Emergence of drug resistance is a major problem in the treatment of many diseases including tuberculosis. To tackle the problem, it is essential to obtain a global perspective of the molecular mechanisms by which bacteria acquire drug resistance. Systems biology approaches therefore become necessary. This work aims to understand pathways to drug resistance and strategies for inhibition of the resistant strains by using a combination of experimental genomics and computational molecular systems approaches. Laboratory evolution of Mycobacterium smegmatis MC2 155 by treatment with isoniazid (INH), a front-line anti-tubercular drug, resulted in a drug-resistant strain (4XR), capable of growth even at about 10-times the minimum inhibitory concentration of the drug. Whole genome sequence of the 4XR was determined, which indicated only 31 variations in the whole genome, including 3 point mutations, 17 indels and 11 frame-shifts. Two mutations were in proteins required for the pharmacological action of the drug, albeit in regions distant from the drug binding site. The variations however were insufficient to explain the observed resistance to isoniazid. For a better understanding of the global changes associated with drug resistance, whole genome-wide gene expression data was obtained for the resistant strain and compared with that of the WT strain. 716 genes were found to be differentially regulated in 4XR, spanning different biochemical, signaling and regulatory pathways. From this, some explanations for the emergence of drug resistance were obtained, such as the up-regulation of the enzymes in the mycolic acid biosynthesis pathway and also of the drug efflux pumps. In addition, enrichment analysis indicated that up-regulated genes belong to functional categories of response to stress, carbohydrate metabolism, oxidation-reduction process, ion transport, signaling as well as lipid metabolism. The differential gene regulations seemed to be partially responsible for conferring the phenotype to the organism. Alterations in the metabolic pathways in 4XR were characterized using the phenotypic microarray technology, which experimentally scanned the respiratory ability of the resistant bacteria under 280 different nutrient conditions and 96 different inhibitors. Phenotypic gain, where the resistant strain grows significantly better than the wild type and phenotypic loss, where the growth of the resistant strain is compromised as compared to the sensitive strains were derived from the comparison of the phenotypic responses. Differences in survival ability and growth rates in different nutrient sources in the resistant phenotype as compared to the wild type were observed, suggesting rewiring in the metabolic network of the drug-resistant strain. In particular, the pathways of central carbon metabolism and amino acid biosynthesis exhibit significant differences. The strain-specific metabolic pathway differences may guide in devising strategies to tackle the drug-resistant strains selectively and in a rational manner. Scanning electron microscopy indicated the morphology of the drug-resistant strains to be significantly altered, as compared to the control drug-sensitive strain. It is well-known that isoniazid acts by inhibiting mycolic acid biosynthesis. The pathway turns out to be a target for many other anti-tubercular drugs also, since mycolic acids are major components of the cell wall. It is therefore important to understand what changes occur in the mycolic acid and the associated pathways in the drug-resistant variety so that strategies to tackle the latter can be chosen more judiciously. The lipidome of the cell wall was therefore quantitatively characterized by mass spectrometric analyses, which indeed confirmed that the 4XR strain has a significantly different composition profile. Among the six categories of lipids, the members of the glycerophospolipids category were abundant while the fatty acyls, polyketides and saccharolipids were lower in the 4XR strain as compared to the WT. The lipidomic data derived from the cell wall of INH-resistant strain shows that it results in the mycolic acid pathway function restoration, which would otherwise be lost upon drug exposure in the sensitive strain. Understanding the precise changes that occur in the lipidome in the drug-resistant strains is expected to be useful in developing new ways to tackle resistance. Next, to understand the implications of altered gene expression profiles, protein-protein interaction networks are constructed at a genome-scale that captures various structural and functional associations mediated by proteins in the mycobacterial cell. Using transcriptome data of 4XR, a response network is computed. Using an algorithm previously developed in the laboratory, the networks have been mined to identify highest differential activity paths and possible mechanisms that are deployed by the cells leading to drug resistance. Known resistance mechanisms such as efflux, cytochromes, SOS, are all seen to constitute the highest activities for achieving drug resistance in 4XR. Interestingly, such paths are seen to form a well-connected subnet, indicating such differential activities to be orchestrated. This clearly shows that multiple mechanisms are simultaneously active in the 4XR and may together generate drug resistance. Mechanisms of detoxification and antioxidant responses are seen to predominate in the 4XR subnet. Overall the analysis provides a shortlist of strategies for targeting