# This Week in Science

Science  01 Mar 2019:
Vol. 363, Issue 6430, pp. 941
1. Fisheries

# Accounting for a warming ocean

1. Sacha Vignieri

Fisheries provide food and support livelihoods across the world. They are also under extreme pressure, with many stocks overfished and poorly managed. Climate change will add to the burden fish stocks bear, but such impacts remain largely unknown. Free et al. used temperature-specific models and hindcasting across fish stocks to determine the degree to which warming has, and will, affect fish species (see the Perspective by Plagányi). They found that an overall reduction in yield has occurred over the past 80 years. Furthermore, although some species are predicted to respond positively to warming waters, the majority will experience a negative impact on growth. As our world warms, responsible and active management of fisheries harvests will become even more important.

2. Metallurgy

# Pushing and pulling for high strength

1. Brent Grocholski

High-strength aluminum alloys are important for producing lightweight cars, trains, and airplanes. The traditional strategy for doing this is through hours of high-temperature cycling to form precipitates in the alloy. Sun et al. developed a processing method that relies on mechanical cycling by pushing and pulling on the alloys at room temperature. This quickly creates many very fine precipitates that have the same strengthening effect as those characteristic of traditional thermal methods. This method should also work for other alloy systems.

Science, this issue p. 972

3. Optics

# Making a (precision) measure of light

1. Ian S. Osborne

When measuring length, we learn in school that a vernier scale that uses two rulers, slightly offset, can reduce human estimation error and improve the resolution of a measurement. Yang et al. apply the same vernier principle with optical combs to develop a spectrometer that can determine the wavelength of light with high accuracy and precision. Two phase-locked counterpropagating optical microcombs generated in a miniature microresonator provided the rulers. Matching up of the “teeth” of the combs was then used to measure the wavelength of the optical light sources.

Science, this issue p. 965

4. Vocal Interaction

# Turn-taking in singing mice

1. Sacha Vignieri

The ability to take turns is a hallmark of social interaction among animals. It occurs in many different species, from dueting birds to frogs, and is a notable part of human speech. Such rapid response requires a complex cascade of sensory and motor actions that has been difficult to characterize. Okobi et al. examined turn-taking in tropical singing mice, in which males interrupt, and alter, each other's songs (see the Perspective by Hage). They describe an orofacial motor cortex that mediates rapid transition from the motor cortex to the vocal motor apparatus and facilitates rapid vocal interactions.

5. Immunometabolism

# Exosomes that fatten immune cells

1. Paula A. Kiberstis

Adipose tissue in mammals contains not only adipocytes (fat cells) but also a variety of immune cells—most notably, macrophages. Proper communication between these cell types is thought to be important for metabolic health. Flaherty et al. found that adipocytes release lipid-filled vesicles (AdExos) that serve as the primary source of lipid for adipose-resident macrophages (see the Perspective by Antonyak et al.). AdExos were present at low levels in the circulation of mice and were produced at twice the rate in obese versus lean animals. In vitro, AdExos induced differentiation of bone marrow precursor cells into cells resembling adipose-resident macrophages.

# Teaching baby B cells

1. Lindsey Pujanandez

Antibodies are central to immune defense. B cells can generate several antibody isotypes that fulfill different functional roles, and repeated antigen exposure induces antibody somatic hypermutation. Nielsen et al. studied a longitudinal birth cohort to determine how antigen exposure early in life affects human antibody production. Somatic hypermutation increased as the children got older, and certain VH genes were associated with different isotypes. Increased pathogen exposure was associated with immunoglobulin D (IgD) and IgM mutations. Interestingly, children with eczema or allergies had higher rates of IgE mutation. These valuable data shed light on how human B cells grow up.

Sci. Transl. Med. 11, eaat2004 (2019).

7. Ecological Economics

# Paris Agreement benefits to fishing

1. Kollen Post

Traditional arguments against environmentalist regulation often focus on the cost. However, Sumaila et al. estimated that implementing the Paris Agreement would be financially helpful to the world's fishing industry and to seafood consumers. They combined models of fish habitat, climate variation, and seafood prices given the two projections of 1.5°C increase in global temperatures, as stipulated by the Paris Agreement, and the 3.5°C anticipated if present trends continue. The authors conclude that the Paris Agreement would mean an extra $4.6 billion in revenue for fishers,$3.7 billion in wages for seafood workers, and \$6.3 billion in savings for consumers.

