重组人血清白蛋白-干扰素α2b融合蛋白在PichiaPink系统中的表达

目的:比较PichiaPink表达系统和巴斯德毕赤酵母GS115在表达外源蛋白方面的差异,对PichiaPink表达系统的潜在优点进行评价。方法:以重组人血清白蛋白-干扰素α2b融合蛋白(HSA-IFN-α2b)为报告蛋白,构建相关载体,分别转化PichiaPink系统菌株和巴斯德毕赤酵母GS115菌株,诱导HSA-IFN-α2b表达并测定表达水平;通过SDS-PAGE检测HSA-IFN-α2b在PichiaPink系统中的降解程度。结果:PichiaPink系统几乎所有的转化子都可以表达HSA-IFN-α2b,而GS115菌株只有60%的转化子能表达HSA-IFN-α2b;同一种Pink菌株中,整合有高拷贝数表达载体pPink-HC的菌株表达量高于整合有低拷贝数表达载体pPink-LC的菌株;Pink蛋白酶缺陷菌株在复杂培养基(YPD,BMMY)中HSA-IFN-α2b基本没有降解,而在合成培养基(BSM)中降解现象明显。结论:PichiaPink表达系统产生的转化子较GS115菌株产生的转化子易于筛选;PichiaPink系统蛋白酶缺陷菌株可明显减少外源蛋白降解。这些结果为利用PichiaPink表达系统高水平和大规模制备外源蛋白提供了实验依据。     

海南自然保护区尺蛾科昆虫β多样性的研究

β多样性研究主要集中在植物群落上,对动物群落并联系系统发育β多样性的研究却较少。鉴于此,本研究以海南省5个自然保护区的尺蛾科昆虫为例,探究这些保护区的昆虫群落之间的β多样性及其形成机制。通过分子和形态学方法,将采集的尺蛾科昆虫成虫样本鉴定到种,并建立它们的系统发育树。分别选取了两个类型的β多样性指数：传统的Jaccard指数、Bray-Curtis指数和系统发育β多样性指数Dpw,用于比较不同样点间β多样性的变化。结合地理距离、飞行能力以及环境因子,运用mantel检验、RDA及偏RDA分析等方法探究海南尺蛾科昆虫β多样性的形成机制。结果表明,Jaccard指数和Dpw指数与19个环境因子中的等温性（bio_6）、最冷月最低温度（bio_9）和最湿季度平均温度（bio_11）这3个环境因子存在显著相关,与地理距离和飞行能力无显著相关,而Bray-Curtis指数与上述因子均无显著相关关系。3个环境因子对各β多样性指数的综合解释力都达到了79%以上,各自的解释力均在19%以上。分析表明,在海南5个自然保护区中,尺蛾科昆虫β多样性的形成主要受环境因子尤其是温度的影响。     

2010-2019年不同海湾迁徙水鸟栖息地适宜性变化对比研究

滨海湿地是迁徙水鸟的重要迁飞通道和主要栖息地,评估沿海迁徙水鸟栖息地适宜性及变化态势能为栖息地的合理规划与管理提供科学参考,对迁徙水鸟的保护有重要意义。选择紧邻城市和乡村的深圳湾和雷州湾为研究区,在水鸟栖息地生态系统类型分类的基础上,通过层次分析法确定水鸟栖息地适宜性评价因子,设计栖息地、食物、水分、人类干扰条件及其子类的权重,对栖息地适宜性进行等级划分,分析比较2010-2019年迁徙水鸟栖息地适宜性的时空分布差异,探索适宜性变化差异的原因并给出合理化建议。结果表明：（1）2010-2019年深圳湾有193.4 hm²强干扰区域转变化为中等及弱干扰;雷州湾有16.36 hm²的中等干扰转化为弱、无干扰;（2）深圳湾栖息地适宜性以中等适宜类型为主,2010年和2019年面积占比分别为83.74%和88.71%;雷州湾栖息地适宜性主要以较适宜和中等适宜类型为主,2010年面积占比为86.72%,2010-2019年面积占比基本不变,总体适宜性高于深圳湾。（3）2010-2019年,深圳湾不适宜和较适宜面积分别减少245.54 hm²和26.37 hm²,均转化为中等适宜类型;雷州湾有24.31 hm²的中等和较适宜栖息地转化为适宜类型。     

近10年来蒙古高原植被覆盖变化对气候的响应

基于东亚干旱半干旱地区内蒙古和蒙古国67个气象站的观测资料和SPOTVEGETATION归一化植被指数(NDVI)数据,借助线性趋势、MK趋势性检验、最大化合成法和相关分析等常用数理统计方法,研究了内蒙古和蒙古国地区的植被覆盖变化和气候变化及其响应关系。结果表明:①近49年内蒙古和蒙古国地区年均气温显著上升,降水变化不明显。年均气温在空间上呈现出南高北低的空间分布格局,降水量表现出由西向东递增趋势。②空间分布上,内蒙的植被覆盖状况好于蒙古国。时间变化上,该地区植被覆盖变化分为2个阶段,1998—2001年NDVI呈整体退化趋势,2002—2012年波动上升,其中2009—2012年连续3a上升。空间变化上,内蒙古境内植被退化的区域主要集中在锡林郭勒盟周边地区,蒙古国境内退化的区域分布在中西部地区。③蒙古国境内荒漠和草原植被NDVI与降水呈正相关关系,与气温呈负相关。而对于内蒙古而言荒漠和草原植被的NDVI也与降水呈正相关关系,森林植被与气温呈正相关。就政策层面:内蒙古区域近年来受国家重大生态政策退耕还林、退牧还草的影响,大部分东部和西部植被恢复较快。在今后如果增强两国的文化和政策交流学习,将会对未来的游牧民族文化的保留和发展提供契机。     

