Enhance and Protect America's Natural Resources

Preserving Our Resources for Future Generations

Fate and Remediation of Emerging Contaminants (Pharmaceuticals, Antimony, and Tungsten) in the Environment

Impacts of Past and Current Land Uses on Eastern Hellbender (Cryptobranchus alleganiensis) Occupancy and Disease Prevalence in Tennessee: Implications for Conservation of High-Quality Watersheds

Occurrence of Pharmaceuticals and Personal Care Products (PPCPs) in Aquatic Environment in Middle Tennessee Sub Watersheds

Mechanistic Studies of Protein Tyrosine Kinase Activation by Environmental Toxicants

Characterization of Microbial Community Diversity and Potentials for Enhancing

Enhanced Study of Climate Change & Terrestrial Biogeochemistry using Integrated Models 

 Fate and Remediation of Emerging Contaminants (Pharmaceuticals, Antimony, and Tungsten) in the Environment
Dr. Sudipta Rakshit
Modern world is faced with various environmental challenges due to growing population and the need for advanced technology which caused over-exploitation of natural resources and introduction of new chemical substances to the environment that are not yet designated as pollutants. These 'emerging contaminants' are poorly studied, unregulated and have suspected properties that are detrimental to human and ecological health. Here I propose to study three major "emerging contaminants":  antibiotics, antimony, and tungsten. These contaminants have reported toxicological properties towards either human or the ecosystems. I plan to undertake a comprehensive approach to understand the behavior of these pollutants in the environment.  Laboratory-scale wetchemical, spectroscopic, and surface complexation modeling approaches will be used to decipher the molecular mechanisms of the interactions of these contaminants with environmental surfaces. After the comprehensive understanding, a risk-assessment guideline will be developed to address the major issues.

Impacts of Past and Current Land Uses on Eastern Hellbender (Cryptobranchus alleganiensis) Occupancy and Disease Prevalence in Tennessee: Implications for Conservation of High-Quality Watersheds
Dr. William Sutton
Anthropogenic habitat disturbances represent one of the greatest challenges to long-term conservation of native species and habitats. Although urbanization is commonly identified as the primary causative factor behind the loss of native habitats and biodiversity, conversion via other anthropogenic uses, including agriculture, also serve as a primary stressor to these landscapes. It is estimated globally that cropland or permanent pasture already covers more than half of all agriculturally suitable land, while temporary grazing or degraded/inactive farming operations account for a considerable amount of the remainder. Furthermore, production-scale agriculture has been implicated in declines of a greater number of imperiled organisms than any other anthropogenic disturbance.  In addition to direct impacts to the landscape, anthropogenic disturbances often cause additional environmental impacts,  including declines in water quality. The objectives of our study is to use the Eastern Hellbender (Cryptobranchus alleganiensis),  which is a large (up to 2 feet total length) fully aquatic salamander native to the eastern United States. This species, which is declining rapidly throughout its entire geographic range, is highly dependent on well-oxygenated, free-flowing, high-quality aquatic environments and therefore serves as an excellent indicator of environmental quality. We will use C. alleganiensis as a model organism to identify areas of high water quality throughout the state of Tennessee. Results from our study will provide managers and conservation agencies with a mechanism to identify landscapes of high conservation concern. Ultimately our data have the potential to increase protection and conservation of high quality landscapes and watersheds throughout the state of Tennessee.

