Molecular characterization and expression of metallothionein from freshwater pearl mussel,Hyriopsis schlegelii

Two metallothionein genes (HsMT1 and HsMT2) were first identified and described from Hyriopsis schlegelii. The open reading frame of HsMT1 and HsMT2 were 216 and 222 bp, encoding a protein of 71 and 73 amino acid residues. The deduced amino acid sequences showed they contained parts of typical MT characteristics, apart from HsMT2 lacked Cys–Cys motifs. The phylogenetic tree showed HsMT1 shared a high similarity with that of other molluscs, but HsMT2 was split into a distinct group separated from known molluscan MTs. HsMT1 exhibited constitutive expression in all examined tissues and the highest expression occurred in hepatopancreas, however, nearly all HsMT2 was just detected in gonad. After Cd exposure, their mRNA levels presented similar expression patterns. The transgenic bacteria of HsMT1 showed higher tolerance than HsMT2 in Cd environment. It was implied that HsMT1 and HsMT2 were involved in metal response but HsMT2 might have other physiological functions.     

伏牛山南、北坡植物物种多样性及其与主要生态因子的相关性

采用实地调查法对伏牛山南坡23个样地和北坡15个样地内的乔木、灌木和草本种类数以及乔木的Margalef 指数和Shannon-Wiener指数进行了统计分析和计算;在此基础上,运用典范对应分析(CCA)法筛选出影响南、北坡植物物种多样性的主要生态因子并进行了相关性分析.结果表明:南坡每个样地乔木、灌木和草本种类数的平均值分别为8.3、8.6和9.5,北坡分别为5.4、7.5和11.1;在海拔1 645～1 870m范围内,南坡样地的乔木、灌木和草本种类数均多于北坡样地.影响伏牛山南、北坡植物物种多样性的主要生态因子均为9个,它们之间略有差异但均可分为地形、气象和土壤3大类因子.相关性分析结果显示:北坡乔木的种类数、Margalef指数和Shannon-Wiener指数与土壤厚度均呈极显著(P＜0.01)正相关,与海拔呈极显著负相关;而南坡乔木的Margalef指数和Shannon-Wiener指数与土壤有机质含量呈极显著正相关.北坡草本种类数与大气温度以及土壤有机质和碱解氮含量均呈极显著或显著(P＜0.05)正相关;而南坡草本种类数则与海拔、土壤厚度和土壤有机质含量呈极显著或显著正相关,与坡度、阴阳坡和大气湿度呈显著或极显著负相关.除北坡的灌木种类数与坡向呈显著正相关外,南、北坡灌木种类数与9个主要生态因子的相关性均不显著.说明伏牛山南、北坡的乔木多样性主要与土壤厚度和有机质含量等土壤性状因子有关,草本多样性则与局地小气候因子关系密切,而影响灌木多样性变化的主要生态因子并不明确.     

Tert-Butylhydroquinone Alleviates Early Brain Injury and Cognitive Dysfunction after Experimental Subarachnoid Hemorrhage: Role of Keap1/Nrf2/ARE Pathway

Tert-butylhydroquinone (tBHQ), an Nrf2 activator, has demonstrated neuroprotection against brain trauma and ischemic stroke in vivo. However, little work has been done with respect to its effect on early brain injury (EBI) after subarachnoid hemorrhage (SAH). At the same time, as an oral medication, it may have extensive clinical applications for the treatment of SAH-induced cognitive dysfunction. This study was undertaken to evaluate the influence of tBHQ on EBI, secondary deficits of learning and memory, and the Keap1/Nrf2/ARE pathway in a rat SAH model. SD rats were divided into four groups: (1) Control group (n = 40); (2) SAH group (n = 40); (3) SAH+vehicle group (n = 40); and (4) SAH+tBHQ group (n = 40). All SAH animals were subjected to injection of autologous blood into the prechiasmatic cistern once in 20 s. In SAH+tBHQ group, tBHQ was administered via oral gavage at a dose of 12.5 mg/kg at 2 h, 12 h, 24 h, and 36 h after SAH. In the first set of experiments, brain samples were extracted and evaluated 48 h after SAH. In the second set of experiments, changes in cognition and memory were investigated in a Morris water maze. Results shows that administration of tBHQ after SAH significantly ameliorated EBI-related problems, such as brain edema, blood-brain barrier (BBB) impairment, clinical behavior deficits, cortical apoptosis, and neurodegeneration. Learning deficits induced by SAH was markedly alleviated after tBHQ therapy. Treatment with tBHQ markedly up-regulated the expression of Keap1, Nrf2, HO-1, NQO1, and GSTα1 after SAH. In conclusion, the administration of tBHQ abated the development of EBI and cognitive dysfunction in this SAH model. Its action was probably mediated by activation of the Keap1/Nrf2/ARE pathway.     

Molecular structural mechanics model for the mechanical properties of microtubules

The aim of this paper was to develop a structural mechanics (SM) model for the microtubules (MTs) in cells. The technique enables one to study the configuration effect on the mechanical properties of MTs and enjoys greatly improved computational efficiency as compared with molecular dynamics simulations. The SM model shows that the Young’s modulus has nearly a constant value around 0.83 GPa, whereas the shear modulus, two orders of magnitude lower, varies considerably with the protofilament number \(N\) and helix-start number \(S\) . The dependence of the bending stiffness and persistence length on the MT length and protofilament number \(N\) is also examined and explained based on the continuum mechanics theories. Specifically, the SM model is found to be in good agreement with available simulation and experiment results, showing its robustness in studying the static deformation of MTs and the potential for characterizing the buckling and vibration of MTs as well as the mechanical behaviour of intermediate and actin filaments.     

