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Light limitation regulates the response of autumn terrestrial carbon uptake to warming 期刊论文
NATURE CLIMATE CHANGE, 2020
作者:  Zhang, Yao;  Commane, Roisin;  Zhou, Sha;  Williams, A. Park;  Gentine, Pierre
收藏  |  浏览/下载:15/0  |  提交时间:2020/07/09
Fire and climate change: conserving seasonally dry forests is still possible 期刊论文
FRONTIERS IN ECOLOGY AND THE ENVIRONMENT, 2020
作者:  Stephens, Scott L.;  Westerling, A. LeRoy;  Hurteau, Matthew D.;  Peery, M. Zachariah;  Schultz, Courtney A.;  Thompson, Sally
收藏  |  浏览/下载:10/0  |  提交时间:2020/08/18
Fire and climate change: conserving seasonally dry forests is still possible 期刊论文
FRONTIERS IN ECOLOGY AND THE ENVIRONMENT, 2020
作者:  Stephens, Scott L.;  Westerling, A. LeRoy;  Hurteau, Matthew D.;  Peery, M. Zachariah;  Schultz, Courtney A.;  Thompson, Sally
收藏  |  浏览/下载:8/0  |  提交时间:2020/07/02
Carbon intensity of global crude oil refining and mitigation potential 期刊论文
NATURE CLIMATE CHANGE, 2020, 10 (6) : 526-+
作者:  Jing, Liang;  El-Houjeiri, Hassan M.;  Monfort, Jean-Christophe;  Brandt, Adam R.;  Masnadi, Mohammad S.;  Gordon, Deborah;  Bergerson, Joule A.
收藏  |  浏览/下载:18/0  |  提交时间:2020/06/09
Circumpolar projections of Antarctic krill growth potential 期刊论文
NATURE CLIMATE CHANGE, 2020, 10 (6) : 568-+
作者:  Veytia, Devi;  Corney, Stuart;  Meiners, Klaus M.;  Kawaguchi, So;  Murphy, Eugene J.;  Bestley, Sophie
收藏  |  浏览/下载:6/0  |  提交时间:2020/05/20
A trait-based understanding of wood decomposition by fungi 期刊论文
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 2020, 117 (21) : 11551-11558
作者:  Lustenhouwer, Nicky;  Maynard, Daniel S.;  Bradford, Mark A.;  Lindner, Daniel L.;  Oberle, Brad;  Zanne, Amy E.;  Crowther, Thomas W.
收藏  |  浏览/下载:17/0  |  提交时间:2020/05/20
fungal traits  wood decomposition  carbon cycle  functional biogeography  decay rate  
IL-17a promotes sociability in mouse models of neurodevelopmental disorders 期刊论文
NATURE, 2020, 577 (7789) : 249-+
作者:  Reed, Michael Douglas;  Yim, Yeong Shin;  Wimmer, Ralf D.;  Kim, Hyunju;  Ryu, Changhyeon;  Welch, Gwyneth Margaret;  Andina, Matias;  King, Hunter Oren;  Waisman, Ari;  Halassa, Michael M.;  Huh, Jun R.;  Choi, Gloria B.
收藏  |  浏览/下载:11/0  |  提交时间:2020/07/03

A subset of children with autism spectrum disorder appear to show an improvement in their behavioural symptoms during the course of a fever, a sign of systemic inflammation(1,2). Here we elucidate the molecular and neural mechanisms that underlie the beneficial effects of inflammation on social behaviour deficits in mice. We compared an environmental model of neurodevelopmental disorders in which mice were exposed to maternal immune activation (MIA) during embryogenesis(3,4) with mouse models that are genetically deficient for contactin-associated protein-like 2 (Cntnap2)(5), fragile X mental retardation-1 (Fmr1)(6) or Sh3 and multiple ankyrin repeat domains 3 (Shank3)(7). We establish that the social behaviour deficits in offspring exposed to MIA can be temporarily rescued by the inflammatory response elicited by the administration of lipopolysaccharide (LPS). This behavioural rescue was accompanied by a reduction in neuronal activity in the primary somatosensory cortex dysgranular zone (S1DZ), the hyperactivity of which was previously implicated in the manifestation of behavioural phenotypes associated with offspring exposed to MIA(8). By contrast, we did not observe an LPS-induced rescue of social deficits in the monogenic models. We demonstrate that the differences in responsiveness to the LPS treatment between the MIA and the monogenic models emerge from differences in the levels of cytokine production. LPS treatment in monogenic mutant mice did not induce amounts of interleukin-17a (IL-17a) comparable to those induced in MIA offspring  bypassing this difference by directly delivering IL-17a into S1DZ was sufficient to promote sociability in monogenic mutant mice as well as in MIA offspring. Conversely, abrogating the expression of IL-17 receptor subunit a (IL-17Ra) in the neurons of the S1DZ eliminated the ability of LPS to reverse the sociability phenotypes in MIA offspring. Our data support a neuroimmune mechanism that underlies neurodevelopmental disorders in which the production of IL-17a during inflammation can ameliorate the expression of social behaviour deficits by directly affecting neuronal activity in the central nervous system.


