Catálogo de publicaciones - revistas

<jats:title>Sustaining stem cell identity</jats:title> <jats:p> Stem cells in the developing brain acquire identities according to their locations and the types of neurons they will generate. As the brain grows larger and more complex, these identities must be maintained. Delgado <jats:italic>et al.</jats:italic> found this positional identity to be sustained by an epigenetic memory system. A morphogen sets the stem cell's identity early in development, but the identity is sustained by epigenetics. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6486" page="48" related-article-type="in-this-issue" vol="368" xlink:href="10.1126/science.aba5960">48</jats:related-article> </jats:p>

<jats:title>Organelle cross-talk</jats:title> <jats:p> Endoplasmic reticulum (ER)–associated degradation (ERAD) is a quality control mechanism that allows for targeted degradation of proteins in the ER. Zhou <jats:italic>et al.</jats:italic> found that a particular protein complex in ERAD, Sel1L-Hrd1, regulates the dynamics of another organelle, the mitochondrion, by altering ER-mitochondria contacts. Three-dimensional high-resolution imaging in brown adipocytes from cold-challenged mice revealed that defective ERAD led to the formation of enlarged and abnormally shaped mitochondria with perforating ER tubules. The authors explored the consequences of ERAD deficiency on mitochondrial function and thermogenesis, which provides insights into ERADmediated ER-mitochondrial cross-talk and advances our understanding of the physiological importance of interorganelle contact. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6486" page="54" related-article-type="in-this-issue" vol="368" xlink:href="10.1126/science.aay2494">54</jats:related-article> </jats:p>

<jats:title>Seeing subtle nanoparticle differences</jats:title> <jats:p> A challenge in the fabrication of nanoparticles is that even for particles of uniform size, there will still be a distribution in the atomic arrangements and surface capping ligands from one particle to the next. Using liquid-cell transmission electron microscopy, Kim <jats:italic>et al.</jats:italic> reconstructed the structure of individual nanocrystals synthesized in one batch while they were still in solution. A comparison of multiple particles showed structural heterogeneity and differences between the interior and the outer shell of the individual nanoparticles, as well as nanoparticles containing extended defects and thus differences in internal strain, all of which can affect the physical and chemical properties of each particle. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6486" page="60" related-article-type="in-this-issue" vol="368" xlink:href="10.1126/science.aax3233">60</jats:related-article> </jats:p>

<jats:title>Blowing a crater in asteroid Ryugu</jats:title> <jats:p> The Hayabusa2 spacecraft was designed to collect samples from the nearby asteroid (162173) Ryugu and return them to Earth for laboratory analysis. Arakawa <jats:italic>et al.</jats:italic> describe how the spacecraft's Small Carry-on Impactor was fired into the asteroid's surface, producing an artificial impact crater. Analysis of the resulting plume of ejecta, recorded by a remote camera, sets an upper limit on the strength of the rubble-pile surface. The crater has a semicircular shape, probably due to a large boulder buried close to the impact location. The crater exposed material from Ryugu's subsurface, which has not been subjected to space weathering, that is suitable for collection by Hayabusa2. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6486" page="67" related-article-type="in-this-issue" vol="368" xlink:href="10.1126/science.aaz1701">67</jats:related-article> </jats:p>

<jats:title>Straining an oxide membrane</jats:title> <jats:p> Perovskite manganites, such as La <jats:sub>0.7</jats:sub> Ca <jats:sub>0.3</jats:sub> MnO <jats:sub>3</jats:sub> , have complex phase diagrams with many competing states. Among the knobs that can be used to control their properties are magnetic field and strain. Hong <jats:italic>et al.</jats:italic> placed membranes of La <jats:sub>0.7</jats:sub> Ca <jats:sub>0.3</jats:sub> MnO <jats:sub>3</jats:sub> on a flexible polymer layer (see the Perspective by Beekman). Stretching the flexible layer resulted in large strains of up to 8% on the membrane. By varying the magnitude and direction of the strain, the researchers were able to explore the phase diagram of the system and influence its magnetic and transport properties. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6486" page="71" related-article-type="in-this-issue" vol="368" xlink:href="10.1126/science.aax9753">71</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6486" page="32" related-article-type="in-this-issue" vol="368" xlink:href="10.1126/science.aba6469">32</jats:related-article> </jats:p>

