Measuring intracellular ROS:

Protocol:

1.) Grow 5mL overnight cultures of the strains to be tested.

2.) The following day, dilute back the cultures 1:100 into fresh media.

3.) Grow the cells to mid-exponential phase (OD = ~0.5). At this point, you may want to add an ROS elicitor to your culture (ex, H2O2, K₂TeO_3,

4.) Stress ce

Overnight culture was passaged 1 : 100 into fresh medium.

Monitor the obsorbance to 0.2-0.4.

Exposed to K₂TeO₃ (0.5 µg/ml) for 30 min.

Centrifuge at 3,000 g for 5 min at 4°C , cells were washed with ice chilled saline phosphate buffer (137 mM NaCl 2.7 mM KCl, 10 mM Na₂HPO₄ , 2mM KH₂PO₄, pH 7.3) and resuspended with two volume of the same buffer, conducted at 4°C .

Cells were incubated with 100 uM (50 µg/ml) 2’,7’-dihydrodichlorofluorescein diacetate at 37°C for 60 min in water bath.

Centrifuge at 3,000 g for 5 min at 4°C. Wash once with ice chilled PBS. Centrifuge and put on ice before run flow.

Fluorescence intensity was determined by flow cytometry.

-- Main.XueZhang - 25 May 2017