Résumé
The microsomal fraction from the log phase of Entamoeba histolytica cells contains Ins(1,4,5)P3 and Ins(1,3,4,5)P4 binding activity. The binding proteins/receptors for both Ins(1,4,5)P3 and Ins(1,3,4,5)P4 were purified and found to be specific for each ligand. The molecular masses for native proteins for InsP3 and InsP4 are 138 kDa and 130 kDa respectively having subunits of 69 kDa and 64 kDa respectively. That these proteins are associated with Ca2+ release was confirmed by including these proteins separately in proteoliposomes and adding InsP3 and InsP4 in both the cases.
Sujets)
Animaux , Sites de fixation , Calcium/métabolisme , Canaux calciques/isolement et purification , Membrane cellulaire/métabolisme , Entamoeba histolytica/composition chimique , Inositol 1,4,5-trisphosphate/métabolisme , Récepteurs à l'inositol 1,4,5-triphosphate , Inositol phosphates/métabolisme , Masse moléculaire , Sous-unités de protéines , Protéolipides/métabolisme , Récepteurs cytoplasmiques et nucléaires/isolement et purificationRésumé
In two successive experiments detection of sialic acid was achieved from trophozoites of axenically grown E. histolytica (NIH:200) using silicic acid column chromatography for the separation of sialosylated lipids and asialosylated lipids from total lipids. Sialic acid of the sialosylated lipids was detected through thiobarbituric acid assay followed by acid hydrolysis. These findings indicate that presence of sialic acid is not only a character of the cystic stage but also that of trophozoites of E. histolytica. Detection of sialic acid confirmed the electronegative charge of the surface membrane (glycocalyx) of E. histolytica trophozoites.
Sujets)
Animaux , Chromatographie , Entamoeba histolytica/composition chimique , Humains , Acide N-acétyl-neuraminique , Acides sialiques/analyseRésumé
Fifty-two amoebic liver abscess cases were assessed for the release of lymphokines (LMIF) using detergent dissected membrane proteins (DDMP) of axenic Entamoeba histolytica (NIH:200) obtained with sodium deoxycholate treatment. Lymphokines release by T lymphocytes in response to both DDMP and whole amoebic lysate (WAL) was tested by leukocyte migration inhibition test on blood samples from amoebic liver abscess cases. A significant increase was noted in the release of LMIF and 100% positivity was observed with DDMP compared to whole amoebic extract with a positivity of 73%. The difference between means of the above two with regards to release of LMIF was found to be highly significant (P less than 0.005). This shows the patients had high degree of leukocyte sensitization to surface antigens of E. histolytica compared to the whole amoebic lysate. These findings suggest that the antigens shed might have important role as a potent antigen in elicitation of CMI response in amoebic liver abscess cases.