New (diphenylphosphane)benzoic acid copper(I) derivatives of “scorpionate” ligands with superoxide scavenging activity

New copper(I) complexes have been synthesized from the reaction of CuCl with 4- or 2-(diphenylphosphane)benzoic acid and KH₂B(btz)₂, KHB(btz)₃, NaTp^Me, KpzTp, KpzTp^Me and KH₂B(im)₂(dmac). The complexes obtained have been characterized by elemental analyses and FT-IR in the solid state, and by NMR (¹H and ³¹P{¹H}) and electrospray mass spectroscopy in solution.Chemiluminescence technique was used to evaluate the superoxide scavenging activity of these new copper complexes.     

Effect of N-acetyl- -cysteine on peroxynitrite and superoxide anion production of lung alveolar macrophages in systemic sclerosis

Lung macrophages may play a relevant role in oxidative processes producing both superoxide anion (O(2)(-)) and NO. In this view, an antioxidant therapy can be useful in the treatment of systemic sclerosis (SSc) patients. N-Acetylcysteine (NAC) is able to expand natural antioxidant defenses by increasing intracellular gluthatione concentration and it has been proposed as an antioxidant therapy in respiratory distress syndromes. The aim of our study was to determine whether lung macrophages obtained from SSc patient bronchoalveolar lavage (BAL) express the inducible form of nitric oxide synthase (iNOS) and whether NAC can reduce the peroxynitrite (ONOO(-)) and O(2)(-) production of these cells. Alveolar macrophages were isolated from BAL of 32 patients and used for the immunocytochemical determination of iNOS, and the production of ONOO(-) and O(2)(-) was measured by fluorimetric or spectrophotometric methods, respectively. Lung macrophages obtained from SSc patients expressed a higher level of iNOS compared to healthy subject cells. NAC preincubation (5 x 10(-5)M, 24h) significantly reduced (-21%) the ONOO(-) production in formyl Met-Leu-Phe (fMLP)-activated cells and slightly reduced it under resting conditions, whereas NAC preincubation was unable to modify the release of O(2)(-) both in basal condition and in fMLP-stimulated cells. We conclude that since SSc lung macrophages express high levels of iNOS and produce a significant quantity of ONOO(-), NAC administration reduces ONOO(-) production and can be an useful treatment to alleviate SSc symptoms.     

紫苏挥发油抑制皮肤癣菌及的作用

用水蒸气蒸馏法得到紫苏挥发油 ,进行抑菌以及抑制超氧阴离子自由基的实验。结果表明 :紫苏挥发油对红色毛癣菌 ,石膏样小孢子癣菌 ,絮状表皮癣菌有较好的抑菌作用 ,并能有效的抑制O　·2 的生成     

美国白蛾核型多角体病毒超氧化物歧化酶基因的序列分析和表达

根据测序结果 ,HcNPVsod的核苷酸序列与BmNPVsod的完全一致 ,与AcNPVsod的核苷酸序列相比 ,同源性达到 97 2 % ;推测HcNPVsod编码 1 51个氨基酸 ,与BmNPVsod的完全一致 ,与AcNPVsod编码的氨基酸相比 ,有三个氨基酸的差别。按基酸序列分析表明 ,HcNPVSOD蛋白中含有对SOD结构和活性必需的氨基酸残基 ,在HcNPVsod中均是保守的。SOD活性测定表明酶活为 1 47 0 9U/mL菌液     

Effect of Cold Hardening on SOD and Glutathion Reductase Activities and on the Contents of the Reduced Form of Glutathion and Ascorbic Acid in Rice and Cucumber Seedlings

Rice and cucumber seedlings were employed in the study on changes of superoxide dismatase (SOD) and glutathion reductase (GR) activities, the contents of the reduced form of glutathion (GSH) and ascorbic acid (ASA) in leaves and the chilling resistance as well as the level of lipid peroxidation products after cold hardening and chilling stress under light. The seedlings hardened under a day/night temperature variation of 15 ℃/10 ℃ and photon flux density (PFD) of 250μmol · m-2 · s-1 for 12 h/d indicated an increase of the activities of SOD and GR, and the contents of GSH and AsA. The resistance of the seedlings to chilling and light stress was enhanced by cold hardening. Under the stress condition, the stabilities of SOD and GR activities, and contents of GSH and AsA in hardened seedlings were higher than those in the unhardened seedlings; the lipid peroxidation was also less than that in the latter. It was thus concluded that cold-hardening under appropriate light leads on to the enhancement of function of membrane protective system and increase of cell membrane stability which is an important part of chilling-resistance mechanism in the plant.     

