Mapping stress-induced changes in autoinducer AI-2 production in chemostat-cultivated Escherichia coli K-12

Citation
Mp. Delisa et al., Mapping stress-induced changes in autoinducer AI-2 production in chemostat-cultivated Escherichia coli K-12, J BACT, 183(9), 2001, pp. 2918-2928
Citations number
60
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Microbiology
Journal title
JOURNAL OF BACTERIOLOGY
ISSN journal
0021-9193 → ACNP
Volume
183
Issue
9
Year of publication
2001
Pages
2918 - 2928
Database
ISI
SICI code
0021-9193(200105)183:9<2918:MSCIAA>2.0.ZU;2-Q
Abstract
Numerous gram-negative bacteria employ a cell-to-cell signaling mechanism, termed quorum sensing, for controlling gene expression in response to popul ation density. Recently, this phenomenon has been discovered in Escherichia coli, and while pathogenic E. coti utilize quorum sensing to regulate path ogenesis (i.e., expression of virulence genes), the role of quorum sensing in nonpathogenic E. coli is less clear, and in particular, there is no info rmation regarding the role of quorum sensing during the overexpression of r ecombinant proteins. The production of autoinducer AI-2, a signaling molecu le employed by E. coli for intercellular communication, was studied in E. c oli W3110 chemostat cultures using a Vibrio harveyi AI-2 reporter assay (M. G, Surrette and B, L. Bassler, Proc. Natl, Acad. Sci. USA 95:7046-7050, 19 98). Chemostat cultures enabled a study of AI-2 regulation through steady-s tate and transient responses to a variety of environmental stimuli. Results demonstrated that AI-2 levels increased with the steady-state culture grow th rate. In addition, AI-2 increased following pulsed addition of glucose, Fe(III), NaCl, and dithiothreitol and decreased following aerobiosis, amino acid starvation, and isopropyl-beta -D-thiogalactopyranaside-induced expre ssion of human interleukin-2 (hIL-2), In general, the AI-2 responses to sev eral perturbations were indicative of a shift in metabolic activity or stat e of the cells induced by the individual stress. Because of our interest in the expression of heterologous proteins in E. coli, the transcription of f our quorum-regulated genes and 20 stress genes was mapped during the transi ent response to induced expression of hIL-2. Significant regulatory overlap was revealed among several stress and starvation genes and known quorum-se nsing genes.