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This Week in PNAS: Mar 6, 2018

Members of a University of Hong Kong-led team look at genetic diversity in Middle East respiratory syndrome coronavirus (MERS-CoV) isolates from dromedary camels in Africa. Using whole-genome sequencing, phylogenetic analyses, and phenotypic profiling, the researchers assessed a MERS-CoV isolate from Morocco, three from Burkina Faso, nine Nigerian MERS-CoVs, and three isolates from Ethiopia, initially in dromedary camel nasal swabs by RT-PCR. Comparing the viruses to one another and to previously analyzed isolates, they saw genetic and clinical variability in African MERS-CoV, including phylogenetic differences relative to strains from the Arabian Peninsula. "These finding highlight the need for extensive and sustainable surveillance and monitoring systems … to ascertain whether unrecognized zoonotic MERS infections are taking place," the authors conclude.

Researchers from India, the US, and Canada explore centromere evolution in Cryptococcus fungus representatives from the Basidiomycota phylum using chromatin immunoprecipitation sequencing (ChIP-seq). Starting with ChIP-seq experiments that targeted conserved inner kinetochore proteins, the team identified large regional centromeres rife with LTR retrotransposons in three pathogenic fungi profiled: C. neoformans, C. deneoformans, and C. deuterogattii. The centromeres appeared significantly shorter in the C. deuterogattii species, which was missing RNA interference machinery, prompting the authors to suggest that "RNAi, together with cytosine DNA methylation, serves as a critical determinant that maintains repetitive transposon-rich centromere structures."

Finally, a German team explores the feasibility of bolstering image-based tissue extraction that incorporates omic data — from nuclear magnetic resonance spectroscopy- or mass spectrometry-based metabolomic and proteomic measurements to transcriptomic or genomic sequencing. Using a cooled image-guided milling machine designed to ward off sample degradation, the researchers demonstrated the feasibility of doing metabolomic assessments, proteomic profiling, and more within a workflow for removing specific tissue or organ samples from small laboratory animals. "The plethora of information produced by these [omics] methods has proven to be valuable in the understanding of diseases such as cancer, neurodegenerative diseases, and many others," the authors write, adding that the "ability to link these procedures to imaging with high spatial accuracy will lead to a better understanding of the imaging data."