Animal and Food Sciences | Faculty
John Dohms, Ph.D.
- Ph.D., Veterinary Microbiology, Ohio State University, 1977
- B.S., M.S. Biology, Bowling Green State University, 1970/1972
- ANSC 332 - Introduction to Animal Disease
- ANSC 367 - Sophomore Seminar
- Avian Mycoplasmas. The mycoplasmas are an unusual group of prokaryotic microorganisms that infect a wide variety of plants, insects, and vertebrates. They are among the smallest recorded cells with genomes approaching the theoretical minimal genes required for cell survival. Most mycoplasmas are commensuals but a fair number of species are pathogens. Among agriculturally important animals, pathogenic mycoplasmas are found in poultry, goats, sheep, cattle, and pigs causing significant losses. Among the avian mycoplasma pathogens, Mycoplasma gallisepticum (MG) causes respiratory infections in chickens and turkeys and is a serious global problem. In particular when MG infected birds are also infected with other viruses or bacteria, high morbidity and mortality can result. Mycoplasma synoviae (MS), specific for chickens and turkeys, causes respiratory infection and also synovitis resulting in leg problems. M. meleagridis (MM) and M. iowae (MI) cause respiratory infections in turkeys. Numerous nonpathogenic mycoplasmas have been isolated. MG, MS, and MM can be transmitted horizontally and vertically to progeny. Therefore, outbreaks in breeder flocks are particularly devastating resulting in depopulation and eradication of these flocks and their offspring. Our research focus has been on MG using both a basic and applied approaches. One of the fundamental questions about MG infections is that they produce chronic infections despite a vigorous host immune response. Once infected, chickens may shed the organism for life. We have been particularly interested in two questions. How does this organism initially colonize the host, and secondly, how does MG evade the immune response?
- Colonization. Two pathogenic human mycoplasmas M. pneumoniae and M. genitalium produce respiratory and urinogenital infections respectively and are closely related genetically and have been extensively studied. These organisms are flask shaped and possess an attachment organelle called a bleb. Situated on the bleb are specific attachment proteins called cytadhesins that bind to human epithelial cell receptors. Additional cytadhesin accessory genes also support the bleb structure and orient the cytadhesins onto the bleb. These mycoplasmas can move by gliding motility and are thought to use this process to penetrate the mucous sheet in the respiratory tract and attach to the ciliated epithelium. MG is also flask shaped and moves my gliding motility. In 1994 we became interested in determining if MG used similar mechanisms and proteins to attach and colonize chickens and turkeys. In collaboration with Dr. Calvin Keeler, we used published sequence of the human mycoplasmas principal cytadhesins to find regions of homology between these sequences. Designing primers from homologous regions allowed us to amplify a 234 bp region of MG, which showed homology to the shared sequence of the human mycoplasmas (dohms et al, 1994).
Peer Reviewed Publications
Saif, Y. M., and J. E. Dohms. Isolation and characterization of immunoglobulins G and M of the Turkey. Avian Dis. 20:79-95. 1976.
Dohms, J. E., Y. M. Saif, and J. E. Pitts. Isolation of turkey immunoglobulin A. Avian Dis. 22:151-156. 1978.
Dohms, J. E., Y. M. Saif, and W. B. Bacon. Metabolism and passive transfer of immunoglobulins in the turkey hen. Am. J. Vet. Res. 39:1472 1481. 1978.
Dohms, J. E., Y. M. Saif, and W. B. Bacon. Studies on metabolism and concentrations of immunoglobulin G in the newly hatched turkey poult. Am. J. Vet. Res. 39:1466-1471. 1978.
Dohms, J. E., K. P. Lee, and J. K. Rosenberger. Plasma cell changes in the gland of Harder following infectious bursal disease virus infection of the chicken. Avian Dis. 25:683-695. 1981.
Dohms, J. E., and S. S. Cloud. Susceptibility of broiler chickens to Clostridium botulinum type C toxin. Avian Dis. 26:89-96. 1982.
