• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 3
  • 1
  • 1
  • Tagged with
  • 6
  • 6
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 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

Molecular markers of ecotoxicological interest in the rainbowfish Melanotaenia fluviatilis

Ponza, Pattareeya, pattareeya.pon@biotec.or.th January 2007 (has links)
The Crimson-spotted rainbowfish (Melanotaenia fluviatilis) from the Murray-Darling basin of Australia is a common indicator species in Australian ecotoxicology. Biochemical changes have been investigated in this species, but not molecular markers of ecotoxicological interest. In this study genes of M. fluviatilis were isolated using a cDNA library and sequences analysed. Of 345 randomly selected clones, 94 shared similarity with 26 different genes in other organisms in public databases. Amongst these, reproductive genes coding for vitellogenin, retinol binding protein, sialyltransferase and zona pellucida protein were considered of interest in ecotoxicology. The vitellogenin gene was selected for study as it has been widely used as a molecular marker of exposure to 17â-estradiol (E2) in teleosts. Gene expression was examined via northern blot, RT-PCR and Real-Time PCR relative to the housekeeping gene (18S rRNA). The expression of vitellogenin mRNA was observed a t 12 hours post-exposure, peaked at 48 hours according to northern blot analysis; and cleared within 4 days, partly consistent with RT-PCR. However, Real-time PCR yielded an inconclusive result, probably due to differences between pooled and individual samples. Vitellogenin in blood plasma was confirmed by western blot, found to be significantly increased and retained in the plasma in fish treated with E2 compared to controls. It was concluded that vitellogenin mRNA is a molecular marker of exposure to 17â-estradiol in the rainbowfish, and could potentially be used as a marker of exposure to environmental estrogenic chemicals. Further investigations of the expression of genes in the cDNA library, could establish other molecular markers of ecotoxicological interest in M. fluviatilis.
2

Expansion of the Genetic Code to Include Acylated Lysine Derivatives and Photocaged Histidine

Kinney, William D 01 January 2019 (has links)
The genetic code of all known organisms is comprised of the 20 proteinogenic amino acids that serve as building blocks on a peptide chain to form a vast array of proteins. Proteins are responsible for virtually every biological process in all organisms; however, the 20 amino acids contain a limited number of functional groups that often leaves much to be desired. The lack of diversity addresses the need to increase the genetic repertoire of living cells to include a variety of amino acids with novel structural, chemical, and physical properties not found in the common 20 amino acids. In order to expand the chemical scope of the genetic code beyond the functionalities that can be directly genetically encoded, unnatural amino acids must be added to the proteome. The ability to incorporate unnatural amino acids (UAAs) into proteins at defined sites has a direct impact on the ability of scientists to study biological processes that are difficult or impossible to address by more classical methods. The UUAs of interest are acylated lysine derivatives (isovaleryl, isobutyryl, and β-hydroxybutyryl) and photocaged histidine. Acylation of histone lysine has been linked to epigenetic regulation of metabolism.1 A means to site-specifically incorporate each acylated lysine derivative would help study the effect of acylated lysine in epigenetic regulation. Likewise, in order to elucidate the role of histidine in specific protein functions, one can replace a critical histidine with a photocaged histidine. Photocaged amino acids are those that possess a photo-cleavable, aromatic caged group. Light-induced protein activation allows for the biological activity of the protein to be spatiotemporally regulated under non-invasive external control.2 The site-specific in vivo incorporation of unnatural amino acids is made possible by amber codon suppression by an orthogonal suppressor aminoacyl-tRNA synthetase (aaRS)/tRNA pair.3 In amber codon suppression the amber stop codon is decoded for an UAA by a suppressor aaRS/tRNA pair. To accept the UAA, the aaRS must be evolved to achieve orthogonal activity with specific UUAs. The pyrrolysyl aaRS/tRNA (PylRS/PylT) pair from M. barkeri and M. mazei was used to construct multiple, large-scale aaRS mutant libraries where critical residues within the active site of PylRS are mutated via site-saturated mutagenesis.4 The libraries were subjected to directed evolution through a series of positive and negative selections to enrich aaRS variants that exclusively bind to acylated lysine derivatives and photocaged histidine as substrates.5 The PylRS selection survivors were screened for UAA activity and identified successful clones underwent a fluorescent activity assay. The active aaRS were used for amber codon suppression to express the respective UAA in ubiquitin and green fluorescent protein constructs.
3

Efeitos BiolÃgicos e CaracterizaÃÃo Inicial da PeÃonha da Serpente Philodryas Nattereri Steindachner 1870 / Biological Effects and Initial Characterization of Snake Venom Philodryas Nattereri Steindachner 1870

