Rapid enzyme-linked immunosorbent assay and colloidal gold immunoassay for kanamycin and tobramycin in Swine tissues     

Chen Y  Wang Z  Wang Z  Tang S  Zhu Y  Xiao X 《Journal of agricultural and food chemistry》2008,56(9):2944-2952

A monoclonal antibody (Mab) was produced by using the kanamycin-glutaraldehyde-bovine serum albumin (Kan-GDA-BSA) conjugate as the immunogen. The anti-Kan Mab exhibited high cross-reactivity with tobramycin (Tob) and slight or negligible cross-reactivity with other aminoglycosides. The specificity and cross-reactivity of this Mab are discussed regarding the three-dimensional, computer-generated molecular models of the aminoglycosides. Using this Mab, a rapid enzyme-linked immunosorbent assay (ELISA) and a colloidal gold-based strip test for Kan and Tob were developed. The rapid ELISA showed a 50% inhibition value (IC 50) of 0.83 ng/mL for Kan and 0.89 ng/mL for Tob with the analysis time less than 40 min, and the recoveries from spiked swine tissues at levels of 25-200 microg/kg ranged from 52% to 96% for Kan and 61% to 86% for Tob. In contrast, the strip test for Kan or Tob had a visual detection limit of 5 ng/mL in PBS, 50 microg/kg in meat or liver, and 100 microg/kg in kidney, and the results can be judged within 5-10 min. Observed positive samples judged by the strip test can be further quantitated by ELISA, hence the two assays can complement each other for rapid detection of residual Kan and Tob in swine tissues. Moreover, physical-chemical factors that affected the ELISA and strip test performance were also investigated. The effect of pH and antibody amount for gold-antibody conjugation on the strip test sensitivity was determined followed by a theoretical explanation of the effects.  相似文献   

Revealing the metabonomic variation of rosemary extracts using 1H NMR spectroscopy and multivariate data analysis     

Xiao C  Dai H  Liu H  Wang Y  Tang H 《Journal of agricultural and food chemistry》2008,56(21):10142-10153

The molecular compositions of rosemary ( Rosmarinus officinalis L.) extracts and their dependence on extraction solvents, seasons, and drying processes were systematically characterized using NMR spectroscopy and multivariate data analysis. The results showed that the rosemary metabonome was dominated by 33 metabolites including sugars, amino acids, organic acids, polyphenolic acids, and diterpenes, among which quinate, cis-4-glucosyloxycinnamic acid, and 3,4,5-trimethoxyphenylmethanol were found in rosemary for the first time. Compared with water extracts, the 50% aqueous methanol extracts contained higher levels of sucrose, succinate, fumarate, malonate, shikimate, and phenolic acids, but lower levels of fructose, glucose, citrate, and quinate. Chloroform/methanol was an excellent solvent for selective extraction of diterpenes. From February to August, the levels of rosmarinate and quinate increased, whereas the sucrose level decreased. The sun-dried samples contained higher concentrations of rosmarinate, sucrose, and some amino acids but lower concentrations of glucose, fructose, malate, succinate, lactate, and quinate than freeze-dried ones. These findings will fill the gap in the understanding of rosemary composition and its variations.  相似文献   

Chemical kinetic behavior of chlorogenic acid in protecting erythrocyte and DNA against radical-induced oxidation     

Tang YZ  Liu ZQ 《Journal of agricultural and food chemistry》2008,56(22):11025-11029

As an abundant ingredient in coffee, chlorogenic acid (CGA) is a well-known antioxidant. Although some works have dealt with its radical-scavenging property, the present work investigated the protective effects of CGA on the oxidation of DNA and on the hemolysis of human erythrocytes induced by 2,2'-azobis(2-amidinopropane hydrochloride) (AAPH) by means of chemical kinetics. The inhibition period (t(inh)) derived from the protective effect of CGA on erythrocyte and DNA was proportional to its concentration, t(inh) = (n/R(i))[CGA], where R(i) refers to the radical-initiation rate, and n indicates the number of radical-propagation chains terminated by CGA. It was found that the n of CGA to protect erythrocytes was 0.77, lower than that of vitamin E (2.0), but higher than that of vitamin C (0.19). Furthermore, CGA facilitated a mutual protective effect with VE and VC on AAPH-induced hemolysis by increasing n of VE and VC. CGA was also found to be a membrane-stabilizer to protect erythrocytes against hemin-induced hemolysis. Moreover, the n of CGA was only 0.41 in the process of protecting DNA. This fact revealed that CGA served as an efficient antioxidant to protect erythrocytes more than to protect DNA. Finally, the reaction between CGA and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate) radical cation (ABTS(+*)) or 2,2'-diphenyl-1-picrylhydrazyl (DPPH) revealed that CGA was able to trap radicals by reducing radicals more than by donating its hydrogen atoms to radicals.  相似文献   

