KMS XINJIANG INSTITUTE OF ECOLOGY AND GEOGRAPHY，CAS
| 微塑料-抗生素对水环境中耐药基因及微生物群落结构的影响 | |
| Alternative Title | Effects of microplastics-antibiotics on antibiotic resistance genes and microbial community structure in aquatic environment |
| 王珊珊 | |
| Subtype | 博士 |
| Thesis Advisor | 张道勇 ; 潘响亮 |
| 2020-06-30 | |
| Degree Grantor | 中国科学院大学 |
| Place of Conferral | 北京 |
| Degree Discipline | 理学博士 |
| Keyword | 微塑料 抗生素 ARGs 微生物群落结构 Microplastics Antibiotics ARGs Microbial community structure |
| Abstract | 微塑料是自然环境中普遍存在的污染物，而大量的微塑料污染及其携带的化学污染物质可能对水环境生态系统造成危害， 微塑料还可以作为细菌群落的栖息地、传播载体。抗生素作为水环境中的一类新型污染物，也会吸附到塑料表面，并在水动力作用下长距离迁移，造成抗生素、耐药菌及抗生素抗性基因（ARGs）的全球分布及对水生生物引发复合毒性。然而目前关于微塑料-抗生素复合污染物对水体中微生物群落结构的影响方面的研究较少。本论文研究了不同水域环境中微塑料对抗生素的吸附行为以及对耐药菌和 ARGs 的富集、迁移和转化行为，还通过 16S rRNA 高通量测序的方法研究了二者复合污染物对斑马鱼肠道微生物的影响作用，同时探讨了微塑料-抗生素复合污染物在食物链（丰年虾→斑马鱼）中对斑马鱼肠道微生物群落结构的影响。本论文主要的研究成果如下：（1）利用石英晶体微天平探讨了聚乙烯（PE）对抗生素的吸附作用。研究发现 PE 膜对红霉素的吸附量最多， 可达 6.5µg/cm2。另外吸附作用会随着盐度的升高而减弱， 这可能是因为钠离子或者其他阳离子也会吸附到物质表面，与污染物造成竞争吸附。（2）通过比较三种不同盐度的水体中（河水、河口水和海水体系） PE 微塑料对四种抗生素（磺胺甲基嘧啶、罗红霉素、四环素、泰乐菌素）的吸附作用，探讨在这四种抗生素的作用下，水体和 PE 上 ARGs、微生物群落变化情况。结果表明， PE 微塑料可以选择性的富集水体中的抗生素、 ARGs 和微生物。在四种抗生素的压力下， PE 微塑料与其周围水体的 ARGs 和细菌群落结构的分布具有显著性差异。相对于河口水和海水来说， PE 在河水体系中可以富集更多的ARGs。总体上， PE 微塑料上细菌的 α-多样性在河水体系中有所升高，而在河口水和海水体系中则降低，然而水体样本则表现出相反的规律。（3） 采用实时荧光定量 PCR 技术测量了底泥和 PVC 上 ARGs 的含量。 相比底泥， PVC 微塑料可以富集更多的抗生素和 ARGs。不同盐度的水体对样本中α-多样性的影响也很明显，对于 PVC 微塑料来说，在四种抗生素的作用下，多样性指数在河口水和海水中降低，而在河水体系中有所升高。 PVC 微塑料和底泥可以为微生物提供不同的生态位点，其中海水体系中二者的差异性更明显，说明 PVC 在海水中更容易形成与周围环境不同的特有生物膜结构。（4）通过比较不同浓度梯度（ng/L、 µg/L 和 mg/L）的五种抗生素（磺胺甲基嘧啶、罗红霉素、诺氟沙星、四环素和氯霉素）在微塑料（PE 和 PVC）上的吸附作用，分析了在抗生素的选择性压力下，微塑料和水体中 ARGs 的产生及变化情况以及样本的微生物多样性、群落结构组成情况。结果表明，原始水样中的 ARGs，如 SulA/folP-01、 ermF、 qnrS、 tetA、 tetC、 tetG、 tetX 和 cmlA1-01 可以附着到 PE 和 PVC 上。此外在低浓度条件下， PE 和 PVC 上的微生物多样性相对较高。除了含有许多共有细菌外，微塑料和水体中都有其特有的细菌，这些细菌的相对丰度在抗生素的作用下变化明显。其中 PVC 上的细菌在高浓度的磺胺甲基嘧啶和罗红霉素的作用下比较敏感，大多数物种的丰度急剧下降。（5）采用 16S r RNA 高通量测序方法，探讨微塑料及抗生素对斑马鱼肠道及粪便中微生物群落结构的影响。结果发现，斑马鱼可误食投喂的微塑料，大部分通过粪便的形式排出体外。粪便中共检测到 6 种不同类别的耐药基因，包括sul1、 sulA/folP-01、 ermE、 ermF、 cmlA1-01 和 cmlA1-02。 PE 微塑料的存在可显著增加粪便和肠道中微生物群落结构的差异性。（6）研究了微塑料-抗生素复合污染物在食物链（丰年虾→斑马鱼）中对斑马鱼肠道微生物群落结构的影响。结果显示，斑马鱼粪便中检测到的 ARGs 的含量明显高于丰年虾体内的，说明 ARGs 可通过食物链作用富集到高营养级的动物中，而且 PE 微塑料的存在加强了 ARGs 在高营养级动物中的含量。在 PE-氯霉素的共同作用下，斑马鱼肠道微生物的群落结构发生了较大变化，其中假单胞菌属的相对丰度随着氯霉素浓度的升高而降低，而鲸杆菌属的含量随着氯霉素浓度的升高而增加。综上所述，微塑料可作为抗生素、 ARGs 和细菌的附着载体，形成的复合污染物会进一步影响水环境和斑马鱼肠道中的微生物群落结构。本论文为环境中抗生素及 ARGs 的传播与控制提供了理论支撑，具有重要的科学与现实意义。 |
| Other Abstract | Microplastic is a ubiquitous pollutant in the natural environment, and a largeamount of plastic pollution and the toxic chemical pollutants it carries may causeharm to the water environment ecosystem. Microplastic can also be used as a habitatand a carrier for bacterial communities. As a new type of pollutant in the waterenvironment, antibiotics will also be adsorbed on the surface of plastics and migrateunder long-term hydrodynamic forces, resulting in the global distribution ofantibiotics, drug-resistant bacteria and antibiotic resistance genes (ARGs). However,there are few studies on the effects of microplastics-antibiotic composite pollutants onthe microbial community structure in water bodies. This paper studies the adsorptionbehavior of microplastics in different water environments to antibiotics, as well as theenrichment, migration and transformation behaviors of drug-resistant bacteria andARGs, and also studies the effect of the composite pollutants on zebrafish intestinalmicroorganisms. The effects of microplastics-antibiotic compound contaminants onthe zebrafish intestinal microbial community structure in the food chain (BrineShrimp → Zebrafish) were also discussed. The main results of this paper are asfollows:(1) The adsorption of antibiotics by polyethylene (PE) was discussed by usingquartz crystal microbalance. The study found that PE film has the most adsorptioncapacity for erythromycin (6.5µg / cm2). In addition, the adsorption will weaken asthe salinity increases. This may be the sodium ions or other cations will also adsorb tothe surface of the substance, causing competitive adsorption with pollutants.