Dohms, J. E., P. H. Allen, and J. K. Rosenberger. Cases of type C botulism in broiler chickens. Avian Dis. 26:204-210. 1982.
Dohms, J. E., P. H. Allen, and S. S. Cloud. The immunization of broiler chickens against type C botulism. Avian Dis. 26:340-345. 1982.
Dohms, J. E., and Y. M. Saif. Criteria for evaluating immunosuppression. Avian Dis. 28:305-310. 1984.
Greenfield, C. L., J. E. Dohms, and R. R. Dietert. Infectious bursal disease virus infection in the quail-chicken hybrid. Avian Dis. 30:536-542. 1986.
Dohms, J. E., K. P. Lee, J. K. Rosenberger and A. L. Metz. Plasma cell quantitation in the gland of Harder during infectious bursal disease virus infection of 3-week-old broiler chickens. Avian Dis. 32:624-631. 1988.
Dohms, J. E., and J. S. Jaeger. The effect of infectious bursal disease virus infection on local and systemic antibody responses following infection of 3-week-old broiler chickens. Avian Dis. 32:632-640. 1988.
Sharma, J. M., J. E. Dohms, and A. L. Metz. Comparative pathogenesis of serotype 1 and variant serotype 1 isolates of infectious bursal disease virus and the effect of these viruses on humoral and cellular immune competence of specific pathogen free chickens. Avian Dis. 33:112-124. 1989.
Gelb, J., Jr., J. K. Rosenberger, P. A. Fries, S. S. Cloud, E. M. Odor, J. E. Dohms, and J. S. Jaeger. Protection afforded infectious bronchitis virus-vaccinated sentinel chickens raised in a commercial environment. Avian Dis. 33:764-769. 1989.
Dohms, J. E. Mechanisms of immunosuppression. Vet. Immunol. and Immunopath. 30:19-30. 1991.
Dohms, J. E., and A. Metz. Stress-mechanisms of immunosuppression. Vet. Immunol. and Immunopath. 30:89-109. 1991.
Dohms, J. E., L. L. Hnatow, P. Whetzel, R. Morgan, and C. L. Keeler, Jr. Identification of the putative cytadhesin gene of Mycoplasma gallisepticum and its use as a diagnostic DNA probe. Avian Dis. 37: 380-388. 1993.
Sharma, J. M., J. Dohms, M. Walser, and D. B. Snyder. Presence of lesions without virus replication in the thymus of chickens exposed to infectious bursal disease virus. Avian Dis. 37:741-748. 1993.
Keeler, C. L., Jr., L. Hnatow, P. L. Whetzel and J. E. Dohms. Cloning and characterization of a putative cytadhesin gene (mgc1) from Mycoplasma gallisepticum. Infect. Immun. 64:1541-1547. 1996.
Hnatow, L. L., C. L. Keeler, Jr., L. Tessmer, K. Czymmek, and J. E. Dohms. Characterization of MGC2, a Mycoplasma gallisepicum cytadhesin with homology to Mycoplasma pneumoniae 30-kilodalton protein P30 and M. genitalium P32. Infect. Immun. 66:3436-3442.1998.
Book Chapters
Dohms, J. E. Laboratory investigations of botulism in poultry. In: Avian botulism: an international perspective. M. W. Eklund and V. R. Dowell, Jr. eds. U.S.-Japan Joint Panel on Toxic Microorganisms. Charles C. Thomas, Springfield, Ill. pp: 245 - 314. 1987.
Dohms, J. E. Botulism. In: Diseases of Poultry. B. W. Calnek, J. J. Barnes, C. W. Beard, W. M. Reid, and H. W. Yoder, Jr. ads. 9th Edition Iowa State University Press, Ames, Iowa, pp. 271 - 276. 1991.
