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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.
21

Aplicação de tecnicas avançadas de espectrometria de massas em ciencias de alimentos e perfumaria / Advanced mass spectrometry techniques applied in food analysis and perfume characterization

Marques, Lygia de Azevedo 28 July 2006 (has links)
Orientador: Marcos Nogueira Eberlin / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-07T11:19:58Z (GMT). No. of bitstreams: 1 Marques_LygiadeAzevedo_M.pdf: 2432568 bytes, checksum: 7bf6003b0fa0df13e1ba0f91d7ebf00b (MD5) Previous issue date: 2006 / Resumo: Neste trabalho aplicamos técnicas avançadas de espectrometria de massas, (MALDI-TOF e ESI-MS) na análise de micotoxinas em alimentos e na tipificação e verificação de fraudes em perfumes. Aplicamos a técnica MALDI-TOF em análises de micotoxinas, e esta mostrou excelente desempenho nas análises de aflatoxinas e ocratoxina e vantagem sobre a técnica de escolha atual, o método ELISA. Esta vantagem é principalmente maior especificidade através de maior exatidão em medidas de massas e, portanto, maior confiabilidade. O Planejamento de experimento foi uma ferramenta valiosa para obtenção das melhores condições e estudo dos parâmetros de interferência. O limite de detecção encontrado para a técnica foi da ordem de 25 pg para aflatoxinas e de 1 ng para ocratoxina, com perspectiva de melhoria através de aumento da massa amostral em estudos futuros para adaptação da metodologia de extração na matriz de interesse à técnica MALDI-TOF. A técnica ESI-MS foi utilizada para a tipificação e detecção de perfumes proporcionando, através da análise de componentes principais (PCA), a diferenciação com segurança entre perfumes originais, falsos e inspirados, utilizando como indicadores componentes polares não majoritários característicos de cada categoria avaliada. Este estudo abre caminho para que esta técnica seja utilizada na avaliação de perfumes que estão sob suspeita de falsificação com auxilio de uma biblioteca de "fingerprint" de perfumes por ESI-MS. O emprego da técnica de MALDI-TOF também é uma opção vantajosa para o monitoramento da qualidade de grãos quanto a presença de toxinas indesejáveis, bem como ameaças de bioterrorismo. / Abstract: In this work we applied advanced mass spectrometry techniques (MALDI-TOF and ESI-MS) to micotoxin analysis in food and for the typification and detection of counterfeit perfumes. MALDI-TOF was applied to micotoxin analysis, which showed excellent performance for the analysis of aflatoxins and ochratoxin with advantage over the current technique of choice, the ELISA method. This advantage is mainly its greater specifity due the exactness of the measurements, therefore with higher reliability. The surface analysis was a valuable tool to attain the best conditions and study the interference of several parameters. The detection limit found for the technique was 25 pg for aflatoxins and 1 ng for ochratoxins, with perspective of improvement through increase of the sample mass in future studies for adaptation of the methodology of extration in the matrix of interest for the MALDI-TOF technique. The ESI-MS technique was used for typification and detection of counterfeit perfumes, providing, through principal component analysis (PCA), the characterization of original, counterfeit and inspired perfumes, using as minoritarian polar compounds as diagnostic ions of each perfume category evaluated. We envisage that the method can be used to establish a ESI-MS fingerprinting library of perfumes for comparison with those from samples under investigation, and that such a library could be updated constantly by the addition of ESI-MS of new perfumes even before they are commercially released. MALDI-TOF technique is also an advantageous option for the monitoring of crop quality relating to the presence of undesirable toxins, as well as bioterrorism threats by micotoxin poisoning. / Mestrado / Quimica Analitica / Mestre em Química
22

Comparative evaluation of the extraction and analysis of urinary phospholipids and lysophospholipids using MALDI-TOF/MS / MALDI-TOF/MSを用いた尿中リン脂質およびリゾリン脂質の抽出法および分析法に関する比較検討

Li, Xin 26 July 2021 (has links)
京都大学 / 新制・課程博士 / 博士(医学) / 甲第23410号 / 医博第4755号 / 新制||医||1052(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 村川 泰裕, 教授 長尾 美紀, 教授 柳田 素子 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM
23

Vliv složení kultivačního média na hmotnostní spektra kvasinek druhů Cryptococcus laurentii a Cryptococcus flavescens / Effect of medium composition on the mass spectra of the yeast species of Cryptococcus laurentii and Cryptococcus flavescens