(2) By comparing the adsorption of four antibiotics (sulfamethazine,roxithromycin, tetracycline, tylosin) by PE microplastics in three waters with differentsalinity (river, estuary and seawater systems). We studied the changes of ARGs andmicrobial communities on water and PE. The results showed that PE can selectivelyenrich antibiotics, ARGs and microorganisms in water. Under the pressure of fourantibiotics, the distribution of ARGs and bacterial community structure between PE and their surrounding water is significantly different. Compared with estuarine waterand seawater, PE can enrich more ARGs in river water systems. In general, theα-diversity of bacteria on PE microplastics increased in river water systems, butdecreased in estuarine and seawater systems. However, water samples showed theopposite pattern.(3) Compared with the sediment, PVC microplastics can enrich more antibioticsand ARGs. The effect of water with different salinities on α-diversity in the samplewas also obvious. For PVC microplastics, under the pressure of four antibiotics, thediversity index decreased in estuary water and seawater, while increased in the riverwater system. PVC microplastics and sediments can provide different ecological sitesfor microorganisms. The difference between PVC and sediment in seawater systemswas more obvious, indicating that PVC was more likely to form a unique biofilmstructure in seawater which is different from the surrounding environment.(4) By comparing the adsorption of five antibiotics (sulfamethazine,roxithromycin, norfloxacin, tetracycline, and chloramphenicol) by microplastics (PEand PVC), we analyzed the generation and the change of ARGs in microplastics andwater, as well as the microbial diversity and community structure of the samplesunder the selective pressure of antibiotics. The results show that the ARGs in theoriginal water samples, such as SulA / folP-01, ermF, qnrS, tetA, tetC, tetG, tetX andcmlA1-01, can be attached to PE and PVC. In addition, the microbial diversity on PEand PVC is relatively high at low concentration of antibiotics. Besides the commonbacteria, microplastics and water samples have their own unique bacteria. The relativeabundance of these bacteria changes significantly under the pressure of antibiotics.Among them, the bacteria on PVC are more sensitive under the action of highconcentration of sulfamethazine and roxithromycin, and the abundance of mostspecies drops sharply.（ 5） Based on the 16S rRNA high-throughput sequencing, the effects ofmicroplastics and antibiotics on the microbial community structure in zebrafishintestines and feces were discussed. It was found that zebrafish can ingest microplastics by mistake, and most of them were excreted in the form of feces. A totalof 6 different types of ARGs were detected in feces, including sul1, sulA / folP-01,ermE, ermF, cmlA1-01 and cmlA1-02. The presence of PE microplastics cansignificantly increase the differences in the microbial community structure in fecesand intestines.(6) The effects of microplastics-antibiotic on the zebrafish intestinal microbialcommunity structure in the food chain (Brine Shrimp → Zebrafish) were studied.The results showed that the content of ARGs detected in zebrafish was significantlyhigher than that in brine shrimp, indicating that ARGs can be enriched intohigh-vegetative animals through the food chain, and the presence of PE microplasticsenhanced the ARGs at high-vegetative levels of animals. Under thePE-chloramphenicol, the zebrafish intestinal microbial community structure changedsignificantly, in which the relative abundance of Pseudomonas decreased with theincrease of chloramphenicol concentration, while Cetobacterium presented theopposite rule.In summary, microplastics can be used as carrier for antibiotics, ARGs andbacteria, and the complex pollutants will further affect the water environment and themicrobial community structure in zebrafish intestines. This thesis provides theoreticalbasis for the spread and control of antibiotics and ARGs in the environment, and hastheoretical and practical significance. |
| Subject Area | 生态学 |
| Language | 中文 |
| Document Type | 学位论文 |
| Identifier | http://ir.xjlas.org/handle/365004/15451 |
| Collection | 中国科学院新疆生态与地理研究所 研究系统 |
| Affiliation | 中国科学院新疆生态与地理研究所 |
| First Author Affilication | 中国科学院新疆生态与地理研究所 |
| Recommended Citation GB/T 7714 | 王珊珊. 微塑料-抗生素对水环境中耐药基因及微生物群落结构的影响[D]. 北京. 中国科学院大学,2020. |
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