Agroterrorism - University of Georgia College of Veterinary Medicine

Georgia’s aquaculture industry is steadily expanding, with its greatest increaseoccurring in channel catfish production. Pond acreage for catfish farming hascontinued to grow every year. Other species being developed for aquacultureinclude striped and largemouth bass, yellow perch, and tilapia.In addition to Georgia’s developing food-fish industry, thereis an increasing interest in ornamental fish production,particularly koi, and cultured shellfish. It is estimatedthat aquaculture production in all countries will have toexpand at least twofold to meet world demand forfisheries products over the next 25 years.Continued commercial aquaculture success will depend on increased efficiency in resource use, innovativefarming methods, and a quality end product. Fish health is an essential issue at every level of fishproduction. As Georgia’s aquaculture industries continue to grow, research aimed at improving thehealth of aquatic animal species will help growers reduce production costs and improve profits.FishDNA Receptors and Innate Immunity in Catfish(II)novel approach to amplify adaptive immunityA in teleosts consists of the use of oligodeoxynucleotide(ODN) adjuvants. This model suggeststhat injections of bacterial DNA in conjunctionwith specific immunogen may significantly amplifyadaptive immune responses. We have previouslyidentified molecular pattern ligands in the form ofCpG, GpC and single base oligodeoxyguanosine 20-mers that bind to nonspecific cytotoxic cells (NCC).These ligands represent the experimental homologueof bacterial DNA and they specifically bind to DNAbinding proteins (DBPs) on NCC. In the presentVMES grant we identified three different molecularweight species (i.e. 14, 18 and 29 kDa) of DBPs onNCC. The 14 kDa protein was partially sequencedfrom tilapia NCC and is similar to histone core proteins.The 18 kDa molecule (from catfish NCC) ishistone-1 and the 29 kDa molecule is a novel proteinthat is similar (but not identical) to histone linkerproteins. The 29 kDa molecule was expressed as arecombinant protein and studies were carried out todetermine ODN binding, antimicrobial activity anda polyclonal was generated against this molecule.This recombinant (referred to as NCC antimicrobialprotein-1/ncamp-1) bound ODN; lysed Grampositive and Gram negative bacteria; and polyclonalanti-ncamp-1 bound NCC by Flow Cytometry analysis.These studies demonstrated that NCC expressmembrane DNA binding proteins and that in solubleform (ncamp-1) kills bacteria. This indicated thatNCC may directly participate in amplification ofinnate immune responses to bacteria by recognitionof DNA and elaboration of an antimicrobial protein.PI: Donald Evans (devans@vet.uga.edu)Identifying Virulence Mechanisms ofMycobacterium shottsii: An Emerging Disease ofFishStriped bass (Morone saxatilis) represent animportant commercial and recreational fishwith significant economic benefits to the boatingand tourism industries. In recent years there hasbeen heightened concern regarding the health ofstriped bass populations in eastern coastal waters ofthe United States. An epizootic of mycobacteriosiswas reported in the Chesapeake Bay which wascharacterized by lesion prevalence as high as 30-50%.Skin lesions were focal to multi-focal and ranged inseverity from small grayish-white depressions to largereddened, hyper-pigmented shallow lesions renderingthe fish unattractive and unpalatable. Histologicalexamination of skin lesions and internal organsrevealed granulomatous inflammatory responsesaccompanied by the presence of acid-fast bacilli. Ahigher prevalence of granulomatous lesions in visceralsamples than in skin indicated that many stripers areasymptomatic. Subsequent bacteriological studiesrevealed that infections were associated with a varietyof mycobacteria but were dominated by one uniquemycobacterial type (designated as M175), whichhad not been previously described. Based on priorstudies and field studies in progress by VirginiaInstitute of Marine Science (VIMS) investigators,12 Veterinary Medical Experiment Station