Os transportadores da família ABC são proteínas transmembrânicas envolvidas com o tráfego de substâncias endógenas e exógenas do meio intracelular para o extracelular, sendo alvos de estudo na resistência celular a agentes quimioterápicos. O ABCC2 é um transportador transmembrânico que exporta ativamente fármacos aniônicos conjugados e facilita o transporte de agentes anticâncer. O ABCG2 é outro transportador transmembrânico que tem influência na farmacocinética e farmacodinâmica de certos xenobióticos e substratos endógenos; além disso, acredita-se que este gene contribui para a resistência a várias drogas. Por esses motivos identificamos por sequenciamento ou PCR-RFLP os polimorfismos dos genes ABCC2 (Val417Ile, Ser789Phe e Ala1450Thr) e ABCG2 (Val12Met, Gly126stop códon, Gly141Lys) em 90 pacientes portadores de carcinoma epidermóide de cabeça e pescoço (HNSCC) e tentamos correlacionar a presença do polimorfismo com resposta a tratamento que incluiu cisplatina em todos os pacientes. Não encontramos nenhuma correlação entre a presença de polimorfismo para Val12Met, Gly141Lys e Val417Ile, determinados em 68 pacientes tratados exclusivamente com cisplatina e radioterapia, e a resposta ao tratamento. As curvas de sobrevida, determinadas por Kaplan-Meier, considerando polimórfico os pacientes que continham pelo menos um dos alelos alterados e selvagem os que não tivessem nenhum deles, mostraram que os pacientes selvagens para o polimorfismo Val12Met tiveram tendência a uma pior sobrevida (sobrevida mediana de 18,7 meses) em relação aos pacientes polimórficos (sobrevida mediana não atingida; P=0,089 Teste de log-rank), já os pacientes selvagens para o polimorfismo Gly141Lys tiveram tendência a uma pior sobrevida (sobrevida mediana de 15,8 meses) em relação aos pacientes polimórficos (sobrevida mediana de 25,6 meses; P = 0,16 Teste de logrank). Não observamos correlação entre os outros polimorfismos e sobrevida. Quanto ao GLY126stop, somente um paciente foi identificado como polimórfico. Conclusões: No nosso estudo, a freqüência do polimorfismo Val12Met de 10% está próxima dos 18% descrito na população normal (Kobayashi 2004). Nosso trabalho foi o primeiro a correlacionar estes polimorfismos com resposta ao tratamento em pacientes com carcinoma epidermóide de cabeça e pescoço e indica que Val12Met e Gly141Lys e o gene ABCG2 como um todo são candidatos a um estudo maior / ATP binding cassette (ABC) transporters form one of the largest transmembrane protein families. These proteins use cellular ATP to drive the transport of various substrates across cell membranes including many exogenous and endogenous compounds, which includes drugs used in cancer treatment. ABCC2 is an ATP binding cassette transporter which accepts a diverse range of substrates, including glutathione, glucuronide, and sulfate conjugates of many metabolites and xenobiotics. ABCG2 is a member of the ATP binding cassette (ABC) transporters whose function is to pump out of the cell a wide variety of endogenous and exogenous compounds. Widely expressed in stem cells, ABCG2 is also recognized as a universal marker of stem cells. For these reasons we had identified the following polymorphisms of ABCC2 gene: -Val417Ile, Ser789Phe and Ala1450Thr- and of ABCG2 gene as well: -Val12Met, Gly126stop códon, Gly141Lys in 88 patients with head and neck squamous cell carcinoma (HNSCC). Methodology included PCR - RFLP and direct sequencing. Survival analysis was done using Kaplan-Meier curves and response measured by RECIST criteria. Comparisons were done between polymorphic patients in which at least one polymorphism was present as opposed to the patients without the polymorphism. Correlation with response to treatment was studied for Val12Met, Gly141Lys e Val417Il in 68 patients exclusively treated with concomitant cisplatin and radiotherapy and no correlation was found between these markers and treatment response. Patients without the Val12Met presented a trend towards shorter survival (median survival 18.7 months) as compared to polymorphic patients (median survival not reached, long rank p= 0.089). Although statistical significance was not reached, patients wild type for Gly141Lys polymorphism (median survival 15.8 months) had shorter survival than polymorphic patients (25.6 months, p=0.16). We did not observe any other correlation between other polymorphisms and survival. With respect to Gly126stop, only one patient was identified as polymorphic and survival analysis was not possible. As far as we know this is the first study to try to correlate these polymorphisms with treatment response and survival in HNSCC patients. Although we were unable to draw any definitive conclusions, our results indicate that Val12Met and Gly141Lys deserve to be further studied in the future.

