四川盆地部分地区土壤中苏云金芽胞杆菌分离与cry基因鉴定*

［目的］ 对四川盆地土壤中Bt资源进行研究,了解其分布特点,为我国苏云金芽胞杆菌的储备奠定基础。［方法］ 从四川盆地5个地区采集土样,分离苏云金芽胞杆菌野生菌株。利用PCR RFLP及SDS PAGE方法对Bt分离株进行基因型鉴定和蛋白分析,并对其室内杀虫活性进行初步测定。［结果］ 从207份土样中获得26株苏云金芽胞杆菌野生菌株,出菌率为12.56%。油镜观察可看到球形、方形、菱形及不规则形的伴胞晶体。在21株Bt分离株中检测到cry1、cry1I、cry2、cry9四类基因,且多数菌株都是同时含有多个基因类型,有5株Bt分离株未发现已知基因;SDS-PAGE显示有9株菌株只表达了130 ku的蛋白, 2株只表达了124 ku的蛋白,2株只表达了45 ku的蛋白,6株同时表达了130 ku和60 ku的蛋白, 4株同时表达了124 ku和60 ku的蛋白, 2株同时表达了135 ku和60 ku的蛋白, 1株同时表达了130、90 ku及75 ku的蛋白。毒力测定结果表明：9株菌株对小菜蛾具有高毒力,2株对大猿叶虫有一定的杀虫活性。［结论］四川盆地土壤中Bt资源多样性丰富,其中有2株有一定的研究前景。     

用6个小麦─黑麦衍生系筛选与黑麦抗条锈病基因连锁的RAPD标记

用ＲＡＰＤ分析６个艺性状不同的小麦－麦抗条锈病衍生系材料，建立与黑麦抗条锈病基因连锁的分子标记。结果表明，所用６个随机引物中，４个引物在６个衍生系中扩增出６个黑麦特有的产物，其大小约１９７－９８０ｂｐ，分别被标记为Ｊ１７，Ｊ１８ａ，Ｊ１８ｂ，Ｊ１１ａ，Ｊ１１ｂ和Ｄ５。     

东北赤霉病菌对杀菌剂敏感性及其应用的研究

采用室内生物测定法对东北小麦赤霉病菌 11个菌株对杀菌剂的敏感性进行了测定。结果发现 :田间菌株对多菌灵的耐药性普遍增强 ,达 4倍以上 ;禾谷镰孢菌的子囊孢子和分生孢子对杀菌剂抵抗能力强于菌丝体。毒力测定和田间药效试验表明 :有效地防治赤霉病必须选择对子囊孢子和分生孢子毒力强的杀菌剂 ,多·代混剂和克百菌是目前防治赤霉病较好的杀菌剂     

庆大霉素在猪肉和鸡肉组织中残留的微生物学检测方法研究

以表皮葡萄球菌 2 6 0 6 9型 (Staphylococcusepidermidis,ATCC12 2 2 8)为测试菌 ,用微生物学杯碟法定量测定庆大霉素在猪肉和鸡肉组织中的残留。庆大霉素在磷酸盐缓冲液、鸡和猪的肌肉组织中的最低检测限分别为 0 .0 2 5 μg/ml、0 .0 5 μg/g和 0 .0 5 μg/ g ,在磷酸盐缓冲液中标准曲线的线性范围为 2 .5× 10-2 ～ 0 .8μg/ml。庆大霉素浓度为 0 .0 5、0 .10、0 .2 0 μg/g时 ,鸡肉组织中的回收率分别为 (85 .8± 4 .5 ) %、(90 .1± 5 .9) %和 (88.8± 5 .3) % ,猪肉组织中的回收率分别为 (83.5± 7.1) %、(85 .2± 5 .4 ) %和 (86 .9± 6 .7) % ,日内和日间变异系数均小于 10 %。结果表明 ,本法快速、灵敏、简便 ,适用于庆大霉素在猪和鸡肌肉中残留的定量检测     

鸭病毒性肝炎间接血凝诊断抗原的制备

【研究目的】建立一种便于检测鸭病毒性肝炎抗体的方法。【研究方法】将纯化的鸭病毒性肝炎I型病毒(DHV-I)致敏双醛化红细胞,制备检测DHV抗体的间接血凝诊断抗原。【研究结果】使用该抗原对9种常见的禽传染病阳性血清、15只随机抽样的非免疫鸭血清进行检测,抗体均为阴性;检测被鸭病毒性肝炎I型病毒阻断后的阳性血清,抗体为阴性;用不同批次的诊断抗原检测同一血清样品结果显示一致;敏感性是琼脂扩散试验的32～64倍;对15只随机抽样的免疫鸭进行检测,阳性率达93%。【结论】该方法敏感性较高、特异性强、重复性好,可用于疫苗免疫后抗体水平的检测及鸭病毒性肝炎的流行病学调查。     

MTT比色法检测孕牛淋巴细胞转化的效果

选择３０头妊娠奶牛，根据妊娠阶段不同分为妊娠前期（小于１００ｄ）、妊娠中期（１００—２００ｄ）和妊娠后期（大于２００ｄ）３组，应用ＭＴＴ比色法测定妊娠母牛的外周血淋巴细胞转化能力．结果是妊娠母牛淋巴刺激指数明显低于未妊娠牛（Ｐ＜０．０５），不同妊娠天数之间差异不显著（Ｐ＞０．０５）．这就说明妊娠时母体的细胞免疫功能是下降的     

