This Week in Science

Science  19 Sep 2014:
Vol. 345, Issue 6203, pp. 1463
  1. Climate Change

    Rings of ocean upwelling

    1. H. Jesse Smith

    Growth rings in blue oaks like this one provide a climate record

    CREDIT: DANIEL GRIFFIN

    Coastal upwelling along the coast of California has become more variable than during nearly any period in the past 600 years. Black et al. used a 576-year tree ring record to construct a record of wintertime climate along the California coast. Because wintertime climate and coastal upwelling are so closely linked there, they were able to determine that upwelling variability has increased more over the past 60 years than for all but two intervals during that time. The apparent causes of the recent trend appear to be unique, resulting in reduced marine productivity and negative impacts on fish, seabirds, and mammals.

    Science, this issue p. 1498

  2. Nuclear Chemistry

    A carbonyl compound that tips the scales

    1. Jake Yeston

    Life is short for the heaviest elements. They emerge from high-energy nuclear collisions with scant time for detection before they break up into lighter atoms. Even et al. report that even a few seconds is long enough for carbon to bond to the 106th element, seaborgium (see the Perspective by Loveland). The authors used a custom apparatus to direct the freshly made atoms out of the hot collision environment and through a stream of carbon monoxide and helium. They compared the detected products with theoretical modeling results and conclude that hexacarbonyl Sg(CO)6 was the most likely structural formula.

    Science, this issue p. 1491; see also p. 1451

  3. Immunotherapy

    Cancer immunotherapy expands T cell attack

    1. Angela C. Colmone

    Patients with advanced melanoma can survive longer after treatment with the immunotherapy drug ipilimumab. Kvistborg et al. show how this therapeutic antibody exerts its beneficial effects. Although directed against an immune inhibitor, the drug unexpectedly failed to increase the magnitude of immune T cell responses. Rather, the patients' T cells targeted a greater variety of antigens. This increased breadth of the T cell response suggests that ipilimumab works by activating T cells directed against previously untargeted tumor-related antigens, rather than by boosting preexisting immune responses. If so, similar strategies could be successful in battling other cancers.

    Sci. Transl. Med. 6, 254ra128 (2014).

  4. Quantum Gases

    Aligning a magnetic atomic gas

    1. Jelena Stajic

    When a bunch of fermions get together, they obey the Pauli exclusion principle: No two fermions can be in the same quantum state. The fermions populate the available states, starting from those lowest in energy. The boundary between the empty and filled states is called the Fermi surface (FS). For cold gases of fermionic atoms in the lab, the FS is usually spherical. Now, Aikawa et al. observe the FS squishing in a gas of Er atoms, which behave like tiny magnets and align with their magnetic field environment. The squishing reflects the very directional interactions between the Er atoms.

    Science, this issue p. 1484

  5. Social Science

    The file drawer is full. Should we worry?

    1. Gilbert Chin

    Experiments that produce null results face a higher barrier to publication than those that yield statistically significant differences. Whether this is a problem depends on how many null but otherwise valid results might be trapped in the file drawer. Franco et al. use a Time-sharing Experiments in the Social Sciences archive of nearly 250 peer-reviewed proposals of social science experiments conducted on nationally representative samples. They find that only 10 out of 48 null results were published, whereas 56 out of 91 studies with strongly significant results made it into a journal.

    Science, this issue p. 1502

  6. Cord Blood Expansion

    Human adult stem cell expansion

    1. Beverly A. Purnell

    Cord blood is valued for stem cells

    PHOTO: DAVID SCHARF/SCIENCE SOURCE

    Transfused blood saves lives. Despite the widespread use of this critical resource, it is difficult to increase blood cell numbers outside of the body. By screening thousands of small compounds, Fares et al. identify a molecule that expands human stem cell numbers in cord blood. The researchers generate many variations of that molecule and show that one such compound provides even greater human blood cell expansion. If researchers can provide increased numbers of stem cells and progenitor cells, cord blood should find even greater use in the clinic.

    Science, this issue p. 1509

  7. Neuromuscular Disease

    Building connections by gene therapy

    1. Paula A. Kiberstis

    Voluntary movement requires a molecular conversation between nerves and muscles. This conversation occurs at the neuromuscular junction, a structure where nerves and muscle physically connect. People with diseases characterized by muscle weakness have aberrantly small neuromuscular junctions. Arimura et al. used gene therapy to enlarge the neuromuscular junction, which made muscles stronger. Studying mouse models of two distinct neuromuscular disorders, they used an adenovirus vector to deliver DOK7, a gene required for formation of the neuromuscular junction. The therapy improved the mice's motor activity and life span.

