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931.
932.
尖吻蝮蛇蛇毒出血毒素的纯化与部分性质 总被引:1,自引:0,他引:1
目的 被尖吻蝮蛇 ( Dienagkistrodon acutus) 咬伤会引起严重的出血, 对蛇毒出血毒素的研究有利于治疗蛇伤出血药物筛选。 方法 采用 Sephadex G75, D E A E Sephadex A50, Sephadex G200 和两次 P B E 聚焦层析纯化。 S D S P A G E 电泳和等电聚焦电泳测定纯化样品的纯度和等电点。氨基酸组成用自动氨基酸分析仪测定。以小鼠背部皮下注射部位出血斑的面积来确定最小出血剂量和常规的方法测定酶活性。结果 从尖吻蝮蛇毒中纯化到一个相对分子量为56 000 的出血毒素 ( Da H T3), 经氨基酸组成测定计算,它由 487 个氨基酸残基组成。此成分在 S D S P A G E上显示出一条均一的蛋白染色带, 其p I为550。该出血成分的最小出血剂量是 26μg, 具有蛋白水解酶活力, 其活力为 368, 但没有精氨酯酶和磷脂酶 A2 活力。当加入 E D T A 螯合剂去除金属离子后, 它们的出血活力和蛋白水解酶活力均丧失。 结论 这是从大陆尖吻蝮蛇毒中获得的一个新的出血金属蛋白酶 ( Da H T3)。 相似文献
933.
准噶尔小胸鳖甲抗冻蛋白MPAFP5毕赤酵母表达产物的理化性质 总被引:2,自引:0,他引:2
研究准噶尔小胸鳖甲Microdera punctipennis dzhungarica Kasz抗冻蛋白MPAFP5真核表达产物的功能及理化性质。首先用硫酸铵浓度梯度沉淀初步纯化酵母真核表达产物,然后通过细菌低温保护实验检测抗冻蛋白MPAFP5低温保护功能,同时探讨抗冻蛋白MPAFP5在酸碱环境和100℃时的稳定性,并通过等电聚焦凝胶电泳检测其等电点。研究表明MPAFP5真核表达产物在低温下能够提高细菌的存活率,能够耐受高温和一定程度的强酸强碱,其等电点约为5.8左右。准噶尔小胸鳖甲抗冻蛋白MPAFP5真核表达产物与赤翅甲抗冻蛋白(DAFP)的比较表明拟步甲类昆虫抗冻蛋白具有相似的理化性质。 相似文献
934.
935.
Montero-Campillo MM Rodríguez-Otero J Cabaleiro-Lago EM 《Journal of molecular modeling》2007,13(8):919-926
Methylidencyclopropabenzene (MCPB) 1 and Fulvalenes 2–4 are molecules of special interest due to the relation between structure and aromaticity. The aim of this work was to analyze
this relation and to quantify the aromaticity in 1–4 using different methods. Magnetic properties are directly related with aromaticity; here we studied the magnetic susceptibility
and the anisotropy of the magnetic susceptibility. Nucleus indepedent chemical shift (NICS) and the anisotropy of the induced
current density (ACID) were also employed. Tools of very different nature, geometric indexes HOMA and Bird, were determinated
too for 1–4. All of these measures were found to be in agreement.
Figure Both spatial NICS and ACID plot allow to show the aromaticity/antiaromaticity of a ring 相似文献
936.
Decreased protein tyrosine phosphorylation and membrane fluidity in spermatozoa from infertile men with varicocele 总被引:1,自引:0,他引:1
Buffone MG Brugo-Olmedo S Calamera JC Verstraeten SV Urrutia F Grippo L Corbetta JP Doncel GF 《Molecular reproduction and development》2006,73(12):1591-1599
Varicocele is a prevalent pathology among infertile men. The mechanisms linking this condition to infertility, however, are poorly understood. Our previous work showed a relationship between sperm functional quality and the ability of spermatozoa to respond to capacitating conditions with increased membrane fluidity and protein tyrosine phosphorylation. Given the reported association between varicocele, oxidative stress, and sperm dysfunction, we hypothesized that spermatozoa from infertile patients with varicocele might have a combined defect at the level of membrane fluidity and protein tyrosine phosphorylation. Semen samples from infertile patients with and without grade II/III left varicocele were evaluated for motion parameters (computer-assisted semen analysis [CASA]), hyperactivation (CASA), incidence and intensity of protein tyrosine phosphorylation (phosphotyrosine immunofluorescence and western blotting), and membrane fluidity (Laurdan fluorometry), before and after a capacitating incubation (6 hr at 37 degrees C in Ham's F10/BSA, 5% CO(2)). Spermatozoa from varicocele samples presented a decreased response to the capacitating challenge, showing significantly lower motility, hyperactivation, incidence and intensity of tyrosine phosphorylation, and membrane fluidity. The findings reported in this article indicate that the sperm dysfunction associated to infertile varicocele coexists with decreased sperm plasma membrane fluidity and tyrosine phosphorylation. These deficiencies represent potential new pathophysiological mechanisms underlying varicocele-related infertility. 相似文献
937.
