Recent genomic data indicate that RNA polymerase II (Pol II) function extends beyond conventional transcription of primarily protein-coding genes. Among the five snRNAs required for pre-mRNA splicing, only the U6 snRNA is synthesized by RNA polymerase III (Pol III). Here we address the question of how Pol II coordinates the expression of spliceosome components, including U6. We used chromatin immunoprecipitation (ChIP) and high-resolution mapping by PCR to localize both Pol II and Pol III to snRNA gene regions. We report the surprising finding that Pol II is highly concentrated ∼300 bp upstream of all five active human U6 genes in vivo. The U6 snRNA, an essential component of the spliceosome, is synthesized by Pol III, whereas all other spliceosomal snRNAs are Pol II transcripts. Accordingly, U6 transcripts were terminated in a Pol III-specific manner, and Pol III localized to the transcribed gene regions. However, synthesis of both U6 and U2 snRNAs was α-amanitin-sensitive, indicating a requirement for Pol II activity in the expression of both snRNAs. Moreover, both Pol II and histone tail acetylation marks were lost from U6 promoters upon α-amanitin treatment. The results indicate that Pol II is concentrated at specific genomic regions from which it can regulate Pol III activity by a general mechanism. Consequently, Pol II coordinates expression of all RNA and protein components of the spliceosome.

This thesis deals with isolation and identification wine yeasts from grapes and must. For analysis was used white wine Sauvignon that was grown and producing after needs ecological agriculture. Remove samples were processed in laboratory and by the help of dilution method were obtained pure culture isolated yeasts. In the following step, by the application of commercial kit UltraCleanTM Microbial DNA Isolation Kit we were able to isolated individual DNA that it was used to the next analysis. Isolated DNA was amplification by PCR method with ITS1 and ITS4 primers. PCR products were detected on agarose gel. Amplification samples were chopped five restriction endonucleases: HaeIII, HinfI, TaqaI, AluI and MseI. Chopped DNA was detected by the same way as PCR products and it was compared with restriction patterns of collection yeasts. In the next step it was compared genetic similarity of isolated yeasts by using BioNumerics software. As a criterion it was used Pearson coefficients and UPGMA clastering analysis. The result is dedrogram of genetics similarity isolated yeasts.

The Carlina vulgaris complex in central Europe includes several lineages defined by their ecology, morphology and distribution. This diploma thesis is focused on relationships between the taxa recognized in the Czech Republic, namely Carlina vulgaris subsp. vulgaris, C. biebersteinii subsp. biebersteinii, C. biebersteinii subsp. brevibracteata and C. biebersteinii subsp. sudetica. Molecular analysis revealed two genetically defined groups. One includes samples from relict populations in western Bohemia and from high mountains classified as C. biebersteinii subsp. biebersteinii and C. biebersteinii subsp. sudetica. The other is represented by plants classified as C. vulgaris and C. biebersteinii subsp. brevibracteata. This genetic differentiation was also confirmed by morphometric analysis. However, relationships within these two groups remain unclear. The Czech populations of Carlina biebersteinii subsp. biebersteinii as well as of C. biebersteinii subsp. sudetica are closely related to the mountain populations in the Alps and Carpathians. Their occurrence in the Czech Republic is relict and they should be in focus of nature conservation. However, the separate taxonomic position of the claimed endemic C. biebersteinii subsp. sudetica is probably unjustified.

In Antarctica, diatoms inhabit multiple limno-terrestrial habitat types, which may each individually offer unique ecological information for use in biomonitoring, paleoecology, and biogeography. However, we are still at the initial exploration stage of documenting the diversity among habitat types from different Antarctic regions, which is necessary to serve as baseline data for the aforementioned scientific disciplines, and ultimately inform conservation decisions. To gain insight into the spatial and habitat controls on Antarctic diatom communities, the importance of habitat type and island aspect was investigated by studying diatoms living in ponds, mosses, streams, and seepage areas on two opposite sides Vega Island, Antarctic Peninsula. A diverse flora of 136 taxa belonging to 31 genera was revealed, which was dominated by the genus Nitzschia, and suggests that the flora of Vega Island is biogeographically influenced by both continental and Maritime Antarctic bioregions. Habitat type was found to be a crucial factor for diatom community composition, and was stronger than the influence of island aspect. In ordination analyses, moss samples were separated primarily by their abundances of the diatom Chamaepinnularia krookiformis, while pond samples were separated by Nitzschia paleacea and stream...

