转双抗虫基因107杨节肢动物群落特征及相对稳定性

于2015年5—9月对唐山市滦南县苗圃场内的转双抗虫基因(Bt Cry1Ac和API基因)107杨(简称:转抗虫基因107杨)及未转基因107杨(简称:对照杨)进行了节肢动物群落调查,利用群落特征指数、群落相似性系数、群落相对稳定性和主成分分析法对转抗虫基因107杨节肢动物群落特征、相似性、相对稳定性及主成分进行对比分析。调查共获得节肢动物6818头,隶属于2纲,8目,43科,58种。研究结果表明:转抗虫基因107杨和对照杨节肢动物群落中以鳞翅目、鞘翅目、膜翅目、双翅目昆虫为主要类群,其中鳞翅目昆虫个体数量最多;鳞翅目和半翅目昆虫个体数量与对照杨差异显著;在功能类群上,转抗虫基因107杨食叶昆虫个体数量较对照杨显著减少,刺吸昆虫个体数量显著增加;转抗虫基因107杨节肢动物群落多样性指数、均匀度指数较高,优势度指数较低,节肢动物群落物种分布较均匀;相似性结果显示,物种组成与对照杨相似度较高;转抗虫基因107杨节肢动物群落物种间在数量上的制约作用较强;主成分分析表明食叶昆虫物种数量与个体数量、刺吸昆虫物种数量和其他植食性昆虫个体数量是影响转抗虫基因107杨与对照杨节肢动物群落变化的共同主导因子。     

矿区不同复垦措施对土壤碳矿化和酶活性的影响

矿区废弃地生态退化形势严峻,生态修复已成为矿区可持续发展的主要措施,目前关于矿区复垦后土壤碳矿化和酶活性变化的研究较少。以山西省孝义市露天矿区复垦区为研究对象,植被恢复类型包括了百脉根、苜蓿、油松和柳树-圆柏混交林,并对其分别进行不施肥(对照)、无机肥、复合肥和有机肥处理,从而研究植被类型与施肥方式对矿区土壤碳矿化和酶活性的影响。结果表明,乔本比草本恢复类型的土壤有机碳矿化潜势大,不同施肥条件的土壤有机碳矿化潜势和累积量趋势基本为:对照无机肥复合肥有机肥;4种土壤酶活性因植被恢复类型和施肥处理的不同而差异显著,不同土壤酶与降解特性不同的有机碳间相关性有所不同。土壤碳矿化累积量和酶活性均受植被恢复类型、施肥处理及两者交互作用的显著影响,因此对复垦措施敏感的土壤有机碳矿化和酶活性可作为评价复垦措施的指标。     

西双版纳热带季节雨林风时空变化特征初步分析

利用西双版纳热带季节雨林观测铁塔不同高度的风速及风向观测资料,分析了风的年、季节和日变化特征.结果表明,林冠上风速较强,林冠下风速较弱;林内风速的日变化和垂直变化均不明显.30～50 m范围内,风速垂直变化最显著,但年变化不大;50 m以上风速年变化显著,但垂直变化稍小.干热季(3～4月)风速最大,雨季(5～10月)次之,雾凉季(11～翌年2月)最小.昼间风速大于夜间.在昼间,上午风速最小,下午次之,中午最大.受地理位置和地形影响,风向具有明显的日变化特征,主导风向昼间为偏东南风,夜间为偏西风.昼间零平面位移(d) 值上午最大,中午次之下午最小,其年变化幅度呈现下午幅度大,上午和中午幅度小的趋势.粗糙度(Z₀)昼间值呈现下午>中午>上午的趋势,且下午Z₀值显著大于其他两个时段.     

大豆油中转基因成分的Nested PCR和Semi-nested PCR检测方法研究

对大豆油中DNA提取方法进行了研究,结果表明CTAB、SDS和Wizard试剂盒提取大豆油DNA均具有良好的效果。利用nested PCR和semi—nested PCR检测大豆（Roundup Ready）油中的转基因成分发现,该方法能够检测到大豆原油中的Lectin基因（112bp）、CaMV35S基因（147bP）和CP4-EPSPS基因（205bp）,检测灵敏度达到10^-6ng／μl;但该方法未能从人豆成品油（一级）中扩增到上述基因,当中的转基因成分DNA含量低于10^-12ng／μl。     

Sphingosine kinase regulates the sensitivity of Dictyostelium discoideum cells to the anticancer drug cisplatin

