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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Evoluce Vicia cracca L. - distribuce cytotypů, jejich genetická variabilita a růstové charakteristiky / Evolution of Vicia cracca L. - distribution of cytotypes, their genetic variation and growth traits

Eliášová, Anežka January 2018 (has links)
A lot of the research has been made in the field of plant polyploidy since the discovery of this phenomenon. However, the more we know, the more questions arise. Overall, the most insistent questions remain: How did the polyploids arise and become established? Is it advantageous to be polyploid? We chose a perennial herb Vicia cracca L. to study the causes and consequences of polyploidisation on microevolution of a diploid-tetraploid complex in central European conditions. First, evidence from both flow cytometry and molecular markers (allozymes, DNA sequences, microsatellites) confirmed a hypothesised autopolyploid origin of tetraploids. Based on allozymes, we proved that tetraploids are genetically richer than diploid ancestors. However, we showed that the conclusions depend on statistics used for genetic variation measurements. Nevertheless, tetraploids of V. cracca suffered lesser reduction in seed production after artificial selfing than diploids. We thus infer that they profit from multiple allele dosage, which can mask deleterious alleles. We also corroborated an existence of a central European contact zone of diploids and tetraploids and discovered two other contact zones in south-western and south- eastern Europe. The central European contact zone with several mixed-ploidy populations served us as...
82

Co stojí za evoluční explozí diverzity terestrických vodomilů? / Understanding the biodiversity boom in terrestrial hydrophilid beetles

Arriaga Varela, Emmanuel January 2019 (has links)
The research contained in this thesis explores the phylogenetic systematics, taxonomy, evolution and biogeography of tribe Megasternini (Coleoptera: Hydrophilidae: Sphaeridiinae). Megasternines are an oustandingly diverse group of terrestrial water scavenger beetles with almost 600 described species and probably up to 1,000 species in total. Its species can be found in a wide array of habitats with abundant decaying material like humid leaf litter, dung, rotten cacti, beach wrack, flowers, etc. The specific and ecological diversity as well as their global distribution makes Megasternini an interesting model group for the understanding of processes underlying the diversification, biogeography and evolution of beetles. The scientific part of the thesis contains seven papers: three published, one accepted, one submitted and two manuscripts. Chapters 1-4 are focused on the taxonomy of selected groups. These chapters aim to cover a variety of cases in terms of biogeography (the Greater Antilles, northern Neotropics, Africa and Southeast Asia), ecology (species associated with leaf litter, dung, flower and rotten cacti) and different taxonomic scenarios. One new extant genus and eight new extant species are described in these chapters. Chapter 5 is a revision of all known hydrophilid fossils from Baltic...
83

Evoluce morálky, morálka evoluce, aneb, Frans de Waal, Richard Dawkins a teorie dvojí dědičnosti / Evolution of Morality, Morality of Evolution

Šafránek, Jakub January 2010 (has links)
The goal of this work is to present attitudes of two contemporary authors who are in the center of the evolutionary-origin-of morality debate, that is theories of Richard Dawkins and Frans de Waal. The critical reflection of their works on this topic will center around the building blocks of morality and the supposed "moral sense", which according to the dutch primatologist humans to some extent share with some of their living evolutinary relatives. In case of Richard Dawkins we are about to review his meme theory and parasytical character of some elements of culture. Morevoer there will be presented accounts of the dual inheritance theorists, which in authors opinion can reunite both presented authors and thier attitudes, i.e. put the parasytic/independent character of memes in accordance with the building blocks of morality approach. This approach in turn can explain many phenomena of human contemporary morals and their limits. Keywords: Morality, evolution, dual inheritance theory, coevolution, memes
84

Evoluce mechanismů homeostáze auxinu / The evolution of auxin homeostasis mechanisms

Skokan, Roman January 2021 (has links)
The evolution of auxin homeostasis mechanisms Ph.D. thesis Roman Skokan, 2021 Abstract The streptophyte lineage consists of land plants (embryophytes) and several groups of primarily freshwater green algae called charophytes. While the phytohormone auxin is a conserved regulator of land plant development, little has been known of the possible origins of auxin response mechanisms in charophytes. We found that one of these mechanisms, the cellular auxin efflux via the PIN family of transport proteins, is most likely a deeply conserved feature in streptophytes. Additionally, we investigated the state of conservation in the green lineage (Viridiplantae) of the gene families known to be involved in auxin transport in land plants. We revealed that some families are deeply conserved outside land plants, but not others. We also helped uncover a unique radiation within the PIN family in Charophyceae. Striving to uncover the native significance of auxin transport in charophytes, we discovered a growth response to exogenously-applied auxin in Closterium, though the effort to produce stable mutant lines in the native PIN homolog is still underway. Altogether, we brought important insights into the evolution of auxin transport and response in the streptophyte lineage, though many questions still remain.
85

Porovnání genetické variability geograficky vzdálených populací vybraných evropských mořských druhů hlaváčů / Comparison of the genetic variability of geographically distant populations of selected species of European marine gobies

Chalupecká, Katarína January 2018 (has links)
Gobies (Gobiidae, Actinopterygii) are small, predominantly cryptic, marine, brackish and freshwater fishes. They abundantly inhabit coastal waters, although their occurrence is far from being mapped due to their inconspicity, often hidden lifestyle and a lack of commercial use. Information about distribution of many species is therefore still rather poor. Many species are known only from a few locations scattered throughout the Mediterranean Sea and the Atlantic. This suggests that most species could actually have a relatively continuous distribution area. Comparing the genetic variability of geographically distant populations of the same species can help to detect whether there is some population subdivision and whether populations are genetically isolated from each other. The aim of my thesis was to compare genetic variability of the populations of eight goby species: Corcyrogobius liechtensteini, Gobius cruentatus, Gobius geniporus, Gobius incognitus, Chromogobius quadrivittatus, Chromogobius zebratus, Millerigobius macrocephalus and Zebrus zebrus within Mediterranean Sea and north-eastern Atlantic Ocean. Samples used in this work were collected from two Atlantic (Spain and Portugal) and seven Mediterranean localities (France, Sicily, Croatia, Montenegro, Greece, and Cyprus - northern and...
86

