An international team led by investigators at Monash University in Melbourne reports in PLoS One this week its sequencing on a collection of isogenic, clinical, and laboratory Staphylococcus aureus strains, which — when combined with electron microscopy and lipid membrane studies on selected isolates — it used to characterize the genetic evolution of daptomycin resistance in the pathogen. "On average, six coding region mutations were observed across the genome in the clinical daptomycin exposed strains, whereas only two mutations on average were seen in the laboratory exposed pairs," the authors write, adding that "all daptomycin-nonsusceptible strains had a mutation in a phospholipid biosynthesis gene."
Researchers in France this week report on their metatranscriptomic investigation of cDNAs synthesized from polyadenylated mRNA directly extracted from soils sampled in beech and spruce forests, which, as they say in PLoS One, "reveals the diversity of genes expressed by eukaryotes in forest soils."
Elsewhere in the journal, investigators at National University of Ireland Maynooth and their colleagues argue in a quantitative evaluation of a DNA-barcoded cryptic bumblebee complex that "color patterns do not diagnose species." By assessing the value of color-pattern characters for species identification on barcoded queens from the Bombus lucorum complex, the team found "three distinct molecular operational taxonomic units," but "no uniquely diagnostic color-pattern character state … for any of these three molecular units and most color-pattern characters showed continuous variation among the units," it writes.
Over in PLoS Biology, MIT's Christopher Burge and his colleagues show that "alternative splicing of RNA triplets is often regulated and accelerates proteome evolution." More specifically, using RNA-seq data from 16 human and eight mouse tissues , Burge et al. found that "at least 25 [percent] of alternatively spliced NAGNAGs undergo tissue-specific regulation in mammals, and alternative splicing of strongly tissue-specific NAGNAGs was 10 times as likely to be conserved between species as was splicing of non-tissue-specific events, implying selective maintenance," they write.