• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 165
  • 69
  • 55
  • 35
  • 24
  • 20
  • 19
  • 17
  • 12
  • 6
  • 2
  • 2
  • Tagged with
  • 450
  • 244
  • 195
  • 144
  • 129
  • 52
  • 49
  • 46
  • 44
  • 38
  • 36
  • 34
  • 32
  • 30
  • 27
  • 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.
161

La palytoxine chez les Zoantharia (Cnidaria) : biodiversité des organismes producteurs et activité anticancéreuse de la toxine / Palytoxin from Zoantharia (Cnidaria) : biodiversity of producer organisms and toxin anticancer activity

Sawelew, Ludovic 02 October 2017 (has links)
Cette thèse confidentielle public/privé porte sur l’étude des sources biologiques de la palytoxine (PlTX) dont l’identification est nécessaire afin de développer un protocole industriel standardisé permettant d’obtenir des quantités importantes de toxine pour réaliser diverses études. Premièrement, l’activité anticancéreuse in vitro de la PlTX a été évaluée sur des lignées cellulaires cancéreuses humaines et murines. La cytotoxicité de la PlTX est 106 fois plus importante sur les lignées cancéreuses par rapport aux lignées non cancéreuses témoins. La PlTX utilisée a été purifiée à partir d’une espèce encore non décrite de Palythoa, qui a été caractérisée phylogénétiquement et morphologiquement et qui fournit les quantités de PlTX pures les plus élevées à ce jour (2,8 ± 0,45 mg/g de matière fraîche). La localisation de la PlTX dans les tissus de cette espèce a été décrite par des techniques innovantes d’imagerie par spectrométrie de masse MALDI. Deuxièmement, une étude phylogénétique et une quantification de la PlTX par HPLC chez 29 échantillons de Zoantharia a été réalisée. La spectrométrie de masse ESI a permis de donner la structure chimique du type de PlTX purifiée à partir de ces échantillons. La dernière partie présente une étude préliminaire sur la culture ex hospite des endosymbiotes unicellulaires de Palythoa spp. appartenant au genre Symbiodinium afin de tester leur implication dans la synthèse de PlTX. En conclusion, il ressort que la PlTX présente un effet anticancéreux très prometteur. Le moyen le plus efficace actuellement pour obtenir de la PlTX en quantité importante est de l’extraire à partir d’une espèce de Palythoa caractérisée grâce à ce travail. / The work presented in this manuscript is the outcome of a confidential public/private collaboration. It concerns the study of biological sources of PlTX. Their identification is required to develop an industrial-standard protocol in order to obtain sufficient quantity of toxin to perform several studies. In the first part, the in vitro anti-cancer activity of PlTX was evaluated upon several human and murine cancerous cell lines. The cytotoxic activity of PlTX was 106-times more powerful against cancerous lines compared to non-cancerous control lines. The PlTX used in this work was purified from an undescribed species of Palythoa which was characterized based on phylogenetic and morphological analyses. This species produces the highest PlTX levels ever recorded (2.8 ± 0.45 mg/g fresh matter). PlTX localization in tissues of this Palythoa species was also described by innovative MALDI mass spectrometry imaging techniques. The second part presents a phylogenetic study of 29 samples of Zoantharia and quantification of PlTX by HPLC. The ESI-mass spectrometry allowed to characterize the chemical structure of the type of PlTX purified from these samples. The last part of this thesis constitutes a preliminary study on the ex hospite culture of unicellular endosymbionts belonging to the genus Symbiodinium. Ensosymbiont cells were isolated from Palythoa species containing high PlTX concentrations in order to test their implication in PlTX synthesis. In conclusion, PLTX has a very promising anticancer activity, and the best way to obtain large quantities of PlTX is the extraction from a Palythoa species characterized in this work.
162

Potencial metabólico de fungos endofíticos de plantas do gênero Anthurium da Ilha de Alcatrazes / Metabolic potential of endophytic fungi of plants of the genus Anthurium from Alcatrazes Island

