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Complexity of lichen symbiosis
Černajová, Ivana ; Škaloud, Pavel (advisor) ; Palice, Zdeněk (referee) ; Spribille, Toby (referee)
Lichens are currently viewed as complex symbiotic systems. In addition to the main mycobiont and photobiont, a variety of associated fungi, bacteria and algae/cyanobacteria (minor/accessory photobionts) have been recognized. Their diversity has been intensively studied, but is still far from being fully apprehended. Likewise, recognition of the significance of the associated organisms to the whole system is still at the beginning but various crucial roles, from constitutive morphogenetic through physiological to various means of increasing the lichen's fitness, have already been suggested. The present thesis attempts to approach lichens in their full complexity. Focusing on two model systems; the Cladonia-Asterochloris association and ecologically delimited communities of Verrucariaceae; it aims: i) to examine patterns in photobiont choice and their relationship to lichen ecology; ii) to set a framework for in-vitro mycobiont-photobiont compatibility testing; iii) to explore the diversity of selected associated fungi and their possible relationships with the lichen host. We have shown that Verrucariaceae in the intertidal zone associate with largely understudied Ulvophycean photobionts. They mainly belong to Kornmanniaceae, Ulvales, and include a variety of novel lineages, one of which was...
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Vliv potravní preference všenek (Phthiraptera: Amblycera) na formování jejich mikrobiomů
ŽIŽKOVÁ, Kateřina
Microbiome diversity of chewing lice belongs to generaly unexplored topics. This thesis provides the first insight into the microbiomes of 15 chewing lice species of the genus Menacanthus. We detected the presence of two dominant symbiotic bacteria, which occurred in almost all species. We also compared the microbiome diversity of lice with different diet preferences (blood feeding and feather feeding species). Based on these analyses, we identified the main determinants shaping the microbiomes of Menacanthus lice. The microbiomes are namely affected by Menacanthus species identity, its geographical origin, dietary niche, and the extent of the host spectrum that the lice parasitize.
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Comparative methods for studying adaptive traits of fungal symbionts
Veselská, Tereza ; Kolařík, Miroslav (advisor) ; Voigt, Kerstin (referee) ; Dvořák, Miloň (referee)
The kingdom Fungi encompasses an estimated 2.2 to 6.2 million species that occupy diverse environments, including aquatic, extremely dry, and hot or frosty habitats all over the world. To cope with adverse environmental conditions, fungi have developed numerous adaptations and life strategies, including symbiosis with other organisms, ranging from close, reciprocally beneficial (mutualistic) associations to severe pathogenic infestations. These interactions have an enormous impact on ecosystem functioning, with implications for agriculture and human health. For this reason, understanding the mechanisms enabling the successful development of fungal interactions is necessary for their efficient management. Recent advances in different 'omics' approaches have enabled us to compare species responses to the environment in a more complex way than before and to gain deeper insights into the adaptive mechanisms underlying specific life strategies. My thesis is divided into four main sections. In the first section, I sum up findings about adaptations of fungal symbionts of plants and animals. Then, I introduce two fungal genera, Geosmithia and Pseudogymnoascus, to which I applied comparative methods for tracking adaptive traits. The ecological diversity of the genus Geosmithia allows to trace adaptive...
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Photobiont dynamics of Stereocaulon lichens
Vančurová, Lucie ; Škaloud, Pavel (advisor) ; Bérešová, Anna (referee) ; Dal Grande, Francesco (referee)
7 Abstract Lichens are an iconic example of symbiosis. They are widespread throughout the world. In some ecosystems, lichens are dominant autotrophs, sometimes one of the few living organisms capable of surviving local conditions. They grow on a variety of substrata, including artificial surfaces. Great diversity of their life strategies is related to the diversity of symbiotic partners forming the lichen thalli, which remains largely unresearched. Lichens as sessile organisms often have to face a changing environment or adapt to conditions at new localities where their propagules can spread. We have chosen the widespread genus Stereocaulon as a model system for studying symbiotic relationships in lichens and the connection of this relationships with environmental conditions. The main goals of this thesis were (1) to uncover the diversity of phycobionts (i.e., green algal photobionts) associated with Stereocaulon within the whole genus and particular species-level lineages; (2) to identify environmental factors affecting the distribution of phycobionts and their relationships with mycobionts on a global and local scale; and (3) to inspect the possibility of sharing phycobiont pool with other lichens and soil. For this purpose, we used phylogenetic analyses (ITS rDNA, 18S rDNA, rbcL, and actin type I gene),...
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The role of trehalose in mycorrhizal associations
Šoch, Jan ; Ponert, Jan (advisor) ; Hála, Michal (referee)
Mycorrhizal symbiosis is a widely spread phenomenon in nature. A translocation of nutrients occurs between symbionts with disaccharide trehalose playing a key role in the process. However, this saccharide fulfils many important roles in metabolism of fungi and plants. Fungi use trehalose mainly as storage and transport saccharide. On the other hand, trehalose occurs in extremely low amounts in plants where it acts as a signal molecule. Thus it is likely that the saccharide could be used by the fungus to manipulate plant metabolism on a physical interface between symbionts. Trehalose has a similar function in many parasitic interactions. In most cases of mycorrhizal associations trehalose synthesis creates a carbon sink in mycelium which leads to saccharide transfer from the host plant to the fungus. Completely different situation occurs in the types of mycorrhizal symbiosis, where saccharides are translocated from a fungus to a plant. Some plants can utilize trehalose effectively as a sole source of energy. Consequently, the question raises - could such plants gain fungal trehalose on purpose as a source of energy and carbon? This review aims to assess and discuss the mentioned possibilities considering available literature. Key words: mycorrhiza, orchids, parazitism, saccharides, sink, symbiosis,...
