Comparison of physiology and genome-wide expression in two Nitrosomonas spp. under batch cultivation

• Author / Creator

  Ghashghavi, Mohammad

• Ammonia oxidizing bacteria (AOB) play a central role in the nitrogen cycle by oxidizing ammonia to nitrite. Nitrosomonas europaea ATCC 19718 has been the single most studied AOB that has contributed to our understanding of chemolithotrophic ammonia oxidation. As a closely related species, Nitrosomonas eutropha C91 has also been extensively studied. Both of these bacteria are involved in wastewater treatment systems and play a crucial part in major losses of ammonium-based fertilizers globally. Although comparative genome analysis studies have been done before, change in genome-wide expression between closely related organisms are scarce. In this study, we compared these two organisms through physiology and transcriptomic experiments during exponential and early stationary growth phase. We found that under batch cultivation, N. europaea produces more N2O while N. eutropha consumes more nitrite. From transcriptomic analysis, we also found that there are selections of motility genes that are highly expressed in N. eutropha during early stationary growth phase and such observation was completely absent in N. europaea. Lastly, principle homologous genes that have been well studied had different patterns of expression in these strains. This study not only gives us a better understanding regarding physiology and genome-wide expression of these two AOB, it also opens a wide array of opportunities to further our knowledge in understanding other closely related species with regards to their evolution, physiology and niche preference.

• Subjects / Keywords

  • Ammonia oxidizing bacteria
  • Nitrification
  • Transcriptomics

• Graduation date

  Fall 2014

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3539V

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.