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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Pharmacological investigations into matrix metalloproteinase-activated anti-tumour prodrugs. In vitro metabolic and pharmacological investigations into a series of colchicine-based peptide prodrugs activated by tumour-expressed matrix metalloproteinases

Youssef, Ahmed M.M. January 2014 (has links)
Matrix metalloproteinases (MMPs) play a significant role in degrading the extra- cellular matrix in cancer development and metastasis. Overexpression of matrix metalloproteinases in tumour tissues relative to normal tissues has been exploited as a target for peptide-based therapeutics, to improve therapeutic index of currently used agents. The stability of MMP-activated prodrugs in normal tissue or organs is a significant challenge for their success in the clinic. In an in vitro study, the stability of twenty six prodrugs was studied in mouse liver, kidney, lung and tumour homogenates using HPLC and LC/MS. Selected agents were studied in vivo. Each prodrug has a characteristic amino acid sequence with dominant FITC N-terminal end cap. All prodrugs were conjugated to a colchicine derivative (ICT 2552) which is a vascular disrupting agent causing tumour vasculature shutdown and consequently, tumour necrosis. ICT 3146, ICT 3019, ICT 3120 and ICT 3115 prodrugs showed significant stability in normal tissues and considerable activation in certain tumour tissues compared to the lead compound ICT 2588. Also, the selectivity of promising prodrugs to the MMP family was confirmed by using leupeptin (serine, cysteine and threonine protease inhibitor), pepstatin A (aspartate protease inhibitor), phosphoramidon (nepralysin inhibitor), ilomastat (metalloproteinase inhibitor) and BML-P115 (matrix metalloproteinase inhibitor). Moreover, members of the MMP family responsible for cleaving the selected prodrugs were identified using recombinant MMP enzymes. Furthermore, a LC/MS-MS method was developed to specifically detect and quantify MMP-16 protein expression in H460 tumour. MMP- 16 was responsible for the cleavage of ICT 3146 and ICT 3115. Therefore, MMP-activated prodrugs could be a useful therapeutic approach to avoid off-site toxicities of currently used anti-tumour agents. / The full text will be available at the end of the extended embargo: 5th March 2027
42

Synthesis and biological evaluation of MMP-activated anti-cancer prodrugs

Banisalman, Katreen A.F. January 2021 (has links)
The full text will be available at the end of the embargo period: 28th March 2027
43

Le transcriptome ABC dans la différenciation, la détoxication et la chimiorésistance.

Garrido, Edith 25 October 2007 (has links) (PDF)
Les transporteurs ABC constituent une famille de protéines membranaires qui assurent une fonction de transport, au travers des membranes cellulaires. Plusieurs ABC sont impliqués dans des physiopathologies humaines ou induisent des phénotypes de résistance. Ce manuscrit présente l'étude de l'expression de l'ensemble des ABC, par PCR quantitative, dans différents organes, ou en réponse à un traitement chez l'Homme et la souris. Nous avons étudié l'effet d'un traitement colchicine sur des lignées cellulaires humaines et des souris. Nous avons montré que ce traitement permettait d'induire l'expression de transporteurs ABC. Nous avons établi la première cartographie de l'expression des transporteurs ABC au cours du développement hépatique. Certains transporteurs absents du foie fœtal s'expriment après la naissance et jouent probablement un rôle dans la physiopathologie du foie adulte. A l'inverse l'expression de certains transporteurs s'éteint après la naissance, suggérant un rôle dans l'hématopoïèse. Nous avons mesuré l'expression des transporteurs ABC sur des biopsies de patients atteints de leucémies aiguës en corrélation avec leur sensibilité aux chimiothérapies. De façon intéressante, nous avons montré que des transporteurs jusqu'à présent non décrits dans la résistance pourraient contribuer à un mauvais pronostic. Enfin, nous avons étudié le transcritpome ABC dans les cellules souches humaines à différents stades de différenciation. Certains transporteurs pour lesquels nous observons des variations d'expression pourraient caractériser un état de différenciation et être impliqués dans l'auto-renouvellement ou la différentiation des cellules souches.
44

