日本血吸虫26ku谷胱甘肽S－转移酶Sj26抗原肽研究

多肽疫苗;日本血吸虫26ku谷胱甘肽S－转移酶Sj26抗原肽研究     

曼氏血吸虫谷胱甘肽S-转移酶Sm26/2的抗原肽研究

在计算机辅助下,应用Goldkey和PC-Gene程序,根据新报道的曼氏血吸虫谷胱甘肽S-转移酶Sm26/2的氨基酸序列,进行亲水性、柔韧性、可接近性、电荷分布和二级结构分析,预测出6个抗原肽,并用固相法进行了合成.经Dot-ELISA法测定,其中的2个对抗日本血吸虫免疫球蛋白多克隆抗体(抗-Sj-IgG-PcAb)显示出较好的抗原性,1个对抗血吸虫表膜单克隆抗体(A6McAb)显示出较好的抗原性,可作为抗血吸虫病合成多肽疫苗的候选肽段.     

Contribution a l'etude des composes sesquiterpeniques—IV Etude de la structure du carotol, alcool C15H26O de l'essence de Daucus Carota

The structure of carotol, the sesquiterpenoid monoethylenic tertiary alcohol C₁₅H₂₆O, extracted from the essential oil of Daucus Carota, has been determined using both chemical methods and infra-red spectroscopy.

This study shows that the decalanic formula proposed in 1948 by Sorm and Urbanek is erroneous. Carotol is in fact Δ²-3,10-dimethyl-6-isopropylbicyclo-(0,3,5)-decen-6-ol (I).     

Point-Substitution of Phenylalanine Residues of 26RFa Neuropeptide: A Structure-Activity Relationship Study

26RFa is a neuropeptide that activates the rhodopsin-like G protein-coupled receptor QRFPR/GPR103. This peptidergic system is involved in the regulation of a wide array of physiological processes including feeding behavior and glucose homeostasis. Herein, the pharmacological profile of a homogenous library of QRFPR-targeting peptide derivatives was investigated in vitro on human QRFPR-transfected cells with the aim to provide possible insights into the structural determinants of the Phe residues to govern receptor activation. Our work advocates to include in next generations of 26RFa_(20–26)-based QRFPR agonists effective substitutions for each Phe unit, i.e., replacement of the Phe²² residue by a constrained 1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid moiety, and substitution of both Phe²⁴ and Phe²⁶ by their para-chloro counterpart. Taken as a whole, this study emphasizes that optimized modifications in the C-terminal part of 26RFa are mandatory to design selective and potent peptide agonists for human QRFPR.     

应用于膜蒸馏过程的F26微孔膜的初步研究

以N-甲基吡咯酮作为溶剂 ,丙酮为溶胀剂 ,聚乙二醇 4 0 0为添加剂利用相转换法制备出偏氟乙烯 六氟丙烯共聚物 (F2 6 )的疏水微孔膜并且应用在膜蒸馏过程中 .研究了丙酮以及N 甲基吡咯酮 丙酮体系对膜参数以及结构的影响 .通过SEM观察了膜的微观结构 ,发现用N 甲基吡咯酮 丙酮体系制得的微孔膜兼具指状孔和海绵状孔结构 .无添加剂条件下制得的F2 6膜其对蒸馏水的接触角比相同条件下制备的PVDF膜大 .在用相转换法制备的F2 6和PVDF的疏水膜中 ,选择具有适当孔径结构的微孔膜用于膜蒸馏实验 ,F2 6膜的膜蒸馏系数比PVDF膜来得大 ,相同操作条件下的膜蒸馏通量也比PVDF膜高 .     

Structures of clausenin and clausenidin two new pyranocoumarins from the roots of clausena heptaphylla Wt. & Arn.

