家蚕微孢子虫(Nosema bombycis)侵染家蚕丝腺组织后的免疫胶体金标记观察

为了探讨家蚕微孢子虫(Nosema bombycis)功能基因组研究方法和手段,利用免疫胶体金标记电镜技术,对被感染的家蚕丝腺组织中家蚕微孢子虫的蛋白质分泌状况进行了观察。结果显示,有大量的胶体金颗粒存在于家蚕微孢子虫寄生位点的宿主组织内,说明了家蚕微孢子虫寄生位点的宿主组织内存在大量的孢子蛋白质,证实了家蚕微孢子虫在寄生过程中将许多孢子蛋白质分泌到宿主体内。初步探讨了家蚕微孢子虫与宿主家蚕之间的互作关系。     

A菌根真菌外生菌丝对难溶性无机磷酸盐的活化及利用Ⅰ.~(32)P间接标记法

采用三室栽培装置培养三叶草 ,接种VA菌根真菌Glomusmosseae。将根系与VA菌根真菌外生菌丝隔开 ,在菌丝室施用 5种磷酸盐和32 P间接标记磷肥 ,研究外生菌丝对难溶性磷酸盐的活化利用能力。结果表明 ,外生菌丝可以活化吸收磷酸二钙、磷酸八钙、磷酸铝和磷酸铁 ,无法活化利用磷酸十钙 ;各种磷酸盐被活化吸收的量及其对三叶草磷营养的贡献率的大小顺序是磷酸二钙 >磷酸八钙、磷酸铝 >磷酸铁     

免疫胶体金标记技术及其在植物保护上的应用前景

综述了胶体金制备、质量鉴定方法 ,胶体金探针的制备、纯化方法 ,以膜为固相载体的免疫胶体金快速试验即免疫层析和免疫渗滤试验技术 ,以及免疫胶体金标记技术在植物保护研究领域中的应用前景。     

O型口蹄疫单克隆抗体6H4株金标试纸条的制备

以制备的O型口蹄疫单克隆抗体为基础,结合免疫金技术,采用柠檬酸三钠还原法制备胶体金颗粒,对6H4单克隆抗体进行标记,制备了该单克隆抗体的金标试纸条.研究结果表明,6H4单克隆抗体在pH 8.64下的稳定点为12 mg/L,可制备成金标记抗体及其反应膜.     

Reduction of bacterial growth by a vesicular-arbuscular mycorrhizal fungus in the rhizosphere of cucumber (Cucumis sativus L.)

Summary Cucumber was grown in a partially sterilized sand-soil mixture with the vesicular-arbuscular mycorrhizal (VAM) fungus Glomus fasciculatum or left uninoculated. Fresh soil extract was places in polyvinyl chloride tubes without propagules of mycorrhizal fungi. Root tips and root segments with adhering soil, bulk soil, and soil from unplanted tubes were sampled after 4 weeks. Samples were labelled with [³H]-thymidine and bacteria in different size classes were measured after staining by acridine orange. The presence of VAM decreased the rate of bacterial DNA synthesis, decreased the bacterial biomass, and changed the spatial pattern of bacterial growth compared to non-mycorrhizal cucumbers. The [³H]-thymidine incorporation was significantly higher on root tips in the top of tubes, and on root segments and bulk soil in the center of tubes on non-mycorrhizal plants compared to mycorrhizal plants. At the bottom of the tubes, the [³H]-thymidine incorporation was significantly higher on root tips of mycorrhizal plants. Correspondingly, the bacterial biovolumes of rods with dimension 0.28–0.40×1.1–1.6 m, from the bulk soil in the center of tubes and from root segments in the center and top of tubes, and of cocci with a diameter of 0.55–0.78 m in the bulk soil in the center of tubes, were significantly reduced by VAM fungi. The extremely high bacterial biomass (1–7 mg C g^-1 dry weight soil) was significant reduced by mycorrhizal colonization on root segments and in bulk soil. The incorporation of [³H]-thymidine was around one order of magnitude lower compared to other rhizosphere measurements, probably because pseudomonads that did not incorporate [³H]-thymidine dominated the bacterial population. The VAM probably decreased the amount of plant root-derived organic matter available for bacterial growth, and increased bacterial spatial variability by competition. Thus VAM plants seem to be better adapted to compete with the saprophytic soil microflora for common nutrients, e.g., N and P, compared to non-mycorrhizal plants.     