Occurrence of Pharmaceuticals and Personal care Products (PPCPs) in Aquatic Environment in Middle Tennessee Sub Watersheds  
Dr. Sam Dennis
Pharmaceuticals and personal care products (PPCPs) have become important chemicals of emerging concern in surface and ground water resources. They have been shown to be relatively stable in an aquatic environment and may negatively impact aquatic ecosystems. On a national and regional scale, pharmaceutical drugs that are detected include steroids, prescription, and over the counter drugs such as antibiotics, anti-depressants, anti-inflammatory drugs, including both human and farm animals' hormonal drugs. Their concentration ranges from parts per trillion to parts per billion in sewage treatment plants effluent and surface water environment especially around outfall discharges. It is noteworthy that many of these chemicals are suspected or are potential endocrine-disrupting chemicals, as well as having the potential for adverse environmental effects. While water is a renewable resource, it is also a finite resource; hence both water quality and quantity are very important for human health and ecosystem sustainability. Our central hypothesis is that the incidence of pharmaceuticals and personal care products in surface water in urban and rural watersheds exist, partly due to catchment land uses and outfall discharges. Certainly studies of these chemicals in water bodies in Middle Tennessee rural and urbanizing watersheds are minimal.

Mechanistic Studies of Protein Tyrosine Kinase Activation by Environmental Toxicants
Dr. Ryan Beni
Metals (e.g., cobalt, cadmium, lead, arsenic, nickel) are important environmental toxicants. The exposure to toxic metals or  metal-containing particles at elevated concentrations is believed to be associated with increased risks of cancer, neurotoxicity,  and immunotoxicity. Such environmental toxicants can be detrimental to plants and animals, affecting the quality of products,  such as vegetables, eggs, dairy products, meats and fish. The molecular mechanisms by which metals cause toxicity are still  poorly understood. A number of these metals affect specific tyrosine kinases in cell signal transduction pathways involved in cell  proliferation, differentiation, and apoptosis. Cadmium stimulates osteoclast formation by activating cellular Src (c-Src) and leads  to decreased bone mineral content. Arsenite activates Protein Tyrosine Kinases, such as c-Src and the epidermal growth factor  receptor (EGFR). Parallel activation of c-Src and EGFR has been identified in many human cancers. However, the detailed  molecular mechanism(s) by which these events occur are not known.  A critical tyrosine residue at the C-terminal of Src is phosphorylated by the Protein Tyrosine Kinase Csk (C-terminal Src kinase),  which leads eventually to modulation of the c-Src three-dimensional structure and its inactivation (closed conformation). The  hypothesis underlying this project is that metals directly interact with a specific metal binding site located in the C-terminal of  several tyrosine kinases and lead the conversion of closed inactive conformation to open active conformation.  The structural consequences of direct metal binding to a number of tyrosine kinases (e.g., Src, Lck, Fyn, c-Abl, EGFR), and  their impact on kinase activation will be studied and compared. Biochemical and cell-based approaches will be used to examine  this hypothesis in three specific aims. The mechanism of the interaction of tyrosine kinases with metals will be studied by  analyzing the structural changes of different domains of tyrosine kinases and their correlation with the kinase activity in the  presence and absence of the metals. To characterize the interdependence between the signaling pathways, specific kinase  inhibitors and kinase-deficient cells will be used in the presence of metals. Based on these studies, specific metal-binding  inhibitors will be designed to be used in mechanistic studies and to investigate the effects of metal binding on the structure of  cysteine-containing peptides. The elucidation of metal-induced signal transduction processes will help to identify novel  molecular targets for the treatment of toxicity resulting from metals exposure.

