高效除磷工程菌Pseudomonas putida GM6-PPK1的构建及其除磷能力研究

ppk1 基因编码的多聚磷酸盐激酶主要负责多聚磷酸盐的合成,其表达量的高低直接决定聚磷菌的聚 P 能力的强弱.Pseudomonas putida GM6 是从 EBPR 好氧池活性污泥中分离获得的一株具有聚 P 能力的菌株,该菌株含有两个编码多聚磷酸盐激酶的基因(ppk1 和 ppk2).通过 PCR 从高效聚磷菌株总 DNA 中扩增得到了 ppk1 及其启动子,并定向克隆到 pBBRMCS-5 载体上,构建了重组质粒 pMEPE-PPK,在辅助质粒 pRK2013 的帮助下,通过三亲接合将 pMEPE-PPK 转移到原始菌株 GM6 中,获得的工程菌 P. putida GM6-PPK1.GM6-PPK1 除 P 能力较原始菌株 GM6 和对照菌株 GM6-P5 提高了 54%,生长能力较原始菌株也有一定增强.通过模拟 EBPR 工艺,发现 GM6-PPK1 在厌氧/好氧交替的环境条件下强化表达不但提高了菌体好氧段的吸 P 能力,而且厌氧段 P 的释放和 PHA 的合成较之原始菌株也有显著增加.     

一种基于数字高程模型的流域边界提取修正方法

Boundary extraction of watershed is an important step in forest landscape research. The boundary of the upriver watershed of the Hunhe River in the sub-alpine Qingyuan County of eastern Liaoning Province, China was extracted by digital elevation modeling (DEM) data in Arclnfo8.1. Remote sensing image of the corresponding region was applied to help modify its copy according to Enhanced Thematic Mapper (ETM) image‘s profuse geomorphological structure information. Both the DEM-dependent boundary and modified copy were overlapped with county map and drainage network map to visually check the effects of result. Overlap of county map suggested a nice extraction of the boundary line since the two layers matched precisely,which indicated the DEM-dependent boundary by program was effective and precise. Further upload of drainage network showed discrepancies between the boundary and the drainage network. Altogether, there were three sections of the extraction result that needed to correct. Compared with this extraction boundary, the modified boundary had a better match to the drainage network as well as to the county map. Comprehensive analysis demonstrated that the program extraction has generally fine precision in position and excels the digitized result by hand. The errors of the DEM-dependant extraction are due to the fact that it is difficult for program to recognize sections of complex landform especially altered by human activities, but these errors are discernable and adjustable because the spatial resolution of ETM image is less than that of DEM. This study result proved that application of remote sensing information could help obtain better result when DEM method is used in extraction of watershed boundary.     

多环芳烃污染土壤生物联合强化修复研究进展

多环芳烃(polycyclic aromatic hydrocarbons,PAHs)是广泛存在于环境中的一类有毒有机污染物。在PAHs污染土壤修复领域中,运用一些生物化学的方式来强化生物联合修复技术可以有效缩短生物修复的时间,大大提高修复效率,最具发展前景和应用价值。本文主要以植物-微生物、植物-微生物-土壤动物两种生物联合修复方式为对象,结合各自的特点、机理和实例,推断了其修复机制的内在原因,总结了影响土壤中PAHs降解效率的主要因素(包括:PAHs的浓度水平、根系分泌物的种类、外源添加降解菌和土壤动物的数量和种类、菌属或土壤动物之间的种间竞争和部分环境因素等);同时通过综述近年来国内外强化生物联合修复PAHs污染土壤的技术原理、应用成果和存在的一些问题,指出了不同情况下制约PAHs强化降解进程的潜在限制因子(包括:表面活性剂和固定化微生物的添加量、不同表面活性剂的适度混合、载体材料的性质、固定化方式的选取、土壤养分和水分含量等);并强调在进行强化修复的过程中,要注重现场应用和安全性评价,为多环芳烃污染土壤的生物联合强化修复研究提供了理论依据和技术参考。     

增铵营养对小麦早期生长的促进效应

应用水培试验的方法,研究了小麦在不同形态氮营养下（ＮＨ＾＋４／ＮＯ＾－３分别为０／１００、５０／５０和１００／０）的生长特征。与单一形态氮营养相比,增铵营养在五叶期显著增加了小麦植株的株高、叶干重和总干重;在７叶期,显著增加了小麦株高、单株分蘖数、叶面积、叶干重、茎鞘干重、地上部干重和总干重。与单一ＮＯ＾－３营养相比,单一ＮＨ＾＋４营养显著降低单株分蘖数、叶面积、叶干重、茎鞘干重、根干重、地上部干     

