Editors' Choice

Science  27 Mar 2015:
Vol. 347, Issue 6229, pp. 1433
  1. Cell Regeneration

    Weaning means more than no more milk

    1. Beverly A. Purnell

    Weaning enhances the regenerative potential of pancreatic beta cells


    Nursing mothers provide much needed nutrition to offspring, but the full effects of weaning on offspring's physiology is unknown. Stolovich-Rain et al. now show that in mice, weaning affects the function of insulin-producing beta cells in the pancreas. The ability of beta cells to regenerate after injury or to modulate their insulin secretion decreases with age. However, beta cells also regenerated poorly in response to injury in very young mice and only gained this function upon weaning. These results suggest that at least for mouse beta cells, weaning jump-starts the cell cycle and modulates insulin production in response to glucose.

    Curr. Biol. 24, 2733 (2014).

  2. Cancer Biology

    A CRISPR view of tumor metastasis

    1. Paula A. Kiberstis

    Large tumors metastasize more often than small tumors. Is this simply because large tumors release a greater number of malignant cells into the circulation? Or is it because the genetic changes in tumor cells that drive them to proliferate rapidly are the same as those that promote their metastatic behavior? To explore this question, Chen et al. designed a screen based on a genome-editing technology called CRISPR-Cas9 to identify genes that, when inactivated, enhance tumor growth, lung metastasis, or both in mice. The small set of inactivated genes found in metastatic lesions largely overlapped with the set found in late-stage primary tumors, implying that functional loss of these genes drives both growth and metastasis.

    Cell 10.1016/j.cell.2015.02.038 (2015).

  3. Cell Biology

    Fatty acid trafficking in starvation

    1. Monika S. Magon

    Starving cells switch their metabolism from glucose-based to mitochondrial oxidation of fatty acids (FAs). This requires FAs to move from lipid droplets, their home during times of ample nutrition, to the mitochondria. Because free FAs in the cytoplasm are toxic to cells, cells stringently control their trafficking and metabolism. To better understand how cells coordinate these processes during starvation, Rambold et al. tracked fluorescently labeled FAs in live mouse cells. Enzymes called lipases freed FAs from lipid droplets, allowing their transfer to highly fused mitochondria located nearby. Autophagy, an intracellular degradation process, replenished FAs to lipid droplets. Such careful coordination allows cells to generate substrates for mitochondrial energy production while preventing free FAs-related toxicity.

    Dev. Cell 10.1016/j.devcel.2015.01.029 (2015).

  4. Conservation

    The hazards of isolation

    1. Sacha Vignieri

    Climate change threatens lemurs in Madagascar.


    Climate change affects animals in many ways, including shrinking and shifting their range. On continents, shifts may facilitate adaptation, but many highly threatened species live in regions where geography limits how far their range can shift. One region facing this challenge is Madagascar, where most species are endemic. Brown and Yoder used a suite of spatial modeling approaches to predict how warming might affect Madagascar's iconic lemur species. They found that 60% of lemur species face range contractions due to climate change. They highlight regions of highest conservation concern and conclude that long-term persistence of lemurs will require maintaining dispersal corridors and reducing habitat loss.

    Curr. Biol. 24, 2733 (2014).

  5. Organic Chemistry

    Ionic liquids can ring in carbon dioxide

    1. Jake Yeston

    The growing risks of atmospheric carbon dioxide (CO2) emissions are prompting chemists to explore more productive uses for the gas. Hu et al. present a simple means of coaxing carbon dioxide into small, ring-shaped molecules called oxazolidinones, which are of interest in medicinal chemistry research. Specifically, they found that certain ionic liquids can act as both solvent and catalyst to couple CO2 with propargylic amines. This environmentally benign approach avoids the need to add metals to accelerate the reaction. The solvent showed consistent performance over five cycles of recovery and reuse.

    Angew. Chem. Int. Ed. 10.1002/anie.201411969 (2015).

  6. Materials Science

    Something fishy about synthetic armor

    1. Marc S. Lavine

    Fish scales inspire flexible armor


    Many fish are covered in rigid scales attached to a flexible dermis layer, an arrangement that is compliant, resistant to penetration, and lightweight—in other words, an efficient coat of armor. Fink et al. use this as inspiration for a synthetic protective material based on a stretchable mesh that supports a set of hard plastic tiles. The mesh, made from periodically repeating, sinusoidal polypropylene fibers, provides in-plane elasticity and holds the scales, made from cellulose acetate butyrate, in place as the material is deformed. It also provides a mechanism for scales to rotate and interact with adjacent scales. The mechanical response during in-plane deformation, flexure, and indentation showed many of the advantageous attributes of its biological counterpart.

    ACS Appl. Mater. Interfaces 10.1021/acsami.5b00258 (2015).

  7. Education

    A CURE for promoting undergraduate research

    1. Melissa McCartney

    In a perfect world, all undergraduate students would participate in a Course-based Undergraduate Research Experience (CURE). Students participating in CUREs report gains similar to those of students participating in research internships, promoting CUREs as a scalable alternative. What, exactly, do we know about the causal mechanisms underlying the efficacy of CUREs? Using a systems approach, Corwin et al. reviewed literature on CUREs and research internships, generated a comprehensive set of outcomes, and connected these outcomes to what students actually do while enrolled in a CURE. These individual outcome models were then combined into an overarching model depicting the relationships among student activities and outcomes. These models are presented with the hope that the CURE community will test and revise them.

    CBE Life Sci. Educ. 10.1187/cbe.14-10-0167 (2014).