1887

Abstract

The evolution of Fusarium graminearum A3/5 grown in a glucose-limited chemostat at a dilution rate of 0.05 h(doubling time of 13.9 h) was followed for 957 h or 69 generations. Periodic selection of advantageous mutants was monitored in the culture by determining increases and decreases in the concentration of cycloheximide-resistant macroconidia in the population. Six peaks in the concentration of cycloheximide-resistant macroconidia were observed representing five adaptive changes in the population; on average, an adaptive change occurred once every 148±22 h (mean±). The selection coefficient of strains present at the start of each increase in the concentration of cycloheximide-resistant macroconidia (i.e. after the establishment of a new advantageous strain) was determined relative to A3/5 and was found to increase progressively with time. When grown at a dilution rate of 0.05 h, the strain (A28-S) isolated from the last adaptive peak had a selection coefficient of 0.023 hrelative to A3/5, but A28-S lost its selective advantage when grown at a dilution rate of about 0.11 hand was at a selective disadvantage when grown at a dilution rate higher than 0.11 h. The value (12±5 μM) for uptake of glucose by A28-S was significantly lower than that for A3/5. The spontaneous mutation rate from cycloheximide sensitivity to cycloheximide resistance was estimated to be 1.8 (±0.2) × 10hor 2.5 × 10generation. The culture initially contained about 1 × 10macroconidia mlbut this decreased with time until, at about 800 h, the culture contained only about 1 × 10macroconidia ml. No highly branched (colonial) mutants were observed in glucose-limited cultures at dilution rates of 0.05 heven though the evolution of the population was followed for a further 1345 h in a second chemostat, making a total evolutionary period of 2207 h or 159 generations.

Loading

Article metrics loading...

/content/journal/micro/10.1099/13500872-140-11-3023
1994-11-01
2021-08-01
Loading full text...

Full text loading...

/deliver/fulltext/micro/140/11/mic-140-11-3023.html?itemId=/content/journal/micro/10.1099/13500872-140-11-3023&mimeType=html&fmt=ahah

References

  1. Adams J., Paquin C., Oeller P.W., Lee L.W. Physiological characterization of adaptive clones in evolving populations of the yeast, Saccharomyces cerevisiae. Genetics 1985; 110:173–185
    [Google Scholar]
  2. Carter B.L.A., Bull A.T. Studies of fungal growth and intermediary carbon metabolism under steady and non-steady state conditions. Biotechnol Bioeng 1969; 11:785–804
    [Google Scholar]
  3. Dykhuizen D.E., Hartl D. Evolution of competitive ability in Escherichia coli. Evolution 1981; 35:581–594
    [Google Scholar]
  4. Dykhuizen D.E., Hartl D.L. Selection in chemostats. Microbiol Rev 1983; 47:150–168
    [Google Scholar]
  5. Fincham J.R., Day P.R., Radford A. Fungal Genetics 1979 London: Blackwell Scientific Publications;
    [Google Scholar]
  6. Helling R.B., Vargas C.N., Adams J. Evolution of Escherichia coli during growth in a constant environment. Genetics 1987; 116:349–358
    [Google Scholar]
  7. James T.W. Continuous culture of micro-organisms. Ann Rev Microbiol 1961; 15:27–46
    [Google Scholar]
  8. Miller J.J. Cultural and taxonomic studies on certain Fusaria. I. Mutations in culture. Can J Res 24 1946; C):188–212
    [Google Scholar]
  9. Monod J. Recherches sur la Croissance des Cultures Bacteriennes 1942 Paris: Hermann et Cie;
    [Google Scholar]
  10. Moser H. The dynamics of bacterial populations maintained in the chemostat 1958 Washington, DC: Carnegie Institute of Washington, Publication 61;
    [Google Scholar]
  11. Novick A., Szilard L. Description of the chemostat. Science 1950a; 112:715–716
    [Google Scholar]
  12. Novick A., Szilard L. Experiments with the chemostat on spontaneous mutation of bacteria. Proc Natl Acad Sei USA 1950b; 36:708–719
    [Google Scholar]
  13. Paquin C., Adams J. Frequency of fixation of adaptive mutations is higher in evolving diploid than haploid yeast populations. Nature 1983a; 302:495–500
    [Google Scholar]
  14. Paquin C., Adams J. Relative fitness can decrease in evolving asexual populations of Saccharomyces cerevisiae. Nature 1983b; 306:368–371
    [Google Scholar]
  15. Powell E.O. Criteria for the growth of contaminants and mutants in continuous culture. J Gen Microbiol 1958; 18:259–268
    [Google Scholar]
  16. Righelato R.C. Selection of strains of Penicillium chrysogenum with reduced penicillin yields in continuous cultures. J Appl Chem Biotecbnol 1976; 26:153–159
    [Google Scholar]
  17. Rothschild H., Germershausen J., Suskind S.R. Biochemical genetic studies of cycloheximide resistance in Neurospora crassa. Biochem Genet 1975; 13:283–300
    [Google Scholar]
  18. Trinci A.P.J. A study of the kinetics of hyphal extension and branch initiation of fungal mycelia. J Gen Microbiol 1974; 81:225–236
    [Google Scholar]
  19. Trinci A.P.J. Myco -protein -a twenty-year overnight success story. Mycol Res 1992; 96:1–13
    [Google Scholar]
  20. Van Uden N. Kinetics of nutrient-limited growth. Ann Rep Microbiol 1969; 23:473–486
    [Google Scholar]
  21. Vogel H.J. A convenient growth medium for Neurospora (Medium N). Microb Genet Bull 1956; 13:42–44
    [Google Scholar]
  22. Vomvoyanni V. Multigenic control of ribosomal properties associated with cycloheximide sensitivity in Neurospora crassa. Nature 1974; 248:508–510
    [Google Scholar]
  23. Walmsley A.R., Lowe A.G. Multifit: a flexible nonlinear least squares regression program in basic. Comp Methods Progr Biomed 1985; 21:113–118
    [Google Scholar]
  24. Wiebe M.G., Trinci A.P.J. Dilution rate as a determinant of mycelial morphology in continuous culture. Biotecbnol Bioeng 1991; 38:75–81
    [Google Scholar]
  25. Wiebe M.G., Trinci A.P.J., Cunliffe B., Robson G.D., Oliver S.G. Appearance of morphological (colonial) mutants in glucose-limited, continuous flow cultures of Fusarium graminearum A3/5. Mycol Res 1991; 95:1284–1288
    [Google Scholar]
  26. Wiebe M.G., Robson G.D., Cunliffe B., Trinci A.P.J., Oliver S.G. Nutrient-dependent selection of morphological mutants of Fusarium graminearum A3/5 isolated from long-term continuous flow cultures. Biotecbnol Bioeng 1992; 40:1181–1189
    [Google Scholar]
  27. Wiebe M.G., Robson G.D., Cunliffe B., Oliver S.G., Trinci A.P.J. Periodic selection in longterm continuous-flow cultures of the filamentous fungus Fusarium graminearum. J Gen Microbiol 1993; 139:2811–2817
    [Google Scholar]
  28. Withers J.M., Wiebe M.G., Robson G.D., Trinci A.P.J. Development of morphological heterogenicity in glucose-limited chemostat cultures of Aspergillus oryzae. Mycol Res 1994; 98:95–100
    [Google Scholar]
http://instance.metastore.ingenta.com/content/journal/micro/10.1099/13500872-140-11-3023
Loading
/content/journal/micro/10.1099/13500872-140-11-3023
Loading

Data & Media loading...

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error