title: Gene expression analysis of Xenopsylla cheopis (Siphonaptera: Pulicidae) suggests a role for reactive oxygen species in response to Yersinia pestis infection.
abstract: Fleas are vectors for a number of pathogens including Yersinia pestis, yet factors that govern interactions between fleas and Y. pestis are not well understood. Examining gene expression changes in infected fleas could reveal pathways that affect Y. pestis survival in fleas and subsequent transmission. We used suppression subtractive hybridization to identify genes that are induced in Xenopsylla cheopis (Rothschild) (Siphonaptera: Pulicidae) in response to oral or hemocoel infection with Y. pestis. Overall, the transcriptional changes we detected were very limited. We identified several genes that are likely involved in the production or removal of reactive oxygen species (ROS). Midgut ROS levels were higher in infected fleas and antioxidant treatment before infection reduced ROS levels and resulted in higher bacterial loads. An ROS-sensitive mutant strain of Y. pestis lacking the OxyR transcriptional regulator showed reduced growth early after infection. Our results indicate that ROS may limit Y. pestis early colonization of fleas and that bacterial strategies to overcome ROS may enhance transmission.
authors.affiliation: Department of Microbiology and Molecular Biology, Brigham Young University, WIDB 893, Provo, UT 84602, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhou
authors.forename: Colin W
authors.initials: CW
authors.lastname: Russell
authors.forename: Kody L
authors.initials: KL
authors.lastname: Johnson
authors.forename: Richard D
authors.initials: RD
authors.lastname: Mortensen
authors.forename: David L
authors.initials: DL
authors.lastname: Erickson
mesh_terms: D000818:Animals; D020869:Gene Expression Profiling; D010930:Plague / Q000635:transmission; D017382:Reactive Oxygen Species / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D005423:Siphonaptera / Q000378:metabolism / Q000382:microbiology*; D015010:Yersinia pestis / Q000502:physiology*
chemical_list: D017382:Reactive Oxygen Species