Graduate School of Environmental and Human Science and Faculty of Pharmacy, Meijo University, Tempaku, Nagoya 468-8503, Japan.
J Chem Ecol. 2009 Nov;35(11):1295-301. doi: 10.1007/s10886-009-9706-5. Epub 2009 Nov 20.
Volatile compounds, such as beta-cyclocitral, geosmin, and 2-methylisoborneol, from cyanobacteria showed a lytic activity against cyanobacteria. Particularly, beta-cyclocitral caused an interesting color change in the culture broth from green to blue during the lysis process. In the present study, the lytic behavior of various cyanobacteria with beta-cyclocitral was investigated, and a mechanism for the blue color formation was developed. beta-Cyclocitral lysed both the laboratory strains of any genera and bloom samples including many species of cyanobacteria, and caused the characteristic color change from green to blue. beta-Cyclocitral provided a characteristic behavior, such that the absorption maxima of chlorophyll-a and beta-carotene disappeared, but that of phycocyanin still remained after 12 h, which indicated that beta-cyclocitral decomposed chlorophyll-a and beta-carotene rapidly, so that the inherent colors from the tolerant water-soluble pigments became observable in the cultured broth. This phenomenon was confirmed by another experiment using Phormidium (NIES-611), which showed a pink color derived from phycoerythrin. beta-Cyclocitral was more easily oxidized when compared with similar aldehyde compounds, so that the pH of the solution quickly decreased to 4.5. An oxidation product of beta-cyclocitral in water solution was isolated and identified as 2,6,6-trimethylcyclohexene-1-carboxylic acid. This study provides support that beta-cyclocitral derived from cyanobacteria plays an important role in the lysis of cyanobacteria and participates in the blue color formation under natural conditions.
蓝藻产生的挥发性化合物，如β-环柠檬醛、土臭素和 2-甲基异莰醇，对蓝藻具有裂解活性。特别是，β-环柠檬醛在裂解过程中使培养液从绿色变为蓝色，引起了有趣的颜色变化。在本研究中，研究了各种蓝藻与β-环柠檬醛的裂解行为，并提出了蓝色形成的机制。β-环柠檬醛裂解了实验室培养的任何属的菌株和包括许多种蓝藻的水华样本，并导致了从绿色到蓝色的特征颜色变化。β-环柠檬醛提供了一种特征行为，即叶绿素-a 和β-胡萝卜素的吸收最大值消失，但藻蓝蛋白仍然存在 12 小时后，这表明β-环柠檬醛迅速分解叶绿素-a 和β-胡萝卜素，使耐受的水溶性色素的固有颜色在培养液中变得可见。这一现象通过使用 Phormidium (NIES-611) 的另一个实验得到了证实，该实验显示了源自藻红蛋白的粉红色。β-环柠檬醛比类似的醛化合物更容易氧化，因此溶液的 pH 值迅速下降到 4.5。在水溶液中分离并鉴定出β-环柠檬醛的氧化产物为 2,6,6-三甲基环己烯-1-羧酸。本研究支持了蓝藻产生的β-环柠檬醛在蓝藻裂解中起着重要作用，并在自然条件下参与蓝色形成的观点。