    Science, this issue p. 1505

  8. Sepsis

    One protein smothers other deadly ones

    1. John F. Foley

    Sepsis is a condition in which the body responds to infection with inflammation, which then spirals out of control. During sepsis, dead cells release histones, proteins normally found in the nucleus, which can kill nearby healthy cells. Daigo et al. discovered that a protein found in the circulation called pentraxin 3 interacted with histone proteins. Pentraxin 3 bundled the histones into aggregates that no longer killed healthy cells. When the researchers injected pentraxin 3 into mice with sepsis, the mice had less inflammation and survived. Thus, pentraxin 3 might be an effective therapy against sepsis in humans.

    Sci. Signal. 7, ra88 (2014).

  9. Gene Repression

    Establishing memory of gene repression

    1. Beverly A. Purnell

    Although cells in the body contain the same DNA content, they can display widely varying form and function among tissues. This comes about by differential gene regulation and by establishing a type of gene expression memory that is passed down during cell division to daughter cells. Gaydos et al. report that in nematodes, both sperm and oocytes transmit a memory of chromatin repression to embryos in the form of modified histones. During DNA replication, modified histones are passed to daughter chromatids to provide chromatin memory for a few cell divisions. Histone-modifying enzymes replenish histone modifications and provide long-term chromatin memory.

    Science, this issue p. 1515

  10. DNA Biochemistry

    Regulating DNA building blocks

    1. Guy Riddihough

    The bulding blocks of DNA, deoxynucleotide triphosphates, are synthesized by the enzyme ribonucleotide reductase (RNR). Its central role in DNA synthesis and its aberrant expression in tumors have made it an important anticancer target, but nucleoside analog inhibitors of RNR can have adverse side effects. Arnaoutov and Dasso identify IRBIT (IP3-receptor-binding protein released with inositol 1,4,5-trisphosphate) as an RNR-binding protein. IRBIT regulates the activity of RNR by stabilizing the inactive form bound to deoxyadenosine triphosphate in the low-affinity A site. In turn, phosophorylation of IRBIT regulates its RNR-binding activity. IRBIT provides a new target for RNR inhibition that might avoid some of the side effects of current drugs.

    Science, this issue p. 1512

  11. Quantum Simulation

    Studying magnetism with cold atoms

    1. Jelena Stajic

    Physicists have used cold atomic gases to simulate quantum phenomena that we normally associate with much more complex systems, such as solid-state materials. Because the properties of these gases are so tunable, it is also possible to create conditions that otherwise do not exist in nature. Zhang et al. studied an exotic type of magnetism in an array of pancake-shaped atomic clouds of 87Sr. They prepared the atoms' nuclei in different combinations of 10 quantum states. They then shone pulses of light at the atoms to deduce the properties of the atoms' interactions. The interactions were independent of the atoms' nuclear states—a hallmark of an unusual symmetry that theorists predict may lead to interesting collective effects.

    Science, this issue p. 1467

  12. Organic Electronics

    Organic semiconductors go out for a spin

    1. Jake Yeston

    Magnetism is a commonly observed phenomenon in the macroscopic world, but its origins lie in the quirky quantum-mechanical property of electrons and certain nuclei known as spin. Recent research has sought to leverage and expand the role of spin in the operation of electronic devices. Malissa et al. used a highly sensitive spectroscopic technique to probe, and ultimately manipulate, the subtle effects of spin interactions on the current that flows through organic light-emitting diodes (OLEDs) (see the Perspective by Bobbert). They pinpointed coupling between the spins of the current carriers and the hydrogen nuclei in the hydrocarbon-based material making up the device.

    Science, this issue p. 1487; see also p. 1450

  13. Mood Regulation

    A pathway that controls our mood

    1. Peter Stern

    A brain area called the lateral habenula is involved in negative motivation and may thus play a role in depression. Shabel et al. investigated synaptic transmission in a brain pathway to the lateral habenula that transmits disappointment signals. Surprisingly, they found the simultaneous release of two antagonistic substances, glutamate and GABA, from individual nerve cells. In an animal model of depression, GABA release was reduced in this pathway. A widely used antidepressant drug, however, increased GABA co-release. These results reveal an unusual synaptic mechanism that affects lateral habenula activity. This mechanism may be instrumental for regulating the emotional impact of disappointment.

    Science, this issue p. 1494

  14. Structural Biology

    A foreign-DNA–destroying machine

    1. Guy Riddihough

    Bacteria have an adaptive immune system, called CRISPR, that identifies invading viruses through their DNA or RNA sequences and cuts them up (see the Perspective by Zhang and Sontheimer). Jackson et al. and Mulepati et al. have determined the structure of the large protein complex, called Cascade, that targets the invading nucleic acids and does the cutting. The seahorse-shaped structure reveals how the 11 subcomponents of Cascade assemble into the final protein complex. The structure also shows how Cascade presents the short CRISPR-derived RNAs so that they can bind and target foreign DNA.

    Science, this issue p. 1473 and p. 1479; see also p. 1452

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