Radniecki Tyler S, Dolan Mark E, Semprini Lewis
School of Chemical, Biological and Environmental Engineering; 101 Gleeson Hall, Oregon State University, Corvallis, Oregon 97331, USA.
Environ Sci Technol. 2008 Jun 1;42(11):4093-8. doi: 10.1021/es702623s.
Ammonia oxidizing bacteria (AOB) are inhibited by many compounds found in wastewater treatment plant (WWTP) influent, including aromatic hydrocarbons. The detection of "sentinel genes" to identify the presence of aromatic hydrocarbons could be useful to WWTP operators. In this study, the transcriptomic responses of Nitrosomonas europaea during the cometabolism of benzene to phenol and toluene to benzyl alcohol and benzaldehyde were evaluated using whole genome Affymetrix microarrays and qRT-PCR. Benzyl alcohol and benzaldehyde were found not to inhibit N. europaea. However, phenol concentrations as low as 5 microM directly inhibited ammonia oxidation. Surprisingly, there were no significant up- or down-regulation of genes in N. europaea cells exposed to 20 microM toluene, which caused 50% inhibition of ammonia oxidation. Exposing N. europaea to 40 microM benzene, which caused a similar degree of inhibition, resulted in the up-regulation of seven adjacent genes, including NE 1545 (a putative pirin protein) and NE 1546 (a putative membrane protein), that appear to be involved with fatty-acid metabolism, lipid biosynthesis, and membrane protein synthesis. qRT-PCR analysis revealed that NE 1545 and NE 1546 were significantly up-regulated upon exposure to benzene and phenol, but not upon exposure to toluene. Transmission electron microscope images revealed a shift in outer cell structure in response to benzene exposure.
氨氧化细菌（AOB）会受到污水处理厂（WWTP）进水所含的许多化合物的抑制，其中包括芳烃。检测“哨兵基因”以识别芳烃的存在，这对污水处理厂的操作人员可能会有所帮助。在本研究中，利用全基因组Affymetrix微阵列和定量逆转录聚合酶链反应（qRT-PCR）评估了欧洲亚硝化单胞菌在苯共代谢生成苯酚以及甲苯共代谢生成苯甲醇和苯甲醛过程中的转录组反应。结果发现苯甲醇和苯甲醛不会抑制欧洲亚硝化单胞菌。然而，低至5微摩尔的苯酚浓度会直接抑制氨氧化。令人惊讶的是，暴露于20微摩尔甲苯的欧洲亚硝化单胞菌细胞中的基因没有明显上调或下调，而该浓度的甲苯会导致50%的氨氧化抑制。将欧洲亚硝化单胞菌暴露于40微摩尔苯（其导致的抑制程度相似）中，会导致包括NE 1545（一种假定的匹林蛋白）和NE 1546（一种假定的膜蛋白）在内的七个相邻基因上调，这些基因似乎与脂肪酸代谢、脂质生物合成和膜蛋白合成有关。qRT-PCR分析表明，暴露于苯和苯酚时NE 1545和NE 1546会显著上调，但暴露于甲苯时则不会。透射电子显微镜图像显示，细胞外结构因暴露于苯而发生了变化。
