纤维素纳米晶体对大肠杆菌生物毒性的影响研究

发布时间：2018-01-03 16:08

  本文关键词：纤维素纳米晶体对大肠杆菌生物毒性的影响研究　出处：《沈阳农业大学》2017年硕士论文　论文类型：学位论文

  更多相关文章： 大肠杆菌 毒性 纤维素纳米晶体

【摘要】：近年来,纤维素纳米晶体作为一种可再生纳米材料,在造纸、化妆品、汽车、电子产品等领域有着广泛应用。纤维素纳米晶体在被生产运用的同时,将通过各种途径进入空气、土壤、水体中,当纤维素纳米晶体进入到环境之后是否对生物产生一定的毒害作用却鲜有报道。为了探究三种纤维素纳米晶体对大肠杆菌的毒性影响,本论文对细菌生长、细胞膜通透性、抗氧化酶活性、细胞形态等方面进行研究,得出以下结论。当浓度为250mg/L时,羧基化棉花纤维素纳米晶体(CCCNCs)和羧基化木浆纤维素纳米晶体(CWPCNCs)不能抑制大肠杆菌的生长,而羟基化棉花纤维素纳米晶体(HCCNCs)能抑制大肠杆菌的生长。当浓度范围在750mg/L-2500mg/L内时,随着纤维素纳米晶体浓度的升高,对大肠杆菌的抑制作用增强,且同一浓度下,不同纤维素纳米晶体对大肠杆菌的抑制率不同,抑制作用大小为HCCNCsCCCNCsCWPCNCs。棉花纤维素纳米晶体能够影响大肠杆菌的生长周期,缩短对数期,延长稳定期。在本试验浓度下,CWPCNCs对大肠杆菌的生长周期基本没有影响。纤维素纳米晶体能够使细胞膜发生脂质过氧化,改变细胞膜通透性,使细胞膜破损,乳酸脱氢酶、部分蛋白质流出细胞外,影响细胞的结构与功能,从而对大肠杆菌产生毒性。不同纤维素纳米晶体对细胞膜的影响不同,同一浓度下,用HCCNCs处理过的大肠杆菌,其丙二醛含量、胞外乳酸脱氢酶活性最高,胞内蛋白质含量最低,细胞膜破损最为严重,CCCNCs次之,CWPCNCs处理中丙二醛含量、胞外乳酸脱氢酶活性低、胞内蛋白质含量最高,细胞膜破损程度最轻。纤维素纳米晶体可以使超氧化歧化酶的活性、过氧化氢酶的活性先升高后降低,从而使大肠杆菌的抗氧化能力呈现先升高后降低的趋势。不同纤维素纳米晶体对大肠杆菌超氧化歧化酶的活性、过氧化氢酶的活性、抗氧化能力的影响不同。同一浓度下,三种纤维素纳米晶体处理的大肠杆菌超氧化歧化酶的活性、抗氧化能力的大小均为C WPCNCsCCCNCsHCCNCs。通过对比三种纤维素纳米晶体对大肠杆菌的抑制率、细胞膜损伤程度、抗氧化酶和抗氧化能力,可以得出对大肠杆菌的生物毒性大小为CWPCNCsCCCNCsHCCNCs,三种纤维素纳米晶体对大肠杆菌的生物毒性受官能团、结构、粒径等因素的影响。纤维素纳米晶体能够使大肠杆菌变形,细胞壁、细胞膜破损,细菌渗透性遭到破坏,细胞部分物质流出,染色质、核糖体消失,细胞质固缩并解体形成空腔,发生空泡变性。
[Abstract]:In recent years, cellulose nanocrystalline, as a renewable nano-material, has been widely used in the fields of papermaking, cosmetics, automobile, electronic products, etc. Cellulose nanocrystalline has been produced and used at the same time. It will enter the air, soil, and water in various ways. When cellulose nanocrystals enter into the environment, it is rarely reported whether or not they have a certain toxic effect on organisms. In order to explore the toxic effects of three cellulose nanocrystals on Escherichia coli, the growth of bacteria was studied in this paper. Cell membrane permeability, antioxidant enzyme activity and cell morphology were studied, and the following conclusions were obtained: when the concentration was 250 mg / L. Carboxylated cotton cellulose nanocrystalline (CCCNCs) and carboxylated wood pulp cellulose nanocrystalline (CWPCNCs) could not inhibit the growth of Escherichia coli. The hydroxylated cotton cellulose nanocrystalline (HCCNCs) inhibited the growth of Escherichia coli when the concentration was in the range of 750 mg / L ~ (-250) mg 路L ~ (-1) 路L ~ (-1) 路L ~ (-1). With the increase of the concentration of cellulose nanocrystals, the inhibition of Escherichia coli was enhanced, and at the same concentration, the inhibition rate of different cellulose nanocrystals to Escherichia coli was different. The inhibition was HCCNCsCCCNCsCWPCNCs.The cotton cellulose nanocrystalline could affect the growth cycle of E. coli, shorten the logarithmic period and prolong the stable period. CWPCNCs has no effect on the growth cycle of Escherichia coli. Cellulose nanocrystalline can make membrane lipid peroxidation change membrane permeability damage cell membrane lactate dehydrogenase. Some proteins flow out of the cells, affecting the structure and function of the cells, thus producing toxicity to Escherichia coli. Different cellulose nanocrystals have different effects on cell membrane, at the same concentration. The malondialdehyde (MDA) content, extracellular lactate dehydrogenase activity and intracellular protein content were the highest in E. coli treated with HCCNCs, followed by cell membrane damage. The malondialdehyde (MDA) content, extracellular lactate dehydrogenase activity, intracellular protein content and cell membrane damage were the lowest in CWPCNCs treatment. Cellulose nanocrystalline could make the activity of superoxide dismutase (SOD). The activity of catalase increased first and then decreased, so that the antioxidant ability of Escherichia coli increased first and then decreased. The activity of different cellulose nanocrystals to superoxide dismutase of Escherichia coli was increased first and then decreased. The activity of catalase and antioxidant ability were different. At the same concentration, the superoxide dismutase activity of Escherichia coli treated with three kinds of cellulose nanocrystals was different. The antioxidative ability was C WPCNCsCCCNCsHCCNCs.Through comparing the inhibition rate of three kinds of cellulose nanocrystals on Escherichia coli and the degree of cell membrane damage. Antioxidant enzymes and antioxidant ability can be obtained to the biological toxicity of Escherichia coli to the size of CWPCNCsCCCNCsHCCNCs. The biotoxicity of three kinds of cellulose nanocrystals to Escherichia coli is affected by functional groups, structure, particle size and other factors. Cellulose nanocrystals can deform Escherichia coli, damage cell wall and cell membrane. The permeability of bacteria was destroyed, part of the cell substance flowed out, chromatin and ribosome disappeared, the cytoplasm was pyknosis and disintegrated to form cavity, and vacuolar degeneration occurred.
【学位授予单位】：沈阳农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X172
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本文编号：1374604