Regional differences in lectin binding to colonic epithelium by fluorescent and electron microscopy.

The distribution of glycosubstances in colonic epithelium using lectins that were rhodaminated for fluorescent microscopy or coupled to colloidal gold for electron microscopy has been studied. Findings, based on lectin binding patterns, indicate that the right, transverse, and left colon of the guinea pig differ in their content of glycoconjugates within goblet cells and along the brush border. Local variations of labeling were also observed within goblet cells between the upper and lower portions of crypts. Throughout the colon, corresponding to a region of supranuclear fluorescence, Ricin II-colloidal gold labeled the Golgi complex of both enterocytes and goblet cells. Ricin II-colloidal gold also labeled small (congruent to 800 A) vesicles in the apical portion of enterocytes in all colonic segments. Microvilli were labeled by Ricin II-colloidal gold in the right and transverse colon, a finding that correlated with the observed adhesion of bacteria in those segments.