Mou Xiaozhen, Hodson Robert E, Moran Mary Ann
Department of Marine Sciences, University of Georgia, Athens, GA 30602, USA.
Environ Microbiol. 2007 Aug;9(8):2025-37. doi: 10.1111/j.1462-2920.2007.01318.x.
To characterize bacterioplankton functional assemblages that transform specific components of the coastal seawater dissolved organic carbon (DOC) pool, bromodeoxyuridine (BrdU) was used to label the bacterioplankton cells that were active following addition of single-DOC model compounds: two organic osmolytes [dimethylsulfoniopropionate (DMSP) and glycine betaine (GlyB)] and two aromatic monomers [para-hydroxybenzoic acid (pHBA) and vanillic acid (VanA)]. Bacterial populations were analysed based on in situ fluorescent immunodetection of BrdU incorporation followed by fluorescence-activated cell sorting (FACS). Sorted cells were then characterized by 16S rDNA-based analysis. Populations with high BrdU incorporation level (HI) developed within 8 h of introduction of 100 nM model compound. Terminal restriction fragment length polymorphisms (T-RFLP) analysis indicated that the HI populations in all four amendments were composed of bacteria from the same major taxa (phylum and subphylum levels), but the relative abundance of each differed. High-resolution clone libraries (each containing approximately 200 clones) showed that the HI populations in the GlyB and VanA amendments consisted of both metabolic generalists and specialists within the alpha-Proteobacteria (mainly members of the Roseobacter clade), beta-Proteobacteria and gamma-Proteobacteria (mainly members of Altermonadaceae, Chromatiaceae, Oceanospirillaceae and Pseudomonadaceae). The presence of members of OM60/241, OM185, SAR11, SAR86 and SAR116 in the HI populations indicated that members of these groups can assimilate the model DOC compounds, providing some of the first glimpses into heterotrophy by members of these poorly understood environmental clusters.
为了表征转化沿海水体溶解有机碳（DOC）库特定组分的浮游细菌功能组合，使用溴脱氧尿苷（BrdU）标记在添加单一DOC模型化合物后活跃的浮游细菌细胞：两种有机渗透物[二甲基磺基丙酸酯（DMSP）和甘氨酸甜菜碱（GlyB）]以及两种芳香单体[对羟基苯甲酸（pHBA）和香草酸（VanA）]。基于原位荧光免疫检测BrdU掺入，随后进行荧光激活细胞分选（FACS）来分析细菌群体。然后通过基于16S rDNA的分析对分选的细胞进行表征。在引入100 nM模型化合物后的8小时内出现了高BrdU掺入水平（HI）的群体。末端限制性片段长度多态性（T-RFLP）分析表明，所有四种添加物中的HI群体均由来自相同主要分类群（门和亚门水平）的细菌组成，但每种细菌的相对丰度不同。高分辨率克隆文库（每个包含约200个克隆）显示，GlyB和VanA添加物中的HI群体由α-变形菌纲（主要是玫瑰杆菌属的成员）、β-变形菌纲和γ-变形菌纲（主要是交替单胞菌科、着色菌科、海洋螺菌科和假单胞菌科的成员）中的代谢通才和专才组成。HI群体中存在OM60/241、OM185、SAR11、SAR86和SAR116的成员，表明这些群体的成员可以同化模型DOC化合物，这为这些了解甚少的环境类群的成员的异养作用提供了一些初步认识。
