用于测定多环芳烃的酶联免疫吸附分析法的研究

将芘丁酸(1-pyrenebutyricacid,PBA)通过活性酯法与牛血清白蛋白(BSA)共价结合,以PBA-BSA结合物为免疫原制备抗血清,利用该抗血清建立了测定多环芳烃类物质的间接竞争酶联免疫吸附分析法(enzyme-linkedimmunosorbentassay,ELISA),并研究了10种多环芳烃与该抗血清的交叉反应。结果表明,该方法用于测定芘和芘丁酸的IC50值分别为0.132mg·L-1和0.253mg·L-1,检出限分别为0.1mg·L-1和0.01mg·L-1,该方法不受溶剂甲醇的影响,因此可以用于经过预富集的环境样品中多环芳烃类物质的测定。     

粒细胞系集落刺激因子对慢性肾功能衰竭患者影响的研究

为研究粒细胞系集落刺激因子对慢性肾功能衰竭的影响，方法；以酶标免疫测定法检测了３１例ＣＲＦ患者血清及尿－ＧＣＳＦ水平及４０例健康人血清及尿Ｇ－ＣＳＦ水平，并进行了相关分析。结果：ＣＲＦ患者血清及尿－ＧＣＳＦ水平分别是２４．１４±２．１ｐｇ／ｍｌ和３０．７２±１．８３ｐｇ／ｍｌ，高于健康对照组，Ｐ〈０．００１；ＣＲＦ血清Ｇ－ＣＳＦ与ＢＵＮ，Ｓｃｒ均无相关性，但血Ｇ－ＣＳＦ与尿Ｇ－ＣＳＦ水平呈正相关。     

转基因烟草植株的检测

对采用叶盘法以质粒PBLGC为介导转化烟草的3个品种。经Kan抗性筛选获得的119株转化的烟草再生植株分别以启动子CaMV35S、几丁质酶基因和β—1，3-葡聚糖酶基因的引物进行PCR检测，分别获得91、72、47株阳性植株。其中，同时具有几丁质酶基因和β-1，3-葡聚糖酶基因的植株有36株。对部分转化植株进行PCR—Southern杂交实验的结果表明，外源基因的转化频率与植物品种、外源基因片段的大小有关。又对4株转基因植株后代(T1)进行了PCR、PCR—Southern杂交，结果发现，几丁质酶基因和β-1，3-葡聚糖酶基因已经稳定地遗传给后代，但二者的遗传传递率不同，β—1，3-葡聚糖酶基因似乎比几丁质酶基因更易于传递。另外，对转化植株T0代几丁质酶活力检测结果表明，转基因植株中几丁质酶活力显著增强，含有几丁质酶基因和β-1，3-葡聚糖酶基因的植株内切几丁质酶活力最强。     

山羊产后乳中孕酮浓度的变化

应用放射免疫分析和竞争蛋白结合分析法测定了成都麻羊、莎能羊及其杂交一代母羊产后四月内的乳中孕酮浓度变化。供试动物在试验期间的孕酮浓度一般保持基础水平,约有87.2％(成都麻羊)、94.4％(莎能羊)和93.9％(杂交羊)的测值在10ng/ml以下。孕酮浓度升高发生1—5次,较行为发情次数为多。第一次孕酮浓度升高发生在产后26—67天(成都麻羊)、19—52天(莎能羊)和39—122天(杂交羊)期间。产后五天内初乳中的孕酮含量平均为每日2—4ng。     

A New Microbial Contact Assay for Marine Sediments (7 pp)

-  Dedicated to Prof. Dr. Ulrich Förstner on his 65th birthdayBackground, Aims and Scope   The number of microbiological contact tests for marine sediments is low, although microorganisms enable a rapid screening and monitoring of sediment quality and a high resolution of hazard assessment. As no single biotest can provide reliable answers concerning the potential hazard of environmental samples, a combination of bioassays needs to be applied to serve this purpose. In order to cover as many potential effects as possible, test organisms should have different sensitivities; assays should cover different exposure pathways, and measure the effect on various physiological functions. Methods   3 different Vibrio species (V. proteolyticus, V. natriegens, V. gazogenes) were tested for their suitability as test organisms in a contact assay on the basis of their activity, sensitivity and their spectrum of salinity tolerance. As a test endpoint, dehydrogenase activity over an incubation time of 2 hours (~ 3 generations) was chosen, quantified by resazurine reduction. The test was miniaturized to 96 well plates, including a dilution series, and quality criteria were established. The assay was then tested on natural sediments from a contaminated site in the Lübeck Bight.Results and Discussion   Vibrio proteolyticus proved to be the best suited test organism out of those tested for this bioassay. The miniaturized test system revealed a coefficient of variation of positive controls in 16 tests of 17.8 %. Its application to contaminated sediments from the Lübeck Bight showed a good differentiation of samples from different depths and zones, which reflected the general contamination pattern and capping activities in that area. Conclusion   The miniaturized test system that has been developed for V. proteolyticus is suited to assess toxic effects of brackish and marine sediments. Due to an increased number of replicates and an extensive sediment dilution series, the degree of certainty of hazard assessment is elevated.Recommendations and Outlook   The integration of this sediment contact assay as a complementary test in a microbiological test battery is recommended.     

