Effects on growth, antioxidant enzyme activity and levels of extracellular proteins in the green alga Chlorella vulgaris exposed to crude cyanobacterial extracts and pure microcystin and cylindrospermopsin
Effects on growth, antioxidant enzyme activity and levels of extracellular proteins in the green alga Chlorella vulgaris exposed to crude cyanobacterial extracts and pure microcystin and cylindrospermopsin
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DOI：
10.1016/j.ecoenv.2013.04.019
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发表时间：
2013-08-01
影响因子：
6.8
通讯作者：
Vasconcelos, Vitor
中科院分区：
文献类型：
--
作者：
Campos, Alexandre;Araujo, Pedro;Vasconcelos, Vitor
有毒蓝藻和蓝藻毒素被认为是控制浮游植物多样性和物种丰度的重要因素，导致生态失衡和环境污染。已经进行了体外实验来解决绿藻中有毒蓝细菌的影响。在这方面，这项工作的目的是通过评估暴露于（I）蓝藻细胞提取物和（II）纯毒素微囊藻毒素-LR（MC-LR）和圆柱藻毒素（CYN）3天和7天时的培养物生长情况，比较两种蓝藻物种（椭圆形束丝藻和铜绿微囊藻）与绿藻普通小球藻的毒性。通过抗氧化标记物谷胱甘肽 S-转移酶 (GST) 和谷胱甘肽过氧化物酶 (GPx) 的活性以及暴露 7 天的培养物中表达的细胞外蛋白，还表征了绿藻对纯毒素的生化反应。卵孢 A. ovalisporum 粗提物对普通念珠菌有毒。另一方面，高达179.0μg/L的纯毒素则刺激了绿藻的生长。生长结果表明，卵孢曲霉提取物的毒性可能是由于 CYN 和蓝藻产生的其他代谢物的协同作用所致。关于绿藻抗氧化防御机制，18.4和179.0μg/L的CYN增加了GPx和GST的活性，而浓度为179.0μg/L的MC-LR抑制了酶的活性，表现出相反的作用模式。此外，在 C vulgaris 培养基中鉴定出 F-ATP 酶亚基、腺苷酸环化酶、硫酸盐 ABC 转运蛋白、推定孔蛋白、天冬氨酸转氨酶、亚甲基四氢叶酸脱氢酶和叶绿素 a 结合蛋白，表明涉及代谢物运输、光合作用和氨基酸代谢的生化过程受到蓝藻毒素的影响，并可能有助于绿藻生长的调节。 (C) 2013 Elsevier Inc. 保留所有权利。
Toxic cyanobacteria and cyanotoxins have been pointed as important players in the control of phytoplankton diversity and species abundance, causing ecological unbalances and contamination of the environment. In vitro experiments have been undertaken to address the impact of toxic cyanobacteria in green algae. In this regard the aim of this work was to compare the toxicity of two cyanobacteria species, Aphanizomenon ovalisporum and Microcystis aeruginosa, to the green alga Chlorella vulgaris by assessing culture growth when exposed for three and seven days to (I) cyanobacterial cell extracts and (II) pure toxins microcystin-LR (MC-LR) and cylindrospermopsin (CYN). The biochemical response of the green alga to pure toxins was also characterized, through the activity of the antioxidant markers glutathione S-transferase (GST) and glutathione peroxidase (GPx) and the expressed extracellular proteins in seven-day exposed cultures. A. ovalisporum crude extracts were toxic to C vulgaris. Pure toxins up to 179.0 mu g/L, on the other hand, stimulated the green alga growth. Growth results suggest that the toxicity of A. ovalisporum extracts is likely due to a synergistic action of CYN and other metabolites produced by the cyanobacterium. Regarding the green alga antioxidant defense mechanism, CYN at 18.4 and 179.0 mu g/L increased the activity of GPx and GST while MC-LR inhibited the enzymes' activity at a concentration of 179.0 mu g/L demonstrating a contrasting mode of action. Moreover the identification of F-ATPase subunit, adenylate cyclase, sulfate ABC transporter, putative porin, aspartate aminotransferase, methylene-tetrahydrofolate dehydrogenase and chlorophyll a binding proteins in the culture medium of C vulgaris indicates that biochemical processes involved in the transport of metabolites, photosynthesis and amino acid metabolism are affected by cyanobacterial toxins and may contribute to the regulation of green alga growth. (C) 2013 Elsevier Inc. All rights reserved.