温榆河中硝化和反硝化基因的Real-time PCR定量

以温榆河为研究对象,采用real-time PCR研究了温榆河不同断面水样和沉积物样品中TB(总细菌)、硝化和反硝化(nosZ和narG)基因数量的变化. 水样中TB基因数量在丰水期为1.05×109~7.38×1011 copies/L,枯水期为1.06×109~2.69×1012 copies/L；氨氧化细菌(AOB)基因数量在丰水期和枯水期分别为nd(未检出)~4.11×108和nd~1.15×109 copies/L. nosZ和narG基因数量在丰水期分别为nd~2.37×108和3.61×108~1.13×1010 copies/L,枯水期分别为2.0×106~3.04×109和nd~1.39×1010copies/L. 枯水期沉积物样品中TB基因数量为1.35×109~7.32×1010 copies/g,nosZ基因数量为nd~1.06×107 copies/g,narG基因数量为1.99×107~1.02×108 copies/g. 枯水期TB基因数量略高于丰水期,枯水期水样中ρ(NH₄+-N)较高导致其AOB基因数量要远高于丰水期,nosZ和narG基因数量并没有明显的水期变化. 相关分析表明,沉积物样品中微生物基因数量与水样中微生物基因数量不相关,而是水质变化长期作用的结果. 冗余度分析表明,丰水期和枯水期水样中影响微生物基因数量的主要环境因子不同,丰水期微生物基因数量是温度、ρ(COD_Cr)、ρ(NH₄+-N)、ρ(NO₂--N)、ρ(NO₃--N)等共同作用的结果,而温度和ρ(COD_Cr)对枯水期微生物基因数量影响显著. 

Quantitative Analysis of Nitrifier and Denitrifier in Water and Sediment of the Wenyu River Using Real-time PCR

To examine temporal and spatial changes of bacterial communities in the Wenyu River at Beijing, China, water and sediment samples were collected in wet and dry seasons from eleven sites. Quantification of total bacteria (TB), ammonia-oxidizing bacteria (AOB) and denitrifer genes (nosZandnarG) were performed by real-time PCR. The copy numbers of the total bacteria 16S rRNA fragment were in the range of 1.05×109-7.38×1011 copies/L in the wet season and 1.06×109-2.69×1012 copies/L in the dry season respectively. The AOB copy numbers in the wet and the dry season were nd-4.11×108 and nd-1.15×109 copies/L respectively. The copy numbers of nosZandnarGgenes were nd-2.37×108 and 3.61×108-1.13×1010 copies/L in the wet season, while they were 2.0×106-3.04×109 and nd-1.39×1010 copies/L in dry season respectively. For sediments collected in the dry season, the copy numbers of TB, nosZand narGgenes were 1.35×109-7.32×1010, nd-1.06×107, and 1.99×107-1.02×108 copies/g. The TB copy numbers in the dry season were slightly higher than those in the wet season, while the AOB copy numbers were much higher in the dry season than in the wet season due to high concentration of ammonia nitrogen. Pearson correlation analysis showed no significant relationship between the bacteria numbers in the water and in the sediment. Redundancy discrimination analysis (RDA) showed that the predominant factors influencing the bacteria numbers in the wet and in the dry seasons were different. The bacteria number in the wet season was influenced by all the factors while temperature and ρ(COD_Cr) were the main factors affecting the bacteria number in the dry season.