FIG. 2.

H. volcanii swims in a flagellum-dependent manner. (A) H. volcanii H98 (wt) was stab inoculated into complex medium (CX) or defined medium (CDM or CA medium), while the ΔaglB mutant was stab inoculated into only CX (0.3% agar). Cells were then incubated for three days. (B) H. volcanii H98 (wt) transformed with pRV1-ptna (ptna) or pMT1 (ptna-flgA1-flgA2), MT1 (ΔflgA1 ΔflgA2) transformed with pRV1-ptna or pMT3 (ptna-flgA1-flgA2), or MT3 (ΔpibD) transformed with pRV1-ptna or pMT4 (ptna-pibD) was stab inoculated into complex (CX-tryptophan) medium containing novobiocin (0.3% agar). Cells were incubated at 45°C for 5 days. Note that growth of H. volcanii is significantly slower in medium containing novobiocin. Strains lacking flagellins or PibD did not produce halos, even after 14 days of incubation (data not shown).