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Master's Dissertation
DOI
https://doi.org/10.11606/D.42.2020.tde-04012022-094334
Document
Author
Full name
Lucas Sousa Neves Andrade
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 2020
Supervisor
Committee
Maldonado, Gabriel Padilla (President)
Oliveira, Ricardo Pinheiro de Souza
Silva, Luiziana Ferreira da
Sousa, Cristina Paiva de
Title in Portuguese
Identificação e caracterização de clusters biossintéticos de Micromonospora sp.
Keywords in Portuguese
Micromonospora sp.
Antitumorais
Antraciclinas
Clusters biossintéticos
Microrganismos marinhos
Abstract in Portuguese
Bioprodutos de origem marinha tem sido intensamente explorados nas últimas décadas devido à grande diversidade de moléculas de tipos não encontrados em outros ambientes das quais muitas apresentam potencial farmacológico, destacando-se o potencial de descoberta de antitumorais. Em estudo conduzido por grupo de pesquisadores da Universidade Federal do Ceará, realizado na costa cearense, foram isoladas vinte cepas de microrganismos da áscidia Eudistoma vannamei, para realização de triagem de compostos antitumorais. Após testes de teor qualitativo, cinco cepas do gênero Micromonospora sp. se destacaram por seu potencial como antitumoral. Estas foram submetidas a um ensaio de MTT quantitativo, determinando-se o IC 50, que variou de 3.62 a 84 μg mL. Posteriormente, o mesmo grupo realizou o fracionamento e caracterização de compostos a partir do extrato de EVA 0109, resultando em 4 complexos. Foi realizado novo ensaio MTT quantitativo, obtendo-se, para o composto 1, IC50 de 12,7μM, para composto 4, 6,2 μM, enquanto os compostos 2 e 3 foram considerados inativos (IC50 maior que 70 μM). Ao contrário do esperado, estes resultados foram menos expressivos que os obtidos com os extratos brutos. Em geral as antraciclinas são cerca de 100 vezes mais ativas que suas respectivas agliconas. Com a perspectiva de aumento de casos de câncer nas próximas décadas e ainda limitada efetividade das terapias atuais, é fundamental a obtenção e compreensão da atividade de novas moléculas, assim como a entendimento da biossíntese dos compostos para posterior interferência para obtenção de produtos melhorados. Este trabalho procurou, então analisar o genoma da linhagem BRA 006 A, cujo extrato bruto havia apresentado resultados mais relevantes nos testes de atividade antitumoral dos trabalhos anteriores, verificar se há cluster gênico completo para síntese de antraciclina e caracterizar a cepa através da construção de arvore fenética. BRA 006 A apresenta genoma com características típicas de Micromonospora sp. como tamanho do genoma (aproximadamente 6,73 Mbp) e conteúdo GC (73%) dentro da média do gênero e presença de cluster de metabólitos secundários sempre encontrados em genomas de representantes do grupo como sioxanthin, alkyl-o-dihydrogeranylmethohydroquinone e lymphostin. Com base nos resultados da arvore fenética, construída a partir de MLSA, supõe-se que se trata de uma espécie ainda não identificada, cuja cepa conhecida mais próxima é Micromonospora tulbaghiae DMS45142 e as características do genoma corroboram os resultados da árvore, estando dentro dos valores médios do subgrupo. Identificou-se através das diversas ferramentas de bioinformática utilizadas, um cluster completo de uma antraciclina que os levantamentos bibliográficos indicam que seja potencialmente nova. Os açúcares apresentam padrão de metilação também não encontrado em estruturas descritas, de acordo com a pesquisa bibliográfica. Além do cluster de antraciclina, foram encontrados outros clusters com potencial interesse para a investigação de moléculas de interesse farmacológico, como 2 clusters de lantipeptídeo, 1 de bacteriocinas, 6 terpenos, 7 NRPSs, 2 do tipo PKS 2 (incluindo o cluster de antraciclina) e 4 do tipo PKS I, incluindo cluster que apresenta similaridade com 44% dos genes do cluster de Stambomycin, composto com potencial antitumoral relatado.
Title in English
Identification and charactarization of biosynthetics clusters of Micromonospora sp.
Keywords in English
Micromonospora sp.
Anthracyclins
Antitumor
Biosyntheic clusters
Marine microorganisms
Abstract in English
Marine bioproducts have been intensively explored in recent decades, due to the great diversity of molecules not found in other environments which may have pharmacological potential, highlighting the probability of an antitumoral new discovery. In a previous study conducted at Federal University of Ceará, carried out in the coast of Ceará state, twenty microorganisms strains were isolated from the ascidia Eudistoma vannamei and screened for production of antitumor compounds. After qualitative tests five Micromonospora sp. strains showed antitumoral activity. These were subject to a quantitative MTT assay, determining the IC50, which ranged from 3.62 to 84 ug ml-1. Subsequently, it was performed the fractionation and characterization of compounds from EVA 0109 extract, resulting in 4 complexes. A new quantitative MTT assay was performed, yielding 12.7 uM IC 50 for compound 4, while compounds 2 and 3 were considered inactive (IC50 greater than 70 uM). Contrary to expectations, these results were less expressive than those obtained with crude extracts. In general anthracyclines are almost 100 times more active than their respective aglycones. With the prospect of increasing cancer cases in the coming decades, and still the limited effectiveness of current therapies, it is essential to obtain and understand the activity of new molecules, as well as understanding the biosynthesis of compounds for later inference to obtain improved products. This work analysed the genome of BRA 006A strain, whose crude extract had shown relevant results in the antitumor activity tests in previous work, and also to verify if there is a complete gene cluster for anthracycline synthesis and to characterize the strains though the construction of a phylogenetic tree. Several bioinformatics tools were used to identify a complete anthracycline cluster. The new potential encoded anthracycline has not been described in the literature. Sugars have also a methylation pattern no described. BRA 006 A presents genome with Micromonospora sp. typical characteristics such genome size (6.73 Mbp) and GC content ( 73%) with values in the range observed for the genus and the presence of several secondary metabolite cluster frequently found were present such as sioxanthin, alkyl-o-dihydrogeranylmethohydroquinone and lymphostin. Based in the results of the fenetic tree, built by MLSA, it is supposed that BRA 006 A is a unidentified species whose nearest known strain is Micromonospora tulbaghiae DMS45142. The characteristics of the genome were validated with the results of the tree, because is observed the subgroup mean values. A complete anthracycline cluster was identified by several bioinformatics tools, the bibliographic surveys indicates that is a potential new compound. The sugars residues present methylation pattern not observed in the structures described in the consulted literature. In addition to the anthracycline cluster, other clusters with potential interest for the investigation of molecules of pharmacological significance were found, such as two lantipeptide clusters, one of bacteriocins, seven of NRPS's, six of terpenes, two of PKS II (that include the anthracycline cluster) and four of PKS I, include one that present similarity with 44% of the genes of Stambomycin cluster, compound with related antitumoral potential.
 
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Publishing Date
2022-01-07
 
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