Resumo: Algumas avaliações da capacidade de fecundação como a produção in vitro de embriões (PIV) e a coloração vital indicam que a sexagem de espermatozóides por centrifugação em gradiente de densidade pode causar diminuição nas taxas de desenvolvimento embrionário, entretanto, não são conclusivas quanto à avaliação da integridade das membranas espermáticas. Com o intuito de obter dados mais precisos em relação à viabilidade espermática pós-sexagem, foram descongeladas doses de sêmen de 6 touros diferentes, e avaliadas quanto aos danos espermáticos causados pela centrifugação em gradiente descontínuo de Percoll (com densidade variando de 1,111g/mL a 1,123g/mL). Antes e após a centrifugação dos espermatozóides, além das avaliações de concentração, motilidade e morfologia, o sêmen foi ainda avaliado quanto à integridade das membranas plasmáticas, acrossomal e mitocondrial pela associação das sondas fluorescentes: Iodeto de Propídio (PI), aglutinina de Pisum Sativum conjugado a Isotiocianato de flurosceína (FITC-PSA) e Iodeto de 5,5',6,6'-tetracloro- 1,1,3,3'-tetraetilbenzimidazolilcarbocianina (JC-1). Os resultados demonstraram que o processo de separação de espermatozóides X e Y por centrifugação em gradiente de densidade promoveu uma melhora nas características associadas à motilidade progressiva, além de uma significativa diminuição na incidência de defeitos maiores. Ainda nas amostras pós-centrifugação, foi observado um aumento no percentual de células com Membrana Plasmática Intacta e com Alto Potencial Mitocondrial. No entanto, o percentual de células com Membrana Acrossomal Intacta foi sensivelmente diminuída provavelmente devido ao fenômeno de reação acrossomal desencadeado pela centrifugação. / Abstract: Some fecundity evaluations as the in vitro embryo production (IVP) and the vital stains have indicating that the density gradients centrifugation techniques can reduce the embryo development rates. However they are not conclusive for the integrity of spermatic membranes. Wit the purpose of obtain more precise sperm viability data after the sexing procedure, frozen semen samples from six different bulls were thawed and assessed for spermatic damage caused by centrifugation in discontinuous Percoll gradient (with density varying from 1,111g/mL to 1,123g/mL). Before and after the separation of X-bearing bovine sperm, were evaluated the sperm concentration, motility and morphology. Moreover the semen samples were assessed for integrity of plasma, acrosome and mitochondrial membranes by fluorescent probes association: propidium iodide (PI), fluorescein isothiocyanate-Pisum sativum agglutinin (FITC-PSA) and 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolcarbocyanine iodide (JC-1). The results demonstrated that the X-bearing sperm separation process by density gradient centrifugation caused an increase in the progressive motility parameters and a decrease in the major defects incidence. In addition, it was observed an increase in the cells categories with Intact Plasma Membrane and High Mitochondrial Membrane potential in the post-centrifugation samples. Nevertheless, the percentage of cells with Intact Acrossome Membrane was reduced probably due to the acrosome reaction phenomenon induced by centrifugation. / Orientadora: Vera Fernanda Martins Hossepian de Lima / Coorientador: Rubens Paes de Arruda / Banca: Gisele Zoccal Mingoti / Banca: Eneiva Carla Carvalho Celeghini / Mestre

O trabalho tem como objetivo determinar a influencia da concentração de monoestearato de sorbitano, componente do núcleo oleoso das nanocápsulas, na cinética de liberação do éster etílico de indometacina a partir de nanocápsulas de poli(ε-caprolactona) (PCL). Com este propósito o éster etílico de indometacina foi associado a cada sistema e sua hidrólise alcalina foi realizada para simular uma condição sink. A velocidade de consumo do éster etílico de indometacina foi menor conforme o aumento da concentração do monoestearato de sorbitano. O tempo de meia-vida do consumo do éster etílico de indometacina associado as nanocápsulas foi relacionado com a concentração do monoestearato de sorbitano, sendo maior, enquanto maior a concentração do monoestearato. O mecanismo de liberação foi determinado como sendo transporte anômalo. Foi observada uma relação linear direta entre o aumento da concentração do monoestearato de sorbitano e a concentração de partículas nas suspensões de nanocápsulas (R2=0,9711). Mistura de outras nanopartículas que não as nanocápsulas, foram observadas e caracterizadas. O fluxo difusional do éster a partir das nanocápsulas foi determinado e diminuiu significativamente com o aumento da concentração do monoestearato, devido a mudanças na viscosidade do núcleo das nanocápsulas com o aumento da concentração do monoestearato de sorbitano. Por fim, os resultados demonstraram que o principal fator que contribui para o retardo no tempo para o consumo do éster etílico de indometacina é a relação direta entre a concentração do monoestearato de sorbitano e a permeabilidade das nanocápsulas (R=0,9894). / The aim of this work