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摘要： 目的 研究表达型质粒载体 pMG36e 在大肠杆菌 JM109 和乳酸乳球菌 MG1363 两种宿主菌中的遗传稳定性并观察红霉素对其稳定性的影响。
方法 按经典质粒遗传稳定性测定方法，在有选择压力（加红霉素）和无选择压力的条件下，测定 pMG36e 质粒在大肠杆菌 JM109 和乳酸乳球菌 MG1363 中的遗传稳定率。
结果 pMG36e 质粒在大肠杆菌 JM109 中连续传至 120 代时，在有选择压力的条件下，质粒稳定率保持在 100% ；无选择压力的条件下为 96% ； pMG36e 质粒在乳酸乳球菌 MG1363 中连续传至 100 代时，在有选择压力和无选择压力的条件下，质粒稳定率均为 98% 。
结论 pMG36e 质粒在两种宿主菌中均具有较好的遗传稳定性。红霉素对 pMG36e 质粒的遗传稳定性无显著影响。
关键词： 质粒 遗传稳定性 红霉素
中图分类号： Q782 文献标识码： A
Study of the genetic stability of expression plasmid vector pMG36e in host bacteria
Wang Chuan ， Zhang Chao-wu ， Du Jiang
Department of Medical Technology, West china School of Public Health,Sichuan University, Chengdu 610041, China
Abstract: Objective To study the genetic stability of expression plasmid vector pMG36e in Escherichia coli JM109 and Lactococcus lactis MG1363/36e and observe the effect of erythomycin for its stability. Methods We used classical method to determine the genetic stable rates of pMG36e in E.coli JM109 and Lactococcus lactis MG1363/36e with or without erythomycin selective pressure. Results When E.coli JM109 were continuously incubated to 120 generations, its pMG36e genetic stable rates were 100% and 96% respectively with or without erythomycin selective pressure. When Lactococcus lactis MG1363/36e were continuously incubated to 100 generations, its pMG36e genetic stable rates were the same 98%, with or without erythomycin selective pressure. Conclusion pMG36e had good genetic stability in this two hosts. Erythomycin selective pressure had no significant effect for the genetic stability of pMG36e.
Key words: plasmid, genetic stability, erythomycin
锌对应激大鼠海马金属硫蛋白亚型表达的调控作用及机制研究
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陈伟强 程义勇 李树田 王冬兰 于志杰 洪燕
军事医学科学院卫生学环境医学研究所，天津 300050 |
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摘要：目的 观察不同锌摄入水平对应激大鼠海马脑区不同金属硫蛋白亚型表达的影响。
方法 将 Wistar 雄性大鼠随机分为 8 组：正常对照组、对喂组、缺锌组和补锌组及其相应的应激组，分别给予正常饲料、缺锌饲料和补锌饲料，以缺锌动物当日的饲料摄入量作为对喂动物次日的给料量。动物喂饲 1 周后开始束缚应激，持续 4 周。以血红蛋白镉饱和法测定脑组织金属硫蛋白含量，分离海马提取总 RNA ，以 RT-PCR 检测金属硫蛋白亚型 MT-1 mRNA 和 MT-3 mRNA 。 结果 缺锌动物出现血锌含量明显降低，脑组织金属硫蛋白含量和海马金属硫蛋白 mRNA 的表达均出现降低，但其表达在缺锌应激组动物仍有明显升高；而补锌动物金属硫蛋白的表达有所增加，补锌应激组动物的表达增加更加明显。缺锌和缺锌应激组动物的血浆皮质醇、 IL-1 、 IL-6 和 NO 水平也较其它组显著升高。 结论 缺锌可降低动物脑和海马组织中金属硫蛋白的表达，但缺锌动物在接受应激刺激后，金属硫蛋白的表达仍可明显增加；而补锌可增加金属硫蛋白的表达，补锌应激使脑组织中金属硫蛋白的表达升高更为显著；应激对动物的损伤作用与其锌营养状况有关，缺锌可降低机体对应激的抵抗能力。
关键词： 束缚应激 金属硫蛋白 锌 皮质醇
中图分类号： R151.3 Q513 Q581 文献标识码：
Effects of zinc on the expression of metallothionein isoforms in hippocampus of stressed rats
Chen Wei-qiang, Cheng Yi-yong, Li Shu-tian, Wang Dong-lan, et al.
