FD耐热逆转录酶的部分酶学性质研究

ＦＤ耐热逆转录酶（ＦＤ－ＴＲＴ）来自一株栖热杆菌菌株．通过ＲＴ－ＰＣＲ方法,论文对ＦＤ－ＴＲＴ的部分酶学性质进行了研究．ＦＤ耐热逆转录酶能耐受９５℃的高温,最适反应温度在６５～７５℃左右,这时ＲＮＡ的高级结构能解开,可以提高逆转录反应的效率;同时引物和ＲＮＡ模板识别的专一性强,可大大提高逆转录的特异性．实验表明ＦＤ－ＴＲＴ逆转录反应的最适条件为：２５ｍｍｏｌ／ＬＴｒｉｓ－ＨＣｌ（ｐＨ８．８,１５ｍｍｏｌ／Ｌ（ＮＨ４）２ＳＯ４,１００μｇ／ｍｌ明胶,５００μｍｏｌ／ＬｄＮＴＰｓ,２５ｐｍｏｌ逆转录引物,１ｍｍｏｌ／ＬＭｎＣｌ２,２ＵＦＤ耐热逆转录酶,反应在６５～７０℃下进行．在上述条件下,用ＲＴ－ＰＣＲ可检出少于５ｐｇ外周血总ＲＮＡ中特异的α珠蛋白ｍＲＮＡ．     

Oxidative folding of reduced and denatured huwentoxin-I

Huwentoxin-I, a neurotoxic peptide with 33 ammo acid residues and three disulfide bonds, was used to investigate the pathway of reduction/denaturation and of oxidative folding in small proteins with multiple disulfide bonds. Titration of thiol groups, reversed-phase HPLC, 1D NMR spectroscopy, and biological activity assays were used to monitor the extent of reduction/denaturation and renaturation of the toxin. The reduction and denaturation of huwentoxin-I resulted in a 100% loss of bioactivity as measured in a mouse phrenic nerve-diaphragm preparation. About 90% of full biological activity could be restored under optimized conditions of oxidative refolding of the reduced peptide. Several reaction conditions employing air oxidation, oxidized and reduced glutathione (GSSG and GSH), and cystine/cysteine were investigated in order to find optimal conditions for renaturation of huwentoxin-I. The best renaturation yield was achieved in 0.1 mM GSSG and 1 mM GSH at pH 8.5 and 4°C over 24 hr. High concentrations of glutathione and high temperatures reduced renaturation yields. Oxidative refolding of huwentoxin-I in air requires about 6 days for maximal yields and is inhibited by EDTA.     

树鼩室旁核血管加压素免疫阳性神经元的电镜观察

用免疫组化 PAP 技术,对树鼩(Tupaia Belangeri)室旁核血管加压素(VP)免疫阳性神经元进行电镜观察。发现室旁核 VP 阳性神经元核固体内的 VP 阳性反应物主要与高尔基复合体、神经分泌颗粒有关。但在粗面内质网未见 VP 阳性反应物,这与前人对大鼠的研究报告不同。     

氯胺酮对培养神经元无氧与再灌损伤保护作用机理的研究

采用１６－１８ｄ胎龄的大鼠皮层细胞分离培养,分别观察无氧再灌和谷氨酸对皮层神经元的影响以及氯胺酮的保护作用。结果如下：培养１２ｄ的细胞先置于缺氧环境中５ｈ,再灌０－２４ｈ后,随着无氧再灌时间延长,ＬＤＨ漏出增加。外源性谷氨酸也引起ＬＤＨ的漏出增加。无氧再灌和谷氨酸处理前,于培养液中加入氯胺酮,则ＬＤＨ漏出量均明显低于对照组。结果表明,无氧和再灌及过量谷氨酸均造成皮层神经元严重损伤,氯胺酮对上述损伤皆有明显的保护作用。以上结果说明谷氨酸兴奋毒性与ＮＭＤＡ受体在缺血性脑损伤过程起着至关重要的作用。     

衰老细胞转录因子AP_1/CREB结合活性对EGF的可诱导性下降

转录因子与ＤＮＡ的结合是基因转录的关键环节．通过迁移位移法分析了转录因子ＡＰ１、ｃＡＭＰ反应元件结合蛋白（ＣＲＥＢ）、糖皮质激素反应元件（ＧＲＥ）结合蛋白在衰老细胞中的结合活性．结果表明,ＡＰ１与ＣＲＥＢ的结合活性在衰老细胞中对表皮生长因子（ＥＧＦ）的反应性低于年轻细胞;而ＧＲＥ结合蛋白的结合活性在衰老细胞中对ＥＧＦ的反应性无明显变化．这提示ＥＧＦ不能有效刺激衰老细胞增殖可能与其转录因子结合活性的改变有关     