No description available.

Apesar de amplamente estudados, os mecanismos envolvidos no processo de transformação neoplásica das células hipofisárias e na progressão desses tumores permanecem, ainda, pouco esclarecidos. Os genes da kisspeptina (KISS1), originalmente identificado como um supressor tumoral, e de seu receptor (KISS1R) desempenham um papel crucial no eixo hipotalâmico-hipofisário-gonadal e sua perda de expressão foi, recentemente, relacionada ao surgimento dos adenomas hipofisários. Com o objetivo de estudar a importância do KISS1/KISSR nesses tumores, foram avaliadas a expressão desses genes e a frequência do polimorfismo rs5780218 na região promotora do KISS1, em somatotropinomas e adenomas hipofisários clinicamente não funcionantes (ACNF). Foram avaliados 97pacientes, 49 somatotropinomas e 48 ACNF. DNA tumoral foi obtido de todos os tumores e RNA de 68 caso. Desses tumores, 52 foram classificados como invasivos (44 apresentavam invasão apenas para o seio cavernoso) e 45 não invasivos. A quantificação da expressão do mRNA de KISS1 e KISS1R foi realizada pela qPCR em tempo real com sondas TaqMan utilizando o método de quantificação relativa 2-deltaCt. A determinação do genótipo do rs5780218 foi feita por PCR seguida pela técnica de polimorfismo no comprimento do fragmento de restrição (RFLP). O gene KISS1 apresentou-se hipo-expresso na vasta maioria dos pacientes avaliados (97.2% dos somatotropinomas e 92.6% do ACNF). Em relação ao KISS1R, este também estava hipo-expresso na maior parte dos pacientes (100% dos somatotropinomas e 84.4% dos ACNF). Hiperexpressão do KISS1 e KISS1R foi rara em ambos os subtipos tumorais. Em relação as características clínicas dos pacientes e ao fenótipo tumoral, como tamanho e invasividade, não foram encontradas diferenças significantes na expressão desses genes. A avaliação do polimorfismo rs5780218 no KISS1 mostrou que o genótipo homozigoto para o alelo variante foi bem mais frequente nos somatotropinomas (32.6%) versus ACNF (10.4%; P=0.03). A presença do rs5780218 foi relacionada a invasividade tumoral, quando considerado apenas a invasão para o seio cavernoso (P=0.03). Esse é um dado interessante, já que a KISS1 pode formar um complexo com as metaloproteinases e estas têm sido relacionadas a invasão dos adenomas hipofisários para o seio cavernoso e não para o seio esfenoidal. Entre os pacientes com ACNF, o alelo variante foi mais frequente nos indivíduos do sexo masculino (P=0.02) e foi relacionado com uma menor idade de diagnóstico (mediana 33.0 anos, min 26 - max 42) quanto presente em homozigose (P < 0.01); os pacientes homozigotos para o alelo ancestral e heterozigotos apresentaram idade diagnóstica com mediana de 50.0 (min 19 - max 73) e 54.8 (min 17- max 84), respectivamente. Curiosamente, a expressão do KISS1 foi menor nos tumores com homozigose para o alelo mutante tantos nos somatotropinomas quanto nos ACNF. Em conclusão, foi observada hipo-expressão do KISS1 e KISS1R nos somatotropinomas e ACNF, podendo essa perda expressão estar relacionada a gênese desses adenomas. O alelo variante rs5780218 KISS1 foi relacionado a invasão para o seio cavernoso e encontrado em maior frequência nos somatotropinomas, sugerindo que a importância dos KISS1/KISS1R pode diferir entre os subtipos de tumores hipofisários / Although broadly studied, the mechanisms involved in the neoplastic process of pituitary cells remains still unclear. Kisspeptin1 (KISS1), originally identified as a tumor suppressor, and its receptor (KISS1R) play a crucial role in the hypothalamic-pituitary-gonadal axis and the loss of their expression was, recently, associated with pituitary adenomas onset. Aiming to investigated the importance of KISS1/KISS1R in these tumors, expression of KISS1 and KISS1R was determined in somatotropinomas and nonfunctioning pituitary adenomas (NFPA). The frequency of the rs5780218 polymorphism, located in the KISS1 promoter region, was also evaluated. A total of 97 patients were assessed, 49 somatotropinomas and 48 NFPA. Among these, 52 were categorized as invasive (44 of which only showed invasion to the cavernous sinus). KISS1 and KISS1R mRNA expression was performed through RT-qPCR using TaqMan probes and the 2-deltaCt relative quantification method. KISS1 rs5780218 genotyping was