<p>Lichen-forming fungi employ a successful mode of nutrition as symbiotic partners with green algae and/or cyanobacteria (the photobiont). Nearly one fifth of all known fungi are obligate lichen formers, yet we know little of how they find compatible partners and establish long-lived symbiotic relationships. The combined growth of these symbionts forms a body (thallus) with emergent properties unlike either of the symbionts individually grown. Based on other well-studied eukaryotic systems, the development of a lichen thallus must rely upon the successful identification and collaboration of these two very different organisms. Identifying the molecular basis of microbe recognition and interactions remains one of the greatest challenges in studying symbiotic systems. </p><p>In this thesis, I determine the stage in which to begin looking for lichen symbiosis specific genes, and then examine mycobiont and photobiont genes that, when compared to the aposymbiotic state, are upregulated in the symbiotic state. Using the symbiosis between the mycobiont <italic>Cladonia grayi</italic> and the photobiont <italic>Asterochloris</italic> sp., as well as scanning electron microscopy observations of the earliest stages of contact between <italic>C. grayi</italic> and <italic>Asterochloris</italic> sp., I determined that the mycobiont undergoes a specific change in phenotypic growth in response to <italic>Asterochloris</italic> sp. This change is particular to the lichen symbiosis, and is not observed with algal shaped inanimate objects or algae other than <italic>Asterochloris</italic>. I then used this phenotypically defined stage that is exclusive to lichen symbiosis to begin studying the the genetic and molecular mechanisms underlying the development of a stratified lichen thallus. Using suppression subtractive hybridization to determine differential gene expression, fungal and algal libraries were made of upregulated genes in the first 2 stages of lichen symbiosis. The symbiotic expression levels of select genes were then verified using quantitative PCR. Lastly, a candidate gene for involvement in lichen symbiosis was transformed into <italic>Saccharomyces cerevisiae</italic> to test for protein function.</p><p>Further results of this study show that the fungal protein products of genes upregulated in lichen symbiosis show significant matches to proteins putatively involved in fungal self and non-self recognition, lipid metabolism, negative regulation of glucose repressible genes, an oxidoreductase, a dioxygenase, and a conserved hypothetical protein. Algal genes that are upregulated in lichen symbiosis include a chitinase-like protein, an amino acid metabolism protein, a dynein related protein, and a protein arginine methyltransferase. Furthermore, genes that are expressed in the early stages of lichen symbiosis are common varying metabolic pathways. Furthermore stages 1 and 2 of development are marked not by a drastic change in transcriptional products, but instead by an overall change in genes that are already expressed. Finally, the <italic>Cladonia~grayi Lip3</italic>was cloned in its entirety from genomic DNA and cDNA, was predicted to be secreted using signal peptide prediction software, and shown to be a functioning secreted extracellular lipase in yeast.</p><p>I conclude that many genes are involved in the interactions of symbionts and the development of a stratified lichen thallus, and that many more genes remain to be discovered. Furthermore, the possibility that genes exist in either symbiont that are specific to lichen symbiosis remains, and that their discovery awaits the creation of better genomic tools for \textit{Cladonia~grayi} and <italic>Asterochloris</italic>.</p> / Dissertation

Effects of stand type on ground lichen height and species richness in boreal forests.   P. contorta as an alternative to P. sylvestris in terms of providing a suitable habitat   Maria Johansson     Abstract     Lichen-rich forests are essential to reindeer but up to 50 % of the lichen-rich areas in Sweden have been lost since the 1950s. Ground lichens thrive in pine-heaths and with an increasing area of plantations of the non-native tree species Pinus contorta, as an alternative to the native P. sylvestris, it is important to investigate if P. contorta can provide such an optimal habitat to ground lichens. The purpose of this study was to assess if forest characteristics, such as tree density, canopy cover and production capacity, affect the abundance and growth of five lichen species (Cladonia rangiferina, C. arbuscula/mitis, C. stygia, C. stellaris and Cetraria islandica) and whether these characteristics differ between forests dominated by P. contorta and forests dominated by P. sylvestris. Fieldwork was conducted in Norrbotten and Västerbotten on sample plots previously used by the Swedish National Forest Inventory (SNFI). The statistical analysis was based on data collected from 22 sample plots, 11 of each forest type, visited during July and September 2015. No statistical significant differences were found between forest characteristics of the two forest types, and none of the forest characteristics were found to relate to lichen height. Forest age did not seem to have an effect on ground lichens, while both canopy cover and production capacity were found to negatively relate to the proxy for lichen biomass as well as the abundance of the most common lichen species, C. rangiferina and C. arbuscula/mitis. The result suggests that a shadier canopy as well as a higher production capacity contributes to a reduced distribution of ground lichens.   Keywords: Ground lichens, Pinus contorta, Pinus sylvestris, forest characteristics, forestry, reindeer husbandry

