Fig 4.

Rare earth element susceptibilities of B. subtilis strains. B. subtilis strains 168 (wild type), TI392 (uppS86), and TI393 (bcrC) were grown in L medium at 37°C for 4 h. Then, aliquots of 2 μl of cell suspension were spotted onto rare earth element-free medium (A) and medium containing each rare earth element at the indicated concentration (B to P), followed by incubation at 37°C for 18 h. The rare earth elements used were all chloride salts. Abbreviations: Y, yttrium; La, lanthanum; Ce, cerium; Pr, praseodymium; Nd, neodymium; Sm, samarium; Eu, europium; Gd, gadolinium; Tb, terbium; Dy, dysprosium; Ho, holmium; Er, erbium; Tm, thulium; Yb, ytterbium; Lu, lutetium.