was to evaluate the influence of the sorbitan monoestearate concentration, one of the components of the oil core of the nanocapsules, in the release kinetic of the indomethacin ethyl ester-loaded poli(ε-caprolactone) nanocapsules. In this way, the indomethacin ethyl ester was entrapped within each system and its alkaline hydrolysis was carried out to simulate a sink condition. The rate for the indomethacin ethyl ester consumption decreased with the increase in sorbitan monostearate concentrations. The indomethacin ethyl ester half-live was related to the sorbitan monostearate concentration, increasing as the sorbitan monostearate concentration increased. The drug release mechanism was determined as anomalous transport. Linear correlations were obtained between the increase in the sorbitan monostearate concentration and the particles concentration in the suspensions (R2 = 0.9711). Mixture of different nanoparticles that are not nanocapsules were observed by density gradient and characterized. The indomethacin ethyl ester fluxes from the nanocapsules were determined and presented a decrease of the flux as the sorbitan monostearate concentration increased. This result was related to changes in the oil core viscosity caused by the variation of the sorbitan monostearate concentration. Finally, the results demonstrated that the main factor that contributes for the delaying in the time for the indometahcin ethyl ester consumption was the direct relation between the sorbitan monostearate concentration and the apparent permeability of the nanocapsules (R2 = 0.9894).

Conselho Nacional de Desenvolvimento Científico e Tecnológico / Preimplantation genetic diagnosis (PGD) is becoming a current issue in animal reproduction biotechnology due to economical reasons. Predetermining the sex of offspring is one example of PGD. This study aimed to determine the percentage of male and female bovine embryos in vitro produced after oocyte fertilization with Percoll density gradient centrifugation or with self-migration (swim-up) selected semen. In experiment 1, sperm selection was performed by 90%-45% discontinuous Percoll density gradient centrifugation (T1) and swim-up (T2). In experiment 2, along side the discontinuous gradient, a 67.5% continuous density gradient, and centrifugation time of 5 and 10 minutes were used. A total of 4 treatment groups was defined (TI = continuous, 5 minutes, TII = discontinuous, 5 minutes, TIII = continuous, 10 minutes and TIV = discontinuous, 10 minutes). Polymerase chain reaction (PCR) was used to determine the sex of the embryos. T1 (n=185) resulted in 48.65% (n=90) male embryos and 51.35% (n=95) female embryos and T2 (n=142) in 58.45% (n=83) male and 41.55% (n=59) female embryos. In experiment 2, the percentages of male and female embryos obtained in TI (n=93), TII (n=70), TIII (n=82) and TIV (n=82) were 49.46% (n=46) and 50.54% (n=47), 57.14% (n=40) and 42.86% (n=30), 36.59% (n=30) and 63.41% (n=52) and 48.78% (n=40) and 51.22% (n=42), respectively. There was no difference on the percentage of males and females in all treatment groups from experiments 1 and 2 when these were individually compared to the expected percentage of 50% of each sex. There was also no difference in male and female embryo percentage between treatment groups in experiments 1 and 2. / O diagnóstico genético pré-implantação (DGP) vem se destacando na área da biotecnologia da reprodução animal por motivos econômicos. Um exemplo de DGP é a predeterminação do sexo da prole. Neste estudo foi verificada a percentagem de embriões bovinos machos e fêmeas produzidos in vitro após a fertilização de oócitos com sêmen selecionado por centrifugação em gradiente de densidade de Percoll ou por migração ascendente (swim-up). No experimento 1 a seleção espermática foi realizada usando o gradiente descontínuo de Percoll de 90% e 45% (T1) e o swimup (T2). No experimento 2 foi utilizado, além do gradiente descontínuo, um gradiente contínuo de densidade de Percoll de 67,5%, e tempos de centrifugação de 5 e 10 minutos, totalizando 4 tratamentos (TI = contínuo 5 minutos, TII = descontínuo 5 minutos, TIII = contínuo 10 minutos e TIV = descontínuo 10 minutos). A sexagem dos embriões foi realizada através da técnica da reação em cadeia da polimerase (PCR). No T1 (n=185) foram obtidos 48,65% (n=90) de embriões masculinos e 51,35% (n=95) de femininos e no T2 (n=142) 58,45% (n=83) foram machos e 41,55% (n=59) fêmeas. No experimento 2, a percentagem de embriões masculinos e femininos no TI (n=93), TII (n=70), TIII (n=82) e TIV (n=82) foi de 49,46% (n=46) e 50,54% (n=47), 57,14% (n=40) e 42,86% (n=30), 36,59% (n=30) e 63,41% (n=52), e 48,78% (n=40) e 51,22% (n=42), respectivamente. Não houve alteração na percentagem de machos e fêmeas nos tratamentos dos experimentos 1 e 2 quando estes tratamentos foram comparados individualmente com a percentagem teoricamente esperada de 50% de cada sexo. Também não houve alteração na percentagem de machos e fêmeas na comparação entre os dois tratamentos do experimento 1 e entre os quatro tratamentos do experimento 2.