Dohms, J. E. Biotechnology and the Control of Disease. In: Biotechnology, Science and Socioeconomic Issues. L. E. Sterling, C. K. Halbrendt, S. L. Kitto eds. Kendall/Hunt Publishing Co. Dubuque, Iowa. pp: 31-44. 1992. (teaching)
Dohms, J. E. Avian Botulism. In: The Merck Veterinary Manual. Eighth edition. Merck Co., Inc., Rahway, NJ. pp: 1969-1970. 1998.
Dohms, J. E. Botulism. In: Diseases of Poultry. B. W. Calnek, J. J. Barnes, C. W. Beard, W. M. Reid, and H. W. Yoder, Jr. ads. 10th Edition Iowa State University Press, Ames, Iowa, pp. 268-273. 1997.
Dohms, J. E. Botulism In: Diseases of Poultry, Y. M. Saif, J. J. Barnes, A. M. Fadly, J. R. Glisson, L. R. McDougald, and D. E. Swaine. eds. 11th Edition. Iowa State University Press, Ames, Iowa, in press.
Proceedings and Abstracts:
Dohms, J. E. The altered immune system as it affects respiratory tract infections. Proc. 14th Natl. Meeting on Poultry Health and Condemnations. 1979
Dohms, J. E. Clostridium associated toxemia in broilers. Proc. 13th Natl. Meeting on Poultry Health and Condemnations. 1978.
Dohms, J. E., and P. H. Allen. Studies on avian botulism. Proc. 51st Northeastern Conference on Avian Diseases. 1979.
Dohms, J. E., K. P. Lee, and J. K. Rosenberger. Cellular changes in the Harderian gland of chickens infected by infectious bursal disease virus. Proc. 52nd Northeastern Conference on Avian Diseases. 1980.
Dohms, J. E., K. P. Lee, and J. K. Rosenberger. Plasma cell changes in the fowl gland of Harder following infectious bursal disease virus (IBDV) infection. Absts. 61st Annual Meeting of the Conference of Research Workers in animal diseases. 1980
Dohms, J. E., K. P. Lee, S. S. Cloud, and J. K. Rosenberger. Plasma cell changes in the fowl gland of Harder following infectious bursal disease virus infection at three weeks of age. Proc. 53rd Northeastern Conference on Avian Diseases. 1981.
Dohms, J. E., and L. Miller. Gas liquid chromatography as a means of avian mycoplasma identification. Poultry Sci. 63. Suppl. 1:93. 1984.
Jaeger, J. S., and J. E. Dohms. The influence of infectious bursal disease virus infection on antibody responses in broiler chickens. Proc. 57th Northeastern Conference on Avian Diseases. 1985.
Dohms, J. E., and C. C. Greenfield. The influence of infectious bursal disease virus on immune responses to Newcastle disease virus in broiler chickens. Proc. 57th Northeastern Conference on Avian Diseases. 1985.
Dohms, J. E., and J. S. Jaeger. Effects of infectious bursal disease virus on local and systemic antibody responses in broiler chickens. Abst. 66th Meeting Conference Research Workers in Animal Diseases. 1985.
Rosenberger, J. K., S. S. Cloud, J. Gelb, E. Odor, and J. E. Dohms. Sentinel bird survey of Delmarva broiler flocks. Proc. 12th Natl. Meeting Poultry Health and Condemnations. 1985.
Dohms, J. E., and J. S. Jaeger. Effect of infectious bursal disease virus variants on immunological responsiveness of chickens. Proc. 58th Northeastern Conference on Avian Diseases. 1986.
Dohms, J. E., and J. S. Jaeger. Antibody responses to Mycoplasma gallisepticum and Mycoplasma synoviae proteins. Proc. 123rd Annual Meeting AVMA. 1986.
Dohms, J. E., R. W. Morgan, and L. Zeimer. Construction and partial characterization of a Mycoplasma gallisepticum (MG) genomic library. Proc. 59th Northeastern Conference Avian Diseases. 1987.
Carr, Y. M., J. E. Dohms, W. W. Saylor, and A. L. Metz. Effect of infectious bursal disease virus (IBDV) pathotypes on iron metabolism of the chicken. Proc. 59th Northeastern Conference on Avian Diseases. 1987.