Sergio Birello Sartori 07 October 2016 (has links)
Fungos endofíticos estão presentes em plantas de diversos ambientes e produzem compostos com amplas propriedades químicas e aplicações, tanto na área médico-farmacológica quanto na agronômica. Entretanto, ainda há muito a ser investigado sobre seu potencial biotecnológico, principalmente em locais pouco explorados. As ilhas apresentam um ambiente particular e altamente vulnerável, tornando-as locais promissores na busca de organismos pouco comuns ou ainda endêmicos. Sendo assim, neste trabalho foi realizado o isolamento e estudo químico e biológico de fungos endofíticos isolados de 2 espécies plantas do gênero Anthurium da Ilha de Alcatrazes-SP. Para isto, fragmentos foliares das plantas A. loefgrenii (HRCB 46467) e A. alctrazense (HRCB 46465 - endêmica da ilha) foram inoculados em 10 meios de cultivo com diferentes composições, resultando no isolamento de 106 fungos endofíticos. Por meio de análises químicas por MALDI-TOF-MS e ensaio biológico contra fitopatógenos, foram selecionados 3 fungos para estudo. Estes foram identificados por técnicas morfológicas e moleculares como sendo Penicillium citrinum (P2MSF2F3), Penicillium simplicissimum (P210-4F2) e Aureobasidium melanogenum (P7AF2F3). No estudo dos metabólitos secundários de P. citrinum foi isolado o composto citrinina, o qual apresentou atividade inibitória do crescimento micelial dos fitopatógenos Colletotrichum gloeosporioides (MIC= 125 μg mL-1), Colletotrichum lindemuthianum (MIC= 0,48 μg mL-1), Phomopsis sojae (MIC= 250 μg mL-1) e Fusarium oxysporum f. sp. phaseoli (MIC= 125 μg mL-1). Outras frações obtidas do meio metabólico de P. citrinum (fração F3a3 e citrinina) apresentaram atividade inibitória (100% de inibição) à formas promastigotas de Leishmania infantum. No estudo dos metabólitos secundários de P. simplicissimum foi obtida a fração F2b, ativa contra L. infantum (100% de inibição), da qual foram isolados os compostos andrastina A e penicisoquinolina, sendo o primeiro relato de sua produção por esta espécie, além de outros 5 compostos ainda não identificados. No estudo dos metabólitos secundários de A. melanogenum foi isolado o composto metil-orselinato, relatado pela primeira vez para este fungo. Do mesmo fungo foi obtida a fração F1d2l ativa contra L. infantum (100% inibição), da qual foram isolados 2 compostos ainda não identificados. Este é o primeiro relato de fungos isolados de antúrios da ilha de Alcatrazes, bem como do estudo de seus metabólitos secundários. Este trabalho apresenta contribuição no conhecimento sobre fungos endofíticos e seu potencial metabólico, com aplicações nas áreas agronômica e médico-farmacológica. / Endophytic fungi are present in plants in various environments and produce compounds with wide chemical properties and applications, both in the medical and in agronomic field. However, much remains to be investigated about their biotechnological potential, especially in unexplored places. Islands have a particular and highly vulnerable environment, making them promising sites in search of unusual or endemic organisms. Thus, this work represents the isolation and chemical and biological study of endophytic fungi isolated from 2 species of plants of the genus Anthurium of Alcatrazes island-SP. For this, leaf fragments from plants A. loefgrenii (HRCB 46467) and A. alcatrazense (HRCB 46465 - endemic plant from the Island) were inoculated onto 10 culture media with different composition, resulting in the isolation of 106 endophytic fungi. Three strains were selected to be studied through chemical analysis by MALDI-TOF-MS and bioassay against phytopathogens. These were identified by morphological and molecular techniques as Penicillium citrinum (P2MSF2F3), Penicillium simplicissimum (P210-4F2) and Aureobasidium melanogenum (P7AF2F3). In the study of secondary metabolites of P. citrinum it was isolated the compound citrinin, which showed inibitory activity against the plant pathogens Colletotrichum gloeosporioides (MIC= 125 μg mL-1), Colletotrichum lindemuthianum (MIC= 0.48 μg mL-1), Phomopsis sojae (MIC= 250 μg mL-1) and Fusarium oxysporum f. sp. phaseoli (MIC= 125 μg mL-1). Other fraction obtained from the metabolic extract of P. citrinum (F3a3 fraction and citrinin), showed inibitory activity (100% inibition) to Leishmania infantum promastigotes. In the study of secondary metabolites of P. simplicissimum it was obtained F2b fraction, active against L. infantum (100% inhibition), which were isolated andrastin A and penicisoquinoline compounds, the first report of its production for this species, as well 5 unidentified compounds. In the study of secondary metabolites from A. melanogenum was isolated the methyl-orsellinate compound, first reported for this fungus. From the same strain was obtained F1d2l fraction, active against L. infantum (100% inhibition), from which were isolated 2 unidentified compounds. This is the first report of fungi isolated from Alcatrazes Island anthuriums and the study of their secondary metabolites. This study presents contribution to knowledge of endophytic fungi and their metabolic potential with applications in the medical and agronomic fields.
163