Les interactions non-covalentes ont une importance fondamental pour la chimique. Les interactions entre un catalyseur et le substrat, interactions entre matériaux, synthèse des enantiomers parmi autres réactions chimiques sont décrivent par interactions non-covalentes. Elles sont fondamental pour designer nouveaux matériaux. Les interactions non-covalents sont très suivant visualisées à partir de mesures de contactes atomiques qui utilisent des donnes de rayon de van de Waals. Cette type d'approximations ne sont pas très flexible pour comprendre l'interaction avec l'environnement. Aujourd'hui les approximations qui utilisent des fonctions dans l'espace réel (i.e. la densité électronique) sont très utilisent pour visualiser les interactions non-covalentes. Dans cet thèse, on analyse la méthode NCI pour visualiser interactions chimiques. On analyse les gradient réduit de la densité, ingrédient fondamental dans la méthode NCI. On montré que cette fonction est liée au la densité d'énergie cinétique et au comportement bosonique du système. On montre que la méthode NCI peut être utilisée pour analyser tous les types d'interactions; dès interactions covalentes aux non-covalentes. Finalement la méthode est appliqué à la réactivité chimique. / Non-covalent interactions are of paramount importance in chemistry. Interactions between a catalyst and its substrate, self-assembly of nanomaterials, enantiomer production and many other chemical reactions, are most of the time non-covalent in nature. They are also fundamental for crystallographic analysis, since they set up the scenario for molecular crystallization, whose guiding rules are still a fruitful filed of research. Non-covalent interactions are frequently visualized using distance dependent contacts, generally without consideration of hydrogen atoms. Most of these interactions are usually identified by the use of tabulated van der Waals radii, which are not flexible enough to reveal the interplay with the environment. New approaches, based on 3D functions that can be derived either form experiment or computation (e.g. the electro density) are now widely used to identify and visualize non-covalent interactions. In this thesis we analyse the NCI method, and namely, its main ingredient, the reduced density gradient. Its capabilities for visualizing chemical interactions are examined. This 3D function is then, connected with the kinetic energy density and a interpretation of the reduced density gradient in terms of the bosonic behaviour of the electronic system is presented. Then, the NCI method is applied to visualise and analyse chemical interactions: from covalent to non-covalent interactions. The chemical reactivity is also addressed. The NCI method is applied to rationalised the outcome of several reactions.

The presence of pathogens in semen can compromise the outcome of assisted reproductive treatment, together with the possibility of the female partner or offspring becoming infected. This is cause for concern, especially in South Africa with a high prevalence of HIV-1. Most of these infected individuals are in their reproductive years with the desire to have their own genetically related children. Therefore, assisted reproductive treatment with effective risk reduction procedures, such as semen processing for the elimination of these pathogens is crucial. However, during sperm preparation by standard discontinuous density gradient centrifugation, the supernatant is aspirated to allow access to the purified sperm pellet. Pathogens from the upper layers can adhere to the inside surface of the test tube and flow down to re-infect the purified sperm sample. The use of a centrifuge tube insert may prevent the re-contamination of sperm samples after discontinuous density gradient centrifugation. Furthermore, seminal pathogens can bind specifically or non-specifically to spermatozoa, rendering semen decontamination procedures ineffective. Serine proteases, such as trypsin, have been demonstrated to effectively inactivate viruses and to break pathogen-sperm bonds. However, the addition of a protease to density gradient layers during semen processing could have a negative impact on sperm parameters. This research was therefore aimed towards the determination of: i) The effect of semen processing with trypsin and trypsin inhibitor on sperm parameters. ii) The prevalence of various bacteria in semen samples from men attending the Reproductive and Endocrine Unit at Steve Biko Academic Hospital. iii) The effectiveness of semen processing by discontinuous density gradient centrifugation with a centrifuge tube insert, for the elimination of some of the most prevalent bacteria, white blood cells and in vivo derived HIV-1. Evaluation of sperm parameters after semen processing indicated that trypsin and trypsin inhibitor did not have an impact on sperm mitochondrial membrane potential, vitality, motility and zona binding potential, or acrosin activity, respectively. Seminal bacteria were highly prevalent in patients wishing to