Completing the Genome of Nitrosospira briensis


Marlen Rice

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USU Student Showcase

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Faculty Mentor

Jeanette Norton


Human inputs of reactive nitrogen now exceed natural inputs into the global nitrogen cycle. An integral part of the nitrogen cycle is nitrification which is thought to be carried out to a large extent by ammonia-oxidizing bacteria (AOB) and archaea (AOA). Nitrification is connected to downstream biochemical reactions that lead to nitrate production and subsequent leaching into surface and groundwater. To better understand AOB's role in the nitrification process, further research regarding these organisms' genomes may provide clues to helping humanity understand the participants involved in nitrogen cycling.

Last year DNA from Nitrosispira briensis, a representative of ammonia-oxidizing bacteria from agricultural systems was isolated and sequenced at Dept. of Engergy Joint Genome Institute. JGI sequenced the majority of the genome, however due to repeating regions likely due to its repetitive central metabolism encoding genes, the genome was put into 31 contigs. The space between these 31 unconnected contigs represent considerable loss of genomic material in this bacterium . My project has been to connect the contigs from Nitrosospira briensis in order to find the actual alignment of genes in the genome as well as to discover any missing genomic material lost in the spaces between the various contigs. Analysis of Nitrosospira briensis and Nitrosospira multiformis will be contrasted to give a better generalization of AOB in agricultural systems.

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