COA, but not N<sub>2</sub>A, results in S-phase arrest of cell cycle. ToobiakShlomi ShaklaiMati ShaklaiNurith 2013 <p>Cells were incubated under aerobic and anaerobic conditions, N<sub>2</sub>A or COA, for 4 days. Insert: representative FACS analysis of cell cycle for K562 cells incubated under different atmospheres. Arrows indicate center of S-phase. Main Figure: phase distribution of viable cells. Mean ± SD from 3 independent experiments is shown. Empty bars - G<sub>0</sub>/G<sub>1</sub> phase, black bars - S phase and grey bars - G<sub>2</sub>/M phase.</p>