微囊藻毒素和生物浮床对鱼类肠道微生物的影响

发布时间：2018-05-06 12:38

本文选题：肠道微生物 + 微囊藻毒素　；参考：《华中农业大学》2017年硕士论文

【摘要】：随着水产养殖集约化的发展,水体的富营养化越来越严重,蓝藻水华频发。蓝藻水华的发生通常伴随着藻毒素的产生,对鱼类的生存和人类的安全造成了严重威胁。生物浮床因其环保实用,被广泛应用于降低水体富营养化水平,控制蓝藻水华的发生。而上述过程中鱼类肠道微生物是如何变化的,对机体起到了什么作用目前还不清楚。本研究以3月龄的性成熟斑马鱼为实验材料,对其进行为期30 d的MC-LR的体外暴露,处理浓度分别为0、1、5、20μg/L,通过对暴露后斑马鱼肠道微生物16S rRNA基因测序,并测定其对MC-LR的吸收富集,超氧化物歧化酶(SOD),过氧化氢酶(CAT)和乳酸脱氢酶(LDH)活性、有机阴离子转运多肽Oatp2b1的表达,而后作相关性分析,评价了肠道微生物在其中发挥的作用。同时,通过PCR-DGGE技术评价了三种植物浮床作对草鱼肠道微生物和水体微生物的影响。具体结果如下:在用0、1、5、20μg/L的MC-LR处理30天后,斑马肠道微生物α和β多样性没有产生显著性差异,表明存在一个核心菌群,其由Fusobacteria,Actinobacteria,Alphaproteobacteria,Betaproteobacteria,Gammaproteobacteria等组成。然而,db-RDA分析显示高剂量的MC-LR改变了高丰度微生物群的特征。肠道吸收MC-LR具有剂量依赖效应。Oatp2b1表达随着MC-LR剂量的增加而增加,SOD、CAT、LDH的活性在低剂量下显著增加,而在较高剂量下则下降。使用线性判别分析效应(LEfSe)和斯皮尔曼相关性检验进一步分析这些参数。鉴定的表型包括放线菌,乳杆菌和一些条件性致病菌。MC-LR暴露增加了致病菌的致病风险,但肠道中的益生菌会通过竞争来抑制这种趋势。浮床实验表明,不同植物根系细菌组成中没有显著差异,生物浮床对池塘水的微生物群落的丰度和优势菌群都没有显著影响。草鱼肠道中的优势微生物从气单胞菌Aeromonas jandaei变为类芽孢杆菌Paenibacillus sp.,证明生物浮床能够调节肠道微生物群落结构。
[Abstract]:With the development of intensive aquaculture, eutrophication of water is becoming more and more serious, and cyanobacteria Shui Hua frequently occurs. The occurrence of cyanobacteria Shui Hua is usually accompanied by the production of algal toxins, which poses a serious threat to the survival of fish and the safety of human beings. Biological floating bed is widely used to reduce eutrophication level and control the occurrence of cyanobacteria Shui Hua because of its environmental protection and practicality. It is not clear how the intestinal microbes change during the process, and what role they play in the organism. In this study, adult zebrafish (3 months old) were exposed to MC-LR for 30 days in vitro. The concentration of rRNA was 20 渭 g / L, respectively. The 16s rRNA gene of intestinal microorganism of zebrafish was sequenced, and the absorption and enrichment of MC-LR were determined. The activities of superoxide dismutase (SOD), catalase (catalase) and lactate dehydrogenase (LDH) and the expression of organic anion transport polypeptide (Oatp2b1) were studied. At the same time, the effects of three kinds of plant floating bed on intestinal microorganism and microorganism in water of grass carp were evaluated by PCR-DGGE technique. The results were as follows: after 30 days of treatment with 20 渭 g / L MC-LR, there was no significant difference between 伪 and 尾 diversity of intestinal microbes in zebra, indicating the existence of a core flora composed of Fusobacteria actinobacteriae Alphaproteobacteria Alpha-proteobacteriae Beta proteobacteria Gammaobacteria and so on. However, Db-RDA analysis showed that high dose of MC-LR changed the characteristics of high abundance microbial community. Intestinal absorption of MC-LR was dose-dependent. The expression of Oatp2b1 increased with the increase of MC-LR dose, and increased significantly at low dose, but decreased at higher dose. Linear discriminant analysis (LDA) and Spelman correlation test were used to further analyze these parameters. The identified phenotypes include actinomycetes lactobacillus and some conditioned pathogens. MC-LR exposure increases the risk of pathogenicity but the intestinal probiotics inhibit this trend through competition. The floating bed experiment showed that there was no significant difference in the composition of root bacteria among different plants, but the biological floating bed had no significant effect on the abundance and dominant flora of microbial community in pond water. The dominant microorganism in the intestine of grass carp changed from Aeromonas jandaei to Paenibacillus sp., which proved that the floating bed could regulate the structure of intestinal microbial community.
【学位授予单位】：华中农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X503.225;S917.4

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