吉林桦甸二叠系寿山沟组的牙形刺及其地质时代

本文作者在寿山沟组命名剖面系统地采集了 38 个样品,其中 28 个样品中发现了牙形刺,主要有 Mesogondolella idahoensis , M.lamberi , M.siciliensis , Sweetognathus expansus , Sweetognathus sp. ,这一动物群清楚地证明寿山沟组的时代为早二叠世空谷期( Kungurian )最晚期的,仍没进入中二叠世。属特提斯牙形刺省,但海水温度可能稍低些。 Monodiexodina 的时代始于 Kungurian 期的最晚期。     

生物柴油植物膏桐高油高产品种的培育(英文)

在2005-2009年期间,利用从中国南部和西南部收集的80个不同的膏桐地理种源,在西双版纳建立膏桐种质资源圃30亩;在圃内开展其生物学特性和农艺性状的同时,对其中表现良好的6个地理种源做了进一步选择和培育。结果表明:80个种源的2年生时平均直径、树高和树冠分别为7.6cm、167cm和114cm,种子千粒重为0.676(0.477～0.879)kg;在这些种源中,根据单株产量和种子含油率的情况,对6个表现较好的种源开展了小规模试验,2年生时平均单株产量0.34kg,3年生时达1.38kg;在试验中,有一个种源表现尤为突出,自挂果以来种子产量逐年增加,二、三、四年生林分每公顷干种子产量分别为964.3kg、2000.6kg、2858.7kg,种子含油率40%～42%。另外,还利用野外发现的膏桐突变体成功地育出了膏桐新品种。以此为父本与其他种源杂交产生的后代,种子含油率较对照提高6个百分点,杂种种子含油率达41.2%。     

Synonymy of soil-feeding termites Pseudocapritermes sowerbyi and Pseudocapritermes largus,with evidence from morphology and genetics

Pseudocapritermes Kemner is a termite group that constructs subterranean gallery systems in topsoil. This genus is distributed in the Oriental region and contains 18 species. Dependence on the morphological measurements of soldiers makes the taxonomy of Pseudocapritermes difficult. In this study, we compared morphological characters of soldiers and adults of P. largus and P. sowerbyi. In addition, three fulllength mitochondrial genes (COI, COII, and 16S rRNA) were sequenced from a total of eight P. largus and P. sowerbyi colonies. Morphological comparison of soldiers showed that P. largus is larger than P. sowerbyi, but there was overlap in some measurements. In adults, the morphological characters of P. largus were congruent with those of P. sowerbyi. Sequence alignments of COI, COII, and 16S rRNA revealed a high pairwise genetic identity (ranging from 99.64 to 100%) between the two species, which suggested that P. largus and P. sowerbyi are the same species. Molecular phylogenetic analysis based on COII revealed that Pseudocapritermes belongs to the Termes group having soldiers with asymmetrical snapping mandibles and is more closely related to Sinocapritermes than to other Termes group genera distributed in China. Morphological similarity and genetic identity indicate that P. largus is a junior synonym of P. sowerbyi.     

Environmental conditions and genetic differentiation: what drives the divergence of coexisting Leymus chinensis ecotypes in a large-scale longitudinal gradient?

Aims The two coexisting Leymus chinensis ecotypes exhibit remarkable divergences in adaptive strategies under drought and salinity in semi-humid meadows and semi-arid steppes. In order to detect the major genetic and environmental factors dominating the intraspecific phenotype variations and ecotype formation, the questions regarding the two distinct phenotypic forms (ecotypes) in L. chinensis were addressed: (i) did environments drive the L. chinensis ecotype formation? (ii) was there a molecular basis for the morphological divergence between the two ecotypes? (iii) which driving force dominated the intraspecies divergence, divergent natural selection, genetic drift or stabilizing selection?Methods We applied a series experiments on demographical, morphological and physiological traits of two Leymus chinensis ecotypes with gray green (GG) and yellow green (YG) leaf color in nine wild sites along a longitudinal gradient from 114° to 124°E in northeast China. The environmental data including mean annual precipitation, mean annual temperature, elevation and soil properties were collected. We compared the differences of morphological, physiological and genetic differentiations between the two ecotypes.Important findings The GG type exhibited stronger fitness than YG type from the population densities, morphological traits (e.g. shoot height, leaf area, leaf and seed weights et al.), leaf mass per area (LMA) and physiological traits [relative water content (RWC), proline, soluble sugar contents]. Most of above phenotypes (e.g. total shoot densities, spike length et al.) were significantly correlated with mean annual precipitation, mean annual temperature and soil water content (SWC), rarely a correlated with soil pH and soil nutrient. Transplanted populations showed convergence trend by their leaf chlorophyll contents and osmotic adjustments (proline and soluble sugar contents) in the greenhouse, but still exhibited their divergences between two ecotypes in the outdoor transplantation, suggesting that whether L. chinensis ecotype differentiated could be largely affected by the environmental conditions. Furthermore, by the comparison result of quantitative genetic variation (Q ST) values from phenotypes with theoretical neutral genetic differentiation (F ST), differentiation in phenotypic traits greatly surpassed neutral predictions, implying that directional natural selection played a crucial role in L. chinensis ecotype differentiation. In addition, microsatellite analysis from Neighbor-joining tree and Bayesian assignment generated into two groups according to ecotypes, indicating molecular genetic differentiation also propelled the two ecotypes divergence. We conclude that L. chinensis population variations were driven by combing divergent natural selection (precipitation, temperature and SWCs) along the large-scale gradient and significantly intrinsic genetic differentiation.