Le passage des médicaments a travers la membrane cellulaire représente souvent une limitation majeur dans un grand nombre de thérapies (anti-cancéreuse, anti-virale par exemple). Des peptides vecteurs connus comme les CPPs (cell penetrating peptides) ont été utilises avec succès pour introduire a l’intérieur des cellules diverses molécules (protéines, peptides, siRNA, quantum dots) et présentent un fort potentiel dans l'adressage de médicaments. Parmi les différents CPPs décrits dans la littérature la plupart sont des peptides basiques ou amphiphiles.Nous nous sommes intéressés a l'utilisation d’oligomères non charges construits a partir de motifs contraints mimes de dipeptides comme vecteurs de pénétration cellulaire. L'internalisation cellulaire et leur localisation ont été établies a l'aide de dérivés fluorescents par microscopie confocale. L' étude de pénétration cellulaire par mesure de fluorescence a montre que des oligomères de (3S)-amino-5-carbonylmethyl-2,3-dihydro-1,5-benzothiazepine-4(5H)-one] (DBT) sont aussi puissants que les oligomères d'arginine (oligoArg), vecteurs de référence. Par microscopie confocale nous avons montré que ces composés sont internalisés dans les lysosomes. L’efficacité d'internalisation de nos composés a été confirmé par une méthode de quantification par spectrométrie de masse MALDI-TOF développée dans notre groupe. Cette méthode repose sur l'utilisation conjointe d'un marqueur UV-absorbant dérivé de l'acide alfa-cyano-4-hydoxycinnamique (HCCA) et d'une matrice MALDI adaptée. Un effet important de discrimination spectrale est obtenu, permettant une amplification du signal de la molécule d' intérêt dans un mélange complexe. Ainsi les faibles concentrations internalisées peuvent être détectées. Grâce a cette technique et l'utilisation d'un étalon deutéré, nous avons calculé la concentration intracellulaire de deux CPP de référence l'octa-arginine et la pénétratine. Nous avons aussi étudier l’internalisation de petits oligomères construits a partir d'acide 2-aminomethyl-phenyl-acetique (AMPA). Par microscopie confocal nous avons constaté que ces petits oligomères sont internalisés par voie endo-lysosomale.L’efficacité de la pénétration cellulaire de ces petits oligomères aromatiques (oligoAMPA et oligoDBT) offre une nouvelle classe de vecteurs qui ont la particularité d’être non-cationiques et hydrophobes. De tels composés pourraient être utilisés pour la délivrance de médicaments dans le traitement des maladies comme le cancer, les maladies lysosomales ou la maladie d'Alzheimer. Afin de montrer que cette nouvelle classe de vecteurs est capable d'internaliser des composés biologiquement actifs, nous les avons associés a un inhibiteur puissant de la Cathepsine D (CD) la pepstatine. CD est une endopeptidase lysosomale qui dans des conditions normales est localisée dans les endosomes et les lysosomes. Pour certains cancers, la CD est surexprimée et secrétée a l’extérieur de la cellule. La CD est probablement impliquée dans la prolifération des cellules cancéreuses par l'activation de certains facteurs de croissances dans les endosomes. La pepstatine est une inhibiteur puissant de la CD. Cependant son efficacité thérapeutique potentielle est limitée par une faible capacité de pénétration des membranes cellulaires et une faible solubilité nécessitant de fortes doses pour l'inactivation de la CD in vitro et in vivo. Afin d’améliorer son efficacité et sa biodisponibilité, des conjugues de la pepstatine avec nos vecteurs de pénétration cellulaire, oligo (AMPA)4 et (DBT)4, et une partie solubilisante ont été développés. Certains de ces bioconjugués ont montre une toxicité élevée (IC50 = 2.10-6) in vitro sur différentes lignées cellulaires tumorales. Des tests in vivo sur des souris sont prévus pour le futur. / As a part of a program for foldamer design two ¦Â-turn mimetics (3S)-amino-5-(carboxylmethyl)-2,3-dihydro-1,5-benzothiazepin-4(5H)-one or DBT and 2-aminomethyl-phenyl-acetic acid or AMPA were selected as frameworks from a molecular modeling study for their suitability to adopt helical structure. At first we developed a highly efficient scale up synthesis of the DBT moiety protected by 9-fluorenylmetoxycarbonyl (Fmoc) group. By standard solid phase peptide synthesis (SPPS) we synthesized DBT oligomers of different lenghts and modifications were introduced at their N-terminus. Our first task was to perform structural analysis of the oligomers by NMR and X-Ray. Numerous NOE interactions in the DBT pentamer and hexamer molecules were detected by NMR 2D NOESY experiments. These data strongly suggest the organization of these DBT oligomers. Small crystals were obtained from the same molecules in DMSO but at the time being their size is not importan t enough for X-Ray crystallography studies. In a parallel study we hypothesized that short oligomers constructed by DBT or AMPA frameworks could translocate the cellular membrane and could be used as new cell penetrating non-peptides - CPNP. Even though these compounds are not charged as most cell penetrating peptides (CPP)5 or CPNP, we considered that by virtue of their aromaticity, hydrophobicity and their well-organized structure they could have a non-specific interaction with the lipid bilayer and thus be internalized into the cell. Short oligomers were synthesized on Rink amide (RA) resin following SPPS methodology and labelled at their N-terminus with fluorescein isothiocyanate (FITC). At first the cellular uptake of the (DBT)2-4 oligomers in MDA-MB-231 breast cancer cells was analyzed by fluorescence emission measurement and compared to the potent and well-studied CPP octa-arginine (Arg)8 as a positive control and carboxyfluorescein as a negative control. The highest intracellular fluorescence intensity was found for (DBT)4 with a drastic decrease (>4-times) for (DBT)3 and (DBT)2 oligomers. Thus, the cellular uptake appeared length-dependent with an increase of the internalization with the oligomer size. Moreover, the amount of (DBT)4 that was internalized was more significant than that of (Arg)8 despite the fact that it is uncharged. By confocal microscopy we determined that (DBT)4 is mainly localized in the endosomes after 3 hours of incubation and in the lysosomes after 16 hours of incubation. Altogether, these data indicate the ability of these oligomers to target the endolysosomal pathway. Although most of the initial drug delivery studies aimed to avoid lysosomal addressing to prevent subsequent drug degradation, more recent studies demonstrated the relevant clinical utility to target this compartment for drug delivery in the treatment of lysosomal storage diseases, Alzheimer¡¯s disease, and cancer.While analyzing the internalization efficiency of our CPNP we decided to straightforward evaluate their concentration inside the cells. We studied our compounds internalization by total fluorescence emission measurement and by confocal microscopy but none of these techniques gave us the possibility to determine the exact amount of compound internalized per cell. A study reported by Burlina et al. brought a great improvement in proposing a highly reproducible quantification method based on MALDI-TOF MS to measure the concentration of the internalized peptides. However, after cell lysis, this method requires the capture of the biotin-labelled CPP by streptavidin coated magnetic beads. This step is particularly critical for the accuracy of the quantification. This is the reason why we decided to develop a new general methodology based on MALDI-TOF mass spectrometry (MS) which does not require any purification or separation steps. We studied the internalization of CPP/CPNP compou nds by using an UV light-absorbing tag alpha-cyano-4-hydroxycinnamic acid (HCCA) and preparing the samples in a neutral matrix such as alpha-cyano-4-hydroxycinnamic methyl ester (HCCE). This combination (HCCA tag and HCCE matrix) enabled us to discriminate MS signals induced by peptides of interest that were present in low concentration from those of unlabelled more abundant peptides. By addition of a precise amount of deuterated-HCCA-tagged CPP/CPNP prior the MALDI TOF MS experiment, the internalized CPP/CPNP could be quantified on the basis of the ratio between the [M+H]+ peaks of the deuterated and nondeuterated HCCA-tagged CPP.Another direction for research was to synthesize bioconjugates between our newly discovered CPNP and some biologically active compounds that are unable to cross the cell membrane. We selected pepstatine which is a powerful