Characterization of cell viability in Phaeocystis globosa cultures exposed to marine algicidal bacteria
Characterization of cell viability in Phaeocystis globosa cultures exposed to marine algicidal bacteria
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DOI：
10.1007/s12257-014-0437-2
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发表时间：
2015-02-01
影响因子：
3.2
通讯作者：
Yu, Qiming
中科院分区：
文献类型：
--
作者：
Hu, Xiaoli;Yin, Pinghe;Yu, Qiming
球形棕囊藻水华近年来在我国南方沿海地区频繁发生，造成了巨大的经济损失。研究了从珠海藻华中分离的菌株Y1和Y4的培养液对球形假单胞菌生理特性和细胞活力的影响。结果表明，Y1和Y4菌株培养液对球囊藻细胞产生的活性氧（ROS）水平明显升高，表明球囊藻细胞受到了氧化损伤。过量的活性氧导致丙二醛（MDA）含量增加，超氧化物歧化酶（SOD）和过氧化氢酶（CAT）活性升高。蛋白质含量的下降表明菌株Y1和Y4培养液抑制细胞生长。处理96 h后色素含量下降，说明氧化胁迫破坏了色素的合成。此外，流式细胞术结合碘化丙啶染色和叶绿素自发荧光用于研究细胞活力。结果表明，随着暴露时间的延长，叶绿素荧光强度和细胞完整性逐渐降低，表明菌株Y1和Y4培养液可改变细胞膜透性，导致这些光合色素的损失。通过培养形态、生化反应和16S rDNA同源性分析，将分离菌株鉴定为芽孢杆菌（Bacillus sp.）。总的来说，这些发现表明，由芽孢杆菌引起的氧化应激可能破坏色素合成和细胞膜完整性，并最终导致藻细胞裂解。
The bloom of Phaeocystis globosa has occurred frequently in the southern coastal areas of China in recent years, which has led to substantial economic losses. This study investigated the effects of culture broth of strains Y1 and Y4 isolated from algal blooms in Zhuhai, China on physiological characteristics and cell viability of P. globosa. The increase in the levels of reactive oxygen species (ROS) in P. globosa cells exposed to strains Y1 and Y4 culture broth were detected, indicating that the algal cells suffered from oxidative damage. The surplus ROS induced the increase of malondialdehyde (MDA) contents and the activities of antioxidant enzymes, including superoxide dismutase (SOD) and catalase (CAT). The decrease in protein content indicated that strains Y1 and Y4 culture broth inhibited cell growth. The contents of pigments decreased after 96 h treatment, indicated that oxidative stress destroyed pigment synthesis. Furthermore, flow cytometry coupled with the propidium iodide stain and chlorophyll auto-fluorescence was used to investigate cell viability. Results showed that chlorophyll fluorescence intensities and cell integrity decreased with time of exposure, which demonstrated that strains Y1 and Y4 culture broth could change membrane permeability and resulted in the loss of these photosynthetic pigments. The isolated strains were identified as Bacillus sp. by culture morphology, biochemical reactions, and homology research based on 16S rDNA. Overall, these findings suggested that oxidative stress caused from Bacillus sp. potentially destroyed pigment synthesis and cell membrane integrity, and ultimately led to the lysis of the algal cells.