the drug resistant strain. Next, the phenotypic microarray platform was used for screening for growth in Msm in the presence of various drugs. Data analysis and clustering resulted in identification of conditions that lead to phenotypic gain or loss in the 4XR as well as those that lead to differential susceptibility to various drugs. Drugs such as cephalosporins, tobramycin, aminotriazole, phenylarsine oxide, vancomycin and oxycarboxin were also found to inhibit growth in the resistant strain selectively. In other words, the 4XR is found to be collaterally sensitive to these drugs. The top-net formed by the highest differential activity paths, identified from the network described earlier has already indicated the involvement of proteins that generate antioxidant responses. Insights from the two methods, first from the targeted approach and second, from the phenotypic discovery approach were combined together to select only those compounds to which the 4XR strain was collaterally sensitive and targeted proteins responsible for antioxidant responses. These compounds are vancomycin, phenylarsine oxide, ebselen and clofazimine. These were further tested against the virulent M. tuberculosis H37Rv strain in a collaborator‘s laboratory. 3 of these compounds such as vancomycin, ebselen and phenylarsine oxide were found to be highly active in combinations with isoniazid against all tested Mtb strains, showed high levels of inhibition against H37Rv and 3 different single drug resistant, MDR and XDR strains. Moreover, they were observed to be highly potent when given in combinations. Clofazimine on the other hand, in combination with isoniazid showed activity but no significant synergy in the virulent drug-resistant strains of M. tuberculosis though synergistic to the sensitive strain. Thus, experiments with M. tuberculosis provide empirical proof that four different compounds, all capable of blocking antioxidant responses, are capable of inhibiting growth of single-, multiple- and extremely-drug-resistant clinical isolates of M. tuberculosis. Using transcriptome data from literature for M. tuberculosis exposed to six different drugs, similar drug specific response networks were constructed. These networks indicate differences in the cellular response to different drugs. Interestingly, the analysis suggests that different drug targets and hence different drugs could trigger drug resistance to various extents, leading to the possibility of prioritizing drug targets based on their resistance evolvability. An earlier study from the laboratory suggested the concept of target-co-target pairs, where-in the co-target could be a key protein in mediating drug resistance for that particular drug and hence for its target protein. Top ranked hubs in multiple drug specific networks such as PolA, FadD1, CydA, a monoxygenase and GltS, can possibly serve as co-targets. Simultaneous inhibition of the co-target along with the primary target could lower the chances of emergence of drug resistance. Such analyses of drug specific networks provide insights about possible routes of communication in the cell leading to drug resistance and strategies to inhibit such communication to retard emergence of drug resistance. Since mutations in the target proteins are known to form an important mechanism by which resistant strains emerge, an understanding of the nature of mutations in different drug targets and how they achieve resistance is crucial. Sequence as well as structural bases for the resistance from known drug-resistant mutants in different drug targets is deciphered and then positions amenable to such mutations are predicted in each target. Mutational indices of individual residues in each target structure are computed based on sequence conservation. Saturated mutagenesis is performed in silico and structural stability analysis of the target proteins has been carried out. Critical insights were obtained in terms of which amino acid positions are prone to acquiring mutations. This in turn suggests interactions that are not desirable, thus can be translated into guidelines for modifying the existing drugs as well as for designing new drugs. Finally, the work presented here describes application of the systems biology approaches to understand the underlying mechanisms of drug resistance, which has provided insights for drug discovery on multiple fronts though target identification, target prioritization and identification of co-targets. In particular, the work has led to a rational exploration of collateral drug sensitivity and cross-resistance of the drug-resistant strain to other compounds. Combinations of such compounds with isoniazid were first identified in the M. smegmatis model system and later tested to hold good for the virulent M. tuberculosis strain, in a collaborative study. The combinations were found to be active against three different clinical drug-resistant isolates of M. tuberculosis. Therefore, this study not only reveals the global view of resistance mechanisms but also identifies synergistic combinations of promising drug candidates based on the learnt mechanisms, demonstrating a possible route to exploring drug repurposing. The combinations are seen to work at a much reduced dosage as compared to the conventional tuberculosis drug regimens, indicating that the toxicity and any associated adverse effects may be greatly reduced, suggesting that the combinations may have a high chance to succeed in the next steps of the drug discovery pipeline.

