Editors' Choice

Science  05 Jun 2020:
Vol. 368, Issue 6495, pp. 1077
  1. Materials Science

    Better food preservation

    1. Marc S. Lavine

    Postharvest spoilage of fresh fruits and vegetables is reduced by a safe and easily removed coating made with egg albumin.

    PHOTO: LILLY TROTT/SHUTTERSTOCK

    Fresh fruits and vegetables are a key part of a healthy diet but there can be considerable waste caused by spoilage after harvest. Shelf life can be extended by preventing microbial growth, dehydration, or storage at higher temperatures, but adding a wax coating, creating a reduced oxygen environment, or using refrigeration can be expensive and/or time consuming and may alter the taste of the food. Jung et al. developed an egg-sourced albumin coating reinforced with nanocrystalline cellulose that can be made from waste materials. When coated onto banana, avocado, papaya, and strawberry, shelf life was extended by a week, with reduced external browning and internal ripening. The coatings are safe to ingest but are also easily removed through washing.

    Adv. Mater. 10.1002/adma.201908291 (2020).

  2. Development

    Making cartilage throughout life

    1. Beverly A. Purnell

    The skeletons of newborn mammals are soft and pliable because they are composed primarily of cartilage. During growth to adulthood, most cartilage is replaced by bone. The remaining cartilage, such as that found in the joints, does not readily regenerate, so joints deteriorate with age. By contrast, elasmobranch fish make cartilage throughout their lives. Marconi et al. studied the cartilaginous fish Leucoraja erinacea, or little skate, from embryo to adult and observed that progenitor cells that surround the cartilage skeleton are also present in the adult. These cells are induced to transform into chondrocytes after injury. Understanding cartilage repair in skates may offer inspiration for research into human joint repair.

    eLife 9, e53414 (2020).

  3. Food Security

    Scarcity in times of abundance

    1. Andrew M. Sugden

    For communities living along the Amazon, greater seasonal fluctuations in water levels brought by climate change are likely to make access to fish resources more challenging.

    PHOTO: ROBERTHARDING/ALAMY STOCK PHOTO

    A cornerstone of food security is stability of access to the food supply. In a pioneering study of fishing communities in Amazonian seasonally flooded forest, Tregidgo et al. show how seasonal fluctuations in access can lead to scarcity even when the resource is abundant. Fishing becomes more challenging in the high-water season, leading to severe food insecurity for the more deprived households in the community. Communities such as these that depend on a wildlife resource for a substantial proportion of their diet may become further disadvantaged as seasonal fluctuations in access to food become further exacerbated by climate change.

    People Nat. 10.1002/pan3.10086 (2020).

  4. Parasitology

    How helminths trump diabetes

    1. Caroline Ash

    The prevalence of type 2 diabetes mellitus (T2DM) is inversely correlated with helminth infections in Asia. This may be because helminths have an immunomodulatory effect and thus dampen the type 1 (allergic type) immune responses underlying the proinflammatory state of T2DM. To test this idea, Rajamanickam et al. measured plasma levels of cytokines in 60 individuals living in rural India infected with Strongyloides stercoralis, a persistent nematode gut parasite, which in most people is symptomless. They compared these results with plasma cytokine concentrations from 58 T2DM patients showing no worm infection. Parasitized individuals showed significantly increased levels of interleukin-1 receptor alpha (IL-1Rα), which is typical of type 2 immune responses, and low levels of a wide range of proinflammatory cytokines and chemokines. When diabetic subjects were treated for parasites, their proinflammatory state, typically marked by increased IL-1β and IL-6, partially rebounded.

    PLOS Neg. Trop. Dis. 14, e0008101 (2020).

  5. Immunology

    Neutrophils avoid a traffic jam

    1. Seth Thomas Scanlon

    Neutrophils are the most abundant immune cell in the circulation and are typically the first responders to sites of infection or injury. How large numbers of neutrophils can efficiently travel through capillary networks is a mystery. Wang et al. investigated neutrophil trafficking in mouse liver using intravital microscopy and found that groups of neutrophils diverged at capillary bifurcations by traveling in an alternating pattern. This phenomenon was then studied in a controlled fashion using microfluidic chips connected to a chemoattractant chamber. Neutrophils were able to bias the decisions made by their companions at bifurcations by altering both hydraulic resistance and chemoattractant gradients. It is likely that similar mechanisms are widely used to coordinate complex immune responses.

    Nat. Commun. 11, 2385 (2020).

  6. Exoplanet Atmospheres

    Different as night and day

    1. Keith T. Smith

    The atmospheric compositions of exoplanets are usually determined by the technique of transit spectroscopy: When the planet transits between its host star and Earth, starlight passes through its atmosphere close to local dawn and dusk, imprinting additional absorption lines on the stellar spectrum. Pluriel et al. considered how the results are affected if the star heats the planet enough for atmospheric molecules to be dissociated on the planet's day side and recombine on the night side. They found that transit spectroscopy then produces highly biased atmospheric compositions differing from the true values by up to three orders of magnitude. More sophisticated methods are needed to determine the atmospheric compositions of hot exoplanets.

    Astron. Astrophys. 636, A66 (2020).

  7. Scientific Workforce

    To a postdoc and beyond

    1. Melissa McCartney

    To be a postdoctoral fellow today is to exist between a short-term research position and the reality of the academic job market. Nowell et al. sought to identify professional development (PD) opportunities used by postdocs to navigate a changing career landscape. Using quantitative and qualitative data collected from more than 500 current postdocs, the authors show that although postdocs engaged in diverse PD opportunities, these strategies were not always useful or career enhancing. By describing postdoc perceptions of PD, in parallel with their perceived usefulness, this study provides a comprehensive understanding of the misalignment of postdoc needs with available opportunities and can serve as a manual for helping academic institutions direct valuable resources toward the most effective postdoc PD strategies.

    Palgrave Commun. 6, 95 (2020).

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