Construction and Analysis of Pasteurella haemolytica Mutants
This project focuses on the construction and analysis of Pasteurella haemolytica mutants that are unable to synthesize certain cell constituents. Bacterial genes encoding cell proteins are mutated by recombinant DNA techniques in the laboratory. Mutants are analyzed to determine the functions of the proteins that are no longer produced and the roles of those proteins in pneumonic pasteurellosis.
Sponsor: Oklahoma Agricultural Experiment Station
PI: George L. Murphy
Molecular Analysis of Pasteurella haemolytica Outer Membrane Proteins
Outer membrane proteins are frequently important contributors to the pathogenic potential of disease-causing bacteria. This research utilizes DNA cloning and sequencing to determine the identity of numerous Pasteurella haemolytica outer membrane proteins that elicit a strong immune response in the bovine host. The importance of the host immune response in preventing pneumonic pasteurellosis is also under investigation.
Sponsor: Oklahoma Agricultural Experiment Station
PI: George L. Murphy
Molecular Analysis of Pasteurella haemolytica Major Outer Membrane Proteins
Outer membrane proteins are frequently important contributors to the pathogenic potential of disease-causing bacteria. Research to determine the identity of the most abundant Pasteurella haemolytica outer membrane proteins utilizes DNA cloning and sequencing of the genes that encode those proteins. Additional experiments examine the role of the bovine host immune response to these proteins in preventing pneumonic pasteurellosis.
Sponsor: United States Department of Agriculture
PIs: George L. Murphy and Anthony W. Confer
A Survey of Ehrlichia Species in Dogs and Ticks in Oklahoma Using the Polymerase Chain Reaction
Several species in the genus Ehrlichia are tick-borne pathogens of humans and animals. This research utilizes the Polymerase Chain Reaction to examine the prevalence of Ehrlichia chaffeensis, the causative agent of human ehrlichiosis, and E. canis and E. ewingii, two canine pathogens, in dogs and ticks from within Oklahoma.
Sponsor: College of Veterinary Medicine Companion Animal Fund
PIs: George L. Murphy and Sidney A. Ewing
Characterization of Anaplasma marginale in Ticks
We studied Anaplasma marginale, a tick-borne rickettsia that causes the disease anaplasmosis in cattle, in ticks. We have described the role of male ticks in transmission of anaplasmosis. Male ticks are suspected to be an important vector of A. marginale, especially in winter months when the one-host tick, D. albipictus, is active.
Sponsor: Oklahoma Agricultural Experiment Station
PI: Katherine M. Kocan
Developmental Stages of Anaplasma marginale in Cell Culture
Anaplasmosis, a hemoparasitic disease of cattle caused by Anaplasma marginale, has not been cultivated in cell culture. We propagated the rickettsia in cultured tick cells and are describing its developmental cycle. This is the first reported propagation of Anaplasma marginale in cell culture.
Sponsor: Oklahoma Agricultural Experiment Station
PIs: Katherine M. Kocan and Edmour F. Blouin
Entomopathogenic Nematodes as Control Agents for Ticks
Entomopathogenic nematodes have been developed for biological control of certain insect pests, including grass turf grubs and Japanese beetles. We are testing the use of entomopathogenic nematodes as a biological control method for ticks. Engorged females of several species of ticks were found to be susceptible to invasion by nematodes.
Sponsor: U.S.-Israel Binational Agriculture Research and Development Fund (BARD)
PIs: Katherine M. Kocan and Edmour F. Blouin
Propagation of Anaplasma marginale in Tick Cell Culture
Anaplasmosis, a hemoparasitic disease of cattle caused by Anaplasma marginale has not been cultivated in cell culture. We propagated the rickettsia in cultured tick cells and are describing its developmental cycle. This is the first reported propagation of Anaplasma marginale in cell culture.
