Rapid DNA extraction methods and new primers for randomly amplified polymorphic DNA analysis of Giardia duodenalis

A randomly amplified polymorphic DNA (RAPD) procedure using simple genomic DNA preparation methods and newly designed primers was optimized for analyz ing Giardia duodenalis strains. Genomic DNA was extracted from in vitro cul tivated trophozoites by five freezing-thawing cycles or by sonic treatment. Compared to a conventional method involving proteinase K digestion and phe nol extraction, both freezing-thawing and sonication were equally efficient , yet with the advantage of being much less time- and labor-intensive. Five of the 10 tested RAPD primers produced reproducible polymorphisms among fi ve human origin G. duodenalis strains, and grouping of these strains based on RAPD profiles was in agreement among these primers. The consistent class ification of two standard laboratory reference strains, Portland-1 and WB, in the same group confirmed previous results using other fingerprinting met hods, indicating that the reported simple DNA extraction methods and the se lected primers are useful in RAPD for molecular characterization of G. duod enalis strains. (C) 1999 Elsevier Science B.V. All rights reserved.