Editors' Choice

Science  02 Feb 2018:
Vol. 359, Issue 6375, pp. 531
  1. Cell Biology

    Targeting the demise of male mitochondria

    1. L. Bryan Ray

    Confocal micrograph of Caenorhabditis elegans worms

    PHOTO: HEITI PAVES/SCIENCE SOURCE

    In the nematode worm Caenorhabditis elegans, as in humans, offspring inherit mitochondria and mitochondrial DNA only from their mother. Sato et al. identified key molecular components of the machinery that recognizes male mitochondria and targets them for degradation. In a screen for kinases that might be required for the process, they identified IKKE-1, a protein kinase with similarity to the mammalian protein kinases TBK1 and IKBKE. IKKE-1 interacted with a protein that they named ALLO-1, which had sequence similarity to autophagy receptors and was required for clearance of paternal organelles. The similarity of the role of IKKE-1 in removing male mitochondria to that of mammalian TBK1, which functions in the innate immune response, hints that the two processes might have a similar evolutionary origin.

    Nat. Cell Biol. 10.1038/s41556-017-0008-9 (2018).

  2. Immunology

    High caloric intake induces inflammation

    1. Gemma Alderton

    The consumption of high-calorie diets has become prevalent in industrialized nations and is associated with increased body mass, inflammation, and resulting pathologies. What are the underlying mechanisms connecting diets of high-energy, processed food to inflammation? Christ et al. show that mice fed on a high-calorie Western diet developed systemic inflammation and functionally reprogrammed granulocyte monocyte precursor cells. After a standard chow diet was restored to the animals, inflammation persisted, indicating that components in the Western diet induced innate immune memory. This study identifies possible targets for preventing diet-induced inflammation.

    Cell 172, 162 (2018).

  3. Ocean Physics

    Shear by the centimeter

    1. H. Jesse Smith

    Oil from the 2011 MV Rena spill surrounds a service vessel.

    PHOTO: NATURE PICTURE LIBRARY/ALAMY STOCK PHOTO

    Predicting the transport of oil and floating debris in the ocean is very difficult because it is challenging to measure differences in water motion very close to the surface. Laxague et al. present measurements of the ocean's current vector profile made in the Gulf of Mexico, showing that the velocity of the uppermost centimeter of the water column was four times that at a depth of 10 m and displaced by nearly 90°. Therefore, incorporating these kinds of dynamics into forecasting efforts is essential for better understanding the movement and fates of plastic particles and spilled oil in the oceans.

    Geophys. Res. Lett. 10.1002/2017GL075891 (2017).

  4. Comparative Genomics

    Using phylogeny to test evolution

    1. Laura M. Zahn

    Sequencing of whole genomes and obtaining information about gene transcription offer the promise to compare changes and variation in gene expression and function across species. However, Dunn et al. show that analyses of gene expression data that use pairwise comparisons across multiple species may not be able to distinguish between differing models of evolution. By examining published studies of how gene expression may change across species, they show that it is necessary to consider the mode of evolution—i.e., duplication generating paralogs or orthologous evolution through speciation—as well as the time since the species diverged. Thus, phylogenetic information is needed to discern commonalities and differences across species and among genes that share an ancestor but may have undergone different evolutionary trajectories.

    Proc. Natl. Acad. Sci. U.S.A. 10.1073/pnas.1707515115 (2018).

  5. Star Formation

    Many stars don't form in clusters

    1. Keith T. Smith

    Most stars are thought to form in dense, gravitationally bound molecular clouds, which should produce a bound cluster of stars. As unused gas is expelled from the system by stellar feedback, the cluster becomes gravitationally unbound to form an association, which gradually drifts apart. Associations of young stars (no more than a few million years old) should therefore be slowly expanding. Ward and Kruijssen use astrometric data to test this idea by looking for evidence of expansion in several nearby young associations. They do not find any; the associations show no sign of ever having been gravitationally bound. The authors suggest that this indicates that star formation is dominated by turbulent fragmentation, not monolithic collapse.

    Mon. Not. R. Astron. Soc. 10.1093/mnras/sty117 (2018).

  6. Antibiotics

    Recycling antibiotic sensitivity

    1. Caroline Ash

    Cystic fibrosis (CF) is accompanied by chronic lung infections, requiring lifelong consumption of many antibiotics to maintain airway function. Antibiotic resistance and clinical deterioration are apparently inevitable. In a multifactorial study, Imamovic et al. discovered that mutations in Pseudomonas aeruginosa that endow resistance to some classes of antibiotic concomitantly result in sensitivity to others. For example, in any strain of P. aeruginosa, resistance to the fluoroquinolone ciprofloxacin was consistently associated with sensitivity to aminoglycoside antibiotics, such as amikacin. In this case, resistance was mediated by mutations in the transcriptional regulator nfxB of the MexC transporter. Using biomarkers such as nfxB, it appears to be possible to design antibiotic regimens for individual CF sufferers that flip resistant bacteria between predictable drug-sensitive states.

    Cell 10.1016/j.cell.2017.12.012 (2018).

  7. Microbiology

    Cutting up in the deep

    1. Michael A. Funk

    Life in the deep ocean is cut off from sunlight as an energy source. Fixed carbon from the surface—namely, dead microbes and larger organisms—therefore serves as a source of energy at depths below the reach of sunlight. Bergauer et al. analyzed genomic and proteomic data from microorganisms collected at depths down to 4 to 5 km. Microbial transport proteins varied only slightly in abundance with depth, reflecting changes in the abundance of organisms and in lifestyle. Organic acid transporters were found throughout the water column and were more abundant in the deep ocean, suggesting that uptake of dilute dissolved organic matter is crucial for microbial metabolism at these depths.

    Proc. Natl. Acad. Sci. U.S.A. 10.1073/pnas.1708779115 (2018).