Skip to main content
. 2011 Apr 18;2:79. doi: 10.3389/fmicb.2011.00079

Figure 2.

Figure 2

Production of extracellular sulfur globules by A. ferrooxidans during incubation under oxygen-limiting conditions. (A) A. ferrooxidans was grown in thiosulfate under OSC and the changes in concentrations of thiosulfate (■) and tetrathionate (▲) during A. ferrooxidans cell growth (●) were determined. To study the effect of oxygen limitation, thiosulfate-grown A. ferrooxidans cultures were either shifted to OLC or kept under OSC at the point of the growth curve shown by an arrow. (B) Generation of elemental sulfur as detected by the increase in the absorbance at 430 nm in A. ferrooxidans cultures. Three A. ferrooxidans cultures were grown in thiosulfate until the late-exponential-phase. One culture was subjected for 16 h to OSC and another one to OLC. The third culture was filtered (0.22 μm-filter) and the medium obtained was incubated for 16 h under OLC and was used as the “No Cells” control. (C) Phase-contrast micrographies (600 × magnification) of A. ferrooxidans cells from OLC- and OSC-incubated cultures shown in (B). (D) Cell growth of A. ferrooxidans cultures (●,○) and percentages of sulfur globules produced (▼,∇) during OSC- (●,▼) or OLC- (○,∇) incubations.