done by PCR and restriction fragment length polymorphism (RFLP) method. The KISS1 gene was underexpressed in the vast majority of the cases (97.2% of the somatotropinomas and 92.6% of NFPA). KISS1Runderexpression have also been observed in most cases (100% of the somatotropinomas and 84.4% of the NFPA). KISS1 and KISS1R overexpression was rarely detected. No significant differences were found between KISS1 and KISS1R gene expression and patient\'s clinical characteristics and tumor phenotype, such as size and invasiveness. The characterization of rs5780218 showed that the variant genotype in homozygosis was much more frequent in somatotropinomas (32.6%) versus NFPA (10.4%; P=0.03). The presence of variant allele was associated with tumor invasiveness when considered invasion to the cavernous sinus only (P=0.03). This data is particularly interesting, since KISS1 has the ability for form a complex with metalloproteinases and these, for instance, are related to invasiveness of pituitary adenomas to the cavernous, but not to the sphenoidal, sinus. When considered only NFPA, the variant allele was more frequent in males (P=0.02) and was associated with earlier age at presentation (median 33 years old, min 26 - max 42) when in homozygosis (P < 0.01); the wilt-type homozygotes and heterozygotes had medians of 50.0 (min 19 - max 73) and 54.8 (min 17 - max 84), respectively. Curiously, KISS1 expression was lower in rs5780218 homozygotes both in somatotropinomas and NFPA. In conclusion, we have identified the KISS1 and KISS1R underexpression in both somatotropinomas and NFPA, which lead to notion that the loss of expression might be related to the genesis of these adenomas. The rs5780218 KISS1 variant allele was associated with invasion to the cavernous sinus and was found to be more frequent in somatotropinomas, suggesting that role of KISS1/KISS1R in tumor behavior might differ between pituitary adenomas subtypes

Made available in DSpace on 2016-04-27T17:27:13Z (GMT). No. of bitstreams: 1 Rodrigo Inacio Ribeiro de Sa Menezes.pdf: 3732162 bytes, checksum: fc87dc189899e8b6019c55d04394ad74 (MD5) Previous issue date: 2016-03-07 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Cioran (1911-1995) is a Romanian-French thinker who would not have the right to complain about being misunderstood or even ignored, inasmuch as he begged to turn marginality into a philosophical imperative and a lifestyle. Eleven years since his death, in Paris, and one hundred since his birth, in Transylvania, this one author, the perfect stranger in more than one sense, remains largely unknown by the Brazilian audience, scholarly or not, in such a way that his shady aura, so to speak, as well as countless legends and rumors prevail about his life, personality and thought. Having said that, and apart from his own will to marginality, Cioran is a thinker who just can t and will not remain as such for much longer ignored or spurned, be it by Academia as such or by particular intellectual milieus with varied ideological outlooks. All the more when it comes to reflect upon problems which happen to be just as prevailing as worrying, such as the rise of integralism and of fanaticism, be it religious or of any other kind, atheism, skepticism and nihilism in the XXth century, anguish, despair, the metaphysical need of mankind and the sense of ultimate transcendence, suffering, death, suicide, evil, finally, a wide range of questions which are all highly relevant from a philosophical standpoint and also that of human sciences. In the first part of this inquiry, we aim at showing that philosophical pessimism and apophatic dwell mix up in the existential metaphysics of Cioran, a religious philosophy of existence which, not being guided up by the faith in revealed truths and by the adhesion to external authorities, aims to think human existence and condition according to that which is most imperious and essential, in Cioran s view, when it comes to the metaphysical animal: wisdom rather than science, deliverance by disillusion rather than salvation by faith and knowledge, the need for the absolute to the detriment of the delusions of becoming, coping with the contingency inherent to existence, namely human existence, tragically gifted with reflexive consciousness, freedom, a