From the roots of Clausena heptaphylla, Wt. & Arn., two pyranocoumarins have been isolated. On the basis of spectral and degradative evidence they have been constituted as I and IV respectively.¹     

A monomeric bacteriochlorophyll triplet state (B) in reaction centres of Rhodobacter sphaeroides R26, studied by absorption-detected magnetic resonance

Using absorption-detected magnetic resonance, a new triplet state was observed in reaction centres of Rhodobacter sphaeroides R26 at 7 K. Its zero-field splitting parameters &|;D&|; = 220.5 × 10⁻⁴ cm⁻¹ and &;|;E&|; = 65.4 × 10⁻⁴ cm⁻¹, its spin polarization and its microwave-induced absorption spectrum indicate that it belongs to one of the accessory monomeric bacteriochlorophyll molecules and that it is populated through the same excitation path as the primary donor triplet ³P₈₇₀, via the radical pair ³[P₈₇₀⁺H⁻].     

Production of optically pure D-lactic acid by Nannochlorum sp. 26A4

Microalgae were screened from seawater for greenhouse gas CO2 fixation and D-lactic acid production by self-fermentation and tested for their growth rate, starch content, and conversion rate from starch into D-lactic acid. More than 300 strains were isolated, and some of them were found to have suitable properties for this purpose. One of the best strains, Nannochlorum sp. 26A4, which was isolated from Sakito Island, had a starch content of 40% (dry weight), and a conversion rate from consumed starch into D-lactic acid of 70% in the dark under anaerobic conditions. The produced D-lactic acid showed a high optical purity compared with the conventional one. The proposed new D-lactic acid production system using Nannochlorum sp. 26A4 should also be an effective technology for greenhouse gas CO2 fixation and/or conversion into industrial raw materials.     

Reactions of 26-iodopseudodiosgenin and 26-iodopseudodiosgenone with various nucleophiles and pharmacological activities of the products

26-Iodopseudodiosgenin (8) and 26-iodopseudodiosgenone (9) were reacted with various nucleophiles (KSCN, KOCN, NaCN, NaN(3) and various amines) to give pseudodiosgenin derivatives (4, 12, 16-20, 26) and pseudodiosgenone derivatives (5, 13, 21-25, 27), respectively. The reactions of 8 and 9 with KOCN gave the elimination products (10) and (11), respectively. The reaction of 9 with NaCN gave 5alpha,26- (14) and 5beta,26-dicyanocholestan-3-one (15). The reaction of 8 with NaN3 gave triazepine derivative (30), while that of 9 gave 26-azidopseudodiosgenone (31). Compound 31 was converted into triazepine derivative (32) by heating at 120 degrees C. The cytotoxicity of the pseudodiosgenins and pseudodiosgenones on P-gp-underexpressing HCT 116 cells and P-gp-overexpressing Hep G2 cells was examined by MTT assay. Pseudodiosgenins 2, 4, 12 and 30 showed strong cytotoxic activity (IC50 values: 2.6+/-0.3-6.7+/-1.4 microM), as did pseudodiosgenones 3, 5, 11, 13, 21-25 and 27 (IC50 values: 1.3+/-0.3-6.4+/-0.3 microM) toward HCT 116 cells. Pseudodiosgenins 12, 16 and 30 (IC50 values: 1.2+/-0.7-2.2+/-0.6 microM) and pseudodiosgenones 22, 23, 25 and 27 (IC50 values: 0.6+/-0.1-2.5+/-0.3 microM) were highly cytotoxic to Hep G2 cells. Compounds 3 and 27 showed efficient antibacterial activity (MIC: 15.6, 10.4 microg/ml) and (MIC: 7.8, 15.6 microg/ml) against Bacillus subtilis and Staphylococcus aureus, respectively.     

