FIG 5.

SaeRS and SrrAB influence fermentative biofilm formation independently of one another. (A) Induction of fermentative biofilm formation is nearly absent in the ΔsrrAB saeS::Tn strain. The biofilm formation of the WT (JMB 1100) and the ΔsrrAB saeS::Tn (JMB 7068) strains following aerobic and fermentative growth is displayed. To allow assessment of induction levels, the data were normalized to the biofilm levels displayed by each strain under aerobic growth. (B and C) The biofilm formation phenotypes of the ΔsaeS::Tn and ΔsrrAB mutations are additive. The biofilm formation of the WT, ΔsrrAB (JMB 1467), saeS::Tn (JMB 7076), and ΔsrrAB saeS::Tn strains following fermentative growth is displayed. Data were normalized with respect to the WT (B) or with respect to the parental strain into which the ΔsrrAB mutation was introduced (i.e., the WT or saeS::Tn strain) (C). The data represent the average values for eight wells, and error bars represent standard deviations. Error bars are displayed for all data but on occasion may be too small to see. Statistical significance was calculated using a two-tailed Student's t test. *, P < 0.05.