芦苇耐脱水能力的生理生态学分析

甘肃省河西走廊分布有不同生态环境的芦苇,包括沼泽芦苇、盐化草甸芦苇和沙丘芦苇。盐化草甸芦苇和沙丘芦苇表观出很强的耐脱水能力。 测定与植物耐脱水能力相关的SOD、CAT和POD活力,表现为SOD活力以沙丘芦苇最高,盐化草甸芦苇次之,沼泽芦苇最低,但CAT和POD则以沼泽芦苇高于其它生境芦苇。用聚丙烯酰胺垂直板电泳方法分析这3种酶同工酶谱,结果表明,3种不同生境芦苇的SOD同工酶谱基本相同,均有9条酶带,但沙丘芦苇和盐化草甸芦苇的CAT和POD同工酶带数比沼泽芦苇分别增多3条和2条。这些结果证明,芦苇在自然选择压力下形成的耐脱水能力与基因调控的酶多型性相关。     

维生素E对三氯乙烯急性染毒大鼠肝脏脂质过氧化与抗氧化酶的影响

本文观察了用抗氧化剂维生素E预处理后,三氯乙烯(3000mg/kg B-W-) 一次性经口染毒24h 大鼠肝脏的超氧化物歧化酶、谷胱甘肽过氧化物酶等抗氧化酶活力及丙二醛含量的变化,结果表明三氯乙烯染毒组肝脏中丙二醛含量、超氧化物歧化酶活力及血清谷丙转氨酶、谷草转氨酶活力均高于对照组(P< 0-01) ;而维生素E干预组的丙二醛含量、超氧化物歧化酶活力及血清谷丙转氨酶、谷草转氨酶活力均分别低于三氯乙烯染毒组(P< 0-01) ,说明三氯乙烯急性染毒可引起肝脏脂质过氧化反应及肝损害,肝脏超氧化物歧化酶活力升高可能是机体受自由基及脂质过氧化反应刺激而诱导产生的一种适应性反应,维生素E对三氯乙烯所致的肝损害有一定的保护作用。     

烟草—烟草花叶病毒互作中的质膜NADPH氧化酶

以NN烟草(NicotianatabacumL.)品种“SamsunNN”(与烟草花叶病毒(TMV)发生非亲和互作)和普通烟草(N.tabacumL.)“3002”品种(与TMV发生亲和互作)叶片为材料,采用差速离心法和两相法制备密闭的正向型质膜(PM)囊泡。用SOD敏感的依赖于NADPH的Cytc的还原表示质膜NADPH氧化酶产生超氧阴离子(O-·2)的活性。加入0.01%TritonX_100可使酶活性提高约80%,证明NADPH结合位点在质膜电子载体蛋白胞质结构域上,而O-·2在质膜外侧生成,在反应过程中发生了跨质膜的电子传递。质膜NADPH氧化酶的活性可部分地被哺乳动物NADPH氧化酶的专一性抑制剂DPI(diphenyleneiodonium)抑制,最大抑制达70%。受TMV侵染后,NN烟草NADPH氧化酶活性显著升高,而普通烟草的酶活性基本不变。对质膜NADPH氧化酶在烟草_TMV互作早期活性氧生成和启动过敏反应中的作用展开讨论     

Hydrophobicity-tuned anion responsiveness underlies endosomolytic cargo delivery mediated by amphipathic vehicle peptides

Peptide conformation can change subject to environment cues. This concept also applies to many cationic amphipathic peptides (CAPs) known to have cell membrane lytic or penetrative activities. Well-conditioned CAPs can match the properties of the target membrane to support their intended biological functions, e.g., intracellular cargo delivery; however, the intricacy in such conditioning surpasses our current understanding. Here we focused on hydrophobicity, a key biophysical property that dictates the membrane activity of CAPs, and applied a structure–function strategy to evolve a template peptide for endosomolytic cargo delivery. The template was subjected to iterative adjustment to balance hydrophobicity between its N-terminal linear and C-terminal helical domains. We demonstrate that the obtained peptide, LP6, could dramatically promote cargo cell entry and facilitate cytosolic delivery of biomacromolecules such as FITC-dextran, saporin, and human IgG. Among the evolved peptide series, LP6 has low cytotoxicity and moderate hydrophobicity, exhibits maximum change in helical conformation in response to negatively charged phospholipids, and also shows an apparent aggregational behavior in response to sialic acid enrichment. These attributes of LP6 collectively indicate that its anion-responsive conformational change is a critical underlining of its endosomolytic cargo delivery capability. Our results also suggest that modulation of hydrophobicity serves as a key to the precise tuning of CAP''s membrane activity for future biomedical applications.     

Enantioselective anion exchangers based on cinchona alkaloid‐derived carbamates: Influence of C8/C9 stereochemistry on chiral recognition

Four diastereomeric chiral stationary phases (CSPs) based on quinine, quinidine, epiquinine, and epiquinidine tert‐butyl carbamate selectors were synthesized and evaluated under ion exchange HPLC conditions with a set of racemic N‐acylated and N‐oxycarbonylated α‐amino acids as selectands. The enantioseparation potential of quinine‐ and quinidine‐derived CSPs proved to be far superior to that of their C₉‐epimeric congeners. The absolute configuration of C₉ stereogenic center of the cinchonan backbone of these selectors was identified as the structural feature controlling the elution order. Guided by an X‐ray structure of a most favorable selector–selectand complex and the observed chromatographic enantioseparation data, a chiral recognition model was advanced. The contributions of ion‐pairing, π–π donor–acceptor, hydrogen bonding and steric interactions were established as crucial factors. Chirality 11:522–528, 1999. © 1999 Wiley‐Liss, Inc.