Marinetes Dantas de Aquino Nery 14 November 2012 (has links)
nÃo hà / A peÃonha da serpente Philodryas nattereri à uma mistura de proteÃnas e peptÃdeos tÃxicos com diversas aÃÃes locais e sistÃmicas importantes, similares Ãs que ocorrem nos acidentes botrÃpicos. Os mecanismos envolvidos nas aÃÃes locais e sistÃmicas desta peÃonha sÃo pouco conhecidos. O objetivo deste trabalho foi estudar os efeitos renais, cardiovasculares, citotÃxicos e a identificaÃÃo molecular da peÃonha bruta. O teor proteÃco total da peÃonha foi de 85-90% de proteÃnas. Foram utilizados ratos Wistar nos experimentos de perfusÃo de rim isolado, em que o orgÃo foi perfundido com a peÃonha da serpente Philodryas nattereri em diversas concentracÃes para se determinar as possÃveis alteraÃÃes em parÃmetros funcionais, alÃm de alteraÃÃes vasculares em anel de aorta e pressÃo arterial. A peÃonha foi utilizada em cÃlulas epiteliais de tÃbulos renais de cachorro (MDCK) e macrÃfago peritonial de rato (RAW) e mensurada por pletismografia. O edema de pata, as contorÃÃes abdominais e a injeÃÃo intramuscular foram realizados em camundongos Swiss. A peÃonha foi testada em cepas de bactÃrias Escherichia coli, Pseudomonas aeruginosa, Salmonella choleraesuis subsp, Staphylococcus aureus e as culturas foram diluidas 100x. Para a determinaÃÃo do nÃmero de cromossomos da serpente Philodryas nattereri e Philodryas olfersil, utilizou-se uma cultura temporÃria de leucÃcitos. Da glÃndula de Duvernoy construiu-se uma Biblioteca de cDNA com o objetivo de identificar seus genes. A peÃonha bruta foi submetida a RMN (RessonÃncia MagnÃtica Nuclear). Os resultados encontrados demonstraram que a peÃonha da Philodryas nattereri promoveu alteraÃÃes em todos os parÃmetros renais estudados, principalmente na diminuiÃÃo da pressÃo renal (PP) e da resistÃncia vascular renal (RVR), assim como um aumento do fluxo urinÃrio (FU) e do ritmo de filtraÃÃo glomerular (RFG). O resultado mais relevante à que essa peÃonha à altamente lesiva aos tÃbulos renais, sendo tal fato comprovado com a reduÃÃo do percentual de transporte dos eletrÃlitos de sÃdio (Na+), (K+) e cloreto (CIÂ) nas concentraÃÃes estudadas, independente da reduÃÃo da PP. O clearance osmÃtico e as alteraÃÃes nos glomÃrulos e tÃbulos com material proteÃco e hemorrÃgico. As lesÃes foram observadas por anÃlise histolÃgica, mediante indÃcios de apoptose/ necrose e verificadas na cultura das cÃlulas MDCK. A reduÃÃo da pressÃo arterial e da frequÃncia cardiaca parecem estar relacionadas ao relaxamento de vasos renais, cujos efeitos vasodilatadores foram comprovados nos protocolos de anel de aorta. A peÃonha da Philodryas nattereri parece comprometer os tÃbulos renais, independentemente das aÃÃes vasculares. O edema de pata causado pela peÃonha atingiu o mÃximo 2 horas apÃs a inoculaÃÃo e foi inibido pelo dexametasona e o soro anti-bothrops jà a indometacina nÃo foi capaz de interferir significativamente no edema. A injeÃÃo intramuscular de 50μg da peÃonha produziu efeitos de desorganizaÃÃo das fibrilas musculares, hemorragia interfibrilar, edema infiltrado inflamatÃrio e mionecrose dos tipos coagulativa e miolÃtica. Verificou-se que estas alteraÃÃes diminuiram com o passar do tempo. As contorÃÃes abdominais causadas pela peÃonha parecem ser tÃo agressivas quanto o acido acÃtico quando comparado ao controle salino. A atividade da peÃonha em cultura de bactÃrias foi significante para as culturas S. aureus, P. aeruginosa e Salmomela entretanto nÃo apresentou significÃncia para E. Coli. As serpentes Philodryas nattereri e Philodryas olfersii possuem um nÃmero de cromossomos 2n = 36. Da extraÃÃo do RNAtotal da glÃndula da peÃonha, junto com a enzima transcriptase reversa in vitro produziu-se RNAm transcrito a partir de vÃrios genes diferentes. Assim, os DNAc clonados constituem uma biblioteca de cDNA com uma coleÃÃo de genes. Os resultados espectrofotÃmÃtrico de RMN da peÃonha bruta da serpente Philodryas nattereri revelaram na identificaÃÃo da presenÃa de acoplamentos 13C, !H