A privileged status for animate objects
- Gilbert Chin
Some stimuli are so important that they capture our attention and influence how we think even when we perform an unrelated task. Moving geometric shapes, especially if moving in what appear to be a self-directed fashion, are invariably perceived to be animate, as though they represent live agents. Using “wolfpack” animations of dart shapes whose points track the movement of a disc (the prey), van Buren and Scholl show that these are more readily remembered than identical animations in which the dart points are oriented away from or perpendicular to the prey. Perceiving such moving shapes as animate reinforces visual memory and has possibly been important in human evolution.
Cognition 163, 87 (2017).
- Cerebral Organoids
The making of the human brain
- Beverly A. Purnell
The human brain differs greatly from those of other species in the development of a strikingly expanded and extensively folded cerebral neocortex. This feature is considered to underpin humans' augmented intellectual capacity. Human ventricular and subventricular zones also contain more radial glial cells and intermediate progenitors than those of other mammals. To investigate the development of cortical folding, Yu et al. used a three-dimensional culture system to generate cerebral organoids from pluripotent human stem cells. They found that mutations in growth factor signaling—specifically, deletion of PTEN activation of the PI3K-AKT pathway—increased cell-cycle reentry and expanded radial glia and intermediate progenitor populations. The resulting neural progenitor proliferation led to expanded and folded cerebral organoids. Inoculation of the organoids with Zika virus impaired cortical growth and folding.
Cell Stem Cell 20, 385 (2017).
- Local Sea Level
Planning for a rise
- H. Jesse Smith
Coastal areas affected by rising seas are subject to regional variations in sea level, as well as the global mean rise. In fact, local effects that occur over decades, rather than centuries, can be several times larger than the global one. Nieves et al. provide a tool to help coastal planners estimate the magnitudes of these regional sea level variations. They show that upper ocean temperature is a key indicator of changes in short-term sea level rise over large coastal regions of the United States. This information should enable more informed adaptation over time scales relevant to decision-makers.
J. Clim. 10.1175/JCLI-D-16-0896.1 (2017).
Menstrual cycle on a chip
- Megan Eldred
The female reproductive system is dynamic and complex. Various tissues secrete and respond to hormones to coordinate the 28-day menstrual cycle. This normal physiology has been difficult to study, but Xiao et al. have replicated the reproductive tract in a microfluidic device that they call EVATAR. The tissue culture-based model supports growth and function of ovary, fallopian tube, uterus, cervix, and liver for up to 100 days. Via interconnected modules, the cultured tissues respond to signals produced by each of the other organ cultures. This tool will provide researchers with exciting opportunities to perform pharmacological and toxicology studies on a physiologically relevant model of the human reproductive system.
Nat. Commun. 10.1038/ncomms14584 (2017).
- Global Sea Level
Rise on the rise
- H. Jesse Smith
One of the most important consequences of global warming is sea level rise, and better determining how fast it is occurring is vital for understanding the climate system and formulating adaptive policy. Dieng et al. used 26 separate data sets to determine global mean sea level (GMSL) since October 1992, when satellite altimetry measurements of sea levels began. They find that although the average rate of GMSL rise between January 1993 and December 2015 was close to 3.0 mm/year, the rate was 0.8 mm/year higher during the period 2004–2015 than it was during 1993–2004. Most of that increase was due to mass loss from the Greenland Ice Sheet, but all other components of the budget contributed as well.
Geophys. Res. Lett. 10.1002/2017GL073308 (2017).
- Cell Death
- Lisa D. Chong
The final insult during the mammalian cell death process called necroptosis is loss of membrane integrity. What happens next is uncontrolled release of cytoplasmic contents into the extracellular space. Gong et al. report that cells can delay this final step by recruiting cellular machinery to generate membrane buds. Execution of necroptosis involves the localization of an enzyme called MLKL (mixed lineage kinase domain-like) to the plasma membrane. MLKL recruits components of the endosomal sorting complexes required to transport ESCRT-III to the degrading membrane. ESCRT-III sustains membrane integrity by forming membrane blebs, which are eventually shed by the cell. Thus, ESCRT-III recruitment may buy time for the cell to signal to other cells before death. The work also indicates possible interventions to prevent cell death.
Cell 169, 286 (2017).
Virtues of splitting up water-splitting
- Jake Yeston
Widespread use of solar power will require a convenient means of storing energy for use at night and on rainy days, and making hydrogen fuel from water is a clean prospective solution. Most current approaches split the water into hydrogen and oxygen in the same apparatus, with a membrane keeping the two mutually explosive gases apart. Landman et al. instead separated the half reactions entirely, linking the two cells with a pair of nickel-based electrodes of the sort used in rechargeable alkaline batteries. Because these cells require only an electrical connection, the setup could potentially enable centralized hydrogen production powered by far-flung arrays of solar cells where the oxygen would be released.
Nat. Mater. 10.1038/NMAT4876 (2017).