基线血清外泌体miR-155-5p联合乙型肝炎病毒DNA定量实验预测聚乙二醇干扰素治疗乙型肝炎e抗原阳性慢性乙型肝炎的疗效

探讨聚乙二醇干扰素(peginterferon, Peg-IFN)治疗乙型肝炎e抗原(hepatitis B e antigen, HBeAg)阳性慢性乙型肝炎(chronic hepatitis B, CHB)患者48周后,基线血清外泌体miR-155-5p表达水平联合乙型肝炎病毒DNA定量实验在预测HBeAg血清学转换中的价值。回顾性分析2016年6月至2019年6月在本中心初次接受抗病毒治疗的HBeAg阳性CHB患者88例。根据Peg-IFN治疗48周后是否发生HBeAg血清学转换,将患者分为治疗应答组和无应答组。采用多因素logistic回归探讨预测Peg-IFN治疗应答的因子,并应用受试者工作特征(receiver operating characteristic, ROC)曲线下面积评估预测效能。结果发现基线血清外泌体miR-155-5p(OR＝2.193,95% CI 1.315～3.655,P＝0.003)和HBV DNA(OR＝0.398,95% CI 0.163～0.976,P＝0.036)是Peg-IFN治疗效果的独立预测因子。基线血清外泌体miR-155-5p和HBV DNA的截断值分别取2.3和7.2 log₁₀IU/mL时,相应的ROC曲线下面积分别为0.788(95% CI 0.682～0.893)和0.704(95% CI 0.577～0.824)。基线血清外泌体miR-155-5p表达水平≥2.3且HBV DNA定量≤7.2 log₁₀IU/mL的患者,Peg-IFN治疗48周后其HBeAg血清学转换率最高,为66.67% (10/15);而基线血清外泌体miR-155-5p表达水平<2.3且HBV DNA定量>7.2 log₁₀IU/mL的患者,Peg-IFN 治疗48周后其HBeAg血清学转换率最低,仅为3.03%(1/33)。这些结果表明,基线血清外泌体miR-155-5p表达水平联合HBV DNA定量实验可以作为Peg-IFN 治疗HBeAg阳性CHB疗效的预测因子,对于优化CHB的抗病毒治疗有积极作用。     

Maternal control of embryogenesis by MPK6 and its upstream MKK4/MKK5 in Arabidopsis

In flowering plants, developing embryos reside in maternal sporophytes. It is known that maternal generation influences the development of next‐generation embryos; however, little is known about the signaling components in the process. Previously, we demonstrated that Arabidopsis mitogen‐activated protein kinase 6 (MPK6) and MPK3 play critical roles in plant reproduction. In addition, we noticed that a large fraction of seeds from mpk6 single‐mutant plants showed a wrinkled seed coat or a burst‐out embryo phenotype. Here, we report that these seed phenotypes can be traced back to defective embryogenesis. The defective embryos have shorter suspensors and reduced growth along the longitudinal axis. Furthermore, the cotyledons fail to bend over to progress to the bent‐cotyledon stage. As a result of the uneven circumference along the axis, the seed coat wrinkles to develop raisin‐like morphology after dehydration. In more severe cases, the embryo can be pushed out from the micropylar end, resulting in the burst‐out embryo seed phenotype. Genetic analyses demonstrated that the defective embryogenesis of the mpk6 mutant is a maternal effect. Heterozygous or homozygous mpk6 embryos have defects only in mpk6 homozygous maternal plants, but not in wild‐type or heterozygous maternal plants. The loss of function of MKK4/MKK5 also results in the same phenotypes, suggesting that MKK4/MKK5 might act upstream of MPK6 in this pathway. The maternal‐mediated embryo defects are associated with changes in auxin activity maxima and PIN localization. In summary, this research demonstrates that the Arabidopsis MKK4/MKK5–MPK6 cascade is an important player in the maternal control of embryogenesis.     

植被格局对侵蚀产沙影响的研究评述

土壤侵蚀是人类可持续发展的重要挑战,植被重建则是防控侵蚀产沙的有效手段。在当前水土资源日益稀缺的新形势下,优化植被布局将成为黄土高原等生态脆弱地区未来阻蚀减沙、改善环境的重要途径,有关植被格局对侵蚀产沙影响的科技需求更加急迫、意义更加重要。为此,从坡面与流域两个尺度,总结评述了侵蚀产沙研究中的植被格局表征、侵蚀产沙对植被格局的变化响应两个议题的研究进展。分析认为,目前主要存在缺乏反映侵蚀产沙过程的植被格局表征指数、较少考虑植被与地形叠置格局对侵蚀产沙的耦合影响、尚未建立侵蚀产沙对植被格局的直观响应关系等问题。为促进有关研究,今后在格局指数和耦合关系的构建中应重视植被和地形对侵蚀产沙过程的耦合影响,并选用具有良好应用精度的分布式物理成因模型,以获得反映植被格局影响的流域侵蚀产沙结果。同时,可通过采用GIS空间分析技术,设计获得更多的典型植被格局及对应情景的侵蚀产沙,以丰富基础资料,减少信息干扰。     

