Name: Michael Dumas

Email: dumsmd@udel.edu

Author: Michael Dumas

Author affiliation: University of Delaware, Delaware Biotechnology Inst.

Abstract title: Dehalophage Dynamics in Dehalococcoides Sp. Strain BAV1 Cultures

Absstract:

Dehalophage Dynamics in Dehalococcoides Sp. Strain BAV1 Cultures Dehalococcoides (Dhc) sp. are unique bacteria relevant for bioremediation due to their ability to respire chloro-organic environmental contaminants. Dhc sp. strain BAV1 is able to metabolize dichloroeed with quantitative real-time PCR. Gas chromatography headspace analysis was used to measure dechlorination activity. In treatment cultures dechlorination of cis-DCE to VC began 4.5 weeks after phage removal concurrent with increases in both phage and host cell abundance. Between 4.5 and 8 weeks, phage particles increased 51% and BAV1 cell numbers doubled. Microscopic observation suggested a distinct shift in BAV1 cell morphology during this time period in which extracellular secretions were common. A slight increase in cell numbers (1.5-fold) was also observed in reconstituted control cultures, but no dechlorination activity nor increase in phage abundance occurred. Cells in control cultures did not show changes in cell morphology. Evidently, dynamic interactions exist between phage and Dhc host during dechlorination activity. Elucidating these phage-host relationships will shed light on Dhc biology and have practical implications for bioremediation applications. thenes and the carcinogen vinyl chloride (VC) to produce harmless ethene and inorganic chloride. Previous experiments found that BAV1 contains a non-inducible phage with a high frequency of infection (~40%). To elucidate the nature of this phage-host relationship and its implications for Dhc dechlorination activity and survival, BAV1 cells were sampled over a 16-week period from cis-1,2-dichloroethene (cis-DCE) fed cultures. Dhc cultures were separated from free phage using tangential flow diafiltration (TFD) performed inside an anoxic chamber. TFD-treated control cultures were reconstituted with filter permeate containing phage particles. Epifluorescence microscopy was used to enumerate phage and bacteria, as well as observe changes in BAV1 cell morphology. Cell numbers were also monitor.