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1. chinaXiv:201801.00773 [pdf]

Vertical distribution and storage of soil organic and inorganic carbon in a typical inland river basin, Northwest China

YANG Fan; HUANG Laiming; YANG Renmin; YANG Fei; LI Decheng; ZHAO Yuguo; YANG Jinling; LIU Feng; ZHANG Ganlin
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Soil Science

Knowledge of soil carbon (C) distribution and its relationship with the environment can improve our understanding of its biogeochemical cycling and help to establish sound regional models of C cycling. However, such knowledge is limited in environments with complex landscape configurations. In this study, we investigated the vertical distribution and storage of soil organic carbon (SOC) and soil inorganic carbon (SIC) in the 10 representative landscapes (alpine meadow, subalpine shrub and meadow, mountain grassland, mountain forest, typical steppe, desert steppe, Hexi Corridor oases cropland, Ruoshui River delta desert, Alxa Gobi desert, and sandy desert) with contrasting bioclimatic regimes in the Heihe River Basin, Northwest China. We also measured the 87Sr/86Sr ratio in soil carbonate to understand the sources of SIC because the ratio can be used as a proxy in calculating the contribution of pedogenic inorganic carbon (PIC) to total SIC. Our results showed that SOC contents generally decreased with increasing soil depth in all landscapes, while SIC contents exhibited more complicated variations along soil profiles in relation to pedogenic processes and parent materials at the various landscapes. There were significant differences of C stocks in the top meter among different landscapes, with SOC storage ranging from 0.82 kg C/m2 in sandy desert to 50.48 kg C/m2 in mountain forest and SIC storage ranging from 0.19 kg C/m2 in alpine meadow to 21.91 kg C/m2 in desert steppe. SIC contributed more than 75% of total C pool when SOC storage was lower than 10 kg C/m2, and the proportion of PIC to SIC was greater than 70% as calculated from Sr isotopic ratio, suggesting the critical role of PIC in the C budget of this region. The considerable variations of SOC and SIC in different landscapes were attributed to different pedogenic environments resulted from contrasting climatic regimes, parent materials and vegetation types. This study provides an evidence for a general trade-off pattern between SOC and SIC, showing the compensatory effects of environmental conditions (especially climate) on SOC and SIC formation in these landscapes. This is largely attributed to the fact that the overall decrease in temperature and increase in precipitation from arid deserts to alpine mountains simultaneously facilitate the accumulation of SOC and depletion of SIC.

submitted time 2018-01-29 From cooperative journals:《Journal of Arid Land》 Hits12569Downloads1386 Comment 1

2. chinaXiv:201605.01441 [pdf]

Phospho-selective mechanisms of arrestin conformations and functions revealed by unnatural amino acid incorporation and F-19-NMR

Yang, Fan; Li, Fa-Hui; Wang, Jiang-Yun; Yang, Fan; Li, Fa-Hui; Wang, Jiang-Yun; Yang, Fan; Yu, Xiao; Liu, Chuan; Qu, Chang-Xiu; Gong, Zheng; Liu, Hong-Da; He, Dong-Fang; Sun, Jin-Peng; Yang, Fan; Yu, Xiao; Liu, Chuan; Qu, Chang-Xiu; Gong, Zheng; Liu, Hong-Da
Subjects: Biology >> Biophysics

Specific arrestin conformations are coupled to distinct downstream effectors, which underlie the functions of many G-protein-coupled receptors (GPCRs). Here, using unnatural amino acid incorporation and fluorine-19 nuclear magnetic resonance (F-19-NMR) spectroscopy, we demonstrate that distinct receptor phospho-barcodes are translated to specific beta-arrestin-1 conformations and direct selective signalling. With its phosphate-binding concave surface, b-arrestin-1 'reads' the message in the receptor phospho-C-tails and distinct phospho-interaction patterns are revealed by F-19-NMR. Whereas all functional phosphopeptides interact with a common phosphate binding site and induce the movements of finger and middle loops, different phospho-interaction patterns induce distinct structural states of b-arrestin-1 that are coupled to distinct arrestin functions. Only clathrin recognizes and stabilizes GRK2-specific b-arrestin-1 conformations. The identified receptor-phosphoselective mechanism for arrestin conformation and the spacing of the multiple phosphatebinding sites in the arrestin enable arrestin to recognize plethora phosphorylation states of numerous GPCRs, contributing to the functional diversity of receptors.

submitted time 2016-05-12 Hits1025Downloads446 Comment 0

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