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Single-chain heteropolymers transport protons selectively and rapidly 期刊论文
NATURE, 2020, 577 (7789) : 216-+
作者:  Jiang, Tao;  Hall, Aaron;  Eres, Marco;  Hemmatian, Zahra;  Qiao, Baofu;  Zhou, Yun;  Ruan, Zhiyuan;  Couse, Andrew D.;  Heller, William T.;  Huang, Haiyan;  de la Cruz, Monica Olvera;  Rolandi, Marco;  Xu, Ting
收藏  |  浏览/下载:9/0  |  提交时间:2020/07/03

Precise protein sequencing and folding are believed to generate the structure and chemical diversity of natural channels(1,2), both of which are essential to synthetically achieve proton transport performance comparable to that seen in natural systems. Geometrically defined channels have been fabricated using peptides, DNAs, carbon nanotubes, sequence-defined polymers and organic frameworks(3-13). However, none of these channels rivals the performance observed in their natural counterparts. Here we show that without forming an atomically structured channel, four-monomer-based random heteropolymers (RHPs)(14) can mimic membrane proteins and exhibit selective proton transport across lipid bilayers at a rate similar to those of natural proton channels. Statistical control over the monomer distribution in an RHP leads to segmental heterogeneity in hydrophobicity, which facilitates the insertion of single RHPs into the lipid bilayers. It also results in bilayer-spanning segments containing polar monomers that promote the formation of hydrogen-bonded chains(15,16) for proton transport. Our study demonstrates the importance of the adaptability that is enabled by statistical similarity among RHP chains and of the modularity provided by the chemical diversity of monomers, to achieve uniform behaviour in heterogeneous systems. Our results also validate statistical randomness as an unexplored approach to realize protein-like behaviour at the single-polymer-chain level in a predictable manner.


  
Monumental architecture at Aguada Fenix and the rise of Maya civilization 期刊论文
NATURE, 2020
作者:  Bedding, Timothy R.;  Murphy, Simon J.;  Hey, Daniel R.;  Huber, Daniel;  Li, Tanda;  Smalley, Barry;  Stello, Dennis;  White, Timothy R.;  Ball, Warrick H.;  Chaplin, William J.;  Colman, Isabel L.;  Fuller, Jim;  Gaidos, Eric;  Harbeck, Daniel R.;  Hermes, J. J.;  Holdsworth, Daniel L.;  Li, Gang;  Li, Yaguang;  Mann, Andrew W.;  Reese, Daniel R.;  Sekaran, Sanjay;  Yu, Jie;  Antoci, Victoria;  Bergmann, Christoph;  Brown, Timothy M.;  Howard, Andrew W.;  Ireland, Michael J.;  Isaacson, Howard;  Jenkins, Jon M.;  Kjeldsen, Hans;  McCully, Curtis;  Rabus, Markus;  Rains, Adam D.;  Ricker, George R.;  Tinney, Christopher G.;  Vanderspek, Roland K.
收藏  |  浏览/下载:30/0  |  提交时间:2020/07/03

Archaeologists have traditionally thought that the development of Maya civilization was gradual, assuming that small villages began to emerge during the Middle Preclassic period (1000-350 bc  dates are calibrated throughout) along with the use of ceramics and the adoption of sedentism(1). Recent finds of early ceremonial complexes are beginning to challenge this model. Here we describe an airborne lidar survey and excavations of the previously unknown site of Aguada Fenix (Tabasco, Mexico) with an artificial plateau, which measures 1,400 m in length and 10 to 15 m in height and has 9 causeways radiating out from it. We dated this construction to between 1000 and 800 bc using a Bayesian analysis of radiocarbon dates. To our knowledge, this is the oldest monumental construction ever found in the Maya area and the largest in the entire pre-Hispanic history of the region. Although the site exhibits some similarities to the earlier Olmec centre of San Lorenzo, the community of Aguada Fenix probably did not have marked social inequality comparable to that of San Lorenzo. Aguada Fenix and other ceremonial complexes of the same period suggest the importance of communal work in the initial development of Maya civilization.