Isolation and identification of oxamyl-degrading bacteria from UK agricultural soils

Bacteria capable of utilising oxamyl as the sole carbon source were isolated from seven different agricultural soils that had previously demonstrated enhanced oxamyl degradation in a soil incubation study. Partial sequencing and alignment of the 16S rRNA gene showed little diversity amongst isolates, with 26 of the 27 isolates demonstrating similarity to the genus Aminobacter. The most common species isolated was Aminobacter aminovorans, while a number of the isolates demonstrated an equal degree of similarity to the species Aminobacter niigataensis and Chelatobacter heintzii. One isolate was identified as Mesorhizobium sp. This is the first time that organisms involved in the degradation of oxamyl have been isolated and identified.     

表面增强拉曼光谱法快速检测牛奶中的三聚氰胺

基于表面增强拉曼光谱技术的便携式拉曼光谱仪运用于牛奶收购、运输过程中三聚氰胺的快速测定进行了研究。利用三聚氰胺位于708 cm-1~714cm-1的拉曼光谱特征峰及其强度,对三聚氰胺进行定性及半定量的快速测定。检测限为2.0 mg/L,常见含氮化合物尿素、亚硝酸钠等物质对本快速测定方法无干扰。对每个样品的检测时间从样品制备到结果显示一般只需10 min。     

禽霍乱强化苗研究——Ⅱ.与国外同类苗免疫比较

本试验将研制的禽霍乱强化苗与Intervet疫苗进行免疫比较试验。结果表明强化苗在免疫早期抗体产生时间优于Intervet疫苗。免疫1个月后,两种疫苗试管凝集抗体效价曲线无明显差异,免疫期均达6个月。两种疫苗1至6个月的攻毒保护率分别为94. 4％和86. 7％。两种疫苗免疫接种产蛋鸡后2周内,分别使免疫鸡的平均日产蛋量下降2.6％和6.5％、以上试验表明,本课题组研制的禽霍乱强化苗在免疫性方面已经达到或部分指标已超过国际同类先进产品的水平。     

UV-B辐射增强下水稻苗期硅营养性状的QTL定位及其与环境互作效应分析

以"Lemont"和"Dular"杂交建立的包含123个家系的水稻重组自交系(RILs)群体为材料,选用水稻根系硅吸收能力和叶片硅利用率为指标,进行水稻硅营养遗传性状QTL定位,并分析其与UV-B辐射增强的互作效应。结果表明,控制水稻叶片硅利用率的4个加性QTL分别在第2、3、10染色体上,而控制根系硅吸收能力的1个加性QTL位于第11染色体上。QTL与UV-B辐射互作分析发现2对控制根系硅吸收能力和3对控制叶片硅利用率的基因×环境上位性QTL,其中只有1对控制根系硅吸收能力的QTL效应值较大。说明水稻这两种硅营养性状中,根系硅吸收能力较叶片硅利用率受UV-B辐射影响大,在抗UV-B辐射育种中以叶片硅利用率为水稻硅营养遗传选择的指标具有较高效率。     

Western blot检测家兔动脉组织蛋白质表达条件的优化

蛋白质免疫印记技术是研究和分析蛋白质的重要手段,由于其步骤繁杂、影响因素众多,常出现背景噪音高、非特异条带多、拖尾等问题,严重影响后续蛋白质定量分析。为建立最佳的检测家兔动脉组织中蛋白质表达的蛋白质免疫印记技术实验条件,以家兔动脉组织血管细胞粘附分子-1为目标蛋白,从电泳条件、抗体浓度、抗体孵育时间、温度及方法、免疫显色方法等方面进行了改良,成功建立了快速、灵敏、特异的蛋白质免疫印记技术体系;并比较了3种常用的酶免疫显色技术:3,3’-二氨基联苯胺(3,3’-diaminobenzidine,DAB)显色、增强化学发光法(enhanced chemil luminescence,ECL)X光片曝光及ECL化学发光冷却电感耦合成像系统(cooled charged-coupled device,CCD)成像的敏感性。结果表明ECL化学发光法比DAB显色法敏感性高出2～10倍,其中CCD系统敏感性高于X光片4倍,且操作简便,是最理想的检测方法。