Saylor, W. W., J. E. Dohms, A. L. Metz, and M. Carr. Responses of plasma and tissue iron and zinc to three strains of infectious bursal disease virus (IBDV) in chickens. Poultry Sci., 66 (Supplement): 173. 1987.
Metz, A. L., J. E. Dohms, and M. Y. Carr. The immunotoxicity of corticosterone in chickens. Proc. 59th Northeastern Conference on Avian Diseases. 1987.
Sarma, G., S. Kumar, and J. E. Dohms. Evaluation of an experimental Mycoplasma gallisepticum bacterin in chickens and turkeys by serological and challenge tests. Proc. 59th Northeastern Conference on Avian Diseases. 1987.
Dohms, J. E., M. Y. Carr, W. W. Saylor, and A. L. Metz. Changes in iron metabolism following infection by different infectious bursal disease (IBDV) pathotypes. Proc. 68th Conference of Research Workers in Animal Diseases. 1987.
Rosenberger, J. K., S. S. Cloud, A. Metz, E. Odor, J. Gelb, J. E. Dohms, and R. L. Witter. 1987 Sentinel bird study of Delmarva poultry. Proc. 22nd National meeting on Poultry Health and Condemnations. 1987.
Saif, Y. M., J. E. Dohms, and J. M. Sharma. Immunosuppression induced by infectious bursal disease virus. XI Pan Amer. Veterinary Congress, Lima, Peru. 1988.
Jaeger, J. S., and J. E. Dohms. Kinetics of antibody responses in chickens infected with variant infectious bursal disease virus. Proc. 61st Northeastern Conference on Avian Diseases. Blacksburg, Va. June 11-13. 1989.
Moran, J. S., and J. E. Dohms.The effect of variant infectious bursal disease virus (IBDV) on the susceptibility of broiler chickens to E. coli. Proc. 61st Northeastern Conference on Avian Diseases. Blacksburg, VA. June 11-13. 1989.
Anderson, A., R. Morgan, and J. E. Dohms. Identification of genes of Marek's disease virus by expression vector cloning in the bacteriophage Lamda gt11. Proc. 61st Northeastern Conference on Avian Diseases. Blacksburg, VA. June 11-13. 1989.
Dohms, J. E. Defining and dealing with immunosuppression. Proc. 24th National Meeting on Poultry Health and Condemnation. Ocean City, Maryland. October 19-20, 1989.
Dohms, J. E. , C. L. Keeler, L. L. Hnatow, R. W. Morgan, and P. L. Whetzel. Cloning of the Mycplasma gallisepticum cytadhesin gene. 72nd Annual meeting of the Conference of Research Workers on Animal Diseases, Chicago, IL. November 11-12. 1991.
Hnatow, L., P. L. Whetzel, R. W. Morgan, C. L. Keeler, and J. E. Dohms. Studies with a Mycoplasma gallisepticum cyt adhesin gene probe. Abstracts of the 64th Northeastern Conference on Avian Diseases. pg. 3. Pennsylvania State University, Universtity Park, PA. June 17-19. 1992.
Dohms, J. E., C. L. Keeler, Jr., L. L. Hnatow, R. W. Morgan, and P.L. Whetzel. Identification, cloning and sequencing of the putative cytadhesin gene of Mycoplasma gallisepticum. Annual meeting of the American Veterinary Medical Association. August 1-5, Boston, MA. 1992.
Dohms, J. E., L. L. Hnatow, P. Whetzel, and C. L. Keeler, Jr. Cloning and sequence analysis of the putative Mycoplasma gallisepticum cytadhesin gene. Do pathogenic human and avian mycoplasma use a similar cytadhesin? 1993 Philadelphia Infection and Immunity Forum. Eastern Pennsylvania Branch American Society for Microbiology. Philadelphia, PA, April 14, 1993.
