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1	Reaktionsmuster und morphogenetisches Potential isolierter Mycobionten (Flechtenpilze) und die Bedeutung für den Symbioseorganismus Flechte Etges, Sabine. January 2001 (has links) (PDF) Düsseldorf, Universiẗat, Diss., 2001. Mycobiont
2	Synthese von Alternaria-Metaboliten und Graphislactonen Altemöller, Martina January 2008 (has links) Zugl.: Karlsruhe, Univ., Diss., 2008
3	Evolution and Expression of polyketide synthase gene in the lichen-forming fungal families Cladoniaceae and Ramalinaceae Timsina, Brinda Adhikari January 2012 (has links) Fungal polyketides are synthesized by polyketide synthases (PKS) encoded by PKS genes. The function of many PKS genes is unknown and the number of PKS genes exceeds the number of polyketides in many genomes. The lichen-forming fungi, Cladonia and Ramalina have chemical variants separated by habitat suggesting that environmental conditions may influence polyketide production. The goal of this thesis was to examine evolutionary relationships as a framework to investigate PKS gene function in the lichen-forming fungal families Cladoniaceae and Ramalinaceae. A phylogenetic analysis of the genus Ramalina (Chapter 2) using nuclear and mitochondrial ribosomal DNA sequences showed monophyly for seven species and included three species, which were not examined in phylogenies prior to this study. One monophyletic species, R. dilacerata was chosen for further tests of the effect of growing conditions on PKS gene expression (Chapter 3). Growth media containing yeast extracts produced the largest colony diameters and the fewest number of polyketides. A significant negative relationship occurred between colony diameter and number of secondary metabolites. Expression of two types of PKS genes was correlated with pH-level and media conditions that produced larger numbers of secondary products in R. dilacerata. A PKS gene phylogeny was constructed for 12 paralogs detected in members of the C. chlorophaea complex (Chapter 4) and gene selection was inferred using dN/dS estimations. The gene phylogeny provided evidence for independent origins and purifying and positive selection of PKS paralogs. This research provided insight into the evolution of PKS genes in the C. chlorophaea complex and identified potential genes that produce non-reduced polyketides present in C. chlorophaea. This thesis provided evidence for diversification of both morphological and chemical species and monophyly of previously unstudied Ramalina species. This research also supported theories of secondary metabolite synthesis based on growing conditions of R. dilacerata, and it revealed that PKS genes under selection in the Cladonia chlorophaea group provide the lichen with the adaptive capacity to survive under variable conditions. Knowledge of the ecological function of fungal polyketides can be valuable for conservation management and policy makers; and for understanding the potential pharmaceutical roles of these natural products. Evolution Gene expression Polyketide synthase paralogs Lichen-fungi Culture mycobiont Cladonia Ramalina
4	The puzzle of lichen symbiosis : Pieces from Thamnolia Onuț-Brännström, Ioana January 2017 (has links) Symbiosis brought important evolutionary novelties to life on Earth. Lichens, the symbiotic entities formed by fungi, photosynthetic organisms and bacteria, represent an example of a successful adaptation in surviving hostile environments. Yet many aspects of the lichen symbiosis remain unexplored. This thesis aims at bringing insights into lichen biology and the importance of symbiosis in adaptation. I am using as model system a successful colonizer of tundra and alpine environments, the worm lichens Thamnolia, which seem to only reproduce vegetatively through symbiotic propagules. When the genetic architecture of the mating locus of the symbiotic fungal partner was analyzed with genomic and transcriptomic data, a sexual self-incompatible life style was revealed. However, a screen of the mating types ratios across natural populations detected only one of the mating types, suggesting that Thamnolia has no potential for sexual reproduction because of lack of mating partners. Genetic data based on molecular markers revealed the existence of three morphologically cryptic Thamnolia lineages. One lineage had a clear recombination structure and was found in the tundra region of Siberia, shorelines of Scandinavia, and Aleutian Islands. The other lineage was allopatric with the previous, and was highly clonal; only two haplotypes were found across the alpine region of central and southeastern Europe. However, the third lineage was sympatric with the other two, had a worldwide distribution, and although highly clonal, showed a recombinant population structure. Our data could not reveal whether the signs of recombination resulted from rare recombination events due to the extreme low frequency of the other mating type or ancestral variation before the loss of sexual reproduction. However, investigation of Thamnolia’s green algal population showed that in different localities, different algal genotypes were associated with the same fungal genotype. Furthermore, data suggest that Thamnolia carried several algal genotypes within its thalli and shared them with other distantly related but ecologically similar fungal species. Thamnolia lichen symbiosis photobiont mycobiont phylogeography MAT-loci barcoding NGS genome transcriptome Ice Age Natural Sciences Naturvetenskap
5	Erdflechten und ihre Gesellschaften in Nordhessen mit besonderer Berücksichtigung der morphologischen und genetischen Variabilität bei Cladonia furcata (Hudson) Schrader / Terricolous lichens and their communities in North Hessen (Germany) with special emphasis on the morphological and genetical variability of Cladonia furcata (Hudson) Schrader Günzl, Bettina 22 January 2004 (has links) No description available. Mathematics and Computer Science 580 Pflanzen (Botanik) Nordhessen Flechten Erdflechtengesellschaften Rote Liste-Arten Schutzmaßnahmen Cladonia furcata Flechten-Inhaltsstoffe morphologische Variabilität genetische Variabilität ITS rDNA ITS-Varianten Photobiont Asterochloris Mycobiont North Hessen (Germany) lichens terricolous lichen communities Red Data Species protective measures Cladonia furcata chemical variation morphological variability genetical variability ITS rDNA ITS-variants photobiont Asterochloris mycobiont 42.44 42.51 42.48 WWH 000: Flechten, Lichenes {Botanik}

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