纳米氧化锌抗真菌机制的研究

发布时间：2018-06-02 18:52

本文选题：纳米氧化锌 + 青霉菌　；参考：《湖南工业大学》2017年硕士论文

【摘要】：纳米氧化锌优异的抗菌性能受到人们的普遍关注,但目前关于氧化锌抗菌方面的研究存在一些问题。一方面,有关氧化锌抗菌性能的研究主要集中在细菌方面,抗真菌方面的研究较少;另一方面,有关纳米氧化锌抗菌性能的产生机理还没有统一的定论;另外有研究报道显示形貌对纳米氧化锌抗菌性能具有很大的影响。针对以上情况,本文采用自制的不同形貌纳米氧化锌,通过比对其对不同真菌的抑制率大小从中筛选出具有广谱抗真菌性能的纳米氧化锌。随后在此基础上通过研究模拟日光照射和黑暗条件下纳米氧化锌抗真菌性能、模拟氧化锌溶出锌离子抗真菌性能、观察氧化锌与真菌相互作用、检测氧化锌处理前后真菌的生理生化指标以及进行真菌转录组测序五个方面分析了纳米氧化锌抗真菌的机制,为纳米氧化锌抗真菌性能及机制的研究提供理论依据和参考。主要研究内容和结论如下:(1)采用乳化法、直接沉淀法和微乳液法三种方法制备三种形貌的纳米氧化锌,通过比对其对三种真菌(青霉菌、白霉菌和黏菌)的抑制率大小从中筛选出具有广谱抗真菌性能的纳米氧化锌。结果显示:三种方法分别制备出球状、片状和花瓣状的纳米氧化锌;三种氧化锌对三种真菌均显示明显的抑制作用,其抑制率大小依次为花瓣状片状球状。成功筛选出具有广谱抗真菌性能的纳米氧化锌。(2)以花瓣状纳米氧化锌为抗真菌剂,青霉菌为实验对象,从模拟日光照射和黑暗条件下氧化锌抗青霉菌性能、模拟氧化锌溶出锌离子抗青霉菌性能、氧化锌与青霉菌相互作用观察以及青霉菌生理生化指标(SOD、CAT和MDA)检测4个方面分析纳米氧化锌抗真菌的机制。结果显示:模拟日光照射和黑暗条件下纳米氧化锌均展示出抗青霉菌效果,且两种情况下氧化锌抗青霉菌作用相当,表明光催化抗菌并不是纳米氧化锌抗菌的唯一机制;在模拟氧化锌溶出锌离子抗青霉菌性能中,当锌离子浓度大于3.571 mmol/L时才能抑制青霉菌生长,而纳米氧化锌溶出的锌离子是达不到这个浓度的,表明在本研究中锌离子溶出不是纳米氧化锌抗真菌的主要机制;扫描电镜结果显示氧化锌成功吸附在青霉菌菌丝表面,菌丝形貌发生改变有的甚至断裂;经氧化锌处理后的青霉菌胞内SOD和CAT活性明显增强,MDA含量增加。综合分析得出在本研究中纳米氧化锌主要通过直接附着于真菌表面产生氧化应激破坏真菌胞内生理活动达到抗真菌作用。(3)对氧化锌应激条件下的青霉菌(实验组)和未经氧化锌处理的青霉菌(对照组)进行转录组测序。测序共获得31 837条高质量Unigenes,注释到GO和KEGG数据库分别获得14 062个和5 006个注释基因,并从中筛选出与抑制青霉菌生长相关的基因。结果显示在实验组青霉菌中有多个与氧化应激相关的基因发生了显著上调。其次,实验组与对照组的比对分析中发现实验组中与膜的完整组成、锌离子结合功能、跨膜运输功能、氧化磷酸化功能等相关的基因的表达均发生了显著地上下调,结果表明纳米氧化锌抗青霉菌作用与这些基因有密切关系。进一步证明纳米氧化锌通过直接与青霉菌相互作用产生氧化应激抑制青霉菌的生长,溶出锌离子进入胞内促进氧化锌抗菌。另外,实验组青霉菌中其他一些基因也发生了不同程度地上下调变化,揭示它们在纳米氧化锌抗青霉菌的过程中可能发挥着重要作用,值得进一步研究。
[Abstract]:The excellent antibacterial properties of nanoscale Zinc Oxide are being paid much attention to, but there are some problems in the research on the antibacterial properties of Zinc Oxide. On the one hand, the research on the antibacterial properties of Zinc Oxide is mainly focused on the bacteria, and the anti fungal research is less. On the other hand, the mechanism of the antibacterial properties of the nanoscale Zinc Oxide is also related to the mechanism of the production of the antibacterial properties of Zinc Oxide. There is no unified conclusion, and other studies have shown that morphology has a great effect on the antibacterial properties of nanoscale Zinc Oxide. In this paper, the nano Zinc Oxide with different morphologies was used to screen out the nanoscale Zinc Oxide with broad spectrum antifungal properties by comparing its inhibition rate to different fungi. The anti fungal properties of nano Zinc Oxide under sunlight and dark conditions were simulated, the antifungal properties of Zinc Oxide dissolved in zinc ions were simulated, the interaction between Zinc Oxide and fungi was observed, the physiological and biochemical indexes of the fungi before and after the Zinc Oxide treatment and the sequencing of the fungus transcriptional group were analyzed in five aspects. The mechanism of bacteria provides theoretical basis and reference for the study of antifungal properties and mechanisms of nano Zinc Oxide. The main contents and conclusions are as follows: (1) the preparation of three kinds of nanoscale Zinc Oxide by emulsification, direct precipitation and microemulsion, by comparing the inhibition rate of three fungi (Penicillium, mildew and slime fungus) to three fungi The nanoscale Zinc Oxide with broad-spectrum antifungal properties was screened in a small way. The results showed that three methods were prepared to produce spherical, flake, and petal nanoscale Zinc Oxide respectively, and three kinds of Zinc Oxide showed significant inhibitory effect on three