Approaches to Pharmacological Treatment and Gene Therapy of Cystic Fibrosis

Dragomir, Anca January 2004 (has links)
<p>Cystic fibrosis (CF) is the most common lethal genetic disease in the white population. It is due to mutations in the gene coding for the cystic fibrosis transmembrane conductance regulator (CFTR), a protein that functions mainly as a cAMP-activated chloride channel. The disease impairs ion and water transport in epithelia-lined organs such as airways, digestive tract, reproductive epithelium and sweat glands. At present the only therapy is symptomatic and development of curative treatment depends on uncovering the links between the defective CFTR and the disease, as well as on improving end-point measurements. </p><p>A method has been established for studying ion transport in an easily accessible cell type (nasal epithelial cells) from normal and cystic fibrosis patients by X-ray microanalysis. This method represents a rather simple and direct way of measuring simultaneously several chemical elements of biological interest.</p><p>Studies of chloride transport by means of a fluorescent indicator (MQAE) in nasal epithelial cells from CF patients showed that the phenotype cannot exclusively be explained by the CFTR activity in patients with severe genotype. </p><p>A common Portuguese CFTR mutation (A561E) causes protein mislocalization in the endoplasmic reticulum similar to the most common CF mutation (ΔF508) and thus it should be possible to treat it with the same pharmacological strategies.</p><p>Chronic treatment of CF airway epithelial cells with nanomolar concentrations of colchicine increased the chloride efflux via chloride channels other than CFTR, strengthening the notion that colchicine could be beneficial to CF patients.</p><p>Successful <i>in vitro </i>transfection of CF airway epithelial cells with cationic vectors was possible with short incubation times. Heparin added at the end of the transfection incubation time could help to maintain the viability of the cells, without interfering with the transfection efficiency. It seems possible that heparin could be an adjuvant for non-viral mediated gene therapy.</p>
45

Approaches to Pharmacological Treatment and Gene Therapy of Cystic Fibrosis

Dragomir, Anca January 2004 (has links)
Cystic fibrosis (CF) is the most common lethal genetic disease in the white population. It is due to mutations in the gene coding for the cystic fibrosis transmembrane conductance regulator (CFTR), a protein that functions mainly as a cAMP-activated chloride channel. The disease impairs ion and water transport in epithelia-lined organs such as airways, digestive tract, reproductive epithelium and sweat glands. At present the only therapy is symptomatic and development of curative treatment depends on uncovering the links between the defective CFTR and the disease, as well as on improving end-point measurements. A method has been established for studying ion transport in an easily accessible cell type (nasal epithelial cells) from normal and cystic fibrosis patients by X-ray microanalysis. This method represents a rather simple and direct way of measuring simultaneously several chemical elements of biological interest. Studies of chloride transport by means of a fluorescent indicator (MQAE) in nasal epithelial cells from CF patients showed that the phenotype cannot exclusively be explained by the CFTR activity in patients with severe genotype. A common Portuguese CFTR mutation (A561E) causes protein mislocalization in the endoplasmic reticulum similar to the most common CF mutation (ΔF508) and thus it should be possible to treat it with the same pharmacological strategies. Chronic treatment of CF airway epithelial cells with nanomolar concentrations of colchicine increased the chloride efflux via chloride channels other than CFTR, strengthening the notion that colchicine could be beneficial to CF patients. Successful in vitro transfection of CF airway epithelial cells with cationic vectors was possible with short incubation times. Heparin added at the end of the transfection incubation time could help to maintain the viability of the cells, without interfering with the transfection efficiency. It seems possible that heparin could be an adjuvant for non-viral mediated gene therapy.
46

Methodical improvements in microspore culture of Brassica napus L. / Methodische Verbesserungen in der Mikrosporenkultur von Brassica napus L.