The aim with this study was to develop a method to estimate total area of hair lichens and to compare morphological traits and water storage in them. Hair lichens are an important component of the epiphytic flora in boreal forests. Their growth is primarily regulated by available water, and light when hydrated. Lichens have no active mechanism to regulate their water content and their water holding capacity (WHC, mg H2O/cm2) is thus an important factor for how long they remain wet and metabolically active. In this study, the water uptake and loss in five hair lichens (Alectoria sarmentosa, three Bryoria spp. and Usnea dasypoga) were compared. Their area were estimated by combining photography, scanning and a computer programme that estimates the area of objects. Total area overlap of individual branches was calculated for each species, to estimate total area of the lichen. WHC and specific thallus mass (STM) (mg DM/cm2) of the lichens were calculated. Bryoria spp. had a significantly lower STM compared to U. dasypoga and A. sarmentosa, due to its thinner branches and higher branch density. Bryoria also had a lower WHC compared to A. sarmentosa, promoting a rapid uptake and loss of water. All species had a significant relationship between STM and WHC, above a 1:1 line for all species except U. dasypoga. The lower relationship in U. dasypoga is explained by its less developed branching in combination with its thick branches.

No description available.

More than 300 species of lichens are used by people across the world. mostly as dyes or medicines. Some lichens are used as food, although previous studies indicate that lichens are indigestible to humans. Bryoria fremontii is an example of a lichen that is an important traditional food throughout its range. A literature review and interviews with a knowledgeable Seewepemc elder reveal that this lichen is traditionally harvested. washed, and cooked in specific ways that are deeply rooted in its ecology and chemistry. A population study indicates that the traditional practice of avoiding areas with light-coloured and greenish lichen selects for locations with Bryoria fremontii and avoids similar-looking toxic species. A cooking experiment suggests that cooking does not make lichen carbohydrates digestible, but when the lichen is cooked with other foods it can capture digestible carbohydrates from them that would otherwise be lost, thus increasing available carbohydrates by 23-122%.

The effects of lichen ground cover (predominantly Cladina stellaris) on the growth of Picea mariana at Schefferville, Quebec and Pinus sylvestris at Kevo, Finland, was investigated in situ. Effect on seedling establishment was inferred through examining status quo conditions. While contiguous mat cover precluded establishment, its margins provided ameliorated conditions suitable for establishment. Moss covered areas were the most preferred sites. At Schefferville, ten perturbations involving fertilization, lichen removal, polyethylene overlays, and aqueous lichen extract application were effected on sixteen experimental plots. Branch elongation, needle nitrogen and bole diameter were statistically analyzed as functions of various monitored edaphic conditions. Leader elongation and needle nitrogen was measured at Kevo. Lichen presence over the term of both studies showed net beneficial effect on the trees; lichen extracts had significant detrimental effects. Seed germination was suppressed by lichen presence but enhanced by lichen induced low soil pH when in contact with the soil.

No description available.

This thesis describes the isolation and structure elucidation of ten novel secondary metabolites from one fungus (Pycnoporus cinnabarinus), four lichens (Chrysothrix xanthina, Candelaria concolor, Ramalina glaucescens and Xanthoria parietina), three algae (Plocamium mertensii, Laurencia filiformis and Laurencia elata), two plants (Haemodorum simplex and Dianella callicarpa) and one sponge (Dactylospongia sp). The structures of these isolated compounds were elucidated by a combination of spectroscopic and chemical methods. This thesis also reports two new crystal structures, the identification of two new methylsilylated derivatives as well as the isolation of thirty seven previously reported compounds in which the complete structural assignment by one and two dimensional nuclear magnetic resonance spectroscopy (NMR) has been carried out on known compounds with incomplete or no NMR spectroscopic data. Furthermore, detailed spectroscopic analyses resulted in the re assignment of 1H and 13C chemical shifts for several previously isolated natural products. The biological screening (antimicrobial, antiviral and antitumor assays) of crude extracts and isolated natural products has also been presented. The application of chemical profiling techniques including GCxGC and high pressure liquid chromatography-nuclear magnetic resonance (HPLC-NMR) were utilised to assist with the natural product dereplication process (chemical profiling), monitor chemical degradations in situ and to identify the presence of new natural products and artefacts. In total, fifteen separate terrestrial and marine organisms were investigated.