transition state inhibitor of the Cathepsin D (CD). Pepstatine while a very potent inhibitor of the CD is unable to cross the cellular membrane. Moreover pepstatine activity in vitro or in vivo is hampered by its poor solubility in water. CD is a soluble lysosomal aspartic endopeptidase synthesized in rough endoplasmic reticulum as preprocathepsin D (pCD).12 Upon entering the acidic endosomal and lysosomal compartments proteolytic cleavages of the pCD result in the formation of the active enzymatic form of CD. Under normal physiological conditions pCD is sorted to the lysosomes and found intracellularly but in some pathological and physiological conditions like cancer pCD/CD escape the normal targeting mechanism and is secreted from the cell. Once secreted to the outside, pCD can be endocytosed via M6PR or yet unknown receptor by both cancer cells and fibroblasts. The endocytosed pCD undergoes maturation into the enzymatically active CD. An enzymatic activity of CD outside of the cell or inside the endosomes could be responsible for the activation of several growth factors and growth factor receptors. Several groups have proven that the tumour growth is not inhibited by the powerful CD inhibitor pepstatine. These results exclude the importance of the CD enzymatic activity outside of the cell but as already mentioned pepstatine is unable to penetrate into the cell thus CD activation of growth factors inside the endosomes or the lysosomes is still a possibility. Different CPNP-Pepstatine conjugates were synthesized and tested in vitro for their ability to inhibit MDA-MB-231 breast cancer cells growth. Some of these conjugates showed high cytotoxicity, probably via a Cathepsin D inhibition in the endosomes or the lysosomes. One o f the most potent tested compounds was JMV4463. This compound was obtained by the conjugation of pepstatine with a CPNP as delivery system (AMPA4) and with solubilizing moiety composed of polyethylene glycol and D-Arginine residue. The good in vitro results obtained with the vectorized pepstatine encouraged us to perform in vivo tests. We performed scale up synthesis of JMV4463 in order to obtain enough product for anti-cancer activity on mice in the near future.

O objetivo deste estudo foi avaliar a técnica de espectrometria de massas por ionização/dessorção a laser assistida por matriz tempo-de-vôo (MALDI-TOF) para a identificação direta em amostras de leite (sem cultivo microbiológico) de bactérias causadoras de mastite. Para tanto foram realizados dois experimentos (1 e 2). No experimento 1, o objetivo foi determinar a sensibilidade diagnóstica da técnica MALDI-TOF MS para a identificação direta em amostras de leite de Staphylococcus aureus, Streptococcus uberis, Streptococcus agalactiae, Streptococcus dysgalactiae e Escherichia coli. Foram realizadas contaminações experimentais de S. aureus, S. uberis, S. agalactiae, S. dysgalactiae e E. coli em amostras de leite, para a obtenção de contagens de 103 a 109 ufc/mL. As amostras de leite contaminadas foram processadas com o uso do kit Maldi Sepsityper® (Bruker Daltonics) e submetidas ao protocolo de lise bacteriana para posterior análise por MALDI-TOF MS. Espectros de massas foram coletados na faixa de massas de 2.000-20.000 m/z e foram analisados pelo programa MALDI Biotyper 3.0 (Bruker Daltonics) com as configurações padrão para obtenção da identificação bacteriana. A identificação direta de patógenos causadores de mastite a partir de amostras de leite foi possível em contagem ≥106 ufc/mL para S. aureus, ≥107 ufc/mL para E. coli, e ≥108 ufc/mL para S. agalactiae, S. dysgalactiae e S. uberis. No experimento 2, o objetivo foi avaliar o efeito da pré-incubação de amostras de leite de quartos mamários com mastite subclínica sobre a eficácia da identificação sem cultivo de patógenos causadores de mastite por MALDI-TOF MS. Foram selecionados 2 rebanhos leiteiros para coletas de leite de quartos mamários de todas as vacas em lactação. As amostras de leite foram submetidas às análises de: a) cultura microbiológica; b) pré-incubação seguida de identificação por espectrometria de massas diretamente do leite; c) contagem bacteriana total (CBT). Para a realização da CBT, as amostras de leite foram submetidas à citometria de fluxo; e