湖泊沉积物中类蛭弧菌与氨氧化菌群的分布及其捕食关系

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	湖泊沉积物中类蛭弧菌与氨氧化菌群的分布及其捕食关系
	梁龙
导师	梁小兵 ; 王明义
	2013
学位授予单位	中国科学院研究生院
学位授予地点	北京
学位名称	硕士
学位专业	环境工程
关键词	氨氧化细菌氨氧化古菌类蛭弧菌捕食作用百花湖
摘要	氨氧化菌（AOM）参与完成微生物硝化作用过程第一阶段，将NH4+转化为NO2-。环境中很多因素会影响AOM的数量和群落结构，进而影响硝化作用过程，微生物之间的捕食作用就是其中一个很重要的因素。本文的研究目的是研究环境中的一种捕食性细菌——类蛭弧菌（BALOs）与氨氧化菌之间的关系，研究类蛭弧菌的捕食作用对硝化作用过程是否具有影响。类蛭弧菌是一类能够专性捕食革兰氏阴性菌（G-）的原核微生物，对环境中大多数G-具有捕食作用，且对不同的G-具有不同捕食效率。氨氧化菌主要分为氨氧化细菌（AOB）和氨氧化古菌（AOA）两类，其中AOB属于革兰氏阴性细菌（G-），是BALOs的潜在捕食对象。为了研究类蛭弧菌的捕食作用是否会影响氨氧化菌的数量以及氨氧化作用的效率，本文设计了一个类蛭弧菌与氨氧化菌的共培养实验，同时测定了百花湖中不同深度沉积物中类蛭弧菌、AOA、AOB的数量，分析了类蛭弧菌和AOA、AOB及AOB与AOA的数量比之间的相关性，初步得到以下几点认识：1、类蛭弧菌与氨氧化菌的共培养实验说明类蛭弧菌在一定程度上能促进培养液中的氨氧化作用。本文测定了共培养实验中培养液的NH4+和NO2-的含量随时间的变化趋势。从测定结果可以看出类蛭弧菌造成了硝化作用过程中NO2-的积累；实验过程中测定的实验组中NH4+浓度略高于空白组，在各个时间段实验组和空白组培养液中NH4+浓度的变化量也存在一定的差异，尤其是在第5~7天和第7~9天这两个时间段（这两个时间段是实验组NO2-累积的时间段）中，空白组NH4+浓度呈增加趋势，而实验组NH4+浓度增加量低于空白组甚至呈下降趋势，这说明由于类蛭弧菌的存在，实验组中氨氧化作用得到了一定程度的加强。2、对AOB 和AOA的amoA基因定量分析结果表明，百花湖沉积物中AOB的数量随沉积物深度的增加变化不大，其拷贝数在6.10×106~3.37×107拷贝/克沉积物（湿重）之间，平均值为1.33×107 拷贝/克沉积物（湿重）；百花湖沉积物中AOA的amoA基因数量在1.74×105～2.00×106 拷贝/克沉积物（湿重）之间，平均值为7.18×105 拷贝/克沉积物；AOA的数量在百花湖沉积物中的垂直分布具有明显的分层现象，其中在0~20cm的沉积物中，AOA的数量变化不大，而在20~30cm的沉积物中，AOA的数量增加一倍以上；百花湖沉积物中AOB的数量高于AOA的数量，且它们在各层沉积物中的数量比也呈现明显的分层现象。在1~4cm的沉积物中，AOB与AOA的数量比呈明显的下降趋势，5~18cm沉积物中这个比例基本稳定在20~30左右，而19cm~30cm比例则下降并稳定在10左右。3、对类蛭弧菌的定量结果表明，类蛭弧菌在百花湖沉积物中的数量分布也具有分层现象。在1~7cm的沉积物中，类蛭弧菌的数量变化不大，其平均数量为4.08×106拷贝/克沉积物（湿重）；在8~17cm的沉积物中，类蛭弧菌的数量也变化不大，其平均值为2.04×106拷贝/克沉积物（湿重）；在18~30cm的沉积物中，类蛭弧菌的数量在1.11×106~8.82×106拷贝/克沉积物之间，变化幅度较大，其平均值为4.10×106拷贝/克沉积物（湿重）。4、对类蛭弧菌与AOA、AOB及AOB和AOA的数量比的相关性分析表明，百花湖沉积物中类蛭弧菌的数量与AOA的数量及AOB和AOA的数量比之间不存在显著的相关关系，而与AOB的数量存在较好的正相关关系（r=0.6089, F test, p=0.0006）。
其他摘要	Ammonia-oxidizing microorganisms (AOM) are a kind of microorganisms that perform the first stage of nitrification in which NH4+ was converted to NO2-．As one of the factors that influence the microbial community structure，the predation among microorganisms may change the abundance and community structure of AOM，and then influence the nitrification processes．The research aimed to know the influence of Bdellovibrio and-like organisms (BALOs) which are a kind of predatory bacteria on the AOM and the nitrification processes．Bdellovibrio and-likeorganisms are predators which can prey other G- bacteria and have different prey efficiency．AOM were divided into two clusters：ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA)．AOB were a kind of G- which is the potential prey of BALOs． For the research aim a cultivation experiment of AOM together with BALOs was designed．Abundances of BALOs，AOB and AOA in sediments of Lake Baihua were measured and the correlations between them were analyzed．The ratio of AOB and AOA was analyzed．Following are the detail results we’ve got：1．In the cultivation experiment，the concentrates of NH4+ and NO2- in different incubation time were measured．We got the results that the BALOs caused the accumulation of NO2-，the increase of NH4+ in trace amounts，and also the different variation of NH4+ in each incubation time compared to the BALOs negative group．During the incubation time of 7 and 9 days when the NO2- was accumulated，the concentration of NH4+ increased in BALOs negative group，while increased in a smaller amount or even decreased in BALOs positive group．These results indicated that BALOs promoted the ammonia process in the culture solution．2．Number of AOB amoA gene were 6.10×106~3.88×107copies/gram sediment (wet) with an average of 1.33×107 copies/gram sediment (wet) and not variational obviously with the depth in different sediment layers．In contrast，number of AOA amoA gene was between 1.74×105～2.00×106copies/gram sediment(wet)，which was averagely in 7.18×105 copies/gram sediment (wet) and had a significant difference between the shallow and deep sediments．Additionally，the ratios of AOB and AOA decreased obviously in 1~4cm sediment layers，while the ratios were stable and around 20~30 in 5~18cm sediment layers，and decereased to about 10 in 19~30cm sediment layers．3．The vertical distribution of the number of BALOs in sediments of Lake Baihua had significant layered appearance. The numbers of BALOs were not variational obviously with the depth and the average number is 4.08×106 copies/gram sediment (wet) in 1~7cm sediment layers．In 8~17cm，the numbers of BALOs were also stable，but got an average of 2.04×106 copies/gram sediment (wet)．The numbers of BALOs in 18~30cm sediment layers varied obviously and the average number is 4.10×106 copies/gram sediment (wet)．4．The correlation analysis showed that there is no correlation between abundance of BALOs and AOA or the AOB /AOA ratio．However，the correlation between abundance of BALOs and AOB is obvious with the correlation coefficient 0.6089．
学科领域	环境地球化学
语种	中文
文献类型	学位论文
条目标识符	http://ir.gyig.ac.cn/handle/352002/5840
专题	研究生_研究生_学位论文
推荐引用方式 GB/T 7714	梁龙. 湖泊沉积物中类蛭弧菌与氨氧化菌群的分布及其捕食关系[D]. 北京. 中国科学院研究生院,2013.

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