Klutschewski, Sarah 14 February 2013 (has links)
Bei der routinemäßigen Anwendung der Mikrosporenkultur zur Herstellung doppelt-haploider Linien kommt es bis heute zu Engpässen in der praktischen Rapszüchtung. Die Hauptprobleme stellen eine unzureichende Colchizin-induzierte Diploidisierungsrate und eine niedrige direkte Regeneration von Pflanzen aus Mikrosporen-Embryonen dar. Ein hoher Prozentsatz an Rapsembryonen aus Mikrosporenkultur durchläuft den Prozess der sekundären Embryogenese, der eine zeitintensive Subkultivierung erfordert. Hierbei werden die direkten Sprossansätze wiederholt von undifferenziertem Gewebe freigeschnitten bis eine Überführung in Erde und die letztendliche Regeneration zu doppelt-haploiden Pflanzen möglich ist. Die vorliegende Doktorarbeit besteht aus zwei Studien, die sich mit dem Thema: „Methodische Verbesserungen der Mikrosporenkultur in Brassica napus L.“ auseinandersetzen. Ziel der ersten Studie war die Erhöhung der Colchizin-induzierten Diploidisierungsrate von Mikrosporen ohne die Regeneration von Pflanzen aus den Mikrosporen-Embryonen zu verringern und damit die Entwicklung zu doppelt-haploiden Pflanzen zu verzögern. Aufgrund der hohen Toxizität von Colchizin wurden die weniger toxischen Mitosehemmstoffe Amiprophos-methyl (APM) und Pronamid, die eine höhere Affinität zu Pflanzentubulin als Colchizin besitzen, allein und in Kombination mit Colchizin untersucht. Eine Kombination dieser Mitosehemmstoffe führte zu keiner effizienten Diploidisierungsrate; demnach konnte ein synergistischer Effekt ausgeschlossen werden. Die acht untersuchten Winterrapsgenotypen erzielten eine Diploidisierungsrate von 40% bis 64%. Die Mitosehemmstoff-Behandlungen der isolierten Mikrosporen variierten hierbei zwischen 33% (3 µM APM, 72 Stunden) und 70% (25 µM Colchizin, 72 Stunden). Ein signifikanter Einfluss der Mitosehemmstoffe auf die Konversionsrate der Mikrosporen-Embryonen konnte nicht nachgewiesen werden. In Abhängigkeit der Genotypen konvertierten 14% bis 23% direkt. Unterschiedliche getestete Colchizinkonzentrationen (250, 150, 125, 25 µM) zeigten für 4 untersuchte Genotypen eine Colchizin-induzierte Diploidisierungsrate von 58% bis 66%, wobei die Behandlung 250 µM Colchizin für 48h die höchste Rate aufwies. Ein signifikanter Einfluss von Dimethylsulfoxid (DMSO), das oftmals als Lösungsmittel der angewendeten Mitosehemmstoffe verwendet wird, konnte jedoch nicht in den untersuchten Konzentrationen (0,3% und 3%) in Kombination mit der Colchizin-Behandlung (250 µM, 72 Stunden) auf die Diploidisierungsrate und die direkte Konversionsrate nachgewiesen werden. Weiterhin wurden 17 Winterrapsgenotypen bezüglich ihrer spontanen und ihrer Colchizin-induzierten Diploidisierungsrate untersucht und deren Konversionsrate der Mikrosporen-Embryonen zu Regeneraten mit direkten Sprossansätzen bestimmt. Die ausgewählten Genotypen enthielten sowohl Sorten als auch F1–Hybriden. Die spontan-induzierte Diploidisierungsrate zeigte eine große Variation von 15% bis 69%. Im Vergleich dazu erreichte die Colchizin-induzierte Diploidisierungsrate Werte von 40% bis 83%. Die Mikrosporen-Embryonen der getesteten Genotypen wiesen ebenfalls