稀土Ho-吲哚-3-乙酸配合物的合成及其生物活性的研究

以吲哚-3-乙酸为配体,合成了稀土钬的配合物。利用元素分析、红外光谱(IR)、热重-差热分析(TG-DTG)和荧光光谱(FS)等分析手段对配合物的组成和光学等性质进行了分析与表征,推测配合物的通式为Ho(L)3.2H2O;通过对荧光光谱的研究表明,稀土钬配合物具有较好的荧光性能;通过对其生物活性的表征说明吲哚乙酸与稀土硝酸盐在形成稀土配合物后,对植物的生长起到了协同促进作用。     

吡唑啉酮铜配合物P-FAH-Cu-phen对金黄色葡萄球菌的转录组影响分析

【背景】金黄色葡萄球菌是目前食品和临床引起感染的重要病原菌,迫切需要开发新型抗菌药物。【目的】分析吡唑啉酮铜配合物P-FAH-Cu-phen对金黄色葡萄球菌的转录组影响和主要代谢信号通路。【方法】采用液体稀释法测定P-FAH-Cu-phen作用金黄色葡萄球菌的最低抑菌浓度(minimum inhibitory concentration, MIC)和最低杀菌浓度(minimum bactericidal concentration, MBC)。将终浓度2 μg/mL的配合物分别作用于对数生长期的金黄色葡萄球菌30 min和2 h,进行转录组测序及分析。【结果】 P-FAH-Cu-phen作用金黄色葡萄球菌的MIC和MBC分别为2 μg/mL和4 μg/mL。与空白对照相比,配合物处理细菌30 min后,其差异基因共有356个,其中上调表达180个、下调表达176个;配合物处理细菌2 h后,其差异基因共有23个,其中上调表达3个、下调表达20个。差异基因功能主要富集于膜的组成部分、细胞质、质膜、ATP结合、发病机制、金属离子结合、组氨酸生物合成过程、DNA结合、水解酶活性、跨膜转运蛋白活性、硝酸盐同化、硝酸盐代谢过程、硝酸还原酶复合物、硝酸还原酶活性等。差异基因涉及的信号通路主要有双组分系统、群体感应、氮代谢、三羧酸循环、氨基酸代谢等。【结论】影响细菌质膜组成、毒素生成、生物膜形成、细胞壁合成、能量代谢等可能是吡唑啉酮铜配合物P-FAH-Cu-phen对金黄色葡萄球菌的主要抑菌作用。研究为揭示吡唑啉酮铜配合物抑制金黄色葡萄球菌分子机制提供了理论依据。     

DL-α-白氨酸与稀土硝酸盐固体配合物的合成及性质

用白氨酸分别和三种稀土硝酸盐在有机溶剂中首次合成了三种相应的1:2型固体配合物,经化学分析和元素分析确定了其组成为RE(Leu)_2(NO_3)_3·2H_2O(RE=Ce,Nd,Sm;Leu=DL-α-Leucine)。并通过X—粉晶衍射、红外光谱、TG—DTG和电导等对其性质进行了讨论。     

Cu~(2+)-ASP配合物的合成及分析

研究了金属铜离子与天冬氨酸 (ASP)配合物的合成方法[1,2 ] ,采用X射线光谱对配合物进行了分析鉴定 ,结果表明铜离子与天冬氨酸能形成配合物。     

水净化新进展:清除地下水中的硝酸盐

尽管一再努力降低危害身体和造成环境问题的硝酸盐的有害浓度,欧美的多数地下水仍受到其污染。现在研究人员已发现利用固定化酶除去硝酸盐的途径,Mobitec GmbH和Agrecol Corp.这两家公司正努力使这项技术商业化。上述方法是利用电-生物反应器,其中有固定酶的尼龙样多聚物基质,固定化酶可将硝酸盐转变为亚     

S-甲基二硫代肼基甲酸的西夫碱双铜配合物的合成及其在双层脂膜上的电子传递

合成了S-甲基二硫代肼基甲酸的西夫碱双铜配合物并用各种物理方法对其进行了结构鉴定。生物试验表明配合物对各类微生物具有一定抑制作用。用循环伏安法研究了经双铜配合物修饰的双层脂膜(bilayer lipid membrane,BLM)上的氧化还原反应,表明配合物在膜内起电子递体的作用。     

