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Mac Law

Professor of Pathology

CVM Research Building 218A

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Grants

Date: 01/01/14 - 12/01/18
Amount: $460,000.00
Funding Agencies: US Fish & Wildlife Service

The robust redhorse (Moxostoma robustum) is a rare and imperiled, large catostomid fish found in only three regulated river drainages in the southeastern U.S. The species was originally described in 1870 from the Yadkin–Pee Dee drainage in North Carolina and is known to make seasonal migrations within freshwater systems. It has large pharyngeal teeth for crushing mollusks and other invertebrates known to sequester anthropogenic contaminants. The robust redhorse has been negatively affected by habitat modification and fragmentation from hydroelectric dams, introduced species, sedimentation, and water pollution and is protected by state endangered status in Georgia and North Carolina. Previous research by the Principal Investigators has shown that habitat suitability will be enhanced by prescribed flow augmentations from hydroelectric dam releases; however, the impacts of water quality and contaminant loads remain unknown. In addition to the unknown effects of traditional organic and inorganic contaminants, recent research suggests that the impact of emerging contaminants, such as endocrine disrupting compounds and pharmaceuticals, may be of significant detriment to fishes and other Wildlife Action Plan priority species in the Pee Dee River. These uncertainties must be resolved before additional and significant investments are made in population augmentation or other recovery efforts. To further elucidate the impact and potential threat of water quality and contaminant dynamics on the robust redhorse, the aquatic food web, and 53 priority aquatic species of the Pee Dee River, we propose six research objectives to pursue in the Pee Dee River of North Carolina and South Carolina. We will (1) conduct systematic field sampling of habitat and food web components, (2) conduct experimental field bioassay exposures with captively-propagated robust redhorse, (3) perform laboratory analyses of traditional and emerging contaminants on aquatic habitat and food web components and histopathology to identify intersex condition in fish (i.e., effects of endocrine disrupting compounds), (4) determine aquatic food web structure and pathways using stable isotope ratios, (5) develop population and food web models to describe and project effects of habitat and water quality modifications, and (6) synthesize results for robust redhorse recovery from population and ecosystem perspectives. This research is unique in that it will yield results and inference that are descriptive (systematic sampling), explanatory (experimental bioassays, food web analyses), and predictive (population and food web modeling) at multiple scales and across disciplines to inform decision making and management. The food web to be studied supports a total of 53 priority aquatic species (31 fishes, 21 mussels, 1 crayfish), 35 species in the NC Wildlife Action Plan and 26 species in the SC Comprehensive Wildlife Conservation Strategy that will benefit from this research. Our proposal addresses critical research needs identified by the Robust Redhorse Conservation Committee, South Atlantic Landscape Conservation Cooperative, and the State Wildlife Action Plans of North Carolina, South Carolina, and Georgia, and is supported by these consortia and state and federal natural resource agencies to guide management objectives and goals for species recovery and habitat restoration at the landscape level.

Date: 07/01/11 - 12/31/16
Amount: $489,788.00
Funding Agencies: NC Wildlife Resources Commission

