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Heterogeneity of the ribosomal DNA episome in strains and species of Entamoeba
Author(s) -
Cázares Febe,
ManningCela Rebecca,
Meza Isaura
Publication year - 1994
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.1994.tb01047.x
Subject(s) - biology , entamoeba , ribosomal dna , genetics , ribosomal rna , spacer dna , restriction fragment length polymorphism , dna , internal transcribed spacer , entamoeba histolytica , gene , phylogenetics , polymerase chain reaction
Summary Ribosomal DNA sequences in several species of the genus Entamoeba are highly repeated and display restriction fragment‐length polymorphism (RFLP), which has been used to identify species and differentiate strains. However, the continuous variability of the non‐transcribed repeat sequences in the ribosomal episome hinders an accurate typification. Looking for more reliable markers, we used DNA probes containing conserved sequences in the ribosomal episome — coding regions for the 16S and 5.8S rRNAs and transcribed spacers flanking the rDNA sequences, and the coding region for the 3 end of the 26S rRNA — to analyse hybridization patterns from five cloned pathogenic strains of Entamoeba histoiytica , two strains of the also pathogenic Entamoeba invadens and the non‐pathogenic Laredo strain of Entamoeba moshkovskii. Our results provide reliable bases for the differentation of clones, strains and species of Entamoeba and the reconstruction of E. histolytica episomes. Differences in the number and length of rDNA‐containing DNA fragments, previously observed by other investigators and confirmed by us, can be better defined by the present analysis.