薤中新的甾体皂苷类化学成分

从薤(Allium chinense G. Don)的乙醇提取物中分离得到6个新甾体皂苷类化合物, 通过波谱数据及理化性质分析, 鉴定其分别为5α-cholano-22,16-内酯-3-O-β-D-吡喃葡萄糖基-(1→2)-[β-D-吡喃葡萄糖基-(1→3)]-β-D-吡喃葡萄糖基(1→4)-β-D-吡喃半乳糖苷(1)、 6-酮-5α-cholano-22,16-内酯-3-O-β-D-吡喃木糖基-(1→4)-[α-L-吡喃阿拉伯糖基-(1→6)]-β-D-吡喃葡萄糖苷(2)、 (25R)-26-O-β-D-吡喃葡萄糖基-5α-呋喃甾烷-3β,26-二醇-3-O-β-D-吡喃葡萄糖基-(1→2)-[β-D-吡喃葡萄糖基-(1→3)]-β-D-吡喃葡萄糖基(1→4)-β-D-吡喃半乳糖苷(3)、 (25R)-6-酮-26-O-β-D-吡喃葡萄糖基-5α-呋喃甾烷-3β,22α,26-三醇-3-O-α-L-吡喃木糖基-(1→4)-β-D-吡喃葡萄糖苷(4)、 (25R)-6-酮-5α-呋喃甾烷-3β,22α,24β,26-四醇-3-O-β-D-吡喃木糖基-(1→4)-[α-L-吡喃阿拉伯糖基-(1→6)]-β-D-吡喃葡萄糖苷(5)和(25R)-5α-呋甾-2α,3β,22α, 26-四醇-26-O-β-D-吡喃葡萄糖苷(6). 化合物1和2的皂苷元骨架在天然产物中首次分离得到. 选用H₂O₂诱导PC12细胞神经氧化损伤模型, 初步考察了6种新的呋甾型化合物的抗氧化活性, 实验结果表明, 化合物3对由H₂O₂诱导的细胞氧化损伤有显著的保护效果.     

Liquid-crystalline properties of chiral malolactonate monomers and their comb-shaped polymers

A series of optically pure mesogenic ester precursors, and the malolactonate monomers containing mesogenic alcohols obtained from them were prepared and polymerized to homopolymers and copolymers. The liquid-crystalline properties of the precursors, monomers and polymers were investigated by differential scanning calorimetry, polarized light microscopy and wide angle X-ray diffraction. The liquid-crystalline properties of the chiral mesogenic precursors and monomers were only slightly influenced by the chemical structure, configuration and the alkyl spacer length of the mesogenic alcohol substituent of the ester. The precursor, 1-[6-(4'-hexyloxy-4-biphenylyl)oxyhexyl] hydrogen (S)-O-mesylmalate (V-(S)-6) formed smectic E and smectic A phases on melting, while the monomer, 6-(4'-hexyloxy-4-biphenylyl)oxyhexyl (R)-malolactonate (II-(R)-6) showed only a crystal-isotropic phase transition. In contrast, the homopolymer of the latter exhibited a chiral smectic C phase. Copolymers from 2-(4'-hexyloxy-4-biphenylyl)oxyethyl (R)-malolactonate (II-(R)-2) also formed chiral smectic C phases.     

Effect of a Short Peptide with Alternating L- and D-Amino Acid on the Aggregation and Membrane Damage of hIAPP

Alpha-sheet is believed to be a significant structural component, formed in the fibrillation process of the amyloid peptide. However, the knowledge about the role of α-sheet played in the amyloidosis and toxicity is lack. In this work, we modified a short peptide derived from the core region of human islet amyloid polypetide(hIAPP, hIAPP_18-27) with an alternating D-amino acid replacement and investigated the effects of the L/D alternating peptide on the fibrillar aggregation and the membrane damage of hIAPP using NMR, ThT fluorescence assay, circular dichroism(CD), transmission electron microscopy(TEM) and leakage assay, and compared the results with those of hIAPP_18-27without D-amino acid replacement. We show that the short peptide with alternating L- and D-amino acids forms an α-sheet structure and is more potent in promoting the fibrillation of hIAPP and reducing the ability of hIAPP to disrupt the membrane composed of POPG and POPC[1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-(1'-rac-glycerol) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine] 1:4 lipids than the short peptide with all L-amino acids in a random coil structure. The higher potency of the D/L alternating peptide in these activities is attributed to its ability to induce the α-sheet-like structure in the core region of hIAPP and block the interaction of hIAPP with the membrane more effectively.     

