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国际智库为中国促进气候-贸易协同发展提出建议 快报文章
气候变化快报，2022年第21期
作者:  裴惠娟
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China  Climate-trade Nexus  International Role  
IEA分析CCUS在低碳电力系统中的作用 快报文章
气候变化快报，2020年第15期
作者:  董利苹
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Role  CCUS  Low-carbon Power Systems  
Revealing enigmatic mucus structures in the deep sea using DeepPIV 期刊论文
NATURE, 2020, 583 (7814) : 78-+
作者:  Nguyen, Ngoc Uyen Nhi;  Canseco, Diana C.;  Xiao, Feng;  Nakada, Yuji;  Li, Shujuan;  Lam, Nicholas T.;  Muralidhar, Shalini A.;  Savla, Jainy J.;  Hill, Joseph A.;  Le, Victor;  Zidan, Kareem A.;  El-Feky, Hamed W.;  Wang, Zhaoning;  Ahmed, Mahmoud Salama;  Hubbi, Maimon E.;  Menendez-Montes, Ivan
收藏  |  浏览/下载：13/0  |  提交时间：2020/06/09

Advanced deep-sea imaging tools yield insights into the structure and function of mucus filtration houses built by midwater giant larvaceans.


Many animals build complex structures to aid in their survival, but very few are built exclusively from materials that animals create (1,2). In the midwaters of the ocean, mucoid structures are readily secreted by numerous animals, and serve many vital functions(3,4). However, little is known about these mucoid structures owing to the challenges of observing them in the deep sea. Among these mucoid forms, the '  houses'  of larvaceans are marvels of nature(5), and in the ocean twilight zone giant larvaceans secrete and build mucus filtering structures that can reach diameters of more than 1 m(6). Here we describe in situ laser-imaging technology(7) that reconstructs three-dimensional models of mucus forms. The models provide high-resolution views of giant larvacean houses and elucidate the role that house structure has in food capture and predator avoidance. Now that tools exist to study mucus structures found throughout the ocean, we can shed light on some of nature'  s most complex forms.


  
Cortical pattern generation during dexterous movement is input-driven 期刊论文
NATURE, 2020, 577 (7790) : 386-+
作者:  Cyranoski, David
收藏  |  浏览/下载：9/0  |  提交时间：2020/07/03

The motor cortex controls skilled arm movement by sending temporal patterns of activity to lower motor centres(1). Local cortical dynamics are thought to shape these patterns throughout movement execution(2-4). External inputs have been implicated in setting the initial state of the motor cortex(5,6), but they may also have a pattern-generating role. Here we dissect the contribution of local dynamics and inputs to cortical pattern generation during a prehension task in mice. Perturbing cortex to an aberrant state prevented movement initiation, but after the perturbation was released, cortex either bypassed the normal initial state and immediately generated the pattern that controls reaching or failed to generate this pattern. The difference in these two outcomes was probably a result of external inputs. We directly investigated the role of inputs by inactivating the thalamus  this perturbed cortical activity and disrupted limb kinematics at any stage of the movement. Activation of thalamocortical axon terminals at different frequencies disrupted cortical activity and arm movement in a graded manner. Simultaneous recordings revealed that both thalamic activity and the current state of cortex predicted changes in cortical activity. Thus, the pattern generator for dexterous arm movement is distributed across multiple, strongly interacting brain regions.


  
Patterns and trends of Northern Hemisphere snow mass from 1980 to 2018 期刊论文
NATURE, 2020, 581 (7808) : 294-+
作者:  Ibrahim, Nizar;  Maganuco, Simone;  Dal Sasso, Cristiano;  Fabbri, Matteo;  Auditore, Marco;  Bindellini, Gabriele;  Martill, David M.;  Zouhri, Samir;  Mattarelli, Diego A.;  Unwin, David M.;  Wiemann, Jasmina;  Bonadonna, Davide;  Amane, Ayoub;  Jakubczak, Juliana;  Joger, Ulrich;  Lauder, George V.;  Pierce, Stephanie E.
收藏  |  浏览/下载：18/0  |  提交时间：2020/05/25