Thesis (M.S.)--Oregon State University, 2008. / Printout. Includes bibliographical references. Also available on the World Wide Web.

Made available in DSpace on 2014-06-11T19:32:56Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-07-13Bitstream added on 2014-06-13T20:04:40Z : No. of bitstreams: 1 santos_jmg_dr_botib.pdf: 895282 bytes, checksum: 0c35f9663fd942b07f94d336af95df45 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Este trabalho teve o objetivo de verificar a distribuição de espécies de fungos liquenizados sobre 573 troncos de onze espécies de leguminosas encontradas em área de cerrado, tanto nativas quanto estranhas ao ecossistema e plantadas num arboreto ao lado de uma área de vegetação natural. O levantamento de dados para estudo fitossociológico foi feito com método do elástico e os cálculos realizados em programa especialmente desenvolvido para esse trabalho. Cálculos de similaridade, diversidade, análises de variância e análise multivariada foram realizadas para descrever as comunidades de liquens e relacioná-las com forófitos e ambiente. O estudo da distribuição dos 4561 liquens (144 espécies) em 122 troncos de Copaifera langsdorffii (copaíba) do cerrado, cerradão e arboreto mostrou comunidades diferentes para os habitats, tipos de cascas e lados dos troncos. As espécies de maior valor de importância variam sua estratégia de ocupação com o ambiente. Embora localizado ao lado da vegetação nativa, a comunidade liquênica do arboreto é menos rica e abundante. O estudo da distribuição das 8840 ocorrências, incluindo 5535 liquens (176 espécies) em 157 troncos de cinco espécies de leguminosas do arboreto mostrou comunidades diferentes nos forófitos e maior agregação de espécies e indivíduos a cerca de um metro de altura. Liquens são mais importantes em todas as árvores, exceto no pau-brasil, onde as briófitas dominam. Umidade do ar, luminosidade, pH e diâmetro do tronco explicam as preferências por habitat. A habilidade de dispersão é o fator de sucesso da grande maioria das espécies. Cassia ferruginea (cássia) é o forófito com mais espécies e indivíduos de liquens enquanto Caesalpinia ferrea (pau-ferro) tem os menores números. Usnea spp. e formas crostosas preferem claramente troncos de cássia... / This works deals with the lichen distribution on 573 trunks of eleven Leguminosae species found in a cerrado forest region, both native and strange to the ecosystem and grown in an arboretum nearby. The phytosociological data were obtained by the rubber method and treated by software specially developed for. Similarity, variance and multivariate analysis were used to characterize the communities and related them to phorophyte species and environment. The study of the 4561 lichens (144 species) on 122 trees of Copaifera langsdorffii from cerrado and cerradão vegetation, as well from the arboretum, revealed distinct communities for habitats, bark types and aspect. The species of greater Importance changes its strategy of substrate occupation according the environment. Nevertheless located just beside the natural vegetation, the lichen community of the arboretum has lower values of richness and abundance. The study of the distribution of the 8840 occurrences that included 5535 lichens (176 species) on 157 trunks of five tree Leguminosae in the arboretum showed a greater species and individual aggregation about one meter above the ground. Here, lichens are the most important epiphytes on all tree species except on Caesalpinia ferrea, where bryophytes dominate. Air humidity, luminosity, bark pH and diameter explain the habitat preferences. The skill to efficient dispersion might be the success factor of the great majority of the lichen species. Cassia ferruginea is the phorophyte bearing more lichen species and individuals, while Caesalpinia ferrea exhibit the lower numbers. Usnea spp. as well crustose forms clearly prefer trunks of C. ferruginea, which is indicate here to form ecological corridors across anthropized areas and linking preservation areas. The study of the distribution of the 3157 occurrences of lichenized... (Complete abstract click electronic access below)