Laboratory of Microbial Ecology and Technology (LabMET), Ghent University, Coupure Links 653, 9000, Ghent, Belgium.
Antonie Van Leeuwenhoek. 2013 Mar;103(3):527-37. doi: 10.1007/s10482-012-9835-7. Epub 2012 Oct 27.
Due to the increasing atmospheric concentration of the greenhouse gas methane, more knowledge is needed on the management of methanotrophic communities. While most studies have focused on the characteristics of the methane-oxidizing bacteria (MOB), less is known about their interactions with the associated heterotrophs. Interpretative tools based on denaturing gradient gel electrophoresis allowed to evaluate the influence of copper-an important enzymatic regulator for MOB-on the activity and composition of the bacterial community. Over 30 days, enrichments with 0.1, 1.0 and 10 μM Cu(2+) respectively, showed comparable methane oxidation activities. The different copper concentrations did not create major shifts in the methanotrophic communities, as a Methylomonas sp. was able to establish dominance at all different copper concentrations by switching between both known methane monooxygenases. The associated heterotrophic communities showed continuous shifts, but over time all cultures evolved to a comparable composition, independent of the copper concentration. This indicates that the MOB selected for certain heterotrophs, possibly fulfilling vital processes such as removal of toxic compounds. The presence of a large heterotrophic food web indirectly depending on methane as sole carbon and energy source was confirmed by a clone library wherein MOB only formed a minority of the identified species.
由于温室气体甲烷在大气中的浓度不断增加，我们需要更多地了解甲烷营养菌群落的管理知识。虽然大多数研究都集中在甲烷氧化菌（MOB）的特性上，但对它们与相关异养生物的相互作用了解较少。基于变性梯度凝胶电泳的解释工具可以评估铜（一种对 MOB 至关重要的酶调节剂）对细菌群落活性和组成的影响。在 30 天的时间里，分别用 0.1、1.0 和 10 μM Cu（2+）进行富集，结果表明甲烷氧化活性相当。不同的铜浓度并没有使甲烷营养菌群落发生重大变化，因为一种甲基单胞菌能够通过在两种已知的甲烷单加氧酶之间切换，在所有不同的铜浓度下建立优势地位。相关的异养群落持续发生变化，但随着时间的推移，所有培养物都进化为一种相似的组成，与铜浓度无关。这表明 MOB 选择了某些异养生物，这些异养生物可能承担了去除有毒化合物等重要过程。通过克隆文库证实了一个大型异养食物网的存在，该食物网间接依赖于甲烷作为唯一的碳源和能源，而 MOB 仅构成了所鉴定物种的少数。
