Fumonisin mycotoxins in human hair

This study shows for the first time the accumulation of fumonisin mycotoxins in human hair of population clusters exposed to contaminated maize, and thus the feasibility of human hair analysis for the assessment of past fumonisin exposure. Composite hair samples were obtained from the Bizana, Butterworth and Centane districts within the Transkei region of the Eastern Cape Province of South Africa. Following methanol extraction and strong anion exchange clean up, the fumonisins FB₁, FB₂ and FB₃ were detected using high performance liquid chromatography coupled to electrospray ionization-mass spectrometry (HPLC-ESI-MS). Hair from Centane and Butterworth showed mean levels of FB₁ of 26.7 and 23.5 μg kg^-1 hair, respectively. FB₂ was only detected in hair from Centane and in one sampling point in Butterworth, with mean levels of 6.5 and 5.7 μg kg^-1 hair, respectively. Hair samples from Bizana, on the other hand, were found to contain higher levels of FB 1 (mean 33.0 μg kg^-1 hair) and FB 2 (mean 11.1 μg kg^-1 hair). No samples contained more than trace levels of FB 3 . Recoveries from spiked hair samples using this method ranged from 81% to 101%, demonstrating the applicability of hair analysis in assessing human exposure to fumonisin mycotoxins.     

Au(III)-complexes of the alanyl-containing peptides glycylalanine and glycylalanylalanine - Synthesis, spectroscopic and structural characterization

As part of an investigation on the coordination ability of peptides, the dipeptide glycylalanine (H-Gly-Ala-OH), tripeptide glycylalanylalanine (H-Gly-Ala-Ala-OH) and their Au(III)-complexes have been characterized structurally. The quantum chemical calculations and linear-dichroic infrared (IR-LD) spectroscopy predict structures of the compound studied, which are compared with a single crystal X-ray diffraction of H-Gly-Ala-OH. The coordination processes with Au(III) are supported by data for ¹H NMR, ESI-MS, HPLC-MS-MS, TGV and DSC methods. The [Au(Gly-Ala)H₋₁Cl] and [Au(Gly-Ala-Ala)H₋₂] · 2H₂O complexes are formed via -NH₂, N⁻amide/s and groups of the peptides. One Cl⁻ ion is attached to the metal center as terminal ligand in the first complex. In both cases a near to square-planar geometry of the chromophors AuN₂OCl and AuN₃O is yielded.     

肉类腐败性假单胞菌群体感应信号分子的研究

【目的】研究两株假单胞菌的标准菌株荧光假单胞菌(Pseudomonas fluorescens)和铜绿假单胞菌(Pseudomonas aeruginosa)在纯培养条件下所释放的AHLs类信号分子种类、量和变化规律。【方法】利用乙酸乙酯等有机溶剂萃取菌种纯培养液的AHLs类信号分子, 检测手段利用HPLC-MS-MS。【结果】荧光假单胞菌释放信号分子的种类为: C4-HSL、C6-HSL、C8-HSL、3-oxo-C10-HSL、3-oxo-C12-HSL、3-oxo-C14-HSL。铜绿假单胞菌释放信号分子的种类为: C4-HSL、C6-HSL、C8-HSL、C10-SL、C12-HSL、C14-HSL、3-oxo-C8-HSL、3-oxo-C10-HSL、3-oxo-C12-HSL、3-oxo-C14-HSL。【结论】两株菌所释放各类信号分子的量均随时间变化, 当菌落数达到109?1010时信号分子的量达到峰值, 两株菌所释放各类信号分子含量差异较大。     

Fumonisin mycotoxins in human hair

This study shows for the first time the accumulation of fumonisin mycotoxins in human hair of population clusters exposed to contaminated maize, and thus the feasibility of human hair analysis for the assessment of past fumonisin exposure. Composite hair samples were obtained from the Bizana, Butterworth and Centane districts within the Transkei region of the Eastern Cape Province of South Africa. Following methanol extraction and strong anion exchange clean up, the fumonisins FB₁, FB₂ and FB₃ were detected using high performance liquid chromatography coupled to electrospray ionization-mass spectrometry (HPLC-ESI-MS). Hair from Centane and Butterworth showed mean levels of FB₁ of 26.7 and 23.5 μg kg^?1 hair, respectively. FB₂ was only detected in hair from Centane and in one sampling point in Butterworth, with mean levels of 6.5 and 5.7 μg kg^?1 hair, respectively. Hair samples from Bizana, on the other hand, were found to contain higher levels of FB 1 (mean 33.0 μg kg^?1 hair) and FB 2 (mean 11.1 μg kg^?1 hair). No samples contained more than trace levels of FB 3 . Recoveries from spiked hair samples using this method ranged from 81% to 101%, demonstrating the applicability of hair analysis in assessing human exposure to fumonisin mycotoxins.     

Spectroscopic,theoretical and structural characterization of hydrogensquarates of <Emphasis Type="SmallCaps">l</Emphasis>-threonyl-<Emphasis Type="SmallCaps">l</Emphasis>-serine and <Emphasis Type="SmallCaps">l</Emphasis>-serine

Summary. Hydrogensquarates of dipeptide l-threonyl-l-serine (H-Thr-Ser-OH) and l-serine (HSq × Ser) have been synthesized, isolated and spectroscopic characterized by solid-state linear-polarized IR-spectroscopy, ¹H- and ¹³C-NMR, ESI-MS and HPLC with tandem masspectrometry (MS-MS) methods. The structures of the salts and neutral dipeptide have been predicted theoretically by ab initio calculations. In the case of H-Thr-Ser-OH the theoretical data are supported by IR-LD ones. The hydrogensquarates consist in positive charged dipeptide or amino acid moiety and negative hydrogensquarate anion (HSq) stabilizing by strong intermolecular hydrogen bonds. The data about the l-serine hydrogensquarate are compared with known crystallographic data thus indicating a good correlation between the theoretical predicted structures and experimentally obtained by single crystal X-ray diffraction.