8. Outer Solar System

# Impact craters on Pluto and Charon

1. Keith T. Smith

Collisions between Solar System bodies produce impact craters on large objects at a rate that depends on the population of impacting small bodies. Singer et al. examined impact craters on Pluto and its moon Charon. Some regions have had their impact craters erased by recent geological processes, but others appear to record 4 billion years of impacts. Because Pluto and Charon are located in the Kuiper belt, the distribution of crater sizes reflects the size distribution of impacting Kuiper belt objects (KBOs). The authors found fewer small KBOs than predicted by models of collision equilibrium, implying that some of the KBO population has been preserved since the formation of the Solar System.

Science, this issue p. 955

9. Structural Biology

# Cool mechanism for sensing cool

1. Steve Mao

In humans, cold is primarily sensed by transient receptor potential melastatin member 8 (TRPM8), a calcium channel. Yin et al. present cryo–electron microscopy structures of TRPM8 with cooling agents, membrane lipid phosphatidylinositol-4,5-bisphosphate (PIP2), and calcium. Structural and functional analyses showed that the PIP2 binding site in TRPM8 is completely different from PIP2 sites in other TRP channels. The binding of PIP2 and cooling agents allosterically enhance each other and activate the channel opening. Thus, the activation mechanism of TRPM8 is distinct from that used by other TRP channels.

Science, this issue p. eaav9334

10. Climate

# Tropical interconnections

1. H. Jesse Smith

The El Niño–Southern Oscillation, which originates in the tropical Pacific, affects the rest of the world's tropics by perturbing global atmospheric circulation. Less appreciated than this influence is how the tropical Atlantic and Indian Oceans affect the Pacific. Cai et al. review what we know about these pantropical interactions, discuss possible ways of improving predictions of current climate variability, and consider how projecting future climate under different anthropogenic forcing scenarios may be improved. They argue that making progress in this field will require sustained global climate observations, climate model improvements, and theoretical advances.

Science, this issue p. eaav4236

11. Tectonics

# Ancient height of the Tibetan Plateau

1. Brent Grocholski

The elevation of the Tibetan Plateau has a major impact on climate, affecting the monsoons and regional weather patterns. Although some isotope proxies have suggested a roughly equivalent height for the plateau as far back as the Eocene (∼40 million years ago), other lines of evidence suggest a lower elevation in the distant past. Botsyun et al. used a model to show that several previously overlooked factors contribute to the isotopic record from the Eocene (see the Perspective by van Hinsbergen and Boschman). The results harmonize the isotopic record with other proxies and argue for a Tibetan Plateau that was about 1000 meters lower than it is today.

12. Biomedicine

# Sensitive sensing

1. Marc S. Lavine

Neonatal care, particularly for premature babies, is complicated by the infants' fragility and by the need for a large number of tethered sensors to be attached to their tiny bodies. Chung et al. developed a pair of sensors that only require water to adhere to the skin and allow for untethered monitoring of key vital signs (see the Perspective by Guinsburg). On-board data processing allowed for efficient wireless near-field communication using standard protocols. The absence of cables makes it easier to handle the infants and allows for skin-to-skin contact between the babies and their parents or caregivers.

13. Development

# Cytoneme signaling in fly development

1. L. Bryan Ray

During development of certain tissues in the fruit fly, signaling from one tissue to another appears to occur through specialized filopodia called cytonemes. The cytonemes contain receptors and reach close toward the signal-producing cells. Huang et al. report that components of neuronal signaling at synapses also function in proper formation of cytoneme appositions and signaling. Various manipulations of calcium signaling, expression of dominant-negative glutamate receptor proteins, or depletion of vesicle transport proteins or components of voltage-gated calcium channels influenced the presence of cytonemes and signaling.

