Figure 1.
Morphology of Schistosoma mansoni and Schistosoma japonicum eggs.
Panel A shows an intact egg of S. mansoni. Panel B shows an S. mansoni egg broken open with the miracidium still inside the egg. Panels C and D show similar images for S. japonicum.
Figure 2.
Surface characteristics of Schistosoma mansoni and S. eggshells.
Panels A and B show the surface ofjaponicum a S. mansoni egg imaged with high resolution scanning electron microscopy illustrating that the surface is completely covered with filaments or microspines. Figures C and D show similar observations of S. japonicum. The microspines on the surface of S. japonicum are shorter and the surface is covered with an additional filamentous matrix.
Figure 3.
Iron localization within the Schistosoma eggshell.
Panel A shows inclusions of iron phosphate in the shell of S. mansoni at low resolution. Panel B shows similar inclusions in S. mansoni at a higher resolution. Panel C depicts the STEM-EDS spectra for iron, phosphorous and oxygen acquired when scanning across an inclusion, along the white line (d) shown in Panel B. Panels D, E and F show similar observations for S. japonicum.
Figure 4.
Results of magnetic susceptibility analysis.
Figure 4A shows the curve fits of the Brillouin function with diamagnetic contribution (Equation 1) to the magnetization versus magnetic field data (for whole eggs at a temperature of 5 K). It can be seen that ideal paramagnetic behavior is approximated with good precision. (R2>0.99) for both, Schistosoma mansoni and Schistosoma japonicum eggs. Figure 4B shows the curve fits of Curie's law to the magnetization versus inverse temperature data. Again, ideal paramagnetic behavior can be observed. For S. mansoni the total magnetic moments were approximated to 4.84×μB using the Brillouin function and 4.76×μB using Curie's law. For S. japonicum the total magnetic moments were approximated to 4.12×μB using the Brillouin function and 3.71×μB using Curie's law.
Table 1.
Elemental concentration in Schistosoma mansoni and Schistosoma japonicum eggs.
Figure 5.
Schistosoma mansoni egg – paramagnetic microsphere conjugates.
At least 15 microspheres can be seen bound to the surface of the egg. A magnet is rotated around the suspension by 180 degrees over approximately 0.5 seconds (black arrows indicate the movement of the magnet). The images represent frame captures from Video S1 available as supporting information.
Figure 6.
Microsphere binding characteristics to S. mansoni and S. japonicum eggs.
Panel A shows the fraction of eggs that had at least one microsphere bound at an egg to microsphere ratio of 1∶100. Panel B shows the distribution of the number of microspheres bound to eggs of the two parasite species at an egg to microsphere ratio of 1∶100. Panels C and D show the same data for an egg to parasite ratio of 1∶500. For both ratios S. japonicum eggs spontaneously conjugated with microspheres at a significantly higher frequency than S. mansoni eggs. Similarly, the average number of microspheres per individual egg was considerably higher for S. japonicum than for S. mansoni (Panels B and D).