In spite of significant shortcomings among existing clinical antifungal agents, the rate of development of new therapeutics has been sluggish, and the mortality rate caused by fungal diseases has remained almost unchanged. Natural products have provided useful templates for the development of several of the most important therapeutic antifungal agents. In particular, fungi have been rich sources of antifungal natural products, and many fungal species remain chemically underexplored. Our research program has focused on fungicolous and coprophilous fungal niche groups. These types of fungi often show antagonistic effects toward host or competitor fungi—a phenomenon hypothesized to be associated in part with the production of antifungal metabolites. Earlier results reported from our research program have shown that studies of such fungi can be effective approaches to the discovery of new bioactive natural products, including antifungal agents. During our continued efforts to discover new antifungal and antiinsectan natural products, diverse fungal metabolites were obtained from complex fermentation extracts by use of various chromatographic methods. In addition to previously known compounds and simple analogues thereof, structurally interesting new metabolites were encountered. Those isolated from fungicolous fungi include ten new caryophyllene-type sesquiterpenoids from a Pestalotiopsis sp., three of which contain previously undescribed ring systems or new skeletons. The remainder are oxidized analogues of punctaporonins. Seven new polyketide-derived metabolites were obtained from another Pestalotiopsis isolate, in this case, P. disseminata, and two unusual ring systems were identified. A distinctive biosynthetic pathway was proposed for these seven polyketides. Members of another class of polyketides (pyrenocines), which contain pyrone or thiopyran units, were encountered from Penicillium paxilli. One of the three new pyrenocine analogues obtained contains an adenine unit—a rare feature among fungal secondary metabolites. Chemical investigation of another Penicillium sp., P. lanosum, afforded a new fumiquinazoline analogue, as well as a compound previously described in a thesis of a member of our research group. In work described here, the original stereochemical assignment was revised, and the compound was renamed as lanosindole. Metabolites isolated from this fungicolous Penicillium isolate have amino acid origins in common, and two of them showed antiinsectan activity. Seven new polyketide alcohols were obtained from the coprophilous fungus Podospora appendiculata. Two of them contain a tetrahydropyran unit and three are acyclic, differentiating them from other known members of this class. Finally, funiculosin B, an antifungal metabolite of mixed biogenetic origin containing a rare tetrahydroxycyclopentanyl moiety, was isolated from a flower-colonizing isolate of Capnodium sp. The structures of the compounds described above were determined mainly by analysis of NMR and MS data. Synthetic modification, X-ray crystallographic analysis, and ECD data analysis in conjunction with molecular modeling were applied to their stereochemical assignments. The results described in this thesis indicate that fungicolous and coprophilous fungi are prolific producers of new natural products, some of which display activity in assays of medical and agricultural relevance. Although most of the new compounds described here were inactive against pathogenic fungi, the rich diversity of chemistry encountered suggests potential for this ecology-based approach in the discovery of new bioactive natural products.

The mechanisms of dung inhabiting insects' heterotrophic succession were studied by preventing the colonisation of early successional insect. The early successional insect, predominantly the large larvae of Calyptratae Diptera, both facilitated and inhibited the later establishing insect. Whereas the removal of early successional species affected negatively the late successional Coleoptera (facilitation), the small late successional larvae of Acalyptratae Diptera were affected positively (inhibition). The patterns retrieved from the heterotrophic succession strongly resemble the patterns retrieved from the autotrophic, mostly plant, succession Therefore it is possible to suggest, that similar mechanisms are behind both the autotrophic and the heterotrophic succession.