Made available in DSpace on 2014-07-29T15:30:44Z (GMT). No. of bitstreams: 1 dissertacao eduardo martins de sousa med trop.pdf: 881180 bytes, checksum: dec3e190185b786a8f3ab68beeafdecb (MD5) Previous issue date: 2009-02-11 / Atypical mycobacteria are microorganism s appart from the etiological agents responsible for tuberculosis and leprosy. They are currently considered as emerging pathogens associated with simple surgical procedures, and are resistant to conventional antibiotics. The atypical mycobacterial infections is responsible for three in every 10 thousand people per year, but the incidence has been increasing as the number of individuals infected with HIV also increases. The low virulence of atypical mycobacteria associates its pathogenicity to decreased resistance of the host, and consequently it is necessary to better understand the interaction between host and microorganism. The cellular and humoral immune response of BALB/c mice and C57BL/6 mice infected with M. massiliense isolated from an outbreak of hospitals in the city of Goiania was evaluated. The isolate of M. massiliense used in this study was able to infect immunocompetent mice, which completely controlled the bacterial load before the 30 days of infection. The mechanisms by which these animals cleared the mycobacteria were: production of NO by peritoneal macrophages, presence of specific IgG1 and induction of mRNA for inflammatory cytokines, as well as regulatory cytokines in inflammation. / Micobactérias atípicas são microrganismos distintos dos agentes etiológicos responsáveis pela tuberculose e pela lepra (Hanseníase). São considerados atualmente como patógenos emergentes associados a procedimentos cirúrgicos simples, e são resistentes aos antibióticos convencionais. As infecções por micobacterias atípicas atingem três em cada 10 mil pessoas por ano, porém a incidência vem aumentando à medida que cresce o número de indivíduos infectados por HIV. A baixa virulência das micobactérias atípicas condiciona a sua patogenicidade à diminuiçäo da resistência do hospedeiro, por isso faz-se necessário uma melhor investigação da interação do microrganismo com o hospedeiro. Nesta dissertação, a resposta imune celular e humoral de camundongos BALB/c e C57BL/6 frente à infecção por M. massiliense isolada de surto hospitalar na cidade de Goiânia foi avaliada. O isolado de M. massiliense utilizado neste estudo foi capaz de infectar camundongos imunocompetentes, que controlaram completamente a carga bacteriana antes dos 30 dias de infecção. Os mecanismos pelos quais estes animais eliminaram as micobactérias foram: produção de NO por macrófagos peritoneais, presença de IgG1 específica e indução de mRNA para citocinas inflamatórias, assim como de citocinas reguladoras da inflamação.

