Mol Biol Cell 1992, 3:913–926 PubMed 51 Jenal U, Fuchs T: An ess

Mol Biol Cell 1992, 3:913–926.PubMed 51. Jenal U, Fuchs T: An essential protease involved in bacterial cell-cycle control. EMBO J 1998, 17:5658–5669.PubMedCrossRef Competing interest The authors declare that they have no competing interests. Authors’ contributions EYV designed and VX-680 performed the experimental work and drafted the manuscript. VSB participated in the design

of the study and performed some of the expression assays. CG did the protein structure modeling and analysis. MVM conceived the study, and participated in its design, coordination and helped to draft the manuscript. All authors read and approved the final manuscript.”
“Background Human activities, particularly agricultural practices and fossil fuel emissions, have greatly increased inputs of nitrogen (N) to terrestrial and aquatic habitats [1]. In agricultural regions, N is leached from soil in the form of nitrate (NO3-), which is often found in high concentrations

in groundwater and groundwater-fed surface waters [2, 3]. Moreover, high NO3- in surface runoff is often observed when fertilizer is used [4, 5]. These sources of NO3- pollution pose a particular threat to aquatic habitats where groundwater and surface runoff are a significant PRI-724 nmr or primary source of input. Vernal pools are temporary aquatic habitats that are common to temperate regions and filled by surface runoff following snowmelt, spring rain, and rising water table [6]. As such, N enrichment from NO3- leaching can alleviate N limitation and have a significant influence on N cycling. Because vernal pools are shallow depressions that often experience low dissolved oxygen concentrations [7–9], increased

NO3- availability can favor anaerobic N cycling processes, such as denitrification and anaerobic ammonium oxidation, while suppressing anoxic pathways adapted to low NO3- conditions, such as dissimilatory nitrate reduction to ammonium. N cycling is almost PJ34 HCl exclusively mediated by microorganisms; therefore high NO3- inputs can influence N cycling and also have cascading structural effects on the selleck chemicals microbial communities involved. By studying genes for the enzymes responsible for the conversion of N between oxidized and reduced forms, there have been large advances in our knowledge of microbial functional groups involved in N cycling [10, 11]. However, the N cycle is a complex network of pathways that can share some enzymes and can also be simultaneously influenced by the input of one nitrogenous compound, such as NO3- [12]. Therefore, studies which profile only one or a subset of N cycling enzymes may provide a limited view of how NO3- pollution impacts microbial processes. In addition, most previous studies on the effects of NO3- on microbial functional genes have limited their assessment to N cycling genes (e.g., [13, 14]), even though elevated NO3- is known to affect other microbial processes, such as those involved in C cycling (e.g., [15, 16]).

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