Investigating metabolism and interspecies interactions in fungi with the use of chemical modifiers and media variation

Schuler, Philip (2024) Investigating metabolism and interspecies interactions in fungi with the use of chemical modifiers and media variation. Doctoral thesis, University of East Anglia.

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Abstract

Fungi are incredibly diverse and talented producers of secondary metabolites, representing a reservoir of potential natural products of medicinal, industrial and agricultural value. As well as this, edible fungi such as the truffle forming species are also highly prized and of high economic importance. In this work, a variety of fungal cultures were isolated from wild specimens collected within the UK. The potential of these fungi as sources of novel natural products was investigated utilising an OSMAC approach; fungi were cultivated in a range of liquid, semi-solid and solid media, and the metabolite profiles produced were analysed by HPLC and LCMS. As well as screening the fungi in various media, the effect of a range of small molecule elicitors on the metabolite profiles of the fungi was examined. These substances included epigenetic modifiers, biological precursors and enzyme inhibitors. Treatment with these substances altered the metabolite profiles of the fungi in many cases, resulting in increased amounts of particular metabolites compared to controls, or the production of compounds not detected in control fermentations, including biotransformation products. Attempts were made to isolate and identify metabolites produced by the fungi using a variety of extraction, chromatographic, and spectroscopic techniques. Culture extracts from the laboratory fermentations were tested for antibacterial properties, alongside a series of extractions and chromatographic fractions obtained from several species of wild mushrooms. Many of the samples tested showed antibacterial efficacy against a variety of both Gram-positive and Gram-negative species. Several of the extracts obtained from the wild mushroom species proved to be especially promising, in some cases having stronger antibacterial effects on difficult to treat bacteria than Ampicillin.

Hypocrealean fungi are known to be metabolically talented and rich sources of natural products with bioactive potential. European entomopathogenic and arachnogenous (spider-pathogenic) fungi have been poorly investigated, with all of the chemical work to date conducted on Asian strains. Much of this work was conducted on a spider-pathogenic species. Multigene phylogenetic analysis revealed that the culture fits within the Gibellula pulchra clade.

As well as these laboratory experiments, the effect of bacterial co-cultures, epigenetic modifiers, nutritional additives and other small molecule elicitors on mycorrhization of Quercus robur by Tuber aestivum was studied in a nursery pot-trial. It was found that co-culture with particular bacteria lead to an increase in mycorrhization, which may lead to industrial applications.

Item Type:	Thesis (Doctoral)
Faculty \ School:	Faculty of Science > School of Pharmacy (former - to 2024)
Depositing User:	Chris White
Date Deposited:	19 Mar 2025 09:14
Last Modified:	19 Mar 2025 09:14
URI:	https://ueaeprints.uea.ac.uk/id/eprint/98787
DOI:

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