Evoluce Vicia cracca L. - distribuce cytotypů, jejich genetická variabilita a růstové charakteristiky / Evolution of Vicia cracca L. - distribution of cytotypes, their genetic variation and growth traits

Eliášová, Anežka January 2018 (has links)
A lot of the research has been made in the field of plant polyploidy since the discovery of this phenomenon. However, the more we know, the more questions arise. Overall, the most insistent questions remain: How did the polyploids arise and become established? Is it advantageous to be polyploid? We chose a perennial herb Vicia cracca L. to study the causes and consequences of polyploidisation on microevolution of a diploid-tetraploid complex in central European conditions. First, evidence from both flow cytometry and molecular markers (allozymes, DNA sequences, microsatellites) confirmed a hypothesised autopolyploid origin of tetraploids. Based on allozymes, we proved that tetraploids are genetically richer than diploid ancestors. However, we showed that the conclusions depend on statistics used for genetic variation measurements. Nevertheless, tetraploids of V. cracca suffered lesser reduction in seed production after artificial selfing than diploids. We thus infer that they profit from multiple allele dosage, which can mask deleterious alleles. We also corroborated an existence of a central European contact zone of diploids and tetraploids and discovered two other contact zones in south-western and south- eastern Europe. The central European contact zone with several mixed-ploidy populations served us as...
87

Proteomická a funkční charakterizace izoforem PsbO / Proteomic and functional characterization of PsbO isoforms

Duchoslav, Miloš January 2012 (has links)
PsbO (manganese-stabilizing protein) is the largest extrinsic protein of photosystem II, located on the lumen side of photosystem. It is present in all known oxyphototrophic organisms. PsbO facilitates photosynthetic water splitting, which takes place in an oxygen evolving center (Mn4CaO5 cluster) of photosystem II. This work is focused on PsbO of higher plants and its isoforms, particularly their evolution and functions. Bioinformatic analyses revealed that majority of higher plants express exactly two psbO isoforms. A phylogenetic tree of PsbO sequences has an unusual topology. The two paralogous isoforms do not diverge at the base of the phylogenetic tree, as anticipated, but rather at the end of particular branches, at the level of family or lower taxonomic unit. In this work we propose and discuss several hypotheses concerning evolution of PsbO isoforms. The work further includes detailed analysis and identification of protein spots assigned to PsbO on 2D IEF-SDS PAGE gels of potato thylakoid proteins. We identified predominant version of PsbO isoform in most of the spots. We did not succeed to find any posttranslational modification. We optimized a method of psbO expression in E. coli and subsequent purification, which yielded relatively big amount of properly folded recombinant protein. Analysis of...
88

Strukturní charakterizace vybraných náhodných proteinových sekvencí s vysokým obsahem neuspořádanosti / Structural characterization of selected random protein sequences with high disorder content

Ptáčková, Barbora January 2018 (has links)
An infinitesimal fraction of the practically infinite sequence space has achieved enormous functional diversity of proteins during evolution. Intrinsically disordered proteins (IDPs) which lack a fully defined three-dimensional structure are the most likely precursors to today's proteins because of their flexible conformation and functional diversity. But how have these proteins evolved into often rigid and highly specialized protein structures? This evolutionary trajectory has the greatest support in the theory of induced fold whereby the development of the structure was mediated by the interaction and coevolution of primordial unstructured proteins with different cofactors or RNA molecules. Although some random sequences from the sequence space which is not used by nature are also able to form folded proteins the more suitable candidates for evolution of structure and function appear to be random sequences with a high content of disordered which have low aggregation propensity. The selected random protein sequences with high disorder content have been structurally characterized in this work for their further use in evolutionary studies. Three artificial proteins were selected from a random-sequence library based on previous study in our laboratory. In the present work they were purified and...
89

Transformace / Transformation

ZAPLETALOVÁ, Petra January 2013 (has links)
Abstract The thesis consists of two parts: theoretical and practical. In the theoretical part of my thesis I would like to describe the development of art, especially the prehistoric times, the specifics of the time and gradual changes, focusing on the life of prehistoric creatures and their development. Zoom personalities related to this topic, especially illustrators, painters, filmmakers, who are involved in public awareness about the picture of the time. Finally, I would like to mention the influence of authors and styles of the 20th century and approached the work of contemporary artists inspired by this theme. In the practical part of the thesis, deals with the presentation selected and died out creatures. To this I would like to take the theoretical and practical knowledge based on my work involved.
90

Transgenerační epigenetická dědičnost u savců / Transgenerational Epigenetic Inheritance in Mammals

Dostálová, Veronika January 2017 (has links)
Transgenerational epigenetic inheritance in mamals is a widely discussed topic in today's biology. Epigenetic modifications are molecules that play a crucial role in regulation of gene transcription. Epigenetic modifications regulate another epigenetic modification's establishment. The extrinsic and the intrinsic cellular or organismal environment is involved within the establishment of epigenetic state. The molecules involved in epigenetic processes are able to regulate gene transcription in reaction to the environment and therefore these molecules partly shape the phenotype. Most importantly, epigenetic processes are affected by cellular or organismal history. A question emerges: Are these molecules able to transfer information through germline to subsequent generations? Does transgenerational epigenetic inheritance in mammals exist? Experimental data show it is so. What consequences this can mean in our understanding of evolution? Powered by TCPDF (www.tcpdf.org)

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