Editors' Choice

Science  01 Dec 2017:
Vol. 358, Issue 6367, pp. 1144
  1. Plant Ecology

    Coping with invasion and warming

    1. Andrew M. Sugden

    Invasive Rudbeckia triloba is less affected by climate warming than native European species.

    PHOTO: CLARE GAINEY/ALAMY STOCK PHOTO

    Native plant communities worldwide face the challenges of anthropogenic changes, among them climate warming and invasion by introduced species. Haeuser et al. investigated the synergy between these two processes in a field experiment in native grassland in Germany. They sowed seeds of introduced ornamental plants together with those of the native grassland flora and compared the colonization and establishment of the two groups in artificially warmed plots and control plots. Although most species in both groups showed decreased performance under warming, the ornamentals were less severely affected. Hence, climate warming may increase the relative success of invasive species in such systems.

    J. Ecol. 105, 1698 (2017).

  2. Enzymes

    An enzymatic route to alkenes

    1. Michael A. Funk

    Conversion of fatty acids to fully deoxygenated hydrocarbons is a challenging reaction for which few biological routes are known. Christenson et al. have characterized a bacterial enzyme, OleB, that catalyzes decarboxylation of fatty acid-derived β-lactones to form cis-olefins. OleB is a member of an enzyme family that typically uses a nucleophilic carboxylate in hydrolysis reactions. Sequence analysis and biochemical assays suggest that the conserved catalytic residues have been adapted to facilitate excision of the β-lactone. This group of enzymes may prove to be useful for biofuel production if their substrate range and efficiency can be tuned through engineering.

    Biochemistry 56, 5278 (2017).

  3. Quantum Gases

    Putting an old law to the test

    1. Jelena Stajic

    Most superfluids, liquids, and gases that flow without viscosity owe their exotic properties to Bose-Einstein condensation (BEC), the formation of a macroscopic wave function at low temperatures. However, not all particles in a superfluid condense; a fundamental limit is set by the interactions in the system. Lopes et al. studied the dependence of the superfluid fraction in a homogeneous BEC of potassium atoms on the (tunable) strength of interactions between them. The researchers used two laser beams to give a momentum “kick” only to the condensed atoms, causing them to physically separate from the uncondensed ones. The measured fraction closely followed the theoretical prediction made decades ago that had remained experimentally untested.

    Phys. Rev. Lett. 119, 190404 (2017).

  4. Protein Design

    Designed to stand the heat

    1. Valda Vinson

    Enzymes are valued as catalysts in the synthesis of pharmaceuticals, fine chemicals, and biofuels. A limitation is that most enzymes are unstable under the reaction conditions used in chemical manufacturing. Moore et al. describe a strategy for stabilization based on designing covalent protein staples into an enzyme scaffold. They used Rosetta design software to identify optimal sites for introducing thioether bonds between a cysteine residue and a noncanonical amino acid. The design was implemented in an enzyme used in the biosynthesis of drugs containing cyclopropane. Several rounds of optimization yielded an enzyme containing two staples with enhanced thermal stability and resistance to chemical denaturation and organic solvents. The modified enzyme showed no reduction in activity or selectivity relative to the parent enzyme.

    Proc. Natl. Acad. Sci. U.S.A. 10.1073/pnas.1708907114 (2017).

  5. Gravitational Lensing

    Seeing microlensing from multiple angles

    1. Keith T. Smith

    The Spitzer Space Telescope helped characterize gravitational microlensing of a brown dwarf star.

    ILLUSTRATION; NASA/JPL-CALTECH/R. HURT (SSC)

    General relativity shows that massive objects deflect light. If a background star and a moving foreground object line up with Earth, the system acts as a lens that appears to temporarily increase the brightness of the star, an effect known as gravitational microlensing. Zhu et al. observed a microlensing event simultaneously with the Kepler and Spitzer space telescopes, as well as from Earth. Because the two spacecraft and Earth have widely separated orbits, the same event was effectively viewed from three different angles. This allowed the determination of key physical parameters that would otherwise have multiple solutions, which showed that this event was caused by a brown dwarf in the bulge of our Milky Way Galaxy.

    Astrophys. J. 849, L31 (2017).

  6. Therapy

    Surviving heart attack inflammation

    1. Gemma Alderton

    Heart attack (myocardial infarction) causes cell death and inflammation of cardiac tissue. It is not yet clear what mechanisms specifically cause fatality. King et al. show that ischemia (restricted blood flow to the heart muscles) caused by infarction results in cell death. Debris from the dead cells is taken up by macrophages (a type of immune cell). This results in an interferon regulatory factor 3 (IRF3) and type I interferon (IFN) inflammatory response, which activates a distinct population of cardiac macrophages. Mice deficient in IRF3 and type I IFN signaling showed improved survival after myocardial infarction. Moreover, treatment of mice with neutralizing antibodies to the type I IFN receptor after myocardial infarction improved their survival, indicating that this might be an avenue for treatment.

    Nat. Med. 10.1038/nm.4428 (2017).

  7. Aging

    Signaling an extended health span

    1. L. Bryan Ray

    Research on aging increasingly emphasizes the importance of health span rather than life span itself. Yin et al. found that in the nematode worm Caenorhabditis elegans, genetic variation in some (but not all) measures of health span was influenced by variation in genes encoding a neuropeptide and its corresponding receptor. The peptide is made in glial cells and activates a receptor on neurons that is similar to the somatostatin and nociceptin receptors of mammals. Loss of signaling in this pathway extended virility and digestive tract function. Understanding such mechanisms might allow therapies that promote health span—a very welcome possibility in a world faced with an expanding population of elderly individuals.

    Nature 10.1038/nature24463 (2017).

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