A
V. campbellii overnight culture was diluted 1:100 into Kim-Epstein (KE) medium (10 mL) (56 (
link)) or lysogeny broth containing 3.5% (wt/vol) NaCl (LB35) medium (60 mL) and grown until early exponential growth phase (optical density at 600 nm [OD
600] 0.5, KE medium) or early stationary phase (OD
600 5.0, LB35). The KE medium was modified as follows: The pH was adjusted to 7.6 with the corresponding phosphate buffer, the salt concentration was increased to 2% (wt/vol) NaCl, and FeSO
4 was omitted. Compounds were added from DMSO stocks to 50 μM into a clear flat-bottom 96-well plate. Next, 200 μL bacterial culture previously diluted to OD
600 0.01 in KE medium + 20 mM NaHCO
3 or in KE medium + 20 mM NaHCO
3 supplemented with 100 μg/mL
human apo-transferrin (Sigma-Aldrich) or to OD
600 0.005 in LB35 or in LB35 supplemented with 30% (vol/vol) of
adult bovine serum (Sigma-Aldrich) was added. The plates were incubated in an
Infinite M200 Pro plate reader (Tecan) at 30 °C with continuous shaking (KE medium) or with 20 s shaking every 5 min (LB35 medium). The optical density at 600 nm was measured every 10 to 30 min. Blank values (only medium) were subtracted from data values, and data were plotted using GraphPad Prism.
Weigert Muñoz A., Hoyer E., Schumacher K., Grognot M., Taute K.M., Hacker S.M., Sieber S.A, & Jung K. (2022). Eukaryotic catecholamine hormones influence the chemotactic control of Vibrio campbellii by binding to the coupling protein CheW. Proceedings of the National Academy of Sciences of the United States of America, 119(10), e2118227119.