  
A metabolic pathway for bile acid dehydroxylation by the gut microbiome 期刊论文
NATURE, 2020
作者:  Zhong, Miao;  Tran, Kevin;  Min, Yimeng;  Wang, Chuanhao;  Wang, Ziyun;  Dinh, Cao-Thang;  De Luna, Phil;  Yu, Zongqian;  Rasouli, Armin Sedighian;  Brodersen, Peter;  Sun, Song;  Voznyy, Oleksandr;  Tan, Chih-Shan;  Askerka, Mikhail;  Che, Fanglin;  Liu, Min;  Seifitokaldani, Ali;  Pang, Yuanjie;  Lo, Shen-Chuan;  Ip, Alexander;  Ulissi, Zachary;  Sargent, Edward H.
收藏  |  浏览/下载:14/0  |  提交时间:2020/07/03

The biosynthetic pathway that produces the secondary bile acids DCA and LCA in human gut microbes has been fully characterized, engineered into another bacterial host, and used to confer DCA production in germ-free mice-an important proof-of-principle for the engineering of gut microbial pathways.


The gut microbiota synthesize hundreds of molecules, many of which influence host physiology. Among the most abundant metabolites are the secondary bile acids deoxycholic acid (DCA) and lithocholic acid (LCA), which accumulate at concentrations of around 500 mu M and are known to block the growth ofClostridium difficile(1), promote hepatocellular carcinoma(2)and modulate host metabolism via the G-protein-coupled receptor TGR5 (ref.(3)). More broadly, DCA, LCA and their derivatives are major components of the recirculating pool of bile acids(4)  the size and composition of this pool are a target of therapies for primary biliary cholangitis and nonalcoholic steatohepatitis. Nonetheless, despite the clear impact of DCA and LCA on host physiology, an incomplete knowledge of their biosynthetic genes and a lack of genetic tools to enable modification of their native microbial producers limit our ability to modulate secondary bile acid levels in the host. Here we complete the pathway to DCA and LCA by assigning and characterizing enzymes for each of the steps in its reductive arm, revealing a strategy in which the A-B rings of the steroid core are transiently converted into an electron acceptor for two reductive steps carried out by Fe-S flavoenzymes. Using anaerobic in vitro reconstitution, we establish that a set of six enzymes is necessary and sufficient for the eight-step conversion of cholic acid to DCA. We then engineer the pathway intoClostridium sporogenes, conferring production of DCA and LCA on a nonproducing commensal and demonstrating that a microbiome-derived pathway can be expressed and controlled heterologously. These data establish a complete pathway to two central components of the bile acid pool.


  
The fate of carbon in a mature forest under carbon dioxide enrichment 期刊论文
NATURE, 2020, 580 (7802) : 227-+
作者:  Sun, P. Z.;  Yang, Q.;  Kuang, W. J.;  Stebunov, Y. V.;  Xiong, W. Q.;  Yu, J.;  Nair, R. R.;  Katsnelson, M. I.;  Yuan, S. J.;  Grigorieva, I. V.;  Lozada-Hidalgo, M.;  Wang, F. C.;  Geim, A. K.
收藏  |  浏览/下载:70/0  |  提交时间:2020/05/13

Carbon dioxide enrichment of a mature forest resulted in the emission of the excess carbon back into the atmosphere via enhanced ecosystem respiration, suggesting that mature forests may be limited in their capacity to mitigate climate change.


Atmospheric carbon dioxide enrichment (eCO(2)) can enhance plant carbon uptake and growth(1-5), thereby providing an important negative feedback to climate change by slowing the rate of increase of the atmospheric CO2 concentration(6). Although evidence gathered from young aggrading forests has generally indicated a strong CO2 fertilization effect on biomass growth(3-5), it is unclear whether mature forests respond to eCO(2) in a similar way. In mature trees and forest stands(7-10), photosynthetic uptake has been found to increase under eCO(2) without any apparent accompanying growth response, leaving the fate of additional carbon fixed under eCO(2) unclear(4,5,7-11). Here using data from the first ecosystem-scale Free-Air CO2 Enrichment (FACE) experiment in a mature forest, we constructed a comprehensive ecosystem carbon budget to track the fate of carbon as the forest responded to four years of eCO(2) exposure. We show that, although the eCO(2) treatment of +150 parts per million (+38 per cent) above ambient levels induced a 12 per cent (+247 grams of carbon per square metre per year) increase in carbon uptake through gross primary production, this additional carbon uptake did not lead to increased carbon sequestration at the ecosystem level. Instead, the majority of the extra carbon was emitted back into the atmosphere via several respiratory fluxes, with increased soil respiration alone accounting for half of the total uptake surplus. Our results call into question the predominant thinking that the capacity of forests to act as carbon sinks will be generally enhanced under eCO(2), and challenge the efficacy of climate mitigation strategies that rely on ubiquitous CO2 fertilization as a driver of increased carbon sinks in global forests.


  
Leaf size of woody dicots predicts ecosystem primary productivity 期刊论文
ECOLOGY LETTERS, 2020, 23 (6) : 1003-1013
作者:  Li, Yaoqi;  Reich, Peter B.;  Schmid, Bernhard;  Shrestha, Nawal;  Feng, Xiao;  Lyu, Tong;  Maitner, Brian S.;  Xu, Xiaoting;  Li, Yichao;  Zou, Dongting;  Tan, Zheng-Hong;  Su, Xiangyan;  Tang, Zhiyao;  Guo, Qinghua;  Feng, Xiaojuan;  Enquist, Brian J.;  Wang, Zhiheng
收藏  |  浏览/下载:13/0  |  提交时间:2020/05/13
Annual evapotranspiration  China  community mean leaf size  large-scale eco-evolutionary patterns  leaf area index  North America  palaeo-primary productivity  plant functional traits