Julie Sung, 2011, Molecular Biology

The bacteria, Burkholderia pseuodmallei, which causes the disease melioidosis, is a disease that is endemic to Thailand and Northern Australia.  The bacteria live in the soil, are highly resistant to antibiotics, and cause respiratory infection.  If not treated properly, the fatality rate is 50%.  Melioidosis has been a neglected disease but has potential as a bioterrorism weapon.

Certain fosmids made from the DNA of B. pseudomallei that when inserted into E. coli bacteria, cause slow growth in the E. coli bacteria.  In order to test if the fosmids were causing the slow growth, the E. coli were cured of the fosmid to see if they returned to wild-type growth.  Electrocompetent E. coli bacteria were also transformed and tested to see if they acquired the slow growth phenotype.  As a control, E. coli were also grown while maintaining the presence of the fosmid.  Even though most of the E. coli were able to be cured and transformed, the slow growth phenotype was difficult to maintain.  This could be due to the E. coli overcoming the cause of slow growth over time.

One fosmid was able to be maintained, and transposon mutagenesis was performed on this fosmid to see if the wild type rate of growth could be recovered.  While this did not occur, two of the transposed fosmids grew more slowly than the original 15B23 strain.  The 15B23 fosmid is currently being sequenced and perhaps then a gene or genes can be identified that are responsible for the slow growth.