title: Demonstration of the glycocalyces associated with three oral gram-negative bacterial species using a modern acrylic resin technique.
abstract: The complex highly hydrated chemical composition of the bacterial glycocalyx renders it difficult to preserve and visualize at the ultrastructural level. Polyanionic stains such as ruthenium red help to maintain some structural integrity, and other more modern approaches include antibody stabilization, lectins, and the addition of lysine to the primary fixative. It has been suggested that the glycocalyx of certain disease-associated organisms may play a role in the pathogenesis of some microbially based diseases such as periodontitis. New, more adequate, modern methodologies are therefore required for the further study of this structure. In the present study a cold dehydration process in conjunction with LR white acrylic resin has been employed to study the glycocalyces of three oral gram-negative bacterial species reported to be periodontopathogens. When compared with organisms processed conventionally and with ruthenium red, the organisms processed by the cold dehydration and LR white method demonstrated a fibrous matrix that was not seen in the other specimens. These results indicate that a combination of reduced dehydration temperature and cold acrylic resin embedding provides the best methodology for the visualization of the fine structure of the bacterial glycocalyx. This approach may be particularly useful in the study of organisms within specific disease-associated environments such as the periodontal pocket.
authors.affiliation: Electron Microscopy Unit, Institute of Dental Surgery, London, United Kingdom.
authors.forename: P M
authors.initials: PM
authors.lastname: Barber
authors.forename: J M
authors.initials: JM
authors.lastname: Fletcher
authors.forename: H N
authors.initials: HN
authors.lastname: Newman
mesh_terms: D000180:Acrylic Resins; D016976:Aggregatibacter actinomycetemcomitans / Q000648:ultrastructure; D001431:Bacteriological Techniques; D003080:Cold Temperature; D016124:Eikenella corrodens / Q000648:ultrastructure; D006023:Glycoproteins / Q000648:ultrastructure*; D006090:Gram-Negative Bacteria / Q000472:pathogenicity / Q000648:ultrastructure*; D006801:Humans; D008854:Microscopy, Electron; D009055:Mouth / Q000382:microbiology*; D010518:Periodontitis / Q000209:etiology; D011134:Polysaccharides / Q000032:analysis; D016966:Porphyromonas gingivalis / Q000648:ultrastructure; D012430:Ruthenium Red; D013194:Staining and Labeling / Q000379:methods
chemical_list: D000180:Acrylic Resins; D006023:Glycoproteins; D011134:Polysaccharides; D012430:Ruthenium Red