title: An Entamoeba sp. strain isolated from rhesus monkey is virulent but genetically different from Entamoeba histolytica.
abstract: An Entamoeba sp. strain, P19-061405, was isolated from a rhesus monkey in Nepal and characterized genetically. The strain was initially identified as Entamoeba histolytica using PCR amplification of peroxiredoxin genes. However, sequence analysis of the 18S rRNA gene showed a 0.8% difference when compared to the reference E. histolytica HM-1:IMSS human strain. Differences were also observed in the 5.8S rRNA gene and the internal transcribed spacer (ITS) regions 1 and 2, and analysis of the serine-rich protein gene from the monkey strain showed unique codon usages compared to E. histolytica isolated from humans. The amino acid sequences of two hexokinases and two glucose phosphate isomerases also differed from those of E. histolytica. Isoenzyme analyses of these enzymes in the monkey strain showed different electrophoretic mobility patterns compared with E. histolytica isolates. Analysis of peroxiredoxin genes indicated the presence of at least seven different types of protein, none of which were identical to proteins in E. histolytica. When the trophozoites from the monkey strain were inoculated into the livers of hamsters, formation of amebic abscesses was observed 7 days after the injection. These results demonstrate that the strain is genetically different from E. histolytica and is virulent. Revival of the name Entamoeba nuttalli is proposed for the organism.
authors.affiliation: Department of Infectious Diseases, Tokai University School of Medicine, Isehara, Kanagawa 259-1193, Japan. htachiba@is.icc.u-tokai.ac.jp
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tachibana
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Yanagi
authors.forename: Kishor
authors.initials: K
authors.lastname: Pandey
authors.forename: Xun-Jia
authors.initials: XJ
authors.lastname: Cheng
authors.forename: Seiki
authors.initials: S
authors.lastname: Kobayashi
authors.forename: Jeevan B
authors.initials: JB
authors.lastname: Sherchand
authors.forename: Hiroji
authors.initials: H
authors.lastname: Kanbara
mesh_terms: D000818:Animals; D001483:Base Sequence; D006224:Cricetinae; D016054:DNA, Protozoan / Q000032:analysis; D004275:DNA, Ribosomal / Q000032:analysis; D004747:Entamoeba / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity*; D004748:Entamoeba histolytica / Q000145:classification* / Q000235:genetics; D004749:Entamoebiasis / Q000469:parasitology / Q000662:veterinary*; D006801:Humans; D008099:Liver / Q000469:parasitology / Q000473:pathology; D008253:Macaca mulatta / Q000469:parasitology*; D008297:Male; D008647:Mesocricetus; D008969:Molecular Sequence Data; D008992:Monkey Diseases / Q000469:parasitology*; D012337:RNA, Ribosomal, 18S; D014774:Virulence
chemical_list: D016054:DNA, Protozoan; D004275:DNA, Ribosomal; D012337:RNA, Ribosomal, 18S