Ledvina, Vojtěch January 2015 (has links)
Cryptococcus laurentii and Cryptococcus flavescens are nonfermenting yeasts forming extracellular polysaccharide capsule. Both species are mainly saprofytic but Cr. laurentii is also known to be an opportunistic pathogen in immunocompromised patients. Cr. flavescens used to be considered a synonym of Cr. laurentii but nowadays it is classified as a separate species that belongs to the phylogenetic group I of the Cr. laurentii group. In the experimental part 28 strains of species Cr. laurentii, Cr. flavescens a Cr. victoriae were biotyped using MALDI-TOF MS. The yeasts were cultivated on three different media (Sabouraud, YPD and potato agar) and three methods were used for the protein extraction. The impact of growth medium composition from which the strains were inoculated on the quality of spectra was studied together with the suitability of individual methods for use on different media. Then the impact of growth medium composition on the quality of acquired spectra was evaluated. Finally, all strains were compared mutually and with the type strain of Cr. laurentii CCY 17 3-2. The composition of the medium cells were inoculated from was found to have little impact on the spectra quality. The same result was determined for the composition of the actual growth medium cells were cultivated on. Crucial for the quality of mass spectrum is the method of cells preparation. Best results were acquired when cultivating cells on YPD agar, washing the cells with ethanol and using mix of sinapinic and ferulic acid as a matrix. Potato agar was found not suitable for cultivating yeasts of the Cryptococcus genus due to significant production of extracellular polysaccharides which complicate the protein isolation process. All strains were compared to Cr. laurentii type strain CCY 17-3-2 and MSP dendrograms were created based on the spectra similarity. In the MSP dendrograms all strains were successfully divided into relevant species on all tested media. Finally sequences of D1/D2 domain of LSU gene were compared and phylogenetic tree was created. This tree was then compared to the MSP dendrograms.
24

Separace hepcidinu na magnetických sorbentech s následnou analýzou pomocí MALDI-TOF-MSí / Separation of hepcidin using magnetic sorbents with subsequent MALDI-TOF MS analysis

Vávrová, Jana January 2010 (has links)
Hepcidin is cysteine-rich cationic peptide produced by hepatocytes, secreted into blood plasma, and excreted in urine. Hepcidin is proposed to be the key regulator of iron metabolism and an evaluation of changes in the hepcidin level is important for diagnosis of several diseases. However, methods used for the hepcidin detection and determination in urine and serum have certain limitations. At present time MALDI-TOF MS based approaches have been applied for final analysis of urinary and/or serum hepcidin levels. Before MS analysis, separation of hepcidin from analyzed samples is an important and necessary step. The aim of this study was to compare the ability of several magnetic sorbents with different coating matrix and/or different terminal functionalized groups to adsorb hepcidin prior MS analysis. Either commercial magnetic sorbents containing -COOH groups or magnetic hydrophilic IDA-modified polymethacrylate microparticles P(HEMA-co-GMA)-IDA with immobilized metal ions were use for this purpose. Hepcidin was adsorbed to magnetic sorbents containing linked carboxyl groups (i.e. to weak cation exchange magnetic particles) at pH 6.8 independently on a nature of magnetic particle coating layer. Magnetic particles P(HEMA-co- GMA)-IDA with immobilized Cu(II) ions were found to adsorb hepcidin in a...
25

Development and evaluation of MALDI-TOF MS-based serotyping for Streptococcus pneumoniae / MALDI-TOF MSを用いた肺炎球菌莢膜型決定法の開発およびその性能評価

Nakano, Satoshi 23 March 2016 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第19576号 / 医博第4083号 / 新制||医||1013(附属図書館) / 32612 / 京都大学大学院医学研究科医学専攻 / (主査)教授 中川 一路, 教授 岩田 想, 教授 西渕 光昭 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM
26

Structural Studies of Oligosaccharides Attached to Proteins Expressed in Different Organisms and PEGylation of a non-Glycosylated Protein

Motari, Edwin Mwamba 26 August 2010 (has links)
No description available.
27

Identification des arthropodes vecteurs et des micro-organismes associés par MALDI-TOF-MS / Identification of arthropods vectors and associated micro-organisms by MALDI-TOF MS