por comprimento de onda de rÃdio. / A peÃonha da serpente Philodryas nattereri à uma mistura de proteÃnas e peptÃdeos tÃxicos com diversas aÃÃes locais e sistÃmicas importantes, similares Ãs que ocorrem nos acidentes botrÃpicos. Os mecanismos envolvidos nas aÃÃes locais e sistÃmicas desta peÃonha sÃo pouco conhecidos. O objetivo deste trabalho foi estudar os efeitos renais, cardiovasculares, citotÃxicos e a identificaÃÃo molecular da peÃonha bruta. O teor proteÃco total da peÃonha foi de 85-90% de proteÃnas. Foram utilizados ratos Wistar nos experimentos de perfusÃo de rim isolado, em que o orgÃo foi perfundido com a peÃonha da serpente Philodryas nattereri em diversas concentracÃes para se determinar as possÃveis alteraÃÃes em parÃmetros funcionais, alÃm de alteraÃÃes vasculares em anel de aorta e pressÃo arterial. A peÃonha foi utilizada em cÃlulas epiteliais de tÃbulos renais de cachorro (MDCK) e macrÃfago peritonial de rato (RAW) e mensurada por pletismografia. O edema de pata, as contorÃÃes abdominais e a injeÃÃo intramuscular foram realizados em camundongos Swiss. A peÃonha foi testada em cepas de bactÃrias Escherichia coli, Pseudomonas aeruginosa, Salmonella choleraesuis subsp, Staphylococcus aureus e as culturas foram diluidas 100x. Para a determinaÃÃo do nÃmero de cromossomos da serpente Philodryas nattereri e Philodryas olfersil, utilizou-se uma cultura temporÃria de leucÃcitos. Da glÃndula de Duvernoy construiu-se uma Biblioteca de cDNA com o objetivo de identificar seus genes. A peÃonha bruta foi submetida a RMN (RessonÃncia MagnÃtica Nuclear). Os resultados encontrados demonstraram que a peÃonha da Philodryas nattereri promoveu alteraÃÃes em todos os parÃmetros renais estudados, principalmente na diminuiÃÃo da pressÃo renal (PP) e da resistÃncia vascular renal (RVR), assim como um aumento do fluxo urinÃrio (FU) e do ritmo de filtraÃÃo glomerular (RFG). O resultado mais relevante à que essa peÃonha à altamente lesiva aos tÃbulos renais, sendo tal fato comprovado com a reduÃÃo do percentual de transporte dos eletrÃlitos de sÃdio (Na+), (K+) e cloreto (CIÂ) nas concentraÃÃes estudadas, independente da reduÃÃo da PP. O clearance osmÃtico e as alteraÃÃes nos glomÃrulos e tÃbulos com material proteÃco e hemorrÃgico. As lesÃes foram observadas por anÃlise histolÃgica, mediante indÃcios de apoptose/ necrose e verificadas na cultura das cÃlulas MDCK. A reduÃÃo da pressÃo arterial e da frequÃncia cardiaca parecem estar relacionadas ao relaxamento de vasos renais, cujos efeitos vasodilatadores foram comprovados nos protocolos de anel de aorta. A peÃonha da Philodryas nattereri parece comprometer os tÃbulos renais, independentemente das aÃÃes vasculares. O edema de pata causado pela peÃonha atingiu o mÃximo 2 horas apÃs a inoculaÃÃo e foi inibido pelo dexametasona e o soro anti-bothrops jà a indometacina nÃo foi capaz de interferir significativamente no edema. A injeÃÃo intramuscular de 50μg da peÃonha produziu efeitos de desorganizaÃÃo das fibrilas musculares, hemorragia interfibrilar, edema infiltrado inflamatÃrio e mionecrose dos tipos coagulativa e miolÃtica. Verificou-se que estas alteraÃÃes diminuiram com o passar do tempo. As contorÃÃes abdominais causadas pela peÃonha parecem ser tÃo agressivas quanto o acido acÃtico quando comparado ao controle salino. A atividade da peÃonha em cultura de bactÃrias foi significante para as culturas S. aureus, P. aeruginosa e Salmomela entretanto nÃo apresentou significÃncia para E. Coli. As serpentes Philodryas nattereri e Philodryas olfersii possuem um nÃmero de cromossomos 2n = 36. Da extraÃÃo do RNAtotal da glÃndula da peÃonha, junto com a enzima transcriptase reversa in vitro produziu-se RNAm transcrito a partir de vÃrios genes diferentes. Assim, os DNAc clonados constituem uma biblioteca de cDNA com uma coleÃÃo de genes. Os resultados espectrofotÃmÃtrico de RMN da peÃonha bruta da serpente Philodryas nattereri revelaram na identificaÃÃo da presenÃa de acoplamentos 13C, !H por comprimento de onda de rÃdio.
4