The goal of this collaborative project is to better understand the causes and consequences of intersex in North Carolina water bodies and fish. This broad based project is truly multidisciplinary, with fishery biologists at NCSU and the NCWRC working with ecotoxicologists and veterinary pathologists to develop a mechanistic understanding of the biotic and abiotic factors that drive variation in the concentrations of Endocrine Disrupting Compounds (EDCs) in NC waterways as well as the extent and severity of intersex in fish. The project has six major components, all of which have links to the biology or management of sportfish. Objective 1: Develop a GIS-based map of potential Endocrine Disrupting Compounds (EDCs) in North Carolina water bodies . In this component of the project we will identify potential agricultural, municipal, and industrial sources of EDCs, ultimately producing a statewide reference map that would allow fishery biologists to identify areas of potential concern for game and nongame fishes. Objective 2: Conduct a statewide survey for the presence of EDCs in North Carolina water bodies and intersex in common fish. This aspect of the project develops a statewide assessment of intersex for key sportfish including black basses (Micropterus spp.), sunfish (Lepomis spp.), and catfish (Ictalurus or Ameiurus spp.). Specifically, we will measure the degree and severity of intersex in these fishes at 20 sites throughout North Carolina, at least ten of which are identified as ?hotspots? (agricultural, wastewater, or industrially-influenced sites that are expected to have significant concentrations of EDCs and, therefore, potentially high rates of fish intersex) from the GIS analyses in Objective 1. The remaining sites will be used as ?reference? sites (areas expected to have relatively low concentrations of EDCs and rates of intersex). We will also collect EDC data in water and sediment at each study site. This objective will directly assess the impact of EDCs in state waterways and how they impact important sportfishes. Objective 3: Quantify seasonal dynamics of EDCs and intersex in NC water bodies and fish. This objective builds upon the previous by specifically examining seasonal dynamics of EDCs in waterways and intersex in fish at four selected sites. One of those sites will be the Yadkin-Pee Dee River basin, where largemouth bass were found to have the highest incidence of intersex (64 ? 91%) of all species and systems studied in a recent national USGS study (Hinck et al. 2009). This component of the study asks if and how concentrations of EDCs, and rates and severity of intersex, change as a function of season in both impacted and reference systems. Once again, black basses, sunfish, and catfish will be the study organisms. Objective 4: Conduct intensive field research and experimental bioassays on intersex fish and EDC dynamics in the Pee Dee River system. This component of the investigation focuses on the highly-impacted Pee Dee River system and aims to collect longitudinal and caged-fish data to better understand EDC and intersex dynamics in fishes. Specifically, water, sediment, and fish will be collected from ten intensive study sites that span a broad range of longitudinal position, river and watershed size, land use patterns, and known point-source discharges. Water and sediment samples will be analyzed for estrogenic compounds and fish will be analyzed for intersex. Sportfish to be analyzed include black basses (Micropterus spp.) and sunfish (Lepomis spp). Objective 5: Laboratory assessment of endocrine disruption and intersex in Pee Dee River water mixtures. The purpose of this objective is to establish the direct relationship between exposure to endocrine disrupting compounds identified in Pee Dee river (as a representative ?hotspot?) to incidence of endocrine disruption and intersex in a model laboratory fish, the Medaka (Oryzias latipes). This analysis provides a controlled mechanism to establish a cause and effect relationship between EDC exposure and molecular an

Date: 01/01/13 - 7/31/15
Amount: $191,999.00
Funding Agencies: NC Department of Transportation

The Appalachian elktoe (Alasmidonta raveneliana) is found at geographically fragmented locations in Western North Carolina and Tennessee. The species is imperiled and was federally listed as endangered in 1994. The elktoe population in the Little Tennesse river in Western NC has experienced a precipitous decline since 2004. Preliminary studies suggest that rapidly expanding populations of an invasive species, the Asian clam (Corbicula fluminea), may be contributing to the decline. We propose to build on these preliminary studies and examine the likelihood that the nutritional health of Appalachian elktoe populations has been impaired. Sentinel A. raveneliana will be held at selected sites in the Little Tennessee and Tuckasegee rivers. Their survival and growth will be measured and their nutritional health status assessed relative to available seston and other food resources supporting their diets in the two rivers systems. Concurrent assessment of sediment microbial populations will facilitate the development of profiles of microbial communities and examination of relative changes over time at locations where they are in decline in the Little Tennessee and thriving in the Tuckasegee. Additional studies in the laboratory will be conducted to assess the role of different components of particulate organic matter in the growth and survival of A. raveneliana.

Date: 10/06/08 - 10/05/09
Amount: $5,000.00
Funding Agencies: ENVIRON International Corporation

This project involves assessment of liver pathology in wild-caught bullhead catfish, with an emphasis on liver cancer. NCSU's primary role will be to assess disease in the livers of these fish by both macroscopic examination and microscopically by the use of histopathology.

Date: 09/01/07 - 4/30/09
Amount: $74,159.00
Funding Agencies: Stroud Water Research Center

This proposal describes a series of experimental laboratory studies intended to test the response of several species of macroinvertebrates and fish collected from the Susquehanna River to various rates of diel temperature fluctuations. The experiments focus on rate of temperature change (i.e., °F/hour) as the main study variable while contrasting season (cold vs. warm) into the design. The study will examine sub-lethal responses in both macroinvertebrates and fish by avoiding temperature extremes in the test conditions that might cause mortality. A major challenge of this study is to test the degree of sensitivity of macroinvertebrates and fish to different rates of diel temperature change by using a gradient of fluctuating temperature regimes whose diel minima and maxima, as well as overall diel heat accumulation (degree days > 32 °F), do not stress or otherwise compromise the test animals. This means keeping experimental regimes slightly (i.e., a few degrees fahrenheit) cooler during warm season experiments and warmer during cold season experiments than might theoretically occur. Experimental endpoints (NCSU portion): for the fish, the study will measure biomarkers of stress, growth/nutritional status, fecundity, and health/disease status (histopathology).