eine große Spannbreite bezüglich ihrer direkten Konversionsrate auf. Die Ergebnisse zeigten keinen signifikanten Einfluss der Mitosehemmstoff-Behandlung auf den Regenerationserfolg der Mikrosporen-Embryonen zu Pflanzen. Sowohl die beobachtete spontane und die Mitosehemmstoff-induzierte Diploidisierung als auch die Konversionsrate der Mikrosporen-Embryonen zu Regeneraten mit direkten Sprossansätzen waren stark Genotyp-abhängig. Ziel der zweiten Studie war die Erhöhung der direkten Regeneration der Mikrosporen-Embryonen zu Pflanzen trotz der starken Abhängigkeit der Genotypen. Zunächst wurde der Einfluss von zehn unterschiedlichen Sprossregenerationsmedien mit und ohne Phytohormone (Gibberellinsäure, 6-Benzylaminopurin, 3-Indolylbuttersäure) und eine 14-tägige Kältebehandlung bei 4 °C (Lichtthermostat) auf die direkte Konversionsrate der Mikrosporen-Embryonen von 5 Winterrapsgenotypen untersucht. Die 14-tägige Kältebehandlung erfolgte sowohl unter acht Stunden Licht als auch in Dunkelheit. Die Standardkultivierung der Mikrosporen-Embryonen erfolgte im Kulturraum bei 26 °C und 12 Stunden Licht. 13% bis 39% der Mikrosporen-Embryonen konvertierten direkt, wobei die höchste Rate von 43% nach Kultivierung der Embryonen auf Gamborg B5-Medium mit 0.1 mg/L Gibberellinsäure resultierte. Die Mittelwerte der Konversionsrate der Mikrosporen-Embryonen zu Regeneraten mit direkten Sprossansätzen aller untersuchten Genotypen und Kulturmedien wurden durch die 14-tägige Kältebehandlung (28%) gegenüber der Standardkultivierung (14%) signifikant erhöht. Nachfolgend wurde der Einfluss der vier effizientesten Sprossregenerationsmedien und eine 14-tägige Kältebehandlung bei 1.5 °C und bei 4 °C (Lichtthermostat) auf die Konversionsrate von Mikrosporen-Embryonen von 13 Winterrapsgenotypen untersucht. Die Kältebehandlung bei 1.5 °C erfolgte unter Lichtabwesenheit als auch unter acht Stunden Licht. Die Kältebehandlung bei 4 °C erfolgte dagegen in Dauerlicht und Dauerdunkel. Zwischen 29% und 76% der Mikrosporen-Embryonen konvertierten direkt. Im Vergleich zur Kultivierung unter Standardbedingungen konnte mit der Kältebehandlung eine signifikante Erhöhung erzielt werden (von 21% auf bis zu 71%). Nach vorheriger Kultivierung der Mikrosporen-Embryonen auf den unterschiedlichen Kulturmedien variierte die Konversionsrate zwischen 50% (MS) und 60% (B5 mit 0.1 mg/L Gibberellinsäure). Die Ergebnisse der Untersuchungen zeigten, dass trotz einer vorherrschenden starken Abhängigkeit vom Genotyp, die direkte Konversionsrate der Mikrosporen-Embryonen mit Kältebehandlung (1.5 °C im Dauerdunkel) signifikant erhöht werden konnte. Fast alle Genotypen zeigten Konversionsraten der Mikrosporen-Embryonen von über 70%. Es ist demnach möglich die sekundäre Embryogenese und die damit verbundene zeitintensive in vitro-Subkultivierung erheblich zu reduzieren, und dadurch den Entwicklungsprozess von doppelt-haploiden Linien zur Verwendung in der praktischen Rapszüchtung zu beschleunigen.
47

Filme de quitosana para liberação controlada de colchicina para tratamento de carcinoma basocelular. / Chitosan film for controlled release of colchicine for treatment of basal cell carcinoma.

