Phenotypic Variance at an Interface from Environmentally-Isolated Bdellovibrio bacteriovorus

Abstract

Under certain conditions, predatory Gram-negative Host-Dependent (HD)Bdellovibrio bacteriovorus undergoes morphological and physiological changes resulting in an axenic phenotypic variant termed Host-Independent (HI)Bdellovibrio. This facile switch from HD to HIBdellovibrio(and back again)has been demonstrated in lab culturedBdellovibrio bacteriovorus109 J trapped at an interface by our group. Itwas wondered if bdellovibrios in the environment also possess this phenotypic plasticity. To test this hypothesis, HDBdellovibriowas extracted and enriched from sewage water and then purified using traditional microbiological techniques. Subsequently, purified HDBdellovibriowas trapped at an interface and the HD cells changed to the HIvariant as measured by standard culturing techniques and fluorescence in situ hybridization (FISH). Theseresults will be presented and indicate that conversion from HD to HIBdellovibriocan be measured with both lab and environmental strains. In addition, preliminary atomic force microscopic data will be presented that track the morphology of this dynamic flip from HD to HI on a surface. The larger question still remains as to how and where in the environment this bacterium utilizes phenotypic variance.