Studies on the Biotransformation of Arctigenin Using Electrospray Ionization Mass Spectrometry

To study the biotransformation of arctigenin, arctigenin was anaerobically incubated with Eubacterium sp. ARC-2 of human intestinal bacteria in vitro. Arctigenin formed a molecular ion [M-H](-) in negative ion mode. The arctigenin and its metabolites were investigated directly by the electrospray ionization tandem mass spectrometry ion trap and Fourier transform ion cyclotron resonance. Arctigenin was transformed to 4',4 ''-dihydroxylenterolactone by E sp. ARC-2 through 3 types of demethylation products.

Electrodepositing redox polymer on sandwich complex for the improvement of sensitivity in sandwich enzyme-linked immunoassay

Improvement of the sensitivity of electrochemical sandwich enzyme immunoassay has been achieved by electrodepositing redox polymer on screen-printed carbon electrode surface, on which the sandwich complex was formed.

粉煤灰表面形貌和组成的电子显微镜/能量色散谱、聚焦离子束分析

用超级场发射电子显微镜 (FE SEM) ,扫描电子显微镜 /能量色散谱 (SEM/EDS)和聚焦离子束测试仪(FIB)等 ,对粉煤灰进行了表面形貌和元素组成分析。FIB显示粉煤灰大多为 0.3～0.5 μm的球状微粒 ;FE SEM则显示约有 88%的粉煤灰为0.3～1 μm的球状微粒 ,表面凹凸不平 ,主要为铝、硅、铁等元素的氧化物 ,其中铝、硅、铁和氧的质量分数分别为 20.5 %、23.6%、1.4%和50.9%。

以DNA为模板构造苯胺-DNA复合物纳米线和聚苯胺纳米导线

在溶液中,以DNA为模板构造出了线性的苯胺-DNA复合物纳米线.用压缩气流将得到的复合物纳米线拉直并固定到云母基底上.用原子力显微镜(AFM)可观察到形貌规整的苯胺-DNA复合物纳米线.苯胺单体在溶液中能从各个方向上组装到DNA分子上,从而使DNA模板分子的表面包裹了一层苯胺.以苯胺-DNA复合物纳米线为前驱体通过进一步化学氧化聚合得到了以DNA为模板的聚苯胺纳米导线.

Bright electroluminescence from a new conjugated dendrimer

Photoluminescence and electroluminescence from a new conjugated dendrimer consisting of three distyrylbenzene units linked by a central nitrogen atom as core and meta-linked biphenyl units as dendrons were investigated. Bright electroluminescence was realized by using bilayer devices with blurred interface, which were fabricated by sequentially spin-coating a neat dendrimer and a dendrimer doped with 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PBD). By optimizing the concentration of PBD, the maximum brightness and EL quantum efficiency reach 4100 cd/m(2) and 0.10%, respectively.

Methanol tolerant FeTPP-Pt/C Co-catalysts for the electroreduction of oxygen

It was found for the first time that iron tetraphenylporphyrin (FeTPP)-Pt/C showed the good activity for the electroreduction of oxygen and methanol tolerant ability. Their performances were related to the heat-treatment temperature.

Conductive polyaniline poly-omega-aminoundecanoyle blending fiber

Conductive fibers were obtained by blending polyaniline with poly-omega-aminoundecanoyle in-concentrated H2SO4 Micro-fiber caused by non-compatibility between the two polymers was valuable for improving conductive property of the fibers. Abnormal effect on the crystallinity of polyaniline and poly-omega-aminoundecanoyle upon drawing stress was observed.

Acetylcholinesterase amperometric detection system based on a cobalt(II) tetraphenylporphyrin-modified electrode

An acetylcholinesterase (AChE) activity detection system was fabricated based on the electrocatalysis of cobalt(II) tetraphenylporphyrin of the electrooxidation of thiocholine chloride, which is the product of the hydrolysis of acetylthiocholine chloride by AChE. A simple modified method was used to form the base electrode. AChE was cross-linked on the base electrode by glutaraldehyde. The optimum working conditions are discussed and the characteristics of the detection system are evaluated.

不同脱乙酰度壳聚糖Mark-Houwink方程的订定

通过多步脱乙酰基反应和溶液超声波降解制备了脱乙酰度D.D在49—100％(wt),重均分子量在1.94—25.1×10~5的系列壳聚糖样品,在0.1mol/L CH_3COONa+0.2mol/L CH_3COOH溶剂中和30℃下,用光散射法首次订定出了不同D.D壳聚糖的M-H方程常数K和α值,结果如下:D.D(wt％) K×10~3(ml·g~(-)1) α69 0.104 1.1284 1.424 0.9691 6.589 0.88100 16.800 0.81导致K和α值差别的主要原因是由于壳聚糖大分子链上的胺基(—NH_2)被酸质子化后,失去了形成分子内氢键的能力,减弱了内旋转受阻程度,同时,质子化后形成的阳离子聚电解质分子链链段间以及链段与溶剂之间的相互作用增强,有效电荷密度的增加使得聚电解质溶液粘度增大。

高聚物状态方程的研究

在高分子状态方程的研究中,多数理论工作集中在高分子液态体系上,而对高分子固体状态方程的理论研究并不多,在对其压强(p),体积(V)及温度(T)之间关系的描述上,多采用经验或半经验的状态方程。 当一高分子体系处于平衡状态时,其压

XPS STUDY ON TERNARY CROSSLINKED BLOCK-COPOLYMER FROM CONDENSATION OF OLIGODIMETHYLSILOXANE WITH POLY-PARA-HYDROXYSTYRENE AND POLYARYLSULFONE OLIGOMERS

