311 |
Desenvolupament i Aplicació de Bioassaigs per a la Monitorització Ambiental de Lligands del Receptor d’hidrocarburs d’Aril (AhR, Compostos Tipus Dioxina)Olivares Polo, Alba 25 November 2011 (has links)
Els contaminants ambientals capaços d’unir-se al Receptor d’hidrocarburs d’Aril i induir la seva activació ectòpica són molt diversos i es troben àmpliament distribuïts per tota la biosfera. L’exposició continuada a aquest tipus de compostos s’ha vist relacionada amb l’augment de malalties cardiovasculars i càncer, entre d’altres efectes adversos. D’aquesta manera, la seva monitorització en zones amb fonts de contaminación continues és necessària per tal d’assegurar que no es sobrepassen els límits establerts.
La utilització de bioassaigs per a determinar l’activitat tipus dioxina dels contaminants. a més de la seva composició química, permet una valoració més acurada dels riscos que representen. Aquesta tesis presenta com a objectius el disseny i la validació de bioassaigs basats en un llevat recombinant i embrions de peix zebra que permeten, en el cas dels llevat, una valoració ràpida i econòmica i, en el cas de l’embrió de peix zebra, un estudi més complert i amb la possibilitat d’observar efectes adversos directes. Per tal de dur a terme la seva validació. aquests bioassaigs es van utilitzar en diversos estudis medi ambientals de zones possiblement contaminades per compostos tipus dioxina (PAHs, Organoclorats, etc.) que representen les diferents tipus de matrius on es solen trobar aquests contaminants: sediment fluvial (part baixa del riu Ebre, des de l’Embassament de Flix fins a la desembocadura) i marí (Estuari d’Urdaibai), particulat de l’aire (Vall del Po, al nord d’Itàlia) i sòl (residus miners al districte de Datong a Xina). Els resultats d’aquests estudis han permès establir els nivells de contaminació de cada zona així com observar que la resposta obtinguda pels nostres bioassaigs té un perfil similar a l’observada per altres bioassaigs ja establerts així com amb la composició química. A més, destaquen la importància de combinar l’anàlisi química amb l’activitat biològica per tal d’obtenir una informació més complerta sobre compostos que no s’han tingut en compte o que es desconeix la seva presència a les mostres. / Title: Development and application of bioassays for environmental monitoring Aryl hydrocarbon Receptor ligands (AhR, dioxin-like compounds).
Environmental pollutants able to bind and induce ectopic activation of the Aryl hydrocarbon Receptor (AhR) are diverse and widely distributed throughout the biosphere. Continuous exposure to these compounds has been associated with increased cardiovascular disease and cancer, among other effects. Thus, their monitoring in potentially polluted areas is still necessary to ensure that safety limits are not exceeded. The use of bioassays to determine dioxin-like activity, along with chemical analysis, allow an accurate assessment of the risks they represent. This thesis presents the design, objectives and validation of bioassays based on a recombinant yeast and zebrafish embryos that allow, in the case of yeast, a rapid and economic assessment and, in the case of the zebrafish embryo, a more complete one and with the possibility of observing direct effects. To perform validation, these bioassays were used in studies of environmental areas presumably contaminated by dioxin-like compounds (PAHs, Chlorinated, etc..) that represent different types of matrices where these contaminants are found: fluvial sediment (lower part of the river Ebro, from the Flix Dam to the mouth) and marine (estuary Urdaibai), particulate air (Po Valley, northern Italy) and soil (mining waste in the district of Datong in China). The results of these studies have established pollutions levels present in each area and show a correlation with chemical data as well as a similar response between our bioassays and other more standardized. Besides, those results highlight the importance of combining chemical and biological analysis in order to obtain a complete information of the samples.
|
312 |
Exogenous gene expression from heterologous promoters in fish cell culturesSharps, Angela 10 June 1992 (has links)
Cell culture systems have provided many insights into
eukaryotic gene expression and other biochemical
mechanisms. Since the cell represents the smallest living
unit of any organism it provides a desirable in vitro
system, allowing biochemical studies without the complex
physiology of an entire animal. However, processes
involving intracellular mechanisms, such as development,
aging or carcinogenis, eventually require the analysis of
the intact organism. Transgenic animals are a very
promising tool to approach questions of this magnitude.
