古菌细胞膜脂在古菌群落组成及其对环境响应研究中的应用

古菌作为区别于细菌和真核生物的第3种生命形式广泛分布于各种生境,与碳、氮等元素的生物地球化学循环密切相关,在整个生态系统中具有重要作用.古菌细胞膜脂作为古菌重要的生物标志物,在其群落组成和对环境变化响应的研究中具有重要指示作用.本文介绍了古菌细胞膜脂的结构特征及不同古菌类群间细胞膜脂结构差异,用以表征古菌群落的组成特征.环境中细胞膜脂丰度可反映古菌生物量,并可与基于DNA的分子生物学手段在结果准确性、分析效率和经济成本方面互补和互证.在重点介绍应用古菌细胞膜脂分析古菌群落组成和丰度的难点和重要性的基础上,结合影响古菌群落变化的环境因子如温度和pH,进一步阐述古菌与所处生境的关系,分析古菌群落演化过程及其在地球化学和地质历史事件研究方面的应用前景.

The spatial distribution of archaeal lipids in a mesoscale subtropical watershed, Southeast China

Archaea play an important role in global carbon and nitrogen cycles. Archaeal lipids, such as isoprenoid glycerol diakyl glycerol tetraethers(i GDGTs), are important biomarkers tracing change in archaeal community structure and biogeochemical processes in the natural environments. In this research, the spatial distributions of archaeal lipids in the surface sediments of the Jiulong River(JR) and the Jiulong River estuary(JRE) were examined. GDGT-0(containing zero cyclopentyl ring) and crenarchaeol were the most abundant i GDGTs in the JR and JRE. From the rivers to the estuary, the total i GDGTs, GDGT-0, crenarchaeol and archaeol concentrations showed significant spatial variation; in particular, GDGT-0 and archaeol in the river may be predominantly derived in situ from methanogens, whereas crenarchaeol in the estuary mainly derived in situ from Thaumarchaeota. We inferred that archaeal community was dominated by methanogens in the Jiulong River and by Thaumarchaeota in the Jiulong River estuary, which are consistent with change in archaeal community structure observed in other estuarine environments.

泉古菌醇与绿素在东海陆架区的分布及关系研究

【目的】研究东海陆架地区的沉积物中的泉古菌醇、绿素的分布及其相关关系。【方法】通过有机化学的方法将泉古菌醇和绿素从沉积物中萃取出来之后,利用高效液相色谱质谱连用对泉古菌醇进行定量检测,利用高效液相色谱对绿素进行定量检测。【结果】泉古菌醇和绿素在长江河口绝对量的分布在空间上呈现类似关系,并且受到陆源输入的影响较小。【结论】东海陆架区的泉古菌醇和绿素均为海洋产生,而非陆源输入,且两者呈现明显的相关关系,提示泉古菌醇具有指示历史时期东海表层初级生产力变化的潜在应用。