一种新的快速鉴定蛋白与靶DNA结合位点的方法

DREB转录因子在植物逆境胁迫响应中起非常重要的作用, 对植物的生长发育起重要的调控作用。传统的DNA酶I足迹法应用同位素标记DNA, 采用序列胶分离DNase I酶切片段, 操作较复杂, 分辨率较低, 不适用于高通量的样品检测。为阐明植物体内DREB转录因子的调控机制, 本研究利用改进的DNA酶I足迹法(DNase I Foot-printing)结合凝胶阻滞法(electrophoretic mobility shift assay, EMSA), 选用荧光色素代替同位素标记, 毛细管电泳技术代替序列胶检测DNase I酶切片段, 判定GmMYB1蛋白与GmDREB3启动子DNA结合的区域。采用限制性内切酶酶切GmDREB3启动子DNA验证以上结果。同时, 在判定的GmMYB1结合区域的基础上, 选择可能的DNA结合元件与GmMYB1进行EMSA试验, 证明GmMYB1可以与相应元件结合。该方法比传统的DNA酶I足迹法快速、简便、准确并可靠, 作为一种高通量的鉴定方法可用于大规模鉴定蛋白质的DNA结合位点。     

Taking stock of the assisted migration debate

Assisted migration was proposed several decades ago as a means of addressing the impacts of climate change on species populations. While its risks and benefits have been debated, and suggestions for planning and management given, there is little consensus within the academic literature over whether to adopt it as a policy. We evaluated the main features of the assisted migration literature including the study methods, taxonomic groups, geographic regions and disciplines involved. We further assessed the debate about the use of assisted migration, the main barriers to consensus, and the range of recommendations put forth in the literature for policy, planning or implementation. Commentaries and secondary literature reviews were as prevalent as first-hand scientific research and attention focussed on a global rather than regional level. There was little evidence of knowledge transfer outside of the natural sciences, despite the obvious policy relevance. Scholarly debate on this topic has intensified during the last 3 years. We present a conceptual framework for evaluating arguments in the debate, distinguishing among the direct risks and benefits to species, ecosystems and society on the one hand, and other arguments regarding scientific justification, evidence-base and feasibility on the other. We also identify recommendations with potential to advance the debate, including careful evaluation of risks, benefits and trade-offs, involvement of relevant stakeholders and consideration of the complementarity among assisted migration and less risk-tolerant strategies. We conclude, however, that none of these will solve the fundamental, often values-based, challenges in the debate. Solutions are likely to be complex, context-dependent and multi-faceted, emerging from further research, discussion and experience.     

Tree roots in canopy soils of old European beech trees—An ecological reassessment of a forgotten phenomenon

The formation of adventitious roots in humus accumulations in tree canopies is widely acknowledged from tropical and temperate rainforests, while the occurrence of those canopy roots in temperate tree species under mesic climates has been largely disregarded for ca. 100 years. Moreover, almost nothing is yet known of the ecological growth conditions or the structure or morphology of such canopy root systems. This study reports on the occurrence of tree fine roots in crown humus pockets of old European beech (Fagus sylvatica L.) trees. The aim was to compare these canopy roots with the fine roots in the terrestrial organic layer soil in terms of fine root biomass density, root morphological traits, ectomycorrhizal colonisation and chemical composition of the root tissue, and to relate these root traits to the chemical properties of the respective soils. Fine root biomass density in crown humus pockets was ca. 7 times higher than in the terrestrial organic layer, even though soil chemical properties of both rooting media were similar. Fine roots in the canopy differed from terrestrial fine roots by lower specific root tip abundance, specific root length, and specific root surface area, all of which points to a longer lifespan of the fine roots in the canopy. Moreover, canopy roots revealed a lower percentage of root tips colonised by ectomycorrhizal fungi than terrestrial roots (87% vs. 93%). Chemical composition of the root tissue in canopy and terrestrial soils was similar for most elements, but canopy roots showed lower P, Fe, and Al concentrations and a higher N/P ratio than terrestrial roots. Root P concentrations of both canopy and terrestrial fine roots were closely related to soil P concentration, but not to soil C/P or N/P ratios. On the other hand, tissue N of canopy roots, but not of terrestrial roots, revealed a clear dependence on soil N and C/N values, suggesting a more limited N availability in the canopy soil compared to the terrestrial organic layer. However, the overall small differences in soil chemical properties between canopy and terrestrial organic layer soil cannot explain the markedly higher volumetric root density in the crown humus and the differences in ecomorphological traits between canopy and terrestrial soil. Instead, it is speculated that these differences are more likely a result of temporarily high water availability in crown humus pockets due to high water flow along the surface of branches to the central crown parts of the beech trees.     

酶联免疫吸附技术在食品安全检测中的应用研究进展

介绍了酶联免疫吸附实验原理,阐述了该技术在食品安全检测中的应用研究进展.讨论了该技术的发展趋势及其应用前景.