Specimens of animal dung were collected from various areas of the state of Utah. These were cultured by placing a few small pieces in a culture dish over moistened sphagnum moss and filter paper. The cultures were observed periodically and specimens were studied as they matured upon the substratum. A total of eighty-four species representing three orders and fifteen genera are reported. Of these, nine species have not previously been described. Included is one species, Tripterospora erostrata, from the order Plectascales of the Series Plectomyceteae. Cited from the order Sphaeriales of the Series Pyrenomyceteae are forty-nine species as follow: Coniochaeta, two species; Delitschia, nine species; Hypocopra, two species; Pleophragmia, two unnamed species; Sordaria, thirteen species; and Zygospermella, one species. From the order Pezizles of the Series Discomyceteae are reported thirty-four species as follows: Ascobolus, five species, including one unnamed species; Ascophanus, thirteen species; Cheilymenia, four species; Peziza, three species; Lasiobols, two species, one unnamed species; and Saccobolus, five species, two of which are reported for the first time.

Thesis (doctoral)--Swedish University of Agricultural Sciences, 2003. / Appendix consists of reproductions of six papers and manuscripts, five co-authored with others. Thesis documentation sheet inserted. Includes bibliographical references. Issued also electronically via World Wide Web in PDF format; online version lacks appendix of papers.

Les microfossiles non-polliniques, des restes de divers organismes préservés dans les sédiments lacustres ou tourbeux, sont de plus en plus couramment employés en paléoécologie. Parmi ces microrestes, les spores de champignons coprophiles sont privilégiées dans les reconstructions des activités humaines telles que les activités pastorales. L’aptitude de ces spores à refléter la présence ou l’abondance des troupeaux n’est pas encore complètement comprise. Des analogues modernes ont été collectés dans deux zones d’estive, dans les montagnes du Pays Basque et d’Ossau. Des analyses de gradients contraintes par des variables environnementales ont permis d’identifier des assemblages non-polliniques associés à diverses conditions environnementales en contexte humide et terrestre. Un cortège d’ascospores de groupes coprophiles liées aux activités pastorales a pu être isolé. Les référentiels ont également fourni des informations sur la portée spatiale de l’information non-pollinique.Les microfossiles non-polliniques ont été étudiés dans quatre séquences tourbeuses en complément d’autres sources d’informations paléoenvironnementales (pollen, signal incendie). Ils ont fourni les informations sur les dynamiques des quatre sites durant l’Holocène et les périodes historiques. Les résultats des référentiels sont appliqués à l’interprétation des dynamiques pastorales. Les résultats modernes et fossiles montrent que la charge pastorale n’est pas le seul paramètre qui influence les signaux coprophiles ; ces spores pourraient avoir un potentiel d’indicateurs paléoenvironnementaux et pastoraux plus étendu qu’attendu.Les ascospores de groupes coprophiles sont décrites et illustrées ainsi que d’autres microfossiles fongiques, algaux et indéterminés. / Non-pollen palynomorphs, microscopic remains produced by a variety of organisms and preserved in peat and lake sediments, are now more widely used in palaeoenvironmental studies. In particular, spores of coprophilous fungi are considered as an adapted tool to reconstruct past land-use such as pastoral activities. However, their ability to reflect the presence and/or the number of cattle is not fully understood yet. Modern analogs from summer pastures in the Basque Mountains and the Ossau valley have been collected. Numerical analysis of modern non pollen-palynomorphs and environmental variables helped to distinguish several pools of microremains associated to distinct environmental conditions in both terrestrial and wet ecosystems. A group of ascospores of dung-related fungi clearly related to grazing activities was isolated. The modern dataset also provided useful information on the spatial scale represented by non-pollen palynomorphs. Fossil non-pollen palynomorphs from four peat records, combined with other palaeoenvironmental data (pollen, fire frequencies), have been studied. They informed on the evolution of the local conditions of the wetlands during Holocene and historical times. The modern data set is used to aid interpretation of the dynamics of past land-use and pastoral activities. The results from both modern and fossil approaches show that other parameters than the grazing pressure can induce variability in the copropilous signals; the indicative value of dung-related ascospores might be broader than expected. The ascospores of dung-related taxa are described and illustrated, alongside with other fungal, algal and unidentified microremains.