Lidar survey of the Maya lowlands uncovers the monumental site of Aguada Fenix, which dates to around 1000-800 bc and points to the role of communal construction in the development of Maya civilization.


  
Highly porous nature of a primitive asteroid revealed by thermal imaging 期刊论文
NATURE, 2020, 579 (7800) : 518-522
作者:  Quinn, Robert A.;  Melnik, Alexey, V;  Vrbanac, Alison;  Fu, Ting;  Patras, Kathryn A.;  Christy, Mitchell P.;  Bodai, Zsolt;  Belda-Ferre, Pedro;  Tripathi, Anupriya;  Chung, Lawton K.;  Downes, Michael;  Welch, Ryan D.;  Quinn, Melissa;  Humphrey, Greg;  Panitchpakdi, Morgan;  Weldon, Kelly C.;  Aksenov, Alexander;  da Silva, Ricardo;  Avila-Pacheco, Julian;  Clish, Clary;  Bae, Sena;  Mallick, Himel;  Franzosa, Eric A.;  Lloyd-Price, Jason;  Bussell, Robert;  Thron, Taren;  Nelson, Andrew T.;  Wang, Mingxun;  Leszczynski, Eric;  Vargas, Fernando;  Gauglitz, Julia M.;  Meehan, Michael J.;  Gentry, Emily;  Arthur, Timothy D.;  Komor, Alexis C.;  Poulsen, Orit;  Boland, Brigid S.;  Chang, John T.;  Sandborn, William J.;  Lim, Meerana;  Garg, Neha;  Lumeng, Julie C.;  Xavier, Ramnik J.;  Kazmierczak, Barbara, I;  Jain, Ruchi;  Egan, Marie;  Rhee, Kyung E.;  Ferguson, David;  Raffatellu, Manuela;  Vlamakis, Hera;  Haddad, Gabriel G.;  Siegel, Dionicio;  Huttenhower, Curtis;  Mazmanian, Sarkis K.;  Evans, Ronald M.;  Nizet, Victor;  Knight, Rob;  Dorrestein, Pieter C.
收藏  |  浏览/下载:49/0  |  提交时间:2020/05/13

Carbonaceous (C-type) asteroids(1) are relics of the early Solar System that have preserved primitive materials since their formation approximately 4.6 billion years ago. They are probably analogues of carbonaceous chondrites(2,3) and are essential for understanding planetary formation processes. However, their physical properties remain poorly known because carbonaceous chondrite meteoroids tend not to survive entry to Earth'  s atmosphere. Here we report on global one-rotation thermographic images of the C-type asteroid 162173 Ryugu, taken by the thermal infrared imager (TIR)(4) onboard the spacecraft Hayabusa2(5), indicating that the asteroid'  s boulders and their surroundings have similar temperatures, with a derived thermal inertia of about 300 J m(-2) s(-0.5) K-1 (300 tiu). Contrary to predictions that the surface consists of regolith and dense boulders, this low thermal inertia suggests that the boulders are more porous than typical carbonaceous chondrites(6) and that their surroundings are covered with porous fragments more than 10 centimetres in diameter. Close-up thermal images confirm the presence of such porous fragments and the flat diurnal temperature profiles suggest a strong surface roughness effect(7,8). We also observed in the close-up thermal images boulders that are colder during the day, with thermal inertia exceeding 600 tiu, corresponding to dense boulders similar to typical carbonaceous chondrites(6). These results constrain the formation history of Ryugu: the asteroid must be a rubble pile formed from impact fragments of a parent body with microporosity(9) of approximately 30 to 50 per cent that experienced a low degree of consolidation. The dense boulders might have originated from the consolidated innermost region or they may have an exogenic origin. This high-porosity asteroid may link cosmic fluffy dust to dense celestial bodies(10).


Thermal imaging data obtained from the spacecraft Hayabusa2 reveal that the carbonaceous asteroid 162173 Ryugu is an object of unusually high porosity.