Hnatow, L. L., C. L. Keeler, Jr., T. Whetzel, and J. E. Dohms. Cloning and complete sequence analysis of the putative MG cytadhesin gene. Proc. 65th Northeastern Conferance on Avian Diseases. p. 31. Univ. Delaware, June 9-11, 1993.
Dohms, J.E., C. L. Keeler, Jr., L. L. Hnatow, P. L. Whetzel, L. L. Tessmer, and B. F. Kingham. Studies of the molecular pathogenesis of Mycoplasma gallisepticum. Proc. 67th Northeastern Conferance on Avian Diseases. p. 34. Mystic Conn., June 12-14, 1995.
Dohms, J. E., C. C. Keeler, Jr., L. Hnatow, and B. F. Kingham. Mycoplasma gallisepticum diagnosis using nucleic acid sequence from putative cytadhesin genes. 132nd meeting of the American Veterinary Medical Association. July, 8-12, Pittsburg, PA, 1995.
Hnatow, L. L., C. L. Keeler, Jr., L. L. Tessmer, and J. E. Dohms. Characterization of a second Mycoplasma gallisepticum cytadhesin. Proc. 68th Northeastern Conference on Avian Diseases, p. 16. Penn State Univ., State College, PA, June 10-12, 1996.
Whetzel, P. L., and J. E. Dohms. Random and site-directed mutagenesis of Mycoplasma gallisepticum.. Proc. 68th Northeastern Conference on Avian Diseases, p. 16. Penn State Univ., State College, PA, June 10-12, 1996.
Hnatow, L. L., and J. E. Dohms. Functional characterization of Mycoplasma gallisepticum cytadhesins. Proc. 69th Northeastern Conference on Avian Diseases, p.6. Cornell Univ., Ithaca, NY, June 11-13, 1997.
Whetzel, P. L., and J. E. Dohms. Searching for attenuated Mycoplasma gallisepticum strains from a transposon generated random mutant library. Proc. 69th Northeastern Conferance on Avian Diseases, p.6. Cornell Univ., Ithaca, NY, June 11-13, 1997.
J. E. Dohms. The local and systemic antibody response of chickens to two Mycoplasma gallisepticum cytadhesins. Proc. American Veterinary Medical Association Meetings. Baltimore, MD. July 28, 1998.
Whetzel, P. L., and J. E. Dohms. Use of transposon mutagenesis to identify Mycoplasma gallisepticum virulence factors. 71st Northeastern Conference on Avian Diseases. Blacksburg, VA, 1999.
Dohms, J. E. Recent Mycoplasma gallisepticum outbreaks on Delmarva. 72nd Northeastern Conference on Avian Diseases. Uiversity of Delaware, June 14-15. 2000. pp: 4-5.
Invited Seminars/Short Courses:
Dohms, J. E. Infectious bursal disease impact on broiler chickens. U.S.D.A. Avian Disease and Oncology Laboratory, East Lansing MI. 1986.
Dohms, J. E. Applications of biotechnology to mycoplasma control. Cargill, Inc., Minneapolis, MN. 1986.
Dohms, J. E. Defining immunosuppression. Eli Lilly, Greensport IN. 1989.
Dohms, J. E. Mechanisms of immunosuppression. Poultry Immunosuppressive Diseases Symposium. 41st North Central Avian Diseases Conference, Columbus, Ohio. September 16-17, 1990.
Dohms, J. E. Stress - mechanisms of immunosuppression. Poultry Immunosuppressive Diseases Symposium. 41st North Central Avian Diseases Conference, Columbus, Ohio. September 16-17, 1990.
Dohms, J. E. Acute IBDV and E. coli infections in chickens - does the host response cause disease? MSD Ag-Vet Poultry Seminar. Salsbury, Maryland, 1991.
Dohms, J. E. Jornada sobre immunosupresion e inmunodiagnostico en enfermedades aviares. Facultad ciencias veterinarias y pecuarias. Universidad de chile. Santiago, Chile. July 24, 1992. This was a short course taught at the Veterinary School on Infectious bursal disease and its control.
