Science  20 Sep 2013:
Vol. 341, Issue 6152, pp. 1325

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  1. Wine Contaminant Puts a Cork in Olfactory Receptors


    Have you ever ordered a bottle of wine in a nice restaurant only to reluctantly send it back because the wine seemed "corked"—it had a musty odor and didn't taste quite right? There's a good chance that the wine was contaminated with 2,4,6-trichloroanisole (TCA), a molecule well known as the main cause of cork taint. A new study by Japanese researchers published online in the Proceedings of the National Academy of Sciences this week concludes that you don't actually smell TCA directly; rather, TCA blocks the action of olfactory cells in your nose, distorting your ability to detect odors. The findings, the result of experiments with extra-large newt olfactory cells and human wine tasting volunteers, could help the food and beverage industry improve its products and lead to less embarrassment for both you and your waiter.

  2. Full-Speed Reprogramming

    By removing a molecular brake, scientists can turn mature cells into embryolike ones with almost 100% efficiency. In a process called cellular reprogramming, researchers switch on four genes in skin, blood, or other mature cells to transform them into induced pluripotent stem cells (iPSCs), which can become any of the body's cell types. The procedure is usually hit-and-miss, though: The most efficient methods reprogram only around 10% of the mature cells into iPSCs.

    Now, Jacob Hanna and his colleagues at the Weizmann Institute of Science in Rehovot, Israel, have identified a protein that acts as a brake on the process. When the protein, called Mbd3, is removed by mutating its gene or interfering with its expression, the four reprogramming factors can turn nearly 100% of cells into iPSCs, Hanna and his colleagues report online in Nature this week. The reprogramming genes in fact recruit Mbd3 to the cell's chromosomes, where it inhibits their further expression. The find not only makes it easier to make iPSCs, it should also help researchers better understand how reprogramming works.

  3. Early Cichlids Traversed the World's Oceans


    More than 1600 species of cichlids swim in fresh water around the world, spanning a rainbow of colors and shapes. New research casts doubt on an old hypothesis: that cichlids reached multiple continents by swimming in place while the ancient super continent Gondwana broke up about 135 million years ago. The oldest known cichlid fossils are only about 45 million years old. To estimate just how likely it was that there are more ancient ones out there, paleobiologist Matt Friedman of the University of Oxford in the United Kingdom and colleagues compared a database of known cichlid fossils to a list of sedimentary rocks that might plausibly contain them and counted mutations in genes shared by cichlids and their relatives to estimate when they diverged. Their findings, published this week in the Proceedings of the Royal Society B, suggest a cichlid origin 65 million to 57 million years ago, long after Gondwana separated. The researchers say the little fish must have undertaken death-defying dispersals by paddling across the ocean.