南极海洋嗜冷菌Shewanella sp. NJ49的多环芳烃低温代谢分子机制研究

PAHs are toxic pollutants that exist extensively in the environment, which have increasingly influenced the environment of Antarctica . Up to the present day, most of studies have reported the successful degradation of PAHs by meophilic bacteria. Only a few study focused at cold-adapted degrading microbe in low temperature marine environment, especially fewer in civil study. Meophilic bacteria was more sensitive to low temperature. Enzymes of meophilic bacteria was not active in low temperature, whereas, Antarctica marine psychrophile grow rapidly at 0℃ or lower temperature. Research team of applicant have isolated and characterized Antarctica psychrophile bacteria for their high-degrading efficiency of utilize PAHs in low temperature environment. This study will be undertaken to further understand mechanism of PAHs low-temperature metabolism with material of Antarctic marine psychrophile bacteria Shewanella sp. NJ49 at molecular level. Plasmid genome sequences will be acquired by genomics technique and so on. By the means of bioinformatics and RT-PCR technique, PAHs metabolism pathways and key limit-speed enzyme will be characterized. Gene clusters responsible for PAHs oxidation will be recognized. Gene expression and low-temperature adoption mechanism could be understood. Based on above all, molecular mechanism of PAHs low-tmeperature metabolism will be characterized. This study would provide information for further application research of bioremediation in low temperature environment, that are important not only for Antarctic ecosystem balance but also for removing PAHs from low temperature marine environment of our country.

芳烃持久性污染物的扩散及危害日益受到关注，其影响远及南极生态系统。目前芳烃降解菌研究大都集中在常温微生物，对低温海洋微生物代谢芳烃研究较少，我国相关研究还刚起步。由于芳烃降解菌对温度敏感，常温菌在低温环境下失活，而嗜冷菌在0℃仍较快生长，课题组前期研究证实南极海洋嗜冷菌在低温环境中能高效降解芳烃。本研究拟以南极海洋嗜冷菌Shewanella sp. NJ49为对象，采用基因组学、RT-PCR和生物信息学等技术手段，获得其质粒全基因组序列，揭示其低温代谢萘的途径，明确降解基因低温表达影响和关键低温限速酶，了解低温限速酶的分子结构特征及其对南极低温环境的适应性，据此，阐明南极海洋嗜冷菌的多环芳烃低温代谢分子机制，为低温环境芳烃持久性污染物的生物修复提供理论依据，这不仅对南极脆弱系统中芳烃污染物降解具有重要的生态学意义，对我国低温海域芳烃污染物的消除也有潜在应用意义。

课题组前期研究证实南极海洋嗜冷菌在低温环境中能高效降解芳烃。本研究以南极海洋嗜冷菌Shewanella sp. NJ49为对象，采用基因组学、RT-PCR和生物信息学等技术手段，研究获得了南极低温降解菌shewanella NJ49的单加氧酶和双加氧酶基因，开展了两种加氧酶定量荧光PCR表达分析，明确降解基因低温表达影响因素；对shewanella 进行全基因组测序、拼接、组装，获得菌株的基因信息，并基于目前的基因数据库、蛋白数据库信息，对获得的NJ49全基因组进行功能注释，并根据代谢途径注释结果，分析低温降解菌的代谢过程和相关低温、耐盐和抗辐射适应机制和降解酶基因，实验结果为构建高效低温基因工程菌提供了坚实的基础数据，为低温环境芳烃持久性污染物的生物修复提供理论依据，这不仅对南极脆弱系统中芳烃污染物降解具有重要的生态学意义，对我国低温海域芳烃污染物的消除也有潜在应用意义。