转基因大豆MON89788芯片式数字PCR定量方法的建立

针对抗虫耐除草剂大豆转基因品系MON89788,从转基因植物基因组DNA的提取、核酸模板的质量和浓度控制、引物探针的筛选、PCR反应过程的建立等方面建立了一套完整的转基因大豆芯片式dPCR定量检测方法。本实验也对该方法的重复性和定量检测限进行考察。10组5%转基因品系大豆MON89788样品定量重复性RSD在1.17%-9.97%之间,均满足国际上转基因定量结果RSD小于25%的要求。用该方法对转基因含量为5%、1%、0.1%的大豆MON89788进行定量检测,其定量结果为5.20%、0.94%和0.11%,RSD分别为6.2%、3.6%和15.2%。该检测方法的定量限达到0.1%,能满足欧盟对转基因定量标识0.9%的要求。将本实验建立的方法用于转基因大豆的定量检测,能为规范我国转基因监管工作的实施提供强有力的技术支撑。     

ULK2 Ser 1027 Phosphorylation by PKA Regulates Its Nuclear Localization Occurring through Karyopherin Beta 2 Recognition of a PY-NLS Motif

Uncoordinated 51-like kinase 2 (ULK2), a member of the serine/threonine kinase family, plays an essential role in the regulation of autophagy in mammalian cells. Given the role of autophagy in normal cellular homeostasis and in multiple diseases, improved mechanistic insight into this process may result in the development of novel therapeutic approaches. Here, we present evidence that ULK2 associates with karyopherin beta 2 (Kapβ2) for its transportation into the nucleus. We identify a potential PY-NLS motif (⁷⁷⁴gpgfgssppGaeaapslRyvPY⁷⁹⁵) in the S/P space domain of ULK2, which is similar to the consensus PY-NLS motif (R/K/H)X _2–5PY. Using a pull-down approach, we observe that ULK2 interacts physically with Kapβ2 both in vitro and in vivo. Confocal microscopy confirmed the co-localization of ULK2 and Kapβ2. Localization of ULK2 to the nuclear region was disrupted by mutations in the putative Kapβ2-binding motif (P794A). Furthermore, in transient transfection assays, the presence of the Kapβ2 binding site mutant (the cytoplasmic localization form) was associated with a substantial increase in autophagy activity (but a decrease in the in vitro serine-phosphorylation) compared with the wild type ULK2. Mutational analysis showed that the phosphorylation on the Ser1027 residue of ULK2 by Protein Kinase A (PKA) is the regulatory point for its functional dissociation from Atg13 and FIP 200, nuclear localization, and autophagy. Taken together, our observations indicate that Kapβ2 interacts with ULK2 through ULK2’s putative PY-NLS motif, and facilitates transport from the cytoplasm to the nucleus, depending on its Ser1027 residue phosphorylation by PKA, thereby reducing autophagic activity.     

Cyclins,cyclin-dependent kinases and differentiation

Cyclin-dependent kinases and their regulatory subunits, the cyclins, are known to regulate progression through the cell cycle. Yet these same proteins are often expressed in non-cycling, differentiated cells. This review surveys the available information about cyclins and cyclin-dependent kinases in differentiated cells and explores the possibility that these proteins may have important functions that are independent of cell cycle regulation.     

Variations in Temperature Sensitivity (Q10) of CH4 Emission from a Subtropical Estuarine Marsh in Southeast China

