Advancing the world of research

Turtles are excellent model organisms for conducting studies investigating long-term ecological principles. This is because turtles have long lives and are relatively easy to work with. Additionally, many turtle species are globally threatened because of human causes. Therefore, turtle research can provide insights into ecology generally and conservation specifically.

Our research is conducted in a series of three ponds located in the FHU wetland area. Turtles are systematically captured and a series of morphological measurements are collected from each turtle. Turtles are then permanently marked and released at the site of capture. Data collected from this study are used to evaluate population structures, growth rates, movements, and survivorship among turtle species. This study was begun in 1998, and over 200 turtles have been marked to date.

We are also members of the North American Freshwater Turtle Research Group. The NAFTRG consists of professional biologists and volunteers from across the country who are conducting long-term turtle community studies in Florida, Texas, and Horse Creek in Hardin County, Tennessee. Dr. Brian Butterfield is the faculty mentor of the team conducting this research.

Invasive species are a threat to biodiversity worldwide. Additionally, the damage caused by and the control of invasive species costs the U.S. well over a billion dollars annually. Therefore, it is important for biologists to understand the mechanisms of biological invasions if biologists are going to minimize the ecological and economic consequences of invasive species.

Over 40 reptile species have invaded the southeastern U.S. Among these are several gecko species. Our research is designed to identify behaviors that influence invasive characteristics and subsequent geographic expansion among invasive gecko species. Dr. Brian Butterfield is the faculty mentor of the team conducting this research.

West Tennessee has a very diverse amphibian and reptile fauna. However, the geographic distribution of many amphibians and reptiles in west Tennessee is poorly known. It is important for biologists to know the distributions of organisms if they are to adequately investigate the ecologies of specific species and appropriately address issues in conservation and biodiversity.

Our research involves documenting the occurrence of species previously unknown to science from specific areas. Our work has documented the occurrence of several species in new areas including two species found near our campus in Chester County. Dr. Brian Butterfield is the faculty mentor of the team conducting this research.

The species Pectobacterium carotovorum is one of several members of a group of enterobacterial plant pathogens commonly known as soft rot bacteria. These pathogens cause major economic loss to many soft tissue crops. Soft rot bacteria produce exoenzymes that degrade cell wall components of the infected plant, resulting in a collapse of plant cellular infrastructure and a leakage of intercellular components.

Our research team is investigating the genetic regulation of Pectobacterium carotovorum, specifically those genes whose function is linked to the production of plant cell wall degrading exoenzymes. We are collaborating with Dr. Korsi Dumenyo, a bacterial geneticists at Tennessee State University. Dr. Caleb Kersey is mentor of the team conducting this research.

Topoisomerases are critical cellular enzymes that disentangle DNA segments. These enzymes use a transient DNA break to carry out their function, which poses a risk to the cell. Anticancer and antibacterial drugs have been designed to target this enzyme to disrupt function and lead to cell death. Yet, some details of the mechanism and regulation of topoisomerase II are not clarified. In particular, how does the poorly understood C-terminal domain influence and regulate the function of the protein?

The focus of this research is on examining how the enzyme is controlled and regulated specifically through post-translational modifications and protein-protein interactions. This work involves experiments with purified topoisomerase II and includes site-directed metagenesis, DNA and protein purification, gel electrophoresis, PCR/RT-PCR and other methods. Dr. Joe Deweese is the research mentor overseeing this work.

Protein structure has been examined using both biochemical and computational approaches. One weakness of some of these methods is the inability to detect the relative importance of interdependencies within a protein sequence. Which amino acids are important for a given function? Which ones influence the roles of other amino acids? Some of these details can be teased out using complex biochemical experiments, while others may remain elusive. We developed the PSI-Calc bioinformatics tools in collaboration with several collaborators to help discover sequence interdependencies using multiple-sequence alignments of proteins. This information will help researchers examine proteins using a new set of data to complement biochemical and computational data from other experiments. We aim to use this software tool to study topoisomerase II and also apply it to other proteins. Dr. Joe Deweese is the research mentor overseeing this work.