Dohms, J. E. Characterization of a putative Mycoplasma gallisepticum cytadhesin. Department of Pathobiology, University of Connecticut, Storrs, Connecticut, October 8, 1992.
Dohms, J. E. Applications of biotechnology to disease control. Biotechnology Workshop. University of Delaware, Newark, DE, Jan. 21, 1993.
Dohms, J. E. Clostridial diseases of poultry. National broiler council meeting, Washington D.C., October 19, 1993.
Dohms, J. E. Mycoplasma gallisepticum update. 2000 Delmarva Breeder, Hatchery, and Growout Conference. Delmar MD, Sept. 13, 2000.pp: 1-3.
Popular Press:
Dohms, J. E. Clostridium-associated toxemia in broilers. Poultry digest 38(444): 106-108. 1979.
Dohms, J. E. Botulism vaccine works on chicks. Broiler Industry. 42(1):46. 1979.
Dohms, J. E. Clostridium-associated toxemia in broilers. Australian Poultry World. August, 1979.
Dohms, J. E. Toxemia asociada a clostridio en pollus de asar. Industria avicola 26(8): 40-42. 1979.
Dohms, J. E., and S. Kumar. Coarse Droplet Spray Vaccination –why does it work-even in day old chicks? Vineland Update. 1984.
Dohms, J. E. At the University of Delaware, Agricultural research being whittled away? Sunday Forum, Wilmington News Journal, Nov. 26, 1989.
Dohms, J. E. African white water - Running the Big Z. Out and About Magazine. April 1994. pp 22-26.
Dohms, J. E. River Wild, Chiles Rio Futaleafu offers world-class white water and spectacular scenery in Patagonia Andes. Out and About Magazine, June, 1995:8 (4):20-24.
U.S. Patent:
Keeler and Dohms. Gene encoding cytadhesin protein of Mycoplasma gallisepticum and its use. UD 92-05, US Patent 5,378,820, Jan 3, 1995.
External Funding and Grants 1983 - Present:
Immune mechanisms in the control and diagnosis of important poultry diseases. USDA federal regional research project. Funding shared with J. Gelb and J.K. Rosenberger. 1983-1991. $20,000/year
Role of Nitrates as a Cause of Lymphoid Tissue Pathology in the Fowl. 1987-1989, University of Delaware Research Foundation with W. Saylor and A. L. Metz. $12,000
A Novel Approach to Increasing Immunogenicity of Inactivated IBDV Vaccines. 1988-1989, Ross Laboratories. $6,800
Efficiency of New Aryl-Fluro Quinolones in Control of Selected Poultry Respiratory Pathogens, 1988-1989, Abbott Laboratories. $22,150
Evaluation of Immunosuppression by Antigenic Variants of Infectious Bursal Disease Virus, 1987-1990, Southeastern Poultry Egg Association. $40,500
Interactions between IBDV, IBV, and E. coli in a respiratory disease complex in chickens. USDA federal regional research project. Funding shared with J. Gelb, C. Keeler, C. Pope, and J. K. Rosenberger. 1991-1993. $20,000/year
Characterization of a Putative Mycoplasma gallisepticum cytadhesin. 1993-1995, National Research Initiative, U.S.D.A. $110,000
Evaluation of attenuated Mycoplasma gallisepticum strains as vaccines for the prevention of mycoplasmosis in chickens. 1994. Immunogenetics, Inc. Vineland Laboratories. $8,894.
Characterization of Mycoplasma gallisepticum transposon mutants. College of Agriculture Competitive Grants Program. 1997. $15,000
Use of Recombinant Mycoplasma gallisepticum cytadhesin proteins as vaccines. U.S. Poultry and Egg Association. 1997-1998. $29,877
Defining Patterns of Mycoplasma gallisepticum Gene Expression in Host Tissues. USDA-NRI. 1999-2001. $49,543
Development of Methods to Separate Mycoplasma gallisepticum Field Strains from Non Pathogenic Avian Mycoplasmas. U.S. Poultry & Egg Association. 2000-2002. $25,416