Sponsor: United States Department of Agriculture
PIs: Katherine M. Kocan and Edmour F. Blouin
Development of a Molecular Diagnostic Test for Feline Tularemia
This study utilizes in situ hybridization to detect Francisella tularensis (the etiology of tularemia) in archival tissue sections. Regions of the 16S ribosomal RNA gene were used to develop specific DNA probes. Use of these specific DNA probes have proven to be successful in the rapid diagnosis of tularemia.
Sponsor: College of Veterinary Medicine Companion Animal Fund
PI: R. Jay Hoffman
Role of Pasteurella haemolytica Leukotoxin in Shipping Fever Pneumonia
Shipping fever pneumonia, caused by the bacterium Pasteurella haemolytica, costs consumers more than $500 million annually. This bacterium produces a protein toxin that injures cattle white blood cells. Elucidation of the basic biology of leukotoxin specificity, structure, and function may provide information beneficial for development of drugs or vaccines able to block leukotoxin.
Sponsor: Oklahoma Agricultural Experiment Station
PI: Kenneth D. Clinkenbeard
Specificity of Pasteurella haemolytica Leukotoxin Binding
Pasteurella haemolytica leukotoxin intoxicates only ruminant white blood cells. Our goal is understanding the mechanism determining Pasteurella haemolytica leukotoxin target cell specificity. Leukotoxin will be purified and labeled with radioactive iodine, and its binding to ruminant white blood cells will be studied.
Sponsor: USDA (NRI)
PIs: Kenneth D. Clinkenbeard, Joseph McCann, and Anthony W. Confer
Bovine Respiratory Disease
Mechanisms of disease, vaccine development and efficacy, diagnostic approaches, and molecular biology of several bacteria and viruses are currently being investigated because they are significant causes of respiratory diseases in cattle. To accomplish these areas of focus, scientists are: (1) determining the mechanism by which a toxin (leukotoxin) produced by the bacterium Pasteurella haemolytica kills white blood cells from cattle and how that toxin stimulates the inflammatory response, (2) studying the immune response to P. haemolytica leukotoxin and outer membrane proteins to determine what constitutes an effective immune response, (3) analyzing the molecular genetics of P. haemolytica especially as it relates to the outer membrane, (4) comparing viral vaccines to determine their efficacy and long-term immunity, and (5) developing molecular methods for diagnosing Bovine Herpesvirus-5 infection in cattle.
Sponsor: Oklahoma Agricultural Experimental Station
PIs: Anthony W. Confer, Robert W. Fulton, George L. Murphy, Roger J. Panciera, Kenneth D. Clinkenbeard, Rebbeca J. Morton, and Jean M. d'Offay
Research Assistants: Karamjeet Pandher, Parameshwar Mahasreshti, and Mady Dabo
Outer Membrane Proteins in Immunity to Pasteurella multocida Serogroup A
Pasteurella multocida is a cause of pneumonia in dairy calves and feedlot cattle. Currently available vaccines are of questionable efficacy. Outer membrane protein (OMP) profiles from isolates of P. multocida obtained from cattle are being compared in this project. The immune response of cattle to the major OMPs are being quantified, and those responses are being correlated with resistance and susceptibility to experimental challenge. Once those areas are accomplished, the project will characterize the immunologically important OMPs as to amino-terminal sequences. Finally, the project will attempt to develop efficacious vaccines for P. multocida using OMPs or iron-regulated OMPs as the basis of the vaccine.
Sponsor: Oklahoma Agricultural Experiment Station
PIs: Anthony W. Confer, George L. Murphy, Rebbeca J. Morton, and Roger J. Panciera
Characterization and Immunologic Significance of the 30 kDa Outer Membrane Protein (OMP) of Pasteurella haemolytica
Pasteurella haemolytica is the major cause of severe respiratory disease in beef cattle. This project is characterizing two OMPs of P. haemolytica. Both proteins are of similar size. One protein shares amino-terminal sequence with the OmpA family of outer membrane proteins and is heat modifiable. The other has an amino-terminal sequence that is not similar to others as heretofore described. Cattle vaccinated with live P. haemolytica and are resistant to challenge have high antibody responses to these proteins, whereas cattle that are not resistant to challenge have low antibody responses to these proteins.
