title: Transcriptional upregulation of genes related to virulence activation in Entamoeba histolytica.
abstract: BACKGROUND
  To understand the molecular basis of virulence variability in Entamoeba histolytica, this study presents results about differential gene expression induced by E. histolytica trophozoites in liver of hamsters in order to produce experimental amebic liver abscess (ALA) and consequently reactivate its virulence.
  
  
  METHODS
  Amebic cultures were studied before (BALA) and after (AALA) inoculation in hamster peritoneal cavity. Markers of pathogenicity such as the rate of erythrophagocytosis, hemolytic activity, and cytotoxic effects on MDCK cell monolayers were evaluated in order to correlate these phenotypic characteristics to differential gene expression between virulent and non-virulent strains. Genotypic variability was determined by genetic polymorphism using the random-amplified polymorphic DNA (RAPD) technique, which defines the parasite genomic plasticity. mRNA differential display was used in order to identify variable transcripts levels.
  
  
  RESULTS
  The rate of erythrophagocytosis and hemolytic activity were notably increased in AALA in comparison with BALA E. histolytica cultures, as well as the cytotoxic effect on MDCK cells. An increment in the transcription level of several mRNA was shown.
  
  
  CONCLUSIONS
  The RAPD technique allowed us to confirm differences in number and size of polymorphic markers bands between virulent and non-virulent stages, suggesting genomic adaptability in E. histolytica. Eight different genes (membrane-bound acid phosphatase, cysteine proteinase, two different ribosomal proteins, heat shock transcription factor, ribosomal RNA, aldehyde dehydrogenase-1 and patatin-like phospholipase) were sequenced and may be associated with a biological function related to the virulence of E. histolytica. Together these findings show genomic variability between virulent and non-virulent cultures of E. histolytica.
authors.affiliation: Biotechnology Department, Facultad de Ciencias Químicas, Universidad Autónoma de Nuevo León, Monterrey Nuevo León, Mexico. ibalderas@hotmail.com
authors.forename: Isaias
authors.initials: I
authors.lastname: Balderas-Renteria
authors.forename: J Francisco
authors.initials: JF
authors.lastname: García-Lázaro
authors.forename: Pilar
authors.initials: P
authors.lastname: Carranza-Rosales
authors.forename: Lilia H
authors.initials: LH
authors.lastname: Morales-Ramos
authors.forename: Luis J
authors.initials: LJ
authors.lastname: Galan-Wong
authors.forename: Linda E
authors.initials: LE
authors.lastname: Muñoz-Espinosa
mesh_terms: D000818:Animals; D006224:Cricetinae; D004748:Entamoeba histolytica / Q000235:genetics* / Q000472:pathogenicity*; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D008099:Liver / Q000469:parasitology; D010641:Phenotype; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D053058:Trophozoites / Q000378:metabolism; D015854:Up-Regulation; D014774:Virulence / Q000235:genetics
chemical_list: D012333:RNA, Messenger