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2016-05-20T11:06:25Z No. of bitstreams: 2 Dissertação - Rogerio Coutinho das Neves - 2015.pdf: 6048850 bytes, checksum: 1bac6d1d4aa28a3cf0ebbb228b593986 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-05-20T11:12:51Z (GMT) No. of bitstreams: 2 Dissertação - Rogerio Coutinho das Neves - 2015.pdf: 6048850 bytes, checksum: 1bac6d1d4aa28a3cf0ebbb228b593986 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2016-05-20T11:12:51Z (GMT). No. of bitstreams: 2 Dissertação - Rogerio Coutinho das Neves - 2015.pdf: 6048850 bytes, checksum: 1bac6d1d4aa28a3cf0ebbb228b593986 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2015-02-27 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Outbreaks caused by atypical mycobacteria are considered as an emerging problem in Brazil and Goias, being frequently associated with invasive procedures, such as laparoscopy, arthroscopy, and aesthetic surgeries among others. Treatment of mycobacteriosis requires highly toxic drugs with doubtful sterilizing effects. Consequently, several studies aim to search for new drugs or molecules with anti-mycobacterial biological activities. The objective of this study was to prospect biomolecules from the venom of the social wasp Polybia paulista (Vespoidea, Vespidae, Polistinae) and from the Tityus sp scorpion with antimycobacteria activity against Mycobacterium abscessus subsp. bolletii (GO06). Peptides from the wasp and scorpion venoms were evaluated in broth microdilution assay and in macrophage infected cultures to determine minimum inhibitory concentration. Peptides with antimycobacterial activity were further evaluated by scanning electron microscopy of M. abscessus subsp. bolletii treated cultures. The peptide toxicities were evaluated on macrophage cultures. Peptides Agelaia-MP, Polybia-MPII, and AVA, derived from wasp and peptides AMP 1, 2, 4, 6, and 8 derived from scorpion presented antimycobacterial activities. AVA and AMP 4 peptides were not toxic for macrophages. In this work three peptides derived from the wasp venom and five peptides derived from the scorpion venom were identified as having antimycobacterial activity. / Surtos causados por micobactérias atípicas são considerados emergentes no Brasil e em Goiás e têm tem sido associados a procedimentos invasivos, como a laparoscopia, artroscopia e cirurgia estética dentre outros. O tratamento de micobacterioses envolve drogas altamente tóxicas que apresentam efeito esterilizante relativo. Portanto, vários estudos têm como alvo a busca de novas drogas ou moléculas biológicas com atividade micobactericida. O objetivo deste estudo foi prospectar biomoléculas do veneno de vespa social Polybia paulista (Vespoidea, Vespidae, Polistinae) e de escorpiões do gênero Tityus com atividade micobactericida in vitro contra Mycobacterium abscessus subsp. bolletii (GO06). Peptídeos derivados do veneno da vespa e do escorpião foram avaliados por microdiluição em caldo, e em culturas de macrófagos infectados determinando a concentração inibitória mínima. Para os peptídeos com atividade micobactericida, o potencial dano causado à parede celular da micobactéria foi analisado por microscopia eletrônica de varredura. A toxicidade de dois peptídeos com potencial uso farmacológico foram avaliados em culturas de macrófagos peritoneais de camundongos BALB/c. Os peptídeos Agelaia-MP, Polybia-MPII e AVA derivados do veneno da vespa e os peptídeos AMP 1, 2, 4, 6 e 8 derivados do veneno de escorpião apresentaram atividade micobactericida. Os peptídeos micobactericidas agem desestruturando os envoltório das bacilos de M. abscessos subsp. bolletti. Os peptídeos AVA e o AMP 4 não apresentaram toxicidade para culturas de macrófagos, e reduziram a carga bacilar de culturas de macrófagos infectadas com M. abscessus subsp. bolletii. Neste trabalho identificou-se três peptídeos derivados da peçonha de vespa e cinco peptídeos derivados de veneno de escorpião com atividade micobactericida.

