THE CINNAMIC ACID PATHWAY AND HISPIDIN BIOSYNTHESIS IN CULTURES OF POLYPORUS HISPIDUS FRIES by PETER WILLIAM PERRIN B.Sc, University of British Columbia, 1968 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in the Department of Botany We accept this thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA September, 1972 In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying'of this thesis for scholarly purposes may be granted by the Head of my Department or by his representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department of The University of British Columbia Vancouver 8, Canada Date i ABSTRACT The biosynthesis of hispidin, 6-(3,4-dihydroxystyryl)- 4-hydroxy-2-pyrone, was examined in cultures of Polyporus hispidus Fr. Cultural studies were undertaken to determine the most suitable medium for investigating the biosynthesis of this pigment. These studies showed that light was nec• essary for hispidin formation and that the development of basidiocarps with viable spores could be achieved on agar media. On the liquid medium employed for biochemical studies, the maximum rate of hispidin production was observed to lag the maximum rate of growth by about five days. Trimethylhispidin, 4-methylhispidin and yangonin were synthesized for comparative purposes and for dilution in tracer experiments. These and numerous other phenolic and aromatic compounds were employed as references in examinations of nonradioactive culture extracts. P-coumaric, caffeic, £- hydroxybenzoic, protocatechuic and o- and p_-hydroxyphenyl- acetic acids were detected in extracts of the culture medium. Bis-noryangonin (6-(4-hydroxystyryl)-4-hydroxy-2-pyrone) and other possible styrylpyrones were detected in extracts of the mycelium. Tracer experiments established that phenylalanine was metabolized to cinnamic, benzoic, p_-hydroxybenzoic and protocatechuic acids. The incorporation of radioactivit;' 11 into phenyllactic, phenylpyruvic, phenylacetic and rj-hydroxy- phenylacetic acids also was observed. Furthermore, p_-coum- aric acid, caffeic acid and hispidin incorporated radioactiv• ity from phenylalanine. Hispidin also was shown to incor• porate radioactivity from tyrosine, cinnamic acid, p_-coum- aric acid, caffeic acid, malonic acid and sodium acetate. Degradation of the labelled hispidin obtained from these pre• cursors confirms the hypothesis that this molecule is bio- synthesized from a phenylpropanoid moiety with the addition of two equivalents of acetate. Crude and partially purified preparations of several enzymes related to aromatic metabolism were obtained. Phen• ylalanine and tyrosine ammonia-lyase activity were demonstrat• ed in cell-free preparations. Maximum phenylalanine ammonia- lyase activity was obtained from cultures during the logar• ithmic phase of growth. Enzymes capable of hydroxylating cinnamic acid, benzoic acid and bis-noryangonin also were obtained in vitro. iii TABLE OF CONTENTS PAGE ABSTRACT i TABLE OF CONTENTS iii LIST OF TABLES , vi LIST OF FIGURES vii ACKNOWLEDGMENT ix INTRODUCTION 1 LITERATURE REVIEW 4 I. The acetate-polymalonate pathway in fungi 4 II. The shikimic acid pathway in fungi............ 6 III. Aromatic amino acid metabolism in Basidio- mycetes 11 IV. Pigment production in fungi 16 V. Sporophore formation in Basidiomycetes......... 17 CHAPTER ONE. CULTURAL STUDIES OF POLYPORUS HISPIDUS... 21 Introduction 21 Materials and Methods 22 I. Sources of cultures 22 II. Sources of medium constituents 22 III. Media employed 23 IV. Culturing techniques 24 V. Measurements of hispidin production 24 VI. Dry weight determinations 25 Results and Discussion.. 26 I. Comparison of P_. hispidus and P. schwein- itzii 26 II. Growth and pigment production in P. his• pidus 30 III. Sporophore formation in agar cultures of P. hispidus . 45 iv TABLE OF CONTENTS (cont'd) PAGE CHAPTER TWO. CHEMICAL STUDIES OF PHENOLIC ACIDS, STYRYLPYRONES AND RELATED COMPOUNDS 49 Introduction 49 Materials and Methods 49 I. Chemicals 49 II. - Chromatography. 50 III. Spectroscopy 51 IV. Melting points 51 V. Chemical preparations 51 Triacetic lactone. • 51 6-methyl-4-methoxy-2-pyrone. 52 Trimethylhispidin 53 4-methylhispidin 53 Alkaline hydrolysis of trimethylhispidin... 54 3,4-dimethoxycinnamic acid................. 55 3,4-bis-(methoxymethoxy)benzaldehyde 55 • Vera trie acid from trimethylhispidin 56 VI. Radioautography 57 Results and Discussion 58 CHAPTER THREE. RADIOACTIVE FEEDING EXPERIMENTS WITH CULTURES OF POLYPORUS HISPIDUS 70 Introduction 70 Materials and Methods 70 I. Analysis of phenolic acids 70 II. Preparation and administration of radioac• tive compounds 70 III. Detection of radioactivity 71 IV. Recovery of free amino acids 72 14 V. Methylation of C-labelled hispidin 72 Results and Discussion 73 V TABLE OF CONTENTS (cont'd) PAGE CHAPTER FOUR. PRELIMINARY STUDIES OF ENZYMES ASSO• CIATED WITH AROMATIC METABOLISM 92 Introduction 92 Materials and Methods 93 I. Phenylalanine ammonia-lyase........... 