participate in the Unit’s assisted reproductive program, with 49.5% of semen samples presenting with positive bacterial cultures. Semen processing by means of discontinuous density gradient centrifugation with the tube insert, eliminated significantly more in vitro derived (spiked) bacteria and white blood cells from semen compared to processing without the insert. Furthermore, the semen decontamination procedure was effective in removing HIV-1 RNA from 100% of samples and proviral DNA from 98.1% of semen samples from HIV-1 sero-positive patients. The effectiveness of discontinuous density gradient centrifugation for the elimination of seminal pathogens could, therefore, be improved by the addition of trypsin to the upper density layer, without supplementing the bottom layer with trypsin inhibitor. Additionally, semen decontamination efficiency could also be improved by the prevention of re-contamination of processed sperm samples by the utilization of a tube insert during discontinuous density gradient centrifugation. / Thesis (PhD)--University of Pretoria, 2014. / gm2014 / Obstetrics and Gynaecology / unrestricted

Hedgehog (Hh) proteins control animal development and tissue homeostasis. They activate gene expression by regulating processing, stability, and activation of Gli/Cubitus interruptus (Ci) transcription factors. Hh proteins are secreted and spread through tissue, despite becoming covalently linked to sterol during processing. Multiple mechanisms have been proposed to release Hh proteins in distinct forms; in Drosophila, lipoproteins facilitate long-range Hh mobilization but also contain lipids that repress the pathway. Here, we show that mammalian lipoproteins have conserved roles in Sonic Hedgehog (Shh) release and pathway repression. We demonstrate that lipoprotein-associated forms of Hh and Shh specifically block lipoprotein-mediated pathway inhibition. We also identify a second conserved release form that is not sterol-modified and can be released independently of lipoproteins (Hh-N*/Shh-N*). Lipoprotein-associated Hh/Shh and Hh-N*/Shh-N* have complementary and synergistic functions. In Drosophila wing imaginal discs, lipoprotein-associated Hh increases the amount of full-length Ci, but is insufficient for target gene activation. However, small amounts of non-sterol-modified Hh synergize with lipoprotein-associated Hh to fully activate the pathway and allow target gene expression. The existence of Hh secretion forms with distinct signaling activities suggests a novel mechanism for generating a diversity of Hh responses.

La structure spécifique des nanotubes rend ce matériau très intéressant dans l’élaboration de nanohybrides. La cavité interne des nanotubes permet l’encapsulation de molécule laissant la paroi externe libre pour une fonctionnalisation. Les nanotubes de carbone sont déjà bien connus pour l’élaboration de nanosondes Raman. Les molécules de colorants encapsulé dans leurs cavité interne sont protégées de l’irradiation du laser. Les propriétés électroniques de cette structure en carbone permettent le transfert d’énergie entre le colorant et le nanotube engendrant ainsi une extinction de la fluorescence du colorant. La surface du nanotube de carbone est libre pour réaliser des fonctionnalisations permettant de modifier certaines propriétés de la nanosonde. L’élaboration de nanohybride à partir de cette structure permet les analyses de « multiplexage » en changeant simplement le colorant encapsulé dans la cavité interne du nanotube et la fonctionnalisation en surface. La structure des nanotubes de nitrure de bore (BNNTs) est très similaire à celle de leurs homologues en carbone. La cavité interne permet également l’encapsulation de colorant cependant les propriétés électroniques résultantes de cette structure ne permet pas le transfert d’énergie. Les molécules de colorant encapsulé dans les BNNTs conservent donc leurs fluorescences. Des études précédentes démontrent qu’après encapsulation, le spectre de fluorescence du colorant α-sexithiophène (6T) est élargi et décalé vers les longueurs d’ondes plus grandes, c.-à-d. vers le rouge. L’hypothèse la plus probable, quant à la raison de ce phénomène, est que la grande distribution de taille de diamètre de l’échantillon de BNNTs permet différentes agglomérations de 6T. Les nanosondes résultantes sont composées d’un mélange d’agglomération de colorant absorbant à différentes longueurs d’onde. Afin de confirmer cette hypothèse, nous allons procéder au triage en taille de diamètre des BNNTs. Pour cela, plusieurs étapes sont nécessaires, comme la fonctionnalisation de la surface des BNNTs pour les rendre dispersible dans l’eau, l’encapsulation du colorant de 6T selon un protocole déjà connus dans la littérature et enfin le test d’une méthode de triage de nanotubes en fonction de leurs diamètres et donc de leurs densités. La méthode de triage sélectionnée parmi les méthodes découvertes dans la littérature, a démontré son efficacité sur les nanotubes de carbone mais n’a cependant jamais été testée