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Comparison of magnetic bead and rapid swab RNA extraction methods for detecting rabbit hemorrhagic disease virus 2 in rabbit liver samples

We compared a bead RNA extraction method with a one-tube method that required only a heat block and ice. RNA was first extracted from liver samples from nine rabbits dying from rabbit hemorrhagic disease virus 2 (RHDV2) using magnetic beads, and RT-PCR was used to detect RHDV2 sequence. Following freezing, RNA was extracted a second time using the SwiftX™ Swabs Viral RNA Extraction Reagent. RHDV2 was detected in all nine samples. Cycle threshold values were higher in the RT-PCR following SwiftX extraction (mean: 3.79), indicating that the second extraction method resulted in approximately a 1 log 10 reduction in sensitivity. A second freeze–thaw for the samples and less tissue extracted using SwiftX may have contributed additionally to the loss in sensitivity.

BioTechniques

Considerations for colorblind individuals on selecting colorimetric or fluorescent dye assay outcomes

A disadvantage of colorimetric detection in nucleic acid amplification assays is the possibility that a colorblind individual may interpret colors differently than observers with full-color vision. Using an isothermal amplification assay, the ability of colorblind individuals to distinguish between positive and negative results for four dyes was tested. Five individuals with self-reported colorblindness and four with full-color vision reported their observations of the color of the solution. Although colorblind individuals may accurately interpret assay results, they were often not accurate in reporting the color. Hydroxynaphthol blue was the most problematic dye, and both phenol red and SYBR™ green were less troublesome. Consideration for colorblind individuals is warranted when developing an assay and training staff in its performance.

BioTechniques