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.
164

ProteomicQTL (pQTL):Kopplungsanalyse zur Identifizierung genetischer Modulatoren des Plasmaproteoms

von Delft, Annette 02 May 2013 (has links) (PDF)
Ziel der vorliegenden Arbeit war die Identifizierung genetischer Faktoren, die das Plasmaproteom regulieren. Die Untersuchungen wurden im Modellsystem einer F2-Kreuzung zweier Inzucht-Mausstämme (FVB.LDLR-/-, C57BL/6.LDLR-/-) durchgeführt, die sich in ihrer Atheroskleroseausprägung unterscheiden. Von jedem der 453 Tiere der F2-Generation wurden Plasmaproteomprofile mittels Massenspektrometrie (MALDI-TOF) generiert. Diese Spektren wurden in zwei unabhängigen Datenanalysen ausgewertet und eine Kopplungsanalyse (QTL-Analyse, quantitative trait loci) der Phänotypen mit jeweils 192 genetischen Markern in jedem der F2-Tiere durchgeführt. So wurden die Datensätze von Proteom und Genom miteinander kombiniert, um Genorte, die mit unterschiedlich regulierten Proteinen in Verbindung stehen, zu identifizieren. Dieser Ansatz ist bisher in der Literatur nicht beschrieben worden. In der vorliegenden Arbeit wird sowohl die Methodik der statistischen Auswertung als auch die weitere Analyse der generierten Daten beschrieben. Es wurden zahlreiche hochsignifikante Kopplungssignale gefunden, von denen zwei durch die Identifizierung von Proteinen verifiziert werden konnten. Es handelt sich hierbei um das Apo-A2 des HDL auf Chromosom 1 und Hämoglobin subunit alpha auf Chromosom 11. Eine Kolokalisation der gefundenen Proteine mit Loci der Atherosklerosedisposition konnte nicht identifiziert werden. Dieser Ansatz zeigt erstmals, dass eine hypothesenfreie Verbindung proteomischer und genomischer Daten möglich ist und zur Identifizierung genetisch regulierter Plasmaproteine beitragen kann.
165

Identifizierung von Enterobacteriaceae und Nonfermentern mittels MALDI-TOF MS unter besonderer Berücksichtigung von multiresistenten und darmpathogenen Erregern

