ATP-Binding Cassette Transporters Amino Acid Sequence Animals Bacterial Proteins Biological Transport, Active Brucella abortus Cell Membrane ChoX protein Choline Female Gene Expression Regulation, Bacterial Macrophages Mice Mice, Inbred BALB C Molecular Sequence Data Open Reading Frames Phosphatidylcholines article binding affinity binding assay cell migration cell vacuole choline choline uptake controlled study fluorescence gene disruption isotope labeling mutant nonhuman