Input–Output Budgets for Inorganic Nitrogen Under Acid Rain in a Subtropical Evergreen Mixed Forest in Central-South China     

C. Y. Du  G. M. Zeng  G. Zhang  L. Tang  X. D. Li  D. L. Huang  L. Huang  Y. M. Jiang 《Water, air, and soil pollution》2008,190(1-4):171-181

Inorganic nitrogen deposition and leaching in stream water were monitored from January, 2001 to December, 2004 in a subtropical evergreen mixed forest in central-south China. The seasonal concentration and flux of inorganic nitrogen in bulk precipitation and stream water, seasonal mean net retention of nitrogen and net flux of H⁺ transformed by nitrogen were estimated and quantified in Shaoshan forest. The research results show that the correlation coefficient of fluxes between bulk precipitation and stream water is significant, with a coefficient 0.916 at the 0.01 level. Mean fluxes of inorganic nitrogen input are 2.62 g m^?2 a^?1 and 0.516 g m^?2 a^?1 in form of bulk precipitation and dry deposition respectively, and output in stream water is around 0.22 g m^?2 a^?1, which indicates that most of nitrogen input is reserved in the forest. Net retention of nitrogen reaches 2.916 g m^?2 a^?1, just higher than other study plots over the world. Along with the translating of nitrogen ( ${\text{NH}}_4^ + - {\text{N}}$ and ${\text{NO}}_3^ - - {\text{N}}$ ), H⁺ is imported to the forest ecosystem at the same time. At our study plots, net flux of H⁺ transformed by nitrogen is about 73.57 mmol m^?2 a^?1. The positive value suggests that Shaoshan forest is still a finer buffering system to nitrogen deposition and it is far from nitrogen saturation in spite of the high nitrogen deposition.  相似文献   

Soil development along primary succession sequences on moraines of Hailuogou Glacier,Gongga Mountain,Sichuan, China   总被引：1，自引：0，他引：1  

Lei He  Ya Tang 《CATENA》2008

Soil properties related to soil development were measured in six profiles over approximately 180 years of soil development on recessional moraines of the Hailuogou Glacier, Sichuan of southwestern China. It is hypothesized that soil development is strictly time-dependent. Field and laboratory work indicate that as soil develops from initially coarse gravel outwash, the properties undergo a progressive physical and chemical change such that there is a considerable profile differentiation between the youngest and the oldest soils. The pH is also highly stratified; it decreases with time from 8.5 to 4.2 in the upper mineral soil and increases with depth in all profiles. Accumulation of soil organic C and N increases with time but the rates of accumulation become slower with time. Within the investigated timespan, soil C and N accumulated to a considerable level of 3.5 and 0.6 kg/m² respectively, with mean annual rates of 28 g/m² for carbon and 3.5 g/m² for nitrogen. The rapid accumulation of organic C and N accelerates the processes of soil formation, but the content of organic C and N did not reach a steady-state during the observed timespan. The accumulation of soil organic matter results in increased acid production and in the chemical weathering of minerals that promote formation and translocation of the clay fraction and leaching of carbonate; it is also directly responsible for development of soil properties such as cation exchange capacity (CEC), and bulk density.  相似文献   

