Hemozoin formation in Echinostoma trivolvis rediae

Area of Science:

• Parasitology
• Biochemistry
• Materials Science

Background:

• The trematode Echinostoma trivolvis, found in Helisoma trivolvis snails, produces a black pigment within its redial stage.
• Plasmodium falciparum, a malarial parasite, produces hemozoin, a heme crystal, during its intraerythrocytic stage.

Purpose of the Study:

• To characterize the black pigment produced by Echinostoma trivolvis rediae.
• To determine if this pigment is a heme crystal and compare it to Plasmodium falciparum hemozoin.
• To investigate heme crystal formation in Echinostoma caproni.

Main Methods:

• Pigment purification and solubility testing (detergent, weak base).
• Laser desorption mass spectrometry (LDMS) to detect heme.
• Polarized light microscopy and field emission in-lens scanning electron microscopy (FEG-SEM) for crystal morphology.
• Fourier Transform Infrared (FTIR) spectroscopy for crystal structure identification.
• Seeding experiments to observe crystal growth.

Main Results:

• The black pigment from E. trivolvis rediae exhibited insolubility characteristics similar to P. falciparum hemozoin.
• LDMS confirmed the presence of heme in the purified pigment.
• Microscopy revealed irregular ovoid crystals (200-300 nm) that were birefringent.
• FTIR analysis identified the crystals as beta-hematin, a crystalline form of heme.
• Rediae of E. caproni did not produce measurable heme crystals.

Conclusions:

• Echinostoma trivolvis rediae synthesize beta-hematin crystals within the snail intermediate host.
• This represents heme crystal formation in a non-vertebrate host, distinct from Plasmodium falciparum.
• The ability to form heme crystals may vary between echinostome species or be dependent on host factors.