Changes in biochemical properties of ovomucoid by radiation

Radiation effects on biochemical properties of ovomucoid, a protease inhibitor which is a typical allergenic protein of egg, were investigated. Trypsin inhibiting activity of ovomucoid decreased exponentially and the inactivation was larger in N₂ than in O₂. The antigenicity of ovomucoid measured by ELISA was decreased exponentially and the inactivation curves were almost the same as that of trypsin inhibiting activity. These results show that the oxygen protects the inactivation and destruction of antigenicity of ovomucoid while it enhances the reaction with ovalbumin. The effect of radiolytically generated radical anions; a pronounced protective action of (CNS)₂⁻ and a slight accelerate action of Br₂⁻ were the same both on decrease in trypsin inhibiting activity and antigenicity. SDS-PAGE showed that the change in protein structure was also protected by (CNS)₂⁻. These results suggest that the changes by radiation were not mainly due to the destruction of essential amino acid residues but to the conformational change.     

利用X射线衍射和拉曼光谱法对KCl和NaCl混合溶液微观结构的研究

利用X射线衍射法和拉曼光谱法系统研究了25 ℃下, 0-26%质量分数浓度范围内KCl和NaCl混合溶液的结构。通过分析X射线衍射法所得的混合溶液的差值结构函数F(Q)以及差值对分布函数G(r)发现,混合溶液组分中的K⁺的水化层半径及其水化数均大于Na⁺,从而揭示出常温下NaCl在水中的溶解度大于KCl的原因。在拉曼光谱的研究中,观察到溶液中水分子的四面体氢键受破坏程度随KCl浓度的增加和NaCl浓度的减少,先增大后减小,并结合X射线衍射法的结果,推断混合溶液中Na⁺对水溶液中氢键结构的破坏程度比K⁺严重,且加入适量的K⁺会使Na⁺由结构缔造者转变为打破结构者,对水溶液结构的破坏增强。     

5＇-Hydroxyzearalenol,a new β-resorcylic macrolide from Fusarium sp. 05ABR26

A new β-resorcylic macrolide, 5＇-hydroxyzearalenol （1）, was isolated from the culture broth of a marine-derived fungus Fusarium sp. 05ABR26. Three known compounds, zearalenone （2）, 8＇-hydroxyzearalenone （3） and zearalenol （4） were also isolated. The structure and relative stereochemistry of 1 were elucidated on the basis of spectroscopic data and single-crystal X-ray diffraction data. Compound 2 displayed potent inhibitory activity against Pyricularia oryzae with a MIC value of 6.25 μg/mL, while compound 3 was much less active; however, 1 and 4 showed no obvious activity.     

Geometry and tautomerism of sapphyrin—DFT studies

The structure and total energy have been investigated, applying the density functional theory (DFT), for idealized sapphyrin derivatives, created by replacements of meso-phenyl groups of 5,10,15,20-tetraphenylsapphyrin or β-alkyl groups of decaalkylsapphyrin with hydrogens or two methyl groups, respectively. The following species have been considered: the dication of plain sapphyrin (SapH₅²⁺) 12,13-dimethylsapphyrin (12,13-DMSapH₃), 12,13-dimethylsapphyrin dication (12,13-DMSapH₅²⁺), and the 10,15-dimethylsapphyrin dication (10,15-DMSapH₅²⁺). To address the issue of tautomerization the calculations have been carried out for the six feasible distribution patterns of NH protons among the five nitrogen centers of the planar sapphyrin P0_i (i=1–6). The B3LYP/6-31G optimized bond lengths and angles of sapphyrin or (dimethylated sapphyrin) skeletons are in satisfactory agreement with X-ray crystallographic values determined for decaalkylsapphyrin dications. The calculated total energies, using the B3LYP/6-31G**//3-21G approach demonstrate that the plain sapphyrin and 12,13-dimethylsapphyrin dications favor the planar geometry of the macrocycle. Localization of the methyl groups at the 10,15-meso positions of sapphyrin reversed the order of stability leading to the energy preference for the inverted structure. Thus, this steric factor related to the meso substitution seems to be instrumental in the C pyrrolic ring inversion. The DFT calculation also provided the relative stability frame for the complex tautomeric equilibria of SapH₃ which involve six different forms. Their relative stability decreases in the range: {25-NH, 26-N, 27-NH, 28-NH, 29-N} P0₃>({25-NH, 26-N, 27-NH, 28-N, 29-NH} P0₁>{25-NH, 26-NH, 27-N, 28-NH, 29-N} P0₅>{25-N, 26-NH, 27-NH, 28-NH, 29-N} P0₂>{25-NH, 26-N, 27-N, 28-NH, 29-NH} P0₆>{25-N, 26-N, 27-NH, 28-NH, 29-NH} P0₄. The stability order can be qualitatively related to the number and the nature of the cis NH interactions present in the sapphyrin core.     