para a identificação direta de patógenos causadores de mastite a partir do leite, as amostras foram submetidas ao desnate por centrifugação (10.000 Xg por 10 minutos), e pré-incubação a 37ºC por 12 horas. Posteriormente, as amostras foram processadas com o uso do kit Maldi Sepsityper® (Bruker Daltonics) e submetidas ao protocolo de lise bacteriana para posterior análise por MALDI-TOF MS. Do total de 810 amostras de leite analisadas por cultura microbiológica (método referência), 347 apresentaram crescimento bacteriano, sendo 305 identificadas como agentes de interesse na identificação direta pelo método MALDI-TOF MS: Staphylococcus coagulase negativa (n=191), S. aureus (n=31), S. agalactiae (n=42), S. uberis (n=37), S. dysgalactiae (n= 4). Sendo assim, 305 amostras foram analisadas pelo método de idenfificação direta MALDI-TOF MS, a qual apresentou baixa sensibilidade quando comparado com a cultura microbiológica (método referência): Staphylococcus coagulase negativa (14,08%), S. agalactiae (15,25%), S. uberis (1,69%) S. aureus (6,12%) e S. dysgalactiae (0%). A pré-incubação de amostras de leite não aumentou a sensibilidade de identificação direta de microrganismos causadores de mastite pelo método MALDI-TOF MS. / The purpose of the present study was to evaluate the technique of mass spectrometry by desorption / ionization assisted laser array time-of-flight (MALDI-TOF MS) for the direct identification in milk samples (no microbiological culture) of mastitis causing bacteria. Therefore, we carried out two experiments (1 and 2). In experiment 1, we determined the diagnostic sensitivity of MALDI-TOF MS technique for the direct identification in milk samples of Staphylococcus aureus, Streptococcus uberis, Streptococcus agalactiae, Streptococcus dysgalactiae and Escherichia coli. Experimental contamination of S. aureus, S. uberis, S. agalactiae, S. dysgalactiae and E. coli in samples of milk to a concentration of 103-109 cfu/mL were performed. The contaminated milk samples were processed using kit Maldi Sepsityper® (Bruker Daltonics) and subjected to bacterial lysis protocol for analysis by MALDI-TOF MS. Mass spectra were collected in the mass range of 2000-20000 m/z and were analyzed by MALDI Biotyper 3.0 software (Bruker Daltonics) with default settings to obtain bacterial identification. Direct identification of mastitis causing pathogens from milk samples was possible at ≥106 cfu/mL for S. aureus, ≥107 cfu/mL for E. coli and ≥108 cfu/mL for S. agalactiae, S. dysgalactiae and S. uberis. In experiment 2, the objective was to evaluate the effect of pre-incubation of milk samples from mammary quarters with subclinical mastitis on the effectiveness of identification without cultivation, of mastitis-causing pathogens by MALDI-TOF MS. We selected mammary quarter milk samples from all lactating cows on two dairy herds. The milk samples were subjected to analyzes of: a) microbiological culture; b) pre-incubation followed by identification by mass spectrometry directly from milk; c) total bacterial count (TBC). Flow cytometry was used to determine TBC and; to directly identify the mastitis-causing pathogens from milk, fat was separated by centrifugation (10,000 Xg for 10 minutes) and; samples were pre-incubated at 37°C for 12 hours. Subsequently, the skim milk samples were submitted to kit Maldi Sepsityper® (Bruker Daltonics) and to the bacterial lysis protocol for analysis by MALDI-TOF MS. A total of 810 milk samples were analyzed by microbiological culture (reference method), of which 347 showed bacterial growth. Considering all culture positive samples 305 were identified as agents of interest in the direct identification by MALDI-TOF MS method: coagulase negative staphylococci (n = 191), S. aureus (n = 31), S. agalactiae (n = 42), S. uberis (n = 37) and S. dysgalactiae (n = 4). Therefore, 305 samples were directly identified by MALDI-TOF MS, which presented low sensitivity when compared to microbiological culture (Reference method): coagulase-negative staphylococci (14.08%), S. agalactiae (15.25 %), S. uberis (1.69%), S. aureus (6.12%) and S. dysgalactiae (0%). Pre-incubation of milk samples did not increase the sensitivity of the MALDI-TOF MS method directly identify mastitis-causing microorganisms.