Knoop, Nicolas 05 January 2015 (has links) (PDF)
Der zeitnahe und möglichst sichere Nachweis bakterieller Krankheitserreger und deren Empfindlichkeit gegenüber verfügbaren antibakteriell wirksamen Chemotherapeutika (Antibiotika) stellt einen Hauptaufgabenbereich der medizinischen mikrobiologischen Routinediagnostik dar. Hierzu wurden im Laufe der Jahre unterschiedliche Methoden entwickelt, womit von der genauen Beschreibung der Kolonie- und mikroskopischen Morphologie, Anfärbbarkeit und Formation über die Charakterisierung der biochemischen Leistungsfähigkeit bis hin zur genauen Sequenzierung des gesamten Genoms ein enormer Fortschritt zu verzeichnen war. Seit Mitte der 1990er Jahre etablierte sich die Massenspektrometrie als phänotypisches Nachweisverfahren und gewann zunehmend an Bedeutung. Ebenso konnten Erfolge beim Nachweis Antibiotika resistenter Bakterien verzeichnet werden. Um das Potential dieser noch jungen Nachweismethode weiter zu erforschen, wurden in dieser Arbeit Spezies der Familie Enterobacteriaceae und der Nonfermenter in eine eigene massenspektrometrische Datenbank aufgenommen, um diese als Grundlage zur Validierung des Identifizierungspotentials der Methode mittels Blindstudie zu nutzen. Im selben Arbeitsschritt wurde der Versuch unternommen, Antibiotika resistente Stämme im Zuge der Speziesidentifizierung zu detektieren, um so Aussagen über eine mögliche Einschränkung der therapeutischen Möglichkeiten und gegebenenfalls notwendigen Hygienemaßnahmen treffen zu können.
166

Identification of proteins from the marine red macroalga Hypnea musciformis by proteomic analysis / Identificação de proteínas da macroalga marinha vermelha Hypnea musciformis por análise proteômica

