Editors' Choice

Science  06 May 2016:
Vol. 352, Issue 6286, pp. 669
  1. Ecosystem Management

    Underappreciated benthos

    1. Sacha Vignieri

    Coastal fishes, such as this toadfish, depend on rocky and soft benthic habitats for reproduction and survival.

    PHOTO: TOM MCHUGH/SCIENCE SOURCE

    The management and monitoring of animal populations is shifting away from a model that focuses purely on abundance, to one that considers the importance of components of the physical and biological environment to a species' persistence. Kritzer et al. develop such an ecosystem management-based approach to evaluate a system whose contribution to healthy fish populations is underappreciated. They show that benthic habitats on the east coast of the United States are essential for fish reproduction, with the most valuable benthic forms varying latitudinally. Their analysis showed that some soft sediment habitats were much more important than expected, a notable result given that these habitats have typically been considered expendable.

    BioScience 10.1093/biosci/biw014 (2016).

  2. Diversity

    On-ramp to greater STEM diversity

    1. Melissa McCartney

    One path to achieving greater diversity in STEM (science, technology, engineering, and mathematics) fields is through “on-ramping,” the process by which women with Ph.D.'s leverage their nonacademic careers and enter academia as faculty members. Three On-Ramps into Academia workshops were held. Carrigan et al. used qualitative methods to analyze the experiences of 10 female Ph.D.'s who attended the workshop and successfully on-ramped into faculty positions. Four phases of on-ramping were identified, including evaluating the value of transferable nonacademic career skills, bridging gaps in experience, coping with both past and present gender discrimination, and affirming the value of producing scientific knowledge in academia. Results indicated that on-ramping women have much to bring to a faculty position, including bridging classroom learning to professional scenarios and connecting students to industry and government colleagues.

    J. Technol. Transf. 10.1007/s10961-015-9460-5 (2015).

  3. Metastasis

    Single file through capillaries

    1. Lisa D. Chong

    Tumor cell clusters break down to travel through tiny capillaries as single cells.

    PHOTO: S. H. AU ET AL., PNAS (26 FEBRUARY 2016) © 2016 NATIONAL ACADEMY OF SCIENCES

    Circulating tumor cell clusters (CTCs) are thought to be too large to pass through capillaries, yet such aggregates are found in the circulation, spreading cancer to distant sites. Au et al. used a microfluidic device to visualize how they accomplish this. CTCs (of 20 cells or more) isolated from human patient blood unfold into a chain of single cells to pass through microchannels that are the same width as human capillaries. Once through, the linked cells refold into a cluster. This behavior was also observed when human CTCs were transplanted into the circulation of transparent zebrafish. Determining how cells of a CTC break and reform their connections may lead to approaches that prevent their transit through capillaries and reduce metastasis.

    Proc. Natl. Acad. Sci. U.S.A., 10.1073/pnas1524448113 (2016).

  4. Antibiotic Resistance

    Resistance and sex among bacteria

    1. Caroline Ash

    Gene swapping among bacteria by conjugation (aka sex) has long been thought to be triggered by antibiotics, an effect which then promotes the spread of antibiotic-resistance genes. Lopatkin et al. tested a variety of antibiotics on conjugation and found that it is not so simple. Specifically, resistant offspring can be selected, but if the parents are already resistant, resistant offspring are not selected. Alternatively, if parent populations are killed, then less gene swapping occurs. Hence, the direction and efficiency of conjugation in the presence of antibiotics depends on the dynamics of the whole bacterial population. Models and sequencing can help distinguish and predict rates of gene swapping for particular conditions.

    Nat. Microbiol. 10.1038/nmicrobiol.2016.44 (2016).

  5. Neurodevelopment

    Myelination defects in Down syndrome

    1. Pamela J. Hines

    In Down syndrome (DS), an extra chromosome 21 causes a variety of developmental and cognitive disabilities. Olmos-Serrano et al., have compared the transcriptome of postmortem brains from normal donors as well as those with DS, surveying developmental stages from prenatal to adult. Of over 17,000 genes profiled from two regions of the brain, about 4% revealed abnormal expression. Dysregulated genes, found across the whole genome and throughout the age range, grouped by function. One group of genes affected oligodendrocytes and myelination. Indeed, myelination was deficient in a mouse model of DS, contributing to defective transmission of neural signals. The authors speculate that poor myelination may underlie the problems with learning, memory, and age-related neurodegeneration that characterize DS.

    Neuron 89, 1208–1222 (2016).

  6. Applied Physics

    Mind the (nano)gap

    1. Jake Yeston

    Modern pulsed lasers make it possible to time molecular processes that happen even faster than trillionths of a second. A pump pulse starts off the process, while an investigative probe pulse gets sent on a steadily lengthened detour to delay its arrival by precise increments. Unfortunately, the detour gets impractically long when phenomena last for several nanoseconds. Nakagawa et al. introduce a technique to bridge this coverage gap. Rather than setting a detour, they apply a train of probe pulses spanning a wide variety of delays (subnanosecond to millisecond) relative to the pump pulse. The full time frame is then filled in steadily shot by shot.

    Optics Lett. 41, 1498 (2016).

  7. Optomechanics

    Bouncing to higher sensitivity

    1. Ian S. Osborne

    Sensors capable of measuring tiny forces have applications in many fields of science and engineering. Such sensors typically exploit the change in the mechanical properties of materials in response to an applied force. Nanofabrication techniques can be used to make extremely sensitive membrane structures, the displacement and vibration of which can be used to sense forces; the highest sensitivity usually requires cooling the structures to cryogenic temperatures. Norte et al. and Reinhardt et al. now show that the mechanical properties of such membranes can be optimized to sense forces of just several tens of attonewtons (10−18 N) at ambient conditions. Their simplified trampoline-like structures, with the membranes suspended at just several connection points, opens up the devices to situations of real-life application.

    Phys. Rev. Lett. 116, 147202 (2016); Phys. Rev. X 6, 021001 (2016).