Growth, toxin production, active oxygen species and catalase activity of Microcystis aeruginosa (Cyanophyceae) exposed to temperature stress

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• 作者：Leda Giannuzzi^a ; ^b ; Bernd Krock^c ; Melina Celeste Crettaz Minaglia^a ; ^b ; Lorena Rosso^a ; Christian Houghton^d ; Daniela Sedan^a ; ^b ; Gabriela Malanga^b ; ^e ; Mariela Espinosa^f ; Darí ; o Andrinolo^a ; ^b ; Marcelo Hernando^d ; ^{mhernando@cnea.gov.ar" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Catalase ; Chlorophyll ; Microcystin variants ; ROS
• 刊名：Comparative Biochemistry and Physiology, Part C
• 出版年：2016
• 出版时间：November 2016
• 年：2016
• 卷：189
• 期：Complete
• 页码：22-30
• 全文大小：679 K

文摘

Microcystis are known for their potential ability to synthesize toxins, mainly microcystins (MCs). In order to evaluate the effects of temperature on chlorophyll a (Chl a), growth, physiological responses and toxin production of a native Microcystis aeruginosa, we exposed the cells to low (23 °C) and high (29 °C) temperature in addition to a 26 °C control treatment. Exponential growth rate was significantly higher at 29 °C compared to 23 °C and control, reaching 0.43, 0.32 and 0.33 day⁻¹ respectively. In addition, there was a delay of the start of exponential growth at 23 °C. However, the intracellular concentration of Chl a decreased significantly due to temperature change. A significant increase in intracellular ROS was observed in coincidence with the activation of enzymatic antioxidant catalase (CAT) during the first two days of exposure to 23° and 29 °C in comparison to the control experiment, decreasing thereafter to nearly initial values. Five MCs were determined by LC-MS/MS analysis. In the experiments, the highest MC concentration, 205 fg [Leu¹] MC-LR.cell^− 1 expressed as MC-LR equivalent was measured in the beginning of the experiment and subsequently declined to 160 fg.cell^− 1 on day 2 and 70 fg.cell^− 1 on day 4 in cells exposed to 29 °C. The same trend was observed for all other MCs except for the least abundant MC-LR which showed a continuous increase during exposure time. Our results suggest a high ability of M. aeruginosa to perceive ROS and to rapidly initiate antioxidant defenses with a differential response on MC production.