  
An intestinal zinc sensor regulates food intake and developmental growth 期刊论文
NATURE, 2020, 580 (7802) : 263-+
作者:  Wu, Thomas D.;  39;Gorman, William E.
收藏  |  浏览/下载:14/0  |  提交时间:2020/07/03

Hodor, an intestinal zinc-gated chloride channel, controls systemic growth in Drosophila by promoting food intake and by modulating Tor signalling and lysosomal homeostasis within enterocytes.


In cells, organs and whole organisms, nutrient sensing is key to maintaining homeostasis and adapting to a fluctuating environment(1). In many animals, nutrient sensors are found within the enteroendocrine cells of the digestive system  however, less is known about nutrient sensing in their cellular siblings, the absorptive enterocytes(1). Here we use a genetic screen in Drosophila melanogaster to identify Hodor, an ionotropic receptor in enterocytes that sustains larval development, particularly in nutrient-scarce conditions. Experiments in Xenopus oocytes and flies indicate that Hodor is a pH-sensitive, zinc-gated chloride channel that mediates a previously unrecognized dietary preference for zinc. Hodor controls systemic growth from a subset of enterocytes-interstitial cells-by promoting food intake and insulin/IGF signalling. Although Hodor sustains gut luminal acidity and restrains microbial loads, its effect on systemic growth results from the modulation of Tor signalling and lysosomal homeostasis within interstitial cells. Hodor-like genes are insect-specific, and may represent targets for the control of disease vectors. Indeed, CRISPR-Cas9 genome editing revealed that the single hodor orthologue in Anopheles gambiae is an essential gene. Our findings highlight the need to consider the instructive contributions of metals-and, more generally, micronutrients-to energy homeostasis.


  
gamma delta T cells and adipocyte IL-17RC control fat innervation and thermogenesis 期刊论文
NATURE, 2020, 578 (7796) : 610-+
作者:  Staus, Dean P.;  Hu, Hongli;  Robertson, Michael J.;  Kleinhenz, Alissa L. W.;  Wingler, Laura M.;  Capel, William D.;  Latorraca, Naomi R.;  Lefkowitz, Robert J.;  Skiniotis, Georgios
收藏  |  浏览/下载:42/0  |  提交时间:2020/07/03

V gamma 6(+) V delta 1(+) gamma delta T cells control tolerance to cold by activating adipocyte IL-17RC and promoting sympathetic innervation of thermogenic adipose tissue in mice.


The sympathetic nervous system innervates peripheral organs to regulate their function and maintain homeostasis, whereas target cells also produce neurotrophic factors to promote sympathetic innervation(1,2). The molecular basis of this bi-directional communication remains to be fully determined. Here we use thermogenic adipose tissue from mice as a model system to show that T cells, specifically gamma delta T cells, have a crucial role in promoting sympathetic innervation, at least in part by driving the expression of TGF beta 1 in parenchymal cells via the IL-17 receptor C (IL-17RC). Ablation of IL-17RC specifically in adipose tissue reduces expression of TGF beta 1 in adipocytes, impairs local sympathetic innervation and causes obesity and other metabolic phenotypes that are consistent with defective thermogenesis  innervation can be fully rescued by restoring TGF beta 1 expression. Ablating gamma delta tau cells and the IL-17RC signalling pathway also impairs sympathetic innervation in other tissues such as salivary glands. These findings demonstrate coordination between T cells and parenchymal cells to regulate sympathetic innervation.


  
DNA clamp function of the monoubiquitinated Fanconi anaemia ID complex 期刊论文
NATURE, 2020, 580 (7802) : 278-+
作者:  Wu, Thomas D.;  39;Gorman, William E.
收藏  |  浏览/下载:8/0  |  提交时间:2020/07/03

