1887

Abstract

By monitoring increases and decreases in the proportion of cycloheximide-resistant macroconidia, periodic selection was observed in populations of the filamentous fungus , grown in glucose-limited chemostat cultures. The results indicated that periodic selection of advantageous mutants of occurred at intervals of about 124 h at both high ( = 0·19 h, approximately 34 generations) and low ( = 0·06 h, approximately 11 generations) dilution rates. Several ‘adaptive’ peaks (each indicating the appearance of an advantageous mutation) were observed before morphological (highly branched) mutants appeared in the populations; these mutants have previously been observed to have a selective advantage over the parental strain. At intervals, macroconidia harvested from the chemostat were used to inoculate plates of non-antibiotic-containing agar medium, and it was possible to monitor periodic selection in the original chemostat culture using second generation macroconidia harvested from these cultures. The proportion of cycloheximide-, potassium chlorate-, and -fluoro--phenylalanine-resistant macroconidia in these second generation macroconidia changed in a pattern similar to that observed when monitoring the proportion of cycloheximide-resistant macroconidia in the first generation population harvested directly from the chemostat. The experiments demonstrated that populations of filamentous fungi are heterogeneous and that much of this heterogeneity may already be present at the end of batch growth, i.e. before the onset of continuous cultivation.

Loading

Article metrics loading...

/content/journal/micro/10.1099/00221287-139-11-2811
1993-11-01
2021-05-07
Loading full text...

Full text loading...

/deliver/fulltext/micro/139/11/mic-139-11-2811.html?itemId=/content/journal/micro/10.1099/00221287-139-11-2811&mimeType=html&fmt=ahah

References

  1. Adams J., Oeller P. W. 1986; Structure of evolving populations of Saccharomyces cerevisiae: adaptive changes are frequently associated with sequence alterations involving mobile elements belonging to the Ty family. Proceedings of the National Academy of Sciences of the United States of America 837124–7127
    [Google Scholar]
  2. Charlesworth B. 1983; Adaptive evolution in the laboratory. Nature; London: 302479–480
    [Google Scholar]
  3. Dykhuizen D., Hartl D. 1981; Evolution of competitive ability in Escherichia coli. Evolution 35:581–594
    [Google Scholar]
  4. Dyxhuizen D. E., Hartl D. L. 1983; Selection in chemostats. Microbiology Reviews 47:150–168
    [Google Scholar]
  5. Helling R. B., Vargas C. N., Adams J. 1987; Evolution of Escherichia coli during growth in a constant environment. Genetics 116:349–358
    [Google Scholar]
  6. Hsu K. S. 1963; The genetic basis of actidione resistance in Neurospora. Journal of General Microbiology 32:341–347
    [Google Scholar]
  7. Koch A. L. 1974; The pertinence of the periodic selection phenomenon to prokaryote evolution. Genetics 77:127–142
    [Google Scholar]
  8. Kubitschek H. E. 1970 Introduction to Research with Continuous Cultures Englewood Cliffs, NJ: Prentice-Hall;
    [Google Scholar]
  9. Miller J. J. 1946; Cultural and taxonomic studies on certain Fusaria. I. Mutations in culture. Canadian Journal of Research 24(C):188–212
    [Google Scholar]
  10. Novick A., Szilard L. 1950; Experiments with the chemostat on spontaneous mutation of bacteria. Proceedings of the National Academy of Sciences of the United States of America 36708–719
    [Google Scholar]
  11. Paquin C., Adams J. 1983a; Frequency of fixation of adaptive mutations is higher in evolving diploid than haploid yeast populations. Nature; London: 302495–500
    [Google Scholar]
  12. Paquin C., Adams J. 1983b; Relative fitness can decrease in evolving asexual populations of Saccharomyces cerevisiae. Nature; London: 306368–371
    [Google Scholar]
  13. Pongratz M., Klingmüller W. 1973; Role of ribosomes in cycloheximide resistance of Neurospora mutants. Molecular and General Genetics 124:359–363
    [Google Scholar]
  14. Trinci A. P. J., Gull K. 1970; Effect of actidione, griseofulvin and triphenyltin acetate on the kinetics of fungal growth. Journal of General Microbiology 60:287–292
    [Google Scholar]
  15. Vogel H. J. 1956; A convenient growth medium for Neurospora (Medium N). Microbial Genetics Bulletin 13:42–44
    [Google Scholar]
  16. Wiebe M. G., Trinci A. P. J. 1991; Dilution rate as a determinant of mycelial morphology in continuous culture. Biotechnology and Bioengineering 38:75–81
    [Google Scholar]
  17. Wiebe M. G., Trinci A. P. J., Cunliffe B., Robson G. D., Oliver S. G. 1991; Appearance of morphological (colonial) mutants in glucose-limited, continuous flow cultures of Fusarium graminearum A3/5. Mycological Research 95:1284–1288
    [Google Scholar]
http://instance.metastore.ingenta.com/content/journal/micro/10.1099/00221287-139-11-2811
Loading
/content/journal/micro/10.1099/00221287-139-11-2811
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