雷帕霉素诱导β-珠蛋白家族基因座位重塑调控该基因的转换表达

β-珠蛋白基因编码异常导致的β-地中海贫血是许多亚洲国家最常见的血红蛋白病。深入研究珠蛋白基因表达的分子基础和表观遗传机制,是探索治疗地中海贫血新方案的关键。本研究利用FAIRE、3C及ChIP等主要技术方法,探讨雷帕霉素诱导CD4^(+)T细胞核内染色质重塑过程中,β-珠蛋白家族基因座位的三维相互作用网络及其重塑在功能上调控基因表达的分子机制。结果显示,雷帕霉素处理浓度从低到高的变化过程中,珠蛋白基因染色质的开放程度、基因启动子区与调控元件LCR之间的相互作用频率以及CTCF在基因启动子区的富集效率发生不同的改变,这种变化导致了基因表达模式也呈现相同的变化趋势。10 nmol/L浓度处理时,染色质可及性降低,基因表达下降(P<0.05);20 nmol/L和50 nmol/L浓度时,染色质可及性增加,基因表达上调(P<0.05)。本研究通过这种动态的变化过程阐述了β-珠蛋白家族基因表达转换调控的分子机制,为临床精准治疗提供了理论与临床实践基础。

FGOALS-g模式及其参与CMIP6的方案

为参加第六次国际耦合模式比较计划(CMIP6)和进一步提高模式的模拟能力,大气科学和地球流体力学数值模拟国家重点实验室(LASG)模式团队发展了新一代的格点大气版本的FGOALS-g耦合模式。新版本模式在大气分辨率、海洋网格,以及各分量模式的物理过程等方面都有一定的改进,并正在参与CMIP6最核心的试验以及多个CMIP6模式比较子计划试验。给定CMIP6外强迫,模式在工业革命前参照试验(piControl)和大气模式比较计划(AMIP)试验中模拟的初步结果都比较合理。

Coupled modeling of land hydrology-regional climate including human carbon emission and water exploitation

碳排出物和水使用是人的活动的二种主要类型。揭示这二项活动是否能在中国修改水文学周期和气候系统，我们用地区性的气候模型 RegCM4 进行了数字实验的二个集合。在过去常学习气候的回答到人的碳排出物的第一个实验，因为碳排出物的影响能越过整个国家被检测，模型在全部中国上被设置。从第一个实验的结果揭示了温度可以显著地以超过 0.1 的率从 2007 ～ 2059 增加的那近表面的表情 ? 漠 ? 偉 ??? 猠散慮楲獯※ ?? 潬杮眠瑩 ? 楲楳杮琠浥数慲畴敲 ? 景吗？

The Long-Term Field Experiment Observatory and Preliminary Analysis of Land-Atmosphere Interaction over Hilly Zone in the Subtropical Monsoon Region of Southern China

To improve current understanding of the water cycle,energy partitioning and CO2 exchange over hilly zone vegetative land surfaces in the subtropical monsoon environment of southern China,a long-term field experiment observatory was set up at Ningxiang,eastern Hunan Province.This paper presents a preliminary analysis of the field observations at the observatory collected from August to November 2012.Results show that significant diurnal variations in soil temperature occur only in shallow soil layers(0.05,0.10,and 0.20 m),and that heavy rainfall affects soil moisture in the deep layers(≥ 0.40 m).During the experimental period,significant diurnal variations in albedo,radiation components,energy components,and CO2 flux were observed,but little seasonal variation.Strong photosynthesis in the vegetation canopy enhanced the CO2 absorption and the latent heat released in daylight hours;Latent heat of evaporation was the main consumer of available energy in late summer.Because the field experiment data are demonstrably reliable,the observatory will provide reliable long-term measurements for future investigations of the land-atmosphere interaction over hilly land surfaces in the subtropical monsoon region of southern China.

KLF7通过抑制缺氧诱导因子1α转录影响肉鸡脂肪组织发育

Krüppel样转录因子7(Krüppel-like factor 7,KLF7)是脂肪形成的负调控因子,而缺氧诱导因子1(hypoxia-inducible factor 1,HIF1)促进缺氧诱导的哺乳动物脂肪组织发育。本实验室前期利用ChIP-seq技术,发现在鸡的缺氧诱导因子1α(hypoxia-inducible factor 1 alpha,HIF1α)基因上游存在1个KLF7的结合峰,提示KLF7可能调控HIF1α基因转录。为此,本研究首先利用ChIP-PCR技术验证ChIP-seq结果,发现KLF7能够与HIF1α基因5′侧翼区结合。双荧光素酶报告基因与qRT-PCR结果显示,过表达KLF7能够显著下调HIF1α(-4432/-4182)的荧光素酶报告基因活性(P<0.01),抑制HIF1α基因表达。与野生型质粒相比,将生物信息学预测的KLF7结合基序"TGCGCAGCAA"(-4300/-4290)缺失突变后,HIF1α(-4432/-4182)报告基因活性显著增强(P<0.01)。此外,选取第19代1~7周龄东北农业大学高、低脂双向选择品系肉鸡(Northeast Agricultural University broiler lines divergently selected for abdominal fat content,NEAUHLF)作为实验材料,利用qRT-PCR检测HIF1α基因在肉鸡腹部脂肪组织中的表达规律。结果显示,HIF1α在1~7周龄高脂系肉鸡中的相对表达量均高于低脂系,提示HIF1α对鸡脂肪组织发育具有促进作用。在永生化鸡前体脂肪细胞系(immortalized chicken preadipocyte cell line,ICP1)诱导分化过程中,HIF1α相对表达量逐渐升高。综上所述,HIF1α是转录因子KLF7的一个靶基因,KLF7可能通过抑制HIF1α基因转录参与鸡脂肪组织发育过程。

