Ultrastructure of the adhesion of bacteria to the epithelial cell membrane of three-day postnatal rat tongue mucosa: a transmission and high-resolution scanning electron microscopic study

Togue mucosa surface of 3-day postnatal rats was examined under transmission electron microscopy (TEM) and high-resolution scanning electron microscopy (HRSEM). For HRSEM analysis, the specimens were fixed in the same solution for 24 h, postfixed in 2 percent osmiun tetroxide, critical-point dried and coated with platinum-palladium. For TEM analysis, the specimens were fixed using modified Karnovsky solution and embedded in Spurr resin. The results revealed the presence of numerous microplicae in the membrane surface of keratinized epithelial cells to which groups of bacteria were attached. These bacteria were staphylococcus and coccus organized either in rows or at random, which were visualized in three-dimensional HRSEM images. At high magnification, the TEM images revealed the adhesion of bacteria to the cell membrane through numerous filamentous structures comprising the glycocalyx. The fine fibrillar structures rising from each bacterium and from cell membrane were clearly seen. These characteristics on bacteria structure may be used for future control or prevention of bacterial diseases and for installation of the oral native flora.

A superfície lingual de ratos de três dias de idade foi examinada em microscópia eletrônica de transmissão (MET) e em microscópia eletrônica varredura de alta resolução (MEVAR). Para o método de MEVAR, os espécimes foram fixados na mesma solução por 24 h, pós fixados em solução de tetróxido de ósmio a 2 por cento, secos em ponto crítico e cobertos com platina- paládio. Para análise em MET, os espécimes foram fixados utilizando-se solução de Karnovsky modificada e emblocadas em resina Spurr. Os resultados mostraram a presença de numerosas micropregas na membrana superficial das células epiteliais queratinizadas, nas quais estavam aderidos grupos de bactérias. Estas bactérias eram estafilococos e cocos, organizados em fileiras ou a esmo, e puderam ser observadas em imagens tri-dimensionais em MEVAR. Em maiores aumentos, as imagens em MET revelaram a adesão de bactérias nas células por meio de numerosas estruturas filamentares compondo o glicocálice. As delicadas estruturas filamentares na periferia das bactérias e das células foram nitidamente identificadas. Estas características da estrutura bacteriana podem ser utilizadas, no futuro, para controle e prevenção de doenças bacteriana, bem como para a instalação da flora oral nativa.

Ultrastructural aspects of the muscle of theanterior third of rabbit

The structural organization of the anterior third of adult rabbit tongue was studied using light microscopy andconventional and high resolution scanning electron microscopy. Histologically, the muscle layer of the tongue consistedof muscle fibers arranged vertically, transversally and longitudinally. These fibers were surrounded by connectivetissue containing bundles of collagen fibers that formed the endomysium and the perimysium. Capillary blood vesselswere noted in the connective tissue between muscle fibers. Silver impregnation demonstrated the presence of numerousbundles of nerve fibers distributed irregularly around the muscle fibers. High-resolution scanning electron microscopyshowed that the sarcoplasm of the muscle cells consisted of bundles of myofilaments arranged longitudinally andnumerous mitochondria.

Scanning electron microscopy of the rat tongue mucosa with special attention to bacteria on epithelial cell membranes / Microscopia eletrônica de varredura da mucosa da língua de ratos com enfoque em bactérias em menbranas de células epiteliais

The authors examined the filiform and fungiform papillae surfaces of rat tongue by scanning electron microscopy showing the numerous groupings of bacteria on the epithelial cell membranes. The fungiform papillae were round in shape and presented few bacteria. The epithelial cell of filiform papillae revealed numerous streptococci. The grouping of the bacteria are attached on the epithelial cell membrane, demonstrating three-dimensional SEM images