Honors College Thesis


Correlation of NE 1545 expression and cell size in Nitrosomonas europaea exposed to a suite of aromatic hydrocarbons Public Deposited

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  • Ammonia oxidizing bacteria, including Nitrosomonas europaea, are inhibited by aromatic hydrocarbons which can be found in wastewater treatment plants. In recent studies, changes have been observed in N. europaea cell size upon exposure to benzene, but not toluene. Additionally, NE 1545, a gene proposed to be involved in fatty acid metabolism, was up-regulated in response to benzene, but not toluene. This work presents the results of a series of short-term experiments where N. europaea was exposed to a variety of aromatic hydrocarbons, and cell size and NE 1545 expression were measured. It was found that exposure to compounds with a dipole moment of 1.5 D and greater (e.g. aniline, phenol, and p-cresol) resulted in the greatest decreases in cell size (5 to 6%), as well as the greatest up-regulation of NE 1545 (17- to 19-fold). Compounds with dipole moments less than 1.5 D (e.g. m-cresol, o-cresol, toluene, and p-hydroquinone) caused negligible changes in size and NE 1545 expression. It is hypothesized that the more polar aromatic hydrocarbons were accumulating in the membrane to which the cells responded by increasing the expression of NE 1545 and this resulted in changes in the cell membrane which resulted in decreases in cell size.
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  • description.provenance : Submitted by Heather Boren (heather.boren@oregonstate.edu) on 2009-07-24T18:17:32ZNo. of bitstreams: 1Caslin Gilroy Thesis.pdf: 484235 bytes, checksum: 48c45de7515c177476720254e32366ba (MD5)
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