration; D016254:Mutagenesis, Insertional; D009154:Mutation; D018384:Oxidative Stress; D012329:RNA, Bacterial / Q000235:genetics
D029968:Escherichia coli Proteins; D012329:RNA, Bacterial