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Specific features of streptomycetes isolated from human tissues
Kodatová, Anežka ; Petříčková, Kateřina (advisor) ; Zikánová, Blanka (referee)
This bachelor thesis focuses on activities of the bacterial genus Streptomyces in relations to plants, animals and human. Many cases of their symbiotic relationships with plants are known, but there is also a common plant pathogen S. scabies. As a primary soil bacteria, their association with animals is infrequent, but not exceptional. Symbiotic relationships have been observed for example in several insect species. Streptomyces have been repeatedly isolated from the human microbiome, however only a little information about their influence on human body is available. Due to the wide production of secondary metabolites affecting other microorganisms, their role can be assumed as significant. The relationship between human Streptomyces and human could have a parallel in the Streptomyces symbiosis with plants and insects, but it can also have certain effects on pathogenesis. The ability of beta haemolysis was demonstrated in tested strains. In addition, there are cases of serious diseases caused by Streptomyces. Next to the relatively common actinomycosis in the regions of Sudan and India, diseases such as pneumonia or abscess were reported.
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Prokaryotic symbionts of free-living anaerobic protists
Poláková, Kateřina ; Čepička, Ivan (advisor) ; Hampl, Vladimír (referee)
Anaerobní prvoci jsou organismy obývající ředí bez přítomnosti kyslíku. Najdeme je anoxických habitatech jako jsou mořské a sladkovodní sedimenty, komunální skládky, nesmíme opomenout zástupce žijící v bachoru přežvýkavců, trávicím traktu švábů a dalších živočichů. Většinou mají anaerobní deriváty mitochondrií, často hydrogenosomy, organely produkující vodík. Metabolismus anaerobních prvoků je ve srovnání s aerobními organismy méně efektivní Časté interakce anaerobních ický my však mohou Symbiózy mezi anaerobními běžné a vznikly u zástupců mnoha anaerobních linií. žít buď endosymbioticky, uvnitř buňky hostitele, nebo ektosymbioticky, na povrchu hostitelské buňky. Dvě ekologicky významné skupiny prokaryot si dokázaly osvojit život symbiotickém vztahu volně žijícími anaerobními prvoky anogenní archebakterie, osídlující hlavně , využívají vodík nické sloučeniny k anu a síran redukující bakterie, žijící hlavně na povrchu buněk, využívají vodík a různé organické sloučeniny k redukci síranu na sulfan. Velmi málo se ví o bližším charakteru těchto vztahů druhové identitě a hostitelské specifitě prokaryotických symbiontů. Další výzkum je nutný pro pochopení fenoménu symbióz v anoxickém světě. Klíčová slova: anaerobní prvoci symbióza anogenní archebakterie síran redukující bakterie
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Ecological aspects affecting microbiota in the digestive tracts of birds
Schmiedová, Lucie ; Kreisinger, Jakub (advisor) ; Mrázek, Jakub (referee) ; Gvoždíková Javůrková, Veronika (referee)
The results indicate that songbird GM is dominated by the bacterial phyla Proteobacteria, Firmicutes, Actinobacteria, Tenericutes, Bacteroidetes and Chlamydia, a community that differs from that of mammals. A t the interspecies l evel, GM composition is mainly influenced by phylogeny and less so by sampling site. While ecological factors , and especially diet , are important GM predictors in mammals, the effect of ecological factors , including diet , have a much smaller effect on inte r - and intraspecific variability in songbird GM composition . Our data from barn swallows ( Hirundo rustica ) suggest an effect of social GM transmission among adults forming social pair s, as well as trans - generational transmission from a social mother to her own nestlings. At the same time, we observed differ ing GM in adults and nestlings, with no dramatic change in GM with nestling age, a process previously recognised in mammals. Part of the GM detected appears to remain stable over time , and is therefore su itable for further detailed study. To conclude, our studies demonstrate that s ongbird GM differs from that of mammals and that the factors influencing GM composition appear to differ from those in mammals , thereby highlighting the importance of study ing mu ltiple vertebrate groups (not just mammals ) when...
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Diversity of ciliates of the family Nyctotheridae in cockroaches
Soviš, Matyáš ; Čepička, Ivan (advisor) ; Škaloud, Pavel (referee)
Cockroaches are tremendously interesting group of insects with broad morphological diversity and a wide range of lifestyles. They are known to host a plethora of fascinating protists ranging from excavate flagellates through gregarines and amoebozoans to extraordinary ciliates of the group Armophorea. There is however, in contrast to the flagellates, only scarce information on these intestinal ciliates. The available data are mostly only morphological and there is a limited information on their host specificity. Therefore, we chose to inspect the diversity of ciliates in cockroaches, both in the stock cultures of Department of Zoology on Charles University as well as in those collected in nature. We studied their presence in various cockroach lineages, obtained 18S rRNA gene sequence data, and assessed their phylogenetic relationships. We also performed protargol staining of the cells to characterize the morphology of individual lineages.
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