destiny. Cioran s organically existential thought is inseparable from, as he puts it, from his own life experience, namely the insomnia to which he accredits the merit or the fault for his blessed, for his cursed lucidity: a state of mind incompatible with life, turning life into a state of non-suicide . If there is pessimism, skepticism, nihilism, mysticism within the sum of attitudes that composes the works of Cioran, such attitudes which might as well be modalized as reactions to the problem of evil, all these tendencies emanate from insomnia-bred lucidity. Secondly, we shall turn our attention to the topic of Cioran s écriture, with everything it implies, differently than his Romanian writing, as far as style, concern for expression and the aestheticizing of discourse are concerned. We aim at showing that the Farewell to philosophy enounced by the author in A short history of decay (Précis de decomposition), parallel to his literary turn and the radicalization of the fragmentary principle that precedes his French writing, is the paradoxical expression of a negation-driven thought which, by betraying Philosophy with Poetry, Music and Mysticism, cannot help but pay an unheard-of tribute to Human thought and to Philosophy itself. Finally, we argue that Cioran s French works represent, by its form and content, the necessary consequence and exact expression of a lucid, organic thought, which discovers in the écriture de soi the very destiny of Western Philosophy, and in Style as adventure the highest form of modern-thought heroism / Cioran (1911-1995) é um pensador romeno-francês que não teria o direito de reclamar por ser incompreendido e ignorado, pois ele mesmo fez da marginalidade um imperativo filosófico e um estilo de vida. Onze anos após o seu falecimento, em Paris, e cem anos após o seu nascimento, na Transilvânia, este autor, estrangeiro em mais de um sentido, permanece em grande medida desconhecido pelo público brasileiro, acadêmico ou não, fazendo prevalecer sua aura de obscuro e um sem-número de lendas e rumores sobre a sua vida, a sua personalidade, o seu pensamento. Dito isso, e vontade de marginalidade à parte, Cioran é um pensador que não pode ser e não permanecerá sendo por muito tempo ignorado ou desprezado, seja pela Academia como pelos círculos intelectuais com as mais diversas orientações ideológicas. Ainda mais quando se trata de pensar problemáticas, tão atuais quanto preocupantes, como a ascensão do fundamentalismo e do fanatismo, religioso ou de outra natureza, o ateísmo, o ceticismo e o niilismo no século XX, a angústia, o desespero, a necessidade metafísica do homem e o sentido da transcendência, o sofrimento, a morte, o suicídio, o mal, enfim, uma gama de questões altamente relevantes do ponto de vista da filosofia e também de outras disciplinas, como a psicologia e a história. Na primeira parte desta investigação, pessimismo filosófico e misticismo apofático convivem na metafísica existencial de Cioran, uma filosofia religiosa da existência que, sem se pautar pela fé em verdades relevadas e pela adesão a autoridades externas, busca pensar a condição e a existência humanas de acordo com aquilo que é mais urgente e essencial no animal metafísico, segundo o autor: a sabedoria antes que a ciência, a libertação pela desilusão e pelo não-saber antes que a salvação pela crença e pelo conhecimento, a necessidade de absoluto em detrimento da ilusão do devir, o enfrentamento da contingência inerente à existência, e particularmente à existência humana, tragicamente dotada de uma consciência, de uma liberdade, de um destino. O pensamento orgânico de Cioran é inseparável, como ele o reitera, de sua experiência de vida, notadamente a insônia à qual ele atribuiria, posteriormente, o mérito ou a culpa da sua bendita, maldita lucidez: um estado de espírito incompatível com a vida, tornando-a um estado de não-suicídio . Se há pessimismo, ceticismo, niilismo e misticismo na soma de atitudes que é a obra de Cioran, atitudes que podem ser justamente modalizadas como atitudes frente ao problema do mal, todas essas tendências emanam da lucidez gestada a partir de suas noites em branco. Em um segundo momento, nos voltaremos à questão da écriture cioraniana, com tudo o que ela implica, diferentemente da escrita