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Master's Dissertation
DOI
https://doi.org/10.11606/D.87.2019.tde-13012021-161456
Document
Author
Full name
Bruna Souza da Silva
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 2019
Supervisor
Committee
Silva Junior, Pedro Ismael da (President)
Ferreira, Rita de Cassia Cafe
Oliveira, Ricardo Pinheiro de Souza
Silva, Fernanda Dias da
Title in Portuguese
Prospecção de moléculas bioativas sintetizadas por Lactobacillus acidophilus
Keywords in Portuguese
Lactobacillus acidophilus
Bacilos de Doderlein
Bactérias ácido-lácticas
Bacteriocinas
Peptídeos antimicrobianos
Abstract in Portuguese
Os Lactobacillus acidophilus são um grupo de bactérias Gram-positivas intimamente associadas, que se distribuem por diversos ambientes e possuem relevância para o ser humano, pois são componentes da microbiota normal de seus tratos gastrointestinal e urogenital. São classificados como bactérias ácido-lácticas (BAL) devido à produção de ácido láctico. Contudo, outro composto sintetizado por estes procariontes tem se destacado nas últimas décadas: as bacteriocinas. Bacteriocinas são peptídeos e proteínas, produzidos por bactérias, capazes de inibir o crescimento de outros microrganismos, para fins de competição por recursos do ambiente. Devido ao uso indiscriminado dos antibióticos convencionais e ao surgimento das bactérias multirresistentes, as bacteriocinas tem se tornado uma opção no tratamento de infecções, confecção de produtos probióticos e na conservação de alimentos. Sendo assim, o presente estudo teve como objetivo isolar e caracterizar peptídeos antimicrobianos produzidos por Lactobacillus acidophilus. As amostras foram obtidas do sobrenadante de extratos ácidos dos Lactobacillus e submetidas a um pré-fracionamento em colunas SEP-PAK C18 descartáveis e em seguida, à cromatografia líquida de alta eficiência (CLAE). As frações coletadas foram utilizadas em ensaios de inibição do crescimento microbiano em meio líquido. Foram obtidas oito frações com atividade antimicrobiana. Duas delas, com massas moleculares de 1788 e 1074 Da, foram selecionadas para a caracterização por apresentarem atividade contra C. albicans e por seus melhores resultados nas análises bioinformáticas. A molécula de 1788 Da foi sequenciada, denominada Doderlina e sintetizada com o intuito de ampliar os estudos sobre seu potencial biológico. Peptídeos bioativos e bacteriocinas isolados de L. acidophilus já foram descritos em outros estudos, contudo até o presente momento, não foi encontrado na literatura nenhum outro relato de peptídeos bioativos de L. acidophilus que fossem eficazes contra C. albicans como encontrado neste estudo, indicando que estas bactérias podem contribuir com o tratamento da candidíase, que não está sob controle e tende a aumentar sua prevalência na população.
Title in English
Prospecting bioactive molecules synthesized by Lactobacillus acidophilus.
Keywords in English
Lactobacillus acidophilus
Antimicrobial peptides
Bacteriocins
Doderlein\'s bacilli
Lactic acid bacteria
Abstract in English
Lactobacillus acidophilus is a group of closely associated Gram-positive bacteria that are distributed in various environments and have relevance to humans, as they are components of the normal microbiota of their gastrointestinal and urogenital tract. They are classified as lactic acid bacteria (BAL) due to the production of lactic acid. However another compound synthesized by these prokaryotes has stood out in recent decades: bacteriocins. Bacteriocins are peptides and proteins produced by bacteria capable of inhibiting the growth of other microorganisms for the purpose of competition for environmental resources. Due to the indiscriminate use of conventional antibiotics and the emergence of multi-resistant bacteria, bacteriocins have become an option in treating infections, probiotic products confection and food conservation. Thus, the present study aimed to isolate and characterize antimicrobial peptides produced by Lactobacillus acidophilus. Samples were obtained from Lactobacillus acid extract supernatant and pre-fractionated on disposable SEP-PAK C18 columns and then by high performance liquid chromatography (HPLC). The collected fractions were used in microbial growth inhibition assays in liquid medium. Eight fractions with antimicrobial activity were obtained. Two of them with molecular masses of 1788 and 1074 Da were selected for characterization because they showed activity against C. albicans and for their best results in bioinformatics analysis. The 1788 Da molecule was sequenced, named Doderlin and synthesized in order to expand the studies on its biological potential. Bioactive peptides and bacteriocins isolated from L. acidophilus have already been described in other studies, however to date no other reports of L. acidophilus bioactive peptides that were effective against C. albicans as was found in this study have been found in the literature, indicating that these bacteria may contribute to the treatment of candidiasis that is not under control and increases its prevalence in the population.
 
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Release Date
2023-01-13
Publishing Date
2021-10-13
 
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