fungi, and the inhibition rate was in the form of petal like spheroid. The broad-spectrum antifungal activity was successfully screened. Nanoscale Zinc Oxide. (2) using petal like nano Zinc Oxide as antifungal agent, Penicillium as the experimental object, from simulated sunlight and dark conditions, the performance of anti Penicillium of Penicillium by Zinc Oxide, simulated by Zinc Oxide to dissolve the zinc ion against Penicillium, the interaction between Zinc Oxide and Penicillium, and the physiological and biochemical indexes of Penicillium (SOD, CAT and MDA). The antifungal mechanism of nanoscale Zinc Oxide was analyzed in 4 aspects. The results showed that nanoscale Zinc Oxide showed anti Penicillium effect under simulated sunlight and dark conditions, and the anti Penicillium effect of Zinc Oxide was the same in two cases. It was not the only mechanism of nano Zinc Oxide to resist bacteria. In the properties of Penicillium, the growth of Penicillium can be inhibited when the concentration of zinc ion is greater than 3.571 mmol/L, while the zinc ions dissolved by nano Zinc Oxide can not reach this concentration. It shows that in this study, the dissolution of zinc ions is not the main mechanism of the antifungal resistance of nanoscale Zinc Oxide. The results of scanning electrical microscope showed that Zinc Oxide successfully adsorbed Penicillium bacteria. On the surface of the silk, the morphology of mycelium changed and even broken; the intracellular SOD and CAT activity of Penicillium after Zinc Oxide treatment increased significantly, and the content of MDA increased. In this study, it was concluded that the nanoscale Zinc Oxide was primarily attached to the surface of the fungus to produce oxidative stress to destroy the intracellular physiological activity of fungi. (3) The transcriptional sequence of Penicillium (experimental group) and non Zinc Oxide treated Penicillium (control group) under Zinc Oxide stress was sequenced. A total of 31837 high quality Unigenes were sequenced, 14062 and 5006 annotated genes were obtained from the GO and KEGG databases, and the genes related to the inhibition of Penicillium growth were screened out and the results showed that the genes were found to be related to the growth of Penicillium. In the experimental group, several genes related to oxidative stress were significantly up-regulated in the experimental group. Secondly, in the comparison analysis between the experimental group and the control group, the whole composition of the membrane in the experimental group, the zinc ion binding function, the transmembrane transport function, the oxidative phosphorylation function and other related genes were significantly downregulated. The results showed that the effect of nanoscale Zinc Oxide against Penicillium was closely related to these genes. It was further proved that nanoscale Zinc Oxide could inhibit the growth of Penicillium by direct interaction with Penicillium, and dissolved zinc ions into the cell to promote the antibacterial activity of Zinc Oxide. In addition, the other genes of Penicillium in the experimental group also had different processes. The down-regulation of the above changes revealed that they might play an important role in the process of resistance to Penicillium in Zinc Oxide.
【学位授予单位】：湖南工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R318.08;TB383.1

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