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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.
1

Unearthing the genome of the earthworm Lumbricus rubellus

Elsworth, Benjamin Lloyd January 2013 (has links)
The earthworm has long been of interest to biologists, most notably Charles Darwin, who was the first to reveal their true role as eco-engineers of the soil. However, to fully understand an animal one needs to combine observational data with the fundamental building blocks of life, DNA. For many years, sequencing a genome was an incredibly costly and time-consuming process. Recent advances in sequencing technology have led to high quality, high throughput data being available at low cost. Although this provides large amounts of sequence data, the bioinformatics knowledge required to assemble and annotate these new data are still in their infancy. This bottleneck is slowly opening up, and with it come the first glimpses into the new and exciting biology of many new species. This thesis provides the first high quality draft genome assembly and annotation of an earthworm, Lumbricus rubellus. The assembly process and resulting data highlight the complexity of assembling a eukaryotic genome using short read data. To improve assembly, a novel approach was created utilising transcripts to scaffold the genome (https://github.com/elswob/SCUBAT). The annotation of the assembly provides the draft of the complete proteome, which is also supported by the first RNA-Seq generated transcriptome. These annotations have enabled detailed analysis of the protein coding genes including comparative analysis with two other annelids (a leech and a polychaete worm) and a symbiont (Verminephrobacter). This analysis identified four key areas which appear to be either highly enhanced or unique to L. rubellus. Three of these may be related to the unique environment from which the sequenced worms originated and add to the mounting evidence for the use of earthworms as bioindicators of soil quality. All data is stored in relational databases and available to search and browse via a website at www.earthworms.org. It is hoped that this genome will provide a springboard for many future investigations into the earthworm and continue research into this wonderful animal.
2

Mitochondrial genomics and northwestern Atlantic population genetics of marine annelids /

Jennings, Robert M. Unknown Date (has links)
Thesis (Ph. D.)--Joint Program in Biological Oceanography (Massachusetts Institute of Technology, Dept. of Biology; and the Woods Hole Oceanographic Institution), 2005. / Includes bibliographical references.
3

THE CYTOCHROME P450 SUPERFAMILY COMPLEMENT (CYPome) IN THE ANNELID CAPITELLA TELETA

Dejong, Christopher A. January 2013 (has links)
<p>CYPs are a large and diverse protein superfamily found in all domains of life and are able to metabolize a wide array of both exogenous and endogenous molecules. The CYPome of the polychaete annelid Capitella teleta has been robustly identified and annotated with the genome assembly available (version 1). Annotation of 84 full length and 12 partial CYP sequences predicted a total of 96 functional CYPs in C. teleta. A further 13 CYP fragments were found but these may be pseudogenes. The C. teleta CYPome contained 24 novel CYP families and seven novel CYP subfamilies within existing families. A phylogenetic analysis was completed, primarily with vertebrate sequences, and identified that the C teleta sequences were found in 9 of the 11 metazoan CYP clans. Clan 2 was expanded in this species with 51 CYPs in 14 novel CYP families containing 20 subfamilies. There were five clan 3, four clan 4, and six mitochondrial clan full length CYPs. Two CYPs, CYP3071A1 and CYP3072A1, did not cluster with any metazoan CYP clan. C. teleta had a CYP51A1 gene with ~65% identity to vertebrate CYP51A1 sequences and was predicted to have lanosterol 14 α-demethylase activity. Several CYPs (CYP376A1, CYP3068A1, CYP3069A1, and CYP3070A1) are discussed as candidate genes for steroidogenesis. There are two CYP1-like CYPs and a total of four CYP331s found in C. teleta, which may play a role in PAH metabolism and warrant further analysis.</p> / Master of Science (MSc)
4

Molekulární charakterizacevybraných obranných faktorů v čeledi Lumbricidae / Molekulárna charakterizácia vybraných obranných faktorov v čeľadi Lumbricidae

Mančíková, Veronika January 2011 (has links)
Earthworms belonging to oligochaete annelids have been a model for comparative immunology for over 40 years. They possess various defense mechanisms efficiently recognizing and responding to non-self substances. Among these there are molecules with many biological activities including cytolytic, antimicrobial and proteolytic. This work is aimed to compare the immunological features of two closely related earthworm species Eisenia andrei and Eisenia fetida. Due to many morphological and life cycle similarities they have been, until recently, regarded as members of subspecies. Interestingly, their natural habitat varies considerably, and it was of particular interest to investigate how these environmental differences affect the features of innate immunity of both species. Key words: annelids, innate immunity, Eisenia andrei, Eisenia fetida, CCF, fetidin, lysenin, lysozyme
5

