本研究主要建立一套藍綠細菌RNA量測方法並將之試用於環境水樣，並以產毒的藍綠細菌，銅氯微囊藻(Microcystis aeruginosa)為研究對象，在加低劑量的氯作為氧化劑後，探討其細胞中毒素基因表現變化和毒素量的增加。RNA量測方法以反轉錄聚合酶鏈式反應(Reverse transcription-PCR, RT-PCR)測量方法為基礎，讓RNA經過萃取、去除DNA殘留片段(DNase treatment)、反轉錄過程從單股RNA轉換成雙股cDNA，再經由即時定量連鎖聚合酶定量系統(quantitative polymerase chain reaction, qPCR)配合Taqman偵測方法進行快速分析。萃取步驟經由實驗測試，更正成適用於萃取藍綠細菌的RNA，後續的去除DNA殘留片段的處理步驟也經測試確立其必要性。此方法在應用於測量環境水樣中，如金門水庫和菲律賓湖泊中，有藍綠細菌存在的水體樣本中的RNA濃度，並將之與水體樣本中的DNA和微囊藻毒素(microcystins)作相關性分析。
在探討加低劑量的氯的氧化實驗中，以流式細胞儀(flow cytometer, FCM)搭配兩種螢光染劑測試其細胞完整性和細胞活性，並以酵素結合免疫吸附分析法(ELISA)分析其細胞產生的微囊藻毒素，DNA和RNA則是以qPCR定量。RNA在計算後以相對表現量(relative expression)表示。研究結果顯示在0.2 mg/L的加氯實驗中，其毒素基因相對表現量和毒素濃度都有微幅的增加，代表著在低劑量氯給予的氧化壓力下，其細胞反應為產毒反應的可能性。相對地，在1 mg/L的加氯實驗中，細胞快速的死亡和其DNA/RNA的降解，代表著不僅是細胞迅速破裂的反應，更顯示其氧化效果可以抑制其毒素基因水平轉移的可能性。本研究可作為後續研究藍綠細菌對淨水處理流程給予氧化環境壓力之細胞變化和基因表現的參考。

Harmful algal blooms (HABs), commonly occurring in reservoirs and lakes, have been a concerning issue for operation of drinking water treatment (DWT) and human health, because of potential existence of toxins produced by algae and cyanobacteria. Among the microorganisms which are found in algal blooms, Microcystis and their associated toxins, microcystins are detected worldwide not only in the reservoirs of Taiwan but also in the lakes and reservoirs of other nations. This study investigated the cellular response of M. aeruginosa PCC7820 to the oxidative stress from common-used oxidants in DWT, Chlorine. The cell integrity, the cell activity, the relative gene expression, DNA damage, and microcystins concentration were measured. To observe the relative gene expression, RNA quantification method was modified and applied in field tests to quantify the RNA of 16S rRNA and mcyB. In field tests, cDNA concentration transformed from mRNA was found highly correlated to microcytins concentration in the samples. The results of oxidation experiments with 0.2 mg/L of chlorine showed an up-regulation of gene expression of mcyB and an increase of total microcystins within 2-3 hours, indicating the rapid response of Microcystis to the oxidative stress from chlorine. The results of increasing microcystins production may cause a potential risk if prechlorination was applied in the DWT with cyanobacteria-laden source water. For oxidation experiments of 1 mg/L of chlorine, both DNA sequence and mRNA strand of mcyB gene were damaged, which may inhibit the horizontal gene transfer of the toxic genes.

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