XPS has extensively been applied to the study of polymers, in which a considerably important topic is the surface phase separations in block copolymers and blends. Copolymers (or blends) will produce a phase separation if their components are in-

Molecular cloning and expression of a Toll receptor gene homologue from Zhikong Scallop, Chlamys farreri

Toll-like receptors (TLRs) are an ancient family of pattern recognition receptors, which show homology with the Drosophila Toll protein and play key roles in detecting various non-self substances and then initiating and activating immune system. In this report, the full length of the first bivalve TLR (named as CfToll-1) is presented. CfToll-1 was originally identified as an EST (expressed sequence tag) fragment from a cDNA library of Zhikong scallop (Chlamys farreri). Its complete sequence was obtained by the construction of Genome Walker library and 5' RACE (rapid amplification of cDNA end) techniques. The full length cDNA of CfToll-1 consisted of 4308 nucleotides with a polyA tail, encoding a putative protein of 1198 amino acids with a 5' UTR (untranslated region) of 211 bp and a 3'UTR of 500 bp. The predicted amino acid sequence comprised an extracellular domain with a potential signal peptide, nineteen leucine-rich repeats (LRR), two LRR-C-terminal (LRRCT) motifs, and a LRR-N-terminal (LRRNT), followed by a transmembrane segment of 20 amino acids, and a cytoplasmic region of 138 amino acids containing the Toll/IL-1R domain (TIR). The deduced amino acid sequence of CfToll-1 was homologous to Drosophila melanogaster Tolls (DmTolls) with 23-35% similarity in the full length amino acids sequence and 30-54% in the TIR domain. Phylogenetic analysis of CfToll-1 with other known TLRs revealed that CfToll-1 was closely related to DmTolls. An analysis of the tissue-specific expression of the CfToll-1 gene by Real-time PCR showed that the transcripts were constitutively expressed in tissues of haemocyte, muscle, mantle, heart, gonad and gill. The temporal expressions of CfToll-1 in the mixed primary cultured haemocytes were observed after the haemocytes were treated with 1 mu g ml(-1) and 100 ng ml(-1) lipopolysaccharide (LPS), respectively. The expression of CfToll-1 was up-regulated and increased about 2-fold at 6 h with the treatment of 1 mu g ml(-1) LPS. The expression of CfToll-1 was down-regulated with the treatment of 100 ng ml(-1) LPS. The results indicated that the expression of CfToll-1 could be regulated by LPS, and this regulation was dose-dependent. (c) 2006 Elsevier Ltd. All rights reserved.

Molecular cloning of an invertebrate goose-type lysozyme gene from Chlamys farreri, and lytic activity of the recombinant protein

Lysozyme is a widely distributed hydrolase possessing lytic activity against bacterial peptidoglycan, which enables it to protect the host against pathogenic infection. In the present study, the cDNA of an invertebrate goose-type lysozyme (designated CFLysG) was cloned from Zhikong scallop Chlamys farreri by expressed sequence tag (EST) and rapid amplification of cDNA ends (RACE) techniques. The full-length cDNA of CFLysG consisted of 829 nucleotides with a canonical polyadenylation signal sequence AATAAA and a poly(A) tail, and an open reading frame (ORF) of 603 bp encoding a polypeptide of 200 amino acid residues with a predicted molecular weight of 21.92 kDa and theoretical isoelectric point of 7.76. The high similarity of CFLysG with goose-type (g-type) lysozymes in vertebrate indicated that CFLysG should be an invertebrate counterpart of g-type lysozyme family, which suggested that the origin of g-type lysozyme preceded the emergence of urochordates and even preceded the emergence of deuterostomes. Similar to most g-type lysozymes, CFLysG possessed all conserved features critical for the fundamental structure and function of g-type lysozymes, such as three catalytic residues (Glu 82, Asp 97, Asp 108). By Northern blot analysis, mRNA transcript of CFLysG was found to be most abundantly expressed in the tissues of gills, hepatopancreas and gonad, weakly expressed in the tissues of haemocytes and mantle, while undetectable in the adductor muscle. These results suggested that CFLysG could possess combined features of both the immune and digestive adaptive lysozymes. To gain insight into the in vitro lytic activities of CFLysG, the mature peptide coding region was cloned into Pichia pastoris for heterogeneous expression. Recombinant CFLysG showed inhibitive effect on the growth of both Gram-positive and Gram-negative bacteria with more potent activities against Gram-positive bacteria, which indicated the involvement of CFLysG in the innate immunity of C. farreri. (c) 2006 Elsevier Ltd. All rights reserved.

Relative paleointensity of the geomagnetic field during the past 200 ka from the West Philippine Sea and its chronological significance

Our rock magnetic analysis of core Ph05 from the West Philippine Sea demonstrates that the core preserves a strong, stable remanent magnetization and meets the magnetic mineral criteria for relative paleointensity (RPI) analyses. The magnetic minerals in the sequence are dominated by pseudosingle-domain magnetite, and the concentration of magnetic minerals is at the same scale. Both the conventional normalizing method and the pseudo-Thellier method were used in conjunction with the examination of the rock magnetic properties and natural remanent magnetization. Susceptibility (chi), anhysteretic remnant magnetization (ARM) and saturation isothermal remnant magnetization (SIRM) were used as the natural remanent magnetization normalizer. However, coherence analysis indicated that only ARM is more suitable for paleointensity reconstruction. The age model of core is established based on oxygen isotope data and AMS(14)C data, which is consistent with the age model estimated from RPI records. The relative paleointensity data provide a continuous record of the intensity variation during the last 200 ka, which correlates well with the global references RPI stacks. Several prominent low paleointensity values are identified and are correlated to the main RPI minima in the SINT-200 record, suggesting that the sediments have recorded the real changes of geomagnetic field.