Date: 09/01/06 - 2/29/08
Amount: $8,100.00
Funding Agencies: Morris Animal Foundation

Injection-site sarcomas (ISSa) are an iatrogenic tumor of cats that arises at the site of a previous vaccination or other injection. Although the prevalence of this disease is thought to be rather low, with estimates ranging from 1 in 10,000 to 1 in 1,000 cats at risk(1-4), it has devastating consequences to cats that develop such a sarcoma. Attempts to determine the pathology that results in neoplastic transformation of an injection site sarcoma have previously focused on a candidate gene approach. We propose to broadly evaluate gene expression in both injection site reactions as well as within injection site sarcomas using microarray technology. A human gene array with almost 10,000 known genes has been used successfully for the evaluation of a feline cell line, and we propose to use this array in these studies. Gene expression in these two abnormal tissues will be compared with gene expression in normal tissues. Our hypothesis is that there is sufficient homology between the feline and human genomes to allow us to use a human gene array to examine feline tissues. Our objectives are two-fold: to analyze gene expression in normal feline tissues and to obtain preliminary data on global gene expression in injection site reactions and injection site sarcomas. Our intention is to use this data to formulate preliminary hypotheses on which genes may play a role in neoplastic transformation and progression. Ultimately this work may lead to the identification of potential therapeutic targets both for the prevention and treatment of this disease.

Date: 06/15/06 - 12/31/07
Amount: $22,000.00
Funding Agencies: US Dept. of Defense (DOD)

a) Background -The land resources of the Department of Defense (DoD) are essential for military training and testing activities and for providing important habitat for more than 300 federally protected plant and animal species. There is increasing concern that training and testing activities could be compromised by land-use restrictions designed to protect threatened and endangered species (TES) and their habitat. Conflicts between mission activities and TES protection could become even more commonplace in the future as lands surrounding military facilities are further urbanized, locally-available TES habitat shrinks, and more species are placed on federal or state TES lists. Presently, land use decisions must often be made where there is limited available information on the TES of concern, and where the relationship between military activities and potential impacts on the species is poorly understood. Conventional population or community level surveys are the methods most commonly used to evaluate TES, but these techniques can be expensive, time-consuming, and relatively insensitive to environmental stressors with long response times, and measurements may provide only weak causal links between military activities and apparent effects. Improved, sensitive, and cost-effective methods are therefore needed to objectively monitor and evaluate the potential effects of military activities on TES. b) Objective - The purpose of this study is to develop and apply a cost-effective and field-transferable bioassessment tool that can be used across a wide-variety of military installations to assess the fitness of TES populations by measuring a suite of sensitive and rapidly-responding physiological indicators. Specifically, we will (1) identify appropriate physiological indicators of environmental stress for terrestrial TES, (2) apply and quantify these physiological stress indicators for TES by conducting experimental field studies at two DoD sites, and (3) determine the biological significance of these physiological indicators to the health and fitness of TES individuals and populations. The bioassessment tool developed from this study will enable the military to address the following important questions: (1) are there measurable sublethal or physiological stress responses of TES at DoD sites, (2) if so, what is the cause, (3) what is the ecological significance of physiological stress relative to the survival, health, and fitness of TES individuals and populations, and (4) if TES are not adversely affected by current military activities, can the footprint of these activities be increased without causing measurable harm to the wildlife species of concern? c) Process/Technology - To achieve the objectives of this study, field investigations will be conducted at Eglin AFB and at the Camp Shelby Training Site on representative terrestrial TES from two major vertebrate groups; amphibians (frogs) and reptiles (tortoises). The tools and approaches developed in this study to quantify sublethal physiological stress and evaluate its biological significance to TES are unique because (1) a suite of physiological indicators will be used to assess sublethal stress effects on TES, (2) sublethal stress indicators will be related to reproductive and population-level indicators to determine the biological significance of physiological stress to the health and fitness of TES populations, and (3) a bioassessment protocol will be developed and applied for evaluating effects of military activities on the fitness of TES populations by using sensitive and rapidly-responding physiological indicators. d) Transition Plan- The transition plan developed for this study will allow this approach to be applied across a range of military facilities to address various site-specific mandates of the Endangered Species Act. We will develop and provide written guidance that trains environmental management staff at military installations to use this tool in addressing issues related to TES. Environmental managers at Eglin AFB and Camp Shelby can test and implemen

Date: 07/01/05 - 12/31/07
Amount: $53,300.00
Funding Agencies: Hill's Pet Nutrition

Chronic diarrhea, especially osmotic diarrhea, in dogs can be caused by many different factors including infection, diet (food allergies), intestinal diseases and maldigestion, resulting in large volumes of loose and watery stools. This can lead to dehydration, malabsorption, loss of serum proteins and loss of electrolytes. Other disease conditions such as infections or cancer can lead to GI distress as well. The objective of this study is to determine the effect of a dietary intervention of a highly digestible diet, with important nutrients for the GI tract, in the treatment of chronic diarrhea in dogs. Dogs with diarrhea will be recruited from the clinic. Criteria for chronic diarrhea include persistent chronic diarrhea for at least 3 weeks or intermittent diarrhea for at least 3 months. We would like to recruit 12 dogs for the 6 week crossover dietary treatment study, 6 to be on the control diet and 6 on the test diet for a period of 3 weeks followed by the crossover. Both diets will be nutritionally adequate and indicated for GI distress. The stool quality rating and other measures will be taken for the entire duration of the study. Results of the study will be based on stool quality.