Modélisation des changements spatio-temporels des communautés de macroinvertébrés benthiques dans les rivières d'Asie et d'Europe / Modelling spatio-temporal changes of benthic macroinvertebrate communities in Asian and European rivers

Sor, Ratha 10 July 2017 (has links)
Objectifs généraux: les systèmes fluviaux tropicaux et tempérés d'eau douce sont connus pour soutenir différentes communautés biotiques. Dans cette étude, menée dans une région d'Asie tropicale et dans une région d'Europe tempérée, j'ai étudié la composition et la diversité de la communauté des macro-invertébrés benthiques ainsi que leurs variations spatiales et temporelles. J'ai également examiné les influences des variables physico-chimiques de la qualité de l'eau sur les variations et la diversité de la composition de la communauté et j'ai modélisé l'occurrence d'espèces sélectionnées. Localisation géographique: Asie tropicale: le bassin aval du Mékong (LMB), couvrant une superficie de 609 000 km2; Europe tempérée: Europe occidentale, fleuves flamands (Belgique), couvrant une superficie de 13 787 km2. Matériel et méthodes: Pour le LMB, les données recueillies de 2004 à 2008 ont été utilisées et les valeurs médianes de cette période ont été analysées. Pour les rivières flamandes, les données collectées de 1991 à 2010 ont été utilisées. Les données ont été divisées en 4 périodes: D1: 1991-1995, D2: 1996-2000, D3: 2001-2005 et D4: 2006-2010. Les médianes de chaque période ont été utilisées pour des analyses spatiales détaillées. Des analyses multivariées ont été appliquées pour relier la composition et la diversité de la communauté aux variables physico-chimiques. Cinq techniques de modélisation, à savoir la régression logistique (LR), les Random Forest (RF), le Support Vector Machine (SVM), les réseaux de neurones artificiels (ANN) et les arbres de classification (CT) ont été utilisées pour modéliser l'occurrence desespèces sélectionnées. Principaux résultats: Variations de la composition des communautés, diversité et relation avec les variables environnementales Dans le cours aval du Mékong LMB, 299 taxons de macro-invertébrés distribués dans 196 genres et 90 familles ont été identifiées; dont 131 insectes, 98 mollusques, 38 crustacés et 32 annélides. / Overall aims: Freshwater tropical and temperate river systems are known to support different biotic communities. In this study, I investigated benthic macroinvertebrate community composition and diversity and its spatial and temporal variation both in tropical Asian and temperate European regions. I also examined the influences of physical-chemical water quality variables on community composition, variations and diversity, and modelled the occurrence of selected species. Locations: Tropical Asia: the Lower Mekong Basin (LMB), covering an area of 609,000 km2; Temperate Europe: Western Europe, Flemish rivers (Belgium), covering an area of 13,787 km2. Materials and Methods: For the LMB, data collected from 2004 to 2008 were used, and median values of this period were analysed. For Flemish rivers, data collected from 1991 to 2010 were used. The data were divided into 4 periods: D1: 1991-1995, D2: 1996-2000, D3: 2001-2005 and D4: 2006-2010. The medians of each period were used for detailed spatial analyses. Multivariate analyses were applied to relate community composition and diversity to physical-chemical variables. Five modelling techniques namely Logistic Regression (LR), Random Forest (RF), Support Vector Machine (SVM), Artificial Neural Network (ANN) and Classification Tree (CT) were used to model the occurrence of selected species. Main results: Community composition variations, diversity and relationship with environmental variables From the LMB, 299 macroinvertebrate taxa belonging to 196 genera and 90 families were identified: 131 insects, 98 molluscs, 38 crustaceans, and 32 annelids.
6

Výuka kroužkovců na Podkrušnohorském gymnáziu (případová studie) / Teaching of Annelids in Podkrušnohorské gymnázium (The Case Study)

Sládek, Josef January 2016 (has links)
The main object of this thesis is to evaluate the results of a case study of teaching the topic of annelids. The study was carried for three years at Podkušnohorské gymnasium grammar school in Most. Another objective is to find the connection between obtained data, activity of students during classes and other chosen factors that may affected a success in the classified test and post-test. The thesis is divided into two parts. First part presents the research part which is devoted to a brief overview of textbooks for second grade of elementary and high school. The second, analytical part, is divided into three subsections. The first subsection is devoted to the evaluation of teaching methods for individual teachers Most schools with an emphasis on the level of activity of students in biology classes. The second subsection analyzes the results of the investigation and commented the results on, especially the success rate of students in the various test phases. The third subsection suggests, based on the data obtained, the best teaching methods to the topic of annelids. Key words: annelids, pupils, pre-test, classification, activity during lesson, knowledge extinction, teacher

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