BRAZ, Adriana da Costa. 13 April 2018 (has links)
Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-04-13T18:27:12Z No. of bitstreams: 1 ADRIANA DA COSTA BRAZ - DISSERTAÇÃO PPG-CEMat 2014..pdf: 2523605 bytes, checksum: 90e198ea98d95b535e91044abaf7e15f (MD5) / Made available in DSpace on 2018-04-13T18:27:12Z (GMT). No. of bitstreams: 1 ADRIANA DA COSTA BRAZ - DISSERTAÇÃO PPG-CEMat 2014..pdf: 2523605 bytes, checksum: 90e198ea98d95b535e91044abaf7e15f (MD5) Previous issue date: 2014-12-12 / O Carcinoma basocelular é o câncer mais comum do mundo, e apesar da sua evolução muitas vezes benigna, com altas taxas de cura, algumas vezes nos deparamos com casos mais agressivos, invasivos, destrutivos e de difícil controle. É sabido que já houve avanços terapêuticos para estes casos específicos, a exemplo do Vismodegib, entretanto o uso desta droga ainda é uma realidade distante para nossos pacientes brasileiros que se expõe a índices elevados de radiações solares, na maioria trabalhadores rurais de baixa renda e com grande dificuldade a acessibilidade ao sistema público de saúde. Por isso, o presente trabalho sugere uma alternativa para o controle das formas graves do carcinoma basocelular, através da produção de um filme de quitosana dopado de colchicina substância sabidamente antimitótica e com evidência clínica já citada na literatura no carcinoma basocelular, por via transdérmica por liberação controlada da droga que permita mantê-la em um nível sérico contínuo, suficiente para sua ação antimitótica, causando morte seletiva das células tumorais, diminuindo ou extirpando esses tumores, com custos mais acessíveis, pois é uma droga de baixo custo, melhorando consequentemente a morbidade da doença e a qualidade de vida destes pacientes. E os resultados obtidos através das caracterizações apresentaram membranas com variações de cristalinidade (por DRX) de acordo com o processo de reticulação. Por FTIR pode-se observar certa interação entre o fármaco e os grupos amina da quitosana. Pelas microscopias ótica e eletrônica, pode-se observar que o acréscimo de fármaco proporcionou alguma rugosidade a membrana. Também pelas microscopias verificou-se a reticulação não homogênea da superfície da membrana. Por EDS não se verificou nenhum elemento estranho a estrutura da quitosana e do fármaco. Por medida do ângulo de molhabilidade pode-se verificar aumento do perfil hidrofílico da membrana por adição do fármaco, perfil este que foi modificado pelo processo de reticulação. A partir do ensaio de citotoxicidade pode-se constatar que a membrana apresenta certa citotoxicidade. Este resultado demonstra também o potencial da membrana de quitosana em liberar o fármaco, considerando que a membrana apenas de quitosana não apresenta toxicidade em meio biológico, sendo a toxicidade observada no ensaio decorrente do fármaco liberado. / Basal cell carcinoma is the most common cancer in the world, and despite its evolution often benign, with high cure rates, sometimes we are faced with more aggressive, invasive cases, destructive and difficult to control. It is known that there have been advances in treatment for these specific cases, such as the Vismodegib, however this drug is still a distant reality for our Brazilian patients who are exposed to high levels of solar radiation in most rural workers from low-income, great difficulty accessibility to the public health system. Therefore, this study suggests an alternative for the control of severe forms of basal cell carcinoma, through the production of a chitosan film doped colchicine known antimitotic substance and with clinical evidence already mentioned in the literature in basal cell carcinoma, transdermally for release controlled drug that allows keep at a steady serum level, enough for their antimitotic, causing selective killing of tumor cells, reducing or extirpating these tumors, with more affordable because it is an inexpensive drug, consequently improving morbidity the disease and the quality of life of these patients. And the results obtained from the characterization showed membranes crystallinity variations (XRD) according to the crosslinking process. By FTIR one can observe some interaction between the drug and amino groups of chitosan. Through optical and electronic microscopy, it can be seen that addition of drug has provided some roughness to the membrane. Also by microscopy verified the inhomogeneous crosslinking of the membrane surface. EDS there was no foreign object the structure of chitosan and the drug. By measuring the wetting angle can be checked increase the hydrophilic profile of the drug by adding the membrane, this profile has been modified by the crosslinking process. From the cytotoxicity assay can be seen that the membrane has some cytotoxicity. This result also demonstrates the potential of chitosan membrane to release the drug, whereas only chitosan membrane shows no toxicity in biological medium, with the toxicity observed in this trial due to the released drug.
48

