PEGylation of olive pollen OBs and immunodetection of caleosin by Western blotting. Oil bodies were isolated from olive pollen, incubated with PEG-MAL (5,000 Da), run on a 7.5% polyacrylamide Bis-Tris gel and transferred onto a PVDF membrane. Oil body-associated caleosin was immunodetected using an αN anti-Clo3 Ab, followed by an anti-rabbit IgG-DyLight 549 conjugated secondary Ab. One prominent higher molecular weight band (arrow), which corresponds to one modified Cys residue, was visible in PEGylated OBs but not in the control (i.e. non-PEGylated OBs).