Warming surface temperatures have driven a substantial reduction in the extent and duration of Northern Hemisphere snow cover(1-3). These changes in snow cover affect Earth'  s climate system via the surface energy budget, and influence freshwater resources across a large proportion of the Northern Hemisphere(4-6). In contrast to snow extent, reliable quantitative knowledge on seasonal snow mass and its trend is lacking(7-9). Here we use the new GlobSnow 3.0 dataset to show that the 1980-2018 annual maximum snow mass in the Northern Hemisphere was, on average, 3,062 +/- 35 billion tonnes (gigatonnes). Our quantification is for March (the month that most closely corresponds to peak snow mass), covers non-alpine regions above 40 degrees N and, crucially, includes a bias correction based on in-field snow observations. We compare our GlobSnow 3.0 estimates with three independent estimates of snow mass, each with and without the bias correction. Across the four datasets, the bias correction decreased the range from 2,433-3,380 gigatonnes (mean 2,867) to 2,846-3,062 gigatonnes (mean 2,938)-a reduction in uncertainty from 33% to 7.4%. On the basis of our bias-corrected GlobSnow 3.0 estimates, we find different continental trends over the 39-year satellite record. For example, snow mass decreased by 46 gigatonnes per decade across North America but had a negligible trend across Eurasia  both continents exhibit high regional variability. Our results enable a better estimation of the role of seasonal snow mass in Earth'  s energy, water and carbon budgets.


Applying a bias correction to a state-of-the-art dataset covering non-alpine regions of the Northern Hemisphere and to three other datasets yields a more constrained quantification of snow mass in March from 1980 to 2018.


  
DNA-repair enzyme turns to translation 期刊论文
NATURE, 2020, 579 (7798) : 198-199
作者:  Bian, Zhilei;  Gong, Yandong;  Huang, Tao;  Lee, Christopher Z. W.;  Bian, Lihong;  Bai, Zhijie;  Shi, Hui;  Zeng, Yang;  Liu, Chen;  He, Jian;  Zhou, Jie;  Li, Xianlong;  Li, Zongcheng;  Ni, Yanli;  Ma, Chunyu;  Cui, Lei;  Zhang, Rui;  Chan, Jerry K. Y.;  Ng, Lai Guan;  Lan, Yu;  Ginhoux, Florent;  Liu, Bing
收藏  |  浏览/下载：13/0  |  提交时间：2020/07/03

A key DNA-repair enzyme has a surprising role during the early steps in the assembly of ribosomes - the molecular machines that translate the genetic code into protein.


  
RGF1 controls root meristem size through ROS signalling 期刊论文
NATURE, 2020, 577 (7788) : 85-+
作者:  Yamada, Masashi;  Han, Xinwei;  Benfey, Philip N.
收藏  |  浏览/下载：11/0  |  提交时间：2020/07/03

The stem cell niche and the size of the root meristem in plants are maintained by intercellular interactions and signalling networks involving a peptide hormone, root meristem growth factor 1 (RGF1)(1). Understanding how RGF1 regulates the development of the root meristem is essential for understanding stem cell function. Although five receptors for RGF1 have been identified(2-4), the downstream signalling mechanism remains unknown. Here we report a series of signalling events that follow RGF1 activity. We find that the RGF1-receptor pathway controls the distribution of reactive oxygen species (ROS) along the developmental zones of the Arabidopsis root. We identify a previously uncharacterized transcription factor, RGF1-INDUCIBLE TRANSCRIPTION FACTOR 1 (RITF1), that has a central role in mediating RGF1 signalling. Manipulating RITF1 expression leads to the redistribution of ROS along the root developmental zones. Changes in ROS distribution in turn enhance the stability of the PLETHORA2 protein, a master regulator of root stem cells. Our results thus clearly depict a signalling cascade that is initiated by RGF1, linking this peptide to mechanisms that regulate ROS.


