與飲用水相關的任何潛在健康風險十分重要並值得關注。近幾年來水中的藍藻是一大隱憂。這些存在於生活用水中微生物會產生某些對人體有潛在負面影響的代謝物。根據研究報告指出，某些藍藻能夠產生神經毒性藍藻毒素 β-N-甲氨基-L-丙氨酸 (BMAA) 及其異構體 2,4-二氨基丁酸 (DAB) 和 N-2-(氨基乙基)甘氨酸 (AEG)。BMAA 與神經退行性疾病有關，例如肌萎縮側索硬化 (ALS)、阿爾茨海默病 (AD) 和 ALS-帕金森氏癡呆症 (ALS-PDC)。而AEG 和 DAB，則與引起癲癇和其他神經退行性疾病有關。因此，對藍藻在環境及工程系統中的各項壓力條件（如由過氧化氫和鹽度引起的壓力條件）產生的神經毒素有更深入的研究與了解，對於水資源的供給與管理，是至關重要的。
這項研究將探討兩種在水處理過程中藍藻常經歷的環境壓力對銅綠微囊藻（ Microcystis aeruginosa）中藍藻毒素 DAB 和 AEG 釋放的影響，這兩種環境壓力包含了水水中的過氧化氫與鹽度。此外，此研究也會檢驗上述毒素是否為細胞結構的一部分。瞭解藍藻與過氧化氫的暗反應是否會導致細胞破裂及釋放細胞毒素。而鹽度若仔細控制，也能將環境壓力控制在不會致使細胞破裂的情況。因此，這項研究探討了由過氧化氫與鹽度條件對藍藻引起的環境壓力與毒素釋放的能力。
實驗結果顯示，在暗反應條件下，過氧化氫會引起載有微囊藻細胞的樣品中 AEG 的釋放，且AEG 濃度隨著過氧化氫濃度增加而提高。對於 20 ppm 的劑量，在 6 小時的實驗中，增加的 AEG 濃度可能高達 u 至 7 ppb。而與氧化反應不同的是，鹽度增加 1% 並不會導致 AEG 的釋放。而在DAB的檢測中，過氧化氫與鹽度皆未造成DAB的顯著變化。AEG 的釋放可能不是由過氧化氫對銅綠假單胞菌細胞造成的壓力引起的。 它更有可能是由過氧化氫與細胞膜中存在的一些前體反應而引起的。後續的研究建議可探討氧化反應過程中形成的 AEG 的前體和反應機制。

It is crucial to consider any potential health risks associated with drinking water. One of the concerns over the last few decades is the presence of cyanobacteria in the water. The concern is due to the fact that these microorganisms are capable of producing metabolites, some of them potentially having negative effects when present in treated water. Some cyanobacteria have been reported to be capable of producing the neurotoxic cyanotoxin β-N-methylamino-L-alanine (BMAA) as well as its isomers 2,4-diamionobutyric acid (DAB) and N-2-(aminoethyl)glycine (AEG). BMAA has been linked to be the neurodegenerative diseases such as Amyotrophic Lateral Sclerosis (ALS), Alzheimer’s Disease (AD), and ALS-Parkinson’s Dementia Complex (ALS-PDC). For AEG and DAB, they have been linked to causing seizure and other neurodegenerative effects. Therefore, a better understanding of the production of these neurotoxins by cyanobacteria under the stress conditions in environmental and engineered systems, such as those caused by hydrogen peroxide and salinity, are important for the management of water supply.
In this study, two common environmental stresses for cyanobacteria, hydrogen peroxide in water treatment processes and salinity on environmental water, were studied for their effects on the release of cyanotoxin DAB and AEG from Microcystis aeruginosa. In addition, these toxins were also examined to see if they are part of cellular structure. Dark reactions with H2O2 will not cause cells to rupture and potentially cause increase in cyanotoxins. Salinity, if its concentration is carefully chosen, can provide stress without causing cell rupture. This study will take a look at both for their ability to cause stress and potentially cause for cyanotoxin release.
The experimental results show that hydrogen peroxide under dark reactions conditions were capable of causing the release of AEG from Microcystis cell laden samples, with AEG concentrations increased with increasing concentrations. The increased AEG concentrations could be as high as u to 7 μg-L-1 within a 6hr experiment for dose of 20 mg-L-1. Unlike oxidation, increased salinity of 10 g-L-1 did not cause the release of AEG. For both oxidation and salinity stresses, DAB was not found to change substantially. The release of AEG may not be caused by the stress to M. aeruginosa cells posed by hydrogen peroxide. It is more likely to be caused by the reaction of hydrogen peroxide with some precursors present in the cell membrane. More studies are suggested to understand the precursors and the reaction mechanism of AEG formed during the oxidation.

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