Improving Simulation of the Terrestrial Carbon Cycle of China in Version 4.5 of the Community Land Model Using a Revised V_(cmax) Scheme

The maximum rate of carboxylation(Vcmax) is a key photosynthetic parameter for gross primary production(GPP) estimation in terrestrial biosphere models. A set of observation-based Vcmax values, which take the nitrogen limitation on photosynthetic rates into consideration, are used in version 4.5 of the Community Land Model(CLM4.5). However, CLM4.5 with carbon-nitrogen(CN) biogeochemistry(CLM4.5-CN) still uses an independent decay coefficient for nitrogen after the photosynthesis calculation. This means that the nitrogen limitation on the carbon cycle is accounted for twice when CN biogeochemistry is active. Therefore, to avoid this double nitrogen down-regulation in CLM4.5-CN, the original Vcmax scheme is revised with a new one that only accounts for the transition between Vcmax and its potential value(without nitrogen limitation). Compared to flux towerbased observations, the new Vcmax scheme reduces the root-mean-square error(RMSE) in GPP for China's Mainland by 13.7 g C m-2 yr-1, with a larger decrease over humid areas(39.2 g C m-2 yr-1). Moreover, net primary production and leaf area index are also improved, with reductions in RMSE by 0.8% and 11.5%, respectively.

Evaluation of the Community Microwave Emission Model Coupled with the Community Land Model over East Asia

The Community Microwave Emission Model (CMEM) developed by the European Centre for Me-dium-Range Weather Forecasts (ECMWF) can provide a link between surface states and satellite observations and simulate the passive microwave brightness temperature of the surface at low frequencies (from 1 GHz to 20 GHz).This study evaluated the performance of the CMEM cou-pled with the Community Land Model (CLM) (CMEM-CLM) using C-band (6.9 GHz) microwave brightness temperatures from the Advanced Microwave Scanning Radiometer on Earth Observing System (AMSR-E) over East Asia.Preliminary results support the argument that the simulated brightness temperatures of CMEM-CLM from July 2005 to June 2010 are comparable to AMSR-E observational data.CMEM-CLM performed better for vertical polarization,for which the root mean square error was approximately 15 K,compared to over 30 K for horizontal polarization.An evaluation performed over seven sub-regions in China indicated that CMEM-CLM was able to capture the temporal evolution of C-band brightness temperatures well,and the best correlation with AMSR-E appeared over western Northwest China (over 0.9 for vertical polarization).However,larger biases were found over southern North China and the middle and lower reaches of the Yangtze River.

Improving the simulation of terrestrial water storage anomalies over China using a Bayesian model averaging ensemble approach

作为全球能量和水分循环的关键参量,陆地水储量包括土壤水、地表水、地下水、积雪和生物体水等,在水文、气候、农业、生态等众多领域起重要影响。与地面观测和遥感反演相比,陆面模式在刻画陆地水储量的时空变率等方面具有明显优势。然而不同模式参数化方案以及大气强迫驱动导致陆地水储量模拟存在不确定。为了减少陆地水储量模拟不确定性,本研究建立了基于贝叶斯模型平均(BMA)和多强迫多模式集合的陆地水储量模拟系统,获得了中国区域1979–2008年陆地水储量数据集。选取2004–08年的数据与GRACE重力卫星数据比较分析,结果显示BMA集合模拟的陆地水储量异常(Terrestrial water storage anomalies,TWSA)优于所有单个模拟结果,与GRACE观测的TWSA有更高的相关系数和更小的误差。

Assimilating the LAI Data to the VEGAS Model Using the Local Ensemble Transform Kalman Filter: An Observing System Simulation Experiment

Information on the spatial and temporal patterns of surface carbon flux is crucial to understanding of source/sink mechanisms and projection of future atmospheric CO2 concentrations and climate. This study presents the construction and implementation of a terrestrial carbon cycle data assimilation system based on a dynamic vegetation and terrestrial carbon model Vegetation-Global-Atmosphere-Soil(VEGAS) with an advanced assimilation algorithm, the local ensemble transform Kalman filter(LETKF, hereafter LETKF-VEGAS). An observing system simulation experiment(OSSE) framework was designed to evaluate the reliability of this system, and numerical experiments conducted by the OSSE using leaf area index(LAI) observations suggest that the LETKF-VEGAS can improve the estimations of leaf carbon pool and LAI significantly, with reduced root mean square errors and increased correlation coefficients with true values, as compared to a control run without assimilation. Furthermore, the LETKF-VEGAS has the potential to provide more accurate estimations of the net primary productivity(NPP) and carbon flux to atmosphere(CFta).