Identification of groups of metabolically-active rhizosphere microorganisms by stable isotope probing of PLFAs

We combined microbial community phospholipid fatty acid (PLFA) analyses with an in situ stable isotope ¹³CO₂ labelling approach to identify microbial groups actively involved in assimilation of root-derived C in limed grassland soils. We hypothesized that the application of lime would stimulate more rapid ¹³C assimilation and turnover in microbial PLFAs. Four and 8 d after label application, 18:1ω9, 18:2ω6,9 (fungal biomarkers) and 16:1ω7, 18:1ω7, 19:0cy (Gram-negative bacterial biomarkers) showed the most ¹³C enrichment and rapid turnover rates. This suggests that these microorganisms were assimilating recently-photosynthesized root C inputs to soils. Contrary to our hypothesis, liming did not affect assimilation or turnover rates of ¹³C-labelled C. ¹³C stable isotope pulse-labelling technique paired with analyses of PLFA microbial biomarkers shows promise for in situ investigations of microbial function in soils.     

应用免疫胶体金标记技术对狂犬病病毒形态发生学的抗原定位研究

利用包埋后免疫胶体金标记技术，通过透射电子显微镜，对感染ＢＨＫ２１细胞的鹿狂犬病病毒进行了形态发生的抗原定位。结果：感染细胞的细胞质内有５种包涵体，其中４种被免疫胶体金特异性标记，这些病毒抗原是多成分的，另一种未被免疫胶体金标记的包涵体可能是病毒核酸；感染细胞的细胞质内大量堆积的病毒前体物质包涵体，其中可能有病毒装配后多余的成分，表明病毒各组分并不是按比例需要而合成的。     

Determination of iron absorption by rat bioassay. Evaluation of methods of dosing59Fe on radioiron absorption from plant diets

We studied the potential of an animal model to predict nonheme iron absorption in humans and tested a feasible and easy technique of dosing⁵⁹Fe to evaluate bioavailability of dietary nonheme iron. Plant diets containing about 20 ppm or 75 ppm iron were the nonheme iron sources with ferrous sulfate (75 ppm) as a reference. Radioiron was administered by (a) gavaging in water, 1 h after a meal; (b) mixing with the meal; and (c) making a slurry with the meal and gavaging. No significant differences were found (P0.05) in⁵⁹Fe absorption among the three methods of administering radioiron. Absorption of⁵⁹Fe was similar to apparent iron absorption for all diets tested, whether the animals consumed the same diet as that of the test meal or a different diet. A high correlation (r=0.88) obtained between the apparent iron absorption and⁵⁹Fe iron absorption for different dosing techniques, indicates that extrinsic iron tag administered by any of these methods is valid to measure nonheme iron absorption. Apparent iron absorption values determined by rats fed 20 ppm or 75 ppm dietary iron from plant sources were similar to reported values for humans. It is concluded that the normal adult rat is an appropriate model to study iron bioavailability of human foods when iron status, maturity, iron intake relative to requirement, and method of measurement are similar to the human situation.     

Fair trade fish: consumer support for broader seafood sustainability

Sustainable seafood initiatives began with efforts to promote and certify seafood sourced from well‐managed stocks caught with a reduced impact on the marine environment. More recently, social equity in fisheries has been the subject of increased concern with suggestions that seafood cannot be certified as sustainable if its production results in social harm, such as unfair wages or the use of forced or child labour. Together with local seafood, which has been promoted as an eco‐friendly and socially conscious alternative to globally sourced seafood, these initiatives signal a growing interest in fisheries as a social–ecological system. However, this increasingly complex landscape of environmental sustainability and social justice may be difficult for the public and seafood consumers to navigate. Here, we investigate consumer understanding of and responsiveness to a range of seafood sustainability initiatives by testing preferences and willingness to pay (WTP) for seafood across the three types of sustainability: ecological sustainability, local origin and social sustainability. More than half of respondents demonstrated good understandings of both ecological sustainability and social sustainability with respect to seafood, and respondents were willing to pay more for all three types of sustainability. However, WTP for social sustainability benefits was the lowest, and consumers perceived a high degree of overlap of these benefits with those from locally sourced seafood. These results indicate that seafood certification taking a system‐wide approach has potential to succeed, but that it will need to emerge in concert with the increased public education about social problems associated with globalized fisheries.