Microcystin-RR（MC-RR）,a form of microcystin with two arginine moieties,is a cyanobacterial toxin that has been detected across a wide geographic range.It is a great concern globally because of its potential liver to...Microcystin-RR（MC-RR）,a form of microcystin with two arginine moieties,is a cyanobacterial toxin that has been detected across a wide geographic range.It is a great concern globally because of its potential liver toxicity.Herein,the abilities of BiVO4,Ag-BiVO4,Ag2O-BiVO4 and Ag/Ag2O-BiVO4 to photocatalytically degrade MC-RR under visible-light irradiation（λ≥420 nm） were investigated and compared.The possible degradation pathways were explored through analysis of the reaction intermediates by high-performance liquid chromatography-mass spectrometry.The results showed that the presence of Ag^0 enhanced the photocatalytic efficiency of Ag/Ag2O-BiVO4 via a synergetic effect between Ag2O and Ag^0 at the p-n heterojunction.Moreover,the presence of Ag^0 also greatly promoted the adsorption of MC-RR on the photocatalyst surface.Toxicological experiments on mice showed that the toxicity of MC-RR was significantly reduced after photocatalytic degradation.展开更多
采用HPLC-MS/MS监控反应,合成了微囊藻毒素RR的谷胱甘肽和半胱氨酸代谢物(MC-RRGSH及MC-RR-Cys)。该产物经Accu BOND C18固相萃取小柱纯化后,纯度大于95%(HPLC检测)。结果表明,合成反应的最佳时间为60 min。在SPE洗脱过程中,采用纯水淋...采用HPLC-MS/MS监控反应,合成了微囊藻毒素RR的谷胱甘肽和半胱氨酸代谢物(MC-RRGSH及MC-RR-Cys)。该产物经Accu BOND C18固相萃取小柱纯化后,纯度大于95%(HPLC检测)。结果表明,合成反应的最佳时间为60 min。在SPE洗脱过程中,采用纯水淋洗,1%甲酸-90%甲醇洗脱时,MCRR-GSH和MC-RR-Cys的平均回收率可达86.4%±1.5%和90.2%±2.8%。运用ESI-HPLC-MS/MS对以上产物进行一级及二级质谱扫描。两种产物的一级质谱电离均以[M+2H]2+为基峰,对应的质荷比(m/z)分别为673.6和580.5。以MC-RR-GSH和MC-RR-Cys一级质谱图中丰度最高的双电荷离子为母离子进行二级质谱扫描,对应的子离子对为m/z 609.0/536.9和519.4/520.8,由上述裂解碎片推断合成的产物为MC-RR-GSH和MC-RR-Cys。以合成产物为标准品,测定出太湖鲤鱼肾脏中MC-RR-GSH,MC-RR-Cys和MC-RR的含量(干重)分别为未检出,1.587 5,0.001 5μg·kg-1。本文合成的高纯度代谢产物,可作为相关研究中非商品化的标准对照品,代谢产物的质谱裂解碎片亦可为环境中微囊藻毒素MC-RR的GSH/Cys代谢途径分析提供参考。展开更多
Microcystins are a kind of cyclic hepatoxins produced by many species of cyanobacteria.Most previous work have been done on the toxic effects of microcystins on animals and plants.However,the reports about the effect ...Microcystins are a kind of cyclic hepatoxins produced by many species of cyanobacteria.Most previous work have been done on the toxic effects of microcystins on animals and plants.However,the reports about the effect of microcystins on microbial cells are very limited.In this work,the permeability of MC-RR on the cell outer membrane of Escherichia coli(E.coli) and Bacillus subtilis(B.subtilis) was discussed.The permeability effect of MC-RR on the cell outer membrane of E.coli and B.subtilis under different concentrations was demonstrated by a rapid and sustained reduction in the A675 values of lysozyme-treated cells.The decrease of the absorbance values showed a time-and dose-effect.The extravasations of protein and carbonhydrate increased with the increment of the treated-concentration of MC-RR.The results showed that MC-RR could increase the permeability of cell outer membranes of E.coli and B.subtilis.The synergistic effects of MC-RR and lysozyme on bacteria indicated that MC-RR might play an ecological role in bacteria in combination with other substances in some aquatic environments.展开更多
基金supported by the National Natural Science Foundation of China (21677086, 21407092, 21377067, 21577078)the Natural Science Foundation for Innovation Group of Hubei Province, China (2015CFA021)~~
文摘Microcystin-RR（MC-RR）,a form of microcystin with two arginine moieties,is a cyanobacterial toxin that has been detected across a wide geographic range.It is a great concern globally because of its potential liver toxicity.Herein,the abilities of BiVO4,Ag-BiVO4,Ag2O-BiVO4 and Ag/Ag2O-BiVO4 to photocatalytically degrade MC-RR under visible-light irradiation（λ≥420 nm） were investigated and compared.The possible degradation pathways were explored through analysis of the reaction intermediates by high-performance liquid chromatography-mass spectrometry.The results showed that the presence of Ag^0 enhanced the photocatalytic efficiency of Ag/Ag2O-BiVO4 via a synergetic effect between Ag2O and Ag^0 at the p-n heterojunction.Moreover,the presence of Ag^0 also greatly promoted the adsorption of MC-RR on the photocatalyst surface.Toxicological experiments on mice showed that the toxicity of MC-RR was significantly reduced after photocatalytic degradation.
基金supported by the Knowledge Innovation Project of the Chinese Academy of Sciences (KZCX2-YW-Q07-04)the Foundation of Key Laboratory of Marine Spill Oil Identification and Damage Assessment Technology, SOA (200713)Open Research Fund Program of Shandong Key Laboratory for Eco-Environmental Science of Yellow River Delta, Binzhou China (2007KFJJ04)
文摘Microcystins are a kind of cyclic hepatoxins produced by many species of cyanobacteria.Most previous work have been done on the toxic effects of microcystins on animals and plants.However,the reports about the effect of microcystins on microbial cells are very limited.In this work,the permeability of MC-RR on the cell outer membrane of Escherichia coli(E.coli) and Bacillus subtilis(B.subtilis) was discussed.The permeability effect of MC-RR on the cell outer membrane of E.coli and B.subtilis under different concentrations was demonstrated by a rapid and sustained reduction in the A675 values of lysozyme-treated cells.The decrease of the absorbance values showed a time-and dose-effect.The extravasations of protein and carbonhydrate increased with the increment of the treated-concentration of MC-RR.The results showed that MC-RR could increase the permeability of cell outer membranes of E.coli and B.subtilis.The synergistic effects of MC-RR and lysozyme on bacteria indicated that MC-RR might play an ecological role in bacteria in combination with other substances in some aquatic environments.