Nascimento, Fernando Edson Pessoa do January 2014 (has links)
NASCIMENTO, Fernando Edson Pessoa do. Identificação de proteínas da macroalga marinha vermelha Hypnea musciformis por análise proteômica. 2014. 62 f. : Dissertação (mestrado) - Universidade Federal do Ceará, Centro de Ciências Agrárias, Departamento de Engenharia de Pesca, Fortaleza-CE, 2014 / Submitted by Nádja Goes (nmoraissoares@gmail.com) on 2016-07-14T13:19:27Z No. of bitstreams: 1 2014_dis_fepnascimento.pdf: 1476110 bytes, checksum: a37b0bfbc43de7460d0259fd1a190bb2 (MD5) / Approved for entry into archive by Nádja Goes (nmoraissoares@gmail.com) on 2016-07-14T13:19:45Z (GMT) No. of bitstreams: 1 2014_dis_fepnascimento.pdf: 1476110 bytes, checksum: a37b0bfbc43de7460d0259fd1a190bb2 (MD5) / Made available in DSpace on 2016-07-14T13:19:45Z (GMT). No. of bitstreams: 1 2014_dis_fepnascimento.pdf: 1476110 bytes, checksum: a37b0bfbc43de7460d0259fd1a190bb2 (MD5) Previous issue date: 2014 / Atualmente vivemos em uma acirrada competição na pesquisa de desenvolvimento de novos produtos biotecnológicos, o ambiente marinho pode ser visto como uma fonte de materiais biotecnológicos funcionais. Recentemente, estudos demostram que dentro do ambiente marinho as algas se destacam como organismos com grande potencial biotecnológico por possuirem em sua composição várias moléculas bioativas que apresentam diversas e intensas atividades biológicas. Dentre todos os grupos algais, neste trabalho enfatizamos o das algas vermelhas, a qual a espécie de estudo é a alga marinha vermelha Hypnea musciformis (Wulfen). J. V. Lamouroux pertence à ordem Gigartinales e a família Hypneaceae, abundante no litoral do Ceará. Trabalhos biotecnológicos e científicos são realizados com esta espécie, neste sentido o objetivo principal deste trabalho e identificar e caracterizar proteínas existente neste organismo através de uma abordagem proteômica, que é uma área recente na ciência, que permite bioprospectar um conjunto de proteínas presentes num organismo através do uso de ferramentas analíticas, pois, em condições fisiológicas específicas, o funcionamento do sistema biológico pode ser refletido por análise do proteoma do mesmo, e assim a sua expressão gênica funcional. Considerando a carência de estudos sobre proteômica em algas marinhas e em especial da carragenófita Hypnea musciformis, o presente trabalho tem como objetivo principal desenvolver metodologias de separação de proteínas de extrato protéico de Hypnea musciformis e identificar as proteínas expressas pelo organismo. Neste trabalho conseguimos estabelecer uma metodologia de separação de proteínas deste organismo a partir de um extrato fracionado com sulfato de amônio e através de espectrometria de massas, identificar algumas proteínas da alga marinha. Desta forma, sendo de fundamental importância para o enriquecimento na literatura de proteomica de macroalgas marinhas. Os resultados deste trabalho que estão de acordo com o nosso objetivo foi a identificação de 3 proteínas por técnica de espectrometria de massas utilizando ionização do tipo eletrospray da fração protéica 20-40% e a identificação de algumas proteínas através do Mascot / We currently live in a fierce competition in the research development of new biotechnology products, the marine environment can be seen as a source of functional biotechnological materials. Recent studies show that within the marine environment algae stand out as organisms with great biotechnological potential by having in its composition various bioactive molecules that have diverse and intense biological activities, among all algal groups in this study emphasize the of red algae, which the kind of study is red seaweed Hypnea musciformis (Wulfen). JV Lamouroux belongs to the order Gigartinales and Hypneaceae family, abundant on the coast of Ceará. Biotechnological and scientific works are carried out with this species, in this sense, the main objective of this work is to identify and characterize proteins existing in this organism through a proteomics approach, is a new area in science that allows bioprospect a set of proteins in an organism by using analytical tools because under specific physiological conditions the biological functioning of the system can be reflected by the proteome analysis of the same, and thus the functional gene expression. Considering the lack of studies on proteomics in seaweed and in particular the carragenófita Hypnea musciformis, this paper aims to develop methods for separating proteins from protein extract of Hypnea musciformis and identify the proteins expressed by the organism. In this work we have established a methodology for separating proteins of this organism from a fractionated extract with ammonium sulfate and by mass spectrometry to identify proteins of some kelp, thus being of fundamental importance for the enrichment of macroalgae in the proteomics literature marine. The results of this work are consistent with our objective was the identification of three proteins by mass spectrometry using electrospray ionization type protein fraction of 20-40% and the identification of some proteins by Mascot
167

Tanins condensés pour mousses rigides et nouvelles réactions de réticulations des matériaux polyphénoliques / Condensed tannins for rigid foams and novel cross-linking reactions of polyphenolic materials