Production of optically pure d-lactic acid by Nannochlorum sp. 26A4

Microalgae were screened from seawater for greenhouse gas CO₂ fixation and d-lactic acid production by self-fermentation and tested for their growth rate, starch content, and conversion rate from starch into d-lactic acid. More than 300 strains were isolated, and some of them were found to have suitable properties for this purpose. One of the best strains, Nannochlorum, sp. 26A4, which was isolated from Sakito Island, had a starch content of 40% (dry weight), and a conversion rate from consumed starch into d-lactic acid of 70% in the dark under anaerobic conditions. The produced d-lactic acid showed a high optical purity compared with the conventional one. The proposed new d-lactic acid production system using Nannochlorum sp. 26A4 should also be an effective technology for greenhouse gas CO₂ fixation and/or conversion into industrial raw materials.     

Conformational instability of a proximally-difunctionalized calix[4]-diquinone

We have recently described the electrochemical oxidation of 5,11,17,23-tetra-tert-butyl-25, 26-bis(diphenylphosphinoylmethoxy)-27,28-dihydroxycalix[4]arene into the corresponding diquinone 1. The solid state structure of 1 has now been determined by a single crystal X-ray diffraction study. Diquinone 1 crystallizes in the monoclinic space group with a=10.3507(12), b=25.219(4), c=20.2315(14) Å, β=101.166(8)°, V=5181.1(10) Å³, Z=4, and D_x=1.273 g cm⁻³. The calixarene skeleton adopts a partial cone conformation in which one quinone ring is anti-oriented with respect to the other three rings of the calixarene core. A variable temperature NMR study shows that 1 is dynamic in solution, each quinone unit undergoing fast oscillation about the axis that passes through the two meta carbon atoms bonded to the adjacent methylene groups. The motion of the quinone rings was confirmed by 2D NMR experiments.     

Coexistence of two different side chain packing structures in a smectic phase of liquid-crystalline side chain polymers

Ten varieties of liquid-crystalline side chain polymers, poly(cholesteryl-ω-(methacryloyloxy)alkanoates) (pChMO-n, n = 1, 2, 3, 4, 5, 7, 9, 10, 11 and 15; the carbon number of the alkyl chain), were studied by differential scanning calorimetry and small angle X-ray scattering. On and after the first cooling run from the isotropic state, these polymethacrylates gave the same smectic phase. X-ray investigations showed that pChMO-n with short spacers (n = 1-7) has a two layer (bilayer) S_A packing structure, and pChMO-n with a longer spacer (n= 15) has a single layer (monolayer) S_A packing structure. However, these two types of packing structure appear simultaneously in pChMO-n (n = 9s-11) below their phase transition temperature. To clarify the manner of the coexistence of the two different structures the smectic layer spacing and X-ray diffraction patterns were examined by small angle X-ray scattering at various temperatures.     

Structure de la rubranine, chalcone isolee de l'Aniba rosaeodora ducke

Rubranine, C₂₅H₂₆O₄ is a chalcone isolated from Aniba rosaeodora DUCKE. It has been established that its structure results from the condensation of a C-10 unit with 2,4,6-trihydroxychalcone.