Chemical constituents and cytotoxic activity from the wood-decaying fungus Xylaria sp. SWUF08-37

Abstract

A new cyclic pentapeptide, pentaminolarin (1), and a new cytochalasin, xylochalasin (2), along with thirteen known compounds (3–15) were isolated from the wood-decaying fungus Xylaria sp. SWUF08-37. The absolute configurations of 1 were determined by a combination of Marfey’s method and TDDFT ECD calculation and the absolute configurations of 2 were established by TDDFT ECD calculation. Compound 12 showed moderate cytotoxicity against HeLa (IC₅₀?=?19.60?µg/mL), HT29 (IC₅₀?=?17.31?µg/mL), HCT116 (IC₅₀?=?14.28?µg/mL), MCF-7 (IC₅₀?=?15.38?µg/mL), and Vero (IC₅₀?=?24.97?µg/mL) cell lines by MTT assay. Compounds 1 and 2 showed slight cytotoxicity against all tested cancer cell lines.     

Matrix-free laser desorption/ionization of ions landed on plasma-treated metal surfaces

We report new experiments in which laser desorption/ionization time-of-flight mass spectrometry (LDI-TOF-MS) was applied to detection and characterization of gramicidin S and IgG pentapeptide (DSDPR) that were reactively landed on plasma-treated stainless steel surfaces. The distributions of [M + H](+), [M + Na](+) and [M + K](+) ion species in LDI-TOF for gramicidin S and IgG pentapeptide (DSDPR) were found to be markedly different from those in conventional MALDI-TOF spectra of the same samples. LDI-TOF mass spectra showed a strong preference for [M + K](+) adducts even in the presence of a large excess of sodium cations, or following surface treatment with trifluoroacetic acid. Alkali metal cations (K(+) and Cs(+)) can be exchanged in reactively landed peptide samples to provide the corresponding cationized peptide ions by LDI. Multiple charged trypsin cations were reactively landed into a layer of 2-(4-hydroxyphenylazo)benzoic acid and ionized by LDI. The ionization mechanisms for LDI of surface-deposited peptides are briefly discussed. Copyright (c) 2008 John Wiley & Sons, Ltd.     

Resonance scattering spectral detection of ultratrace IgG using immunonanogold-HAuCl<Subscript>4</Subscript>-NH<Subscript>2</Subscript>OH catalytic reaction

Nanogold particles of 10 nm were used to label goat anti-human IgG (GIgG) to obtain nanogold-labeled GIgG (AuGIgG). In a citrate-HCI buffer solution of pH 2.27, AuGIgG showed a strong catalytic effect on the reaction between HAuCl₄ and NH₂OH to form big gold particles that exhibited a resonance scattering (RS) peak at 796 nm. Under the chosen conditions, AuGIgG combined with IgG to form immunocomplex AuGIgG-IgG that can be removed by centrifuging at 16000 r/min. AuGIgG in the centrifuging solution also showed catalytic effect on the reaction. On those grounds, an immunonanogold catalytic RS assay for IgG was designed. With addition of IgG, the amount of AuGIgG in the centrifuging solution decreased; the RS intensity at 796 nm (I _{796 nm}) decreased linearly. The decreased intensity ΔI _{796 nm} was linear with respect to the IgG concentration in the range of 0.08–16.0 ng · mL⁻¹ with a detection limit of 0.02 ng · mL⁻¹. This assay was applied to analysis of IgG in sera with satisfactory sensitivity, selectivity and rapidity. Supported by the National Natural Science Foundation of China (Grant No. 20667001), Natural Science Foundation of Guangxi Province (Grant No. 0728213), and the Foundation of New Century Ten-Hundred-Thousand Talents of Guangxi Province     

IgG免疫纳米探针凝聚反应压电传感检测

IgG是人血清中主要抗感染的抗体, 约占成人血清免疫球蛋白总量的75%, 被视为判断健康或疾病的一个指标. 本文通过对IgG的检测, 探讨了纳米探针免疫凝聚压电传感方法的可行性.     

A New Nanogold-Labeled Immunoresonance Scattering Spectral Probe for Determination of Trace IgG

A kind of 9 nm gold nanoparticles was prepared with the trisodium citrate and used to label goat anti-human IgG to obtain an IgG immunoresonance scattering spectral probe. In pH 5.8 buffer solution and in the presence of polyethylene glycol （PEG）, the immune reaction between gold-labeled goat anti-human IgG and IgG took place, and the resonance scattering intensity at 580 nm （I580nm） was enhanced greatly. The enhanced intensity AIRS is pro- portional to the IgG concentration from 1.3 to 1.5 X 10^3 ng.mL^-1, with a detection limit of 0.78 ng.mL ^-1. This assay showed high sensitivity and good selectivity for quantitative determination of IgG in human serum, with satisfactory results.     

固体基质室温磷光免疫分析法测定人IgG

在聚酰胺膜（PM）等固体基质上,人免疫球蛋白(IgG）能与异硫氰酸荧光素（FITC）标记的羊抗人抗体（GAHAb^*）发生定量的特异性免疫反应,并保持了FITC优良的室温磷光特性,据此建立了固体基质室温磷光免疫分析（SS－RTP－IA）测定人血清中人IgG的新方法。在0.4μL（取样浓度为1.56-50ng/mL）点样体积内,人IgG的含量在0.624-20pg范围内,与室温磷光强度呈良好的线性关系。工作曲线的回归方程△Ip=31.4 46.2lg[c(Ag)/pg],n=6。相关系数r=0.999,检出限0.32pg。用于正常人血清中人IgG含量的测定,加标回收率为96％－104％,结果满意。     

类风湿因子（RF）免疫吸附剂的制备及性能研究

以球形纤维素为载体,经环氧氯丙烷活化后键联活性配基热聚人IgG,制备类风湿因子（RF）免疫吸附剂,可望用于血液灌流治疗类风湿关节炎。研究了配基的固定化条件及吸附剂的吸附性能。实验结果表明,吸附剂对IgGRF、IgMRF、IgARF的吸附率分别达到69.6%、70.3%、77.0%。