基于三维生态足迹模型扩展的土地承载力指数研究——以温州市为例

生态足迹模型是土地承载力评价的重要方法。通过将Niccolucci三维生态足迹模型中足迹深度的取值范围从大于等于1扩展到大于等于0,将生态盈余状态的分析纳入一个统一的三维模型框架,实现了自然资源消费对资源流量和资源存量占用程度在核算上的统一。以温州市为例,运用扩展后的三维模型计算了2000—2012年间温州市的生态足迹、足迹深度、生态赤字(盈余)。在此基础上,引入粮食压力指数、水资源压力指数、碳汇压力指数、建设压力指数和土地综合负担指数等土地承载力评价指数,判断当前市域土地是否处于超载状态,以及超载程度。研究结果表明:2000—2012年间,温州市人均生态足迹从整体生呈逐年上升的趋势,人均生态生产性土地面积基本保持不变,生态赤字严重且逐年上升,温州市土地承担着巨大压力;2000—2012年间温州市足迹深度在4—6之间,自然资源流量远远不能满足自然资源需求,需要消耗大量的自然资源存量来支撑当前的发展和消费;温州市粮食压力指数、水资源压力指数、碳汇压力指数、土地综合压力指数均大于1,耕地、水域、林地均处于超载状态,且自2000年以来,温州市土地所承载的自然资源消费压力是其承载能力的4倍以上。     

Impacts of COX-1 gene polymorphisms on vascular outcomes in patients with ischemic stroke and treated with aspirin

As the key point of function for aspirin to educe anti-platelet effects, cyclooxygenase-1 (COX-1) gene polymorphisms have long been suspected as a potential cause for aspirin nonresponsiveness. But this hypothesis has not been confirmed by large longitudinal studies. This study prospectively evaluated the impacts of COX-1 gene polymorphisms on stroke recurrence and other vascular events in a large cohort of Chinese patients with ischemic stroke and treated with aspirin. Between December 2009 and October 2012, consecutive patients with ischemic stroke and treated with aspirin were enrolled. Polymorphisms of four alleles (rs1330344, rs10306114, rs3842788 and rs5788) in COX-1 gene were determined at baseline. The primary endpoint was a composite of nonfatal ischemic stroke, myocardial infarction, and death from cardiovascular causes. Impacts of COX-1 gene polymorphisms on vascular outcomes were evaluated with multivariate analysis. A total of 859 patients were included in data analysis. The minor allele frequencies of rs1330344, rs10306114, rs3842788 and rs5788 were 38.53%, 0.12%, 6.64% and 5.53%, respectively. During 14.64 ± 7.44 months of follow-up, primary endpoint was observed in 67 (7.80%) patients. Incidence of primary endpoint was higher in patients with CC genotype of rs1330344 than in patients with CT or TT genotype (HR = 1.916, 95% CI: 1.126–3.260, P = 0.016). After being adjusted for potential confounding factors, rs1330344 CC genotype was still independently associated with incidence of primary endpoint (HR = 1.958, 95% CI: 1.151–3.332, P = 0.013). The impacts of other three tested polymorphisms on primary endpoint were unremarkable. In conclusion, in Chinese patients with ischemic stroke and treated with aspirin, CC genotype of rs1330344 may increase the risk of subsequent vascular events.     

Using Heading date 1 preponderant alleles from indica cultivars to breed high‐yield,high‐quality japonica rice varieties for cultivation in south China

Heading date 1 (Hd1) is an important gene for the regulation of flowering in rice, but its variation in major cultivated rice varieties, and the effect of this variation on yield and quality, remains unknown. In this study, we selected 123 major rice varieties cultivated in China from 1936 to 2009 to analyse the relationship between the Hd1 alleles and yield‐related traits. Among these varieties, 19 haplotypes were detected in Hd1, including two major haplotypes (H8 and H13) in the japonica group and three major haplotypes (H14, H15 and H16) in the indica group. Analysis of allele frequencies showed that the secondary branch number was the major aimed for Chinese indica breeding. In the five major haplotypes, SNP₃₁₆(C‐T) was the only difference between the two major japonica haplotypes, and SNP₄₉₅(C‐G) and SNP₆₁₄(G‐A) are the major SNPs in the three indica haplotypes. Association analysis showed that H16 is the most preponderant allele in modern cultivated Chinese indica varieties. Backcrossing this allele into the japonica variety Chunjiang06 improved yield without decreasing grain quality. Therefore, our analysis offers a new strategy for utilizing these preponderant alleles to improve yield and quality of japonica varieties for cultivation in the southern areas of China.     

A Latent Model to Detect Multiple Clusters of Varying Sizes

Summary This article develops a latent model and likelihood‐based inference to detect temporal clustering of events. The model mimics typical processes generating the observed data. We apply model selection techniques to determine the number of clusters, and develop likelihood inference and a Monte Carlo expectation–maximization algorithm to estimate model parameters, detect clusters, and identify cluster locations. Our method differs from the classical scan statistic in that we can simultaneously detect multiple clusters of varying sizes. We illustrate the methodology with two real data applications and evaluate its efficiency through simulation studies. For the typical data‐generating process, our methodology is more efficient than a competing procedure that relies on least squares.     

Isolation,structure modeling and function characterization of a trypsin inhibitor from <Emphasis Type="Italic">Cassia obtusifolia</Emphasis>

A trypsin inhibitor gene (CoTI1) from Cassia obtusifolia was isolated and the deduced amino acid sequence was attributed to the Kunitz-type trypsin inhibitor. The recombined CoTI1, expressed in E. coli, exhibited strong inhibitory effect on bovine trypsin and trypsin-like proteases from Helicoverpa armigera, Spodoptera exigua, and Spodoptera litura. CoTI1 thus presents insecticidal properties that may be useful for the genetic engineering of plants. Leu84, Arg86 and Thr88 were predicted as three key residues by molecular modeling in which Arg86, inserted into the substrate pocket of trypsin, interacted directly with residue Asp189 of trypsin causing the specific inhibition against trypsin. The predicted results were confirmed by site-directed mutagenesis with L84A, R86A and T88A, respectively. The substantial changing expression level of CoTI1 under salt, drought and abscisic acid treatment suggested that CoTI1 might play important role in the resistance against abiotic stress.