甲基叔丁基醚单一及与镉复合对蚯蚓生理指标和DNA损伤影响研究

发布时间：2018-04-06 22:06

本文选题：MTBE　切入点：Cd　出处：《山东农业大学》2015年硕士论文

【摘要】：甲基叔丁基醚(MTBE)是一种新型的汽油添加剂,由于具有高辛烷值,有效提高汽油的燃烧效率,减少CO及其他有害气体的排放等特点,自20世纪80年代初开始被广泛使用。由于MTBE水溶性大,在土壤中的迁移速率高于其他汽油成分,在存储和运输过程中泄露等问题,造成的环境污染问题日益严重。镉(Cd)是土壤重金属污染中典型代表,大量研究表明Cd能影响动物神经系统,引发癌变。环境中污染物并不是单一的存在,多种污染物的联合作用成为目前环境科学领域热门研究课题之一。因此,研究MTBE单因素及与Cd复合作用对土壤生物—蚯蚓生理指标及DNA损伤影响具有重要意义。研究主要结论如下:(1)蚯蚓在MTBE的氧化胁迫作用下,能通过激活体内的抗氧化酶系(SOD、CAT和POD)的活性消除体内过量活性氧自由基。在30mg/kg和60mg/kg浓度的MTBE作用下,蚯蚓抗氧化酶系在染毒后期出现激活程度降低和抑制的趋势,说明蚯蚓的抗氧化酶防御系统受到一定程度的损伤。染毒7-14d,SOD,CAT和POD共同作用消除MTBE胁迫下产生的活性氧自由基,而染毒21-28d,SOD和CAT是消除MTBE氧化胁迫下产生的ROS的主要抗氧化酶。(2)MTBE作用下蚯蚓能够诱导激活体内的GST活性。在10mg/kg浓度的MTBE作用下,GST活性诱导激活,而30mg/kg和60mg/kg浓度条件下蚯蚓体内的GST活性出现激活——抑制的变化规律。说明MTBE对蚯蚓GST活性的影响是污染物浓度和染毒时间共同作用的结果。(3)不同浓度的MTBE均能对蚯蚓造成脂质过氧化损伤,10mg/kg和30mg/kg浓度条件下蚯蚓体内的MDA含量与染毒时间正相关,60mg/kg浓度条件下的MDA含量与染毒时间关系不明显。说明MTBE对蚯蚓脂质过氧化损伤与污染物浓度和染毒时间有关。(4)MTBE作用下对蚯蚓体腔细胞的DNA损伤的影响主要与污染物浓度有关。与对空白组对比,10mg/kg浓度的MTBE条件下,蚯蚓体腔细胞DNA损伤程度仅在染毒28d后表现出显著差异(P0.05),而30mg/kg和60mg/kg浓度条件下DNA的损伤在染毒7d表现出显著差异(P0.05)。说明MTBE浓度是造成蚯蚓体腔细胞DNA损伤的决定因素。(5)不同浓度的MTBE与Cd复合及Cd单因素作用均能对蚯蚓产生氧化胁迫。MTBE与Cd复合能降低Cd对蚯蚓的氧化胁迫能力,降低程度在染毒前期与MTBE浓度正相关,染毒后期与浓度成负相关;MTBE和Cd复合作用下,染毒7-14d,SOD、CAT和POD协同作用消除或缓解MTBE对蚯蚓造成的氧化胁迫影响,而染毒21-28d,蚯蚓主要通过诱导激活SOD和CAT的活性缓解MTBE和Cd的氧化胁迫影响。(6)在MTBE与Cd复合及Cd单因素作用下,蚯蚓能诱导体内GST活性激活,在染毒7-21d,复合作用下的GST活性激活程度大于Cd单因素作用下的活性。随着染毒时间的延续,GST对MTBE和Cd复合毒性的解毒能力下降。(7)与Cd单因素作用下的MDA含量对比,MTBE与Cd复合作用下的含量显著降低(P0.05),MTBE的存在降低了Cd对蚯蚓的脂质过氧化损伤。MTBE与Cd复合作用对蚯蚓的脂质过氧化损伤由MTBE浓度和染毒时间共同决定。(8)MTBE与Cd复合和Cd单因素作用均能造成蚯蚓体腔细胞的DNA损伤;不同浓度的MTBE与Cd复合作用下的OTM值均低于Cd单因素作用下的OTM值,MTBE与Cd复合降低了Cd对蚯蚓体腔细胞DNA的毒性。
[Abstract]:Methyl tert butyl ether (MTBE) is a new gasoline additive, due to its high octane number, effectively improve the combustion efficiency of gasoline, reducing CO and other harmful gas emissions, has been widely used since the beginning of 1980s. Due to the water soluble MTBE, the migration rate in soil is higher than other gasoline components in the storage and transportation process, leaks and other problems, the problem of environmental pollution caused by the increasingly serious. Cadmium (Cd) is a typical representative of the heavy metals in the soil, a large number of studies show that Cd can affect animal nervous system induced carcinogenesis. Pollutants and environment is not a single, combined action of multiple pollutants has become one of the most popular research topics in the field of environmental science at present. Therefore, the single factor of MTBE and Cd and the combined effect of Earthworm on soil biological injury and physiological index of DNA has important significance. The main conclusions are as follows: (1 The role of earthworm in MTBE) under oxidative stress, antioxidant enzymes through activation in vivo (SOD, CAT and POD) activity to eliminate oxygen free radical in excess activity. In MTBE 30mg/kg and 60mg/kg concentration, earthworm antioxidase activation and inhibition decreased trend in exposure late, indicating earthworm the antioxidant defense system by a certain degree of injury. In 7-14d, SOD, CAT and POD together to eliminate active oxygen free radicals produced under MTBE stress, and exposure to 21-28d, SOD and CAT are the main antioxidant enzymes to eliminate MTBE under oxidative stress. ROS (2) MTBE