Santiago-Medina, Francisco José 08 December 2017 (has links)
Une alternative aux produits industriels de type phénol ou résorcinol peut être des tanins ou de la lignine. Les deux sont des polyphénols naturels, le tanin est extrait de différentes parties de plantes, tandis que la lignine est habituellement obtenue comme sous-produit dans les industries papetières. Ces deux produits sont la base principale sur laquelle j’ai travaillé pendant le développement de cette thèse. Dans une première partie, une étude de caractérisation et de différenciation entre différents tannins ayant la même origine mais que présentent un comportement différent lorsqu'ils sont utilisés dans la même application dans les mêmes conditions a été effectuée. Cette étude met en évidence la GPC comme technique fondamentale pour la différenciation des tanins de quebracho sulfités. D'autre part, les interactions entre différentes substances avec du tanin et de la lignine ont été étudiées. Comme l’étude de la réaction entre les diamines (telles que l'hexaméthylènediamine) avec du tanin et de la lignine pour obtenir des résines polycondensées. En outre, dans cette section ont été obtenus des polyuréthanes avec au moins 70% de substances naturelles dans leur préparation sans utiliser d'isocyanate dans le procédé. De plus, des aldéhydes dérivés de la lignine, comme la vanilline, ont été utilisés avec le tanin de pin pour la fabrication d'adhésifs dans la préparation de panneaux de particulaires, obtenant des résultats satisfaisants selon les normes européennes et des substances complètement naturelles. Enfin, dans le cadre d'un projet industriel les étapes initiales pour le développement d'une mousse de tanin rigide applicable par projection pour l'isolation thermique des bâtiments ont été réalisées. Lorsqu'un nouveau système de moussage mécanique a été développé pour des mousses de tanin basées sur des mousses de lutte contre incendie à base de tanin ou dans les mousses des opérations d’ouverture du tunnel, ce nouveau système de moussage évite les problèmes de retrait lors de la formation de la mousse / An alternative to industrial phenol or resorcinol industrial products may be tannins or lignin. Both are natural polyphenols, the tannin is extracted from different parts of plants, while lignin is usually obtained as a secondary product in the pulp and paper mill. These two products are the main basis on which I have worked during the development of this thesis. In a first part, a study of characterization and differentiation between different tannins with the same origin and that present a different behavior when used in the same application under the same conditions has been done. Highlighting the GPC as a fundamental technique for the differentiation between sulphited quebracho tannins. On the other hand, the interactions between different substances with tannin and with lignin have been studied. As the study of the reaction between diamines (such as hexamethylenediamine) with tannin and lignin to obtain a polycondensed resins. Also, in this section have been obtained polyurethanes with at least 70% of natural substances in their preparation without using any isocyanate in the process. In addition, aldehydes derived from lignin, such as vanillin, have been used next to pine tannin for the manufacture of adhesives in the preparation of particleboards, obtaining satisfactory results according to European standards and from completely natural substances. Finally, within an industrial project the initial steps have been carried out for the development of a rigid tannin foam applicable by projection for the thermal insulation of buildings. Where a new mechanical foaming system has been developed for tannin foams based in fire-fighting foams or in the foams of the tunneling operations, this new system of foaming avoids the problems of shrinkage during the formation of the foam
168

Identification du repas sanguin des moustiques par MALDI-TOF MS / Identification of mosquito blood meal sources vector by MALDI‑TOF MS

Niare, Sirama 23 November 2017 (has links)
Le MALDI-TOF MS (Matrix Assisted, Laser Desorption/Ionization Time-Of-Flight Mass Spectrometry) est une technique protéomique qui est utilisée en routine pour l’identification des microorganismes dans les laboratoires de microbiologie. Ainsi, dans ce travail nous avons évalué le MALDI-TOF MS pour l’identification du repas sanguin des moustiques. Dans la première partie de notre travail, une revue bibliographique a été effectuée sur les différentes méthodes (sérologiques, biologie moléculaire) connues dans les études de préférence trophiques des arthropodes. La deuxième partie fut l’optimisation du MALDI-TOF MS pour l’identification de l’origine du repas sanguin des moustiques. Pour l’optimisation, Anopheles gambiae Giles et Aedes albopictus ont été artificiellement nourris sur le sang de plusieurs hôtes vertébrés en utilisant l’appareil Hemotek durant deux heures sous les conditions standard. Nos résultats ont montré que la comparaison des spectres provenant des moustiques nourris sur le même type de sang révèle une grande reproductibilité des profils protéiques. L’interrogation des MS spectres contre la base de données a révélé une identification correcte de l'origine du repas sanguin pour les spécimens collectés moins de 24 heures après la prise du repas sanguin. Pour les échantillons collectés sur le terrain, le MALDI-TOF MS a permis de détecter dans le repas de sang des moustiques une grande diversité d’hôtes domestiques. En conséquence la technique MALDI-TOF MS serait un outil efficace pour les études de surveillance épidémiologique des maladies vectorielles et l'identification de la préférence trophique de spécimens fraichement gorgés. / MALDI-TOF MS (Matrix Assisted, Laser Desorption/Ionization Time-Of-Flight Mass Spectrometry) is a proteomic technique that routinely used for microorganisms identification in clinical microbiology laboratory. Recently, the MALDI-TOF MS was successfully used as a innovative tool for arthropod identification. Thus, in this work we evaluated the MALDI-TOF MS to identify the blood meal sources from engorged mosquitoes. In the first part of our work, a bibliographical review was carried out on the different methods (serological, molecular biology) known in the trophic preference determination of hematophagous arthropods. The second part was optimization of the MALDI-TOF MS for identifying the origin of the blood meal of mosquitoes. For optimization, the Anopheles gambiae Giles and Aedes albopictus were artificially fed on several vertebrate hosts blood using the Hemotek device for two hours under standard conditions. Our results showed intra-species reproducibility and inter-species specificity of MS spectra from mosquitoes engorged on the same or different vertebrate hosts. The MS spectra querying against the database reveal a correct identification of the the blood meal origin from the specimens collected less than 24 hours post-feeding. For field samples, MALDI-TOF MS allowed to detect the mosquitoes blood meal fed on wide variety of domestic hosts. Consequently the MALDI-TOF MS technique would be an effective tool for epidemiological surveys of vector-borne diseases and the identification of the trophic preference of mosquito freshly engorged.
169