romena, em termos de estilo, preocupação com a forma e estetização do discurso. Pretendemos mostrar como o Adeus à filosofia declarado por Cioran no Breviário de decomposição, concomitantemente à guinada literária e à acentuação do princípio fragmentário que precede sua obra francesa, é a expressão paradoxal de um pensamento da negação que, traindo a filosofia com a poesia, a música e a mística, não deixa de prestar uma homenagem inaudita ao pensamento e à própria Filosofia, doravante irreconhecível. Por fim, argumentamos que a obra francesa de Cioran representa, em forma e conteúdo, a consequência necessária e a expressão exata de um pensamento lúcido e orgânico que descobre na escritura de si o destino da filosofia e no estilo como aventura o grande heroísmo do escritor moderno. Em Cioran, Filosofia e Literatura se juntam numa fuga para dentro do niilismo, como forma de resistir às tentações do nada

Les anticorps catalytiques (ou abzyme) ont fait l’objet de nombreuses recherches et ont été produits pour réaliser de nombreuses réactions. Ces protéines ont été ensuite découvertes dans le sérum d’individus sains ou atteints de pathologies, dont les pathologies autoimmunes. Les études suggèrent que ces abzymes peuvent avoir des effets bénéfiques ou délétères sur la santé des individus. L’origine des anticorps catalytiques et leur rôle restent ambigus et doivent être approfondis. Nous avons développé une nouvelle stratégie visant à étudier les abzymes, basée sur la technologie du phage display. Nous avons construit 4 banques de fragments d’anticorps, chacune présentant un répertoire immun différent (fond génétique et état d’immunitaire) : saine et naïve, saine et immunisée, autoimmune et naïve, et autoimmune et immunisée. Les stratégies d’amplification et de clonage des régions variables des immunoglobulines ont été conçues afin d’optimiser la taille et la diversité des banques. Nous avons rassemblé les 4 banques en une banque unique élargie contenant 2.7×109 séquences. L’analyse des séquences a mis en évidence des différences dans les profils d’expression des sous-groupes de gènes selon la banque. Nous avons ensuite procédé à la sélection d’abzymes à activité β-lactamase en utilisant deux cibles : un peptide cyclique, et un dérivé de sulfone pénam, inhibiteurs de l’enzyme. Nous avons sélectionné 5 abzymes. Chacun de ces immunoglobulines ont des séquences protéiques propres, incluant un potentiel site actif. Ces résultats montrent que différents motifs peuvent assurer la fonction catalytique de la β-lactamase, confirmant la flexibilité moléculaire de cette enzyme. / Catalytic antibodies (or abzymes) have been the focus numerous studies for some decades and have been produced with the ability to catalyze a wide range of reactions. They have also been discovered naturally in normal physiological and pathological conditions, notably on the background of autoimmune disease. Some have beneficial effects and others are detrimental to individual’s health. Hence, the origin of abzymes and their role in the immune response are ambiguous and must be enhanced. We have developed a novel strategy for the study of abzymes based on the phage display technology. We have constructed 4 libraries representing 4 murine immune repertoires with different genetic backgrounds and immunological states : healthy and naïve, healthy and immunized, autoimmune and naïve , and autoimmune and immunized. The strategies for the amplification and cloning of the immunoglobulin (lg) variable regions have been designed to optimize the size and diversity of the libraries. We have been able to pool the four libraries to create a large repertoire of size 2.7x109. After sequence analysis, we have found a number of statistically significant differences between the libraries. We have then used two strategically chosen targets to select for antibodies endowed with β lactamase activity : a cycle peptide and a penam sulfone, both inhibitors of the enzyme. We have selected for a total of 5 lgs endowed with β lactamase activity. The selected abzymes have different amino acid sequences. 3D modeling has provides insights on potential active sites demonstrating the ability of different structures to maintain the β lactamase activity and confirming the flexibility of the active site.