The strategic role of ecological research in the design of an environmentally comprehensive plan for a new economic-development area–Meizhou Bay,China

The Government of China is planning a new economic-development area, located at Meizhou Bay on the Chinese mainland, opposite the island of Taiwan. Aspects of this development plant will be subject to an assessment of the potential environmental effects. Especially important considerations are changes in land use associated with urbanization and industrial developments, and any activities that could degrade air and water quality, with potential risks for human health, aquaculture, agriculture, and wildlife. During 1988 to 1990, we conducted studies related to meteorology, environmental geology and engineering, physical oceanography, and marine chemistry and biology.To protect culturally-important orchards of fruit trees (including litchi, orange, and tangerine) from air pollution, and aquaculture facilities for prawn and oyster from oil pollution, these toxic stressors were given priority in our eco-toxicological research, and in the planning of allowable waste discharges. To protect Meizhou Bay from eutrophication, and nutrient-loading eco-dynamic models were developed, to allow simulation of ecological changes potentially associated with nutrient-laden discharges. The results of our ecological research will play a strategic role in reconciling conflicts between economic development and environmental degradation, over both the short- and the long-term.     

水稻籼粳杂种F2群体中RFLP标记的异常分离及其染色体分布

利用水稻 Oryza sativa L.,2 n=2 4 1 2对染色体上的 5 4个 DNA限制性片段长度多态性 RFL P 标记 ,研究了它们在籼粳杂种 窄叶青 8号 / 京系 1 7 F2 群体中的分离 .结果表明 ,2 5 .9%的 RFLP标记的分离显著或极显著地偏离了预期的孟德尔比例 1∶ 2∶ 1 而表现为异常分离 .F2 群体中 3类 RFL P基因型中 窄叶青 8号 类型明显偏多 ,其基因频率为5 2 .1 % .同时还发现了 3个异常分离的染色体热点 ,即第 3染色体上的 RG2 2 7- RG369,第 7染色体上的 RG678- RG5 1 1 - RG5 2 8,以及第 1 2染色体上的 RG4 63- RG32 3,它们可能与导致异常分离的配子体基因座位有关 .     

Total synthesis and stereochemical reassignment of tasiamide B

The first total synthesis of tasiamide B, an octapeptide bearing 4‐amino‐3‐hydroxy‐5‐phenylpentanoic acid unit isolated from the marine cyanobacteria Symploca sp. is described. A simple and efficient way was found to avoid the pyroglutamylation of N^α‐Me‐Gln and led to a reassignment of the N^α‐Me‐L ‐Phe of tasiamide B to be N^α‐Me‐D ‐Phe, which was also supported by 1D and 2D NMR. Copyright © 2010 European Peptide Society and John Wiley & Sons, Ltd.     

Cell Apoptosis Induced by Oligosaccharide in Suspension Cultures of Taxus chinenesis

Taxol production of Taxus chinensis（Pilger） Rehd. var.mairei (Lemeeet Lévl.) Cheng et L. K. Fu induced by oligosaccharide from Fusarium oxysporum f.vasinfectum (Atkinson) Snyder et Hansen was studied in suspension cultures, and it was found that oligosaccharide triggered cell apoptosis. Under transmission electron microscope the following morphological changes were observed: cell shrinkage, condensation of cytoplasm, nuclear fragmentation, and the increase of high electron density bodies in vacuole in great quantity. In oligosaccharide treated cells, agarose gel electrophoresis revealed that DNA was digested into oligonucleosomal fragments that were times of 200 bp appearing as DNA ladders. Control cells were in normal physiological state, they were intact, abundant in organelle and with integral nucleus DNA, and the rate of taxol biosynthesis in these cells was very low. After the oligosaccharide to the culture system, the defense system of cells was elicited and the secondary metabolism was strengthened, i.e. phenolics were accumulated in the medium, the activity of polyphenol oxidase (PPO) was increased quickly and secondary wall of cells was thickened. The activity of L phenylalanine ammonia lyase (PAL), the critical enzyme of the phenylpropanoid pathway, was increased promptly 1 h after elicitation. The rate of taxol production was improved sharply and the maximal taxol concentration at 72 h was six times that of control. Appearance of cell apoptosis was accompanied with the highest concentration of taxol in suspension cultures.