Editors' Choice

Science  07 Jan 2011:
Vol. 331, Issue 6013, pp. 11
  1. Plant Science

    Boosting Biofuels

    1. Pamela J. Hines
    CREDIT: SCOTT MCNEIL

    The cell walls of plant stems that are stiffened by lignocellulose not only support an upright growth habit but are also coincidentally used as the starting materials for biofuel production. Studying Arabidopsis and Medicago, Wang et al. now show that WRKY transcription factors control the stiffening of cell walls in some tissues. The authors identified mutations in Medicago that resulted in plants with increased lignin content. Related genes were identified in Arabidopsis and poplar. In Arabidopsis, cells in the central pith of the stem normally have thin cell walls. Cells in the next layer out have thicker cells walls filled with lignin and cellulose. Deletion of WRKY transcription factors resulted in pith cells whose cell walls are thickened with lignin and cellulose; the resulting plants deliver more biomass per plant. Cell walls in other layers of the stem were unaffected, and overall growth of the plant appeared normal. Such insights into the molecular regulation of lignocellulose formation point to a possible way to increase biomass yield for biofuel production.

    Proc. Natl. Acad. Sci. U.S.A. 107, 22338 (2010).

  2. Microbiology

    A Boring Life

    1. Nicholas S. Wigginton

    In the deep oceans, carbonate minerals precipitate slowly, forming the building blocks of limestone or the shells of many marine organisms. Some filamentous bacteria, including photosynthetic autotrophs, can bore deep into these carbonates, but this biological mining process remains a paradox; photosynthesis usually causes carbonates to grow, not dissolve. Garcia-Pichel et al. showed how one type of cyanobacteria—originally isolated from a marine snail shell—was able to bore into chips of calcite (CaCO3) in laboratory experiments by controlling the saturation state of calcium. A number of tests, including enzyme-inhibition assays and fluorescence microscopy, suggest that these bacteria used a calcium-ion pump to transport calcium from the boring front, through the cell, and then back out toward the top of the bore hole. Furthermore, based on experiments in both light and dark conditions, boring was probably not directly related to photosynthetic activity. If this mechanism is widespread in other marine carbonates, inhibiting calcium-ion pumps in some cyanobacteria could slow the destructive dissolution of coral reefs and shellfish.

    Proc. Natl. Acad. Sci. U.S.A. 107, 21749 (2010).

  3. Science Policy

    Electrifying Success?

    1. Brad Wible

    Concept House, site of the UK Intellectual Property Office.

    CREDIT: INTELLECTUAL PROPERTY OFFICE

    Liberalization of the UK electricity sector beginning in the 1990s restructured the market by privatizing assets and reforming regulations. The goal was to improve the efficiency of the industry by increasing competition. Jamasb and Pollitt have now analyzed the impact on UK patenting activity and R&D investment in the electricity sector. They noted that whereas government R&D investment had already been declining, this trend was amplified after liberalization, although some increase has been seen in recent years, particularly in renewable energy. Private R&D also diminished after liberalization. Patenting activity, a marker of technology innovation, initially increased, probably reflecting increased emphasis on commercialization of R&D in the electricity industry. In recent years, though, UK patenting has slowed, which the authors attribute to decreased investment in basic R&D and increased foreign ownership of large utilities, which may lead to the transfer of R&D efforts out of the United Kingdom. They highlight efforts such as the Energy Technologies Institute and Innovation Funding Incentive, which aim to integrate public investment and market incentives to promote long-term R&D needed to ensure industry innovation.

    Res. Policy 10.1016/j.respol.2010.10.010 (2010).

  4. Chemistry

    Hothouse Catalysis

    1. Gilbert Chin

    Although some have said that physical organic chemistry is a field whose time has passed, it still is possible, with a bit of creativity, to extract provocative ideas from the growing compendium of chemical data collected on those most interesting of catalysts, enzymes. Stockbridge et al. begin with Arrhenius plots, which relate the logarithm of the rate constant to the reciprocal of temperature. They use these to estimate the rates of reaction of a variety of conversions, such as the hydrolysis of peptide bonds and of phosphate monoesters, and find large enhancements as the temperature increases from the common laboratory setting of 25°C to the primordial environment of 100°C, which turn out to be 3000-fold for the former and 107-fold for the latter. Why should we care? Because the rates of the slowest reactions increase the most, and thus the synthesis and transformation of small organic molecules would have flourished at 100°C. Enzymes, which make these reactions go fast enough at 25°C to sustain life today, would have been highly sought after as the ambient conditions cooled. Furthermore, lowering enthalpic barriers, as most enzymes do, is a more effective catalytic strategy than boosting entropy as temperatures drop.

    Proc. Natl. Acad. Sci. U.S.A. 107, 22102 (2010).