Fish in general and the zebrafish (Brachydanio rerio) in
particular are an excellent model system for transgenic
research, mainly due to their extramaternal fertilization
and development and their short generation cycle throughout
the year. The recent derivation of zebrafish cell lines has
opened up possibilities for in vitro analysis of this
popular model species, and expression of heterologous genes
under the influence of promoter and other regulatory
nucleic acid aequences. In contrast to mammalian expression
systems, little nucleic acid sequences controlling gene
expression in fish are known. Therefore we examined
mammalian expression systems in fish cells in order to
determine their efficiency quantitatively. Emphasis was
given to zebrafish cultures with the goal of eventually
injecting in vitro manipulated embryo cells into host
embryos and thereby creating transgenic chimera. / Graduation date: 1993
|
313 |
Neural map organization and development in the lateral-line systemPujol Martí, Jesús 02 March 2012 (has links)
Les neurones sensorials projecten al sistema nerviós central
seguint una distribució espacial ordenada, formant mapes neuronals
que representen propietats dels estímuls sensorials i que són
considerats essencials per a la interpretació del món extern. He
utilitzat la línia lateral de la larva del peix zebra com a model
per a l’estudi de l’organització i el desenvolupament dels mapes
neuronals sensorials. Les neurones sensorials de la línia lateral
formen un mapa neuronal topogràfic, anomenat somatotopia, que
representa la posició de l’estímul sensorial. He demostrat que
l’ordre de neurogènesi defineix la somatotopia. A més, he
identificat dues subclasses de neurones sensorials de la línia
lateral que presenten diferències en els seus patrons de projecció
central i en els contactes amb una neurona central: la cèl·lula de
Mauthner. Proposo que aquest dimorfisme és important per a donar
lloc a reaccions comportamentals adients al context sensorial.
També he demostrat una contribució per part de l’ordre de
neurogènesi a la formació del mapa neuronal dimòrfic de la línia
lateral. Finalment, he obtingut resultats que mostren que la
diversitat neuronal i la topologia del mapa observades ocorren amb
normalitat en l’absència d’activitat sensorial.
Page
|
314 |
Analysis of genes implicated in Alzheimer’s disease pathogenesis using Danio Rerio as a model organism.Newman, Morgan January 2008 (has links)
Alzheimer’s disease (AD) is the most prevalent form of dementia. There is considerable evidence that AD is caused by accumulating amyloid beta peptides in the brain, as a result of amyloid precursor protein (APP) cleavage by secretase enzymes. The presenilin proteins are central to the gamma-secretase cleavage of the intramembrane domain of APP. Aberrant splicing and point mutations in the human presenilin genes, PSEN1 and PSEN2, have been linked to familial forms of AD, through aberrant APP cleavage resulting in irregular amyloid beta formation. Paper 1 gives a review of the literature on AD research and how animal models are used to elucidate mechanisms of AD pathogenesis. The zebrafish model is used in this thesis to investigate genes with potential relevance to AD initiation and pathogenesis. Paper 2 demonstrates that lowlevel aberrant splicing of exon 8 in psen1 transcripts in zebrafish embryos produces potent dominant negative effects that increased psen1 transcription, cause a dramatic hydrocephalus phenotype, decreased pigmentation and other developmental defects. Similar effects are also observed after low-level interference with splicing of exon 8 in psen2 transcripts. In paper 3, a microarray analysis was performed to analyse global gene expression changes to illuminate the molecular aetiology of the phenotypic effects described in paper 2. Of the 100 genes that showed greatest dysregulation after psen1 or psen2 manipulation, 12 genes were common to both treatments. Five of these have known function and showed increased expression. Cyclin G1 (ccng1) was of particular interest as the human CCNG1 protein shows increased immunoreactivity in the cytoplasm of neurons in human AD brains. Phylogenetic and conserved synteny analysis confirmed the orthology of zebrafish ccng1 with human CCNG1. Expression of zebrafish ccng1 in developing embryos at 24 hours post fertilization (hpf) was observed in the eye, tectum and somites. Decreased Ccng1 expression does not lead to any developmental defects and also cannot rescue the hydrocephalus or pigmentation phenotypes of embryos with aberrant splicing of psen1 exon 8. An analysis of zebrafish ccng1 function in paper 4 (thesis chapter in the form of a manuscript) indicates that truncation of Ccng1 appears to cause developmental defects in the brain, notochord and somites, however, it does not decrease the level of normal ccng1 transcript. The CCNG1 paralogue, Cyclin G2, (CCNG2), is also expressed in zebrafiish (ccng2). Decreasing the expression of Ccng2 results in similar effects on embryo development as truncating Ccng1. Therefore, the truncated forms of Ccng1 potentially interfere with Ccng2 function in a dominant negative manner. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1342482 / Thesis (Ph.D.) -- University of Adelaide, School of Molecular and Biomedical Science, 2008