Yssouf, Amina 06 October 2014 (has links)
Les arthropodes vecteurs sont hématophages et peuvent assurer la transmission biologique active d'un agent pathogène responsable de maladies humaines ou animales. La lutte anti-vectorielle et la surveillance épidémiologique des vecteurs sont essentielles dans la stratégie de lutte contre les maladies vectorielles. Disposer d'outils d'identification précis, fiable et rapides des vecteurs et des pathogènes associés est indispensable. Ainsi dans ce projet nous avons évalué l'utilisation du MALDI-TOF MS pour identifier les arthropodes vecteurs ainsi que la détection des pathogènes associés. La première partie de notre travail consistait à utiliser MALDI TOF pour identifier les tiques, moustiques et les puces. Nous avons déterminé quelle partie du spécimen permettait d'obtenir une reproductibilité des spectres et une identification correcte par des tests à l'aveugle après création d'une base de données de référence. La deuxième partie consistait à utiliser le MALDI-TOF MS pour détecter des Rcikettsies associés aux tiques dont Rickettsia conorii et R. slovaca, deux pathogènes humains transmis respectivement par Rhipicephalus sanguineus et Dermacentor marginatus. Des variations spectrales étaient obtenues entre les spécimens infectés et non infectés, avec des masses spécifiques liés à l'infection des tiques par les rickettsies. La technique d'identification était validée par des tests à l'aveugle. Les résultats obtenus permettent de conclure que le MALDI TOF pourra être utilisé dans l'avenir pour identifier les tiques prélevées chez des patients, les arthropodes vecteurs lors des enquêtes entomologiques et préciser la prévalence d'infection de ces arthropodes. / Arthropods are vectors bloodsucking and can ensure the active biological transmission of a pathogen responsible of human or veterinary diseases. The vector control and vectors epidemiological surveillance are essential in the strategy against the vectors-borne diseases. Accurate, reliable and rapid identification of vectors and associated pathogens are essential. Thus, in this project we evaluated the use of MALDI-TOF MS for the arthropods vectors identification as well as for the detection of associated pathogens. This proteomics technology emerged since few years ago and is currently used in routine for bacteria identification in many microbiology laboratories. In the first part of our work, we used the MALDI TOF to identify the tick, mosquito and flea species. For each arthropod, we determined which part allowed obtaining reproducible spectra by MALDI TOF and correct identification by blind test, after reference database creation. The second part consisted to use the MALDI-TOF MS to detect the associated Rickettsia in ticks including Rickettsia conorii and R. slovaca, two human pathogens transmitted by Rhipicephalus sanguineus and respectively Dermacentors marginatus. The spectral variations were obtained between infected and non infected specimens with specific masses related to the tick infection by Rickettsia. The identification technique of not or infected ticks was validated by blind tests. The obtained results allowed concluding that the MALDI-TOF MS could be used in the future to identify the ticks removed from patient, the arthropods vectors and during entomological survey and determine the prevalence of infection of these arthropods.
28

Estudo dos perfis de N-glicosilação da prolactina recombinante humana expressa em células humanas HEK293 / Study of N-glycosylate profiles of human recombinant prolactin expressed in human cells HEK293

Silva, Felipe Douglas 30 July 2018 (has links)
A prolactina humana (hPRL) é um hormônio sintetizado pela hipófise com inúmeras funções tais como: lactação, reprodução e regulação osmótica. Este hormônio é frequentemente dosado em casos de problemas na lactação, infertilidade, além de estudos que elucidam sua ligação em alguns tipos de câncer (mama, próstata e útero). A hPRL é encontrada na forma não glicosilada (NG-hPRL) (23 kDa) e glicosilada (G-hPRL) (25 kDa), sendo a isoforma glicosilada um modelo ideal de análise de perfil de N-glicanos, já que possui um único sítio de glicosilação localizado na Asparagina 31. A glicosilação está relacionada diretamente à solubilidade, à estabilidade, ao enovelamento, à meia-vida e atividade biológica in vivo. As células de ovário de hamster chinês (CHO) e as células embrionárias de rim humano (HEK293) são os hospedeiros mais utilizados para expressão de proteínas recombinantes, já que podem ser cultivadas em altas densidades e por possuírem similaridade nas modificações pós-traducionais. O objetivo foi expressar, purificar e realizar uma caracterização físico-química e biológica da hPRL glicosilada de células HEK293, incluindo análise da estrutura de carboidratos. Para tanto, foi realizada uma transfecção em células HEK293T (aderidas) com o vetor pcDNA 3.4-TOPO. Foi obtida uma expressão de 21,26 ± 8,3 μg/mL de hPRL no meio condicionado sem soro. A hPRL foi purificada por cromatografia de afinidade a metais imobilizados (IMAC), eluindo 92% da hPRL em uma única fração que, analisada por HPSEC, apresentou pureza de 97%. O perfil de N-glicanos da amostra apresentou seis espécies, todas com terminação em ácido-siálico, do tipo complexo, sendo bi, tri e tetra-antenárias, com relativa predominância da espécie N2G2S1 (29,4%). A bioatividade in vitro da G-hPRL HEK293 demonstrou ser ≅ 16 vezes menor que a G-hPRL produzida em células CHO. / Human prolactin (hPRL) is a hormone synthesized by the pituitary gland with innumerable functions such as lactation, reproduction and osmotic regulation. This hormone is often determined in cases of lactation problems, infertility, and studies that elucidate its connection in some types of cancer (breast, prostate and uterus). The hPRL is found in the non-glycosylated (NG-hPRL) (23 kDa) and glycosylated (G-hPRL) (25 kDa) form, being the glycosylated isoform an ideal model for N-glycan profile analysis, since it has a single glycosylation site located in Asparagine 31. Glycosylation is directly related to solubility, stability, folding, half-life and biological activity in vivo. Chinese hamster ovary (CHO) cells and human embryonic kidney (HEK293) cells are the most widely used hosts for expression of recombinant proteins, since they can be grown at high densities and have similarity in post-translational modifications. The objective of this work was to express, purify and perform a physicochemical and biological characterization of the glycosylated hPRL from HEK293 cells, including analysis of the carbohydrate structure. For this purpose, a transfection was performed on HEK293T (adhered) cells with the 3.4-TOPO pcDNA vector. Expression of 21.26 ± 8.3 μg/mL hPRL in the serum free conditioned medium was obtained. The hPRL was purified by immobilized metal affinity chromatography (IMAC), eluting 92% of the hPRL in a single fraction which analyzed by HPSEC, showed 97% purity. The N-glycans profile of the sample showed six species, all with sialic acid termination, complex type, being bi, tri and tetra antennary, with a relative predominance of N2G2S1 (29.4%). In vitro bioactivity of G-hPRL HEK293 demonstrated to be ≅ 16-fold lower than G-hPRL produced in CHO cells.
29

