Editors' Choice

Science  23 Nov 2018:
Vol. 362, Issue 6417, pp. 906
  1. Regeneration

    The making of a salivary gland

    1. Beverly A. Purnell

    Organoids can be used to regenerate salivary gland tissue.

    IMAGE: STEVE GSCHMEISSNER/SCIENCE SOURCE

    Several glands in the body generate and release material via a duct. The salivary gland represents one such exocrine gland, which is composed of several cell types and has a specific role in digestion and swallowing. Regenerative therapies are needed for salivary glands because various diseases and medical procedures can compromise their function. Tanaka et al. used organoid technology to regenerate salivary gland tissue in mice. Sox9 and Foxc1 were identified as organ-inductive signals that mediated the differentiation of mouse embryonic stem cells into induced salivary gland primordium (iSG). When iSGs were transplanted into mice lacking salivary glands, the transplanted iSGs looked like normal embryonic salivary gland rudiments and secreted saliva.

    Nat. Comm. 9, 4216 (2018).

  2. Physiology

    Could microbes be diabetogenic?

    1. L. Bryan Ray

    Microbes that live in the gut secrete metabolites that enter the bloodstream and may influence the health of the host organism. Koh et al. found that human gut microbes can produce the amino acid metabolite imidazole propionate, which is abundant in blood from human patients with type 2 diabetes and might contribute to their disease. Germ-free mice injected with imidazole propionate developed glucose intolerance and disrupted insulin signaling, like the diabetic patients. Imidazole propionate appeared to act, at least in part, through the p38γ mitogen-activated protein kinase to activate the mechanistic target of rapamycin complex 1 (mTORC1) protein kinase complex.

    Cell 175, 947 (2018).

  3. Microfluidics

    Flexibility via fiber drawing

    1. Marc S. Lavine

    Traditional microfluidic devices are fabricated either by building up layers or by etching solid materials, but both ways primarily result in devices with rectangular, triangular, or circular cross sections and limited flow geometries. Yuan et al. show that complex shapes like crosses and stars or even arbitrary shapes can be designed into millimeter-scale objects and then reduced in dimension, but not in cross-sectional profile, through a fiber drawing process. Channels with concave cross sections were used to study inertial flow effects, whereas coextrusion of conductive wires allowed for inertial dielectrophoretic particle manipulation. Sorted particles could then be extracted through the addition of a fiber-to-world connector that can split flow streams without disturbing the laminar flow.

    Proc. Natl. Acad. Sci. U.S.A. 115, E10830 (2018).

  4. Diversity

    What's good for me is good for you

    1. Melissa McCartney

    U.S. funding agencies are committed to bringing gender equality to STEM. As these programs begin to mature, is there evidence that they benefit more than just the women involved? Smith et al. designed and tested a gender-diversity program that supported the autonomy, relatedness, and competence of female faculty. Over the course of 3 years, researchers collected data from male and female tenure track faculty involved with the program and found positive changes in job satisfaction over time for everyone. Specifically, the more a faculty member felt involved with the project, the more positive changes were reported, suggesting that although diversity programs may target only one group, the results can have positive impacts on everyone who feels involved.

    J. Divers. High. Educ. 10.1037/dhe0000066 (2017).

  5. Nanomaterials

    Subnanometer WS2 pores

    1. Phil Szuromi

    Nanopores in monolayers of transition metal dichalcogenides such as molybdenum disulfide (MoS2) and tungsten disulfide (WS2) have potential applications in molecular separations, but how small can the pores be made? For example, defects created by removal of single Mo atoms from MoS2 are refilled by mobile Mo atoms. Ryu et al. used electron-beam irradiation in a transmission electron microscope to remove single W atoms from a monolayer WS2 sheet. At 500°C, which is sufficient to allow some sulfur vacancy migration, bond rearrangements created either smaller triangular or larger circular subnanometer pores that were stabilized in part through W–W bonding and by bond rotations about the pore periphery. The triangular holes were less stable and, under irradiation, evolved into the circular structures.

    ACS Nano 10.1021/acsnano.8b07051 (2018).

  6. Neurodevelopment

    Gender in the brain

    1. Pamela J. Hines

    The hippocampus of the brain is important for higher-order cognitive function, such as learning and memory. Derangements in this region are associated with autism spectrum, attention-deficit hyperactivity disorder, and epilepsy. While looking at the development of neurons during formation of the hippocampus in mice, Chung and Bailey found differences between males and females. In the early postnatal period, when hippocampal circuitry is being built, these neurons depend on signaling through nicotinic acetylcholine receptors. Whole-cell electrophysiology showed that these nascent hippocampal neurons in female mice showed greater excitability, higher resting membrane potential, and greater input resistance than neurons of male mice. These sex-dependent differences occurred during development of circuits that, at maturity, facilitate cognitive functions.

    Dev. Neurobiol. 10.1002/dneu.22646 (2018).

  7. Microbiota

    Model for maintaining integrity

    1. Caroline Ash

    The relationships between the gut microbiota, host cells, and food are complicated. Dissecting these interactions is impossible in mice, let alone in humans. Shin and Kim developed a human “gut inflammation–on-a-chip” microfluidic model, complete with villi and peristalsis to explore gut biology. They investigated events following application of the irritant dextran sodium sulfate (DSS), which is often used in mice to stimulate gut inflammation. By disrupting the chip epithelium and removing mucus, DSS facilitated contact between the dissociated epithelial cells and peripheral immune cells and triggered oxidative stress. In the presence of Escherichia coli, the epithelial cells produced inflammatory cytokines. After removal of DSS, epithelial regrowth and mucus production restored gut barrier function within days, but probiotics were only helpful before DSS was applied.

    Proc. Natl. Acad. Sci. U.S.A. 115, E10539 (2018).

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