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Biological melting curves for the “replicative form” of ΦX 174 DNA

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The effect of heating and quick cooling on the infectivity of partially purified ΦX 174 replicative form was examined. A sharp increase, up to 300 fold, in infectivity was observed over a range of 4–8° C. The biologicalT M (defined as half-maximal infectivity) shows a linear dependence on the logarithm of ionic strength. The G-C content of the replicative form, as calculated from a comparison of the biologicalT M values with opticalT M values obtained byMarmur andDoty onE. coli DNA, is 45% (theoretical value=43%). The results provide a simple biological assay for the replicative form; they also indicate a high specificity of our competent bacteria for the heated replicative form.

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  1. Doty, P., H. Boedtker, J. R. Fresco, R. Haselkorn andM. Litt: Secondary structure in ribonucleic acids. Proc. nat. Acad. Sci. (Wash.)45, 482 (1959).

  2. —,J. Marmur, J. Eigner andC. Schildkraut: Strand separation and specific recombination in deoxyribonucleic acids: Physical chemical studies. Proc. nat. Acad. Sci. (Wash.)46, 461 (1960).

  3. Evans, E. A., jr.,R. P. Mackal andL. Coleman: Infection of protoplasts with DNA from the virulent bacteriophage T 1. Fed. Proc.21, 456 (1962).

  4. Fiers, W., andR. L. Sinsheimer: The structure of the DNA of bacteriophage ΦX 174 II. Thermal inactivation. J. molec. Biol.5, 420 (1962).

  5. Geiduschek, E. P.: On the factors controlling the reversibility of DNA denaturation. J. molec. Biol.4, 467 (1962).

  6. Ginoza, W., andB. H. Zimm: Mechanism of inactivation of deoxyribonucleic acids by heat. Proc. nat. Acad. Sci. (Wash.)47, 639 (1961).

  7. Guild, W. R.: Evidence for intramolecular heterogeneity in pneumococcal DNA. J. molec. Biol.6, 214 (1963).

  8. Guthrie, G. D., andR. L. Sinsheimer: Infection of protoplasts ofEscherichia coli by subviral particles of bacteriophage ΦX 174. J. molec. Biol.2, 297 (1960).

  9. Hayashi, M., M. N. Hayashi andS. Spiegelman: Replicating form of a single-stranded DNA virus: Isolation and properties. Science140, 1313 (1963).

  10. Hofschneider, P. H.: Über ein infektiöses Desoxyribonucleinsäure-Agens aus dem Phagen ΦX 174. Z. Naturforsch.15b, 441 (1960).

  11. —: Studies on phage ΦX 174 infective DNA and its reduplication. Proc. V. Int. Congr. Biochem. 1961, Vol. I, p. 115. London: Pergamon Press 1963.

  12. Lehman, I. R.: The desoxyribonucleases ofEscherichia coli. I. Purification and properties of a phosphodiesterase. J. biol. Chem.235, 1479 (1960).

  13. Marmur, J.: A procedure for the isolation of desoxyribonucleic acid from microorganisms. J. molec. Biol.3, 208 (1961).

  14. —, andP. Doty: Determination of the base composition of desoxyribonucleic acid from its thermal denaturation temperature. J. molec. Biol.5, 109 (1962).

  15. —, andD. Lane: Strand separation and specific recombination in desoxyribonucleic acids: Biological studies. Proc. nat. Acad. Sci. (Wash.)46, 453 (1960).

  16. Meyer, F., R. P. Mackal, M. Tao andE. A. Evans jr.: Infectious deoxyribonucleic acid from lambda bacteriophage. J. biol. Chem.236, 1141 (1961).

  17. Roger, M., andR. D. Hotchkiss: Selective heat inactivation of pneumococcal transforming deoxyribonucleate. Proc. nat. Acad. Sci. (Wash.)47, 653 (1961).

  18. Sekiguchi, M., A. Taketo andY. Takagi: An infective deoxyribonucleic acid from bacteriophage ΦX 174. Biochim. biophys. Acta45, 199 (1960).

  19. Sinsheimer, R. L.: A single-stranded deoxyribonucleic acid from bacteriophage ΦX 174. J. molec. Biol.1, 43 (1959).

  20. —: Bacteriophage with single-stranded deoxyribonucleic acid. Fed. Proc.20, 661 (1961).

  21. —,B. Starman, C. Nagler andS. Guthrie: The process of infection with bacteriophage ΦX 174. I. Evidence for a “replicative form”. J. molec. Biol.4, 142 (1962).

  22. Wahl, R., J. Huppert andL. Emerique-Blum: Production de phages par des “protoplastes” bacteriens infectés par des préparations d' acide désoxyribonucleique. C. R. Acad. Sci. (Paris)250, 4227 (1960).

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Benzinger, R., Hofschneider, P.H. Biological melting curves for the “replicative form” of ΦX 174 DNA. Zeitschrift für Vererbungslehre 94, 316–321 (1963). https://doi.org/10.1007/BF00894775

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  • Ionic Strength
  • Linear Dependence
  • High Specificity
  • Sharp Increase
  • Biological Assay