大气可吸入颗粒物中微生物种群动态变化及抗药功能基因组研究

Particulate matter (PM) air pollution poses a formidable public health threat to the city of Beijing and other megacities. Among the various hazards of PM pollutants, microorganisms in PM2.5 and PM10 are thought to be responsible for various allergies and for the spread of respiratory diseases. While the physical and chemical properties of PM pollutants have been extensively studied, much less is known about the inhalable microorganisms. Most existing data on airborne microbial communities using 16S or 18S rRNA gene sequencing to categorize bacteria or fungi into the family or genus levels do not provide information on their allergenic and pathogenic potentials. Based on our recently published metagenomic study (ES&T, 2014) on the microbial composition of Beijing's PM pollutants during a severe January smog event, in which we showed that with sufficient sequencing depth, airborne microbes including bacteria, archaea, fungi, and dsDNA viruses can be identified at the species level. Here we propose to apply the latest techniques in metagenomics to study the airborne microbiome at a greater scale, by analyzing the seasonal variation and differences with various regions of the world, as well as their drug resistance genes and heir potential health effects. Our proposed project may serve as an important reference for environmental scientists, health workers, and city planners.

北京等大城市大气可吸入颗粒物污染已成为社会经济发展中的重大问题。可吸入颗粒物（PM2.5和PM10）有非常复杂的化学和微生物组分，是各种过敏与呼吸道疾病的诱因。国内外虽已有许多从颗粒物物理、化学性质角度做的研究，但从微生物生态学角度对大气可吸入颗粒物中的微生物组分，其与自然环境、人类活动的关系及可能的致病、抗药机理的研究较少。本研究组最近发表了关于北京大气中微生物生态学组分的论文（ES&T, 2014），在国际上首次在种的水平上鉴别空气中极其复杂的微生物种群组分。在此基础上，本课题将利用最先进的测序技术进一步扩大研究范围和样品数量，结合大气污染条件等因素分析研究不同季节不同城市环境中大气微生物种群成分与自然环境、人类活动的关系，通过分析该微生物生态系统的抗药基因组，探索大气微生物群落可能的致病、抗药机理。本课题的研究将在公共医学、城市规划和环境治理等领域具有重要的科学和社会价值。

随着大众健康意识的提高，大气污染问题受到越来越多的关注。本课题组从微生物生态学角度对大气可吸入颗粒物（PM2.5和 PM10）中的微生物组分进行研究。利用本课题组研发的宏基因组学方法，对北京市秋冬季节106个样品的测序数据进行了分析。研究发现，大气颗粒物种的微生物以细菌和真核生物为主，PM2.5和PM10样品在群落组成方面没有显著差异。在本研究中，大气微生物的群落结构在采样时间内具有高度动态变化的特点，但却难以概括明显的时间规律。气象因素方面，研究发现温度和露点对微生物的群落结构有显著影响。通过分析样品中的抗药基因组，发现四环素和链霉素的抗性基因具有最高的丰度。本课题的研究对公共医学和环境治理等领域提供了数据基础。项目资助发表核心论文4篇，共培养2名研究生，已取得硕士学位和3名博士生，其中1名已取得博士学位。