Date: 04/23/07 - 8/31/07
Amount: $91,535.00
Funding Agencies: US Dept. of Defense (DOD)

Studies will be conducted tol examine the relationship between levels of a mixture of PCB concentrations on the tissue accumulation response as well as valve gape in non-native, Corbicula fluminea and native, Elliptio complanata bivalve species in a controlled laboratory study. BioBay valve gape technology (clam test fixtures, CTFs) designed by Nekton Inc. will be used to test the efficacy of utilizing a warning system with biological indicator organisms (i.e. bivalves). This study will be conducted from the spring thru summer of 2007 and will extend the previous research. Histopathology (i.e. cellular damage) measures will be used to evaluate the baseline tissue response of bivalve species to a range of PCB dose levels, including a potential threshold response. The goal is to determine whether valve gape changes significantly with PCB tissue accumulation. The second part of the study will include a field study (1 month) where deployments of C. fluminea and E. complanata into known PCB sites (in and around Lake Crabtree, NC) with high levels of PCB contamination in the water column and sediment will be compared to a control or less PCB impacted site.

Date: 04/01/06 - 6/30/07
Amount: $16,333.00
Funding Agencies: Seine-Aval Public Interest Group

It has been shown in the course of previous exercises that sediments from the upstream part of the Seine estuary are genotoxic and that the genotoxicity is associated with the presence of polycyclic aromatic hydrocarbons (PAHs) and polar compounds that have not yet been identified. It has also been shown that these compounds are directly bioavailable and partially accumulated in organisms such as bivalves. Although they are very exposed, these creatures show relatively little damage to their DNA. In contrast, the ability of fish in the estuary to bio-activate the pro-genotoxic substances means they are at higher risk of genetic damage. Such damage can eventually result in increased mortality, reduced fertility and growth, and an increased risk of tumors and congenital malformations. It has, for example, been shown that 5% of the flounders in the Seine bay have liver tumors or pre-tumoral hepatic lesions (Cachot, 1998), and the biological performance of these fish is poorer than is found in flounders from the Ster estuary (Marchand et al., 2004). In view of the threat that genotoxic substances, and in particular PAHs, present to the survival, growth and renewal of fish populations, it seemed to us of fundamental importance to determine (i) whether there was a causal relationship between exposure to PAHs and the damage actually observed in relevant species; (ii) the nature and extent of effects produced at various levels in the organization of living species, over various timescales and at various stages of development. An initial study was carried out in 2005, on medaka embryos directly exposed to Seine estuary sediment (at Oissel). The aim was to simulate the contamination conditions of fish embryos developing in contact with the sediment in the Seine estuary. The preliminary data revealed a significantly increased mortality rate for the embryos and larvae, and also a significant increase in skeletal malformations and somatic mutations in the juveniles. The study provided proof that the eggs were contaminated directly from contaminated sediments, and that irreversible harmful effects resulted from this exposure. The study is currently continuing, so as to assess the incidence of tumors, growth rate, an index of general health, and the adults? fertility. We are proposing to go further in 2006 in analyzing the genotoxic risk associated with contamination in the Seine. This time, we would like to study the contamination of fish through the food chain. It should be possible to carry out initial experiments simulating contamination of the fish species that feed on microcrustaceans in the Seine estuary, so as to draw up the most complete clinical picture possible of the resulting biological effects. Japanese medaka juveniles will be fed for a month on nauplii of Artemia salina that have been exposed to an organic extract of sediment from the Seine estuary. The accumulation of PAHs, and the effects subsequently produced ? in terms of adducts, somatic mutations, tumors and other physiological disturbances ? will be monitored during the nine months following exposure. A second set of experiments will be carried out, under the same conditions but in this case using a model PAH, benzo[a]pyrene. This second study should enable a link to be established with the biological effects caused at various levels in the organization of living species. The emphasis will be put on the relationship between genetic damage and physiological disturbances. The ultimate aim will be to have, for a model fish species, a risk scale linking levels of exposure to the extent of effects caused at various levels in the organization of living species, over various timescales.


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