Os transportadores da família ABC são proteínas transmembrânicas envolvidas com o tráfego de substâncias endógenas e exógenas do meio intracelular para o extracelular, sendo alvos de estudo na resistência celular a agentes quimioterápicos. O ABCC2 é um transportador transmembrânico que exporta ativamente fármacos aniônicos conjugados e facilita o transporte de agentes anticâncer. O ABCG2 é outro transportador transmembrânico que tem influência na farmacocinética e farmacodinâmica de certos xenobióticos e substratos endógenos; além disso, acredita-se que este gene contribui para a resistência a várias drogas. Por esses motivos identificamos por sequenciamento ou PCR-RFLP os polimorfismos dos genes ABCC2 (Val417Ile, Ser789Phe e Ala1450Thr) e ABCG2 (Val12Met, Gly126stop códon, Gly141Lys) em 90 pacientes portadores de carcinoma epidermóide de cabeça e pescoço (HNSCC) e tentamos correlacionar a presença do polimorfismo com resposta a tratamento que incluiu cisplatina em todos os pacientes. Não encontramos nenhuma correlação entre a presença de polimorfismo para Val12Met, Gly141Lys e Val417Ile, determinados em 68 pacientes tratados exclusivamente com cisplatina e radioterapia, e a resposta ao tratamento. As curvas de sobrevida, determinadas por Kaplan-Meier, considerando polimórfico os pacientes que continham pelo menos um dos alelos alterados e selvagem os que não tivessem nenhum deles, mostraram que os pacientes selvagens para o polimorfismo Val12Met tiveram tendência a uma pior sobrevida (sobrevida mediana de 18,7 meses) em relação aos pacientes polimórficos (sobrevida mediana não atingida; P=0,089 Teste de log-rank), já os pacientes selvagens para o polimorfismo Gly141Lys tiveram tendência a uma pior sobrevida (sobrevida mediana de 15,8 meses) em relação aos pacientes polimórficos (sobrevida mediana de 25,6 meses; P = 0,16 Teste de logrank). Não observamos correlação entre os outros polimorfismos e sobrevida. Quanto ao GLY126stop, somente um paciente foi identificado como polimórfico. Conclusões: No nosso estudo, a freqüência do polimorfismo Val12Met de 10% está próxima dos 18% descrito na população normal (Kobayashi 2004). Nosso trabalho foi o primeiro a correlacionar estes polimorfismos com resposta ao tratamento em pacientes com carcinoma epidermóide de cabeça e pescoço e indica que Val12Met e Gly141Lys e o gene ABCG2 como um todo são candidatos a um estudo maior / ATP binding cassette (ABC) transporters form one of the largest transmembrane protein families. These proteins use cellular ATP to drive the transport of various substrates across cell membranes including many exogenous and endogenous compounds, which includes drugs used in cancer treatment. ABCC2 is an ATP binding cassette transporter which accepts a diverse range of substrates, including glutathione, glucuronide, and sulfate conjugates of many metabolites and xenobiotics. ABCG2 is a member of the ATP binding cassette (ABC) transporters whose function is to pump out of the cell a wide variety of endogenous and exogenous compounds. Widely expressed in stem cells, ABCG2 is also recognized as a universal marker of stem cells. For these reasons we had identified the following polymorphisms of ABCC2 gene: -Val417Ile, Ser789Phe and Ala1450Thr- and of ABCG2 gene as well: -Val12Met, Gly126stop códon, Gly141Lys in 88 patients with head and neck squamous cell carcinoma (HNSCC). Methodology included PCR - RFLP and direct sequencing. Survival analysis was done using Kaplan-Meier curves and response measured by RECIST criteria. Comparisons were done between polymorphic patients in which at least one polymorphism was present as opposed to the patients without the polymorphism. Correlation with response to treatment was studied for Val12Met, Gly141Lys e Val417Il in 68 patients exclusively treated with concomitant cisplatin and radiotherapy and no correlation was found between these markers and treatment response. Patients without the Val12Met presented a trend towards shorter survival (median survival 18.7 months) as compared to polymorphic patients (median survival not reached, long rank p= 0.089). Although statistical significance was not reached, patients wild type for Gly141Lys polymorphism (median survival 15.8 months) had shorter survival than polymorphic patients (25.6 months, p=0.16). We did not observe any other correlation between other polymorphisms and survival. With respect to Gly126stop, only one patient was identified as polymorphic and survival analysis was not possible. As far as we know this is the first study to try to correlate these polymorphisms with treatment response and survival in HNSCC patients. Although we were unable to draw any definitive conclusions, our results indicate that Val12Met and Gly141Lys deserve to be further studied in the future.