Duplicação cromossômica em plantas: Solanum melongena L. como modelo

Neves, Camila Siqueira 24 March 2017 (has links)
Submitted by isabela.moljf@hotmail.com (isabela.moljf@hotmail.com) on 2017-08-18T11:32:50Z No. of bitstreams: 1 camilasiqueiraneves.pdf: 1794675 bytes, checksum: f6798de20bc50ab506f3f25f990c23c2 (MD5) / Rejected by Adriana Oliveira (adriana.oliveira@ufjf.edu.br), reason: on 2017-08-24T11:25:19Z (GMT) / Submitted by isabela.moljf@hotmail.com (isabela.moljf@hotmail.com) on 2017-08-24T15:09:20Z No. of bitstreams: 0 / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-08-30T14:20:42Z (GMT) No. of bitstreams: 0 / Made available in DSpace on 2017-08-30T14:20:42Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-03-24 / A indução de poliploidia é uma ferramenta muito empregada em programas de melhoramento de plantas, mas geralmente resulta em baixa eficiência e elevada taxa de indivíduos mixoploides ou aneuploides. Poliploides artificiais podem ser obtidos pela utilização de antimitóticos, que interferem na formação do fuso durante a divisão celular. Dentre eles, a colchicina é o mais empregado em estudos de poliploidia. No entanto, os mecanismos responsáveis por sua ação sobre as células ainda não foram totalmente elucidados. Solanum melongena L. (berinjela) apresenta tecidos com elevado potencial de regeneração in vitro, característica interessante para o desenvolvimento de estudos básicos e biotecnológicos. O presente trabalho teve como objetivo utilizar a berinjela como modelo para o estudo do processo de duplicação cromossômica em plantas. Foram empregadas técnicas de citogenética, citometria de fluxo e indução de poliploidia in vitro. O capítulo I destinou-se à caracterização citogenética da cultivar Embu de berinjela, que foi empregada em todos os experimentos. Esta cultivar apresentou 24 cromossomos, com tamanho variando entre 1,77 e 2,63 μm. O caritóripo mostrou-se simétrico e foram observadas duas constrições secundárias. Através do bandeamento com fluorocromos CMA3 e DAPI, foram observadas quatro bandas CMA positivas. A técnica de FISH permitiu a visualização de um par de sinais para a sonda DNAr 5S e dois pares para a sonda DNAr 45S. O capítulo II teve como objetivo avaliar os efeitos da colchicina (0,2% e 0,02%) sobre o ciclo celular de berinjela e a eficiência destas concentrações no processo de indução de poliploidia. De forma pioneira, a hidroxiureia foi utilizada como sincronizador do ciclo celular, com o intuito de aumentar a eficiência da poliploidização. A avaliação do ciclo celular foi conduzida em meristemas radiculares com e sem a sincronização e as análises foram realizadas por microscopia e citometria de fluxo. A indução de poliploides in vitro, por sua vez, foi realizada em sementes e segmentos nodais sincronizados e não sincronizados. Não foram observadas diferenças significativas em relação ao índice mitótico. Maiores percentuais de cmetáfases, metáfases duplicadas e núcleos poliploidizados (2xG2) foram observados em resposta à maior concentração de colchicina (0,2%). Os protocolos de indução de poliploidia testados mostraram-se eficientes, sendo regeneradas plantas poliploides após todos os tratamentos. Dos 480 explantes tratados com colchicina, 342 foram regenerados com sucesso, sendo 45 tetraploides e 90 mixoploides. / Polyploidy induction is an important tool in plant breeding, but usually results in low efficiency and high rates of mixoploid and aneuploid plants. Synthetic polyploids can be obtained by the exposure to antimitotic agents, which interfere with the spindle formation during cell division. Colchicine is the most widely used antimitotic in polyploidy induction studies. However, the underlying mechanisms of its action on cells are not completely clear. Solanum melongena L. (eggplant) has a great in vitro regeneration capacity, an interesting feature to the development of basic and biotechnological studies. This work aimed to use eggplant as a model to study the process of chromosome doubling in plants. Cytogenetic techniques, flow cytometry and in vitro polyploidy induction were performed. Chapter I focused on the cytogenetic characterization of the cultivar Embu of eggplant, which was used in all experiments. This cultivar presented 24 chromosomes with length ranging from 1.77 to 2.63 μm. The karyotype was symmetrical and two secondary constrictions were observed. The CMA3/DAPI banding showed four CMA positive bands. The FISH technique allowed the observation of one pair of sites of 5S rDNA and two pairs of 45S. The objective of chapter II was to evaluate the effects of colchicine (0.2% and 0.02%) on the eggplant cell cycle and the efficiency of these concentrations in the polyploidy induction. Innovatively, hydroxyurea was used as a cell cycle synchronizer, in an attempt to increase the efficiency of polyploidization. The cell cycle evaluation was conducted in root meristems with and without cell synchronization and the analysis were performed by light microscopy and flow cytometry. In vitro induction of polyploidy was performed on synchronized and non-synchronized seeds and nodal segments. No significant differences were detected in the mitotic index. Higher frequencies of c-metaphases, polyploid metaphases and polyploid nuclei (2xG2) were observed after the exposure to the higher treatment with colchicine (0.2%). The polyploidy induction protocols tested were efficient, with the regeneration of polyploid plants after all colchicine treatments. Of the 480 treated explants, 342 were successfully regenerated, being 45 tetraploids and 90 mixoploids.
49

