Project description:This study evaluated the ammonium oxidizing communities (COA) associated with a potato crop (Solanum phureja) rhizosphere soil in the savannah of Bogotá (Colombia) by examining the presence and abundance of amoA enzyme genes and transcripts by qPCR and next-generation sequence analysis. amoA gene abundance could not be quantified by qPCR due to problems inherent in the primers; however, the melting curve analysis detected increased fluorescence for Bacterial communities but not for Archaeal communities. Transcriptome analysis by next-generation sequencing revealed that the majority of reads mapped to ammonium-oxidizing Archaea, suggesting that this activity is primarily governed by the microbial group of the Crenarchaeota phylum. In contrast,a lower number of reads mapped to ammonia-oxidizing bacteria.
Project description:Comparative gene expression on a co-culture of anaerobic ammonium and sulfur-oxidizing bacteria under ammonium and nitrate limitation
Project description:Nitric oxide (NO) has several important functions in biology and atmospheric chemistry as a toxin, signaling molecule, ozone depleting agent and the precursor of the greenhouse gas nitrous oxide (N2O). Even though NO is a potent oxidant, and was available on earth earlier than oxygen, its direct use by microorganisms for growth was not demonstrated before. Using physiological experiments, metatranscriptomics and metaproteomics, here we show that anaerobic ammonium-oxidizing (anammox) bacterium Kuenenia stuttgartiensis grow by coupling ammonium oxidation to NO reduction, and produce only N2. Such a metabolism could have existed on early earth, and has implications in controlling N2O and NO emissions both from natural and manmade ecosystems, where anammox bacteria contribute significantly to N2 release to the atmosphere.