Catálogo de publicaciones - revistas

<jats:title>A tale of tadpole tail regeneration</jats:title> <jats:p> Some vertebrates, including some amphibians, show a remarkable, if sometimes restricted, ability to regenerate lost appendages. Aztekin <jats:italic>et al.</jats:italic> compared naturally occurring regeneration-competent and -incompetent <jats:italic>Xenopus laevis</jats:italic> tadpoles using single-cell messenger RNA sequencing. They identified regeneration-organizing cells (ROCs) that could coordinate tail regeneration. Relocation of ROCs from the body to the amputation plane enabled specialized wound epidermis formation and subsequent regeneration. ROCs simultaneously expressed many different ligands that can induce proliferation of different progenitor cell populations. Thus, by signaling to underlying progenitors, ROCs orchestrate the growth of a new appendage. </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="6441" page="653" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aav9996">653</jats:related-article> </jats:p>

<jats:title>Designed to respond</jats:title> <jats:p> Protein design has achieved success in finding sequences that fold to very stable target structures. Protein function, however, often requires conformational dynamics. Boyken <jats:italic>et al.</jats:italic> describe designed proteins that undergo conformational transitions in response to pH. They designed helical oligomers in which histidines are positioned in hydrogen-bond networks at the interfaces, with complimentary hydrophobic packing around the networks. Lowering the pH protonated the histidine, disrupting the oligomers. After endocytosis into low-pH compartments in cells, the designed proteins disrupted endosomal membranes. </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="6441" page="658" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aav7897">658</jats:related-article> </jats:p>

<jats:title>Bonding's outer limit</jats:title> <jats:p> In a Rydberg state, an atom has been very nearly, but not quite, ionized. This puts the electron relatively far from the nucleus, and two atoms in such a state can thus form a rather long-range bond. Hollerith <jats:italic>et al.</jats:italic> observed this phenomenon in fine detail by exciting pairs of ultracold rubidium atoms along the diagonal of an optical lattice. The authors resolved the vibrational state structure spectroscopically and showed that the Rydberg dimers manifested bond lengths exceeding 700 nanometers. </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="6441" page="664" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aaw4150">664</jats:related-article> </jats:p>

<jats:title>Dynamical refinement spots a difference</jats:title> <jats:p> For chiral molecules used in drugs, one isomer can have beneficial bioactivity, whereas the others are useless or even harmful. Determining the absolute configuration of molecules with chiral centers is often achieved through x-ray crystallography, but this requires relatively large crystals and high-quality data. Brázda <jats:italic>et al.</jats:italic> used electron diffraction to determine the absolute structure of an extremely radiation-sensitive crystal with micrometer dimensions (see the Perspective by Xu and Zou). In a strategy analogous to serial crystallography methods, many frames were combined to generate a complete dataset. Refinement incorporating dynamical effects differentiated the correct and incorrect molecular configuration. </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="6441" page="667" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aaw2560">667</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6441" page="632" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aax5385">632</jats:related-article> </jats:p>