Institute of Health and Environmental Medicine, Academy of Military Medical Sciences, Tianjin 300050, China
Abstract: Objective This study was conducted to evaluate the effects of different doses of zinc on the expression of metallothionein isoforms in hippocampus of stressed rats. Methods The animal model of psychological stress was developed by restraint stress for four weeks. Wistar rats were randomly assigned to eight groups as follows: control group, zinc deficiency group, pair-feed group, zinc complementarity group and their corresponding stressed groups. Results In zinc deficiency group, plasm zinc content was decreased, while in zinc complementarity group it's slightly increased. On the one hand, the expressions of metallothionein in brain and MT-1 mRNA , MT-3 mRNA in hippocampus were downregulated in zinc deficiency group, however, their expressions were evidently enhanced in stressed zinc deficiency group. On the other hand, inductions of metallothionein and it's mRNAs in zinc complementarity group were increased, furthermore, stressed zinc complementarity group has more significantly yield of metallothionein and it's mRNAs. In addition, the levels of plasma cortisol, IL-6, IL-1 and NO were increased clearly in zinc deficiency group and stressed zinc deficiency group. Conclusion Our results suggested that zinc deficiency may decrease while zinc complementarety increase the expressions of metallothionein in brain and MT-1 mRNA, MT-3 mRNA in hippocampus, moreover, stress can increased their expressions dramatically. The impairment of stress on body may be involved with the nutrition status of zinc, and zinc deficiency can lower the body's resistibility to stress. Key words: restraint stress, metallothioneins, zinc, cortisol
基金项目： 国家自然科学基金资助项目（ No. 30100149 ）
作者简介： 陈伟强，男，博士研究生
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BALB/c 小鼠食物过敏动物模型的实验研究
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吕相征 刘秀梅 郭云昌 杨晓光
中国疾病预防控制中心营养与食品安全所，北京 100050 |
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摘要：目的 BALB/c 小鼠作为食物过敏动物模型的可行性也一直存在争议，本研究探讨 BALB/c 小鼠作为食物过敏动物模型的可行性。
方法 对相应试验组动物分别腹腔注射 0.25ml 20mg/ml 卵清蛋白（ OVA ）、牛血清白蛋白（ BSA ）、大豆胰蛋白酶抑制剂（ TI ）和马铃薯酸性磷酸酶（ PAP ）共两次，间隔为一周。检测血浆中的组胺水平和血清中特异 IgE 抗体含量，同时进行 皮肤过敏反应实验（ PCA ）。
结果 OVA 、 BSA 、 TI 及 PAP 组 32 倍稀释血清中均可检测到特异 IgE 抗体； 血浆中组胺水平较对照组显著升高。 常见致敏食物蛋白质 OVA 和 TI 、 不常见致敏食物蛋白质 BSA 和 无致敏史食物蛋白质 PAP 均可致使 BALB/c 小鼠产生的过敏反应。
结论 BALB/c 小鼠不适合作为食物过敏动物模型，本研究为解决 BALB/c 小鼠是否可以作为食物过敏动物模型的争议提供了理论依据。
关键词：食物过敏 动物模型 BALB/c 小鼠
中图分类号： R155.3 文献标识码： A
Assessment of the BALB/c mice as a suitable animal model for the investigation of food allergy
Lu Xiang-zheng, Liu Xiu-mei, Guo Yun-chang, Yang Xiao-guang
Institute of Nutrition and Food Safety, Chinese Center for Disease Control and Prevention, Beijing 100050, China
Abstract: Objective This study was to develop a suitable model for the investigation for food allergy. Methods BALB/c mice were dosed by intraperitoneally with Ovalbumin, Beef serum albumin , Trypsin inhibitor or Potato acid phosphatase respectively (0.25ml 20mg/ml) on day 0 and again on day 7. Control group was dosed with PBS. Sera form individual animals were analysed for specific IgE and Passive cutaneous anaphylaxis tests . Additionally, the level of histamine in plasma were detected. Results The high titres of specific IgE (1:32) could be provoked in test groups compared with control group. In addition, the level of histamine in plasma of test groups was higher than that in the control group. But there was no statistical significance between group food allergen and group Potato acid phosphatase. Conclusion Although allergic action of BALB/c mice could be provoked, the situation of the allergic action of BALB/c mice to the proteins was very different with the human being. T he BALB/c mice could not be a suitable model for the investigation for food allergy.
Key words: food allergy, animal model, BALB/c mice
基金项目：国家高技术研究发展计划 “863” （ No.2001AA212291 及 2002AA212041 ）； 国家重点基础研究发展规划 “973” （ No. 001CB109007 ）
作者简介：吕相征，男，博士研究生
1 通讯作者：刘秀梅，女，研究员，博士生导师 |
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