The ID complex, involving the proteins FANCI and FANCD2, is required for the repair of DNA interstrand crosslinks (ICL) and related lesions(1). These proteins are mutated in Fanconi anaemia, a disease in which patients are predisposed to cancer. The Fanconi anaemia pathway of ICL repair is activated when a replication fork stalls at an ICL2  this triggers monoubiquitination of the ID complex, in which one ubiquitin molecule is conjugated to each of FANCI and FANCD2. Monoubiquitination of ID is essential for ICL repair by excision, translesion synthesis and homologous recombination  however, its function remains unknown(1,3). Here we report a cryo-electron microscopy structure of the monoubiquitinated human ID complex bound to DNA, and reveal that it forms a closed ring that encircles the DNA. By comparison with the structure of the non-ubiquitinated ID complex bound to ICL DNA-which we also report here-we show that monoubiquitination triggers a complete rearrangement of the open, trough-like ID structure through the ubiquitin of one protomer binding to the other protomer in a reciprocal fashion. These structures-together with biochemical data-indicate that the monoubiquitinated ID complex loses its preference for ICL and related branched DNA structures, and becomes a sliding DNA clamp that can coordinate the subsequent repair reactions. Our findings also reveal how monoubiquitination in general can induce an alternative protein structure with a new function.


Cryo-EM structures of the FANCI-FANCD2 complex bound to DNA reveal that monoubiquitination triggers structural changes that enable the complex to function as a sliding DNA clamp and coordinate the repair of DNA interstrand crosslinks.


  
Experimental demonstration of memory-enhanced quantum communication 期刊论文
NATURE, 2020
作者:  Quinn, Robert A.;  Melnik, Alexey, V;  Vrbanac, Alison;  Fu, Ting;  Patras, Kathryn A.;  Christy, Mitchell P.;  Bodai, Zsolt;  Belda-Ferre, Pedro;  Tripathi, Anupriya;  Chung, Lawton K.;  Downes, Michael;  Welch, Ryan D.;  Quinn, Melissa;  Humphrey, Greg;  Panitchpakdi, Morgan;  Weldon, Kelly C.;  Aksenov, Alexander;  da Silva, Ricardo;  Avila-Pacheco, Julian;  Clish, Clary;  Bae, Sena;  Mallick, Himel;  Franzosa, Eric A.;  Lloyd-Price, Jason;  Bussell, Robert;  Thron, Taren;  Nelson, Andrew T.;  Wang, Mingxun;  Leszczynski, Eric;  Vargas, Fernando;  Gauglitz, Julia M.;  Meehan, Michael J.;  Gentry, Emily;  Arthur, Timothy D.;  Komor, Alexis C.;  Poulsen, Orit;  Boland, Brigid S.;  Chang, John T.;  Sandborn, William J.;  Lim, Meerana;  Garg, Neha;  Lumeng, Julie C.;  Xavier, Ramnik J.;  Kazmierczak, Barbara, I;  Jain, Ruchi;  Egan, Marie;  Rhee, Kyung E.;  Ferguson, David;  Raffatellu, Manuela;  Vlamakis, Hera;  Haddad, Gabriel G.;  Siegel, Dionicio;  Huttenhower, Curtis;  Mazmanian, Sarkis K.;  Evans, Ronald M.;  Nizet, Victor;  Knight, Rob;  Dorrestein, Pieter C.
收藏  |  浏览/下载:36/0  |  提交时间:2020/07/03

The ability to communicate quantum information over long distances is of central importance in quantum science and engineering(1). Although some applications of quantum communication such as secure quantum key distribution(2,3) are already being successfully deployed(4-7), their range is currently limited by photon losses and cannot be extended using straightforward measure-and-repeat strategies without compromising unconditional security(8). Alternatively, quantum repeaters(9), which utilize intermediate quantum memory nodes and error correction techniques, can extend the range of quantum channels. However, their implementation remains an outstanding challenge(10-16), requiring a combination of efficient and high-fidelity quantum memories, gate operations, and measurements. Here we use a single solid-state spin memory integrated in a nanophotonic diamond resonator(17-19) to implement asynchronous photonic Bell-state measurements, which are a key component of quantum repeaters. In a proof-of-principle experiment, we demonstrate high-fidelity operation that effectively enables quantum communication at a rate that surpasses the ideal loss-equivalent direct-transmission method while operating at megahertz clock speeds. These results represent a crucial step towards practical quantum repeaters and large-scale quantum networks(20,21).


