Date of Completion


Embargo Period



J. Peter Gogarten, Dave Knecht, Spencer V. Nyholm, Daniel Gage

Field of Study

Molecular and Cell Biology


Master of Science

Open Access

Open Access


Thermotoga maritima is the representative member of the order Thermotogales, which is comprised of extremely thermophilic anaerobic bacteria. All members of this order are characterized by the presence of a unique outer envelope, the toga. The outer envelope appears as polar cellular distensions that sometimes are as large as the cytoplasm. The outer envelope increases in size while the cytoplasm remains the same leading to an outer envelope distension. The outer envelope distension development and increase in its size most likely occurs for storage of nutrients. Initial observations suggest that cells create larger distensions at the poles as they enter stationary phase. Preliminary data showed an increase in the number of cells with larger outer envelope distensions from the mid-log to stationary phase. Comparative measurements of cells were taken in their respective growth phases to determine cytoplasm sizes. There was a significant (p=4.44E-31) increase in the ratio of the whole cell to the cytoplasm between the mid-log and stationary phases. There was a significant (p=1.25E-20) increase in the area of the outer envelope and an insignificant (p=0.02) increase in cytoplasm area between mid-log and stationary phase. This indicates a 1.69-fold increase in the outer envelope size while the cytoplasmic aspect of the cells remained the same. Furthermore, expression analysis was conducted to confirm growth phase specific gene expression. There was an increase in the expression of the (Outer membrane protein encoding genes) ompA1, ompB, ompA2 and ompA3 by 7.9 and 5.2, 3 and 2.2 fold respectively from mid-log to stationary phase. The beta barrel assembly machinery protein gene (bamA) showed only a 1.2 fold while the csaB was up regulated 4.4 fold between phases.

Major Advisor

Kenneth M. Noll