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This Week in PNAS: Dec 9, 2014

Editor's Note: Some of the articles described below are not yet available at the PNAS site, but they are scheduled to be posted some time this week.

In the early, online edition of the Proceedings of the National Academy of Sciences, researchers from the University of Michigan and the University of Maryland describe fitness genes turned in uropathogenic Escherichia coli — a form of E. coli implicated in urinary tract infections — as it infects its host. The team used RNA sequencing to profile transcriptional patterns in uropathogenic E. coli found in urine samples from individuals with acute, uncomplicated UTIs. Among the genes up-regulated in the bug's transcriptional signature were ion transport-coding genes suspected of bolstering its survival during human infection.

A team from Russia, the UK, and the US used scoured enzyme coding genes in more than a dozen plant genomes to begin tallying up the diversity found in a group of plant natural products known as terpenes. Based on terpenoid synthase and cytochrome P450 gene repertoires in nine eudicot plan genomes, four monocot plant genomes, and a handful of additional dicot and monocot scaffold sequences, the researchers saw slight genomic organization of the terpene metabolism coding components in the eudicot and monocot plant groups. "Our analyses shed light on the roots of terpene biosynthesis and diversification in plants," the study's authors say. "They also reveal that different genomic mechanisms of pathway assembly predominate in eudicots and monocots."

Finally, New Zealand researchers report on an optogenetic system that they developed for studying populations of neurons known as gonadotropin-releasing hormone neurons, which are distributed in small clusters throughout the mammalian brain and contribute to hormone pulses involved in reproduction and other functions. The method involved transfecting such neurons with light-activated channelrhodopsin proteins in mice, they say, producing a system that selectively activates the neurons of interest of stretches of between 30 seconds and five minutes.

The Scan

Positive Framing of Genetic Studies Can Spark Mistrust Among Underrepresented Groups

Researchers in Human Genetics and Genomics Advances report that how researchers describe genomic studies may alienate potential participants.

Small Study of Gene Editing to Treat Sickle Cell Disease

In a Novartis-sponsored study in the New England Journal of Medicine, researchers found that a CRISPR-Cas9-based treatment targeting promoters of genes encoding fetal hemoglobin could reduce disease symptoms.

Gut Microbiome Changes Appear in Infants Before They Develop Eczema, Study Finds

Researchers report in mSystems that infants experienced an enrichment in Clostridium sensu stricto 1 and Finegoldia and a depletion of Bacteroides before developing eczema.

Acute Myeloid Leukemia Treatment Specificity Enhanced With Stem Cell Editing

A study in Nature suggests epitope editing in donor stem cells prior to bone marrow transplants can stave off toxicity when targeting acute myeloid leukemia with immunotherapy.