短短芽孢杆菌降解芘的细胞毒性分析  

Cytotoxicity Assay of Pyrene Biodegradation by Brevibacillus brevis

作　　者：廖丽萍[1] 尹华[2] 刘芷辰[1] 叶锦韶[1] 彭辉[3] 刘则华[2] 

机构地区：[1]暨南大学环境学院,广东省高校水土环境毒害性污染物防治与生物修复重点实验室,广东广州510632 [2]华南理工大学环境与能源学院,工业聚集区污染控制与生态修复教育部重点实验室,广东广州510062 [3]暨南大学化学系,广东广州510632

出　　处：《生态环境学报》2015年第3期501-504,共4页Ecology and Environmental Sciences

基　　金：国家自然科学基金委-广东省联合基金重点项目(U0933002);广东省自然科学基金重点项目(S2013020012808)

摘　　要：近年来国内外对芘微生物降解过程中的菌种选育、降解性能和降解产物分析等相关报道较多,但针对芘降解菌与芘的分子作用机制研究却不多见。为了探明降解菌短短芽孢杆菌(Brevibacillus brevis)与芘的分子作用机制,考察了B.brevis对质量浓度为1.0 mg·L-1的芘的生物降解,分析了在无机盐培养基中B.brevis与芘作用过程中,其细胞凋亡规律及膜电位的变化,以期从细胞毒性的角度揭示PAHs的微生物降解机理。实验结果显示芘的降解率随着处理时间的增加而呈上升趋势,B.brevis对芘的降解率在168 h达到56.5%。在芘的降解过程中,细胞出现显著的凋亡现象,细胞总凋亡率与细胞早期凋亡率均在48 h时达到峰值,之后均随时间的延长而下降,168 h时细胞早期凋亡率与总凋亡率均小于0.5%,菌体依然对芘具有降解能力。随着细胞凋亡的发生,细胞膜电位下降,即细胞膜电位发生去极化现象,说明细胞外的芘与K+共转运进入细胞内,从而有助于菌体对芘的吸收与降解。Although there have been many reports on the isolation of pyrene degrading stains, pyrene degradation characteristics and its catabolites, the information regarding molecular mechanism between degrading bacteria and pyrene is limited thus far. To explore the molecular mechanism between degrading bacteriumBrevibacillus brevis and pyrene, the biodegradation of pyrene （1.0 mg·L^-1） byB. brevis, as well as the cell apoptosis and changes of membrane potential ofB. brevis under pyrene exposure in mineral salt medium （MSM） was conducted to reveal the mechanism of pyrene biodegradation from the perspective of cytotoxicity. The experimental results showed that pyrene degradation efficiency increased with time. And the biodegradation efficiency of pyrene by B. brevis reached 56.5% after 168 h. In the degradation process, pyrene significantly induced the cell apoptosis. Both the total percentage of apoptotic cells and the percentage of apoptotic cells in the early stage reached their peak values on the 48th h, and decreased thereafter with the extension of time. The total percentage of apoptotic cells and the percentage of apoptotic cells in the early stage were all less than 5% at 168 h, which revealed thatB. brevis at this stage still had degradation capability for pyrene. Moreover, as the apoptosis occurred, cell membrane potential declined evidently, which meant that cell membrane potential was depolarized. This result implied that extracellular pyrene and K＋ co-transported into the cells, thus promoting the uptake and degradation of pyrene.

关 键 词：芘 微生物降解 细胞凋亡 细胞膜电位 

分 类 号：X171.5[环境科学与工程—环境科学]