Kinetics of Hg adsorption onto noncrystalline Al hydroxide as influenced by low-molecular-weight organic ligands     

Jae E. Yang  Yong Sik Ok 《Archives of Agronomy and Soil Science》2017,63(1):124-135

This study was conducted to investigate the kinetics of Hg adsorption by noncrystalline Al hydroxide as influenced by various pH conditions and cysteine (cys), glycine (gly), and citric acid (cit), which have different structures and functionalities, as low-molecular-weight organic ligands using the GEOCHEM-PC software. The influence of these organic ligands on the kinetics of Hg adsorption varied according to their concentration, structure, and functionality and pH. The adsorption of Hg followed multiple first order kinetics with initial rapid adsorption, followed by slow adsorption. Cysteine suppressed or enhanced Hg adsorption, depending on pH and its concentration. Glycine and citric acid exerted suppressing and enhancing effects, respectively, with the exception of at pH 4.5 and at lower concentrations, at which no influence was observed as compared to the control. Two mechanisms were thought to mediate the adsorption of Hg(II); specific surface complexation in the control, cysteine and glycine systems, and ligand exchange in the citric acid system. The Hg adsorption at all levels of organic ligands decreased with increasing pH, with the exception of at the higher concentration of cysteine, at which the reverse trend was observed. The influence of organic ligands on the dynamics of Hg in the freshwater environment merits further study.  相似文献   

基于CO II全基因的差翅亚目昆虫分子系统学研究     

张晓洁  查岭生 《安徽农业科学》2010,38(5):2264-2267

[目的]对基于CO Ⅱ全基因的差翅亚目昆虫的分子系统学进行研究。[方法]设计蜻蜓目昆虫CO Ⅱ全基因的非特异性引物,获得差翅亚目5科6属8种共8条CO Ⅱ全序列。采用CluxtalX1.8、ContigExpress、MEGA2.1、PHYLIP3.6a以及MrBayes V3.0等生物学软件及简约法和最大似然法对其进行分析并构建分子系统树。[结果]CO Ⅱ的A＋T含量较低（68.6%）,说明蜻蜓目是一比较原始的类群;每条序列均含有2个半胱氨酸,这一点有别于其他类群昆虫;不支持将大蜻亚科上升为科的观点;支持将大蜓科和蜓科归入蜓总科,而将春蜓科上升为总科的观点;差翅亚目5科之间的进化关系由慢到快依次为：春蜓科→大蜓科→蜓科→伪蜻科→蜻科。[结论]为蜻蜓目分子系统学研究提供相关依据。  相似文献   

Evaluation of type I fusarium head blight resistance of wheat using non-deoxynivalenol-producing fungi     

N. Gosman†  Srinivasachary  A. Steed  E. Chandler  M. Thomsett  P. Nicholson 《Plant pathology》2010,59(1):147-157

A series of experiments was conducted to determine whether type I resistance (resistance to initial infection) to fusarium head blight (FHB) in wheat could be assessed using fungal species/isolates that do not produce deoxynivalenol (DON), a mycotoxin critical to the spread of Fusarium graminearum in the wheat spike. It was shown that, while the non-toxin-producing species Microdochium nivale and M. majus could infect following spray inoculation of wheat spikes, they were unable to spread within the spike following point inoculation. However, although these species might reveal type I resistance, they are not highly pathogenic towards wheat. A nivalenol (NIV)-producing isolate of F. graminearum caused high levels of disease following spray inoculation, but spread only very slowly within the spike and rarely induced bleaching above the point of inoculation. It is proposed that spray inoculation with an appropriate, aggressive, non-DON-producing FHB pathogen may be used to characterize type I resistance to complement point inoculation with a DON-producing isolate to assess type II resistance (resistance to spread within the spike).  相似文献   

Effects of insecticide acetamiprid on photosystem II (PSII) activity of Synechocystis sp. (FACHB-898)     

Li. Li  Xi. Chen  Daoyong Zhang  Xiangliang Pan 《Pesticide biochemistry and physiology》2010,98(2):300-304

Effects of insecticide acetamiprid on photosystem II (PSII) activity of Synechocystis sp. were investigated by a variety of in vivo chlorophyll fluorescence tests. Acetamiprid exposure increased the proportion of inactivated PSII reactive centers (PSII_X) and led to loss of active centers (PSII_A). High concentration (1.0 mM) acetamiprid decreased amplitude of the fast phase and increased the slow phase of fluorescence decay during reoxidation. The electron transport after Q_A was hindered by high concentration acetamiprid and more Q_A had to be reoxidized through S₂(Q_AQ_B)⁻ charge recombination. Acetamiprid decreased the density of the active reaction centers, electron transport flux per cross section and the performance of PSII activity but had little effect on dissipated energy flux per reaction center, antenna size and the maximum quantum yield for primary photochemistry (F_v/F_m). The target site of acetamiprid toxicity to the PSII of Synechocystis sp. was electron transfer on the acceptor side.  相似文献   

Ⅱ优航148示范表现与高产栽培技术     

游晴如  杨东  黄庭旭  郑家团  张水金  涂诗航  董瑞霞  王乌齐  谢华安 《福建稻麦科技》2010,28(4):33-36

阐述了杂交籼稻新品种Ⅱ优航148在各地示范种植的表现,并从适时播种、培育壮秧、合理密植、肥水管理、病虫害防治等方面介绍其高产栽培技术。  相似文献   

Hsp70 enhances presentation of FMDV antigen to bovine CD4+ T cells in vitro     

Kerry McLaughlin  Julian Seago  Lucy Robinson  Charles Kelly    Bryan Charleston 《Veterinary research》2010,41(3)