In Vivo RNAi Rescue in Drosophila melanogaster with Genomic Transgenes from Drosophila pseudoobscura

Schnorrer, Frank, Tomancak , Pavel, Schönbauer, Cornelia, Ejsmont, Radoslaw K., Langer, Christoph C. H. 10 December 2015 (has links) (PDF)
Background Systematic, large-scale RNA interference (RNAi) approaches are very valuable to systematically investigate biological processes in cell culture or in tissues of organisms such as Drosophila. A notorious pitfall of all RNAi technologies are potential false positives caused by unspecific knock-down of genes other than the intended target gene. The ultimate proof for RNAi specificity is a rescue by a construct immune to RNAi, typically originating from a related species. Methodology/Principal Findings We show that primary sequence divergence in areas targeted by Drosophila melanogaster RNAi hairpins in five non-melanogaster species is sufficient to identify orthologs for 81% of the genes that are predicted to be RNAi refractory. We use clones from a genomic fosmid library of Drosophila pseudoobscura to demonstrate the rescue of RNAi phenotypes in Drosophila melanogaster muscles. Four out of five fosmid clones we tested harbour cross-species functionality for the gene assayed, and three out of the four rescue a RNAi phenotype in Drosophila melanogaster. Conclusions/Significance The Drosophila pseudoobscura fosmid library is designed for seamless cross-species transgenesis and can be readily used to demonstrate specificity of RNAi phenotypes in a systematic manner.
5

In Vivo RNAi Rescue in Drosophila melanogaster with Genomic Transgenes from Drosophila pseudoobscura

Schnorrer, Frank, Tomancak, Pavel, Schönbauer, Cornelia, Ejsmont, Radoslaw K., Langer, Christoph C. H. 10 December 2015 (has links)
Background Systematic, large-scale RNA interference (RNAi) approaches are very valuable to systematically investigate biological processes in cell culture or in tissues of organisms such as Drosophila. A notorious pitfall of all RNAi technologies are potential false positives caused by unspecific knock-down of genes other than the intended target gene. The ultimate proof for RNAi specificity is a rescue by a construct immune to RNAi, typically originating from a related species. Methodology/Principal Findings We show that primary sequence divergence in areas targeted by Drosophila melanogaster RNAi hairpins in five non-melanogaster species is sufficient to identify orthologs for 81% of the genes that are predicted to be RNAi refractory. We use clones from a genomic fosmid library of Drosophila pseudoobscura to demonstrate the rescue of RNAi phenotypes in Drosophila melanogaster muscles. Four out of five fosmid clones we tested harbour cross-species functionality for the gene assayed, and three out of the four rescue a RNAi phenotype in Drosophila melanogaster. Conclusions/Significance The Drosophila pseudoobscura fosmid library is designed for seamless cross-species transgenesis and can be readily used to demonstrate specificity of RNAi phenotypes in a systematic manner.
6

Moderní přístupy k projektování elektrických zařízení se zaměřením na železniční stavby / Modern approaches to designing electrical equipment with a focus on railway construction

Forejtník, Jan January 2020 (has links)
The topic Modern Approaches to Designing Electrical Equipment with a Focus on Railway Construction responds to the decision of the Government of the Czech Republic to introduce the BIM method for government over-the-counter contracts from 1 January 2022. The government evaluated the BIM method as an effective tool for digitizing the construction industry. The diploma thesis deals with the method of designing high-current equipment, technologies and distribution on railways according to this new method. The work summarizes information about the present method of design, used high-current electrical equipment on the railway, the near and distant future of railway operation, the organization of administration and maintenance of equipment. It discusses the principle of the BIM method and basic software solutions supporting design activities according to this new method. The Promis.e software published by Bentley is also described in detail, which supports the design of electrical equipment for linear structures according to this method. The BIM method is a means of fulfilling the essence of Construction 4.0. It uses uniform data formats, a common data environment, working with non-graphic information. In the second part of the diploma thesis, the drawing documentation for the sample project of high-current distribution of the railway station was prepared. It was first created using AutoCAD software. After that, the sample project demonstrates the basic principles of the BIM method using Promis.e software. Furthermore, this project is evaluated, both methods of design are compared. The procedure of introducing the BIM method for the design of electrical equipment in a specific design company is proposed and other possible steps in working with the Promis.e software are discussed. The way of creating a and adding element libraries is described. At the end of the diploma thesis it is stated that to successfully master the design work according to the BIM method, it is necessary to have experience with design work in the field, know the principles of the BIM method, choose a suitable software solution, continuously and thoroughly manage these tools and train staff. Under these conditions, it will be possible to make full use of the potential of the BIM method.

Page generated in 0.1149 seconds