title: Evidence for selection of virulent sub-populations of Entamoeba histolytica by cholesterol.
abstract: Quantitatively much higher Concanavalin A (Con. A) agglutinability, haemolytic potency, and activities of acid hydrolases, namely phosphatase (EC 3.1.3.2), ribonuclease (EC 2.7.7.16), deoxyribonuclease (EC 3.1.4.5) and proteinase--were observed in a virulent strain of Entamoeba histolytica (IP-106), as compared to attenuated and avirulent strains (200-NIH) and DKB respectively. In addition, significant differences in these parameters were observed among clonal cultures derived from the latter two cultures by cultivation of single amoebic cells picked out by micromanipulation. Repeated sub-culturing of parent cultures of both these strains in cholesterol-enriched medium resulted in marked enhancement of all the above activities, but no such change occurred in the derived clonal cultures following similar cholesterol treatment. The implication of these findings in relation to enhancement of the virulence of E. histolytica by cholesterol is discussed.
authors.affiliation: Division of Microbiology, Central Drug Research Institute, Lucknow, India.
authors.forename: S K
authors.initials: SK
authors.lastname: Katiyar
authors.forename: S
authors.initials: S
authors.lastname: Ghoshal
authors.forename: S R
authors.initials: SR
authors.lastname: Das
authors.forename: V C
authors.initials: VC
authors.lastname: Panday
authors.forename: P
authors.initials: P
authors.lastname: Sagar
mesh_terms: D000135:Acid Phosphatase / Q000378:metabolism; D000371:Agglutination; D000818:Animals; D002784:Cholesterol / Q000494:pharmacology*; D003208:Concanavalin A; D003470:Culture Media; D003851:Deoxyribonucleases / Q000378:metabolism; D010450:Endopeptidases / Q000378:metabolism; D004748:Entamoeba histolytica / Q000201:enzymology / Q000378:metabolism / Q000472:pathogenicity*; D006461:Hemolysis; D012260:Ribonucleases / Q000378:metabolism; D014774:Virulence
chemical_list: D003470:Culture Media; D003208:Concanavalin A; D002784:Cholesterol; D003851:Deoxyribonucleases; D012260:Ribonucleases; D000135:Acid Phosphatase; D010450:Endopeptidases