<jats:title>Slipping on till</jats:title> <jats:p>How do glaciers flow over the ground underlying them? We know that friction, ice stream velocity, and water pressure at the ice bed all matter, but we still do not know how to represent the process over both hard beds (which are solid rock) and soft ones (composed of unconsolidated erosion products called till). Zoet and Iverson present experimental results describing how glacial ice moves over watersaturated till (see the Perspective by Minchew and Joughin). These observations should help to solve the long-standing problem of constructing a generalized slip law that combines the processes of hard-bedded sliding and bed deformation.</jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6486" page="76" related-article-type="in-this-issue" vol="368" xlink:href="10.1126/science.aaz1183">76</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6486" page="29" related-article-type="in-this-issue" vol="368" xlink:href="10.1126/science.abb3566">29</jats:related-article> </jats:p>

<jats:title>Designer gates</jats:title> <jats:p> Signaling in cells can occur through protein-protein interactions. Chen <jats:italic>et al.</jats:italic> describe the design of logic gates that can regulate protein association. The gates were built from small, designed proteins that all have a similar structure but where one module can be designed to interact specifically with another module. Using monomers and covalently connected monomers as inputs and encoding specificity through designed hydrogen-bond networks allowed the construction of two-input or three-input gates based on competitive binding. The modular control elements were used to regulate the association of elements of transcription machinery and split enzymes in vitro and in yeast cells. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6486" page="78" related-article-type="in-this-issue" vol="368" xlink:href="10.1126/science.aay2790">78</jats:related-article> </jats:p>

<jats:title>Ferroptotic cell death and cancer</jats:title> <jats:p> Cell death can occur through different mechanisms, several of which are being explored as potential targets for cancer treatment. One form of cell death that has attracted recent interest is ferroptosis, which is triggered by high intracellular levels of lipid reactive oxygen species. Pancreatic cancer cells have high levels of reactive oxygen species but manage to avoid ferroptosis by importing extracellular cysteine. Studying mice bearing pancreatic tumors, Badgley <jats:italic>et al.</jats:italic> found that administration of a drug inhibiting cysteine import induced tumor-selective ferroptosis and inhibited tumor growth. Further work will be required to determine whether this therapeutic strategy will be effective in human pancreatic cancer, a tumor type for which new treatments are urgently needed. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6486" page="85" related-article-type="in-this-issue" vol="368" xlink:href="10.1126/science.aaw9872">85</jats:related-article> </jats:p>

<jats:title>How to read the face of a mouse</jats:title> <jats:p> The neuroscientific investigation of emotions is hindered by a lack of rapid and precise readouts of emotion states in model organisms. Dolensek <jats:italic>et al.</jats:italic> identified facial expressions as innate and sensitive reflections of the internal emotion state in mice (see the Perspective by Girard and Bellone). Mouse facial expressions evoked by diverse stimuli could be classified into emotionlike categories, similar to basic emotions in humans. Machine-learning algorithms categorized mouse facial expressions objectively and quantitatively at millisecond time scales. Intensity, value, and persistence of subjective emotion states could thus be decoded in individual animals. Combining facial expression analysis with two-photon calcium imaging allowed the identification of single neurons whose activity closely correlated with specific facial expressions in the insular cortex, a brain region implicated in affective experiences in humans. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6486" page="89" related-article-type="in-this-issue" vol="368" xlink:href="10.1126/science.aaz9468">89</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6486" page="33" related-article-type="in-this-issue" vol="368" xlink:href="10.1126/science.abb2796">33</jats:related-article> </jats:p>