1887

Abstract

Summary: The insect pathogenic fungus produces several extracellular cuticle-degrading proteases and evidence is consistent that one of these, a chymoelastase PR1, is a determinant of pathogenicity. We have shown previously that the wide-domain regulatory circuits of carbon and nitrogen derepression regulate PR1 production. In the present work we have established in addition that PR1 is specifically induced by insect cuticle, but not by other soluble or insoluble proteinaceous substrates. The feeding of elastin or collagen to derepressed established mycelium (starved for carbon and nitrogen) did not enhance PR1 production significantly and the soluble proteins BSA and gelatin rapidly and completely repressed PR1. The carbohydrate polymers cellulose and xylan gave derepressed basal levels of PR1. However, addition of locust cuticle enhanced PR1 production to a level approximately 10-fold that of derepressed mycelium. In order to establish if the enhancing effect of insect cuticle on PR1 production was due to specific induction or merely a reflection of enhanced growth on this insoluble dual carbon and nitrogen source, ergosterol was used as a measure of fungal growth. Expressing enzyme activity per mg dry weight showed that PR1 production in cuticle cultures increased approximately five- and ninefold after 12 and 24 h growth compared with elastin-grown cultures. Thus, the substantial increase in PR1 production on cuticle was shown not to be a function of fungal growth and this confirms that PR1 is induced by a component of insect cuticle; we believe this is the first report of induction by a specific substrate for any microbial protease.

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1994-01-01
2024-04-19
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References

  1. Andersen S.O. 1980; Cuticular sclerotization in Cuticle Techniques. In Arthropods pp 185–217 Edited by Miller T. A. New York: Springer;
    [Google Scholar]
  2. Banerjee A., Ganesan K., Datta A. 1991; Induction of secretory acid proteinase in Candida alhicans. J Gen Microbiol 137:2455–2461
    [Google Scholar]
  3. Charnley A.K. 1984; Physiological aspects of destructive patho¬genesis in insects by fungi: a speculative review. In Invertebrate Microbial Interactions (British Mycological Society Symposium 6) pp 229–270 Edited by Anderson J.M., Rayner A. D. M., Walton D. W.H. London: Cambridge University Press;
    [Google Scholar]
  4. Charnley A.K., St Leger R.J. 1991; The role of cuticle-degrading enzymes in fungal pathogenesis in insects. In The Fungal Spore in Disease Initiation in Plants and Animals pp 267–287 Edited by Cole G. T., Hoch H. C. New York & London:: Plenum Press;
    [Google Scholar]
  5. Cohen B.L. 1980; Transport and utilisation of proteins by fungi. In Microorganisms and Nitrogen Sources pp 412–430 Edited by Payne J. W. San Francisco & London: John Wiley;
    [Google Scholar]
  6. Cohen B.L. 1981; Regulation of protease production in As¬pergillus . Trans Br Mycol Soc 76:447–450
    [Google Scholar]
  7. Cohen B. L., Morris J.E., Drucker H. 1975; Regulation of two extacellular proteases of Neurospora crassa by carbon-, nitrogen- and sulphur-metabolite repression. Arch Biochem Biophys 169:324–330
    [Google Scholar]
  8. Cooper R.M., Wood R.K. S. 1975; Regulation of synthesis of cell wall-degrading enzymes by Verticillium albo-atrum and Fusarium oxysporum f. sp. lycopersici. Physiol Plant Pathol 5:135–156
    [Google Scholar]
  9. Crandall M., Edwards J.E. 1987; Segregation of proteinase- negative mutants from heterozygous Candida albicans . J Gen Microbiol 133:2817–2824
    [Google Scholar]
  10. Drucker H. 1975; Regulation of exocellular proteases in Neuro¬spora crassa: metabolic requirements of the process. J Bacteriol 122:1178–1125
    [Google Scholar]
  11. Hojrup P., Andersen S.A., Roepstrorff P. 1986; Primary structure of a structural protein from the cuticle of the migratory locust, Tocusta migratoria . Biochem J 236:713–720
    [Google Scholar]
  12. Lasure L.L. 1980; Regulation of extracellular acid protease in Mucor miehei . Mycologia 72:483–492
    [Google Scholar]
  13. Matcham S. E., Jordan B.R., Wood D.A. 1984; Methods for assessment of fungal growth on solid substrates. In Microbiological Methods for Environmental Biotechnology (Society for Applied Bac¬teriology Technical Series 19) pp 5–18 Edited by Grainger J. M., Lynch J. M. London&New York: Academic Press;
    [Google Scholar]
  14. Newell S. Y., Miller J.D., Fallon R.D. 1987; Ergosterol content of salt-marsh fungi: effect of growth conditions and mycelial age. Mycologia 79:688–695
    [Google Scholar]
  15. Paterson I. C., Charnley A. K., Cooper R.M., Clarkson J.M. 1993; Regulation of production of a trypsin-like protease by the insect pathogenic fungus Metarhipum anisopliae . FEMS Microbiol Lett 109:323–328
    [Google Scholar]
  16. Seitz L. M., Sauer D. B., Burroughs R., Mohr H.E., Hubbard J.D. 1979; Ergosterol as a measure of fungal growth. Phyto-pathology 69:1202–1203
    [Google Scholar]
  17. Sessoms D.B., and Lilly W. W. 1986; Derepressible proteolytic activity in homokaryotic hyphae of Sch Dophyllum commune . Exp Mycol 10:294–300
    [Google Scholar]
  18. Shapiro B.E., Gealt M.E. 1982; Ergosterol and lanosterol from Aspergillus nidulans . J Gen Microbiol 128:1053–1056
    [Google Scholar]
  19. St Leger R.J., Charnley A.K., Cooper R.M. 1987a; Characterisation of cuticle degrading proteases produced by the entomopathogen Metarhipum anisopliae . Arch Biochem Biophys 253:221–232
    [Google Scholar]
  20. St Leger R.J., Cooper R.M., Charnley A.K. 1987b; Distribution of chymoelastases and trypsin-like enzymes in five species of entomopathogenic deuteromycetes. Arch Biochem Biophys 258:123–131
    [Google Scholar]
  21. St Leger R.J., Cooper R.M., Charnley A.K. 1987c; Production of cuticle degrading enzymes by the entomopathogen Metarhipum anisopliae during infection of cuticles from Calliphora vomitoria and Manduca sexta. J Gen Microbiol 133:1371–1382
    [Google Scholar]
  22. St Leger R.J., Durrands P. K., Charnley A.K., Cooper R.M. 1988a; Role of extracellular chymoelastase in the virulence of Metarhhium anisopliae for Manduca sexta . J Invertebr Pathol 52:285–293
    [Google Scholar]
  23. St Leger R.J., Durrands P. K., Cooper R.M., Charnley A.K. 1988b; Regulation of production of proteolytic enzymes by the entomopathogenic fungus Metarhipum anisopliae . Arch Microbiol 150:413–416
    [Google Scholar]
  24. St Leger R., Staples R.C., Roberts D.W. 1991; Changes in translatable mRNA species associated with nutrient deprivation and protease synthesis in Metarhipum anisopliae . J Gen Microbiol 137:807–815
    [Google Scholar]
  25. Tuksida K. 1980; Analyis of vitamin D2 isomers. Methods Enpymol 67:326–335
    [Google Scholar]
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