under the action of earthworms can induce activation in vivo the activity of GST in MTBE. Effects of 10mg/kg concentration, GST activity and GST activity induced by activation of earthworm 30mg/kg and 60mg/kg concentration under the conditions of activation -- variations of inhibition. The effect of MTBE on the GST activity of the earthworm Is the common pollutant concentration and exposure time results. (3) different concentrations of MTBE could cause lipid peroxidation of earthworms, 10mg/kg and 30mg/kg concentration under the condition of MDA content and exposure time of earthworms is related to the content of MDA 60mg/kg concentration and exposure time was not obvious. The results showed that MTBE of earthworm the lipid peroxidation and pollutant concentration and exposure time. (4) effects of DNA damage on earthworm coelomocytes under the action of MTBE is mainly related with the concentration of pollutants. Compared with the control group, the concentration of 10mg/kg under the condition of MTBE, DNA degree of injury only in the earthworm coelomic cells after 28d exposure showed significant differences (P0.05) 30mg/kg and 60mg/kg, and the concentration of DNA under the condition of the injury in 7d exposure showed significant differences (P0.05). The results showed that MTBE concentration is the deciding factor caused by earthworm coelomic cell DNA damage. (5) MTBE and Cd of different concentration Cd composite and single factor effect can lead to oxidative stress.MTBE and Cd compound can reduce the ability of oxidative stress and Cd on earthworms on earthworms, reduce the degree of positive correlation with the concentration of MTBE in the early exposure, exposure late negative correlation with concentration; compound effect of MTBE and Cd, SOD, CAT in 7-14d, and the synergistic effect of the POD elimination or alleviate the oxidative stress caused by effects of MTBE on earthworms and earthworm, at 21-28d, mainly through the influence of oxidative stress induced by activation of SOD and the activity of CAT and Cd. The relief of MTBE (6) in the MTBE and Cd composite and Cd single factor under the action of earthworms can induce GST activity in vivo activation in 7-21d exposure, composite effect the GST activation is greater than that of Cd under the action of single factor activity. With the extension of exposure time, reduced ability to detoxify GST on MTBE and Cd composite toxicity. (7) compared with the content of MDA Cd under the single factor, the content of MTBE and Cd under the combined action of Significantly decreased (P0.05), MTBE was decreased in the presence of lipid Cd on earthworm lipid oxidative damage of.MTBE and Cd compound effects on earthworm peroxidation by MTBE concentration and exposure time determined. (8) DNA MTBE and Cd Cd composite damage and single factor effect can be caused by both MTBE and coelomic cells; effect of Cd composite under different concentrations and OTM values were lower than the Cd single factor under the action of OTM, MTBE and Cd decreased the toxicity of Cd DNA compound earthworm coelomocytes.

【学位授予单位】：山东农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X503.22;X171.5

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