A solid-state spin memory is used to demonstrate quantum repeater functionality, which has the potential to overcome photon losses involved in long-distance transmission of quantum information.


  
Direct thermal neutron detection by the 2D semiconductor (LiInP2Se6)-Li-6 (2020) (vol 577, pg 346, 2020) 期刊论文
NATURE, 2020, 579 (7799) : E9-E9
作者:  Groen, Simon C.;  Calic, Irina;  Joly-Lopez, Zoe;  Platts, Adrian E.;  Choi, Jae Young;  Natividad, Mignon;  Dorph, Katherine;  Mauck, William M., III;  Bracken, Bernadette;  Cabral, Carlo Leo U.;  Kumar, Arvind;  Torres, Rolando O.;  Satija, Rahul;  Vergara, Georgina;  Henry, Amelia;  Franks, Steven J.;  Purugganan, Michael D.
收藏  |  浏览/下载:26/0  |  提交时间:2020/07/03

An amendment to this paper has been published and can be accessed via a link at the top of the paper.


  
Streamflow response to forest management 期刊论文
NATURE, 2020, 578 (7794) : E12-E15
作者:  Jiang, Tao;  Hall, Aaron;  Eres, Marco;  Hemmatian, Zahra;  Qiao, Baofu;  Zhou, Yun;  Ruan, Zhiyuan;  Couse, Andrew D.;  Heller, William T.;  Huang, Haiyan;  de la Cruz, Monica Olvera;  Rolandi, Marco;  Xu, Ting
收藏  |  浏览/下载:8/0  |  提交时间:2020/05/13
Investigation of the fine structure of antihydrogen 期刊论文
NATURE, 2020, 578 (7795) : 375-+
作者:  Zhang, Bing;  Ma, Sai;  Rachmin, Inbal;  He, Megan;  Baral, Pankaj;  Choi, Sekyu;  Goncalves, William A.;  Shwartz, Yulia;  Fast, Eva M.;  Su, Yiqun;  Zon, Leonard I.;  Regev, Aviv;  Buenrostro, Jason D.;  Cunha, Thiago M.;  Chiu, Isaac M.;  Fisher, David E.;  Hsu, Ya-Chieh
收藏  |  浏览/下载:25/0  |  提交时间:2020/07/03

At the historic Shelter Island Conference on the Foundations of Quantum Mechanics in 1947, Willis Lamb reported an unexpected feature in the fine structure of atomic hydrogen: a separation of the 2S(1/2) and 2P(1/2) states(1). The observation of this separation, now known as the Lamb shift, marked an important event in the evolution of modern physics, inspiring others to develop the theory of quantum electrodynamics(2-5). Quantum electrodynamics also describes antimatter, but it has only recently become possible to synthesize and trap atomic antimatter to probe its structure. Mirroring the historical development of quantum atomic physics in the twentieth century, modern measurements on anti-atoms represent a unique approach for testing quantum electrodynamics and the foundational symmetries of the standard model. Here we report measurements of the fine structure in the n = 2 states of antihydrogen, the antimatter counterpart of the hydrogen atom. Using optical excitation of the 1S-2P Lyman-alpha transitions in antihydrogen(6), we determine their frequencies in a magnetic field of 1 tesla to a precision of 16 parts per billion. Assuming the standard Zeeman and hyperfine interactions, we infer the zero-field fine-structure splitting (2P(1/2)-2P(3/2)) in antihydrogen. The resulting value is consistent with the predictions of quantum electrodynamics to a precision of 2 per cent. Using our previously measured value of the 1S-2S transition frequency(6,7), we find that the classic Lamb shift in antihydrogen (2S(1/2)-2P(1/2) splitting at zero field) is consistent with theory at a level of 11 per cent. Our observations represent an important step towards precision measurements of the fine structure and the Lamb shift in the antihydrogen spectrum as tests of the charge-parity-time symmetry(8) and towards the determination of other fundamental quantities, such as the antiproton charge radius(9,10), in this antimatter system.


Precision measurements of the 1S-2P transition in antihydrogen that take into account the standard Zeeman and hyperfine effects confirm the predictions of quantum electrodynamics.