Sponsor: AVMA Foundation
PIs: Anthony W. Confer and George L. Murphy
Research Assistant: Parameshwar Mahasreshti
Development of an Effective Immunizing Agent against Pasteurella haemolytica
Currently available vaccines against bovine pneumonic pasteurellosis (shipping fever) have questionable efficacy. This project is studying the efficacy of an outer membrane/leukotoxin-based vaccine to protect cattle against shipping fever. The role of iron-regulated outer membrane proteins as immunogens are being studied as well.
Sponsor: Diamond Animal Health
PIs: Anthony W. Confer, Kenneth D. Clinkenbeard, Roger J. Panciera, George L. Murphy, and Rebbeca J. Morton
Development of the Cotton Rat as a Biomonitor of Trinitrotoluene Contamination
The U.S. Army has a major environmental problem due to contamination of soil and water with residues of TNT at many military facilities. The purpose of this project is to develop an extensive set of assays to allow evaluation of the mechanistic aspects of the pathogenesis of TNT toxicity. The cotton rat, Sigmodon hispidus, will be used due to the interest of the U.S. Army and the EPA in this species and due to our experience with this species. These results will advance the knowledge of the pathogenesis of TNT toxicity and, in addition, will help determine the severity and sensitivity of the cotton rat to TNT. We will use the information gained from this grant to determine which assays may be suitable for use with our cotton rat in situ biomonitor of environmental contamination as it relates to munition chemical contamination. This grant expands work of an U.S. Army grant.
Sponsor: University Center for Water Research
PIs: Charles Qualls, Jr. and Subbiah Sangiah
Research Assistant: A.M. Sundeep Chandra
Biochemical Effects of 2,4,6-Trinitrotoluene in Cotton Rats (Sigmodon hispidus)
These studies were designed to evaluate the toxicity of 2,4,6 trinitrotoluene (TNT) in the cotton rat (Sigmodon hispidus). The test studies performed include acute oral toxicity, peracute (five hour) toxicity, and subacute (seven day) toxicity studies. The effect of TNT on the cotton rat and mechanisms of toxicity are being studied. Emphasis is being placed on the biochemical effects (enzymatic assays), gross and microscopic pathology, hematology, and clinical chemistry. The purpose of these studies is to serve as an initial broad based evaluation with simultaneous examination of multiple toxicologic, pathologic, and metabolic parameters in the cotton rat, a mammalian biomonitor of environmental contamination.
Sponsor: U.S. Army Biomedical Research and Development Laboratory
PI: Charles Qualls, Jr.
Research Assistant: A.M. Sundeep Chandra
In Situ Dose-Response Relationships of a Mammalian Multiparameter Model for Assessing Petrochemical-Induced Ecotoxicity
The purpose of this project is to determine the ability of a mammalian multiparameter model developed by our group to evaluate ecotoxicity at sites contaminated with petrochemicals. This multidisciplinary project uses traditional analytical toxicology and population studies with pathology, genotoxicology, immunotoxicology, and physiological based monitoring with sophisticated statistical methods to determine the sensitivity of our techniques to evaluate ecotoxicity.
Sponsor: Air Force Office of Scientific Research
PIs: Robert Lochmiller, Charles Qualls, Jr., Karen McBee, and Nick Basta
Research Assistants: James Lish and Soochong Kim
Neurotoxicity of 1,3,5-Trinitrobenzene in Fischer 344 Rats
Trinitrobenzene (TNB) has been detected as an environmental contaminant associated with trinitrotoluene (TNT) manufacture and demilitarization. In previous studies, we have determined that TNB causes brain necrosis in rats. The purpose of this study is to characterize the brain lesion and to determine the time frame during which it develops and why it develops.
Sponsor: Health Effects Research Division, U.S. Army Environmental Hygiene Agency
PI: Charles Qualls, Jr.
Research Assistants: Soochong Kim and Eric L. Stair
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