Ht 7800

Cladocopium (C3) cells were collected in 3, 14, and 35 days. To transmission electron microscopy (TEM) analysis, cells were fixed 2.5% glutaraldehyde in 0.1 M cacodylate buffer and 1.75% NaCl, pH 7.2 for 24 h. Scanning electron microscopy (SEM), cells adhered to Poly-L -lysine-coated (mol wt 300,000) glass coverslips and fixed for 1 h in the same solution previously described. After fixation, cells were washed in 0.1 M cacodylate buffer and postfixed for 1 h in 1% OsO4 containing 0.8% potassium ferrocyanide in 0.1 M cacodylate buffer (pH 7.2). Then for TEM analysis, the samples were washed in 0.1 M cacodylate buffer, dehydrated in acetone, and embedded in Epon. Ultrathin sections were stained with uranyl acetate and lead citrate and observed using Hitachi HT 7800 and Fei Tecnai Spirit transmission electron microscope. To SEM after postfixed with OsO4, cells were dehydrated in ethanol and critical point dried with liquid CO2. Finally, cells were coated with a 5 nm-thick layer of platinum and observed using a Zeiss Auriga 40 scanning electron microscope.

Stock solutions of PS beads labeled with Nile blue (NB) and 4-chloro-7-nitro-1, 2, 3-benzoxadiazole (NBD-Cl) were purchased from Tianjin Da’e Scientific Co., Ltd. (China). We used 0.2-µm red and green fluorescent polystyrene (PS) beads with high-intensity fluorescence at excitation/emission wavelengths of 635/680 nm and 480/515 nm, respectively. The microstructure of PS beads, which were all spherical, was examined using environmental scanning electron microscopy (SEM: FEI Quanta 450 FEG FESEM) under high vacuum conditions and the PS beads appeared regular sphericalundera transmission electron microscope (TEM, HT7800) (Fig. 1).