Die vorliegende Arbeit wurde als kumulative Dissertation auf der Grundlage von in international anerkannten Zeitschriften mit Fachgutachtersystem (Peer-review-Verfahren) veröffentlichten Publikationen verfasst. Mit Hilfe eines neuen integrativen Ansatzes aus Morphologie und Molekulargenetik wurden Studien zur intraspezifischen Variabilität einzelner Vertreter der Familie Lymnaeidae (Schlammschnecken) durchgeführt, die Schlussfolgerungen darüber zulassen, welche Wertigkeit den in dieser Gruppe bisher für Taxonomie und Systematik verwendeten morphologischen und anatomischen Merkmalen überhaupt zugemessen werden sollte. Ein weiteres Ziel der Analysen war herauszufinden, inwiefern eigene Rekonstruktionen phylogenetischer Bäume, basierend auf Kern- und Mitochondrienmarkern, bisher bestehende Hypothesen zur Taxonomie und Systematik der Lymnaeidae bestätigen oder widerlegen. Erste eigene molekulargenetisch überprüfte morphologische Analysen bei paläarktischen Vertretern der Gattung Radix zeigen, dass die zur Artdifferenzierung etablierten Merkmale Gehäuseform, Mantelpigmentierung, Längenverhältnis der beiden Abschnitte des männlichen Kopulationsapparates (Praeputium und Phallotheca), Länge des Bursaductes und Form der Bursa copulatrix eine höhere innerartliche Variabilität aufweisen als eigentlich für die einzelnen Arten angenommen wurde. Sie sind, entgegen bisheriger Annahmen, zu einem großen Teil nicht artspezifisch. Molekulargenetisch deutlich unterscheidbare Arten können die gleiche Gehäuseform und Mantelpigmentierung aufweisen und sind oft auch mittels anatomischer Merkmale nicht eindeutig unterscheidbar. Es kann, auch anhand erster eigener Studien an anderen Vertretern der Familie Lymnaeidae, geschlussfolgert werden, dass von den meisten Malakologen bisher in diese Merkmale innerhalb der Schlammschnecken eine Bedeutung für Taxonomie und Systematik hineininterpretiert wurde, die sie offensichtlich auf Grund ihrer hohen Plastizität nicht besitzen. Die molekulargenetischen Methoden eröffnen hier neue Perspektiven für ihre Beurteilung sowie für die objektivere Abgrenzung von Arten und Gattungen. Auf der Basis der neuen Erkenntnisse über die Variabilität morphologischer Merkmale wurde für die mitteleuropäischen Vertreter der Gattung Radix ein neuer Bestimmungsschlüssel erarbeitet, der mehr Radix-Formen als bisher berücksichtigt. Bei molekulargenetischen Untersuchungen an Vertretern der Gattung Stagnicola konnte ein relativ hoher Prozentsatz an Hybridisierung festgestellt werden, was in der Praxis Konsequenzen für die Anwendung des Barcoding mit mitochondrialen Markern (COI und Cytochrom b) hat. / This work was written as cumulative doctoral thesis based on publications in peer reviewed international journals. Aim of the studies was to analyse the range of the intraspecific variability of some representatives of the family Lymnaeidae as well as to find out which value should be given to the morphological and anatomical characters used for taxonomy and systematics at all. For this a new integrative approach of morphology and molecular genetics was sought. It was also important to find out how own reconstructions of phylogenetic trees based on nuclear and mitochondrial markers confirm or refute existing views on taxonomy and systematics of the Lymnaeidae. First own morphological analyses of Palaearctic representatives of the genus Radix checked by molecular genetics reveal that shell morphology, mantle pigmentation, length ratio of Praeputium to penial sheath, length of the duct of the bursa copulatrix and shape of the bursa show more variability in this characteristics as recognised for these species in literature. They are, contrary to previous assumptions, to a large extent not specific for single species. With molecular genetic methods clearly distinguishable species may have the same shell morphology and mantle pigmentation and could be not clearly differentiated by anatomical characters in many cases. It can be concluded, also on the basis of own studies of other representatives of the family Lymnaeidae, that to these characters was given an importance for taxonomy and systematics by most of the malacologists that they obviously do not have because of their high plasticity. Molecular genetic methods allow a new interpretation of the importance of morphological and anatomical characters and a more objective definition of species and genera. Based on the new findings on variability of morphological characters a new determination key for the representatives of the genus Radix in central Europe was elaborated. It enables the determination of more Radix forms than it was previously possible with determination tools. Molecular genetic analyses of representatives of the genus Stagnicola revealed a high percentage of hybridisation. In practise, this has consequences for the application of barcoding on the base of mitochondrial markers (COI and cyt-b).

Title: Using online tools to assigns and assess the work of secondary school pupils in mathematics Author: Jiří Vančura Department: Department of Mathematics Education Supervisor: doc. RNDr. Jarmila Robová, CSc., Department of Mathematics Education Abstract: Despite the long-term trend of technology implementation in mathematics education, there is not much research that would empirically and long-term monitor the impact of technology on pupils' knowledge. The presented three studies examine the potential benefits of using Khan Academy as a tool for assigning and assessing homework in mathematics at upper secondary schools. The studies deal with three groups of research questions. What is the attitude of pupils towards the Khan Academy implementation, and what benefit do they see in the online practice? Can pupils transfer acquired knowledge from Khan Academy to the school context? In addition to procedural knowledge, does Khan Academy develop a deeper understanding of the underlying concepts? At the time of the research, the author was the mathematics teacher of some of the participating pupils. Based on the results of these studies, the consequences and recommendations for teaching mathematics at upper secondary schools using online platforms are discussed at the end of the thesis. Keywords: Khan Academy,...