Exploration du microbiote digestif : stratégies de culture des bactéries anaérobies et de culture difficile / Study of anaerobes and fastidious bacteria of the human gut microbiota

Dione, Niokhor 23 November 2017 (has links)
Le microbiote digestif, composé de 1012 à 1014 bactéries par gramme de selle, est dominé par les bactéries anaérobies. Ces dernières, qui dépassent largement les aérobies, ont été découvertes en 1865 par Louis Pasteur dans ses travaux sur la fermentation. Les bactéries anaérobies représentent un intérêt médical particulier par leur implication dans les maladies infectieuses et métaboliques. Les anaérobies sont caractérisés par leur difficulté à être cultivés, car nécessitant une absence ou des concentrations faibles d’oxygène. Ainsi les connaissances sur ces microorganismes étaient limitées. Cependant, avec l’avènement des outils de biologie moléculaire notamment le séquençage à haut débit et le concept culturomics associé à l’identification par spectrométrie de mass MALDI-TOF, la connaissance des microorganismes anaérobies a été accentuée. Dans ce travail, nous nous sommes attelés dans un premier temps à la mise au point d’un milieu de culture efficace pour la culture des bactéries anaérobies et les tests d’activités antimicrobiennes. Nous avons montré dans un deuxième temps que culturomics, associé au MALDI-TOF, était un outil puissant dans l’identification des bactéries anaérobies en microbiologie clinique, mais également dans l’exploration de la diversité microbienne du tube digestif. Cette technique nous a permis d’isoler 19 nouvelles espèces de bactéries anaérobies dont 9 ont été décrites dans la troisième partie de ce travail. / The human gut microbiota is known to contain around 1012 to 1014 bacteria per gram of feces, with the majority being anaerobic. The latters were first discovered in 1865 by Louis Pasteur while working on fermentation. Anaerobic bacteria are known to play an important role in health and diseases and thus have taken a lot of attention in the medical field, especially in infectiousdiseases and metabolism. These bacteria are known for its sophisticated culture system because its growth requires little to no oxygen. Nevertheless, few is known about these type of microorganisms but with the advancement of molecular biology and sequencing techniques, its study became wider. Culturomics, is a recently developed culture-based approach that relies on optimizing culture conditions for bacterial growth and its identification by MALDI-TOF MS and 16S rRNA sequencing. The present work aims to create and optimized culture condition for anaerobic bacteria along with testing its anaerobic activities. Also, we aim to demonstrate the efficiency of Culturomics and MALDI-TOF in culturing, identifying and describing anaerobic bacteria in clinical microbiology and in the human gut. This approach allowed us to isolate 19 new anaerobic species out of which 9 has been described in this work.Keywords: Human gut microbiota, culture of anaerobic bacteria, culturomics, MALDI-TOF.
170

