Fig. 3.
DvhD rescues the biofilm phenotype of Pf0-1. (A) The gene encoding HA-tagged DvhD gene from D. vulgaris Hildenborough was inserted at the Tn7 att site under the control of IPTG-inducible Ptac promoter in the Pf0-1 ΔlapGΔlapDdvhA-hlx-swap strain. The lacI gene was also introduced at the att site to repress dvhD gene expression in the absence of IPTG. The diagram depicts the regulatory control of dvhD expression. (B) Whole-cell western blot for HA-tagged proteins shows minimal DvhD without IPTG and robust DvhD level in the presence of IPTG. (C) Biofilm formed by the Pf0-1 attTn7::lacI-PtacdvhD-HA ΔlapGΔlapDdvhA-hlx-swap strain in K10T medium at 24 h. Quantification was performed on the strain containing no vector, empty vector and plasmid expressing full-length DvhG. Arabinose at 0.2% and IPTG at 0.01% were used to induce dvhG expression from the plasmid and dvhD expression from the genome, respectively. (D and E) Quantification of DvhA-hlx-swap on the cell surface (D) and the culture supernatant (E) using dot blots in the presence or absence of IPTG. The analyzed strains carried either an empty vector or a plasmid expressing full-length DvhG, all under inducing conditions with 0.2% arabinose. Statistical analysis was performed using one-way ANOVA corrected for multiple comparisons (ns, P > 0.05; *P ≤ 0.05; **P ≤ 0.01; ***P ≤ 0.001; ****P ≤ 0.0001).