Date of Award

Winter 2007

Project Type


Program or Major


Degree Name

Master of Science

First Advisor

Louis Tisa


Using a molecular approach (PCR), a group II truncated hemoglobin (trHb) gene was identified in several diverse isolates of Frankia. An analysis of three draft genome sequences for Frankia isolates EAN1pec, Ccl3, and ACN14a also revealed the presence of second trHb, homologous to group I trHbs. Phylogenetic analysis suggested that the Frankia trHb genes were grouped based on their respective genotype and clustered closest to Mycobacterium trHb genes.

Frankia strain Ccl3 was grown under a variety of environmental stimuli to evaluate the expression of trHbN and trHbO genes. Nitrogen status did not affect expression of either gene, while oxidative stress caused a decrease in expression levels for both genes. The expression of trHbO increased under low oxygen environments, suggesting a role in increasing respiration rates. The expression of trHbN increased in response to spontaneously generated nitric oxide, suggesting a role in the protection from reactive nitrogen species.