FIG 1 .

Cellular morphology of C. metallidurans strain Δ7 and its parent strain AE104. Parent strain AE104 (A and B) and strain Δ7 (C and D) were cultivated in TMM. Thirty-one percent of the AE104 cell sections (n = 85) contained grayish particles; three cell sections contained one large particle that filled the section to a large extent (A, arrow). AE104 cell sections contained only small single electron-dense particles (B, arrow). The number of Δ7 cell sections containing grayish particles was similar to that of the AE104 cells (28%, n = 118). Differences between the AE104 and Δ7 particles were most likely preparation artifacts (A and C, arrows). An 8.5% proportion of the Δ7 cell sections contained one or more electron-dense particles (D, arrow) that displayed a higher electron density and a larger diameter than the electron-dense particles in strain AE104 (B, arrow). Bars, 0.3 µm (D) or 0.5 µM (A to C).