SWAT模型对景观格局变化的敏感性分析——以丹江口库区老灌河流域为例

景观的空间配置与类型组成能够对流域的产流、产沙及非点源污染产生影响。在以往SWAT模型研究中,往往默认水文模型考虑了该影响。为分析SWAT模型对不同景观格局变化的敏感性,根据老灌河流域2000年土地利用在各子流域的组成,模拟研究区更为破碎、复杂的景观空间配置,通过设置多套试验参数,利用SWAT模型生成基于不同景观格局的模拟结果。结果表明,SWAT模型不能反映除坡度和面积变化之外的景观水平下各斑块之间因景观空间格局改变对流域产流、产沙以及非点源污染的影响;模型通过其他参数的调整,弥补了模型分析数据的不足,使实测数据与模型部分结果高度吻合。这表明,一个能够反映流域部分水文特征的SWAT模型,未必是对研究区真实情形的模拟,而是各个参数间平衡的结果。因此,在利用SWAT模型分析模拟景观变化时,不应默认模型能够模拟景观空间格局改变对流域水文过程的影响,同时研究者可以通过划分坡度带,提高模型对不同坡度土地利用的敏感性。     

Exercise increases the release of NAMPT in extracellular vesicles and alters NAD + activity in recipient cells

Aging is associated with a loss of metabolic homeostasis, with cofactors such as nicotinamide adenine dinucleotide (NAD⁺) declining over time. The decrease in NAD⁺ production has been linked to the age‐related loss of circulating extracellular nicotinamide phosphoribosyltransferase (eNAMPT), the rate‐limiting enzyme in the NAD⁺ biosynthetic pathway. eNAMPT is found almost exclusively in extracellular vesicles (EVs), providing a mechanism for the distribution of the enzyme in different tissues. Currently, the physiological cause for the release of eNAMPT is unknown, and how it may be affected by age and physical exercise. Here, we show that release of small EVs into the bloodstream is stimulated following moderate intensity exercise in humans. Exercise also increased the eNAMPT content in EVs, most prominently in young individuals with higher aerobic fitness. Both mature fit and young unfit individuals exhibited a limited increase in EV‐eNAMPT release following exercise, indicating that this mechanism is related to both the age and physical fitness of a person. Notably, unfit mature individuals were unable to increase the release of eNAMPT in EVs after exercise, suggesting that lower fitness levels and aging attenuate this important signalling mechanism in the body. EVs isolated from exercising humans containing eNAMPT were able to alter the abundance of NAD⁺ and SIRT1 activity in recipient cells compared to pre‐exercise EVs, indicating a pathway for inter‐tissue signalling promoted through exercise. Our results suggest a mechanism to limit age‐related NAD⁺ decline, through the systemic delivery of eNAMPT via EVs released during exercise.     

Systematic analysis of multigene predictors in gastric cancer exploiting gene expression signature

Gastric cancer (GC) is the second most common cause of cancer death worldwide but could be more curable if diagnosed at an earlier stage. At present, the capability to predict the efficaciousness of molecular diagnosis for GC for each patient remains elusive. The purpose of this study was to identify tumor biomarkers through systems analysis of multigene predictors exploiting the available data resource. In this study, we investigated the top 10% overexpressed genes in GC from five data sets of the Oncomine platform, with 265 GC samples versus 174 normal gastric mucosa samples. Sixteen candidate genes were identified as predictors of GC, of which 14 genes were verified through the comparison of expression levels in specimens from normal (chronic gastritis, 21 samples) and GC groups (38 samples). In addition, unique molecular portraits of diffuse adenocarcinoma (DA), intestinal adenocarcinoma (IA), and mixed adenocarcinoma (MA) were studied through Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analysis, where DA showed higher extracellular matrix alteration while IA and MA showed higher cell-cycle alteration than other types. We also found that the elevated expressions of genes during GC progression were independent of gene mutations, and high core-binding factor subunit β expression is correlated with a high overall survival rate in GC patients. Our research may provide an efficient clinical diagnosis of GC at an early stage with high accuracy and thus help improve the overall survival rate through early therapeutic interventions.     

Population Differences in Brain Morphology and Microstructure among Chinese,Malay, and Indian Neonates

We studied a sample of 75 Chinese, 73 Malay, and 29 Indian healthy neonates taking part in a cohort study to examine potential differences in neonatal brain morphology and white matter microstructure as a function of ethnicity using both structural T2-weighted magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI). We first examined the differences in global size and morphology of the brain among the three groups. We then constructed the T2-weighted MRI and DTI atlases and employed voxel-based analysis to investigate ethnic differences in morphological shape of the brain from the T2-weighted MRI, and white matter microstructure measured by fractional anisotropy derived from DTI. Compared with Malay neonates, the brains of Indian neonates’ tended to be more elongated in anterior and posterior axis relative to the superior-inferior axis of the brain even though the total brain volume was similar among the three groups. Although most anatomical regions of the brain were similar among Chinese, Malay, and Indian neonates, there were anatomical variations in the spinal-cerebellar and cortical-striatal-thalamic neural circuits among the three populations. The population-related brain regions highlighted in our study are key anatomical substrates associated with sensorimotor functions.