Soil organic carbon stocks in China and changes from 1980s to 2000s

The estimation of the size and changes of soil organic carbon (SOC) stocks is of great importance for decision makers to adopt proper measures to protect soils and to develop strategies for mitigation of greenhouse gases. In this paper, soil data from the Second State Soil Survey of China (SSSSC) conducted in the early 1980s and data published in the last 5 years were used to estimate the size of SOC stocks over the whole profile and their changes in China in last 20 years. Soils were identified as paddy, upland, forest, grassland or waste‐land soils and an improved soil bulk density estimation method was used to estimate missing bulk density data. In the early 1980s, total SOC stocks were estimated at 89.61 Pg (1 Pg=10³ Tg=10¹⁵ g) in China's 870.94 Mha terrestrial areas covered by 2473 soil series. In the paddy, upland, forest and grassland soils the respective total SOC stocks were 2.91 Pg on 29.87 Mha, 10.07 Pg on 125.89 Mha, 34.23 Pg on 249.32 Mha and 37.71 Pg on 278.51 Mha, respectively. The SOC density of the surface layer ranged from 3.5 Mg ha⁻¹ in Gray Desery grassland soils to 252.6 Mg ha⁻¹ in Mountain Meadow forest soils. The average area‐weighted total SOC density in paddy soils (97.6 Mg ha⁻¹) was higher than that in upland soils (80 Mg ha⁻¹). Soils under forest (137.3 Mg ha⁻¹) had a similar average area‐weighted total SOC density as those under grassland (135.4 Mg ha⁻¹). The annual estimated SOC accumulation rates in farmland and forest soils in the last 20 years were 23.61 and 11.72 Tg, respectively, leading to increases of 0.472 and 0.234 Pg SOC in farmland and forest areas, respectively. In contrast, SOC under grassland declined by 3.56 Pg due to the grassland degradation over this period. The resulting estimated net SOC loss in China's soils over the last 20 years was 2.86 Pg. The documented SOC accumulation in farmland and forest soils could thus not compensate for the loss of SOC in grassland soils in the last 20 years. There were, however, large regional differences: Soils in China's South and Eastern parts acted mainly as C sinks, increasing their average topsoil SOC by 132 and 145 Tg, respectively. In contrast, in the Northwest, Northeast, Inner Mongolia and Tibet significant losses of 1.38, 0.21, 0.49 and 1.01 Pg of SOC, respectively, were estimated over the last 20 years. These results highlight the importance to take measures to protect grassland and to improve management practices to increase C sequestration in farmland and forest soils.     

骨组织中细胞的受力分析

基于骨陷窝中组织液和细胞具有的不可压缩性,以及组织液通过骨小管在骨陷窝裼 流动,得到了细胞所受压力的新的表达式。对该表达式的讨论结果表明它能够描述细胞的主要力学特性,例如：松弛和滞后效应。并根据眩表达式,求得细胞的松弛时间为２．４ｍｓ,与Ｃｏｗｉｎ等人估计值（４．９ｍｓ）接近。而在阶跃载荷下细胞所受最大压力为外力的一半,高于Ｃｏｗｉｎ等人的估计值（１２％）。     

Hydrophilic C terminus of Salicornia europaea vacuolar Na+/H+ antiporter is necessary for its function

Plant vacuolar Na⁺/H⁺ antiporters play important roles in cellular ion homeostasis, vacuolar pH regulation and sequestration of Na⁺ ions into the vacuole. Previous research showed that hydrophilic C-terminal region of Arabidopsis AtNHX1 negatively regulates the Na⁺/H⁺ transporting activity. In this study, we truncated the hydrophilic C terminus of a vacuolar Na⁺/H⁺ antiporter gene from Salicornia europaea (SeNHX1) to generate its derivative, SeNHX1- ΔC. Expression of SeNHX1 and SeNHX1- ΔC in yeast mutant showed that SeNHX1 significantly improved the tolerance to NaCl; however, the expression of SeNHX1- ΔC enormously decreased the tolerance to NaCl. Overall, these results suggest that the hydrophilic C-terminal region of SeNHX1 is required for Na⁺/H⁺ exchanging activity of SeNHX1.     

