胆固醇氧化酶高产菌株的诱变选育及产酶条件优化

在对细脚拟青霉、玫烟色拟青霉、粉拟青霉、香菇、平菇、金针菇等胆固醇氧化酶产生菌初筛的基础上,选择以产酶较高的玫烟色拟青霉作为紫外诱变的出发菌株,筛选出一株相对高产突变菌株MFEC006,其酶活达到了0.548 3 U/mL,比出发菌株提高了154%,经8次传代培养,突变株性质稳定.对MFEC006菌株产酶条件进行优化,得出其最佳产酶条件为:pH为6.5.温度27℃,接种量10%,摇床转速180 r/min.     

Zn^2＋与苹果多酚氧化酶相互作用研究

为探讨苹果多酚氧化酶（简称PPO）的结构与功能关系,应用紫外差示光谱、同步荧光光谱及圆二色性光谱（CD）等生物物理技术和酶活性测定研究了外加Zn^2＋对苹果PPO的分子构象和酶活性的影响。结果表明,微景锌的加入能增加酶的活性和提高α-螺旋含量,当[Zn^2＋]／[PPO]为2．0左右时,苹果PPO活性最高,继续增加[Zn^2＋]／[PPO]比值,酶活性开始下降,比值为2．7以后,Zn^2＋表现了对PPO活性的抑制,α-螺旋含量下降;Zn（Ⅱ）可能与PPO中的组氨酸残基进行了配位,（ImH）σN＋σN→Zn^2＋、（ImH）σ→Zn^2＋、（ImH）π1→Zn^2＋、（ImH）Ⅱπ→Zn^2＋分别为227,241,265,335（nm）;色氨酸和酪氨酸的荧光均受到Zn^2＋的猝灭,但它们的微环境在Zn（Ⅱ）-PPO的相互作用中基本保持不变。     

酶电极法测定肌苷片中肌苷

以固定化核苷磷酸化酶(EC 2.4.2.1)、黄嘌呤氧化酶(EC 1.2.3.2)与过氧化氢电极构成电流型酶电极,研究了肌苷酶电极分析法的各种分析条件及参数,并与紫外分光光度法对比测定了肌苷片中肌苷含量。酶电极法测定结果与紫外法测定结果之间有较好的一致性。采用酶电极法测定肌苷片中肌苷含量专一性高、成本低、分析速度快。     

GOD/Lac生物燃料电池的构建与性能研究

使用葡萄糖糖氧化酶(GOD)和漆酶(Lac)分别做酶生物燃料电池的阳极与阴极,构成了GOD/Lac酶生物燃料电池.首先通过循环伏安法研究了酶生物燃料电池阳极催化剂GOD和阴极催化剂Lac在碳布基底电极上的直接电化学行为,结果表明:GOD与Lac在该修饰电极上均完成了一个直接、可逆的电化学过程,保持了自身的生物学活性,为成功构成GOD/Lac酶生物燃料电池提供一个必要条件.其二,采用葡萄糖作为GOD/Lac酶生物燃料电池的阳极燃料,氧气(O2)作为GOD/Lac酶生物燃料电池的阴极燃料,使用充放电仪测得该GOD/Lac酶生物燃料电池在38.5 mV处的最大输出功率密度为0.108μW·cm-2,电流密度为2.75uμA·cm-2.     

橡椀单宁降解酶特性的研究

借助于没食子酸丙酯为模型化合物作为底物,对一株能抵抗橡椀单宁(鞣花类单宁)生物毒性并能有效降解这种单宁的菌株的降解特性进行了研究。结果表明这株菌不仅具有单宁酶的活性,而且具有多酚氧化酶（PPO）的活性。通过对不同底物对内胞霉PPO酶促反应速度的影响研究证实橡椀单宁的降解不仅与单宁酶有关还与多酚氧化酶有关。     

贮藏时间对超高压处理鲜榨番茄汁品质的影响

以热处理(100℃处理5min)作为对照,评价超高压处理(25℃和400MPa处理30min)鲜榨番茄汁贮藏3个月期间的品质和风味变化规律。结果显示超高压处理的鲜榨番茄汁在2个月的贮藏期内,菌落总数、霉菌和酵母菌数量均在国家食品卫生标准以内;pH值、PPO和POD活性逐渐降低;维生素C含量降低约24%,而热处理的鲜榨番茄汁中维生素C含量降低约96%;超高压处理的鲜榨番茄汁风味更加接近于番茄的原有香气,而热处理引起风味的显著性变化。因此,超高压处理的鲜榨番茄汁在2个月的贮藏期内品质和风味均优于传统热处理番茄汁。     

A simple method for in vivo testing of glandular enzymatic activity on potential precursors of larval defensive compounds inPhratora species (Coleoptera: Chrysomelinae)

The presence of glandular -glucosidase and oxidase-specific activities, and the possible role of phenolglucosides and related compounds as precursors for larval defensive compounds, were directly demonstrated by introducing salicin, saligenin and helicin into the defensive glands ofPhratora species.Ph. tibialis andPh. laticollis that normally secrete endogenously-produced iridoid monoterpenes and do not use phenolglucosides from their food sources as precursors, were able to produce salicyladehyde from helicin when the latter was introduced into the defensive glands.     

Mosquito (Diptera: Culicidae) fauna of the Iranian islands in the Persian Gulf

Mosquitoes of four Iranian islands (Abu-Musa, Hormuz, Larak and Qeshm), Hormozgan Province of southern Iran, were surveyed between 2005 Madison DR, Madison WP. 2005. MacClade 4.08 [Internet]. Sunderland (MA): Sinauer Associates, Inc. http://macclade.org/index.html  [Google Scholar] and 2007 Tamura, K, Dudley, J, Nei, M and Kumar, S. 2007. MEGA4: Molecular Evolutionary Genetics Analysis (MEGA) software version 4.0. Mol Biol Evol., 24: 1596–1599. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]. In 521 specimens collected, 14 species belonging to four genera were identified: Anopheles culicifacies Giles sensu lato (s.l.), An. dthali Patton, An. fluviatilis James s.l., An. stephensi Liston, An. turkhudi Liston, Culex bitaeniorhynchus Giles, Cx. perexiguus Theobald, Cx. pseudovishnui Colless, Cx. quinquefasciatus Say, Cx. sitiens Wiedemann, Cx. theileri Theobald, Cx. tritaeniorhynchus Giles, Culiseta longiareolata (Macquart) and Ochlerotatus (= Aedes) caspius (Pallas) s.l. This is the first record of all of these species on the islands. Cytochrome c oxidase I (COI) barcode sequences were used to confirm the taxonomic identity of An. stephensi, Cx. quinquefasciatus and Oc. caspius s.l. from the islands and mainland of Hormozgan Province, with genetic isolation noted in both Oc. caspius s.l. and Cx. quinquefasciatus samples collected in Abu-Musa Island. Morphological anomalies in island specimens of Cx. quinquefasciatus and Cx. pseudovishnui are discussed.