Logo of jbacterPermissionsJournals.ASM.orgJournalJB ArticleJournal InfoAuthorsReviewers
J Bacteriol. 1980 Sep; 143(3): 1194–1199.
PMCID: PMC294476

Covalently closed circular deoxyribonucleic acids in spiroplasmas.


Ten of twelve spiroplasma strains from different sources carried multiple covalently closed circular duplex deoxyribonucleic acid molecules, as shown by ethidium bromide-cesium chloride gradient centrifugation of cell lysates and examination of resulting bands by electron microscopy and agarose gel electrophoresis. Two to eight size classes per strain, comprising molecules of masses from 1 X 10(6) to 26 X 10(6), were detected. Several size classes of molecules were found in common in different spiroplasma strains. The amount of covalently closed circular deoxyribonucleic acid per strain was as much as 12% of total cellular deoxyribonucleic acid. The presence of sizes of the circular molecules appeared unrelated to either carriage or active production of known spiroplasma viruses, and it is tentatively concluded that they are plasmids rather than genomes or replicative forms of viruses.

Full text

Full text is available as a scanned copy of the original print version. Get a printable copy (PDF file) of the complete article (1008K), or click on a page image below to browse page by page. Links to PubMed are also available for Selected References.

Images in this article

Click on the image to see a larger version.

Selected References

These references are in PubMed. This may not be the complete list of references from this article.
  • Bauer W, Vinograd J. The interaction of closed circular DNA with intercalative dyes. I. The superhelix density of SV40 DNA in the presence and absence of dye. J Mol Biol. 1968 Apr 14;33(1):141–171. [PubMed]
  • Clowes RC. Molecular structure of bacterial plasmids. Bacteriol Rev. 1972 Sep;36(3):361–405. [PMC free article] [PubMed]
  • Cole RM, Mitchell WO, Garon CF. Spiroplasmavirus citri 3: propagation, purification, proteins, and nucleic acid. Science. 1977 Dec 23;198(4323):1262–1263. [PubMed]
  • Contente S, Dubnau D. Characterization of plasmid transformation in Bacillus subtilis: kinetic properties and the effect of DNA conformation. Mol Gen Genet. 1979 Jan 2;167(3):251–258. [PubMed]
  • Currier TC, Nester EW. Isolation of covalently closed circular DNA of high molecular weight from bacteria. Anal Biochem. 1976 Dec;76(2):431–441. [PubMed]
  • Das J, Maniloff J, Bhattacharjee SB. Dark and light repair in ultraviolet-irradiated Acholeplasma laidlawii. Biochim Biophys Acta. 1972 Jan 31;259(2):189–197. [PubMed]
  • Dugle DL, Dugle JR. Presence of two DNA populations in Mycoplasma laidlawii. Can J Microbiol. 1971 Mar;17(3):433–434. [PubMed]
  • Furness G, Cerone AM. Preparation of competent single-cell suspensions of Mycoplasma hominis tets and Mycoplasma salivarium tets for genetic transformation to tetracycline resistance by DNA extracted from Mycoplamsa hominis tetr. J Infect Dis. 1979 Apr;139(4):444–451. [PubMed]
  • Johnson PH, Grossman LI. Electrophoresis of DNA in agarose gels. Optimizing separations of conformational isomers of double- and single-stranded DNAs. Biochemistry. 1977 Sep 20;16(19):4217–4225. [PubMed]
  • Lang D. Molecular weights of coliphages and coliphage DNA. 3. Contour length and molecular weight of DNA from bacteriophages T4, T5 and T7, and from bovine papilloma virus. J Mol Biol. 1970 Dec 28;54(3):557–565. [PubMed]
  • LeBlanc DJ, Hassell FP. Transformation of Streptococcus sanguis Challis by plasmid deoxyribonucleic acid from Streptococcus faecalis. J Bacteriol. 1976 Oct;128(1):347–355. [PMC free article] [PubMed]
  • Liss A, Maniloff J. Transfection mediated by Mycoplasmatales viral DNA. Proc Natl Acad Sci U S A. 1972 Nov;69(11):3423–3427. [PMC free article] [PubMed]
  • Macrina FL, Kopecko DJ, Jones KR, Ayers DJ, McCowen SM. A multiple plasmid-containing Escherichia coli strain: convenient source of size reference plasmid molecules. Plasmid. 1978 Jun;1(3):417–420. [PubMed]
  • Maniloff J, Das J, Christensen JR. Viruses of mycoplasmas and spiroplasmas. Adv Virus Res. 1977;21:343–380. [PubMed]
  • Reddy VB, Thimmappaya B, Dhar R, Subramanian KN, Zain BS, Pan J, Ghosh PK, Celma ML, Weissman SM. The genome of simian virus 40. Science. 1978 May 5;200(4341):494–502. [PubMed]
  • Sanger F, Coulson AR, Friedmann T, Air GM, Barrell BG, Brown NL, Fiddes JC, Hutchison CA, 3rd, Slocombe PM, Smith M. The nucleotide sequence of bacteriophage phiX174. J Mol Biol. 1978 Oct 25;125(2):225–246. [PubMed]
  • Tully JG, Whitcomb RF, Clark HF, Williamson DL. Pathogenic mycoplasmas: cultivation and vertebrate pathogenicity of a new spiroplasma. Science. 1977 Mar 4;195(4281):892–894. [PubMed]
  • Williamson DL, Whitcomb RF. Plant mycoplasmas: a cultivable spiroplasma causes corn stunt disease. Science. 1975 Jun 6;188(4192):1018–1020. [PubMed]
  • Zouzias D, Mazaitis AJ, Simberkoff M, Rush M. Extrachromosomal DNA of Mycoplasma hominis. Biochim Biophys Acta. 1973 Jul 13;312(3):484–491. [PubMed]

Articles from Journal of Bacteriology are provided here courtesy of American Society for Microbiology (ASM)


Save items

Related citations in PubMed

See reviews...See all...

Cited by other articles in PMC

See all...


  • PubMed
    PubMed citations for these articles

Recent Activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...