Development of the methods for the Diatom tests utilizing DNA binding ability of frustle

我们重点研究了硅藻在杂色离子存在下与DNA结合的能力，试图设计出一种更好的硅藻法医检测方法。利用硅胶包裹的磁珠通过lambda DNA捕获硅藻，然后从磁珠中分离纯化硅藻。为了从血液中纯化硅藻，利用了硅藻胞体在杂色剂存在下与DNA的结合能力。该方法与常用的从血液中提取DNA的方法基本相同，即用蛋白水解酶K处理，用变色剂变性。在此条件下，DNA吸附到硅藻上，形成DNA/硅藻复合体。DNA/硅藻复合体简单回收乙醇沉淀，DNA用DNA裂解。我们还开发和评价了一种利用硅胶的DNA结合能力的硅藻染色方法。

We have focused on the DNA-binding abilities of the diatom frustule, which is constructed of silica, in the presence of chaotropic ions, in an attempt to devise a better forensic test for diatoms. It is proved possible to capture diatoms via lambda DNA using silica-coated magnetic beads followed by isolation and purification from the Mag beads.For purification of diatoms from the blood, DNA binding ability of diatom frustule in the presence of chaotropic agent was utilized. The procedure is basically same as commonly used method for DNA purification from the blood as Proteinase K treatment and denaturation using chaotropic agent. Under this condition, the DNA adsorbed to the diatom and formed DNA/diatom complex. DNA/diatom complex was simply recovered ethanol precipitation and then the DNA was fragmented using DNase.we also developed and evaluated a method for staining diatoms that exploits the DNA binding ability of silica.