Schistosome Feeding and Regurgitation
Figure 2
Layout of the alimentary tract.
A. Male S. haematobium showing the distribution of black hemozoin pigment that delineates the lumen of the gut caecum (c). The mouth at the base of the oral sucker (os) opens onto a short esophagus (es, arrows) that empties into an initial transverse region of gut (tg, arrowhead). This bifurcates to pass round the testes (te) before reuniting approximately halfway down the body to continue to the extreme posterior where it ends blindly. B. Female S. japonicum from a rabbit with the gut lumen almost completely filled with dark hemozoin pigment. The layout is the same as for the male but with the bifurcated caeca (c) passing first around the egg-filled uterus (ut, arrows) and ovary (o), before uniting to form a single tube completely surrounded by vitelline follicles (inset, higher magnification, esophageal region). C. Confocal image of the anterior of a male S. japonicum from a rabbit host highlighting the esophageal gland (green), revealed by detection of esophageal-specific protein SjMEG-4.1, and the nuclei (false-colored orange) stained by DAPI. The short esophagus is lined with atypical tegument syncytium, the surface of the anterior compartment (a) being corrugated while that in the posterior (p), coincident with the gland, is extended ∼50-fold by thin plate-like extensions. Aggregates of host leucocytes (leu, arrow) are evident in the esophageal lumen. Scale bars: A, 0.75 mm mm; B, 0.5 mm (inset, 0.2 mm); C, 0.1 mm.