The drug cisplatin is widely used to treat a number of tumor types. However, resistance to the drug, which remains poorly understood, limits its usefulness. Previous work using Dictyostelium discoideum as a model for studying drug resistance showed that mutants lacking sphingosine-1-phosphate (S-1-P) lyase, the enzyme that degrades S-1-P, had increased resistance to cisplatin, whereas mutants overexpressing the enzyme were more sensitive to the drug. S-1-P is synthesized from sphingosine and ATP by the enzyme sphingosine kinase. We have identified two sphingosine kinase genes in D. discoideum--sgkA and sgkB--that are homologous to those of other species. The biochemical properties of the SgkA and SgkB enzymes suggest that they are the equivalent of the human Sphk1 and Sphk2 enzymes, respectively. Disruption of the kinases by homologous recombination (both single and double mutants) or overexpression of the sgkA gene resulted in altered growth rates and altered response to cisplatin. The null mutants showed increased sensitivity to cisplatin, whereas mutants overexpressing the sphingosine kinase resulted in increased resistance compared to the parental cells. The results indicate that both the SgkA and the SgkB enzymes function in regulating cisplatin sensitivity. The increase in sensitivity of the sphingosine kinase-null mutants was reversed by the addition of S-1-P, and the increased resistance of the sphingosine kinase overexpressor mutant was reversed by the inhibitor N,N-dimethylsphingosine. Parallel changes in sensitivity of the null mutants are seen with the platinum-based drug carboplatin but not with doxorubicin, 5-fluorouracil, and etoposide. This pattern of specificity is similar to that observed with the S-1-P lyase mutants and should be useful in designing therapeutic schemes involving more than one drug. This study identifies the sphingosine kinases as new drug targets for modulating the sensitivity to platinum-based drugs.     

Cell-type action specificity of auxin on Arabidopsis root growth

The plant hormone auxin plays a critical role in root growth and development; however, the contributions or specific roles of cell-type auxin signals in root growth and development are not well understood. Here, we mapped tissue and cell types that are important for auxin-mediated root growth and development by manipulating the local response and synthesis of auxin. Repressing auxin signaling in the epidermis, cortex, endodermis, pericycle or stele strongly inhibited root growth, with the largest effect observed in the endodermis. Enhancing auxin signaling in the epidermis, cortex, endodermis, pericycle or stele also caused reduced root growth, albeit to a lesser extent. Moreover, we established that root growth was inhibited by enhancement of auxin synthesis in specific cell types of the epidermis, cortex and endodermis, whereas increased auxin synthesis in the pericycle and stele had only minor effects on root growth. Our study thus establishes an association between cellular identity and cell type-specific auxin signaling that guides root growth and development.     

RADtyping: An Integrated Package for Accurate De Novo Codominant and Dominant RAD Genotyping in Mapping Populations

Genetic linkage maps are indispensable tools in genetic, genomic and breeding studies. As one of genotyping-by-sequencing methods, RAD-Seq (restriction-site associated DNA sequencing) has gained particular popularity for construction of high-density linkage maps. Current RAD analytical tools are being predominantly used for typing codominant markers. However, no genotyping algorithm has been developed for dominant markers (resulting from recognition site disruption). Given their abundance in eukaryotic genomes, utilization of dominant markers would greatly diminish the extensive sequencing effort required for large-scale marker development. In this study, we established, for the first time, a novel statistical framework for de novo dominant genotyping in mapping populations. An integrated package called RADtyping was developed by incorporating both de novo codominant and dominant genotyping algorithms. We demonstrated the superb performance of RADtyping in achieving remarkably high genotyping accuracy based on simulated and real mapping datasets. The RADtyping package is freely available at http://www2.ouc.edu.cn/mollusk/ detailen.asp?id=727.     

Protective effect of coumarin-pi against t-BHP-induced hepatotoxicity by upregulating antioxidant enzymes via enhanced Nrf2 signaling

Molecular and Cellular Biochemistry - Autism is a prevalent developmental disorder that combines repetitive behaviours, social deficits and language abnormalities. The present study aims to assess...     

Molecular dynamics simulation of the Al2O3 film structure during atomic layer deposition

Based on an understanding of atomic layer deposition (ALD) from prior experimental and computational results, all-atom molecular dynamics (MD) simulations are used to model the Al₂O₃ film structure and composition during ALD processing. By separating the large time-scale surface reactions from the small time-scale structural relaxation, we have focused on the growth dynamics of amorphous Al₂O₃ films at the atomic scale. The simulations are able to reproduce some important properties and growth mechanisms of Al₂O₃ ALD films, and hence provide a bridge between atomic-level information and experimental measurements. Information about the evolution of the microscopic structures of the Al₂O₃ films is generated, and the influence of operation parameters on the Al₂O₃ ALD process. The simulations predict a strong influence of the initial surface composition and process temperature on the surface roughness, growth rate and growth mode of the deposited films.     

C-Terminal Membrane Association of Bestrophin 3 and Its Activation as a Chloride Channel

Bestrophin 3 (Best3), a member of the bestrophin Cl^? channel family, is a candidate of cGMP-sensitive, Ca²⁺-activated Cl^? channel in vascular smooth muscle cells. The Best3 channel was recently found to play an important role in vasomotion. However, the mechanism for its activation has not been clarified. In previous studies, we found that a Best3 C-terminal sequence (amino acids 353–404) was associated with the cellular membrane. The sequence includes an autoinhibitory domain (³⁵⁶IPSFLGS³⁶²) and a downstream basic residue domain (amino acids 384–397). In this study, we found that the sequence (368–383) between the two domains is actually a determinant for Best3 C-terminal membrane associability. Deletion of the sequence almost abolished the membrane association but did not activate the Best3 channel. Treatment of Best3-expressing HEK293 cells with the PI3Kα inhibitor IV (a Best3 activator) could not abolish but weakened the Best3 membrane association. The result supports the assumption that the positively charged basic residues in the Best3 C terminus are likely associated with the membranous negatively charged phospholipids, which plays a role in the regulation of Best3 activation. But the relationship between membrane associability and Best3 activation seems more complicated than expected.