4.3. Microscopy Analysis of Spores

The spores were observed using an optical microscope. The planktonic and sessile cells were collected by centrifugation and fixed with heat on glass slides. The cells were stained with 5% malachite green (Daejung Chemicals and Metals Co. Ltd., Siheung, Korea), placed over a beaker on which they were heated by steam from boiling water for 30 min, after which they were rinsed with softened water. Vegetative cells were then counterstained with 2% safranine (BD) for 10 min at room temperature, and the remaining cells were rinsed with softened water. The stained cells were viewed under an optical microscope (Model Eclipse Ci-L, Nikon Corporation, Tokyo, Japan) at 1000× magnification, and analyzed using the i-Solution Lite software program (IMT i-Solution, Inc., Vancouver, BC, Canada). The dyeing experiment was performed at least in duplicates, with two independent experiments.