sur les BNNTs. Ce mémoire présente les premiers résultats d’une séparation de nanosondes fluorescentes en fonction de leurs tailles de diamètre. / The specific structure of nanotubes is interesting for the synthesis of nanohybrides. Molecules are encapsulated in the internal cavity of the tube while the external wall remain free for further manipulation. Carbon nanotubes are already known for synthesizing Raman nanoprobes. Dyes encapsulated inside the nanotube are protected from irradiation. The electronic properties of the carbon structure lead to energy transfer between the dyes and the nanotubes, this result by the the extinction of the dye’s fluorescence. The carbon nanotube’s surface is free for functionalisation that can add some properties to the nanoprobe. The preparation process of nanohybrides with that structures permit some analyse in « multiplexing » by easily change the dye encapsulated or the functionalisation on the surface of the nanotube. The structure of boron nitride nanotubes (BNNTs) is similar to the carbon one. The internal cavity can encapsulate dyes but the electronic properties don’t permit the energy exchange. Encapsulated dyes inside BNNTs emit some fluorescence. Previous studies show some changes in the fluorescence spectrum of α-sexithiophene (6T) after encapsulation inside BNNTs. The spectrum shows larger bands and a red shift. This caracteristic can come from a large distribution of diameter sizes in the BNNT sample. Différent diameter sizes of nanotubes results in different agglomeration of dyes inside their internal cavities, and these differents nanoprobes are absorbing at different wavelengths. To confirm this hypothesis, we will separate BNNTs into their diameter sizes. Before that some manipulation is necesary, like the functionnalisation of the nanotubes’ surfaces for a better dispersion in water, the encapsulation of 6T realized with the process already known and the experience of a new method to separate nanotubes by size. This separating method is chose from all the method of separating carbon nanotubes but has never been tested on BNNTs. This document shows the first results of separating fluorescents nanoprobes by diameter size.

Mitochondriopathien sind Multisystemerkrankungen die durch verschiedene Defekte in den Energie (ATP) produzierenden Stoffwechselwegen der Mitochondrien verursacht sind. Will man Mitochondriopathien auf molekularer Ebene diagnostizieren, stößt man auf folgende Schwierigkeiten: (A) Ungefähr 1000 Gene sind an der Biogenese des Mitochondriums beteiligt. Die Dysfunktion jedes einzelnen dieser Gene kann potentiell zur Mitochondriopathie führen. (B) Mitochondriale Proteine werden durch zwei Genome, durch die mitochondriale und durch die nukleäre DNA kodiert. (C) Die klinischen Symptome der Patienten weisen selten auf die molekulare Diagnose, da der Phänotyp oft nur auf einem sekundären Energiemangel beruht. In der Regel besteht keine sichere Genotyp-Phänotyp-Relation. Mit den gegenwärtig zur Verfügung stehenden Methoden lassen sich bei nur 20% der Patienten Mutationen finden. Wir wollten daher eine neue Screening-Methode entwickeln, mit deren Hilfe wir hoffen, die Aufspürungsrate für mitochondriale Mutationen zu erhöhen. Die Gesamtheit der Proteine einer Organelle oder einer ganzen Zelle (ihr "Proteom") stellt das Verbindungsglied zwischen Geno- und Phänotyp dar. Aus diesem Grunde wollten wir das mitochondriale Proteom von gesunden Kontrollpersonen und von Patienten mit Mitochondriopathien untersuchen. Protein-Muster, die zwischen diesen beiden Gruppen abweichen, könnten die Aufmerksamkeit auf Gene und Proteine richten, die an der Entstehung des Krankheits-Phänotyps beteiligt sind. Um solch eine vergleichende Studie durchzuführen, muß zunächst eine Referenzkarte des normalen mitochondrialen Proteoms erstellt werden. In meinem Dissertationsprojekt habe ich diese grundlegende Arbeit durchgeführt und zahlreiche Proteine auf der Proteomkarte menschlicher Mitochondrien identifiziert, die aus Epstein-Barr-Virus-transformierten lymphoblastoiden Zellen gewonnen worden waren. Ich wählte diese Zellsorte als Untersuchungsmaterial, da sie nicht nur einfach von Patienten gewonnen werden, sondern auch potentiell permanent wachsen kann. Dies erlaubt die Züchtung einer hohen Zellzahl ohne übermäßigen Aufwand. Ich optimierte ein Protokoll zur Zentrifugation in einem hybriden Gradienten, mit dem genug gereinigte Mitochondrien aus 108 Zellen gewonnen werden konnten. Für die Referenzkarte benutzte ich die lymphoblastoide Zellline einer gesunden Kontrollperson. Die Methode der Wahl zur Proteinidentifikation in Proteom-Projekten ist die zweidimensionale Proteinelektrophorese gekoppelt mit der MALDI-TOF-Massenspektrometrie. Ich entdeckte mehr als 400 Punkte in meinem silbergefärbten zweidimensionalen Gel und analysierte die 141 stärksten Punkte nach in-gel Trypsin-Verdau und anschließender MALDI-TOF-Massenspektrometrie in einem Verfahren, das als "Peptide Mass Fingerprinting" (Peptidmassen-Fingerabdruck) bezeichnet wird. Mit Hilfe entsprechender Datenbanken konnte ich schließlich 115 verschiedene Proteinpunkte (entsprechen 95 verschiedenen Proteinen) identifizieren. 