Análise do secretoma de isolados do fungo Trichoderma asperellum (TR356) em resposta ao fungo fitopatogênico Sclerotinia sclerotiorum / Analysis of Trichoderma asperellum (TR356) secretome in response to plant pathogenic fungus Sclerotinia sclerotiorum

Rodrigues, Amanda Rafaela 23 October 2014 (has links)
Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2015-11-19T10:15:55Z No. of bitstreams: 2 Dissertação - Amanda Rafaela Rodrigues - 2014.pdf: 1648839 bytes, checksum: 9a00f301e577d05e94214afe813688c5 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2015-11-19T10:17:31Z (GMT) No. of bitstreams: 2 Dissertação - Amanda Rafaela Rodrigues - 2014.pdf: 1648839 bytes, checksum: 9a00f301e577d05e94214afe813688c5 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2015-11-19T10:17:31Z (GMT). No. of bitstreams: 2 Dissertação - Amanda Rafaela Rodrigues - 2014.pdf: 1648839 bytes, checksum: 9a00f301e577d05e94214afe813688c5 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2014-10-23 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The genus Trichoderma is represented by non-pathogenic soil fungi that have been studied by act as biological control agents against fungal pathogens, such as Sclerotinia sclerotiorum, the fungus that causes white mold, besides that, reduce environment and human health risks by being able to replace agrochemicals. Proteomic strategies with MS techniques have been important tools in studies of patterns identification for protein expression in different growth conditions. This work aims to development new strategies that enable the detection and identification of proteins secreted by Trichoderma asperellum (TR356) and Sclerotinia sclerotiorum when inoculated together and separated. The results obtained by MALDI / TOF analysis allowed the identification of a β-1.3--glucanosiltransferase and α-1.2-Dmannosidase, demonstrating the possibility of proteins identification for better comprehension about interaction between these organisms. It was therefore possible to identify the proteins through strategies used, but further analysis are required in order to elucidate the function and interaction of proteins secreted by the fungus Trichoderma asperellum TR356 against S. sclerotiorum. / OgêneroTrichodermaérepresentadoporfungosdesolonãopatogênicosquesãoestudad osporsuaaçãocomoagentesdecontrolebiológicocontrafungosfitopatógenos,comoScler otiniasclerotiorum,ofungocausadordomofobranco.Osfungos Trichoderma spp.atuamcomoimportantesagentesdecontrolebiológico,diminuindoosriscosàsaúdehu manaeaomeioambienteporseremcapazesdesubstituirosagroquímicos.Estratégiasprot eômicas juntamente com técnicas de MSsãoimportantesferramentasemestudosdepadrão, identificação e expressãodeproteínasemdiferentescondiçõesdecrescimento.Levando em consideração a importância de tais estudos, o presente trabalho tem por objetivo o desenvolvimento de novas estratégias que possibilitem a detecção e identificação de proteínas secretadas por Trichoderma asperellum (TR356) e Sclerotinia sclerotiorum quando inoculados juntos e/ou separados os dois organismos vivos. Os resultados obtidos através das análises por MALDI/TOF permitiram a identificação dasproteínas, β-1,3-glucanosiltransferase e α-1,2-D-mannosidase,demonstrando a possibilidade de identificaçãopara o entendimento futuro acerca da interação destes organismos. Foi possível, portanto, a identificação das proteínas através das estratégias utilizadas, porém serão necessárias futuras análises afim de elucidar a interação e função das proteínas secretadas através do fungo T. asperellum TR356sobre S. sclerotiorum.

Page generated in 0.0198 seconds