Work presented in this thesis is in two parts. Part one: The X-ray crystal structures of potential antimicrobial drug targets. The protein IspF (2C-methyl-D-erythritol-2,4-cyclodiphosphate synthase, EC: 4.6.1.12) from two pathogens (Burkholderia cenocepacia and Plasmodium falciparum) has been investigated. IspF is an enzyme of isoprenoid-precursor biosynthesis and is considered to be a potential drug target. The results of structural and fragment-screening efforts presented here inform early stage drug discovery efforts. The structure of the PabC protein (4-amino-4-deoxychorismate lyase, EC: 4.1.3.38) from the Gram-negative pathogen Pseudomonas aeruginosa was also determined. PabC is involved in the production of para-aminobenzoic acid on the path to folate. Comparisons with previously solved PabC structures identified a spatially conserved tyrosine residue in the active site and suggest that a re-evaluation of a published mechanism is warranted. Part two: Immunity proteins in the Gram-negative Type VI secretion system. The X-ray crystal structures of the proteins Rap1a and Rap2a from Serratia marcescens, inhibitors of the peptidoglycan amidase toxins secreted by some Gram-negative bacteria employing the Type VI secretion pathway, were determined by molecular replacement and analysed.

Protoplast fusion of Lolium perenne and Lotus corniculatus for gene introgression by Sanjeev V. Raikar Lolium perenne is one of the most important forage crops globally and in New Zealand. Lotus corniculatus is a dicotyledonous forage that contains valuable traits such as high levels of condensed tannins, increased digestibility, and high nitrogen fixing abilities. However, conventional breeding between these two forage crops is impossible due to their markedly different taxonomic origin. Protoplast fusion (somatic hybridisation) provides an opportunity for gene introgression between these two species. This thesis describes the somatic hybridisation, the regeneration and the molecular analysis of the putative somatic hybrid plants obtained between L. perenne and L. corniculatus. Callus and cell suspensions of different cultivars of L. perenne were established from immature embryos and plants were regenerated from the callus. Of the 10 cultivars screened, cultivars Bronsyn and Canon had the highest percentage of callus induction at 36% each on 5 mg/L 2,4-D. Removal of the palea and lemma which form the seed coat was found to increase callus induction ability of the embryos. Plant regeneration from the callus was achieved when the callus was plated on LS medium supplemented with plant growth regulators at different concentrations. Variable responses to shoot regeneration was observed between the different cultivars with the cv Kingston having the lowest frequency of shoot formation (12%). Different factors affecting the protoplast isolation of L. perenne were investigated. The highest protoplast yield of 10×106 g-1FW was obtained when cell suspensions were used as the tissue source, with enzyme combination ‘A’ (Cellulase Onozuka RS 2%, Macerozyme R-10 1%, Driselase 0.5%, Pectolyase 0.2%), for 6 h incubation period in 0.6 M mannitol. Development of microcolonies was only achieved when protoplasts were plated on nitrocellulose membrane with a L. perenne feeder layer on PEL medium. All the shoots regenerated from the protoplast-derived calli were albino shoots. The highest protoplast yield (7×106 g-1FW) of L. corniculatus was achieved from cotyledons also with enzyme combination ‘A’ (Cellulase Onozuka RS 2%, Macerozyme R-10 1%, Driselase 0.5%, Pectolyase 0.2%), for 6 h incubation period in 0.6 M mannitol. The highest plating efficiency for L. corniculatus of 1.57 % was achieved when protoplasts were plated on nitrocellulose membrane