Monday, December 10, 2007 - 8:53 AM

Characterization of intracellular bacteria Wolbachia pipientis infection in Asian tiger mosquitoes, Aedes albopictus

Cynthia C. Khoo, and Stephen L. Dobson, University of Kentucky, Department of Entomology, S-225 Ag. Science Center North, Lexington, KY

Wolbachia are obligate intracellular bacteria that infect arthropods and other invertebrates. The efficient maternal transmission of Wolbachia coupled with multiple host reproductive modifications have resulted in their extensive spread. An ability to culture Wolbachia in vitro within insect cell cultures provides a simplified model system in which to characterize the interaction between Wolbachia and host cells. Developed in 1997, the Aa23 Wolbachia-infected Aedes albopictus cell culture provides a useful tool for investigating Wolbachia infection in vitro. The Aa23 cell culture has been used in prior studies for investigating antibiotic effects and Wolbachia genome and protein characterizations. To provide a more formal characterization, fluorescence in situ hybridization was used to examine Wolbachia infection dynamics in the Aa23 cell culture. Four passaging methods were used to maintain the Aa23 cell culture. For each method, examined criteria include: the proportion of infected cells, infection level per cell, and an examination of morphological variation between infected and uninfected cells. Comparisons of the different passaging methods show variation within and among the different treatments in their proportion of infected cells and infection level per cell. The overall dynamics in the different treatments range from relatively stable to unstable infections with periodic loss of infection. The results will be discussed relative to the composition of cells in the culture and how variation in infection level could impact Wolbachia research that utilizes Aa23 as a model system. Undergoing efforts to establish more stably Wolbachia-infected cell cultures as in vitro model systems will also be discussed.

Species 1: Diptera Culicidae Aedes albopictus (Asian tiger mosquito)
Species 2: Rickettsiales Rickettsiaceae Wolbachia pipientis