Foot-and-mouth disease virus (FMDV) is the causative agent of a highly contagious acute vesicular disease affecting cloven-hoofed animals, including cattle, sheep and pigs. The current vaccine induces a rapid humoral response, but the duration of the protective antibody response is variable, possibly associated with a variable specific CD4⁺ T cell response. We investigated the use of heat shock protein 70 (Hsp70) as a molecular chaperone to target viral antigen to the Major Histocompatibility Complex (MHC) class II pathway of antigen presenting cells and generate enhanced MHC II-restricted CD4⁺ T cell responses in cattle. Monocytes and CD4⁺ T cells from FMDV vaccinated cattle were stimulated in vitro with complexes of Hsp70 and FMDV peptide, or peptide alone. Hsp70 was found to consistently improve the presentation of a 25-mer FMDV peptide to CD4⁺ T cells, as measured by T cell proliferation. Complex formation was required for the enhanced effects and Hsp70 alone did not stimulate proliferation. This study provides further evidence that Hsp70:peptide complexes can enhance antigen-specific CD4⁺ T cell responses in vitro for an important pathogen of livestock.  相似文献   

The Effects of Forced Exercise on Collagen Type II Fragments,Lysyl Oxidase Concentrations,and Total Protein Concentrations in Sera and Synovial Fluid of Lambs     

Kristine L. Vernon  Laura Riggs  Josie Coverdale  Ashbey Budd Bodine  John Gibbons 《Journal of Equine Veterinary Science》2010

Excessive exercise may induce osteoarthritis, which is a leading cause of lameness and decreased use in horses. The purpose of this study was to utilize a sheep model to determine the effects of circular and linear exercise on biochemical markers in serum and synovial fluid (SF). Twenty lambs (5 months) were assigned to three groups: circular exercise (C, 8.5 m diameter; n = 8), straight-line exercise (S, treadmill; n = 8) and nonexercised control (CON, n = 4). Lambs (C and S) were exercised up to 8 weeks at 1.3 m/s for up to 30 minutes, 6 days per week. Serum and SF from a metacarpophalangeal (MCP) joint was collected. Serum total protein (P = .66), Collagen Type II cleavage [3/4] fragments concentrations (P = .44) and lysyl oxidase (LOX) (P = .15) activity were not different among treatment groups throughout the study. There was a polynomial response to serum LOX over time (R² = 0.7464). There were no differences in SF total protein (P = .94, right MCP; P = .68, left MCP) or SF LOX specific activities (P = .9, right MCP; P = .93, left MCP) among groups throughout the study. However, SF LOX specific activity did increase over time (P = .001) for all treatment groups. These results indicated that the biochemical markers utilized in this study were unable to detect differences between groups with respect to exercise protocols. However, the LOX activity did increase over time possibly as a result of growth.  相似文献   

不同地理种群灰飞虱基于Co Ⅱ基因的系统发育分析     

季英华  史文琦  乐文静  刘莉  周益军 《江苏农业学报》2010,26(3)

对9个灰飞虱地理种群的Co Ⅱ(Cytochrome oxidase Ⅱ基因进行克隆测序,并提交GenBank(EU728817～EU728826)。序列分析结果显示:不同灰飞虱地理种群的Co Ⅱ基因同源性非常高(99%以上),且无明显的种群差异;而灰飞虱和白背飞虱的Co Ⅱ基因的同源性相对较低(约80%),表现出了种间差异,表明Co Ⅱ基因可能不适合用于研究灰飞虱地理种群的划分,同时也说明Co Ⅱ基因较适合用于亲缘关系较近的种间系统发育研究。  相似文献   

一类具有HollingII型功能性反应的捕食者-食饵系统正周期解的存在性     

杜明银  雒志学 《吉林林学院学报》2010,(1):19-23

研究了一类具HollingII型功能性反应的捕食者一食饵系统非平凡周期解的存在性,其中捕食者种群具有密度制约,食饵种群服从Hallam增长,得到了存在正周期解的充分性条件．  相似文献   

硒对低温胁迫下番茄幼苗叶片光合特性与叶绿素荧光参数的影响   总被引：3，自引：1，他引：2  

张彩虹  刘慧英  于秀针 《中国农学通报》2010,26(5):152-157

以加工番茄‘里格尔87-5’幼苗为试材,对其外施0.3、0.6、0.9、1.2mgSe? kg-1Na2SeO3的溶液,并进行昼(12±1)℃/夜(8±1)℃的低温胁迫处理。研究硒对低温胁迫下加工番茄幼苗叶片光合作用及叶绿素荧光参数的影响。结果表明：随着低温胁迫时间的延长,番茄幼苗叶片净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)和胞间CO2浓度(Ci)减小;叶片初始荧光(Fo)、非光化学荧光猝灭系数(qN)上升;最大荧光(Fm)、PSⅡ最大光化学效率(Fv/Fm)、PSⅡ潜在活性(Fv/Fo)、光化学猝灭系数(qP)表现下降。不同浓度的硒溶液可以缓解低温胁迫对番茄幼苗光合作用和叶绿素荧光参数的影响,并且以0.9mgSe?kg-1Na2SeO3 的作用效果最好。  相似文献