本文關(guān)鍵詞：纖維素納米晶體對大腸桿菌生物毒性的影響研究　出處：《沈陽農(nóng)業(yè)大學》2017年碩士論文　論文類型：學位論文

  更多相關(guān)文章： 大腸桿菌 毒性 纖維素納米晶體

【摘要】：近年來,纖維素納米晶體作為一種可再生納米材料,在造紙、化妝品、汽車、電子產(chǎn)品等領(lǐng)域有著廣泛應用。纖維素納米晶體在被生產(chǎn)運用的同時,將通過各種途徑進入空氣、土壤、水體中,當纖維素納米晶體進入到環(huán)境之后是否對生物產(chǎn)生一定的毒害作用卻鮮有報道。為了探究三種纖維素納米晶體對大腸桿菌的毒性影響,本論文對細菌生長、細胞膜通透性、抗氧化酶活性、細胞形態(tài)等方面進行研究,得出以下結(jié)論。當濃度為250mg/L時,羧基化棉花纖維素納米晶體(CCCNCs)和羧基化木漿纖維素納米晶體(CWPCNCs)不能抑制大腸桿菌的生長,而羥基化棉花纖維素納米晶體(HCCNCs)能抑制大腸桿菌的生長。當濃度范圍在750mg/L-2500mg/L內(nèi)時,隨著纖維素納米晶體濃度的升高,對大腸桿菌的抑制作用增強,且同一濃度下,不同纖維素納米晶體對大腸桿菌的抑制率不同,抑制作用大小為HCCNCsCCCNCsCWPCNCs。棉花纖維素納米晶體能夠影響大腸桿菌的生長周期,縮短對數(shù)期,延長穩(wěn)定期。在本試驗濃度下,CWPCNCs對大腸桿菌的生長周期基本沒有影響。纖維素納米晶體能夠使細胞膜發(fā)生脂質(zhì)過氧化,改變細胞膜通透性,使細胞膜破損,乳酸脫氫酶、部分蛋白質(zhì)流出細胞外,影響細胞的結(jié)構(gòu)與功能,從而對大腸桿菌產(chǎn)生毒性。不同纖維素納米晶體對細胞膜的影響不同,同一濃度下,用HCCNCs處理過的大腸桿菌,其丙二醛含量、胞外乳酸脫氫酶活性最高,胞內(nèi)蛋白質(zhì)含量最低,細胞膜破損最為嚴重,CCCNCs次之,CWPCNCs處理中丙二醛含量、胞外乳酸脫氫酶活性低、胞內(nèi)蛋白質(zhì)含量最高,細胞膜破損程度最輕。纖維素納米晶體可以使超氧化歧化酶的活性、過氧化氫酶的活性先升高后降低,從而使大腸桿菌的抗氧化能力呈現(xiàn)先升高后降低的趨勢。不同纖維素納米晶體對大腸桿菌超氧化歧化酶的活性、過氧化氫酶的活性、抗氧化能力的影響不同。同一濃度下,三種纖維素納米晶體處理的大腸桿菌超氧化歧化酶的活性、抗氧化能力的大小均為C WPCNCsCCCNCsHCCNCs。通過對比三種纖維素納米晶體對大腸桿菌的抑制率、細胞膜損傷程度、抗氧化酶和抗氧化能力,可以得出對大腸桿菌的生物毒性大小為CWPCNCsCCCNCsHCCNCs,三種纖維素納米晶體對大腸桿菌的生物毒性受官能團、結(jié)構(gòu)、粒徑等因素的影響。纖維素納米晶體能夠使大腸桿菌變形,細胞壁、細胞膜破損,細菌滲透性遭到破壞,細胞部分物質(zhì)流出,染色質(zhì)、核糖體消失,細胞質(zhì)固縮并解體形成空腔,發(fā)生空泡變性。
[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.
【學位授予單位】：沈陽農(nóng)業(yè)大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：X172
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本文編號：1374604