Bile Acid Chemotaxis Preparation

The chemoattractant (bovine bile) was prepared in chemotaxis buffer (CB; sodium phosphate buffer (50 mM; pH 7.0), disodium ethylenediaminetetraacetic acid (EDTA) (10 µM), and glycerol (0.05% (w/v)) [30 (link)]. To obtain physiology relevant concentrations [24 (link),31 (link)], bile was diluted in CB in a series of 10-fold dilutions from 3% to 0.0003% (w/v). All studies were performed using bovine bile since human and bovine biles have similar compositions, but with different proportions of bile acids [32 (link),33 (link)]. All bile solutions were mixed with 2% (w/v) low-melting-temperature-agarose (NuSieve GTG, Lonza) and were drawn into a 1 μL microcapillary tube in preparation for chemotaxis experiments.