Au cours des dernières anneés, la taxonomie bactérienne a subi de profonds changements mais peu de consensus existent quant à la description précise des procaryotes. La diversité des procaryotes a été estimeé à 107 espèces, et la classification actuelle contient plus de 12 900 espèces officiellement reconnues. Ceci souligne l'absence d'un répertoire des procaryotes isolés chez l'homme. Nous avons constitué ce répertoire qui contient 2 156 espèces différentes réparties en 12 phyla,Notre second travail est la caractérisation du microbiote digestif par 5 approches varieés (cytométrie de flux, coloration de gram, TEM, qPCR, pyroséquençage). Nous avons analysé 16 selles de patients en comparant le taux de procaryotes de type gram positif/négatif. La moitié des procaryotes de type gram négatif n'est pas détecté par le pyroséquençage,alors qu'ils sont décrits comme les constituants majeurs de ce microbiote d'après les 1ères études réaliseés utilisant la culture.Dans notre 3ème travail, nous avons voulu montrer que l'utilisation de la culture bactérienne n'est pas inférieure aux techniques de séquençage pour étudier la diversité du microbiote digestif. Au total, depuis 4 ans, 685 échantillons ont été analysés et plus de 500 000 colonies ont été identifieés par MALDI-TOF. Ce travail a permis d'augmenter de 77,5 % le nombre d'espèces identifieés dans le tube digestif. Les nouvelles espèces sont décrites suivant le concept « taxonogenomics » incluant des donneés phénotypiques et le séquençage du génome. / Bacterial taxonomy has undergone tremendous changes over time, with little historical consensus regarding specific descriptions of prokaryotes. The prokaryotes have been estimated about 107 species, and the current classification contained more than 12,900 species. This highlights the absence of an exhaustive and specific database listing all prokaryotes associated with humans. We found than the human prokaryotic repertoire contained 2,156 species, divided among 12 different phyla.The second aim of our work was to characterize the human gut microbiota using 5 different techniques, including morphologic and molecular approaches (flow cytometry, gram staining, electron microscopy, qPCR and pyrosequencing). We analyzed 16 stools samples of patient and we copared the rate of gram-positive and gram-negative prokaryotes obtained with each technique. We found than by pyrosequencing only a half of gram-negative prokaryotes was detected.Our third goal was to demonstrate that bacterial culture was not inferior to pyrosequencing to describe the gut diversity. Culturomics concept created during the pioneer study has revolutionized the approach of the microbiota exploration. Since 4 years, we have performed the analyze of 685 different samples and identified more than 500,000 colonies using the MALDI-TOF mass spectrometry. We have increased by 77.5% the number of species isolated in the gut. Each new species will be described following our new concept named "taxonogenomics", including phenotypic data and genome sequencing.

