Apoptosis-like cell death induced by Salmonella in Acanthamoeba rhysodes.
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.
Feng
Ye
Y
James D. Watson Institute of Genome Sciences, Zhejiang University, Hangzhou, China.
Hsiao
Yi-Hsing
YH
Chen
Hsiu-Ling
HL
Chu
Chishih
C
Tang
Petrus
P
Chiu
Cheng-Hsun
CH
D000048:Acanthamoeba / Q000382:microbiology*; D000818:Animals; D017209:Apoptosis; D015964:Gene Expression Regulation, Bacterial; D050296:Microbial Viability; D012486:Salmonella typhimurium / Q000235:genetics / Q000254:growth & development