title: Heat-killed Lactobacillus spp. cells enhance survivals of Caenorhabditis elegans against Salmonella and Yersinia infections.
abstract: This study examined the effect of feeding heat-killed Lactobacillus cells on the survival of Caenorhabditis elegans nematodes after Salmonella Typhimurium and Yersinia enterocolitica infection. The feeding of heat-killed Lactobacillus plantarum 133 (LP133) and Lactobacillus fermentum 21 (LP21) cells to nematodes was shown to significantly increase the survival rate as well as stimulate the expression of pmk-1 gene that key factor for C. elegans immunity upon infection compared with control nematodes that were only fed Escherichia coli OP50 (OP50) cells. These results suggest that heat-killed LP133 and LF21 cells exert preventive or protective effects against the Gram-negative bacteria Salm. Typhimurium and Y. enterocolitica. To better understand the mechanisms underlying the LF21-mediated and LP133-mediated protection against bacterial infection in nematodes, transcriptional profiling was performed for each experimental group. These experiments showed that genes related to energy generation and ageing, regulators of insulin/IGF-1-like signalling, DAF genes, oxidation and reduction processes, the defence response and/or the innate immune response, and neurological processes were upregulated in nematodes that had been fed heat-killed Lactobacillus cells compared with nematodes that had been fed E. coli cells.
  
  
  CONCLUSIONS
  In this study, the feeding of heat-killed Lactobacillus bacteria to Caenorhabditis elegans nematodes was shown to decrease infection by Gram-negative bacteria and increase the host lifespan. C. elegans has a small, well-organized genome and is an excellent in vivo model organism; thus, these results will potentially shed light on important Lactobacillus-host interactions.
authors.affiliation: Division of Food Bioscience and Technology, College of Life Sciences and Biotechnology, Korea University, Seoul, Korea.
authors.forename: J
authors.initials: J
authors.lastname: Lee
authors.affiliation: Division of Food Bioscience and Technology, College of Life Sciences and Biotechnology, Korea University, Seoul, Korea.
authors.forename: J
authors.initials: J
authors.lastname: Choe
authors.affiliation: Division of Food Bioscience and Technology, College of Life Sciences and Biotechnology, Korea University, Seoul, Korea.
authors.forename: J
authors.initials: J
authors.lastname: Kim
authors.affiliation: Division of Animal Science, Chonnam National University, Gwangju, Korea.
authors.forename: S
authors.initials: S
authors.lastname: Oh
authors.affiliation: School of Mechanical Engineering, Sungkyunkwan University, Suwon, Korea.
authors.forename: S
authors.initials: S
authors.lastname: Park
authors.affiliation: Division of Food Bioscience and Technology, College of Life Sciences and Biotechnology, Korea University, Seoul, Korea.
authors.forename: S
authors.initials: S
authors.lastname: Kim
authors.affiliation: BK21 Plus Graduate Program, Department of Animal Science and Institute of Agricultural Science & Technology, Chonbuk National University, Jeonju, Korea.
authors.forename: Y
authors.initials: Y
authors.lastname: Kim
mesh_terms: D000375:Aging / Q000235:genetics; D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics* / Q000502:physiology*; D004734:Energy Metabolism / Q000235:genetics; D004926:Escherichia coli / Q000502:physiology; D005786:Gene Expression Regulation; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D007778:Lactobacillus / Q000502:physiology*; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D012480:Salmonella Infections / Q000382:microbiology / Q000517:prevention & control*; D012486:Salmonella typhimurium / Q000472:pathogenicity; D015009:Yersinia Infections / Q000382:microbiology / Q000517:prevention & control*; D015008:Yersinia enterocolitica / Q000472:pathogenicity
chemical_list: D007334:Insulin-Like Growth Factor I
keywords: Caenorhabditis elegans; Lactobacillus spp.; heat-killed cells; host immunity; transcriptome analysis