Science  19 Jul 2013:
Vol. 341, Issue 6143, pp. 221

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  1. Cancer Knife Sniffs Out Tumor Cells


    When cancer surgeons can't see the edges of a tumor, they often send some tissue to the pathology lab, which can take up to 30 minutes per analysis. Now, there's an alternative: The "intelligent knife," or iKnife. When tissue is seared by a standard electrosurgical scalpel, the iKnife sucks the resulting smoke into a modified mass spectrometry machine. The instrument aims to instantly detect whether cells are cancerous or healthy by analyzing this smoke for certain lipids, or fats, and comparing this profile to molecular signatures for various cancer types. When tested during 81 surgeries, the iKnife matched pathology results for cancerous and normal tissues for every single patient, the researchers report this week in Science Translational Medicine.

    The iKnife provides "real-time information," says its inventor Zoltán Takáts, a Hungarian chemist who collaborated with biochemist Jeremy Nicholson at Imperial College London to develop the tool. Their next step is to conduct clinical trials to find out if using the iKnife helps patients develop fewer recurring tumors and live longer.

  2. Shedding Light on Microbial 'Dark Matter'

    Mysteries revealed.

    Now microbes from environmental samples can be characterized from their genomes.


    When researchers began sequencing DNA from environmental samples more than a decade ago, they discovered a vast, diverse world of microbes. But this microbial dark matter has defied further description—and definitive placement on the tree of life—because so few kinds will grow in the lab.

    That didn't stop microbiologist Tanja Woyke from the Department of Energy Joint Genome Institute in Walnut Creek, California. She and her colleagues used an approach that allowed them to sequence the DNA in individual cells (rather than requiring many copies of the cells). They characterized 200 new microbes from 29 largely uncharted phyla, then used the genomes to determine the microbes' phylogenetic relationships and to assess how each lives, naming 18 phyla accordingly, the team reported online this week in Nature. Novelties emerged: Some archaea possess genes previously thought to exist only in bacteria; some bacteria have archaeal genes. One group of microbes has even altered the three-base coding system for proteins.

    In the future, single-cell sequencing could fill in more branches of the microbial tree of life. "It's an inflection point in environmental microbiology and microbiology in general," says Norman Pace, a microbiologist at the University of Colorado, Boulder.