水飞蓟宾微量元素配合物的合成及其抗菌抗肿瘤活性研究

合成水飞蓟宾钙、铁、锌、硒、铬、钴配合物6个中药新药,采用IR、UV、Lc-MS、EDTA络合滴定和元素分析仪表征配合物化学结构,结果显示合成的配合物配位比为2∶1(水飞蓟宾∶微量元素),且小鼠急性毒性实验显示6个配合物均无明显毒性。采用倍比稀释法测定配合物对枯草杆菌等9种致病菌的抑制活性,发现其最小抑菌浓度MIC均低于水飞蓟宾,抗菌活性提升至2～4倍;采用MTT法测定配合物对5株肿瘤细胞增殖的影响,发现其半数抑制浓度IC_(50)均小于水飞蓟宾,抗肿瘤活性提升至1.11～1.53倍。综上,水飞蓟宾与微量元素形成配合物后,其抗菌及抗肿瘤活性均增强。     

DL─蛋氨酸的希夫碱的铜（Ⅱ）、锌（Ⅱ）配合物的抑菌作用

合成ＤＬ─蛋氨酸与邻香草醛缩合成铜（Ⅱ）、锌（Ⅱ）配合物,经化学分析、电子、红外光谱、热分析测定,对配合物进行了组成和结构分析。测定了配合物对金黄色葡萄球菌、大肠杆菌和枯草杆菌的抑制作用。     

镍离子──氨基酸配合物的合成及其分析

本文着重研究了镍离子与两种氨基酸配合物的合成,并对配合物的结构进行了分析。     

壳聚糖Fe（Ⅲ）配合物的合成、表征及抑菌性能

合成了壳聚糖Fe(Ⅲ)配合物,利用IR、UV、和TG-DTA对配合物进行了表征.研究了壳聚糖及壳聚糖铁(Ⅲ)配合物对常见的两种细菌(大肠杆菌、金黄色葡萄球菌)的抑菌性能.结果表明:水溶性的壳聚糖在配合前后,其结构表征发生了一定的变化,并且壳聚糖铁(Ⅲ)配合物的抑菌性能比水溶性壳聚糖本身显著提高(P＜0.05).     

Evidence for a relationship between mitochondrial Complex I activity and mitochondrial aldehyde dehydrogenase during nitroglycerin tolerance: Effects of mitochondrial antioxidants

The medical use of nitroglycerin (GTN) is limited by patient tolerance. The present study evaluated the role of mitochondrial Complex I in GTN biotransformation and the therapeutic effect of mitochondrial antioxidants. The development of GTN tolerance (in rat and human vessels) produced a decrease in mitochondrial O(2) consumption. Co-incubation with the mitochondria-targeted antioxidant mitoquinone (MQ, 10(-6)mol/L) or with glutathione ester (GEE, 10(-4)mol/L) blocked GTN tolerance and the effects of GTN on mitochondrial respiration and aldehyde dehydrogenase 2 (ALDH-2) activity. Biotransformation of GTN depended on the mitochondria being functionally active, particularly mitochondrial Complex I. Tolerance induced mitochondrial ROS production and oxidative stress, though these effects were not detected in HUVECρ(0) cells or Complex I mutant cells. Experiments performed to evaluate Complex I-dependent respiration demonstrated that its inhibition by GTN was prevented by the antioxidants in control samples. These results point to a key role for mitochondrial Complex I in the adequate functioning of ALDH-2. In addition, we have identified mitochondrial Complex I as one of the targets at which the initial oxidative stress responsible for GTN tolerance takes place. Our data also suggest a role for mitochondrial-antioxidants as therapeutic tools in the control of the tolerance that accompanies chronic nitrate use.     

The occurrence and control of nitric oxide generation by the plant mitochondrial electron transport chain

The plant mitochondrial electron transport chain (ETC) is bifurcated such that electrons from ubiquinol are passed to oxygen via the usual cytochrome path or through alternative oxidase (AOX). We previously showed that knockdown of AOX in transgenic tobacco increased leaf concentrations of nitric oxide (NO), implying that an activity capable of generating NO had been effected. Here, we identify the potential source of this NO. Treatment of leaves with antimycin A (AA, Q_i‐site inhibitor of Complex III) increased NO amount more than treatment with myxothiazol (Myxo, Q_o‐site inhibitor) despite both being equally effective at inhibiting respiration. Comparison of nitrate‐grown wild‐type with AOX knockdown and overexpression plants showed a negative correlation between AOX amount and NO amount following AA. Further, Myxo fully negated the ability of AA to increase NO amount. With ammonium‐grown plants, neither AA nor Myxo strongly increased NO amount in any plant line. When these leaves were supplied with nitrite alongside the AA or Myxo, then the inhibitor effects across lines mirrored that of nitrate‐grown plants. Hence the ETC, likely the Q‐cycle of Complex III generates NO from nitrite, and AOX reduces this activity by acting as a non‐energy‐conserving electron sink upstream of Complex III.     

Lanthanide nitrate complexes of 4-N-(2′-Hydroxy-1 ′-naphthylidene)-aminoantipyrine

Lanthanide nitrates form with 4-N-(2′-hydroxy-l′- naphthylidene)aminoantipyrine (HNAAP) complexes of the type [Ln(HNAAP)₂(NO₃)₃] (where Ln = La, Pr, Nd, Sm, Gd, Tb, Dy, Ho and Y). The IR spectra of these complexes show that HNAAP acts as a bidentate neutral ligand and nitrate group is coordinated monodentately. The electronic spectra of the Nd complex show reasonable covalency in the metal-ligand bond. The magnetic moments of these complexes are in better agreement with the Van Vleck values. All these complexes are thermally stable up to200 °C.     

Nitrogen Requirement of Iron-Oxidizing Thiobacilli for Acidic Ferric Sulfate Regeneration

Ammonium was shown to be a limiting nutrient for iron oxidation in cultures of Thiobacillus ferrooxidans. In addition, one strain was also able to assimilate nitrate, but not nitrite, for growth and coupled iron oxidation. Some amino acids (0.5 mM) were tested as a source of nitrogen; none clearly stimulated bacterial activity and inhibition was commonly encountered. Complex nitrogenous compounds were inhibitory at high concentrations (0.1 to 0.5%, wt/vol) and, at low concentrations, some clearly stimulated the bacterial iron oxidation in ammonium-limited cultures. Enhancement of iron oxidation by these compounds was also observed in ammonium-unlimited cultures, suggesting their possible role in providing trace nutrients and possibly carbon for the bacteria.     

Ventrolateral nucleus of the cat thalamus and its connection with field 4 of the cerebral cortex

By means of silver nitrate impregnation after Fink-Heimer and Golgi-Kopsch structural peculiarities have been revealed in the neurons of the ventral lateral nucleus (VL) of the cat thalamus and its connections with the motor cortex. The results of the observations demonstrate a complex morphological organization of the VL. It makes reciprocal connections with the field 4 of the motor cortex. Terminal fibers from the VL end in the layers I, III, V and VI of the field 4 gamma and in the whole thickness of the fundal field anatomically having no layers. No degenerating fibers are found after destruction in the fields 4 delta and 4 sfu. Basing on measurements of neuronal nuclei in the VL two cell populations are revealed, that demonstrates presence of two types of the neurons in the VL--large relay and small short axonal, each of them having several varieties. Complex synaptic contacts in the VL in the form of serial synapses and triads are also demonstrated.     

Changes in bacterial community structure correlate with initial operating conditions of a field-scale denitrifying fluidized bed reactor

High levels of nitrate are present in groundwater migrating from the former waste disposal ponds at the Y-12 National Security Complex in Oak Ridge, TN. A field-scale denitrifying fluidized bed reactor (FBR) was designed, constructed, and operated with ethanol as an electron donor for the removal of nitrate. After inoculation, biofilms developed on the granular activated carbon particles. Changes in the bacterial community of the FBR were evaluated with clone libraries (n=500 partial sequences) of the small-subunit rRNA gene for samples taken over a 4-month start-up period. Early phases of start-up operation were characterized by a period of selection, followed by low diversity and predominance by Azoarcus-like sequences. Possible explanations were high pH and nutrient limitations. After amelioration of these conditions, diversification increased rapidly, with the appearance of Dechloromonas, Pseudomonas, and Hydrogenophaga sequences. Changes in NO₃, SO₄, and pH also likely contributed to shifts in community composition. The detection of sulfate-reducing-bacteria-like sequences closely related to Desulfovibrio and Desulfuromonas in the FBR have important implications for downstream applications at the field site.     

复合菌剂调控连作当归根围土壤养分及对产量的影响

【背景】连作可引起微生物群落结构失调,导致土壤环境恶化、养分循环不畅、当归[Angelica sinensis (Oliv.) Diels]产量降低,通过现代微生物技术改良土壤、消减连作障碍势在必行。【目的】于大田条件下,研究施用复合菌剂对当归根围土壤酶活、速效养分及产量的影响,明确增产机制,改进增产措施。【方法】利用溶磷圈法检测不同菌株溶磷活性、乙炔还原法检测固氮活性、试剂盒法检测过氧化物酶和硝化能力;复合菌剂T1[荧光假单胞菌(Pseudomonas fluorescens)CBS5、产碱假单胞菌(Pseudomonas alcaligenes) CBS7、嗜冷假单胞菌(Pseudomonas extremaustralis)CBSB、生枝动胶菌(Zoogloea ramigera) CBS4]和T2 (荧光假单胞菌CBS5、产碱假单胞菌CBS7、嗜冷假单胞菌CBSB)及对照CK (无菌马铃薯葡萄糖肉汤培养基)分别处理连作当归,分光光度法测定根围土壤及根中养分循环、转化相关酶活,氮、磷、钾速效养分含量;常规方法测产量;统计软件进行相关数据方差分析和主成分分析。【结果】产碱假单胞菌C...     

Laser-induced breakdown spectroscopic study of ammonium nitrate plasma

We present the optical emission studies of the ammonium nitrate plasma produced by the fundamental (1064 nm) and second (532 nm) harmonics of a Q-switched Nd: YAG laser. The target material was placed in front of the laser beam in an open atmospheric air. The spectrum reveals numerous transitions of neutral nitrogen. We have studied the spatial behavior of the plasma temperature (T _e ) and electron number density (N _e ) determined using the Boltzmann plot method and Stark broadened line profiles, respectively. Besides, we have studied the variation of the plasma parameters as a function of the laser irradiance.     

NDUFS4: Creation of a mouse model mimicking a Complex I disorder

The Complex I NADH dehydrogenase–ubiquinone–FeS 4 (NDUFS4) subunit gene is involved in proper Complex I function such that the loss of NDUFS4 decreases Complex I activity resulting in mitochondrial disease. Therefore, a mouse model harboring a point mutation in the NDUFS4 gene was created. An embryonic lethal phenotype was observed in homozygous (NDUFS4^?/?) mutant fetuses. Mitochondrial function was impaired in heterozygous animals based on oxygen consumption, and Complex I activity in NDUFS4 mouse mitochondria. Decreased Complex I activity with unaltered Complex II activity, along with an accumulation of lactate, were consistent with Complex I disorders in this mouse model.     

Sequence analysis of bacterial redox enzyme maturation proteins (REMPs)

The twin-arginine protein transport (Tat) system is a remarkable molecular machine dedicated to the translocation of fully folded proteins across energy-transducing membranes. Complex cofactor-containing Tat substrates acquire their cofactors prior to export, and substrate proteins actually require to be folded before transport can proceed. Thus, it is very likely that mechanisms exist to prevent wasteful export of immature Tat substrates or to curb competition between immature and mature substrates for the transporter. Here we assess the primary sequence relationships between the accessory proteins implicated in this process during assembly of key respiratory enzymes in the model prokaryote Escherichia coli. For each respiratory enzyme studied, a redox enzyme maturation protein (REMP) was assigned. The main finding from this review was the hitherto unexpected link between the Tat-linked REMP DmsD and the nitrate reductase biosynthetic protein NarJ. The evolutionary link between Tat transport and cofactor insertion processes is discussed.