Editors' Choice

Science  30 Sep 2016:
Vol. 353, Issue 6307, pp. 1510
  1. Evolution

    The importance of variation

    1. Sacha Vignieri

    Magellanic penguins in Punto Tombo, Argentina

    PHOTO: DON FAULKNER/FLICKR

    The environment exerts powerful selective forces on species, shaping their morphology. Despite this, individuals within a species can be quite variable, suggesting that selection may not always operate in expected ways. Koehn et al. measured selection in Magellanic penguins at Punta Tombo, Argentina, over nearly 30 years. Though this extreme environment would seem to impose powerful selective forces, they found evidence of selection at a suite of traits in only 7 of those years. When selection was detected, primarily for body size, it favored larger individuals. Such inconsistency in the strength and shape of selection over time likely maintains important variation within the population overall and suggests that there is no clear best-adapted morphology in this dynamic habitat.

    Auk 10.1642/AUK-16-50.1 (2016).

  2. Antimicrobial Resistance

    Beware of the dust

    1. Julia Fahrenkamp-Uppenbrink

    Antimicrobial chemicals are used in many soaps and other personal-care products. They are found in household dust at concentrations comparable to those in wastewater. Laboratory studies have shown that these chemicals can promote antimicrobial resistance in aqueous environments. Hartmann et al. explore whether they are also associated with antimicrobial resistance in indoor dust. They report a positive association between antimicrobial concentration and the abundance of multiple antibiotic-resistant genes in indoor dust at a mixed-use athletic and educational facility. Antimicrobials may thus have a strong influence on the promotion and retention of antibiotic-resistant genes in indoor environments.

    Environ. Sci. Technol. 10.1021/acs.est.6b00262 (2016).

  3. Cancer Therapy

    Drugging an undruggable target

    1. Paula A. Kiberstis

    Transcription factors have long been viewed as “undruggable” targets for therapy; however, this concept may now need some tweaking. Cho et al. found that a small-molecule drug (PT2399) that inhibits the activity of the transcription factor HIF2α (hypoxia-inducible factor 2α) has promising antitumor effects in mouse models of kidney cancer. HIF2α controls the expression of genes that help tumors cope with low amounts of oxygen. In mice, PT2399 suppressed the growth of metastatic kidney tumors and improved the animals' survival. Not all tumors responded to the drug, suggesting that in a clinical setting, doctors may need to rely on yet-to-be-discovered biomarkers to match the drug with the patients most likely to benefit.

    Nature 10.1038/nature19795 (2016).

  4. Vaccination

    Mapping the barriers to vaccination

    1. Caroline Ash

    Socioeconomic factors and attitudinal beliefs shape worldwide vaccination rates.

    PHOTO: JEROME DELAY/AP PHOTO

    Common infectious diseases are in decline thanks to increasing vaccination coverage, but this is a vulnerable triumph: UNICEF reports that nearly 22 million children remained unvaccinated in 2013. A study by de Figueiredo et al. shows two broad indicators at work: one, a suite of socioeconomic factors, and the other, attitudinal beliefs. Their vaccine performance index calls out the countries that are least likely, based on a series of indicators, to meet the Global Vaccine Action Plan target. These countries are largely in sub-Saharan Africa and Southeast Asia, where poor vaccination coverage correlates with a lack of access to water, health care, and education. Active refusal to vaccinate is more likely to occur in European countries.

    Lancet Global Health 4, e726 (2016).

  5. Hematopoiesis

    Transforming blood cell development

    1. Beverly A. Purnell

    Although the transplantation of hematopoietic stem cells (HSCs) enables many life-saving procedures, their limited availability prevents wider use. A better understanding of how they develop may assist in expanding the supply. During embryonic development, HSCs arise from a subset of endothelial cells in the dorsal aorta. Using zebrafish as a model, Monteiro et al. find that signaling pathways dependent on the protein TGFβ (transforming growth factor β) drive the endothelial-to-hematopoietic transition that leads to HSC development. First, TGFβ produced by the endothelial cells themselves programs the endothelium, and then its production by the notochord orchestrates the transition.

    Dev. Cell 38, 358 (2016).

  6. Interstellar Medium

    Reflected starlight traces dust structure

    1. Keith T. Smith

    The diffuse interstellar medium (ISM) is structured on many scales. Studies of gas absorption lines have shown that structure persists all the way down to solar-system scales, contrary to theoretical expectations, but it has been unclear whether the solid dust particles share this behavior. Miville-Deschenes et al. studied the cirrus-like pattern of starlight reflecting off of dust grains in a nearby region of the ISM. They find that the dust is structured with a single power law on all the scales that they can probe, a sign of turbulent motion within the ISM driven by galactic feedback processes.

    Astron. Astrophys. 593, A4 (2016).

  7. Chemical Physics

    Tracking triplets in pentacene polymers

    1. Jake Yeston

    Singlet fission is like a two-for-one sale in a solar cell: Light absorption populates a singlet state that splits into two triplet carriers. Key questions for efficient implementation of this phenomenon are how to optimize the formation of the triplets and then how to keep them apart afterward. Sanders et al. systematically studied singlet fission in oligomers and polymers of pentacene, a compound explored extensively for this purpose already as a monomer and dimer. They found that the fission rate gets faster as the pentacene chains get longer, though the consistently short lifetime of the triplet pair afterward is length-independent.

    Chem 1, 505 (2016).