with a L. perenne feeder layer on PEL medium. The highest frequency of shoot regeneration (46%) was achieved when calli were plated on LS medium with NAA (0.1 mg/L) and BA (0.1 mg/L). Protoplast fusion between L. perenne and L. corniculatus was performed using the asymmetric somatic hybridisation technique using PEG as the fusogen. L. perenne protoplasts were treated with 0.1 mM IOA for 15 min and L. corniculatus protoplasts were treated with UV at 0.15 J/cm2 for 10 min. Various parameters affecting the fusion percentage were investigated. Successful fusions were obtained when the fusions were conducted on a plastic surface with 35% PEG (3350 MW) for 25 min duration, followed by 100 mM calcium chloride treatment for 25 min. A total of 14 putative fusion colonies were recovered. Shoots were regenerated from 8 fusion colonies. Unexpectedly, the regenerated putative hybrid plants resembled L. corniculatus plants. The flow cytometric profile of the putative somatic hybrids resembled that of L. corniculatus. Molecular analysis using SD-AFLP, SCARs and Lolium specific chloroplast microsatellite markers suggest that the putative somatic hybrids could be L. corniculatus escapes from the asymmetric protoplast fusion process. This thesis details a novel Whole Genome Amplification technique for plants using Strand Displacement Amplification technique.

While the study of complete sources is very valuable, and has contributed greatly to what is understood of music history, the perspective they contribute is limited because they cannot reveal information about how music and music sources were most often used. The study of functional sources, more probably created for use, allows for more insight into how music was performed and understood, and how such sources were created, used and valued. This study examines twelve fragmentary early sixteenth-century English sources from the Digital Image Archive of Medieval Music (DIAMM) database, constituting a sample of functional music sources in this period. The study of this sampling reveals information about how functional manuscripts were created, used and valued in England during this time period. Some of the fragments contain works with concordances. These concordances are compared using variant comparison, where differences in the versions of the work are considered and weighed. The comparative study of concordances provides insight into the transmission of the versions, scribal and performance culture, as well as into music culture in general. Overall, the study of this sampling of early sixteenth-century functional English sources provides a clearer understanding of the use of accidentals, scribes and scribal culture, performers, performance practice and music culture in England at this time, contributing to the understanding of music history.

While the study of complete sources is very valuable, and has contributed greatly to what is understood of music history, the perspective they contribute is limited because they cannot reveal information about how music and music sources were most often used. The study of functional sources, more probably created for use, allows for more insight into how music was performed and understood, and how such sources were created, used and valued. This study examines twelve fragmentary early sixteenth-century English sources from the Digital Image Archive of Medieval Music (DIAMM) database, constituting a sample of functional music sources in this period. The study of this sampling reveals information about how functional manuscripts were created, used and valued in England during this time period. Some of the fragments contain works with concordances. These concordances are compared using variant comparison, where differences in the versions of the work are considered and weighed. The comparative study of concordances provides insight into the transmission of the versions, scribal and performance culture, as well as into music culture in general. Overall, the study of this sampling of early sixteenth-century functional English sources provides a clearer understanding of the use of accidentals, scribes and scribal culture, performers, performance practice and music culture in England at this time, contributing to the understanding of music history.