8th Annual Undergraduate
Research Symposium
Abstracts should be formatted with information in the
following order:
The faculty advisor’s name in parentheses
Names of the presenters; if only one of the contributors
is presenting, his/her name should be followed by an asterisk.
Affiliation of presenters.
Abstracts should be no more than 250 words in length,
well written, and concise.
Please submit abstract electronically as a Microsoft
Word document (Times New Roman 12 point font) via email (jschuldt@uwsuper.edu)
or burned to a CD and delivered to Dr. Jeff Schuldt (MC 139-C).
Below is an example of a properly prepared abstract:
How
Selective is Galactose Utilization? A Comparison of the fitness of two Escherichia coli strains
in environments containing Galactose. (Dr. Ralph Seelke) Curt Alaspa*
and Salmaan Khan, Department of Biology and Earth
Sciences, University of Wisconsin-Superior, Superior, WI 54880
In order for evolution to occur, mutants must be able to out compete non mutants. This study examines the selective advantage of galactose utilization in Escherichia coli.. AB1157, a strain of E. coli that is unable to utilize galactose, was grown in competition with an isogenic galactose utilizing revertant, AB1157G. A 50:50 mix of AB1157 and AB1157G was grown overnight in various liquid media containing galactose. The number of each type before and after growth was determined by dilution and plating. These results were used to determine the relative fitness of AB1157G to AB1157. AB1157G does indeed appear to demonstrate a selective advantage over AB1157 when grown in galactose, but not as great as expected. A similar procedure was also performed to determine the long-term effects of competition between these strains. AB1157 and AB1157G were mixed together, with AB1157G being underrepresented in the mixture. After overnight growth, the culture was diluted one hundred-fold by transfer to fresh media and again grown overnight. This was repeated for nine days, using two different types of growth media. Again, fitness indexes were used to determine the long-term effects of competition. Under the most selective conditions, AB1157G demonstrated only a slight selective advantage over AB1157, increasing from 16 percent initially to 53 percent of the total culture through over 60 generations of competitive growth. This study raises serious questions as to whether galactose utilizing mutants can be found by long-term growth in selective media.