A tuberculose (TB) é uma doença infecciosa causada por bactérias do gênero Mycobacterium que acomete principalmente o sistema respiratório. A cepa Beijing 1471 (M. tuberculosis) induz uma resposta altamente pró-inflamatória, enquanto que a cepa MP287/03 (M. bovis) induz uma fraca resposta inflamatória. O receptor P2X7 (P2X7R) é um sensor de ATP extracelular, uma molécula associada ao dano que é liberada a partir de células necróticas. A TB induzida por ambas as cepas hipervirulentas Beijing 1471 e MP287/03 é atenuada em camundongos deficientes do P2X7R. Portanto o objetivo do nosso trabalho foi avaliar o papel do P2X7R na resposta imune da TB induzida por essas cepas hipervirulentas. Nós percebemos que apesar das diferenças na capacidade imunomodulatória induzida pelas cepas Beijing 1471 e MP287/03, o P2X7R exerce um papel importante na severidade da doença induzida por ambas as cepas, e que a ausência desse receptor foi capaz de restabelecer a resposta imune pulmonar a perfis semelhantes ao induzido pela cepa de menor virulência H37Rv de M. tuberculosis. / Tuberculosis (TB) is infectious diseases caused by Mycobacterium tuberculosis (Mtb) that mainly affect the respiratory system. Beijing 1471 strain (Mtb) induce a strong pro-inflammatory response, while MP287/03 strain (M. bovis) induce a weak pro-inflammatory response. The P2X7 receptor (P2X7R) is a sensor of extracellular ATP, a damage-associated molecule that is released from necrotic cells and that induces pro-inflammatory cytokine. TB caused by both hypervirulent strains Beijing 1471 and MP287/03 is attenuated in P2X7R deficient mice (P2X7RKO). Therefore, our aim was to investigate the role of P2X7R in imune response of TB induced by MP287/03 and Beijing 1471 strains. We has note that despite Beijing 1471 and MP287/03 strains have opposite immunomodulatory properties, the P2X7R have an important role in modulating the immune response induced by both strains. Thus, the lung immune responses induced by both hypervirulent infections in the absence of this receptor were similar to that induced by less virulent H37Rv Mtb mycobacteria.

Bien que présentes dans tous les écosystèmes lacustres, la composition ainsi que l'abondance des communautés bactériennes peut varier à l'échelle régionale mais également à l'échelle locale. Une meilleure compréhension des facteurs responsables de ces patrons biogéographiques permettrait d'améliorer la connaissance des fonctionnements de ces systèmes aquatiques et donc de leur réponse potentielle face aux pressions anthropiques. Dans ce contexte, cette thèse a visé à étudier la biogéographie du compartiment bactérien dans un ensemble de lacs peu profonds. Les objectifs principaux de cette étude ont été d'évaluer aux échelles régionale et locale les facteurs responsables des patrons biogéographiques pour (i) l'ensemble de la communauté bactérienne et (ii) pour un groupe bactérien spécifique, i.e. les mycobactéries non-tuberculeuses. Pour atteindre ces objectifs deux approches complémentaires ont été entreprises. Tout d'abord, la variabilité spatiale à l'échelle régionale a été évaluée par l'échantillonnage en Ile-de-France de 49 lacs pendant trois étés. Couplé à cette approche, une étude plus fine a été entreprise pour caractériser la dynamique spatiotemporelle du compartiment bactérien par le suivi mensuel pendant deux ans et de six évènements pluvieux importants au sein du lac de Créteil (Val de Marne).À l'échelle régionale, la variabilité spatiale de la structure de la communauté bactérienne pour les trois années de suivi (caractérisé par T-RFLP) a été prédite à hauteur de 76% (r carré moyen) par les processus stochastiques et moins de 14% par les facteurs déterministes incluant les paramètres environnementaux (statut trophique) et les processus de dispersion (connexion du lac à une rivière et les axes PCNM). L'analyse de la composition de la communauté bactérienne par séquençage à haut débit (MiSeq Illumina) a mis en évidence des résultats similaires à ceux acquis par T-RFLP. Cependant, cette analyse a révélé que l'importance des processus impliqués dans les patrons biogéographiques pouvait évoluer en fonction des phylums ou des classes bactériens considérés. La variabilité spatiale des densités de mycobactéries (PCR en temps réel), était quant à elle expliquée à hauteur de 50% par des facteurs déterministes (pH de l'eau, concentration en fer labile et connexion à une rivière).