Fe Chelates for Remediation of Fe Chlorosis in Strategy I Plants

Abstract

Iron chlorosis is a mineral disorder due to low Fe in the soil solution and the impaired plant uptake mechanism. These effects increased with high pH and bicarbonate buffer. The solution to Fe chlorosis should be made by either improving the Fe uptake mechanism or increasing the amount of Fe in the soil solution. Among Fe fertilizers, only the most stable chelates (EDDHA and analogous) are able to maintain Fe in the soil solution and transport it to the plant root. In commercial products with the same chelating agent, the efficacy depends on the purity and the presence of subproducts with complexing activity, that can be determined by appropriate analytical methods such as HPLC. In commercial products declaring 6% as Fe‐EDDHA, purity varied from 0.5% to 3.5% before 1999, but in 2002 products ranging 3–5.4% chelated Fe are common in the Spanish market. Fe‐o,p‐EDDHA, as a synthesis by‐product with unknown efficacy, is present in all Fe‐EDDHA formulations. Commercial Fe‐EDDHMA products also contain methyl positional isomers. Fe‐EDDHSA synthesis produces condensation products with similar chelating capacity to the Fe‐EDDHSA monomer that can account for more than 50% of the chelated iron in the commercial products. Chelates with different molecules should be compared for their efficacy considering firstly their ability to maintain Fe in solution and secondly their capacity to release iron to the roots. Accepting the turnover hypothesis, their efficacy is also dependent thirdly on the ability of the chelating agent to form the chelate using native iron from the soil. The 1st and 3rd points are related to the chemical stability of the chelate, while plants make better use of iron from the less stable chelates. Plant response is the ultimate evaluation method to compare commercial products with the same chelating agent or different chelates.     

密闭电石炉尾气中羰基硫的气相色谱测定法

[目的]建立密闭电石炉尾气中羰基硫（COS）检测的气相色谱法。[方法]用100ml玻璃注射器采集COS气体,注入HC-6型微量磷硫气相色谱分析仪,经GDX-104色谱柱分离后,应用火焰光度气相色谱法进行检测。[结果]该方法的线性检测范围为0.0003～2.0000mg/m^3,线性方程为y=36.7020＋2.2632x（R=0.99959）,RSD为2.10%～4.79%,最低检出限为0.0003mg/m3。[结论]该方法快捷、灵敏度高、结果准确、稳定性好,适合密闭电石炉尾气中COS的测定。     

犬血浆中托芬那酸高效液相色谱检测法的建立

为了建立高效液相色谱(HPLC)法测定地犬血浆中托芬那酸的含量,采用Agilent ZORBAX Eclipse Plus C18(250 mm×4.6 mm,5μm)色谱柱,流动相使用甲醇∶乙腈∶0.05 M醋酸钠(p H=4.6)为36.5∶36.5∶27,流速为0.7 m L/min,柱温为35℃,检测波长为290 nm。结果:托芬那酸的血浆药物浓度在0.05~10.0μg/m L范围内,线性关系良好(r=0.9993);最低检出限为0.025μg/m L;定量限为0.05μg/m L,平均回收率为85%,批内和批间系数分别小于11%和6%。本方法简便准确、快速可靠,适用于犬血浆中托芬那酸的药动学和相对生物利用度研究。     

Application of molecular recognition theory in thyrotropin and its receptor system

AIM: The selective recognition of the sense peptides which are located in special regions of thyrotropin receptor (TSHR) by their corresponding antisense peptides has been investigated. Three pairs of sense and antisense peptides were named TR1 (aa37-45) and RT1 (aa45-37), TR2 (aa353-366) and RT2 (aa366-353), TR3 (aa648-655) and RT3 (aa655-648). METHODS: To prepare three affinity chromatography columns, antisense peptides were immobilized, called RT1-sepharose 4B, RT2-sepharose 4B and RT3-sepharose 4B, respectively and investigate the retardative behavior for each of native peptide TR1, TR2 or TR3 on above columns with stepwise elution. RESULTS: Each of the three immobilized antisense peptides recognized and retarded its corresponding sense peptide-TR1, TR2 or TR3 instead of those non-complementary peptides. Immobilized RT1 recognized free TSHR protein molecule as well. In additional, bovine thyrotropin was recognized by immobilized TR1. CONCLUSION: The results indicate that molecular recognition theory exsits in thyrotropin receptor system. It may be useful to isolate biological molecules and to locate epitopes of TSH on TSHR molecule. Otherwise, antisense peptide may be used for treatment of experimental autoimmunolized thyroid disease (AITD) in the rat.     

