In PLoS One this week, a trio of researchers at the University of Oregon show that in Caenorhabditis elegans "compensatory mutations can be more frequent under high mutation rates and may alleviate a portion of the fitness lost due to the accumulation of deleterious mutations." To determine the ability of self-fertilizing nematode populations to "purge deleterious mutations at multiple loci," the Oregon team exposed C. elegans to a range of elevated mutation rates. Beyond mutation accumulation and a reduction in mean fitness, the team "also found that obligate and predominantly self-fertilizing populations exposed to very high mutation rates exhibited consistently greater fitness than those subject to lesser increases in mutation rate."
Researchers at Israel's Weizmann Institute of Science and the Hebrew University of Jerusalem describe a next-generation re-sequencing-based mutation detection approach, which "utilizes the genome of relative organisms as mediators for comparing [wild-type] and mutant bacteria." More specifically, by sequencing both the mutant and wild-type genomes and mapping the resulting short reads to the mediator genome, the researchers were able to detect the differences between them. The team validated its approach by sequencing Bdellovibrio bacteriovorus 109J and its prey-independent mutant.
In another PLoS One paper, investigators at Denmark's Statens Serum Institut describe Amp-PCR, an approach that combines "a random unbiased Phi29-amplification with a specific real-time PCR, performed in one tube, to increase PCR sensitivity." In Amp-PCR, the authors write, the "two reactions are separated physically by a wax layer ... and are run in sequel." The team suggests that its approach makes it "possible to detect positive samples normally under the detection limit of the specific real-time PCR," and reduces the risk of contamination.
Researchers in the UK and China present an mRNA-based approach to activate pluripotency genes in human fibroblasts. By transfecting synthetic mRNAs encoding OCT4, SOX2, cMYC, KLF4, and SV40 large T into human fibroblasts, the team found that the cells "expressed these factors at levels comparable to, or higher than, those in human embryonic stem cells." The authors suggest that their method can be useful for controlling protein expression levels in these calls and also for the "short-term expression of reprogramming factors."