Escherichia coli heat-shock proteins IbpA and IbpB affect biofilm formation by influencing the level of extracellular indole

• Published in: Microbiology (Society for General Microbiology) 2010-01, Vol.156 (1), p.148-157
• Main Authors: Kuczynska-Wisnik, Dorota, Matuszewska, Ewelina, Laskowska, Ewa
• Format: Article
• Language: English
• Subjects: Bacteriology; Biofilms - growth & development; Biological and medical sciences; Escherichia coli - genetics; Escherichia coli - growth & development; Escherichia coli - metabolism; Escherichia coli Proteins - genetics; Escherichia coli Proteins - metabolism; Fundamental and applied biological sciences. Psychology; Heat-Shock Proteins - genetics; Heat-Shock Proteins - metabolism; Indoles - metabolism; Microbiology; Miscellaneous; Operon; Oxidative Stress; Tryptophanase - metabolism
• ISSN: 1350-0872; 1465-2080
• DOI: 10.1099/mic.0.032334-0

Department of Biochemistry, Faculty of Biology, University of Gda sk, K adki 24, 80-952 Gda sk, Poland The development of Escherichia coli biofilm requires the differential expression of various genes implicated in cell signalling, stress responses, motility and the synthesis of structures responsible for cell attachment. The ibpAB operon is among the stress-response genes most induced during growth of the E. coli biofilm. In this study we demonstrated, to our knowledge for the first time, that the lack of IbpAB proteins in E. coli cells inhibited the formation of biofilm at the air–liquid interface, although it allowed normal planktonic growth. We showed that ibpAB mutant cells experienced endogenous oxidative stress, which might result from a decreased catalase activity. The endogenous oxidative stress in ibpAB cells led to increased expression of tryptophanase, an enzyme which catalyses the synthesis of indole. We demonstrated that the formation of biofilm by the ibpAB mutant was delayed due to the increase in the extracellular concentration of indole, which is known to play the role of a signal molecule, inhibiting biofilm growth. Correspondence Ewa Laskowska lasko{at}biotech.ug.gda.pl Abbreviations: DNP, 2,4-dinitrophenol; DNPH, 2,4-dinitrophenylhydrazine; H 2 DCFDA, 2',7'-dichlorofluorescein diacetate; PVC, polyvinyl chloride; SOD, superoxide dismutase