The aim of this work is to critically review the anatomical and morphological characters being currently used in the determination of Central European species of the genus Anisus and to confront them with molecular characters. For the molecular analysis mitochondrial genes for 16S rRNA and cytochrome c oxidase - subunit I (COI) were used. DNA analysis showed that known species occuring in the Czech Republic form well distinguishable genetic lines. Subsequent revisions of the anatomical characters of these lines have proven that these characters are due to their variability not suitable for determination, especially for the differentiating of the species A. spirorbis and A. leucostoma. The conchological characters have proven more suitable, especially the ratio of the size of the last and penultimate whorl. With the help of this character, we can safely determine a population within which there are transitional forms in other morphological and anatomical characters.

This thesis is focused in the representatives of beetle families Hydrophilidae and Hydraenidae of West Indies and adjacent regions. It consists of two parts, the phylogenetic part and the systematic part. The phylogenetic part focuses on the hydrophilid genera Phaenonotum and Crenitulus of Greater Antilles: beetles were sampled in all four main islands (Cuba, Hispaniola, Puerto Rico and Jamaica) and analyzed using the combination of molecular and morphological data. The genus Phaenonotum contains four single-island endemics, of which those from Cuba, Jamaica and Hispaniola are wingless and form a clade that diversified ca. 46 million years ago (Ma) and likely colonized the Caribbean via the GAARlandia land bridge. In contrast, the Puerto Rican endemic and the two remaining non-endemic species colonized the Greater Antilles by over- water dispersal during the Oligocene-Miocene. The analysis of the genus Crenitulus revealed that Greater Antillean species belong to two separate clades: the Crenitulus yunque clade endemic for Cuba and Hispaniola, and the Crenitulus suturalis clade containing specimens from Greater Antilles and from northern America. A detailed revision of the Crenitulus yunque clade using morphology and molecular-based species delimitation recognized 11 species locally endemic for...

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

While it is now widely accepted that new firms growth is essential for the foundation of economic dynamism, knowledge about this early growth is still scattered. Indeed, very little is known about how new firms grow and develop over time. What types of distinct growth patterns do those firms exhibit? How do these growth patterns and corresponding firms differ from each others in terms of development and strategic choices? To better understand the process of new firm growth, recent entrepreneurship research stresses that there is a strong need for a new conceptual scheme and new longitudinal research methods. This is actually one of the main entrepreneurship research challenges. In this context, our aim is to provide new insights regarding the process of new firm growth. In this research, we develop and test an original methodology allowing the empirical taxonomy of early growth trajectories across multiple sectors, integrating both the multidimensional and dynamic aspects of growth. Our approach applies principal component and cluster analysis to a large sample of firms, using financial and demographic data collected over time to identify in a systematic way distinct growth stages. We use then sequence analysis and a Markov chain approach to extract and compare the trajectories of individual firms over time. This allows the identification of a limited number of typical growth trajectories, which are adopted by the majority of firms in our sample. Finally, internal replication is performed to validate the growth trajectories identified and bivariate analysis is used to examine the link between the identified growth trajectories and the demographic characteristics of the corresponding firms. We have applied our methodology to a sample of 741 Belgian firms created between 1992 and 2002 and which have grown above micro-firm size. Our approach allowed identifying four distinct growth stages and seven typical growth trajectories, which remain valid for the six first years of the majority of the firms in our sample. This taxonomy of early growth trajectories is consistent with individual patterns already identified in the literature and appears not to be sector-dependent. The major contribution of this doctoral thesis is that, based on empirical evidence, early growth appears to be neither a continuous (or life cycle based) nor idiosyncratic (or completely random) process. It can be adequately described through a limited number of typical growth trajectories, valid across sectors. Thus, our research brings insight regarding how new firm evolve over time and therefore contributes to our understanding and appreciation of the heterogeneity of the growth trajectory phenomenon. Next, our research provides also an original methodological approach allowing the systematic analysis of growth trajectories, which deals with key limitations identified in the literature regarding the need for a multidimensional and dynamic study of growth across multiple sectors. Our findings indicate that this novel systematic approach is useful for taxonomy development and therefore contributes to reduce the gap between the complexity of new firm growth process and the standard approaches often mobilised to deal with it. Finally, while our findings provide empirical and methodological support in early development of new firms study, they also provide many implications to entrepreneurial research and practices. Further researches are needed to improve our understanding of the dynamic growth process of new ventures. It should explore which endogenous and exogenous factors might explain why a majority of start-ups follow the seven identified typical growth trajectories. It could be also highly relevant to refine our taxonomy by examining the relationship between innovative and technological sources and growth trajectories, both in high and low technological industries. Finally, we should test the accuracy of the proposed taxonomy across countries as well as beyond the early stage of new firm development.