PMID:23046700

Citation	Han, X, Bai, H, Liu, L, Dong, H, Liu, R, Song, J, Ding, C, Qi, K, Liu, H and Yu, S (2013) The luxS gene functions in the pathogenesis of avian pathogenic Escherichia coli. Microb. Pathog. 55:21-7
Abstract	Avian pathogenic Escherichia coli (APEC) causes avian colibacillosis, the most significant infectious bacterial disease of poultry worldwide. LuxS, the product of the luxS gene, mediates the quorum sensing (QS) mechanism. This involves the production of autoinducer-2 (AI-2), which regulates important physiological traits and a variety of adaptive processes in different bacteria. In this study, a luxS gene deleted APEC mutant strain, ΔDE17, was constructed using strain DE17. Analysis of bioluminescence indicated that deletion of the luxS gene abolished the production of the QS signal AI-2 in the bacteria. Further studies showed that deletion of the luxS gene in DE17 reduced the bacterial virulence by 31.5-fold in ducklings, based on the measurement of the 50% lethal dose. The mutant strain reduced significantly the abilities of adherence and invasion, by 50.0% and 40.7% respectively, compared with the wild strain DE17. The mutant strain also showed reduced survival in vivo: the bacterial loads of the mutant strain in infected liver, spleen and blood were 46.4-fold, 5.2-fold, and 3.7-fold reduced, respectively, compared with the wild-type strain DE17. Real-time polymerase chain reaction (PCR) demonstrated further that the mRNA levels of the virulence-related genes iucD, fyuA, vat, ompA, iss, fimC and tsh were significantly decreased in the mutant strain ΔDE17, when compared with DE17 (p < 0.05). In addition, the deletion of the luxS gene reduced the motility of the bacterium. This study suggests that the luxS gene functions in the pathogenesis of diseases caused by avian pathogenic E. coli.
Links	PubMed Online version:10.1016/j.micpath.2012.09.008
Keywords	Animals; Bacterial Proteins/genetics; Bacterial Proteins/metabolism; Carbon-Sulfur Lyases/genetics; Carbon-Sulfur Lyases/metabolism; Ducks; Escherichia coli/genetics; Escherichia coli/pathogenicity; Escherichia coli/physiology; Escherichia coli Infections/microbiology; Escherichia coli Infections/veterinary; Female; Gene Expression Regulation, Bacterial; Male; Poultry Diseases/microbiology; Quorum Sensing; Sequence Deletion; Virulence
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
ECOK1:LUXS	involved_in	GO:0009372: quorum sensing	ECO:0000315: mutant phenotype evidence used in manual assertion		P		Seeded From UniProt	complete
ECOK1:LUXS		GO:0009372: quorum sensing	ECO:0000315:		P		Figure 3 shows that the mutant strain without the LuxS gene produces much less AI-2. AI-2 is a universal signaling molecule produced by many different types of bacterial to mediate quorum sensing.	complete CACAO 10055
ECOK1:LUXS		GO:2000145: regulation of cell motility	ECO:0000315:		P		Figure 4 shows that the mutant strain without the LuxS gene exhibits much less motility than the wild-type strain.	complete CACAO 10063
ECOK1:LUXS	involved_in	GO:2000145: regulation of cell motility	ECO:0000315: mutant phenotype evidence used in manual assertion		P		Seeded From UniProt	complete

References

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