90 dieser Punkte (entsprechend 74 verschiedenen Proteinen) waren sicher mitochondrialer Herkunft und sind Komponenten aller wesentlichen im Mitochondrium lokalisierten Stoffwechselwege. 16 der 74 identifizierten mitochondrialen Proteine gehören zur Atmungskette. Obwohl 18 mitochondriale Proteine in der Datenbank SWISS-PROT als "Membran-assoziiert" annotiert sind, identifizierte ich nur vier Proteine mit sicheren Transmembrandomänen. Ich entdeckte keine der 13 durch die mitochondriale DNA kodierten Proteine, die alle stark hydrophobe Membranproteine sind. Andere Forscher sind bei dem Versuch diese Proteine zu identifizieren, auf die gleichen Schwierigkeiten gestoßen. Mit meiner Dissertationsarbeit habe ich unsere eigene Datenbank und Referenzkarte des mitochondrialen Proteoms lyphoblastoider Zellen erstellt. Diese Daten ermöglichen nun die Analyse des mitochondrialen Proteoms von Patienten. Meine weiteren Untersuchungen auf diesem Gebiet werden sich nun auf die genetische Variabilität des Proteoms gesunder Kontrollpersonen und auf das Proteom der Patienten mit Mitochondriopathien beziehen. / Mitochondrial disorders are multisystem diseases that can be caused by any defect in the energy (ATP) generating pathways in the mitochondria. The difficulty in diagnosing mitochondrial diseases on the molecular level arises from several obstacles: (A) About 1000 genes are involved in the biogenesis of mitochondria. The dysfunction of each of them may potentially cause mitochondriopathy. (B) The mitochondrial proteins are encoded by two genomes: the mitochondrial DNA and the nuclear DNA. (C) The clinical symptoms of the patients rarely suggest a molecular diagnosis since in most cases, the phenotype is a secondary phenomenon to energy depletion. Generally there is no genotype-phenotype relation. Based on current diagnostic methods in only 20% of the patients a mutation can be found. We therefore wanted to develop a new screening method by which we hope to increase the identification rate. Since the numerous proteins of an organelle or of a whole cell (its "proteome") connect the genotype with the phenotype, we set out to study the proteome of the mitochondrion in healthy individuals and in patients with mitochondrial diseases. Deviating protein patterns between the two individuals could direct the attention to disease-specific proteins and genes, which might be involved in the expression of a disease-phenotype. In order to perform such a comparison I first had to establish a normal reference map. In my dissertation project I performed this basic task and identified numerous mitochondrial proteins on the proteome-map of human mitochondria, which had been extracted from lymphoblastoid cells. I selected Epstein-Barr-Virus-transformed lymphoblastoid cells as samples not only because they are easily obtained from patients, but also due to their potential permanent growth. This approach allows the cultivation of high cell numbers without excessive expenditure of work and cost. I optimized a protocol for hybrid gradient centrifugation, by which enough mitochondria can be purified from 108 cells. I used a cultured lymphoblastoid cell line from a normal control patient and isolated mitochondria from it by using hybrid gradient centrifugation. In proteomics the combination of the high-resolution two-dimensional electrophoresis and matrix assisted laser desorption/ionization-time-of-flight-mass spectrometry (MALDI-TOF-MS) is currently the method of choice for protein identification. I detected more than 400 spots in a silver-stained two-dimensional gel. I analyzed the 141 strongest spots of it by trypsin in gel digestion and subsequent MALDI-TOF mass spectrometry in a process termed "peptide mass fingerprinting". After database search, I finally identified 115 protein spots (corresponding to 95 different proteins), 90 of which (corresponding to 74 different proteins) are of confirmed mitochondrial origin. These identified proteins are components of the main biological pathways located in the mitochondrion. 16 of the 74 identified mitochondrial proteins belong to the respiratory chain. Despite the fact that 18 mitochondrial proteins are annotated in the SWISS-PROT-database as "membrane associated proteins", only four of them have clear transmembrane domains. None of the proteins encoded by the mitochondrial DNA could be detected. All of them are hydrophobic membrane proteins. A similar difficulty in resolving these proteins was encountered by other research groups. With my dissertation I established our own database and reference map of the mitochondrial proteome of lymphoblastoid cells. These data will facilitate the analysis of the mitochondrial proteome in patients. My future research based on this dissertation will mainly focus on the genetic variation of the proteome of healthy individuals and on patients with mitochondrial diseases.