大豆紫斑病菌毒素研究

 大豆紫斑病菌(Cercospora Kikuchii Matsumoto and Tomoyasu)可产生一种非专化毒素——尾孢毒素(Cercosporin),它是大豆紫斑病致病的重要因子。该菌PDA培养物经乙醇浸提、脱水磷酸氢钙柱层析可得一定纯度尾孢毒素。本文分析了该毒素紫外可见光谱吸收与高效液相(HPLC)鉴定结果。生物活性测试表明,该毒素具有明显的光敏致毒活性。     

冬杜鹃花新品种‘雪中笑’与双亲关系的探讨

新近育成的能在寒冬连续开花三个月的冬杜鹃花新品种——‘雪中笑’,具有一系列优良性状。通过用聚酰胺薄膜层析法来比较‘雪中笑’及其双亲叶片、花冠所含黄酮类等化合物的种类,结果证明,杂种与双亲所含黄酮类等化合物种类呈密切相关,‘雪中笑’确系映山红R.simsii与‘月白风清’的人工杂交种。     

气相色谱法测定水中硝基苯的不确定度评估简

[目的]评估气相色谱法测定水中硝基苯的不确定度。[方法]依据GB／T13194—1991用气相色谱法对水中硝基苯的舍量进行测定,全面系统地分析了影响其测定的不确定度的各种因素,建立了测量过程中各分量的数学模型,估算各不确定度分量对总不确定度的影响,确定测量结果的包含区间。[结果]试验得出,标准溶液配置过程是影响气相色谱法测定水中硝基苯的不确定度的主要因素,仪器重复测定带来的不确定度可以忽略不计。[结论]研究得出的对测定结果不确定度影响的主要因素,在测定时应该予以重视。     

肌注手足口病(EV71型)人免疫球蛋白层析工艺研究

[目的]优化手足口病（EV71型）人免疫球蛋白的层析工艺条件,为制备治疗手足口病（Ev71型）的人免疫球蛋白提供依据。[方法]采用单因素试验和响应面分析法,研究样品pH值、蛋白质浓度和电导率对层析后流穿液中免疫球蛋白纯度的影响。[结果]影响层析流穿液中免疫球蛋白纯度的主要因素为电导率,其次是蛋白质浓度,pH值对层析流穿液中免疫球蛋白蛋白纯度影响最小。手足口病（EV71型）人免疫球蛋白的最佳层析工艺参数为：pH5．28、蛋白质浓度41．62g／L、电导率为0．24m／s。[结论]层析优化后的流穿液中手足口病（EV71型）人免疫球蛋白纯度可达到99．60％,可用于制备高纯度的手足口病（EV71型）人免疫球蛋白。     

固相萃取-高效液相色谱法同时检测奶牛粪污中5种磺胺类抗生素

建立的固相萃取-高效液相色谱法具有灵敏度高、检测限低的特点,可同时定量检测奶牛粪污中磺胺嘧啶、磺胺二甲嘧啶、磺胺间甲氧嘧啶、磺胺甲恶唑、磺胺喹噁啉的残留。采用C18色谱柱(500 mm×4.6 nm, 5μm),以0.3%的乙酸-乙腈溶液为流动相,在流速1.0 mL/min、检测波长270 nm、柱温30℃条件下,5种抗生素均能达到基线分离;3倍信噪比下,5种抗生素的检出限均为20μg/kg。在加标浓度50μg/kg条件下,奶牛粪污样品经前处理、MCX固相萃取小柱富集净化后,五种磺胺类抗生素回收率达到75%～80%,相对标准偏差为2.8%～3.9%。此方法检测了某规模化奶牛场粪污中磺胺类抗生素残留,结果显示,磺胺嘧啶的浓度范围在45～50μg/kg,其他抗生素无检出。     

双峰驼精清诱导排卵活性因子的HPLC分离纯化及生物活性测定

利用C8柱经HPLC对QHyper D柱分离的驼精清活性组分F3和F5进行分离纯化，大鼠垂体组织培养，RIA测定培养液中LH和FSH的浓度。实验结果表明，F3和F5经过HPLC纯化后，各得到4个组分，分别以F3－1－F3－4和F5－1－F5－4表示。其中F3-3和F5－3可引起体外培养的大鼠垂体LH的释放显著增加，但均未引起FSH发生明显变化。用C18柱经HPLC或毛细管电泳对F3－3进一步纯化，无论在HPLC或毛细管电泳仪中，F3－3均呈现两个波峰，而且间隔非常靠近，说明F3－3至少是由两种分子特征非常相似的物质组成。