Acetylene reduction,hydrogen evolution and nodule respiration in Phaseolus vulgaris

Summary In an experiment performed under greenhouse conditions, four cultivars of Phaseolus vulgaris L. (Venezuela-350; Aroana; Moruna; Carioca) were inoculated with three Rhizobium leguminosarum biovar phaseoli strains (C-05; C-40 = CIAT 255; C-89 = CIAT 55) and were fertilized with an N-free mineral nutrient solution. The plants were harvested 25, 40, and 55 days after emergence and the following paramenters were evaluated: Nitrogenase activity of nodulated roots, H₂ evolution by the nodules; relative efficiency of nitrogenase; respiration rates of nodulated roots and detached nodules; dry weight and total N of stems, leaves, pods, roots, and nodules. Generally the bean cultivar, Rhizobium strain, had an effect and there was an interaction effect with both symbiotic partners, on all parameters. On average, nodules represented 23% of total root respiration but the best symbiotic combinations showed lower ratios of C respired to N fixed. The maximum N-assimilation rate (between 40 and 55 days after emergence) of 11.93 mg N plant^–1 day^–1 occurred with the symbiotic combination of Carioca × C-05, while the poorest rate of 0.55 mg N plant^–1 day^–1 was recorded with Venezuela-350 × C-89. The best symbiotic combinations always showed the highest relative nitrogenase efficiency, but the differences in N₂-fixation rates cannot be explained solely in terms of conservation of energy by recycling of H₂. This requires further investigation.     

马立克氏病病毒MEQ蛋白对MDV增殖影响的研究

在马立克氏病病毒MDV致病机理的研究中，弄清致病基因meq与病毒增殖之间的关系及其分子机制是十分重要的基础，以重组反转录病毒（RCAS-meq)感染鸡胚成纤维细胞（CEF），使源于MDV强毒参考株（vMDV)GA株的meq基因表达于宿主细胞内，然后再用GA株感染这些细胞。通过利用MDV强毒株特异的抗pp38单克隆抗体所进行的“黑斑”试验以确定MDV的增殖水平，并与未接种RCAS-meq的CEF进行比较。研究结果发现，细胞内表达的meq基国产物可促进GA株于体外培养细胞中的感染与增殖（病毒斑数增多）。根据试验的结果，作者认为meq基因在感染细胞内的表达水平是MDV增殖以及进而能致病、致瘤的分子基础。     

Use of NaCN to increase the growth of N2-fixing bacteria in a model spermosphere mimicked by sucrose and amino acids leached by seeds

In order to study the establishment of a spermosphere, the C₂H₂ reduction activity of N₂-fixing bacteria isolated from river sand was examined in a simulated spermosphere in the river sand which contained sucrose, an amino acid mixture, and CN^- released from plant seeds. The sand incubated with 10^-10 to 10^-9 mol CN^- 30 g sand^-1 exhibited higher C₂H₂ reduction activity than that without CN^-. The change in the most probable number of N₂ fixers with increasing quantities of CN^- roughly corresponded to that in C₂H₂ reduction activity. However, the most probable number of non-N₂-fixing bacteria decreased except for CN^--tolerant ones. Both C₂H₂ reduction activity and proliferation of the N₂ fixers isolated on a modified Burk's medium were almost similar to those in the bacteria in the sand. In contrast, the proliferation of some nonfixers decreased with an increasing CN^- concentration. C₂H₂ reduction activity of N₂ fixers cultured in combination with non-fixers exhibited a clear peak at 10^-7 M CN^- as for C₂H₂ reduction activity in the sand. We therefore speculate that cyanide evolved from seeds during a pregermination period may suppress the growth of general bacteria, but may promote the proliferation of N₂ fixers, thus contributing to the establishment of a spermosphere.     

Comparative salinity tolerance of symbiotically dependent and nitrogen-fed pigeonpea (Cajanus cajan) and its wild relative Atylosia platycarpa

Summary Once symbiosis between the pigeonpea cultivar ICPL 227 and the Rhizobium sp. strain IC 3024 is established, it is efficient in fixing N₂ under saline conditions and can support growth comparable to N-fed plants in growth media with up to 6 dS m^-1 salinity. However, the early stages of establishment of the pigeonpea-IC 3024 symbiotic system have proved sensitive to salinity. The present study showed that the number of nodules was markedly reduced at 8 dS m^-1 salinity; however, nodule development and functioning were not affected by salinity in the pigeonpea-IC 3024 symbiosis. The symbiotic system of Atylosia platycarpa and Rhizobium sp. strain IC 3087 was established successfully even at 12 dS m^-1 and supported growth comparable to that of N-fed plants. P levels in leaves were increased under saline conditions in N-fed and N₂-fixing pigeonpea and A. platycarpa. There were no consistent differences in the leaf Na and chloride levels between N-fed and N₂-fixing plants of pigeonpea and A. platycarpa. The present study suggests that the rhizobial symbiosis may not be a necessary factor for initial screening of pigeonpea and related wild species for salinity tolerance.Submitted as JA No. 964 by the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT)