用激光解吸电离飞行时间质谱快速测定1H-2,3-二氢-1-吡咯里嗪酮衍生物的相对分子质量

采用激光解吸电离飞行时间质谱 (LDI TOF MS)快速测定了 1H 2 ,3 二氢 1 吡咯里嗪酮衍生物相对分子质量 ,初步总结了该类化合物的质谱规律 .实验中不需加入基质 ,实测值与理论计算值相吻合.

Solvation dynamics of tryptophan in water-dimethyl sulfoxide binary mixture: In search of molecular origin of composition dependent multiple anomalies

Experimental and simulation studies have uncovered at least two anomalous concentration regimes in water-dimethyl sulfoxide (DMSO) binary mixture whose precise origin has remained a subject of debate. In order to facilitate time domain experimental investigation of the dynamics of such binary mixtures, we explore strength or extent of influence of these anomalies in dipolar solvation dynamics by carrying out long molecular dynamics simulations over a wide range of DMSO concentration. The solvation time correlation function so calculated indeed displays strong composition dependent anomalies, reflected in pronounced non-exponential kinetics and non-monotonous composition dependence of the average solvation time constant. In particular, we find remarkable slow-down in the solvation dynamics around 10%-20% and 35%-50% mole percentage. We investigate microscopic origin of these two anomalies. The population distribution analyses of different structural morphology elucidate that these two slowing down are reflections of intriguing structural transformations in water-DMSO mixture. The structural transformations themselves can be explained in terms of a change in the relative coordination number of DMSO and water molecules, from 1DMSO:2H(2)O to 1H(2)O:1DMSO and 1H(2)O:2DMSO complex formation. Thus, while the emergence of first slow down (at 15% DMSO mole percentage) is due to the percolation among DMSO molecules supported by the water molecules (whose percolating network remains largely unaffected), the 2nd anomaly (centered on 40%-50%) is due to the formation of the network structure where the unit of 1DMSO:1H(2)O and 2DMSO:1H(2)O dominates to give rise to rich dynamical features. Through an analysis of partial solvation dynamics an interesting negative cross-correlation between water and DMSO is observed that makes an important contribution to relaxation at intermediate to longer times.

高活性壳聚糖的制备及其抑菌特性的研究

本文通过探索影响脱乙酰化度的因素，成功地制取了高脱乙酰化度的可溶性壳聚糖，经辐射处理后，得到高活性的壳聚糖，并就其对金黄色葡萄球菌、大肠杆菌、酵母菌和霉菌生长抑制作用及其抑菌活性片段分子量等特性进行了研究。干蟹粉经脱钙，脱蛋白，脱色后，得到甲壳质粗品，经50%NaOH于110 ℃ 脱乙酰1h, 重复一次，用2%HAc纯化，可得到脱乙酰化度达95%的壳聚糖。壳聚糖经辐射处理后抑菌作用效果明显增强，对金黄色葡萄球菌和大肠杆菌的最低抑菌浓度分别比辐射前提高了100倍和10倍，对黑曲霉等6种霉菌的抑制用较辐射前有不同和度的提高。0.02g/l浓度下对酵母菌行长抑制达72h。辐射强度、辐射剂量、壳聚糖脱乙酰化度等因素对辐射处理后壳聚糖的活性有较大影响，脱乙酰化度达95%以上的壳聚糖在5kGy·h~(-1)强度下，经100kGy辐射剂量处理可得到高活性壳聚糖。当壳聚糖脱乙酰化度低于95%，或辐射强度降低，或辐射剂量增加或减少时，处理后的壳聚糖活性明显降低。辐射处理能显著提高聚糖的溶解性，特别是壳聚糖的水溶性。活性壳聚糖起抑菌作用的分子片段随作用菌种的不同而有所不同，对金黄色葡萄球菌的生长起抑制作用的是10万以上的某些（或某个）分子片段；对于大肠杆菌，10万以上以及3～5万的某些（或某个）分子片段均有明显的抑制作用，而其它范围的分子片段几乎没有抑制作用。比较壳聚糖抑制金黄色葡萄球菌和大肠杆菌生长的活性分子片段发现，其分子量对壳聚糖的抑菌活性强弱有明显影响。

真鲷(Pagrosomus major)胚胎冷冻保存损伤机理及冷冻精子遗传物质稳定性研究

本文对真鲷心跳期胚胎对5种常用渗透性抗冻剂（DMSO、甘油、甲醇、丙二醇、乙二醇）和3种非渗透性抗冻剂（PVP、PEG-8000、蔗糖）的耐受性进行了研究。渗透性抗冻剂分6个浓度梯度（5%；10%；15%；20%；25%；30%）和3个时间组（10min；30min；1h）。非渗透性抗冻剂中，PVP、PEG-8000分3个浓度梯度（5%、10%、15%）和2个时间组（10min、30min），蔗糖为4个浓度梯度（5%、10%、15%、20%）和2个时间组（10min、30min）。实验结果表明，在渗透性抗冻剂组中，浓度为5%的处理组的孵化率（>90%）与对照组差异均不显著，随着抗冻剂浓度增大及处理时间的延长，真鲷心跳期胚胎的孵化率显著下降（P<0.05），在最高浓度的最长处理时间中胚胎孵化率均降到了0。总体上，真鲷心跳期胚胎对五种渗透性抗冻剂的耐受性从小到大依次为：甲醇 < 甘油 < 乙二醇 < DMSO < 丙二醇。对影响胚胎孵化率的三个因素（抗冻剂、浓度、时间）进行的因素效应分析结果表明，三种因素对孵化率的影响显著（P<0.05），并且浓度效应 > 时间效应 > 抗冻剂效应。在非渗透性抗冻剂组中，蔗糖组胚胎孵化率未呈显著变化；PVP组随着浓度及时间的增大，孵化率显著下降（P<0.05）；PEG-8000组随着浓度增大孵化率显著下降（P<0.05），但在两个时间组间差异不显著。相同处理情况下PEG-8000对真鲷心跳期胚胎的毒性要小于PVP。因素效应分析比较结果表明仅时间效应不显著，且抗冻剂效应 > 浓度效应 > 时间效应。 对所用各种抗冻剂进行了渗透压测量，实验中使用的渗透性抗冻剂（5%-30%）的渗透压值在959-7980mOsm/kg之间，均高于使用海水的渗透压值（919mOsm/kg）；使用的非渗透性抗冻剂的渗透压值在316-1040mOsm/kg之间，除20%蔗糖渗透压值（1040mOsm/kg）高于海水外，其他非渗透性抗冻剂的渗透压值均要低于海水。对孵化率与相应的溶液渗透压值进行相关回归分析结果表明，渗透性抗冻剂的渗透压与孵化率呈显著的负相关（P<0.05），而非渗透性抗冻剂的渗透压与孵化率相关不显著。渗透性抗冻剂组的回归分析结果表明，二次方程的曲线拟合度最高，得到的回归方程分别为：Y10min = -2×10-8X2 10min - 6×10-5 X 10min + 1.5635 （R2 = 0.713），Y30min= 5×10-8X2 30min－0.0007 X 30min + 2.097（R2 = 0.681），Y1h = 7×10-8X2 1h－0.0008 X 1h+ 2.0397（R2= 0.725）。 在真鲷胚胎对抗冻剂耐受性实验的基础上，挑选五种抗冻剂--10%DMSO、5%甘油、10%甲醇、20%丙二醇、10%乙二醇，浸泡真鲷心跳期胚胎30min后，分别以超速（130℃/min）、快速（20℃/min）、慢速（3℃/min）的速度降温并使用低温显微镜进行观察，依次记录Toif（油球结冰）、Teif（胚胎外部结冰）、Tiif（胚胎内部结冰）等结冰点，Toif值在-9~-23℃之间；Teif值在-21~-35℃之间；Tiif值在-21~-52℃之间。结冰顺序为先油球结冰，然后胚胎外部结冰随之内部马上瞬间变黑形成内部冰晶。随着降温速度的提高，各结冰温度值显著下降。各抗冻剂之间的Teif及Tiif值不同，Toif值之间没有显著差异。对两种玻璃化冷冻方法进行模拟观察，发现胚胎冰晶形成的顺序与非玻璃化过程不同--先内部结冰然后逐渐蔓延至外部形成外部冰晶，而且模拟玻璃化的内部结冰温度Tiif值（-52.56℃）显著（P<0.05）低于使用低浓度的同种抗冻剂超速降温组的Tiif值（-40.11℃）。在快速及慢速降温组中，20%丙二醇组的Tiif要显著的低于其他组（P<0.05）；在超速降温中，甲醇组的Tiif值要显著的低于其他组（P<0.05）。在Tiif小于30℃的实验组中获得形态完整胚胎的比例平均仅有30.77%；在Tiif大于30℃的实验组中获得形态完整胚胎的平均比例高达70.37%，模拟玻璃化组达到100%。各抗冻剂之间，复温后胚胎形态完整率10%甲醇组最高（77.78%）；其次依次为10%乙二醇（66.67%）、20%丙二醇（55.56%）和10%DMSO（55.56%）；5%甘油组最低（11.11%）；推测甲醇的对胚胎的渗透效果要好于其他组。综上推测：使用丙二醇、甲醇作为抗冻剂以及玻璃化冷冻保存方法对真鲷心跳期胚胎超低温保存也许较为合适。 我们对低温保存的真鲷精子核DNA损伤进行了研究以期为下一步胚胎遗传物质稳定性研究提供参考依据。研究方法为单细胞凝胶电泳（SCGE），针对研究对象，在实验过程中对传统的碱性单细胞凝胶电泳在铺胶方法、电泳条件等进行了改进。对精子细胞进行预处理，在碱性电泳液中使核DNA双链解链变性后电泳，EB染色lOmin后，在荧光显微镜下观察，每次随机观察50个左右的核DNA。结果表明，对荧光显微镜下观察到的精子核按彗尾长度及荧光强度划分等级，出现损伤的精子核DNA的损伤程度主要为轻度损伤和中度损伤，很少见有完全损伤的真鲷精子核。经5%、10%、18%、20%、25%、30%DMSO冷冻保存后的精子彗星率分别为33.47％ ± 8.95％; 35.91％ ± 19.44％; 48.95％ ± 8.90％; 43.33％ ± 11.19％; 55.80％ ± 38.94％。鲜精彗星率为31.43 ％ ± 2.68％。对比真鲷冷冻精液与新鲜精液的精子DNA的损伤状况，表明仅用30％ DMSO冷冻精子DNA损伤状况与鲜精差异显著(P<0.05)。 综上所述，渗透性抗冻剂对胚胎的毒性与其渗透压值呈显著的负相关关系。丙二醇对真鲷心跳期胚胎毒性最小，甲醇较其他抗冻剂能更好的渗透入胚胎；玻璃化方法能显著降低Tiif值并能更好的保持超低温保存后胚胎的形态完整性，因此，使用丙二醇、甲醇作为抗冻剂以及玻璃化冷冻保存方法对真鲷心跳期胚胎超低温保存也许较为合适。常规使用的用于超低温保存真鲷精子的DMSO（浓度<15%）不会对精子核物质稳定性造成明显影响。由于胚胎较精子结构要复杂许多，对于真鲷胚胎损伤机理的研究还有大量工作可以开展。

Dihydroisocoumarin from Xyris pterygoblephara active against dermatophyte fungi

The ethanol extract from Xyris pteygoblephara aerial parts was evaluated against five microorganism strains, by the microdilution and agar diffusion methods. Extract fractionation led to the isolation of three compounds, whose structures were assigned by spectrometric data (113 and 2D NMR, IR, MS and UV) as (3R,4R)-(-)-6-methoxy-3,4-dihydro-3-n-pentil-4-acethoxy-1H-2-benzopyran-1-one (1), moronic acid and quercetin. The absolute configuration of I was defined by circular dichroism spectroscopy and comparison with data reported for other dihydroisocoumarins. Assay of 1 (100 mu g/disc) by the agar diffusion method against clinical isolates of the dermatophytes Epidermophyton floccosum (inhibition zone, mm +/- s.d.: 4.5 +/- 0.8), Trichophyton mentagrophytes (4.8 +/- 0.4) and Trichophyton rubrum (10.2 +/- 0.8) revealed similar inhibition zones to the positive control amphotericin B (32 mu g/disc; 5.0 +/- 0.2; 5.0 +/- 0.6 and 8.8 +/- 1.2, respectively). The result corroborates the ethnomedical use of Xyris species to treat dermatitis. (C) 2007 Elsevier Ltd. All rights reserved.

Synthesis and thermal study of the barium complexes with 8-hydroxyquinolinate derivatives

In this present work, barium ion was reacted with different ligands which are 5,7-dibromo, 5,7-dichloro, 7-iodo and 5-chloro-7-iodo-8-hydroxyquinoline, in acetone/ammonium hydroxide medium under constant stirring and the obtained compounds were as follows: (I) Ba[(C9H4ONBr2)(2)].1.5H(2)O; (II) Ba[(C9H4ONCl2)(OH)]. 1H(2)O; (III) Ba[(C9H5ONI)(2)]. 1H(2)O and (IV) Ba[(C9H4ONICl)(2)]. 5H(2)O, respectively. The compounds were characterized by elemental analysis, infrared absorption spectrum (IR), inductively coupled plasma spectrometry (ICP), simultaneous thermogravimetry-differential thermal analysis (TG-DTA) and differential scanning calorimeter (DSC).The final residue of the thermal decomposition was characterized as orthorhombic BaBr2 from (I); the intermediate residue, as a mixture of orthorhombic BaCO3 and BaCl2 and cubic BaO and the final residue, as a mixture of cubic and tetragonal BaO and orthorhombic BaCl2 (II); the intermediate residue, as orthorhombic BaCO3 and as a final residue, a mixture of cubic and tetragonal BaO from (III); and the intermediate residue, as a mixture of orthorhombic BaCO3 and BaCl2 and as a final residue, a mixture of cubic and tetragonal BaO and orthorhombic BaCl2 from (IV).

Pulse treatments to extend the postharvest life of Ctenanthe setosa cut foliage

Marantaceae leaves have a contrasting color pattern and a decorative design which are interesting traits for its use as cut foliage. No postharvest research has been carried out on the potential as cut foliage for species of Ctenanthe, a member of the Marantaceae. Grey-maranta (Ctenathe setosa) is an herbaceous ornamental plant native of Brazil whose cut foliage has potential to be used as new crop product for local and international ornamental markets. The objective of this study was to evaluate pulse treatments to extend the longevity of foliage. The experiment was conducted in a complete randomized design with three replications and eight treatments: distilled water; pulsing cut petioles-ends in citric acid (pH = 2.8/1h); 2% sucrose (4h); 1% sucrose plus 200 mg L-1 citric acid (4h); 0.01% Tween® 20 (4h); 100 mg L -1 benzyladenine plus 0.01% Tween® 20 (4h); 100 mg L-1 gibberellic acid plus 0.01% Tween® 20 (4h); and maintenance of cut petiole in holding solution with commercial sodium hypochlorite (0.5 mL L-1). The senescence symptoms were mainly characterized by leaf rolling and by a decrease in the angle formed between leaf and petiole as a response to water deficit stress. Gibberellic acid or benzyladenine pulse treatments significantly extended longevity (6 days compared to control) and maintained leaves' green coloration and brightness for a longer time compared to control. However, only the benzyladenine plus Tween® 20 pulse maintained leaves in an erect form for a longer time, showing a significantly higher angle between leaf and petiole compared to control. Also, foliage pulsed with benzyladenine plus Tween® 20 showed a significant smallest loss of accumulated fresh mass percentage compared to control by the T test as to parallelism of treatments lines.

Molecular recognition of sub-micromolar inhibitors by the epinephrine-synthesizing enzyme phenylethanolamine N-methyltransferase

The crystal structures of human phenylethanolamine N-methyltransferase in complex with S-adenosyl-L-homocysteine (7, AdoHcy) and either 7-iodo-1,2,3,4-tetrahydroisoquinoline (2) or 8,9-dichloro-2,3,4,5-tetrahydro-1H-2-benzazepine (3, LY134046) were determined and compared with the structure of the enzyme complex with 7 and 7-aminosulfonyl-1,2,3,4-tetrahydroisoquinoline (1, SK&F 29661). The enzyme is able to accommodate a variety of chemically disparate functional groups on the aromatic ring of the inhibitors through adaptation of the binding pocket for this substituent and by subtle adjustments of the orientation of the inhibitors within the relatively planar binding site. In addition, the interactions formed by the amine nitrogen of all three inhibitors reinforce the hypothesis that this functional group mimics the beta-hydroxyl of norepinephrine rather than the amine. These studies provide further clues for the development of improved inhibitors for use as pharmacological probes.

Crystal structures and hydrogen-bonding in the co-crystalline adducts of 3,5-dinitrobenzoic acid with 4-aminosalicylic acid and 2-hydroxy-3-(1H-indol-3-yl)propenoic acid

The structures of the cocrystalline adducts of 3,5-dinitrobenzoic acid (3,5-DNBA) with 4-aminosalicylic acid (PASA), the 1:1 partial hydrate, C7H4N2O6 .C7H7NO3 . 2H2O, (I) and 2-hydroxy-3-(1H-indol-3-yl)propenoic acid (HIPA) and the 1:1:1 d6-dimethylsulfoxide solvate, C7H4N2O6 . C11H9NO3 . C2D6OS, (II) are reported. The crystal substructure of (I) comprises two centrosymmetric hydrogen-bonded R2/2(8) homodimers, one with 3,5-DNBA, the other with PASA, and an R2/2(8) 3,5-DNBA-PASA heterodimer. In the crystal, inter-unit amine N-H...O and water O-H...O hydrogen bonds generate a three-dimensional supramolecular structure. In (II), the asymmetric unit consists of the three constituent molecules which form an essentially planar cyclic hydrogen-bonded heterotrimer unit [graph set R2/3(17)] through carboxyl, hydroxy and amino groups. These units associate across a crystallographic inversion centre through the HIPA carboxylic acid group in an R2/2~(8) hydrogen-bonding association, giving a zero-dimensional structure lying parallel to (100). In both structures, pi--pi interactions are present [minimum ring centroid separations: 3.6471(18)A in (I) and 3.5819(10)A in (II)].

Ethyl 1-(2-cyanoethyl)-3,5-dimethyl-1H-indole-2-carboxylate

The title compound, C16H18N2O2, is an important precursor in the synthesis of 1,2,3,4-tetrahydropyrazinoindoles, which show excellent antihistamine, antihypertensive and central nervous system depressant properties. The carbethoxy group attached to C2 and the planar cyanoethyl group attached to N1 make dihedral angles of 11.0(4) and 75.0(3)degrees, respectively, with the mean plane of the indole ring, The C-C=N chain is linear with a bond angle of 179.3 (4)degrees.

Methyl 1H-1,2,3-triazole-4-carboxylate

The title compound, C4H5N3O2, features an essentially planar molecule (r.m.s. deviation for all non-H atoms = 0.013 angstrom). The crystal structure is stabilized by intermolecular N-H center dot center dot center dot O hydrogen bonds and pi-pi stacking interactions (centroid centroid distance 3.882 angstrom).

A thermal molecular migration in the solid-state - structures of isomeric 5-amino-4-(2,6-dichlorophenyl)-1-(2-nitrophenyl)-1h-1,2,3-triazole (yellow form i) and 4-(2,6-dichlorophenyl)-5-(2-nitroanilino)-2h-1,2,3-triazole (red form-ii), c14h9cl2n5o2

Yellow form (I): Mr= 350.09, monoclinic, P2Jn, Z--4, a=9.525(1), b=14.762(1), c= 11.268(1),/t, fl= 107.82 (1) o , V= 1508.3 A 3 , Din(flotation in aqueous KI)= 1.539 (2), D x= 1.541 (2) g cm -3, #(Cu Ka, 2 = 1.5418 A) = 40.58 cm -~, F(000) = 712, T= 293 K, R = 8.8% for 2054 significant refections. Red form (II): Mr= 350.09, triclinic, Pi, Z=2, a=9.796(2), b= 10.750 (2), c= 7.421 (1)A, a= 95.29 (2), fl= 0108-2701/84/111901-05501.50 70.18 (1), y = 92-.76 (2) °, V= 731.9 A 3, Din(flotation in KI) = 1.585 (3), D x = 1.588 (3) g cm -3, ~t(Cu Ka, 2 = 1.5418/~) = 40.58 cm -1, F(000) = 356, T=293 K, R = 5.8% for 1866 significant reflections. There are no unusual bond distances or angles. The triazole and two phenyl rings are planar. On the basis of packing considerations the possibility of intermolecular interactions playing a role in the reactivity of the starting material is ruled out.

NMR (1H, 13C) and MO (ab initio, CNDO/2, EHT) studies on basic and N-protonated hydrazinecarbothioamide

The conformational preferences of hydrazinecarbothioamide (HCTA, H2NNHCSNH2) in its basic and N-protonated (PHCTA, H3NNNHCSNH2) forms have been studied by 1H and 13C NMR spectroscopy and by theoretical LCAO-MO methods (ab initio, CNDO/2 and EHT). The hindered rotation around the C---N bond has been investigated by a total line shape analysis for the thioamide protons and by the three MO methods. Changes in the molecular conformation and electronic structure on protonation are briefly discussed.