La Tomographie par Emission de Positrons (TEP) est une technique d’imagerie médicale utilisée largement dans le traitement du cancer et dans la recherche neurobiologique, afin d’imager l’activité biologique des organes. Il s’agit de détecter deux photons de 511 keV produits par l’annihilation d’un positron dans les tissus, ce qui permet d’en reconstruire la carte 3D. En mesurant avec une très bonne précision la différence de temps de détection des deux photons, il sera possible d’améliorer la qualité d’image (technique du temps de vol). Dans ce manuscrit, nous présentons le développement de deux détecteurs innovants, rapides et efficaces, pour la détection de la lumière Cherenkov produite par la conversion des photons de 511 keV. Le premier, destiné à un scanner clinique (cerveau) et pré-clinique à haute précision spatiale, utilise comme milieu de détection du TriMéthylBismuth. Le second, pouvant être utilisé pour construire un scanner corps entier, met en œuvre un cristal de PbF₂ comme radiateur Cherenkov. Dans les deux configurations, un photomultiplicateur à micro-canaux (MCP-PMT) est utilisé pour détecter les photons Cherenkov. Notre électronique de détection montre une résolution temporelle limitée à 5 ps (RMS). La chaîne de détection est limitée par les performances du MCP-PMT. Après étalonnage, nous avons mesuré une efficacité de 25 % (grande pour un détecteur Cherenkov), et de résolution temporelle de 200 ps (FWHM).Nous exposons les facteurs limitant la résolution temporelle des détecteurs et proposons des développements qui permettront d’en améliorer les performances. / Positron Emission Tomography (PET) is a nuclear imaging technique widely used in oncology and neuroscience to observe biological activity in the body. Detection of two gamma quanta with the energy 511 keV emitted by positron annihilation in tissues allows one to reconstruct the tracer activity distribution in the body of the patient. Additional measurement of the difference in time detection between the two photons lets us to improve significantly the quality of the reconstructed image (time-of-flight method).In this manuscript, we present the development of two innovative detectors, fast and efficient, used to detect Cherenkov light produced by electrons from the photo-ionization conversions of 511 keV gamma quanta. The first one, intended for use in a brain PET scanner of a high spatial resolution, uses TriMethylBismuth for the detection medium. The second one, planned to be used to construct a whole-body PET scanner, enforces a PbF₂ crystal as Cherenkov radiator. In both configurations a micro-channel photo-multiplier (MCP-PMT) is used to detect Cherenkov photons. We commissioned an electronic detection chain with a time resolution limited to 5 ps (RMS). Using precise MCP-PMT calibration, we were able to develop simultaneously detectors with high efficiency, up to 25 %, and time resolution as good as 200 ps (FWHM).We highlight the limitations of detectors time resolution and suggest several developments in order to improve performances of Cherenkov light detectors.

Die klassische Identifizierung von obligat anaeroben Bakterien ist mit einem hohen Labor- und Zeitaufwand verbunden. Um festzustellen, ob die Identifizierung mittels Matrix-unterstützter Laser-Desorption/Ionisation und Massenspektrometrie mit Flugzeitanalysator (Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry; MALDI-TOF MS) ein Verfahren ist, um obligate Anaerobier eindeutig zu identifizieren, wurde mit der vorliegenden Arbeit die Identifizierung von unterschiedlichen Spezies der B. fragilis Gruppe mittels MALDI-TOF MS untersucht. Hierfür wurden 105 obligate Anaerobier der B. fragilis Gruppe aus der Stammsammlung des Institutes für Medizinische Mikrobiologie und Infektionsepidemiologie der Universität Leipzig untersucht. Es fanden sich für die untersuchten Erreger Spektren mit sehr guter Auflösung. Eine Identifizierung und Differenzierung war eindeutig möglich. Unter Verwendung dieser Daten wurde eine Referenzdatenbank erstellt. Die erhaltenen Ergebnisse wurden mittels einer verblindeten Studie überprüft, wobei 52 von 53 (98,1%) der untersuchten Stämme eindeutig identifiziert werden konnten. Dies schließt ebenfalls die Identifizierung und Differenzierung von 15 Metronidazol-sensiblen/ Enterotoxin-negativen, 8 Metronidazol-resistenten/ Enterotoxin-negativen und 8 Metronidazol-sensiblen/ Enterotoxin-positiven B. fragilis Stämmen ein. Die Identifizierung mittels MALDI-TOF MS ist somit eine zuverlässige Methode zur Identifizierung von obligaten Anaerobiern der B. fragilis Gruppe. Weiterhin finden sich Hinweise, dass ein Nachweis von Resistenz-, Virulenz- und Pathogenitätsfaktoren mittels MALDI-TOF MS bei diesen Erregern möglich ist.