聚合物包膜肥料铵态氮释放特征研究   总被引：2，自引：0，他引：2  

汤德源  杜昌文  王火焰  周健民  AviShaviv 《土壤学报》2008,45(2):274-279

采用单一组分与复合组分的聚合物包膜肥料,利用静态水溶出的方法研究了不同温度和半径处理下,聚合物包膜肥料铵态氮释放特征。结果表明,养分释放显著受到温度、颗粒半径的影响,温度越高,半径越小,养分释放速度越快,且发现养分释放特征与肥芯的化合物组成有关,肥芯化合物组成不同造成各种离子的饱和浓度发生变化,影响了跨膜释放的动力从而影响释放。养分释放的滞后期和线性期也随温度的升高和颗粒半径的缩小而缩短,且肥芯化合物组成也通过影响离子的饱和浓度影响了养分释放的滞后期和线性期。利用养分释放活化能来反映养分释放速度变化随温度变化的敏感程度。试验结果表明,活化能与颗粒半径、肥芯化合物组成有关。通过对活化能和养分释放三阶段的描述能更全面地反映包膜肥料养分释放与作物养分需求的协调性,为包膜肥料的研制和应用提供了新的思路。  相似文献   

基于GIS的县域耕地测土配方施肥技术研究   总被引：9，自引：5，他引：4  

唐秀美  赵庚星  路庆斌 《农业工程学报》2008,24(7):34-38

该文以山东广饶县为例,进行了面向管理层面的县域耕地测土配方施肥技术研究.在耕地地力调查分析数据及其地力评价的基础上,采用GIS支持下的"地力分区 目标产量法"确定区域施肥配方.以耕地地力等级图和作物布局图叠加的方法划分配方单元,通过田间试验得到各种参数,通过GIS将配方单元图与相应属性数据模型的联结,采用养分平衡法计算各养分需要量和施肥配方.结果显示,广饶县耕地氮、磷、钾养分含量空间分布差异较大,得到的施肥配方种类较多,全县共有14种施肥配方,其中氮磷钾配方比例分布在1:0.04～1.53:0.05～0.82之间.该研究较好地探索了基于GIS的县域耕地测土配方施肥技术方法,对县域耕地利用和施肥管理工作有积极的指导作用.  相似文献   

苗木嫁接机器人切削机构模拟试验   总被引：6，自引：6，他引：0  

李明  戴思慧  汤楚宙  向阳 《农业工程学报》2008,24(6):129-132

为研究满足苗木嫁接机要求的切削机构,设计了半旋转切削机构并优化其结构参数.选取桃、李、柑橘、葡萄和板栗五种嫁接幼苗作为试验对象,在模拟切削试验装置上进行了切削模拟试验.试验结果检验该半旋转切削机构的可行性及分析得出了影响切削阻力试验指标和切削成功率试验指标的主、次试验因素.研究表明影响苗木切削的因素:苗木平均直径、转速、滑切角分别与切削阻力和切削成功率的相关性.综合得出,该半旋转切削机构是可行的;苗木直径、转速和滑切角分别较大地影响切削阻力和切削成功率,苗木直径是主要影响因素,实行工厂化育苗来有效保证苗木直径大小和均匀性;转速调节范围50～60 r/min,滑切角调整略人于30°.  相似文献   

大沟控制排水对地下水水位影响研究   总被引：2，自引：2，他引：0  

王友贞  王修贵  汤广民 《农业工程学报》2008,24(6):74-77

控制排水技术是调控农田水资源的主要措施.该文采用原型观测与模拟模型相结合的研究方法,在平原区农田排水大沟设置控制设施的大型观测试区,研究其对地下水的调控效果;利用三维地下水流运动模拟模型,进行了不同控制条件下田间地下水的动态模拟,获得不同控制方案的优化结果.研究结果表明:排水大沟加设控制设施可有效避免地下水资源的流失,有利于作物对地下水的利用.该研究对农田水资源的调控和控制排水工程建设有参考价值.  相似文献   

单缸LPG发动机性能和工作过程（简报）   总被引：1，自引：1，他引：0  

王建  刘胜吉  汤东 《农业工程学报》2008,24(9):111-114

为了弄清以ZSI 100柴油机为基础开发的单缸液化石油气发动机的工作原理,以利于进一步改进,以试验和模拟计算结合的方法,研究了该机的动力性能和工作过程.通过LPG与窄气混合器参数优选、燃烧系统参数设计及点火提前角控制等技术措施,优化了单缸LPG发动机的性能.性能试验结果表明,样机在安装点火提前装置后,取得了良好的整机性能.通过放热规律模型的建立、计算结果的分析,对柴油机燃用LPG后其工作过程的进行和组织有更直观和清晰的理解,对柴油机燃用LPG的改装应用提供参考依据.  相似文献