Bacterial strains and growth conditions
B. burgdorferi low-passage virulent B31-5A4 was cultivated in
Barbour-Stoenner-Kelly II (BSK-II) complete medium at 34°C (59).
Cultures were passaged to 1 × 105 cells/ml and grown
to 1-3 × 107 cells/ml. Cell density was determined
using a Cellometer counting chamber (Nexcelom). E. coli strains,
HI-control 10G or BL21(DE3) cells, were grown overnight in lysogeny
broth (LB) at 37°C to a density of ~1
OD600. Cells were then passaged 1:100 unless stated
otherwise. Descriptions and genotypes of all strains used (E.
coli and B. burgdorferi ) can be found in Table S1.