Cells and Materials


The cationic reagents, ruthenium red (RR), alcian blue (AB) and ruthenium red -lysine were compared for ultrastructural preservation and staining of the bacterial glycocalyx. En bloc RR, AB and RR-lysine procedures, and a glutaraldehyde/OsO4 fixation withou t cationic reagent, were evaluated by transmission electron microscopy (TEM) for several methanotroph and staphylococcal species. The glutaraldehyde/OsO4 fixation was totally ineffective in preserving or staining the glycocalyx material in all species studied. The RR procedure was more effective than the glutaraldehyde/OsO4 fixation but was generally less so than the RR-lysine procedure. By the RR-lysine procedure, extensive layers that were often filamentous or fibrous were observed in the methanotrophs, and extended fibrous elaborations were seen in the staphylococci. By the AB procedure, staphylococci glycocalyx material consisted of condensed curved structures or net-like features not directly comparable to the RR-lysine images. In the methanotrophs, filamentous or fibrous layers were often comparable between AB and RR-lysine. Thus, ultrastructural observation of the bacterial glycocalyx in all species studied was improved by use of RR-lysine, whereas the use of AB showed species variation.