Estudo do envolvimento da neuraminidase 1 no processo de autofagia na musculatura esquelética / Larina Neto R. Neuraminidase 1 involvement in the autophagy process in the skeletal muscles

Larina Neto, Rubens de 18 July 2019 (has links)
INTRODUÇÃO:A neuraminidase 1 (chamada a seguir por Neu1) regula o catabolismo de sialoglicoconjugados nos lisossomos. A deficiência congênita da Neu1 é a base da sialidose, doença neurossomática grave associada a deformidades osteoesqueléticas, hipotonia e fraqueza muscular. Camundongos com deficiência de Neu1 desenvolvem uma forma atípica de degeneração muscular caracterizada porproliferação anormal de fibroblastoslevando a invasão nas fibras musculares, expansão da matriz extracelular (MEC), fragmentação do citoplasma, formação vacuolar e atrofia muscular. A ocorrência de atrofia muscular indica que a deficiência da Neu1 podeestar relacionada com o controle da massa muscular, a qual é dependente do equilíbrio entre síntese e degradação proteica.Uma característica principalnaMacroautofagia (denominada a seguir por autofagia) é a principal via de degradação intracelular sendo expressamente essencial para a homeostase celular e remoção de materiais citoplasmáticos. Objetivos: Avaliarseos efeitos da deficiência da Neuraminidase 1 afetama indução de autofagia e a formação de autofagossomos e determinar os efeitos do bloqueio da função lisossomal sobre o fenótipo muscular na deficiência da Neuraminidase1.Metodologia:Camundongos Neu1+/-foram cruzados e os filhotes genotipados, onde camundongos Neu1-/-(nocaute) e Neu1+/+(normal),foram utilizados no estudon total=90, sendo 10 em padronizações, 20 para coleta de fibroblastos e 60 para procedimentos in vivo, os grupos experimentais foram divididos em privação alimentar por 2 dias que, por meio da inibição do mTOR, induz a autofagia;grupo detratamento com Colchicina por 4 dias onde irá impedir a junção autofagossomo/lisossomonão havendo a degradaçãolisossomaleadicionado nos dois últimos dias de privação alimentar e o grupo de tratamento comRapamicina por 7 dias, droga com função de inibir seletivamente o mTOR.Após os tratamentos, os animais foram eutanasiadospara coleta dos músculos gastrocnêmios e tibiais anterior. Os músculos foram analisados apósas coloraçõeshistológicas porHematoxilina & Eosina e Fosfatase Ácida; Imunofluorescência de LC3-I/II; Western Blottingdas proteínas LC3-I/II, Lamp-1 e p62/SQSTM e a análise Ultra-estrutural. Além disso, foi realizada cultura de fibroblastos, os quais foram submetidos à privação de nutrientes e ao tratamento com Rapamicina, seguidos dasmesmas metodologias de análise invivo. Resultados:As análises histológicas através de H&E e Fosfatase Ácida não revelaram alterações consistentes na musculatura esquelética de animais submetidos aos tratamentos, mostrando em animais com deficiência de Neu1 um aumento anormal do espaço endomisial, e aumento da atividade lisossomalintracitoplasmáticos. Na análise ultra-estruturalobservou-se em todos os grupos, a presença de diversas estruturas com aspecto autofágico, de diferentes tamanhos, formas e constituintes. Naanálise da expressão do LC3 através de Western Blottingmostrou importante ativação do LC3-II na privação alimentar (com e sem administração de Colchicina) tanto em animais controles quanto em animais com deficiência de Neu1 e uma importante ativação do LC3-I em Rapamicina em ambos os grupos mostrando assim que houve um aumento da via da autofagia através do bloqueio do mTOR. Já na análise de Imunofluorescência não foi possível observar diferença consistenteentre os grupos.A análise in vitrode Western Blottingmostrou que tal ativação foi similar entre fibroblastos Neu1+/+e Neu1-/-. Conclusão:Os experimentos relacionados com a ativação ou inibição da autofagia, não resultaram em diferenças consideráveis entre músculos normais e músculos com deficiência de Neu1. Desta forma, podemos concluir com estes experimentos que aparentemente a Neu1, apesar de ser uma importante enzima lisossomal, não interfere com o processo de autofagia / Introduction:Neuraminidase 1 (hereinafter Neu1) regulates the catabolism of sialoglycoconjugates in lysosomes. The congenital deficiency of Neu1 is the basis of sialidosis, a severe neurosomatic disease associated with osteo-skeletal deformities, hypotonia, and muscle weakness. Mice with Neu1deficient develop an atypical form of muscle degeneration characterized by abnormal fibroblast proliferation leading to muscle fiber invasion, extracellular matrix expansion (ECM), cytoplasm fragmentation, vacuolar formation, and muscle atrophy. The occurrence of muscle atrophy indicates that deficiencyofNeu1 may be related to the control of muscle mass, which is dependent on the balance between synthesis and protein degradation. A major feature in Macroautophagy (hereinafter referred to as autophagy) is the main pathway of intracellular degradation being expressly essential for cellular homeostasis and removal of cytoplasmic materials. Objectives:To evaluate whether the effects of neuraminidase 1 deficiency affect autophagy induction and autophagosome formation and to determine the effects of lysosomal function block on muscle phenotype in neuraminidase 1 deficiency. Methodos:Mice Neu1+/-were crossbred and the genotyped pups, where mice Neu1-/-(knockout) and Neu1+/+(normal), were used in the study ntotal = 90, 10 for standardization, 20 for fibroblast collection and 60 for in vivo procedures, experimental groups were divided into food deprivation for 2 days that, through mTOR inhibition, induces autophagy; Colchicine treatment group for 4 days whereit will prevent autophagosome/lysosome junction without lysosomal degradation and added in the last two days of food deprivation and Rapamycin treatment group for 7 days, drug with function to selectively inhibit mTOR. After the treatments, the animals were euthanized to collect the anterior gastrocnemius and tibial muscles. The muscles were analyzed after histological staining by Hematoxylin & Eosin and Acid Phosphatase; LC3-I/II immunofluorescence; Western Blottingof LC3-I/II, Lamp-1 and p62/SQSTM proteins and Ultra-structural analysis. In addition, fibroblasts were cultured and subjected to nutrient deprivation and Rapamycin treatment, followed by the same in vivo analysis methodologies. Results:Histological analyzes by H&E and Acid Phosphatase did notreveal consistent changes in skeletal muscle of animals submitted to treatments, showing in animals with Neu1 deficiency an abnormal increase in endomysial space and increased intracytoplasmic lysosomal activity.In ultrastructural analysis, it was observed in all groups, the presence of several structures with autophagic aspect, of different sizes, shapes and constituents. The analysis of LC3 expression by Western Blottingshowed important activation of LC3-II in food deprivation (with and without Colchicine administration) in both control and Neu1 deficient animals and an important activation of LC3-I in Rapamycininboth groups,thus showing an increase in the autophagy pathway through mTOR blockade. In the immunofluorescence analysis, it was not possible to observe consistent difference between the groups. In vitro Western Blottinganalysis showed that such activation was similar between Neu1+/+and Neu1-/-fibroblasts. Conclusion: Experiments related to activation or inhibition of autophagy did not result in considerable differencesbetween normal muscles and Neu1 deficient muscles. Thus, we can conclude from these experiments that apparently Neu1, despite being an important lysosomal enzyme, does not interfere with the autophagy process
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Citogenética, quantidade de DNA e indução de poliploidia em Pfaffia glomerata Spreng