Ce travail de thèse a pour objectif l’élaboration et la caractérisation de composites Alumine/Zircone obtenus par voies conventionnelles, et dédiés à un usage orthopédique. Ces composites présentent une biocompatibilité prouvée, d’excellentes propriétés mécaniques ainsi qu’une grande stabilité. Ils sont plus résistants, plus fiables que l’alumine ou la zircone seules et permettent d’envisager des composants de tailles et formes plus exigeantes mécaniquement. Actuellement ces composites semblent les plus adaptés pour la réalisation de prothèses orthopédiques mais peuvent encore être optimisés via la modification des microstructures. La première partie de ce travail a concerné l’étude de la réalisation industrielle de composants de grande taille à partir d’une poudre. Les différentes étapes de l’élaboration sont traitées : pressage des composants, frittage et usinage. Cette première partie est majoritairement consacrée à l’étude des gradients thermique dans une sphère lors du frittage. Nous montrons qu’il est possible de modéliser et de mesurer les gradients thermiques dans le matériau de manière très réaliste, ainsi que d’obtenir des ordres de grandeur des contraintes mécaniques. On pourra ainsi envisager de tester numériquement les cycles de frittage en fonction de la géométrie des pièces frittées. Nous étudions par ailleurs la possibilité de réaliser un usinage des composants après un traitement de préfrittage, qui permettrait de diminuer les coûts et simplifier l’élaboration de composants de grande taille. La seconde partie de ce mémoire a permis de montrer que différents types de microstructures, présentant des propriétés mécaniques différentes, peuvent être obtenues par simple mélange de poudre. Ceci est possible par l’utilisation d’un traitement thermique adapté, la variation du taux de zircone et grâce à l’ajout de dopants (Si, Ca et Mg) jouant sur la mobilité des joints de grains d’alumine. Lors de l’utilisation de Ca ou Mg, le taux de zircone et la température ont un effet prépondérant sur l’aspect des microstructures, permettant d’obtenir des micro/micro-composites (< 16vol% de zircone et >1500°C) et nano/nano-composites (25vol% de zircone et T < 1500°C). Seul l’ajout conjoint de Si et de Ca pour des échantillons contenant 2,5vol% de zircone permet de conduire à des micro/nano-composites avec une grande proportion de zircone intragranulaire. Les observations sur des composites avec un taux de zircone proche du taux de percolation (16vol%) permettent de mettre en évidence l’ensemble des types de renforcement observés dans la littérature, en fonction de la température et des dopants utilisés. La variété des microstructures obtenues permet de progresser dans le contrôle des microstructures des composites alumine-zircone, mais aussi d’envisager d’autres applications de ces composites en fonction des mécanismes de renforcement observés et de leurs propriétés mécaniques et structurales. / The aim of this work was to elaborate and characterize zirconia toughened alumina composites with different microstructures, using a simple process. These composites are obtained by colloidal process and are dedicated to orthopedic application. ZTA composites offer both higher strength and toughness than alumina, a lower sensitivity to ageing than zirconia, and also a proven biocompatibility. They open the door to component designs not reachable with other, more brittle materials. Nowadays, these composites are the safest for orthopedic implants application, but can still be improved. The first part of our study is dedicated to a numerical modeling of a large femoral head during sintering. It is so possible to obtain a realistic model of thermal and mechanical strain gradient. However, the modeling should be enhanced by a thorough study of the elastic-viscous-plastic behavior of the composite at high temperature. Then some experiments of sintering with various load or pressure and speed should be practice to determine precisely the sintering related strain. The possibility of machining in the pre-sintered state, with the aim of reducing machining costs and simplify the process of large components, is investigated. The second part is focused on the development of various microstructures with specific mechanical properties and reinforcement behaviors. Such structures were achieved by adjusting the amount of zirconia, controlling the grain growth with dopants to improve or inhibit the alumina grain growth (Si, Ca and Mg), and by adjusting the sintering thermal treatment. The use of calcium associated or not with magnesium seems useless as compared to the predominant influence of the zirconia content. Adjusting zirconia amount led to micro-composites (< 16vol% of zirconia and >1500°C) and nano-composites (25vol% of zirconia and < 1500°C). Only Si/Ca co-doped ZTA composites with small amount of zirconia (2.5vol %) leads to almost homogeneous micro/nano composites with a large proportion of intragranular zirconia particles at high temperature. Around the percolation threshold (16vol% of zirconia) all types of reinforcement mechanisms that could be observed in ZTA composites (referred to literature) can be observed, depending on the thermal treatment and the dopants used. The range of microstructures obtained in this study leads us to investigate other applications for these composites depending of its reinforcement behavior and its mechanical and structural properties.

