title: Selection of associated heterotrophs by methane-oxidizing bacteria at different copper concentrations.
abstract: 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.
authors.affiliation: Laboratory of Microbial Ecology and Technology (LabMET), Ghent University, Coupure Links 653, 9000, Ghent, Belgium.
authors.forename: David
authors.initials: D
authors.lastname: van der Ha
authors.forename: Inka
authors.initials: I
authors.lastname: Vanwonterghem
authors.forename: Sven
authors.initials: S
authors.lastname: Hoefman
authors.forename: Paul
authors.initials: P
authors.lastname: De Vos
authors.forename: Nico
authors.initials: N
authors.lastname: Boon
mesh_terms: D058448:Biota; D003300:Copper / Q000378:metabolism*; D058645:Denaturing Gradient Gel Electrophoresis; D052836:Heterotrophic Processes; D008772:Methylococcaceae / Q000254:growth & development* / Q000378:metabolism*
chemical_list: D003300:Copper