Artidentifiering av mögelsvamp med MALDI-TOF MS / Species identification of filamentous fungi with MALDI-TOF MS

Leander, Ellinor January 2018 (has links)
Snabb och korrekt artidentifiering är avgörande för effektiv behandling av svampinfektioner, särskilt bland immunsupprimerade patienter. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) används rutinmässigt på kliniska laboratorier för identifiering av karaktäristiska proteinmönster hos bakterier och jästsvampar genom tolkning av proteinspektra i en masspektradatabas för korrekt artidentifiering. Mögelsvamparnas hårda cellvägg och heterogena växtsätt med varierande proteinuttryck beroende på mognadsstadie, försvårar identifiering med MALDI-TOF MS. Metodens tänkbara fördelar mot traditionella metoden mikroskopering är förkortade svarstider, säkrare artidentifiering av fler arter och mindre beroende av subjektiv morfologisk bedömning. Studiens syfte var att undersöka om MALDI-TOF MS kunde anpassas och användas för identifieringen av mögelsvamp i klinisk rutindiagnostik. Fyra referensstammar (Aspergillus niger, A. fumigatus, A.terreus, A.flavus) och ett kliniskt isolat (A.terreus) undersöktes. Preparationsmetoderna (I) fullständig myrsyraextraktion, (II) direktapplicering och (III) suspension i destillerat vatten användes för analys av sporer och frontmycel hos yngre och äldre mögelkulturer. Två olika masspektradatabaser för artidentifiering jämfördes; rutindatabasen BDAL och den specialiserade mögeldatabasen Filamentous Fungi Library. Även plocktekniken av mögelmaterial inför analys med MALDI-TOF MS utvärderades. Vid vissa tillfällen förbättrades artidentifieringen efter extraktion av mögelkulturerna, medan i andra fall var direktapplicering fullt tillräcklig. Mögelmaterial med mycket sporer tenderade ge något fler artidentifieringar i BDAL oavsett kulturernas ålder.  Filamentous Fungi Library tenderade i vissa fall ge bättre resultat jämfört med BDAL för yngre kulturer. Fler studier krävs för att utvärdera och optimera MALDI-TOF MS som metod för artidentifiering av mögelsvamp. / Rapid and accurate species identification is crucial for successful treatment of fungal infections, especially among immunosuppressed patients. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) is used routinely at clinical laboratories to identify characteristic protein patterns of bacteria and yeast by the interpretation of protein spectra in a database for accurate species identification. The hard cell wall of the mold and the heterogeneous growth with varying protein expression due to maturation, complicates identification with MALDI-TOF MS. The potential benefits of this method compared to microscopy as traditional method are shortened turn-around times, safer species identification of more species that is independent on subjective morphological assessment. The purpose of the study was to investigate whether MALDI-TOF MS could be adapted and used for the identification of molds in clinical routine diagnostics. Four reference strains (Aspergillus niger, A.fumigatus, A.terreus, A.flavus) and a clinical isolate (A.terreus) were examined. The preparation methods (I) complete formic acid extraction, (II) direct application and (III) suspension in distilled water were used for analysis of spores and frontmycelium from younger and older mold cultures. Two different masspektradatabases for species identification were compared; routine database BDAL and the specialized mold database, Filamentous Fungi Library. Also the collecting technique of mold prior to analysis with MALDI-TOF MS was evaluated. Sometimes, the species identification improved after extraction of mold cultures, while in other cases direct application was sufficient. Cultures with a lot of spores tended to give slightly more species identifications in BDAL regardless of the age of cultures. Filamentous Fungi Library, in some cases, tended to improve the performance compared to BDAL for younger cultures. More studies are required to evaluate and optimize MALDI-TOF MS as a method of mold identification.
30

