Movement of Entamoeba histolytica trophozoites in rat cecum and colon intact mucus blankets and harvested mucus gels
Leitch, G.J.; Harris-Hooker, S.A.; Udezulu, I.A.
American Journal of Tropical Medicine and Hygiene 39(3): 282-287
1988
ISSN/ISBN: 0002-9637 PMID: 2902807 Document Number: 324258
E. histolytica trophozoites were centrifuged into mucus gels harvested in vivo loops of rat caecum and proximal colon. Obvious amoebic movement was not detected in the colonic mucus, but attenuated motility was measured in the caecal mucus. The harvested rat caecal mucus had significantly lower apparent viscosity and neutral glycoprotein concentration values than the colonic mucus. A shape factor method was developed to assess the motility of amoebae in mucus gels and intact mucus blankets. Shape factor data obtained from harvested mucus gel and intact mucus blanket experiments indicated that such mucus severely attenuated trophozoite movement with the attenuation being greater with colonic than with caecal mucus. Entamoeba trophozoites are known to be able to generate a pseudopod force of 3.3 x 10-6 Newtons. Latex microspheres of the size range of Entamoeba trophozoites were forced through caecal and colonic mucus gels under gravity. Colonic mucus gels could withstand a force a 3.3 x 10-6 Newtons while caecal mucus could not, suggesting that the amoebic movement that was observed in caecal mucus involved mechanical penetration of the mucus by the amoeba pseudopodia and did not require prior gel dissolution by Entamoeba enzymes. The authors present experiments that suggest that the movement of Entamoeba histolytica trophozoites observed in rat caecal mucus (but not observed in colonic mucus) involved mechanical penetration by pseudopodia and was not dependent on degradation of the mucus by trophozoite enzymes.Carolyn A. Brown.