|
315 |
Analysis of genes implicated in Alzheimer’s disease pathogenesis using Danio Rerio as a model organism.Newman, Morgan January 2008 (has links)
Alzheimer’s disease (AD) is the most prevalent form of dementia. There is considerable evidence that AD is caused by accumulating amyloid beta peptides in the brain, as a result of amyloid precursor protein (APP) cleavage by secretase enzymes. The presenilin proteins are central to the gamma-secretase cleavage of the intramembrane domain of APP. Aberrant splicing and point mutations in the human presenilin genes, PSEN1 and PSEN2, have been linked to familial forms of AD, through aberrant APP cleavage resulting in irregular amyloid beta formation. Paper 1 gives a review of the literature on AD research and how animal models are used to elucidate mechanisms of AD pathogenesis. The zebrafish model is used in this thesis to investigate genes with potential relevance to AD initiation and pathogenesis. Paper 2 demonstrates that lowlevel aberrant splicing of exon 8 in psen1 transcripts in zebrafish embryos produces potent dominant negative effects that increased psen1 transcription, cause a dramatic hydrocephalus phenotype, decreased pigmentation and other developmental defects. Similar effects are also observed after low-level interference with splicing of exon 8 in psen2 transcripts. In paper 3, a microarray analysis was performed to analyse global gene expression changes to illuminate the molecular aetiology of the phenotypic effects described in paper 2. Of the 100 genes that showed greatest dysregulation after psen1 or psen2 manipulation, 12 genes were common to both treatments. Five of these have known function and showed increased expression. Cyclin G1 (ccng1) was of particular interest as the human CCNG1 protein shows increased immunoreactivity in the cytoplasm of neurons in human AD brains. Phylogenetic and conserved synteny analysis confirmed the orthology of zebrafish ccng1 with human CCNG1. Expression of zebrafish ccng1 in developing embryos at 24 hours post fertilization (hpf) was observed in the eye, tectum and somites. Decreased Ccng1 expression does not lead to any developmental defects and also cannot rescue the hydrocephalus or pigmentation phenotypes of embryos with aberrant splicing of psen1 exon 8. An analysis of zebrafish ccng1 function in paper 4 (thesis chapter in the form of a manuscript) indicates that truncation of Ccng1 appears to cause developmental defects in the brain, notochord and somites, however, it does not decrease the level of normal ccng1 transcript. The CCNG1 paralogue, Cyclin G2, (CCNG2), is also expressed in zebrafiish (ccng2). Decreasing the expression of Ccng2 results in similar effects on embryo development as truncating Ccng1. Therefore, the truncated forms of Ccng1 potentially interfere with Ccng2 function in a dominant negative manner. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1342482 / Thesis (Ph.D.) -- University of Adelaide, School of Molecular and Biomedical Science, 2008
|
316 |
Zebrafish embryos exposed to alcohol undergo abnormal development of motor neurons and muscle fibersSylvain, Nicole J. January 2009 (has links)
Thesis (M. Sc.)--University of Alberta, 2009. / Title from pdf file main screen (viewed on Sept. 22, 2009). "A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Master of Science in Physiology, Cell and Developmental biology, Biological Sciences, University of Alberta." Includes bibliographical references.
|
317 |
Characterizing the role of CECR1 in cat eye syndrome by using mouse modelsYang, Fang. January 2010 (has links)
Thesis (M.Sc.)--University of Alberta, 2010. / A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Master of Science in Molecular Biology and Genetics, Department of Biological Sciences. Title from pdf file main screen (viewed on April 28, 2010). Accompanied by four supplementary video recording files. Includes bibliographical references.
|
318 |
The role and mechanism of BMP-15, activin and TGF-beta in regulating zebrafish oocyte maturation /Tan, Qian. January 2009 (has links)
Thesis (M.Sc.)--York University, 2009. Graduate Programme in Biology. / Typescript. Includes bibliographical references (leaves 53-57). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:MR51603
|
319 |
Altered gene expression a mechanism of reproductive toxicity in zebrafish (Danio rerio) exposed to benzo[a]pyrene /Hoffmann, Jennifer L. January 2004 (has links)
Thesis (Ph. D.)--Miami University, Dept. of Zoology, 2004. / Title from second page of PDF document. Includes bibliographical references (p. 116-127).
|
320 |
In vivo assessment of nanomaterial-induced toxicity using embryonic zebrafish /Usenko, Crystal Y. January 1900 (has links)
Thesis (M.S.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 96-103). Also available on the World Wide Web.
|
Page generated in 0.0481 seconds