毛脉蓼系统分类位置的修订

在《中国植物志》以及各地方植物志中关于毛脉蓼Polygonum ciliinerve (Nakai) Ohwi的分类位置还存在争议, 鉴于此, 本研究应用扫描电子显微镜、常规石蜡切片以及表皮离析方法对毛脉蓼的营养和繁殖器官进行了观察, 并对毛脉蓼的系统分类位置进行了全面的分析和探讨。结果表明, 毛脉蓼的主要药用部位是块茎, 而不是块根, 且来源于匍匐茎节上的腋芽或者顶芽; 叶的上表皮细胞近长方形, 下表皮浅波状, 叶上、下面沿叶脉均具乳头状突起, 且其叶上、下表皮均具多数腺毛; 叶主脉中5个维管束呈一轮分布, 叶柄横切面具10个维管束, 其中7个小的排成一圈, 1个较大的维管束位于沟槽近中央的部位, 而另2个小的维管束位于沟槽两侧的突起中; 果皮的微形态为孔穴状纹饰, 种子横切面为三棱形。由于这些结构与何首乌P. multiflorum都有显著的差异, 尤其二者的药用部位在形态发生和结构特征上有着本质的区别, 故建议将毛脉蓼作为一个独立的种, 而非何首乌的变种。     

人血纤维蛋白溶酶原K5环的基因合成、表达、纯化与活性鉴定

 根据大肠杆菌遗传密码的偏爱性 ,人工合成人血纤维蛋白溶酶原 K5全基因 ,并在原核系统中以硫氧还蛋白融合蛋白的形式实现了高效表达 .重组蛋白通过 Ni2 +金属螯合层析得到初步纯化 ,通过肠激酶切割去除了融合标签 .应用鸡胚尿囊膜实验检测切割后的 rh K5的生物学活性 ,发现与对照组相比 ,rh K5能明显地降低血管管径、血管总面积以及血管总面积与视野面积的比值 ,表明切割后的产物具有显著抑制新生血管生成的生物学活性 .为进一步研究和开发抗血管生成药物奠定了基础 .     

延髓腹外侧B(x)tzinger复合体呼吸时相转换效应的研究

实验在40只氨基甲酸乙酯麻醉的成年家兔上进行,观察电刺激Btzinger复合体(Bt.C)对呼吸节律的影响.结果表明: (1)吸气相早期短串电刺激Bt.C导致膈神经放电被短暂抑制,被抑制的程度与刺激强度呈正相关.当刺激落位在吸气相中、晚期时,可导致吸气提前终止("吸气切断"),之后跟随一缩短的呼气相.导致"吸气切断"的阈强度与刺激落位呈负相关.(2)呼气相短串电刺激Bt.C,可诱导膈神经短暂放电,呼气相晚期诱导出现放电之后往往跟随一正常的吸气放电,结果导致该呼气相缩短.该效应亦具有刺激强度、刺激落位依赖性.结果提示: Bt.C参与吸气向呼气以及呼气向吸气的时相转换.     

Phylogenomics of Hemiptera (Insecta: Paraneoptera) based on mitochondrial genomes

Hemiptera is the largest order in Paraneoptera and the fifth largest in Insecta. Disputes about hemipteran phylogeny have concerned the monophyly of Auchenorrhyncha and relationships between the suborders Fulgoromorpha, Cicadomorpha, Coleorrhyncha and Heteroptera. In a phylogenomic study of Hemiptera, we add two new mitochondrial genomes of Peloridiidae (Coleorrhyncha) to those reported in GenBank, to complete the taxon sampling of all suborders. We used two types of data – amino acid sequences and nucleotides of various combinations between protein coding genes, tRNAs and rRNAs – to infer the phylogeny of Hemiptera. In total 27 taxa of Paraneoptera were sampled, 24 of them being hemipterans. Bayesian inference, maximum likelihood and maximum parsimony analyses were employed. The relationship of Cicadomorpha + Heteroptera is always stable in the results with different combinations between data types and phylogenetic methods, but our results challenge the monophyly of ‘Homoptera’ and Auchenorrhyncha. In evaluating the relative contribution of each gene, the phylograms generated by single genes CO1, ND1, ND2, ND4 and ND5, respectively, closely matched the tree yielded by the combined datasets. In light of the taxon‐sampling sensitivity of trees based on mitochondrial genomes, the results need to be tested with further data from nuclear genes.     

中国林蛙新亚种研究

本文根据采集于陕西户县、甘肃榆中,四川康定和吉林白河产中国林蛙Rana chensinensis 371号标本,对其形态、染色体组型、C带、银带及血清LDH同工酶电泳酶带进行了比较研究,发现榆中、康定和白河的标本与中国林蛙模式产地户县的标本两两之间均存在显著差异,因此确定榆中、康定和白河产中国林蛙为三个新亚种。     

Antisense oligonucleotide to insulin-like growth factorⅡ induces apoptosis in human ovarian cancer AO cellline

INTRODUCTIONOvariancancerisoneofthemostcommonfatalgynecologicmalignanciesin1.Towhomcorrespondenceshouldbeaddressed.theworld[1].Clinicaltreatmentofovariancancer,thoughwithgreatprogress,hasbeenimpededbyresistencetochemicaltherapy.Recently,inductionofapoptos…