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<jats:p> Thin adherent films formed from ferric ions and a natural polyphenol, tannic acid, can coat a wide variety of surfaces. <jats:named-content content-type="related-content"> [Also see Perspective by <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6142" page="136" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1241562">Bentley and Payne</jats:related-article> ] </jats:named-content> </jats:p>

<jats:title>Ionic Materials via Charged Clusters</jats:title> <jats:p> The formation of salts from atomic and small molecular ions could in principle be replicated with larger inorganic clusters. However, many clusters are stabilized by organic ligands that create a barrier for charge transfer reactions to create ions. <jats:bold> Roy <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6142" page="157" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1236259">157</jats:related-article> , published online 6 June; see the Perspective by <jats:bold> <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6142" page="135" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1240813">Batail</jats:related-article> </jats:bold> ) now report that chromium, cobalt, and nickel selenide and telluride clusters form materials by charge transfer with C <jats:sub>60</jats:sub> . The Co and Cr clusters formed a layered structure analogous to CdI <jats:sub>2</jats:sub> , while the Ni cluster formed a structure related to NaCl. </jats:p>

<jats:title>From Jawless to Jawed</jats:title> <jats:p> The earliest vertebrates were jawless. Past reconstructions have assumed that the primitive jawed condition was much like that found in sharks. <jats:bold> Trinajstic <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6142" page="160" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1237275">160</jats:related-article> , published online 13 June; see the Perspective by <jats:bold> <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6142" page="139" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1241451">Kuratani</jats:related-article> </jats:bold> ) describe fossil musculature from the early jawed placoderms (an extinct class of armored prehistoric fish) that show that the basal structure was distinct from that found in sharks, having a notable dermal joint between the skull and shoulder girdle. </jats:p>

<jats:title>Movers and Shakers</jats:title> <jats:p> We tend to view earthquakes as unpredictable phenomena caused by naturally shifting stresses in Earth's crust. In reality, however, a range of human activity can also induce earthquakes. <jats:bold>Ellsworth</jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" related-article-type="in-this-issue" xlink:href="10.1126/science.1225942">10.1126/science.1225942</jats:related-article> ) reviews the current understanding of the causes and mechanics of earthquakes caused by human activity and the means to decrease their associated risk. Notable examples include injection of wastewater into deep formations and emerging technologies related to oil and gas recovery, including hydraulic fracturing. In addition to directly causing increased local seismic activity, activities such as deep fluid injection may have other ramifications related to earthquake occurrence. <jats:bold> Van der Elst <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6142" page="164" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1238948">164</jats:related-article> ; see the news story by <jats:bold> <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6142" page="126" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.2013.341.6142.341_126">Kerr</jats:related-article> </jats:bold> ) demonstrate that in the midwestern United States, some areas with increased human-induced seismicity are also more prone to further earthquakes triggered by the seismic waves from large, remote earthquakes. Improved seismic monitoring and injection data near deep disposal sites will help to identify regions prone to remote triggering and, more broadly, suggest times when activities should, at least temporarily, be put on hold. </jats:p>

<jats:title>Inward-Facing Antiporter</jats:title> <jats:p> Calcium/cation antiporters play a role in regulating the cytosolic calcium concentration by using the electrochemical gradient of other cations to catalyze Ca <jats:sup>2+</jats:sup> transport across cell membranes. The structure of a Na <jats:sup>+</jats:sup> /Ca <jats:sup>2+</jats:sup> exchanger in an outward-facing conformation was recently determined. <jats:bold> Nishizawa <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6142" page="168" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1239002">168</jats:related-article> , published online 23 May) now report the crystal structure of a H <jats:sup>+</jats:sup> /Ca <jats:sup>2+</jats:sup> exchanger in an inward-facing conformation. Comparison of the structures shows how structural changes create hydrophilic cavities to alternate between the intra- and extracellular sides of the protein, facilitating cation transport. </jats:p>