À l'échelle locale, le suivi du lac de Créteil n'a révélé aucune variation spatiale significative (le long des transects horizontal et vertical) de la structure de la communauté bactérienne ainsi que des densités de mycobactéries. Par contre une étude spécifique sur deux lacs a révélé des variations significatives de densité et la diversité des mycobactéries au sein de différents compartiments des lacs. À l'inverse, d'importantes variations temporelles de la structure des communautés bactériennes ont été observées au cours des deux années de suivi, principalement associées aux variations de température de l'eau. Par ailleurs, bien que relativement stable au cours des deux années de suivi, les variations de densités des mycobactéries ont seulement été prédites par les processus stochastiques à hauteur de 35% / Although bacteria are widespread in lacustrine environments, their composition and abundance vary at the regional and also at the local scale. A better understanding of the factors responsible for these biogeographic patterns would improve our knowledge of these aquatic systems and thus their potential response to anthropogenic pressures. In this context, this thesis studied the biogeography of the bacterial compartment in a set of shallow lakes located in the Paris area. The main objectives of this study were to assess at the regional and local scale the factors responsible for the biogeographical patterns on (i) the entire bacterial community, and (ii) a specific bacterial group, i.e. the nontuberculous mycobacteria. To achieve these objectives two complementary approaches were undertaken. First, at the regional scale, the spatial variability was assessed by sampling 49 lakes during three consecutive summers. A finer study was also performed to characterize the spatiotemporal dynamics of the bacterial compartment over a two-year monthly monitoring and during six important rain events within the Créteil Lake (Val de Marne).At the regional scale, the spatial variability of the bacterial community structure for the three summers (assessed by T-RFLP) was predicted for 76% (mean r-squared) by stochastic processes and less than 14% by deterministic factors including environmental parameters (trophic status) and dispersal-related process (connection to a river and PCNM axes). The analysis of the bacterial composition by high-throughput sequencing (Illumina MiSeq) showed similar tendencies to those acquired by T-RFLP. However, this analysis revealed that the importance of the processes involved in biogeographical patterns could vary according to the bacterial phyla or classes considered. Spatial variability of mycobacterial densities (real time PCR) was explained up to 50% by deterministic factors (water pH, amount of labile iron and connection to a river).At the local scale, the monitoring of Creteil Lake revealed no significant spatial variation (along the horizontal and vertical transect) on the structure of the bacterial community and mycobacterial densities. However, a specific study of two lakes showed that mycobacterial density and diversity significantly varied among the different compartments of the lakes. Inversely, significant temporal variations on the bacterial community structure were observed over the two-year of monitoring, mainly related to water temperature changes. Although mycobacterial densities were relatively stable over the Créteil Lake monitoring, their variations were only predicted by stochastic processes up to 35%

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Charles University, Faculty of Pharmacy, Hradec Králové Field of study: Specialist in laboratory methods Author: Bc. Tomáš Hampl Supervisor: PharmDr. Ondřej Janďourek, Ph.D. Title of diploma thesis: Mycobacterium tuberculosis as causative agent of grave illness The aim of this diploma thesis is to deal with tuberculosis, describe the pathogen, taxonomic classification, describe the origin, course and clinical manifestations of the disease, diagnosis, including laboratory diagnostics, epidemiology of tuberculosis, treatment and prevention. Tuberculosis (TBC) is one of the deadliest infectious diseases in the world caused by bacterium M. tuberculosis in humans. TBC is sometimes referred as a disease of the past, but the recent rise in cases of the disease, and especially the spread of forms of drug-resistant TBC, makes the disease very dangerous. Currently, a major problem is the alarming rise in resistant and multi-resistant tuberculosis, which is not counteracted by commonly used first-line drugs. Therefore, there is a constant emphasis around the world on discovering and testing new potential antituberculotics that could help patients with resistant and multidrug-resistant TBC. In the experimental part, the thesis deals with screening of antimycobacterial activity of potential antituberculotics...