93 II. Tyrosine ammonia-lyase.... 94 III. Benzoic and cinnamic acid-4-hydroxylase... 94 IV. Bis-noryangonin-3-hydroxylase 95 Results and Discussion 96 GENERAL SUMMARY AND CONCLUSIONS 100 BIBLIOGRAPHY 104 APPENDICES 113 A. Characteristic of Wrattan filters 113 B. Spray Reagents 114 vi LIST OF TABLES TABLE PAGE I. Mycelial dry weight and pH of medium of cultures of P. hispidus after sixteen days when grown on DM#1 at various initial pH* s 34 II. Colours of phenolic acids in long wave ultra• violet light and in visible light after spray• ing with diazotized-p_-nitroaniline reagent „ 60 III. Characteristics of some styrylpyrones and rela• ted phenolic compounds chromatographed on cellu• lose TLC plates in solvent system C and sprayed with various reagents (Appendix B) 66 IV. Metabolic products from various aromatic com• pounds administered to P. hispidus 82 V. Incorporation of various precursors into hispid• in by 17-day-old cultures of P. hispidus 87 vii LIST OF FIGURES FIGURE PAGE 1* Naturally-occurring styrylpyrones 2 2. Acetate-polymalonate-derived fungal products.... 5 3. Complex polyketides from Basidiomycetes 7 4* Shikimic acid pathway to aromatic amino acids... 8 5. Shikimic-acid-derived metabolites of Basidio• mycetes 10 6. Fungal metabolites of mixed biogenesis 12 7. Transformations of cinnamyl compounds in L. lep- ideus o 14 8. Comparison of the growth of P. hispidus and P. schweinitzii on liquid MYP 27 9. Optical density measurements of ether extracts of the mycelium of P. schweinitzii 28 10. pH change during growth of P_. hispidus on DM#1.. 32 11. Variation in colony diameter with temperature of P. hispidus cultures on MYP agar 35 12. Effect of wavelength of light source on growth and pigment development in agar cultures 37 13. Effect of malt extract and Soytone concentration on colony diameter after fifteen days.. 40 14. Growth and hispidin production of P_. hispidus on GYSS 44 15. Pigment development in the mycelium of P. his• pidus after ten and fifteen days incubation on GYSS 46 16. Sporocarp of P. hispidus ten days after initia• tion on MYP agar 46 17. Diagrammatic representation of two-dimensional chromatogram of authentic samples of phenolic and cinnamic acid derivatives 59 viii LIST OF FIGURES (cont'd) FIGURE PAGE 18. Standard absorbance curve of p_-coumaric acid..... 61 19. Standard absorbance curve of caffeic acid 62 20. Standard absorbance curve of trimethylhispidin... 63 21. Standard absorbance curve of veratric acid 64 22. Ultraviolet spectra of yellow, fluorescent bands from chromatograms of P_. hispidus extracts 68 23. Diagrammatic representation of the compounds de• tected in chromatographed extracts of the medium using 48 hr induction by replacement medium 75 24. Probable pathways of L-phenylalanine degradation in P. hispidus 76 25 Probable relationships of radioactive cinnamic acid derivatives detected in cultures of P_. his• pidus 78 26. Aromatic amino acid metabolism via the cinnamate pathway in P. hispidus 85 27. Biosynthesis and degradation of radioactive his• pidin. 91 28. Phenylalanine ammonia-lyase activity in cultures of P. hispidus 97 29. Alternate routes proposed for the biosynthesis of hispidin in P. hispidus 102 ix ACKNOWLEDGMENT I wish to express my sincere gratitude to Dr. R.J. Bandoni and Dr. G.H.N. Towers with whose facilities and under whose guidance this work was carried out. Their en• couragement, advice and criticism of this manuscript are gratefully acknowledged. The assistance and advice of Dr. C.K. Wat and the facilities provided by Dr. T. Money were greatly appreciated. To my collegues, for helpful discus• sions, and to the members of my committee, for their com• ments on this manuscript, I give my thanks. The financial support of the National Research Council of Canada and of the H.R. MacMillan family is acknowledged. Also, I would like to thank my wife, Janne, for her encouragement throughout this work. INTRODUCTION 1 Naturally occurring sporophores of Polyporus hispidus Fr., P_. schweinitzii Fr. and several species of Gymnopilus contain the styrylpyrone pigment hispidin (Fig. l.)(Bu'Lock and Smith 1961, Edwards et al 1961, Ueno et al 1964, Hat• field and Brady 1971). Gymnopilus also contains the styryl• pyrone bis-noryangonin