Sherlock I R, James K J, Caudwell F B, MacKintosh C
Chemistry Department, Cork Institute of Technology, Bishopstown, Ireland.
Nat Toxins. 1997;5(6):247-54. doi: 10.1002/(sici)1522-7189(1997)5:6<247::aid-nt5>3.0.co;2-n.
Recent animal and bird deaths at several lakes in Ireland were indicative of possible cyanobacterial poisoning. Using protein phosphatase inhibition assays, microcystins (MCs) were identified in extracts of cyanobacteria from several lakes at concentrations ranging from 1.6 to 168 micrograms/g. This is the first report of MCs in Irish freshwaters. The protein phosphatase inhibition assay was used to screen fractions during HPLC purification of the MCs in cyanobacteria (Anabaena and Oscillatoria) and water samples from Corbally and Caragh Lakes. MC-LR, MC-HtyR, MC-FR, and MC-YR and 3 unidentified MCs of m/z values 1028.5, 981, 1042.7 were isolated from the Corbally sample; while the Caragh Lake sample contained largely MC-LR and MC-YR. A new microanalytical technique was developed for the confirmation of MCs which involved the derivatisation of the methyldehydroalanine group of MCs with 2-aminoethanethiol. Electrospray mass spectrometry of these products showed characteristic double-charged ions, and this novel technique was useful for differentiating MCs from co-eluting impurities in HPLC fractions of cyanobacterial extracts.
爱尔兰多个湖泊近期出现的动物和鸟类死亡事件表明可能存在蓝藻中毒现象。通过蛋白质磷酸酶抑制试验，在几个湖泊的蓝藻提取物中鉴定出微囊藻毒素（MCs），浓度范围为1.6至168微克/克。这是爱尔兰淡水中MCs的首次报告。蛋白质磷酸酶抑制试验用于在对蓝藻（鱼腥藻和颤藻）以及来自科巴利湖和卡拉赫湖的水样中的MCs进行高效液相色谱纯化过程中筛选馏分。从科巴利湖样品中分离出了MC-LR、MC-HtyR、MC-FR和MC-YR以及3种m/z值分别为1028.5、981、1042.7的未鉴定MCs；而卡拉赫湖样品主要含有MC-LR和MC-YR。开发了一种新的微量分析技术来确认MCs，该技术涉及用2-氨基乙硫醇对MCs的甲基脱氢丙氨酸基团进行衍生化。这些产物的电喷雾质谱显示出特征性的双电荷离子，并且这种新技术有助于从蓝藻提取物的高效液相色谱馏分中的共洗脱杂质中区分出MCs。