Estudo dos perfis de N-glicosilação da prolactina recombinante humana expressa em células humanas HEK293 / Study of N-glycosylate profiles of human recombinant prolactin expressed in human cells HEK293

Felipe Douglas Silva 30 July 2018 (has links)
A prolactina humana (hPRL) é um hormônio sintetizado pela hipófise com inúmeras funções tais como: lactação, reprodução e regulação osmótica. Este hormônio é frequentemente dosado em casos de problemas na lactação, infertilidade, além de estudos que elucidam sua ligação em alguns tipos de câncer (mama, próstata e útero). A hPRL é encontrada na forma não glicosilada (NG-hPRL) (23 kDa) e glicosilada (G-hPRL) (25 kDa), sendo a isoforma glicosilada um modelo ideal de análise de perfil de N-glicanos, já que possui um único sítio de glicosilação localizado na Asparagina 31. A glicosilação está relacionada diretamente à solubilidade, à estabilidade, ao enovelamento, à meia-vida e atividade biológica in vivo. As células de ovário de hamster chinês (CHO) e as células embrionárias de rim humano (HEK293) são os hospedeiros mais utilizados para expressão de proteínas recombinantes, já que podem ser cultivadas em altas densidades e por possuírem similaridade nas modificações pós-traducionais. O objetivo foi expressar, purificar e realizar uma caracterização físico-química e biológica da hPRL glicosilada de células HEK293, incluindo análise da estrutura de carboidratos. Para tanto, foi realizada uma transfecção em células HEK293T (aderidas) com o vetor pcDNA 3.4-TOPO. Foi obtida uma expressão de 21,26 ± 8,3 μg/mL de hPRL no meio condicionado sem soro. A hPRL foi purificada por cromatografia de afinidade a metais imobilizados (IMAC), eluindo 92% da hPRL em uma única fração que, analisada por HPSEC, apresentou pureza de 97%. O perfil de N-glicanos da amostra apresentou seis espécies, todas com terminação em ácido-siálico, do tipo complexo, sendo bi, tri e tetra-antenárias, com relativa predominância da espécie N2G2S1 (29,4%). A bioatividade in vitro da G-hPRL HEK293 demonstrou ser ≅ 16 vezes menor que a G-hPRL produzida em células CHO. / Human prolactin (hPRL) is a hormone synthesized by the pituitary gland with innumerable functions such as lactation, reproduction and osmotic regulation. This hormone is often determined in cases of lactation problems, infertility, and studies that elucidate its connection in some types of cancer (breast, prostate and uterus). The hPRL is found in the non-glycosylated (NG-hPRL) (23 kDa) and glycosylated (G-hPRL) (25 kDa) form, being the glycosylated isoform an ideal model for N-glycan profile analysis, since it has a single glycosylation site located in Asparagine 31. Glycosylation is directly related to solubility, stability, folding, half-life and biological activity in vivo. Chinese hamster ovary (CHO) cells and human embryonic kidney (HEK293) cells are the most widely used hosts for expression of recombinant proteins, since they can be grown at high densities and have similarity in post-translational modifications. The objective of this work was to express, purify and perform a physicochemical and biological characterization of the glycosylated hPRL from HEK293 cells, including analysis of the carbohydrate structure. For this purpose, a transfection was performed on HEK293T (adhered) cells with the 3.4-TOPO pcDNA vector. Expression of 21.26 ± 8.3 μg/mL hPRL in the serum free conditioned medium was obtained. The hPRL was purified by immobilized metal affinity chromatography (IMAC), eluting 92% of the hPRL in a single fraction which analyzed by HPSEC, showed 97% purity. The N-glycans profile of the sample showed six species, all with sialic acid termination, complex type, being bi, tri and tetra antennary, with a relative predominance of N2G2S1 (29.4%). In vitro bioactivity of G-hPRL HEK293 demonstrated to be ≅ 16-fold lower than G-hPRL produced in CHO cells.

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