FIG 1.
The effect of SQR on H2S accumulation, cellular sulfane sulfur, and competitiveness of PCC7002 with its mutant. (A) H2S accumulation during culture as detected in the gas phase with lead-acetate paper. 1, PCC7002; 2, PCC7002Δsqr; 3, PCC7002Δsqr::sqr. (B) Sulfane sulfur contents of PCC7002 (black bar), PCC7002Δsqr (red bar), and PCC7002Δsqr::sqr (blue bar) were detected by using SSP4 (sulfane sulfur probe 4). (C) Competition experiment of PCC7002 and PCC7002Δsqr. The abundance of PCC7002 (black bars) showed an apparent advantage over PCC7002Δsqr (red bars) after transfer 4 times. The mixing of two strains at equal cell numbers was defined as the first transfer. The time interval between each transfer was 48 h, and real-time quantitative PCR (qPCR) was done at 48 h. All data are averages from three samples with standard deviation (error bar). The experiment was repeated at least three times. ****, P < 0.0001 (paired t test).