title: Apoptosis-like cell death induced by Salmonella in Acanthamoeba rhysodes.
abstract: Free-living amoebae act as environmental hosts of several intracellular pathogens. We examined the interaction between Acanthamoeba rhysodes and Salmonella, a human intracellular pathogen. There was no difference among three different serovars of Salmonella in terms of their growth within A. rhysodes over time. The number of intracellular bacteria increased at 6 h post-infection, and the viability of A. rhysodes was significantly reduced at 24 h post-infection. Amoebic cell death was characterized by TUNEL and Annexin V assay, without DNA ladder identified, indicating an apoptosis-like cell death in Salmonella-infected A. rhysodes. Global gene expression screening between intracellular and extracellular Salmonella by microarray and quantitative PCR showed that genes from Salmonella pathogenicity islands and virulence plasmid were up-regulated within A. rhysodes. The phase-dependent expression pattern suggests their distinct roles in the pathogenesis. A. rhysodes and Salmonella provide a model to study transient symbiosis between bacterial pathogens and protozoa in an aquatic ecosystem.
authors.affiliation: James D. Watson Institute of Genome Sciences, Zhejiang University, Hangzhou, China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Feng
authors.forename: Yi-Hsing
authors.initials: YH
authors.lastname: Hsiao
authors.forename: Hsiu-Ling
authors.initials: HL
authors.lastname: Chen
authors.forename: Chishih
authors.initials: C
authors.lastname: Chu
authors.forename: Petrus
authors.initials: P
authors.lastname: Tang
authors.forename: Cheng-Hsun
authors.initials: CH
authors.lastname: Chiu
mesh_terms: D000048:Acanthamoeba / Q000382:microbiology*; D000818:Animals; D017209:Apoptosis; D015964:Gene Expression Regulation, Bacterial; D050296:Microbial Viability; D012486:Salmonella typhimurium / Q000235:genetics / Q000254:growth & development