In this week's Early Edition, the University of Geneva's Béatrice Lecroq et al. report their sequencing of 31 unsieved deep-sea sediment samples from five distinct oceanic regions to assess foraminiferal richness. Of the 495,978 unique sequences obtained and grouped into 1,643 operational taxonomic units, "of which about half (841) could be reliably assigned to foraminifera," the team found evidence contrary to the "classical view of multi-chambered taxa dominating foraminiferal assemblages." Overall, the researchers say that their work "reflects an unexpected diversity of monothalamous lineages that are as yet unknown using conventional micro-paleontological observations."
Elsewhere in PNAS, the University of Wisconsin's Dana Wohlbach et al. report their sequencing of two xylose-fermenting, beetle-associated fungi — Spathaspora passalidarum and Candida tenuis. Then, using a comparative genomic approach across 14 Ascomycete genomes, the team identified many genes implicated in xylose assimilation processes. "Several of these genes significantly improved xylose utilization when engineered into S. cerevisiae, demonstrating the power of comparative methods in rapidly identifying genes for biomass conversion while reflecting on fungal ecology," the authors write.
Researchers at the University of Nevada School of Medicine this week show that murine spermatogenic cells express many endogenous siRNAs, which they say "are likely to be derived from naturally occurring double-stranded RNA precursors." Further, the Nevada team shows that these endo-siRNAs "can potentially target hundreds of transcripts or thousands of DNA regions in the genome."
Yale University School of Medicine's Qin Yan and his colleagues have found that "loss of the retinoblastoma binding protein 2 (RBP2) histone demethylase suppresses tumorigenesis in mice lacking Rb1 or Men1." More specifically, Yan et al. observed that "genetic ablation of Rbp2 decreases tumor formation and prolongs survival in Rbl +/- mice and Men1-defective mice."