<jats:title>Keeping the Inflammasome in Check</jats:title> <jats:p> Nucleotide-binding and oligomerization domain (NOD)–like receptors (NLRs) play an important role in the detection of pathogens by cells of the innate immune system. For several NLR family members, activation results in relief from autoinhibition, oligomerization, and the recruitment of signaling components that together make up the inflammasome, a large multiprotein complex. The inflammasome protects the host by inducing cell death and cytokine secretion. The specific molecular mechanisms that regulate NLR activation and inhibition, however, are not well understood. <jats:bold> Hu <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6142" page="172" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1236381">172</jats:related-article> , published online 13 June) report the crystal structure of autoinhibited NLR family member NLRC4, which reveals the domains that are critical for interaction with adenosine diphosphate to keep NLRC4 in its inactive state and the domains that mediate oligomerization of the protein upon activation. </jats:p>

<jats:title>From Nasty to Tasty</jats:title> <jats:p> Some of our favorite food crops derive from wild relatives that were distasteful or even toxic. Domestication over many years selected for variants with reduced levels of antinutritional compounds. The wild relatives remain valuable, however, for other traits such as resistance to pathogens, but their use in crop development is complicated by the continued presence of unpalatable compounds. <jats:bold> Itkin <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6142" page="175" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1240230">175</jats:related-article> , published online 20 June) elucidate the metabolic pathways and genes directing synthesis of some of these antinutritionals in potato and tomato. </jats:p>

<jats:title>Leprosy: Ancient and Modern</jats:title> <jats:p> In medieval Europe, leprosy was greatly feared: Sufferers had to wear bells and were shunned and kept isolated from society. Although leprosy largely disappeared from Europe in the 16th century, elsewhere in the world almost a quarter of a million cases are still reported annually, despite the availability of effective drugs. <jats:bold> Schuenemann <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6142" page="179" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1238286">179</jats:related-article> , published online 13 June; see the 14 June News story by <jats:bold>Gibbons</jats:bold> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6138" page="1278" related-article-type="in-this-publication" vol="340" xlink:href="10.1126/science.2013.340.6138.340_1278">1278</jats:related-article> ) probed the origins of leprosy bacilli by using a genomic capture-based approach on DNA obtained from skeletal remains from the 10th to 14th centuries. Because the unique mycolic acids of this mycobacterium protect its DNA, for one Danish sample over 100-fold, coverage of the genome was possible. Sequencing suggests a link between the middle-eastern and medieval European strains, which falls in line with social historical expectations that the returning expeditionary forces of antiquity originally spread the pathogen. Subsequently, Europeans took the bacterium westward to the Americas. Overall, ancient and modern strains remain remarkably similar, with no apparent loss of virulence genes, indicating it was most probably improvements in social conditions that led to leprosy's demise in Europe. </jats:p>

<jats:title>Avian Flu in Ferrets</jats:title> <jats:p> A recent outbreak of avian H7N9 influenza in humans in eastern China has been closely monitored for any evidence of human-to-human transmission and its potential for sparking a pandemic. <jats:bold> Zhu <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6142" page="183" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1239844">183</jats:related-article> , published online 23 May) examined the behavior of the avian virus in the ferret, a mammalian model for human influenza. The virus was excreted by the ferrets and could be transmitted readily by contact but displayed limited capacity for airborne infectivity. The pathology of H7N9 is similar to H1N1, and it seems that factors other than the intrinsic pathogenicity of the virus contribute to the reported high fatality rate. </jats:p>

<jats:title>Magnesium to the Rescue</jats:title> <jats:p> Individuals with X-linked immunodeficiency with Mg <jats:sup>2+</jats:sup> defect, Epstein-Barr virus (EBV) infection, and neoplasia (XMEN) disease are genetically deficient for expression of <jats:italic>MAGT1</jats:italic> , a magnesium transporter. <jats:bold> Chaigne-Delalande <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6142" page="186" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1240094">186</jats:related-article> ) sought to better understand why these individuals are chronically infected with EBV at high viral loads and are susceptible to the development of lymphomas. CD8 <jats:sup>+</jats:sup> T cells and natural killer cells, which help to keep EBV infection in check, exhibited reduced cytotoxicity owing to their lower expression of the cell surface receptor NKG2D, which triggers cytolysis upon ligation. Magnesium supplementation in vitro and also in two XMEN patients restored levels of free Mg <jats:sup>2+</jats:sup> , increased NKG2D expression, and resulted in reduced amounts of EBV <jats:sup>+</jats:sup> cells, suggesting that this may be an effective therapeutic approach for XMEN patients. </jats:p>