2.3. Transmission electron microscope analysis
Transmission electron microscope (TEM) analysis was carriedout as described by Lai et al. (2014). In briefly, the spores were fixedwith 2.5% formaldehyde and 2% paraformaldehyde in 0.1 mol/L sodium cacodylate buffer (SCB, pH 7.2) overnight. Gels were prepared by adding 3% low gelling temperature agarose in SCB to the pellet. After thorough rinsing with 0.1 mol/L SCB, the gels were post-fixed with 1% osmium tetroxide in 0.1 mol/L SCB for 4 h at room temperature, dehydrated with 15 min stages in a graded acetone series. The samples were embedded in spurr resin. Ultrathin sections were obtained using a diamond knife and stained by soaking in 2% uranyl acetate for 15 min, and post-stained in lead citrate for 1 min. The sections were analyzed using a JEOL 1230 transmission electron microscope (JEOL, Japan) at 80 kV.