Schistosoma mansoni: ultrastructural observations on the small intestine of murine host

Between 6 and 29 weeks, the small intestines of mice infected with Schistosoma mansoni were studied with the electron microscope. Granulomas were confined to the serosal-muscularis regions of the small intestine. Early granulomas were characterized by having several cell types with the most conspicuous type being the eosinophil. Older granulomas were more fibrotic. These were compared with hepatic granulomas of comparable age. In the vicinity of active eggs either in granulomas or in the lamina propria, mitochrondria from epithelial cells displayed intracristal granules. Intraperitoneal injections of soluble egg antigen isolated from viable S. mansoni eggs produced identical mitochondrial abberations. Cytochrome c-cytochrome oxidase activity was visualized in the mitochondria by the diaminobenzidine method.     

Haematoloechus medioplexus: light and electron microscope localization of dipeptidyl aminopeptidases I and II in the gastrodermis

The exopeptidases, dipeptidyl aminopeptidases I and II (EC 3.4.14.1 and EC 3.4.14.2, respectively) were demonstrated cytochemically at light and electron microscope levels in the gastrodermis of adult Haematoloechus medioplexus recovered from the lungs of naturally infected Rana pipiens. Lys-Ala-4-methoxy-beta-naphthylamide and Pro-Arg-4-methoxy-beta-naphthylamide were used as specific substrates. Reaction products from both enzymes were observed in the gastrodermis in what are believed to be vesicles analogous to secondary lysosomes. The localization of the enzymes in these vesicles coincides with previous reports of the distribution of acid phosphatase and esterase activities. The hydrolases are believed to function both intracellularly by autophagy and extracellularly by digestion of host globin in the cecal lumen. Cathepsin B activity was not observed following the cytochemical protocol used in this investigation.     

The effect of colchicine on translocation of incorporated [3H] proline in Hymenolepis diminuta

Portions of adult Hymenolepis diminuta were exposed to a fixed concentration of colchicine (5 X 10(-4) M) in order to determine its effect upon incorporation of [3H] L-proline. Additional studies of the effect of colchicine upon tegumental morphology were performed. Autoradiographs showed a significant decrease in amount of incorporated label in the distal tegument of colchicine tissue and a heavy accumulation of label in the parenchyma. Radioassays indicated that the effect of colchicine on proline-incorporated protein was qualitative rather than quantitative suggesting that colchicine inhibits translocation in the tegument. It was hypothesized that microtubules within the internuncial processes facilitate movement of cell products from tegumentary cytons to the body surface.     

The in vitro effects of various lysosomotropic agents on the gut of Schistosoma mansoni schistosomula

Cultured Schistosoma mansoni schistosomula of various ages were exposed to several lysosomotropic agents. Weak bases such as chloroquine, ammonium chloride, and acridine orange caused gut swelling upon protonation. The latter compound fluoresced a bright orange indicating the acidic nature of the gut contents. Hydrolysis of ingested L-amino acid methyl esters also resulted in gut swelling, indicating the nonpermeant nature of the resulting L-amino acids. Neither age nor feeding status influenced these swelling effects. Treatment of schistosomula with D-amino acid esters, free L-amino acids, or methanol had no effect. Thin-layer chromatographic analysis of worms treated with radiolabeled L-leucine methyl ester provided evidence that the ester was hydrolyzed. These results support the premise that the schistosome gut is an acidic compartment and is reminiscent of a secondary lysosome in its reaction to lysosomotropic agents.     

Application of the FITC-anti-FITC-gold system to ultrastructural localization of antigens

We report the application of a fluorescein isothiocyanate (FITC)-anti-FITC method to localize antigens at the ultrastructural level. In the systems studied, the anti-FITC-based detection method displays high specificity and sensitivity. These observations, combined with ease of production and with availability of FITC-protein conjugates, suggest that the FITC-anti-FITC method is a good alternative to presently used methods and is widely applicable to immunochemical and immunocytochemical procedures. The same preparation and protocol can be used for light and electron microscopic studies, thereby reducing possible artifacts introduced if different procedures are used. In the present study, two systems were used to test the method. One system used an FITC-labeled monoclonal antibody (MAb) to schistosome circulating cathodic antigen. In this system, the label was detected in the gut of adult Schistosoma mansoni by an anti-FITC MAb conjugated to 10-nm gold particles. The second system used human IgM antibodies pooled from patients infected with Schistosoma mansoni. In this system detection was accomplished using an anti-human IgM-FITC conjugate followed by the anti-FITC-Au antibody conjugate.