A detailed protocol is described for imaging the real time formation of DNA repair complexes in Bacillus subtilis cells.
Trial and error are required to find exposure conditions for the highest quality images for each strain; we find that 1 millisecond is appropriate for white light images, while exposures of 100 to 2000 ms are appropriate for GFP (FITC) and FM4-64 (TRITC) images. Exposure time will vary depending on the imaging equipment used. We recommend the use of one strain per 15-well microscope slide for the simplest imaging, as pad quality and diffusion of cells from the pad border could complicate strain differentiation if multipl…
The authors wish to thank Drs. Philina S. Lee and Alan D. Grossman for initially training L.A.S. in fluorescence microscopy. The authors also thank Drs. Melanie Berkmen and Hajime Kobayashi for help and tips for imaging. This work was supported by start-up funds from the College of Literature, Science & Arts and from the Department of Molecular, Cellular, and Developmental Biology at the University of Michigan.
Specific solution recipes1:
10x S750 salts
0.5 M MOPS
100 mM Ammonium Sulfate
50 mM Potassium Phosphate Monobasic
Filter sterilize, and wrap S750 media in foil prior to storage
100x Metals
0.2 M MgCl2
70 mM CaCl2
5 mM MnCl2
0.1 mM ZnCl2
100 μg/mL Thiamine HCl
2 mM HCl
0.5 mM FeCl3*
dH2O to final volume
*FeCl3 should be added last, to prevent precipitation.
After filter sterilization, wrap 100x Metal solution in foil.
S750 media
1x S750 salts
1x Metal
1% Glucose
0.1% Glutamate
40 μg/mL Tryptophan
40 μg/mL Phenylalanine
distilled H2O to final volume
10x Spizizens (grams/L)
151.4 mM Ammonium Sulfate (20g/L)
803.8 mM Potassium Phosphate Monobasic (140g/L)
440.9 mM Potassium Phosphate Dibasic (60g/L)
34.0 mM Sodium Citrate (10g/L)
16.6 mM MgSO4 (2g/L)
dH2O to final volume
Filter sterilize