Dans un objectif de réduction des consommations énergétiques et des impacts environnementaux, la pompe à chaleur (PAC) s'est imposée comme une alternative aux systèmes à combustion fossile pour le chauffage et la production d'eau chaude sanitaire dans les secteurs résidentiel et tertiaire. Les industriels ne cessent de chercher à accroitre la performance énergétique des pompes à chaleur. Toutefois, un phénomène encore mal maitrisé limite les progrès : le givrage. En effet, dans certaines conditions de température et d'humidité de l'air extérieur, du givre peut se former sur la surface de l'évaporateur de la PAC, provoquant ainsi une chute de performance. En France, près de 98 % des PAC du marché utilisent l'air extérieur comme source de chaleur et sont donc exposées à ce phénomène. Malgré des logiques de dégivrage de plus en plus sophistiquées mises en œuvre par les industriels, le fonctionnement cyclique givrage/dégivrage réduit fortement les performances des PAC. Pour optimiser les méthodes de dégivrage, il est nécessaire de comprendre en amont, les mécanismes d'apparition et de croissance du givre. Ce travail de thèse propose ainsi d'étudier la formation et le développement du givre sur une plaque plane refroidie. Une étude approfondie de la bibliographie a permis d'établir des bases de données regroupant des points expérimentaux de l'épaisseur et de la masse volumique du givre. Des modèles et corrélations de formation du givre disponibles dans la littérature ont été reproduits et appliqués à ces bases de données afin d'évaluer la capacité de prédiction de chacun de ces modèles. Les plus performants ont ainsi pu être identifiés. En parallèle, un banc d'essais a été conçu pour observer la formation et la croissance du givre sur une plaque plane. L'étude de sensibilité menée sur la température de l'air, la température de la plaque froide, la vitesse de l'air et l'humidité relative a permis d'évaluer l'impact de ces paramètres sur la formation du givre, et plus particulièrement sur trois de ses propriétés : l'épaisseur, la masse volumique et la conductivité thermique. L'humidité relative et la température de la plaque froide ont été identifiées comme les paramètres prépondérants. Un des résultats importants de ce travail a été de mettre en évidence le rôle de la structure du givre sur ses propriétés (masse volumique et conductivité). Les points expérimentaux obtenus sur le banc d'essais ont été comparés aux résultats issus des modèles de la littérature. Les méthodes de prédiction identifiées comme satisfaisantes dans la partie bibliographique de cette thèse ont fourni des résultats similaires d'un point de vue statistique. Des perspectives de travail ont également été proposées. / In the energy consumption and environmental impact reduction goal, heat pumps emerged as an alternative to fossil fuel systems for space heating and hot water production in residential and tertiary sectors. Manufacturers still try to improve energy performance of heat pumps. However, a non-controlled phenomenon is limiting progress: frosting. Indeed, in some outdoor air temperature and relative humidity conditions, frost can form on the heat pump evaporator surface, leading to performance reduction. On the French market, almost 98 % of the heat pumps are using outdoor air as heat source and are thus affected. Despite more and more sophisticated defrosting strategies, the frosting/defrosting cyclic operation strongly reduces heat pump performance. For optimizing defrosting strategies, there is a need understanding frost appearance and growth mechanisms. This PhD work thus proposes to study frost formation and development on a cold plane plate. An in-depth bibliography study helped establishing databases gathering experimental points on frost thickness and frost density. Models and correlations of frost formation available in the literature have been reproduced and applied to the databases in order to evaluate their prediction capacity. The most performing models have been identified. Meanwhile, an experimental bench allowing visualization of frost formation and development on a cold plane plate has been set up. The sensitivity analysis on air temperature, cold plate temperature, air velocity and relative humidity allowed an evaluation of these parameters impact on frost formation, and more particularly on three of its properties thickness, density and thermal conductivity. Relative humidity and cold plate temperature have been identified as the leading parameters. One of the main results of this work was to highlight the frost crystal structure role on properties (i.e. density and thermal conductivity). Experimental data points obtained with the test bench have been compared to the results provided by literature models. Predictive methods identified as satisfying in the bibliography study gave similar results (from a statistical point of view). Perspectives for future work have also been proposed.