Understanding the functional relationship between greenhouse gas fluxes and environmental variables is crucial for predicting the impacts of wetlands on future climate change in response to various perturbations. We examined the relationships between methane (CH₄) emission and temperature in two marsh stands dominated by the Phragmites australis and Cyperus malaccensis, respectively, in a subtropical estuarine wetland in southeast China based on three years of measurement data (2007–2009). We found that the Q₁₀ coefficient of CH₄ emission to soil temperature (Q_s10) from the two marsh stands varied slightly over the three years (P > 0.05), with a mean value of 3.38 ± 0.46 and 3.89 ± 0.41 for the P. australis and C. malaccensis stands, respectively. On the other hand, the three-year mean Q_a10 values (Q₁₀ coefficients of CH₄ emission to air temperature) were 3.39 ± 0.59 and 4.68 ± 1.10 for the P. australis and C. malaccensis stands, respectively, with a significantly higher Q_a10 value for the C. malaccensis stand in 2008 (P < 0.05). The seasonal variations of Q₁₀ (Q_s10 and Q_a10) differed among years, with generally higher values in the cold months than those in the warm months in 2007 and 2009. We found that the Q_s10 values of both stands were negatively correlated with soil conductivity, but did not obtain any conclusive results about the difference in Q₁₀ of CH₄ emission between the two tidal stages (before flooding and after ebbing). There were no significant differences in both Q_s10 and Q_a10 values of CH₄ emission between the P. australis stand and the C. malaccensis stands (P > 0.05). Our results show that the Q₁₀ values of CH₄ emission in this estuarine marsh are highly variable across space and time. Given that the overall CH₄ flux is governed by a suite of environmental factors, the Q₁₀ values derived from field measurements should only be considered as a semi-empirical parameter for simulating CH₄ emissions.     

具有阶段结构和免疫反应的病毒动力学模型的全局稳定性

研究了一类被感染细胞具有潜伏和活性两阶段以及免疫反应的病毒动力学模型.通过建立适当的Lyapunov泛函和使用LaSalle不变集原理,获得当σ≤1,ω≤1σ和σω1时,对应的未感染平衡点P,体液免疫未激活的无免疫感染平衡点M,体液免疫已激活的感染平衡点N是全局渐近稳定的充分条件.所获得结果推广了Nowak(1996)和Bangham(1997)的工作,得到了一些新结果.     

模拟穿透雨减少对锐齿栎(Quercus aliena var. acuteserrata)树干液流密度的影响

降水格局变化是全球气候变化的重要特征之一,未来气候变化下,较为频繁和严峻的干旱将威胁地球中纬度部分地区的森林,但森林植被如何响应季节性干旱胁迫及其机制尚不清楚。北亚热带-暖温带过渡区分布着以锐齿栎(Quercus aliena var.acuteserrata)为优势树种的落叶阔叶林,研究其水分蒸腾代谢过程对干旱的响应是评估气候变化对过渡区天然落叶阔叶林生态系统水碳影响的关键科学问题。在典型的锐齿栎天然林中通过开展模拟穿透雨减少大型野外实验,采用Granier热扩散式探针技术监测锐齿栎树干液流密度的动态变化,研究了不同径级锐齿栎树干液流密度对模拟干旱的响应规律。结果表明:(1)穿透雨减少对树干液流密度的影响呈现季节变异。在7月份,林内穿透雨减少显著降低了锐齿栎的树干液流密度,但生长季后期的10月份林内穿透雨减少反而使锐齿栎树干液流密度显著升高。(2)不同径级的锐齿栎树干液流密度在生长季内对干旱有不同的响应,特别是小径级的树干液流密度与其他径级有较多的不同。小径级的锐齿栎树干液流密度在5、7月份表现为减雨样地显著小于对照样地,在9、10月份则表现为减雨样地显著大于对照样地。中径级的锐齿栎树干液流密度在5、10月份表现为减雨样地显著大于对照样地,在7月份则表现为减雨样地极显著小于对照样地。大径级的锐齿栎树干液流密度在6、7月份表现为减雨样地显著小于对照样地,在10月份则表现为减雨样地显著大于对照样地。     

中国脉线蛉属二新种(脉翅目,褐蛉科)

记述中国脉线蛉属Neuronema 2新种,即条纹脉线蛉Neuronema striatum sp.nov.和梵净脉线蛉Neuronema fanjingshanum sp.nov..模式标本均保存在中国农业大学昆虫博物馆.