Characterization of Microbial Community Diversity and Potentials for Enhancing
Dr. Emmanuel Dzantor
The world is facing multiple challenges of environmental, energy and food securities all exacerbated by climate change.   Bioenergy has been promoted as one solution to modulate these challenges. At first sight, the concept of 'growing energy'  appeared to be unquestionably appealing; bioenergy production and use can slow down projections of climate change and   prospects of massive biomass production for bioenergy could greatly boost agricultural production and revitalize rural  economies. However, bioenergy production is limited by available arable land to produce food, feed, fiber as well as  bioenergy. It is noteworthy that the feedstocks that are promoted for bioenergy (grain starch, soybeans, canola, and palm oil)  are the same crops for food and feed. Not surprisingly, bioenergy quickly sparked often contentious debates over food versus  fuel.   The US Department of Energy (DOE) anticipated the unsustainability of food-based bioenergy production; accordingly, it had  long committed vast amounts of resources to finding non-food crop alternatives for bioenergy production. This investment led to  the selection of switchgrass as the model bioenergy feedstock, based on desirable characteristics, including high biomass  production, wide geographic distribution and abiotic stress tolerance. However, finding non-food alternatives for bioenergy  production is only a partial solution to the food versus fuel dilemma. As some have correctly pointed out even most efficient  non-food crop still require land, water nutrients and other inputs that compete with food production.  Still, the enthusiasm that waned with recognition about untenable food versus debates is back in the upswing as various land  assessments and estimations continue to show that bioenergy biomass can be produced sustainably on marginal, degraded,  abandoned as well as contaminated lands without competition with prime agricultural land or ecosystem destruction. According  to one study, such problem lands can be used for biofuel feedstock production to meet up to 55% of current world fuel  consumption without affecting food and forage production. In other words, bioenergy feedstock can be produced on degraded  lands while saving prime agricultural land for food, feed and fiber. Now, the challenges are to find out how to produce biomass  sustainably on degraded land and how much biomass can degraded land actually produce?  With assistance from the Tennessee Natural Resource Conservation Service (NRCS), the PI has identified sites in Middle Tennessee that can used to demonstrate the concept of enhanced bioenergy biomass production capitalizing on soil  amendment with agricultural byproducts, microbial augmentations and long proven cover cropping that incorporate legumes in  biomass production systems. It is well established that biomass crops such as switchgrass have the ability to produce  considerable amounts of biomass even under less than prime land conditions soils and with minimum inputs. In fact, one of  their desirable attributes is their ability improve quality of soils and water while producing biomass. Before implementing such a  project in the field, this project proposes to test in greenhouse, the enhancement strategies and/or their combinations that are  likely to produce the best results from standpoints of sustainable biomass productivity and environmental protection and  enhancement. If the proposed project is successful it will lead to field implementation, with benefits for landowners throughout  the region and nation who are currently burdened by unproductive, marginal, degraded, contaminated and abandoned lands  that can be brought to profitable productivity.  The proposed project seeks to understand soil microbial communities, which are key drivers of functioning of ecosystems including degraded ones. They are responsible for cycling nutrient for plants' uses for primary production and they are critical for plant-mediated ecosystem processes including restoration and rejuvenation of degraded lands and carbon sequestration a major pathway for lessening of ills rising anthropogenic greenhouse gases in the first place. This project proposes to use combinations of characterization techniques to provide greater understanding of SMCs in degraded land and thereby facilitate their beneficial exploitation not only for enhanced biomass productivity for bioenergy but also improve soil and environmental quality and revitalize economies of landowners and growers.

Enhanced Study of Climate Change & Terrestrial Biogeochemistry using Integrated Models
Dr. Jainwei Li
Humans are changing Earth's climate and global surface air temperature has increased by about 1°C since 1900, and another  2~6°C is expected at the end of this century even if anthropogenic greenhouse gas (GHGs) emissions stopped immediately.  This major climate warming is disruptive to human society and natural ecosystems that support human society. While accurate  predictions of climate change have remained elusive. Because of the strong link between concentrations of atmospheric CO2, C and Earth's climate warming, understanding the drivers of biogeochemical transformations of soil carbon and CO2 release has  become a research priority.  In spite of continuously increasing volume of experimental data collections, studies however are insufficient to employ statistical  and synthetic approaches to comprehensively extract useful information from a wide range of datasets. It is also extremely rare  to integrate data and model and via such an integration to inform both future data collection and model projection. The state-of-the-art technological development and supercomputing capacity enable us to synthesize and integrate data and quantitative  model together in order to facilitate our exploration of the critical biogeochemical issues. This proposed study will not only  conduct field and laboratory experiments but also employ quantitative modeling and data synthesis approaches to elucidate soil  transformation under warmer temperature. 

 

 

 

 

 





webpage contact:
SACS