  
Structure of nevanimibe-bound tetrameric human ACAT1 期刊论文
NATURE, 2020, 581 (7808) : 339-U214
作者:  Ma, Xiyu;  Claus, Lucas A. N.;  Leslie, Michelle E.;  Tao, Kai;  Wu, Zhiping;  Liu, Jun;  Yu, Xiao;  Li, Bo;  Zhou, Jinggeng;  Savatin, Daniel V.;  Peng, Junmin;  Tyler, Brett M.;  Heese, Antje;  Russinova, Eugenia;  He, Ping;  Shan, Libo
收藏  |  浏览/下载：29/0  |  提交时间：2020/07/03

The structure of human ACAT1 in complex with the inhibitor nevanimibe is resolved by cryo-electron microscopy.


Cholesterol is an essential component of mammalian cell membranes, constituting up to 50% of plasma membrane lipids. By contrast, it accounts for only 5% of lipids in the endoplasmic reticulum (ER)(1). The ER enzyme sterol O-acyltransferase 1 (also named acyl-coenzyme A:cholesterol acyltransferase, ACAT1) transfers a long-chain fatty acid to cholesterol to form cholesteryl esters that coalesce into cytosolic lipid droplets. Under conditions of cholesterol overload, ACAT1 maintains the low cholesterol concentration of the ER and thereby has an essential role in cholesterol homeostasis(2,3). ACAT1 has also been implicated in Alzheimer'  s disease(4), atherosclerosis(5) and cancers(6). Here we report a cryo-electron microscopy structure of human ACAT1 in complex with nevanimibe(7), an inhibitor that is in clinical trials for the treatment of congenital adrenal hyperplasia. The ACAT1 holoenzyme is a tetramer that consists of two homodimers. Each monomer contains nine transmembrane helices (TMs), six of which (TM4-TM9) form a cavity that accommodates nevanimibe and an endogenous acyl-coenzyme A. This cavity also contains a histidine that has previously been identified as essential for catalytic activity(8). Our structural data and biochemical analyses provide a physical model to explain the process of cholesterol esterification, as well as details of the interaction between nevanimibe and ACAT1, which may help to accelerate the development of ACAT1 inhibitors to treat related diseases.


  
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.


  
Dynamic RNA acetylation revealed by quantitative cross-evolutionary mapping 期刊论文
NATURE, 2020, 583 (7817) : 638-+
作者:  Lin, Yiheng;  Leibrandt, David R.;  Leibfriedz, Dietrich;  Chou, Chin-wen
收藏  |  浏览/下载：27/0  |  提交时间：2020/07/03

A method termed ac(4)C-seq is introduced for the transcriptome-wide mapping of the RNA modificationN(4)-acetylcytidine, revealing widespread temperature-dependent acetylation that facilitates thermoadaptation in hyperthermophilic archaea.


N-4-acetylcytidine (ac(4)C) is an ancient and highly conserved RNA modification that is present on tRNA and rRNA and has recently been investigated in eukaryotic mRNA(1-3). However, the distribution, dynamics and functions of cytidine acetylation have yet to be fully elucidated. Here we report ac(4)C-seq, a chemical genomic method for the transcriptome-wide quantitative mapping of ac(4)C at single-nucleotide resolution. In human and yeast mRNAs, ac(4)C sites are not detected but can be induced-at a conserved sequence motif-via the ectopic overexpression of eukaryotic acetyltransferase complexes. By contrast, cross-evolutionary profiling revealed unprecedented levels of ac(4)C across hundreds of residues in rRNA, tRNA, non-coding RNA and mRNA from hyperthermophilic archaea. (AcC)-C-4 is markedly induced in response to increases in temperature, and acetyltransferase-deficient archaeal strains exhibit temperature-dependent growth defects. Visualization of wild-type and acetyltransferase-deficient archaeal ribosomes by cryo-electron microscopy provided structural insights into the temperature-dependent distribution of ac(4)C and its potential thermoadaptive role. Our studies quantitatively define the ac(4)C landscape, providing a technical and conceptual foundation for elucidating the role of this modification in biology and disease(4-6).