Gomes, Shaiany Sabrina Lopes 28 February 2013 (has links)
Submitted by isabela.moljf@hotmail.com (isabela.moljf@hotmail.com) on 2017-05-05T15:13:46Z No. of bitstreams: 1 shaianysabrinalopesgomes.pdf: 1892834 bytes, checksum: bffd5bff4b38c8f75f7aca75cbd5160b (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-05-17T13:40:45Z (GMT) No. of bitstreams: 1 shaianysabrinalopesgomes.pdf: 1892834 bytes, checksum: bffd5bff4b38c8f75f7aca75cbd5160b (MD5) / Made available in DSpace on 2017-05-17T13:40:45Z (GMT). No. of bitstreams: 1 shaianysabrinalopesgomes.pdf: 1892834 bytes, checksum: bffd5bff4b38c8f75f7aca75cbd5160b (MD5) Previous issue date: 2013-02-28 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico / FAPEMIG - Fundação de Amparo à Pesquisa do Estado de Minas Gerais / O gênero Pfaffia (Amaranthaceae) compreende 33 espécies distribuídas na Região Neotropical. Graças a algumas substâncias químicas encontradas no gênero que se assemelham àquelas encontradas no gênero Panax (ginseng coreano), a espécie Pfaffia glomerata é conhecida “ginseng brasileiro ”. Tal planta é utilizada como tônico, afrodisíaco, rejuvenescedor, anti-fadiga, antiestresse e contra distúrbios gástricos. Suas propriedades medicinais são atribuídas a compostos encontrados principalmente em suas raízes tuberosas, sendo a β-ecdisona a mais visada pela indústria farmacêutica e cosmética. Apesar de sua importância econômica e medicinal, são poucos os estudos que investigam aracterísticas genéticas da espécie. Neste trabalho foram feitas análises citométricas e cromossômicas de fáfias diploide e poliploide induzida. A poliploidização se deu por duplicação cromossômica in vitro com uso de agentes antimitóticos (colchicina e orizalina) em diferentes concentrações e tempo de exposição. A quantidade de DNA encontrada foi de 2,41 pg (2n=34) e 4,79 pg (2n=68). O genoma de P. glomerata diploide e tetraploide foi analisado por técnicas de coloração convencional e coloração diferencial dos cromossomos por bandamento com CMA3/DA/DAPI e FISH para DNAr. Embora os cromossomos da espécie sejam pequenos, foi possível identificar suas constrições primárias e encontrar um par de cromossomos com satélite no representante diploide e dois pares no poliploide. Foram montados cariogramas e idiogramas, sendo que as fórmulas cariotípicas foram: 16M + 1SM para o genoma 2n=34 e 32M + 2SM para o genoma 2n=68. Os núcleos interfásicos mostraram-se reticulados. Através do bandeamento com CMA3/DA/DAPI observou-se que todos os cromossomos possuem bandas centroméricas DAPI+, indicando uma região heterocromática ao redor dos centrômeros. Foi localizada uma banda CMA+ no braço curto de um dos cromossomos, sendo registrada diferença na extensão da banda entre os homólogos. O emprego da FISH com as sequências de DNAr 45S e 5S, gerou para cada tipo de sonda, dois sinais em um par de homólogos para o genoma diploide e quatro sinais no genoma poliploide. Os cromossomos homólogos apresentaram heteromorfismo para as regiões de DNAr invetigadas. O teor de β-ecdisona presente no extrato metanólico das raízes de fáfia com quatro meses de cultivo, foi de 0,32% para a planta diploide e 0,48% para a poliploide sugerindo um aumento de 50% na produção do composto no poliploide quando comparado com seu diploide. A estrutura do grão de pólen, determinada por acetólise Erdtman, mostrou-se estável entre acessos diploides da espécie. Este é o primeiro relato da quantidade de DNA no gênero Pfaffia. Também são inéditos os dados obtidos por FISH com sondas para DNAr 45S e 5S para a P. glomerata diploide e poliploide. Os resultados da quantificação do teor de β-ecdisona sugerem a duplicação cromossômica como alternativa para incremento do valor econômico da espécie. / The genus Pfaffia (Amaranthaceae) comprises 33 species distributed in the neotropics. Thanks to some chemicals found in the genus that resemble those found in the genus Panax (Korean ginseng), the species P. glomerata is known as "Brazilian ginseng". P. glomerata is commonly used as tonic, phrodisiac, rejuvenator, anti-fatigue, anti-stress and against gastric disorders. Its medicinal properties are attributed to the compounds mainly found in their tuber roots, being the β-ecdysone the most explored by the pharmaceutical and cosmetic industries. Despite its economical and medicinal importance, few studies have been done to investigate the genetic aspects of the species. In this work, cytometric and chromosomal analyzes were made with diploid and induced polyploid of P. glomerata. The polyploidization occurred by in vitro chromosome doubling, using antimitotic agents (colchicine and oryzalin) at different concentrations and exposure times. Flow cytometry analysis showed 2.41 pg (2n = 34) and 4.79 pg (2n = 68) of DNA amounts. Both P. glomerata diploid and tetraploid were analyzed by conventional staining techniques and chromosomal differential staining by CMA3/DA/DAPI banding and rDNA FISH. In spite of the small sizes of chromosomes, it was possible to identify their primary constrictions and a pair of satellites chromosomes in the diploid and two pairs in the polyploid. Karyograms and idiograms were assembled. Karyotypic formulas were 16M + 1SM considering the 2n = 34 genome and 32M + 2SM considering 2n = 68. The interphase nuclei seem to reticulated. The fluorochrome CMA3/DA/DAPI banding revealed all chromosomes with centromeric DAPI+ bands indicating a heterochromatic region around the centromeres. A CMA+ band, with different extension between the homologous was observed on the short arm of one chromosome pair. The FISH technique with rDNA 45S and 5S sequences revealed two signals to each probe for the diploid genome and four signals in the polyploid genome. Homologous chromosomes are heteromorphic when considering the rDNA regions here investigated. The content of β ecdysone present in the methanol extract of the roots of P. glomerata with four months of cultivation was 0.32% for the diploid and 0.48% for the tetraploid suggesting an increase of 50% on the tetraploid comparing with the diploid. Pollen structure was determined by Erdtman acetolysis, and no differences were observed between diploid accessions. This is the first report of DNA amount in the genus Pfaffia and data obtained with FISH using 45S and 5S rDNA probes have not been published elsewhere. The β-ecdysone quantification suggests that chromosome duplication is an alternative to increase the economical value of the species.

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