title: Escherichia coli O157:H7 LPS O-side chains and pO157 are required for killing Caenorhabditis elegans.
abstract: As a model host, the nematode Caenorhabditis elegans has been used for studying unknown pathogen-host interactions and identifying novel virulence factors in bacterial pathogens. Among the bacterial pathogens that can induce death of C. elegans is enterohemorrhagic Escherichia coli (EHEC) O157:H7, a major serotype of EHEC that causes hemorrhagic colitis and hemolytic uremic syndrome in humans and animals. However, it is unknown which EHEC O157:H7 factors are required for nematode death. In this study, bacterial ability to kill C. elegans was tested for several EHEC O157:H7 wild-type and mutant strains missing one virulence-associated factor, including Shiga toxins, enterohemolysin, pO157 (a large virulence plasmid in EHEC O157:H7), Type 3 secretion system, LuxS, and lipopolysaccharide (LPS) O-side chains. Our results demonstrate that only mutants lacking either pO157 or LPS O-side chains cause full attenuation in killing C. elegans. The LPS O-side chain-defective ΔperA mutant strain was not able to colonize in the intestine even at 24h post-feeding with C. elegans, while the wild-type strain began to accumulate and colonize in the intestine as early as 3h post-feeding. A simple complementation of the mutant strain with the plasmid carrying the intact perA gene in trans completely restored the production of LPS O-side chains, as well as the ability to kill C. elegans. Our results show that pO157 and PerA are required for EHEC O157:H7 to kill C. elegans.
authors.affiliation: Department of Chemistry and Nano Sciences (BK21), Ewha Womans University, Seoul 120-750, Republic of Korea.
authors.forename: Min
authors.initials: M
authors.lastname: Youn
authors.forename: Kang-Mu
authors.initials: KM
authors.lastname: Lee
authors.forename: So Hyun
authors.initials: SH
authors.lastname: Kim
authors.forename: Jeesun
authors.initials: J
authors.lastname: Lim
authors.forename: Jang W
authors.initials: JW
authors.lastname: Yoon
authors.forename: Sungsu
authors.initials: S
authors.lastname: Park
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D017173:Caenorhabditis elegans / Q000382:microbiology*; D013437:Carbon-Sulfur Lyases / Q000235:genetics / Q000378:metabolism; D004195:Disease Models, Animal; D019453:Escherichia coli O157 / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D006460:Hemolysin Proteins / Q000378:metabolism; D007422:Intestines / Q000382:microbiology; D019081:O Antigens / Q000235:genetics / Q000378:metabolism*; D010957:Plasmids / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D013997:Time Factors; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D006460:Hemolysin Proteins; D019081:O Antigens; D012097:Repressor Proteins; D037521:Virulence Factors; C120886:bfpT protein, E coli; C066219:enterohemolysin; D013437:Carbon-Sulfur Lyases; C117753:LuxS protein, Bacteria
keywords: Caenorhabditis elegans; Escherichia coli O157:H7; Lipopolysaccharide; O-side chains