Science, this issue p. 948

14. Nanomaterials

# Phases of multielement nanoparticles

1. Phil Szuromi

Thermodynamically stable metal nanoparticles composed of multiple elements could, in principle, exhibit several different phases that form multiple interfaces. Chen et al. explored the structure and composition of palladium-tin alloy nanoparticles formed with up to five other elements after high-temperature annealing. Triphase nanoparticles possessed two or three interface architectures, and tetraphase nanoparticles exhibited up to six interfaces. Theoretical and experimental studies revealed how the balance between surface and interfacial energies influences the observed phases and interface structure.

Science, this issue p. 959

15. Neutron Star Merger

# Merging produced a structured jet

1. Keith T. Smith

The binary neutron star merger event GW170817 was observed with gravitational waves and across the electromagnetic spectrum. However, the physical processes that produced that emission remain poorly understood, particularly the late-time x-ray and radio emission. Ghirlanda et al. observed the radio afterglow with an interferometric array of 32 radio telescopes spread across the globe. The size and position of the radio source are not compatible with a uniformly expanding cocoon, as some have suggested. Instead, the data indicate that GW170817 produced a structured jet of material that escaped the surrounding ejecta and is now expanding into the interstellar medium at relativistic speeds.

Science, this issue p. 968

16. Neuroscience

# Coupled ripples in memory

1. Peter Stern

Short-lived, high-frequency oscillations in the brain called ripples have been implicated as substrates for memory formation. There is, however, little evidence linking ripple activity with awake memory retrieval in humans. Vaz et al. analyzed intracranial recordings in human subjects (see the Perspective by Gelinas). They found that ripple oscillations in the brain's medial temporal lobe were coupled with ripple oscillations in the temporal cortex. This coupling was enhanced just before successful memory retrieval. During successful retrievals with ripples, patterns of oscillations were recapitulated across multiple electrodes, consistent with the initial encoding. The observation that ripple oscillations occur before successful memory retrieval suggests that they may play a mechanistic role in the retrieval process.

17. Immunology

# Stressed gut epithelium gets some relief

1. Seth Thomas Scanlon

Immunoglobulin A (IgA) is the most abundantly expressed antibody isotype and can be found at various mucosal surfaces in the body, including the gastrointestinal (GI) tract. IgA is polyreactive and can coat and restrain both commensal bacteria and enteric pathogens. Grootjans et al. found that endoplasmic reticulum (ER) stress in the intestinal epithelial cells of mice induced the T cell– and microbiota-independent expansion of peritoneal B1b cells, which secrete IgA. Similarly, human subjects homozygous for a variant of an autophagy gene (ATG16L1) known to cause ER stress showed increased numbers of GI IgA+ cells compared with controls. Thus, epithelial ER stress serves as an advantageous “eustress” response that can functionally antagonize its well-characterized role in promoting inflammation.

Science, this issue p. 993

18. Antibodies

# Engaging monocytes to battle Chikungunya

1. Anand Balasubramani

Antibody-binding receptors, including Fc receptors and complement receptors, play a central role in mediating antibody-dependent immune activation. Fox et al. examined the role of Fcγ receptors and complement component 1q (C1q) in meditating the therapeutic effects of monoclonal immunoglobulin G antibodies targeting Chikungunya virus. They used antibody engineering in conjunction with mouse strains lacking C1q or Fcγ receptors to show that the therapeutic effects of these antibodie s are dependent on expression of Fcγ receptors. Furthermore, depleting distinct immune cell types revealed that engagement of Fc receptors on monocytes is central in driving antibody-dependent viral clearance.

Sci. Immunol. 4, eaav5062 (2019).

19. Cancer

# Revisiting TGF-β and EMT

1. Leslie K. Ferrarelli

Cancer progression is enhanced by the epithelial-to-mesenchymal transition (EMT), a process mediated by transforming growth factor–β (TGF-β). EMT is thought to be a reversible process. However, Katsuno et al. found that TGF-β withdrawal did not reverse EMT induced by long-term exposure to TGF-β, which mimics what occurs during carcinoma progression. By contrast, an inhibitor of the kinase mammalian target of rapamycin reversed some EMT features in cells and metastatic breast cancer models in mice. These results may explain why TGF-β inhibitors are not effective in some cancer patients and highlight a potential alternative therapy.

Sci. Signal. 12, eaau8544 (2019).