The use of biomagnetic separation to recover DNA suitable for PCR from Claviceps species

Use of magnetic beads to extract fungal DNA

Authors compare two methods of extracting DNA from different fungi: the classic method with phenol/chloroform (P/C) and that with magnetic beads. Both were tested on Candida albicans and Cryptococcus neoformans var. neoformans, belonging to the yeast group and Microsporum canis, M. gypseum, Trichophyton rubrum, T. interdigitale, T. ajelloi, Epidermophyton floccosum, belonging to the dermatophytes group. Extraction products underwent polymerase chain reaction (PCR) fingerprinting with the appropriate primers to point out any disagreement in the genomic profiles. After having determined that the genomic profiles obtained from the DNA extracted from the same strain with the two methods correspond perfectly, the authors concluded that the extraction method with magnetic beads from fungal cells is simpler and quicker than with P/C extraction, greatly facilitating the obtainment of fungal DNA.

Rapid isolation of DNA from chocolate and date palm tree crops

DNA isolation from plants is sometimes difficult due to the existence of high levels of endogenous phenolics, polysaccharides, or other substances that may interfere with DNA extraction. Theobroma cacao produces high levels of anthocyanins in young leaves. These plant polyphenols can interfere with DNA isolation. After examination of various procedures for DNA isolation, two commercial isolation procedures have proved to be repeatedly successful using these types of plants, the D(2) BioTechnologies DNA X-tract Plus kit and the Qiagen DNeasy Plant System DNA kit. These commercial kits were chosen for their speed and ease over the CTAB procedure, which is more labor intensive. All protocols assessed yielded DNA suitable for AFLP or SSR procedures. An additional factor in DNA extraction efficiency is the degree of cell breakage, which may be more difficult with the highly fibrous leaf tissue that is found in many monocots, including date palm. Two commercially produced pieces of equipment were tested and, for cacao, both resulted in template DNA yielding amplification product in AFLP or SSR fingerprinting. However, for the fibrous date palm leaf, the larger FastPrep homogenizer consistently yielded DNA that generated higher signals when amplified than did the smaller Disruptor Genie.