Stereo architecture of the connective tissue cores of the lingual papillae in the treeshrew (Tupaia glis).

Summary The stereo architecture of the lingual connective tissue cores (CTC) in the treeshrew (Tupaia glis) (which has the primitive characteristics of primates) was observed by scanning electron microscopy, and compared to that of other animal orders. The tongue of the treeshrew has three vallate papillae which are situated in the posterior part of the tongue, while some macaques have several vallate papillae. Among numerous filiform papillae, fungiform papillae are sporadically distributed. A filiform papilla consists of a bundle of several slender spine-like processes arranged in a circle at the basal margin. After removal of the epithelium, the CTC of the filiform papilla looks like a human hand raised with the palm facing towards the tongue tip. The fungiform CTC in the threeshrew is columnar in shape (rather similar to that of Insectivora and Rodentia) and at the top there are several round depressions for taste buds. In the treeshrew several large rod-shaped processes are derived from the postero-lateral margin of the tongue, as in Carnivora (dogs and cats), where foliate papillae are located in many other animal species. The treeshrew has numerous characteristics similar to those of the crab-eating macaque (Primates), but at the same time it has some characteristics similar to those of Insectivora, Rodentia, Carnivora and Artiodactyla.     

Newly developed technique for dual localization of keratins 13 and 14 by fluorescence immunohistochemistry

It is difficult to visualize histological details on semi-ultrathin sections by light microscopy after immunohistochemical labeling because the histological structures in such sections cannot be distinguished by standard counterstaining. To solve this problem and to visualize the immunoreactivity of keratins 13 (K13) and 14 (K14), we used a newly developed technique for dual localization of antigens by fluorescence immunohistochemistry and confocal laser-scanning microscopy in transmission mode, after staining specimens with toluidine blue. Using this approach, we examined the immunolocalization of K13 and K14 on the lingual epithelium of fetal and juvenile rats by immunofluorescence while monitoring morphological changes in the filiform papillae by laser-scanning microscopy, in transmission mode, of the same sections. No K13 and K14 immunoreactivity was detected on the lingual epithelium of fetuses on day 15 after conception (E15), at which time the lingual epithelium was composed of a few layers of cuboidal cells. K14 immunoreactivity was first detected on the lingual epithelium of fetuses on E17 and K13 immunoreactivity on E19. The number of layers of cuboidal cells in the lingual epithelium also increased from E17 to E19. K13 and K14 immunoreactivity was distinct at all postnatal stages examined. Although the respective patterns of K13 and K14 immunoreactivity differed as the filiform papillae developed, K13 immunoreactivity was generally evident in the suprabasal cells of the interpapillary cell columns and K14 immunoreactivity was detected in the basal and suprabasal cells of the papillary and interpapillary cell columns. Our newly developed technique for dual localization of antigens should be useful for investigations of very small specimens, such as fetal tissues and organs.     

Production and characterization of a monoclonal antibody against recombinant glutathione S-transferase (GST) of Fasciola gigantica

A monoclonal antibody (MoAb) against a recombinant glutathione S-transferase (rGST) of F. gigantica was produced in BALB/c mice. Reactivity and specificity of this monoclonal antibody was assessed by ELISA and immunoblotting. Six stable clones, namely 3A3, 3B2, 3C6, 4A6, 4B1 and 4D6 were obtained, All these MoAb reacted with rGST and native GST at a molecular weight of 28 kDa and found to be IgG1, kappa-light chain isotypes. These MoAb cross-reacted with Schistosoma mansoni and Schistosoma japonicum antigens at molecular weights of 28 and 26 kDa, respectively, but no cross-reactions were detected with antigens of Eurytrema and Paramphistomum spp. The localization of GST in metacercaria, 7-week-old juvenile and adult F. gigantica was performed by immunofluorescence technique, using MoAb as well as polyclonal antibody (PoAb) to the native protein as probes. In general, all clones of MoAb gave similar results and the pattern was quite similar to staining by PoAb. The fluorescence was intense, which implied the presence of a high concentration of GST in the parenchymal tissue in all stages of the parasite. However, the parenchymal cells were not evenly stained which implied the existence of subpopulations of this cell type with regard to GST production and storage. In addition, in adult and juvenile stages a moderate fluorescence was present in the basal layer of the tegument, while light fluorescence was observed in the caecal epithelium, cells in the ovary, testis and vitelline gland of the adult. In the metacercaria stage, in addition to parenchymal tissue, the tegument and tegumental cells were stained relatively more intense with MoAb and PoAb than in other stages.