Die klassische Identifizierung von obligat anaeroben Bakterien ist mit einem hohen Labor- und Zeitaufwand verbunden. Um festzustellen, ob die Identifizierung mittels Matrix-unterstützter Laser-Desorption/Ionisation und Massenspektrometrie mit Flugzeitanalysator (Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry; MALDI-TOF MS) ein Verfahren ist, um obligate Anaerobier eindeutig zu identifizieren, wurde mit der vorliegenden Arbeit die Identifizierung von unterschiedlichen Spezies der B. fragilis Gruppe mittels MALDI-TOF MS untersucht. Hierfür wurden 105 obligate Anaerobier der B. fragilis Gruppe aus der Stammsammlung des Institutes für Medizinische Mikrobiologie und Infektionsepidemiologie der Universität Leipzig untersucht. Es fanden sich für die untersuchten Erreger Spektren mit sehr guter Auflösung. Eine Identifizierung und Differenzierung war eindeutig möglich. Unter Verwendung dieser Daten wurde eine Referenzdatenbank erstellt. Die erhaltenen Ergebnisse wurden mittels einer verblindeten Studie überprüft, wobei 52 von 53 (98,1%) der untersuchten Stämme eindeutig identifiziert werden konnten. Dies schließt ebenfalls die Identifizierung und Differenzierung von 15 Metronidazol-sensiblen/ Enterotoxin-negativen, 8 Metronidazol-resistenten/ Enterotoxin-negativen und 8 Metronidazol-sensiblen/ Enterotoxin-positiven B. fragilis Stämmen ein. Die Identifizierung mittels MALDI-TOF MS ist somit eine zuverlässige Methode zur Identifizierung von obligaten Anaerobiern der B. fragilis Gruppe. Weiterhin finden sich Hinweise, dass ein Nachweis von Resistenz-, Virulenz- und Pathogenitätsfaktoren mittels MALDI-TOF MS bei diesen Erregern möglich ist.

No description available.

<p>This study reports on a proteomic analysis of sorghum proteomes in response to salt and hyperosmotic stresses. Two-dimensional gel electrophoresis (2DE) in combination with mass spectrometry (MS) was used to separate, visualise and identify sorghum proteins using both sorghum cell suspension cultures and whole plants. The sorghum cell suspension culture system was used as a source of culture filtrate (CF) proteins. Of the 25 visualised CBB stained CF spots, 15 abundant and well-resolved spots were selected for identification using a combination of MALDI-TOF and MALDI-TOFTOF MS, and database searching. Of these spots, 14 were positively identified as peroxidases, germin proteins, oxalate oxidases and alpha-galactosidases with known functions in signalling processes, defense mechanisms and cell wall metabolism.</p>

<p>This study reports on a proteomic analysis of sorghum proteomes in response to salt and hyperosmotic stresses. Two-dimensional gel electrophoresis (2DE) in combination with mass spectrometry (MS) was used to separate, visualise and identify sorghum proteins using both sorghum cell suspension cultures and whole plants. The sorghum cell suspension culture system was used as a source of culture filtrate (CF) proteins. Of the 25 visualised CBB stained CF spots, 15 abundant and well-resolved spots were selected for identification using a combination of MALDI-TOF and MALDI-TOFTOF MS, and database searching. Of these spots, 14 were positively identified as peroxidases, germin proteins, oxalate oxidases and alpha-galactosidases with known functions in signalling processes, defense mechanisms and cell wall metabolism.</p>

<p>This study reports on a proteomic analysis of sorghum proteomes in response to salt and hyperosmotic stresses. Two-dimensional gel electrophoresis (2DE) in combination with mass spectrometry (MS) was used to separate, visualise and identify sorghum proteins using both sorghum cell suspension cultures and whole plants. The sorghum cell suspension culture system was used as a source of culture filtrate (CF) proteins. Of the 25 visualised CBB stained CF spots, 15 abundant and well-resolved spots were selected for identification using a combination of MALDI-TOF and MALDI-TOFTOF MS, and database searching. Of these spots, 14 were positively identified as peroxidases, germin proteins, oxalate oxidases and alpha-galactosidases with known functions in signalling processes, defense mechanisms and cell wall metabolism.</p>