Date of Award


Document Type


Degree Name

Master of Science (MS)


College of Science and Mathematics



Thesis Sponsor/Dissertation Chair/Project Chair

Lee H. Lee

Committee Member

Kristen J. Monsen

Committee Member

John J. Gaynor

Committee Member

Quinn C. Vega


Due to high levels of heavy metal pollution in the environment, there has always been a high interest in organisms that have developed resistance to certain heavy metals of interest. Microorganisms such as Pseudomonas, E. coli, and Ralstonia, have been identified as being resistant to one or more heavy metals. Extensive work has been done with respect to mechanisms of resistance to heavy metals in a wide array of microorganisms. However, mechanisms of resistance are yet to be fully explored in some other microorganisms. One such example is the Cyanobacteria, Synechococcus sp. 625 (SIU 625), formerly classified under Anastycis nidulans. This microorganism has been known to show levels of resistance to Cu2+, Hg2+, and Fe2+. Understanding the exact mercuric resistance mechanism in this microorganism would bring the field of bioremediation closer to developing very effective systems for toxic waste clean up. The growth of SIU 625 in different concentrations of mercuric chloride was studied using direct count and turbidity study. The morphology of cells and DNA DAPI stain in different concentrations of HgCl2 were observed with Differential Interference Phase Contrast Fluorescence microscope (DIP). Genomic and proteomics analysis of all currently identified mercuric resistance genes in prokaryotes were carried out to determine their relationship to putative mercuric resistant genes in SIU 625. Primers for various genes encoding putative mercuric resistance were designed and amplification was attempted on both chromosomal and plasmid DNA from SIU 625. Expression levels of identified genes were then analyzed in relation to concentration and time of mercuric exposure cells. Arrangement of identified mercuric resistance genes were then compared to arrangement of generic mer operons.

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