Demonstration of Extrachromosomal Elements

  • LeRoy L. Voelker
  • Kevin Dybvig
Part of the Methods in Molecular Biology™ book series (MIMB, volume 104)


Mycoplasmas are parasites and pathogens of plants, insects, and animals, including humans. Although mycoplasmas are highly evolved parasites, they are not immune to being parasitized themselves. Within the class Mollicutes, extrachromosomal elements have been described for several genera, but although abundant in the spiroplasmas, are generally very rare (1,2). The plasmids identified so far are cryptic and have come from only two species, Mycoplasma mycoides subsp. mycoides and Spiroplasma citri (3). The best characterized are <2 kb in size, and contain genes only necessary for plasmid replication and maintenance. Sequence analysis indicates that they are related to a large family of Gram-positive bacterial plasmids that replicate by way of single-stranded DNA intermediates (4).


Microcentrifuge Tube Phage Particle Phage Genome Open Circular Extrachromosomal Element 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


  1. 10.
    Maniloff, J. (1992) Mycoplasma viruses, in Mycoplasmas: Molecular Biology and Pathogenesis (Maniloff, J., McElhaney, R. N., Finch, L. R., and Baseman, J. B., eds.), American Society for Microbiology, Washington, DC, pp. 41–59.Google Scholar
  2. 2.
    Dybvig, K. and Voelker, L. L. (1996) Molecular biology of mycoplasmas. Ann. Rev. Microbiol. 50, 25–57.CrossRefGoogle Scholar
  3. 3.
    Dybvig, K. (1990) Mycoplasmal genetics. Ann. Rev. Microbiol. 44, 81–104.CrossRefGoogle Scholar
  4. 4.
    Gruss, A. and Ehrlich, S. D. (1989) The family of highly interrelated single-stranded deoxyribonucleic acid plasmids. Microbiol. Rev. 53, 231–241.PubMedGoogle Scholar
  5. 5.
    Maniloff, J. (1988) Mycoplasma viruses. Crit. Rev. Microbiol. 15, 339–387.PubMedCrossRefGoogle Scholar
  6. 6.
    Ausubel, F. M., Brent, R., Kingston, R. E., Moore, D. D., Seidman, J. G., Smith, J. A., et al. (1994) Current Protocols in Molecular Biology. John Wiley, Inc., New York.Google Scholar
  7. 7.
    Beard, P., Morrow, J. F., and Berg, P. (1973) Cleavage of circular, superhelical simian virus 40 DNA to a linear duplex by S1 nuclease. J. Virol. 12, 1303–1313.PubMedGoogle Scholar
  8. 8.
    Voelker, L. L., Weaver, K. E., Ehle, L. J., and Washburn, L. R. (1995) Association of lysogenic bacteriophage MAV1 with virulence of Mycoplasma arthritidis. Infect. Immun. 63, 4016–4023.PubMedGoogle Scholar

Copyright information

© Humana Press Inc., Totowa, NJ 1998

Authors and Affiliations

  • LeRoy L. Voelker
    • 1
  • Kevin Dybvig
    • 1
  1. 1.Department of Comparative MedicineUniversity of Alabama at BirminghamBirmingham

Personalised recommendations