IFNγ is an essential and pleiotropic activator of monocytes, but little is known about the effects IFNγ on cellular metabolism. Therefore, we sought to characterize and elucidate the mechanisms by which IFNγ reprograms monocyte metabolism to support its immunologic activities. First, we identified a critical role for IFNγ in the induction of immunoresponsive gene 1 (IRG1) and its product, itaconate. The immunometabolite, itaconate, has been reported to have antibacterial, anti-inflammatory and antioxidant activity. Irg1-/- mice, lacking itaconate, are highly susceptible and phenotypically similar to IFNγ knock out (GKO) mice upon infection with Mycobacterium tuberculosis. Therefore, we assessed the role of IRG1/itaconate in the context of non-tuberculous mycobacterial (NTM) infection, the most common type of infection in patients with immunodeficiencies caused by defects in IFNγ signaling. Our data suggest that impaired induction of itaconate in the context of mycobacterial infection may contribute to mycobacterial susceptibility and immune dysregulation in patients with defects in IFNγ signaling. Next, we evaluated the metabolic phenotype of IFNγ-stimulated human monocytes and found that IFNγ increased oxygen consumption rates (OCR), indicative of reactive oxygen species generation by both mitochondria and NADPH oxidase. Transcriptional profiling of human macrophages revealed that this oxidative phenotype was dependent on IFNγ-induced, nicotinamide phosphoribosyltransferase (NAMPT)-mediated NAD+ salvage to generate NADH and NADPH for oxidation by mitochondrial complex I and NADPH oxidase, respectively. These data identify an IFNγ-induced, NAMPT-dependent, NAD+ salvage pathway that is critical for complete induction of the respiratory burst in IFNγ stimulated human monocytes.

Mycobacterium tuberculosis (Mtb) is one of the most virulent and prevalent bacterial pathogens across the world. As Mtb infects millions of people a year, it remains essential to study its physiology with the goal of developing new therapeutic interventions. A critical part of the bacteria’s ability to propagate is through successful cell division. Although the process of bacterial cell division and the key proteins therein are well understood in Escherichia coli, much remains to be understood about division in mycobacteria. Genetic and cell biological approaches have recently begun to identify key divisome components in Mycobacterium smegmatis. However, questions remain regarding the role and function of one divisome protein in particular, the DNA translocase FtsK. In this dissertation, I investigated the necessity of FtsK for the growth of mycobacteria. Using an inducible knockdown of FtsK, I present evidence that complete loss of FtsK is required to inhibit growth in both Mtb and M. smegmatis, and that these orthologs share a homologous function. Additional work suggests extended loss of FtsK may be lethal to bacteria. These observations support that FtsK is an essential member of the divisome in mycobacteria, facilitating the processes of growth and division.

Charles University Faculty of Pharmacy in Hradec Kralove Department of Biological and Medical Sciences Study program: Specialist on Laboratory Methods Author: Bc. Tereza Pchálková Supervisor: PharmDr. Ondřej Janďourek, Ph.D. Title of diploma thesis: In vitro screening of potential antimycobacterial compounds active against fast growing strains of Mycobacterium genus II Key words: Mycobacteria, Tuberculosis, Antituberculotics, Microdilution broth method, Minimum inhibition concentration Background: The aim of this diploma thesis has been screening of in vitro antimycobacterial activity of novel compounds against fast growing strains of the genus Mycobacterium (Mycobacterium smegmatis and Mycobacterium aurum). Another aim has been predicting the structure-activity relationships for tested compounds. Methods: The technique used for activity determination was microdilution broth method. The value of minimum inhibition concentration for each compound was determined. The evaluation was performed visually and spectrophotometrically using the Alamar blue indicator. Results: A total of 79 compounds were tested. 22 tested compounds showed significant activity against mycobacteria. The substances were sorted according to the similarity in chemical structure into 10 groups. From a chemical point of view, these...