Haobin Hu Haipeng Liang Yufeng Wang Runan Yuan Jiao Sun Lala Zhang Yani Lu 《化学与生物多样性》2021,18(6):e2000947
The ultrasound-assisted extraction (UAE) parameters of total water-soluble polysaccharides (TABPs) from Acanthopanaxbrachypus fruit were optimized by Box-Behnken design (BBD) and response surface methodology (RSM). Physicochemical, structural, and functional properties of TABPs were investigated by chemical analysis, inductively coupled plasma optical emission spectrometry (ICP-OES), high performance liquid chromatography (HPLC), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), water-holding capacity (WHC), oil-holding capacity (OHC), emulsion capacity (EC), emulsion stability (ES), as well as DPPH. and ABTS.+scavenging assays. The results showed that the maximal UAE-yield of TABPs was 3.81±0.18 % under the optimal conditions (ultrasonic power 325 W, extraction temperature 47 °C, extraction time 22 min). TABPs was rich in some beneficial element (Mg, K, Fe, Zn and Na) but little in harmful elements (Hg, Cd, As and Pb), and displayed rough surface with flake-like features and large dents, contained 93.89±0.08 % of total carbohydrate with more different monosaccharides including glucose, galactose, rhamnose, arabinose, mannose, xylose, and uronic acid in a molar ratio of 8.83 : 7.90 : 4.74 : 4.55 : 2.80 : 2.39 : 1.00, respectively. TABPs exhibited broad weight distribution (11.2–133.5 kDa), excellent thermal stability (>280 °C), WHC (0.61±0.08 g water/g sample) and OHC (4.53±0.12 g oil/g sample), as well as higher EC (43.75±1.23 %) and ES (38.32±1.50 %). Furthermore, TABPs also displayed remarkable scavenging activities on DPPH. and ABTS.+ in vitro. These findings provide a scientific basis for the applications of TABPs in functional additives for food, medicine, and cosmetics. 相似文献
938.
鼎湖山酸沉降背景下主要森林类型水化学特征初步研究 总被引:28,自引:0,他引:28
雨水的水质在通过森林后会发生变化.如果雨水是酸性的,这种变化会更加明显.通过一年多时间在鼎湖山主要森林类型采样分析发现,鼎湖山大气降水pH值低,酸雨频率高;阔叶林穿透雨pH值比大气降水高,树干径流和地表水pH值比大气降水低,土壤自然酸化非常严重;混交林穿透雨和地表水酸度比大气降水低,树干径流酸度则大于大气降水;针叶林穿透雨和树干径流都有进一步酸化趋势,但地表水pH值比大气降水高.3种林型比较,阔叶林林冠缓冲能力最强,针叶林土壤缓冲能力最大.3种林型,林内降水和地表水养分N、P、K、Ca、Mg和Na含量除N外都明显高于大气降水.各林型树干径流对养分富集能力强于穿透水,养分在大气降水中的浓度低于在地表水中的浓度.针叶林林内降水比混交林和阔叶林养分含量高,但地表水中养分浓度比后两者低.从地表水的养分浓度看,阔叶林和混交林养分亏损更为严重. 相似文献
939.
In anaerobic wastewater treatment systems, the complex microbial biomass including Archaea and Bacteria can be retained as a biofilm attached to solid supports. The aim of this study was to evaluate the impact of specific properties of support material on early microbial adhesion. Seven different substrata are described in terms of topography and surface energy. Adhesion of a methanogenic consortium to these substrata was tested, the adhesion was quantified as a percentage of the surface area covered and the bacterial and archaeal community structures was assessed by molecular fingerprinting profiles (CE-SSCP). As expected, the overall adhesion on the supports was influenced mainly by total surface energy. Moreover, the adhered communities were different from the parent inocula, including the Archaea/Bacteria ratio. This could have a significant impact on the start-up of anaerobic digesters for which supports favoring Archaea adhesion, responsible for the limiting reaction of the process, should be preferred. 相似文献
940.