ABSTRACT
Recombinant ribosomal DNA sequences were amplified by PCR and used as probes to perform a fingerprint analysis of total DNA from different Entamoeba histolytica isolates. RFLPs obtained with one of the probes, R-1, support previous proposals that pathogenic and non-pathogenic E. histolytica are closely related, yet genotypically distinct. Another probe, R-2, while not distinguishing between the two forms of E. hystolytica, was able to differentiate between them and E. moshkovskii, which has morphologically identical cysts and trophozoites. A third probe, BR-1, identified strain-specific RFLPs.
Subject(s)
DNA Fingerprinting , DNA Probes , DNA, Protozoan/analysis , DNA, Ribosomal , Entamoeba histolytica/genetics , Animals , Blotting, Northern , Blotting, Southern , DNA, Protozoan/chemistry , DNA, Recombinant , Entamoeba histolytica/pathogenicity , Humans , Nucleic Acid Hybridization , RNA, Protozoan/analysis , RNA, Ribosomal/analysis , Repetitive Sequences, Nucleic Acid , Restriction MappingABSTRACT
A DNA sequence, IE-gen1 (3.1 kb), was isolated from the pathogenic strain of E. histolytica NIH-200. IE-gen1 was identified by the subtractive hybridization of a genomic library to a cDNA probe prepared from NIH-200 trophozoites. The IE-gen1 probe specifically detected pathogenic E. histolytica in slot blots of genomic DNA and Northern blots, but not other Entamoeba species and additional human parasites. This genomic probe could detect with complete specificity DNA from about 10(3) organisms. The IE-gen1 probe could be related to highly specialized loci in pathogenic E. histolytica, and is likely to be a valuable DNA reagent for clinical diagnosis and epidemiological investigations.
