title: Cyanobacterial blue color formation during lysis under natural conditions.
abstract: Cyanobacteria produce numerous volatile organic compounds (VOCs), such as β-cyclocitral, geosmin, and 2-methylisoborneol, which show lytic activity against cyanobacteria. Among these compounds, only β-cyclocitral causes a characteristic color change from green to blue (blue color formation) in the culture broth during the lysis process. In August 2008 and September 2010, the lysis of cyanobacteria involving blue color formation was observed at Lake Tsukui in northern Kanagawa Prefecture, Japan. We collected lake water containing the cyanobacteria and investigated the VOCs, such as β-cyclocitral, β-ionone, 1-propanol, 3-methyl-1-butanol, and 2-phenylethanol, as well as the number of cyanobacterial cells and their damage and pH changes. As a result, the following results were confirmed: the detection of several VOCs, including β-cyclocitral and its oxidation product, 2,2,6-trimethylcyclohexene-1-carboxylic acid; the identification of phycocyanin based on its visible spectrum; the lower pH (6.7 and 5.4) of the lysed samples; and characteristic morphological change in the damaged cyanobacterial cells. We also encountered the same phenomenon on 6 September 2013 in Lake Sagami in northern Kanagawa Prefecture and obtained almost the same results, such as blue color formation, decreasing pH, damaged cells, and detection of VOCs, including the oxidation products of β-cyclocitral. β-Cyclocitral derived from Microcystis has lytic activity against Microcystis itself but has stronger inhibitory activity against other cyanobacteria and algae, suggesting that the VOCs play an important role in the ecology of aquatic environments.
authors: Graduate School of Environmental and Human Science and Faculty of Pharmacy, Meijo University, Nagoya, Japan takoma@kfx.biglobe.ne.jp.
authors: Suzue
authors: S
authors: Arii
authors: Kanagawa Prefectural Institute of Public Health, Shimomachiya, Chigasaki, Kanagawa, Japan.
authors: Kiyomi
authors: K
authors: Tsuji
authors: Aichi Prefectural Institute of Public Health, Tsujimachi, Kita, Nagoya, Japan.
authors: Koji
authors: K
authors: Tomita
authors: Graduate School of Environmental and Human Science and Faculty of Pharmacy, Meijo University, Nagoya, Japan.
authors: Masateru
authors: M
authors: Hasegawa
authors: Graduate School of Environmental and Human Science and Faculty of Pharmacy, Meijo University, Nagoya, Japan Department of Plant Physiology and Development, Jagiellonian University, Krakow, Poland.
authors: Beata
authors: B
authors: Bober
authors: Graduate School of Environmental and Human Science and Faculty of Pharmacy, Meijo University, Nagoya, Japan.
authors: Ken-ichi
authors: K
authors: Harada
mesh_terms: D003116:Color; D000458:Cyanobacteria / Q000378:metabolism*; D007564:Japan; D060106:Lakes / Q000032:analysis*; D012621:Seasons; D055549:Volatile Organic Compounds / Q000032:analysis* / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000378:metabolism
chemical_list: D055549:Volatile Organic Compounds; D014874:Water Pollutants, Chemical