Ziemer C J, Sharp R, Stern M D, Cotta M A, Whitehead T R, Stahl D A
Department of Animal Science, University of Minnesota, St Paul 55108, USA.
Environ Microbiol. 2000 Dec;2(6):632-43. doi: 10.1046/j.1462-2920.2000.00146.x.
A model rumen system, dual-flow continuous culture fermenters, was evaluated by two comparative criteria in two experiments using ribosomal (r)RNA-targeted DNA probes to compare key microbial groups in samples. The initial experiment measured temporal changes in population structure during adaptation of ruminal microbial populations in fermenters over 240 h. The fermenter inoculum contained 34.9% Bacteria, 60.1% Eukarya and 6.8% Archaea measured as a fraction of total small subunit (SSU) rRNA quantified using a universal probe. The cellulolytic bacterial genus Fibrobacter comprised 9.5% of total SSU rRNA in the inoculum. After 240 h of fermenter operation, the average abundance was 80.9% Bacteria, 6.1% Eukarya, 5.1% Archaea and Fibrobacter genus accounted for 6.6% of the total SSU rRNA. Divergence between ruminal and fermenter population structure was evaluated in the second experiment and samples were classified as ruminal, inoculum or fermenter (96, 120, 144 and 168 h of fermenter operation). Fermenter samples had higher relative abundances of Bacteria (84.5%) and Archaea (2.1%) and lower relative abundances of Eukarya (1.8%) than ruminal samples (average 48.0% Bacteria, 1.3% Archaea and 61.5% Eukarya). The relative abundance of Fibrobacter was similar in all samples, averaging 2.5%. The ruminal and fermenter samples had similar proportions of F. succinogenes and F. succinogenes subgroup 3 (as a percentage of Fibrobacter SSU rRNA). Fibrobacter succinogenes subgroup 1 and F. intestinalis proportions of Fibrobacter were lower in fermenter samples (8.2% and 0.7% respectively) than in ruminal samples (28.4% and 2.2% respectively). Fermenters were able to maintain a core prokaryotic community structure similar to the native microbial community in the rumen. Although protozoa populations were lost, maintenance of Fibrobacter and archaeal populations indicated that the model system supported a functional community structure similar to the rumen. This model rumen system may serve as a suitable tool for studying aspects of ruminal microbial ecology and may resolve some of the relationships between microbial community structure and function by providing control of experimental conditions.
在两项实验中，使用核糖体（r）RNA靶向DNA探针来比较样品中的关键微生物群，通过两个比较标准对一种瘤胃模型系统——双流连续培养发酵罐进行了评估。最初的实验测量了发酵罐中瘤胃微生物群体在240小时适应过程中种群结构的时间变化。发酵罐接种物中，以使用通用探针定量的总小亚基（SSU）rRNA的比例来衡量，细菌占34.9%，真核生物占60.1%，古细菌占6.8%。纤维素分解细菌属纤维杆菌在接种物中占总SSU rRNA的9.5%。发酵罐运行240小时后，平均丰度为细菌80.9%，真核生物6.1%，古细菌5.1%，纤维杆菌属占总SSU rRNA的6.6%。在第二项实验中评估了瘤胃和发酵罐种群结构之间的差异，并将样品分类为瘤胃、接种物或发酵罐（发酵罐运行96、120、144和168小时）。与瘤胃样品（细菌平均48.0%、古细菌1.3%和真核生物61.5%）相比，发酵罐样品中细菌（84.5%）和古细菌（2.1%）的相对丰度较高，真核生物（1.8%）的相对丰度较低。所有样品中纤维杆菌的相对丰度相似，平均为2.5%。瘤胃和发酵罐样品中琥珀酸纤维杆菌和琥珀酸纤维杆菌亚群3的比例相似（占纤维杆菌SSU rRNA的百分比）。发酵罐样品中纤维杆菌的琥珀酸纤维杆菌亚群1和肠道纤维杆菌比例（分别为8.2%和0.7%）低于瘤胃样品（分别为28.4%和2.2%）。发酵罐能够维持与瘤胃中天然微生物群落相似的核心原核生物群落结构。虽然原生动物种群消失了，但纤维杆菌和古细菌种群的维持表明该模型系统支持与瘤胃相似的功能群落结构。这种瘤胃模型系统可作为研究瘤胃微生物生态学方面的合适工具，并可能通过提供对实验条件的控制来解析微生物群落结构与功能之间的一些关系。
