RESUMEN
Beauveria bassiana genetic diversity and ability to synthesize quercetin 2,3-dioxygenase (quercetinase) were analyzed. B. bassiana isolates, obtained from Brazilian soil samples, produced quercetinase after induction using 0.5 g/L quercetin. B. bassiana ATCC 7159 (29.6 nmol/mL/min) and isolate IP 11 (27.5 nmol/ml/min) showed the best performances and IP 3a (9.5 nmol/mL/min) presented the lowest level of quercetinase activity in the culture supernatant. A high level of polymorphism was detected by random amplified polymorphic DNA (RAPD) analysis. The use of internal-transcribed-spacer ribosomal region restriction fragment length polymorphism (ITS-RFLP) did not reveal characteristic markers to differentiate isolates. However, the ITS1-5.8S-ITS2 region sequence analysis provided more information on polymorphism among the isolates, allowing them to be clustered by relative similarity into three large groups. Correlation was tested according to the Person's correlation. Data of our studies showed, that lower associations among groups, level of quercetinase production, or geographical origin could be observed. This study presents the production of a novel biocatalyst by B. bassiana and suggests the possible industrial application of this fungal species in large-scale biotechnological manufacture of quercetinase.
Asunto(s)
Secuencia de Bases , Beauveria/genética , Beauveria/aislamiento & purificación , Activación Enzimática , Hongos Mitospóricos/enzimología , Hongos Mitospóricos/genética , Regulación de la Expresión Génica , Variación Genética , Técnicas In Vitro , Quercetina/análisis , Quercetina/genética , Técnicas Genéticas , Métodos , VirulenciaRESUMEN
Microbial biotransformations constitute an important alternative as models for drug metabolism study in mammalians and have been used for the industrial synthesis of chemicals with pharmaceutical purposes. Several microorganisms with unique biotransformation ability have been found by intensive screening and put in commercial applications. Ten isolates of Beauveria sp genus filamentous fungi, isolated from soil in the central Brazil, and Beauveria bassiana ATCC 7159 were evaluated for their capability of quercetin biotransformation. Biotransformation processes were carried out for 24 up to 96 hours and monitored by mass spectrometry analyses of the culture broth. All strains were able to metabolize quercetin, forming mammalian metabolites. The results were different from those presented by other microorganisms previously utilized, attrackting attention because of the great diversity of reactions. Methylated, sulphated, monoglucuronidated, and glucuronidated conjugated metabolites were simultaneously detected.
Biotransformações microbianas constituem uma alternativa importante como modelo para o estudo do metabolismo de medicamentos em mamíferos e são empregadas em processos sintéticos industriais com propósitos farmacêuticos. Diversos microrganismos com potencial para biotransformação têm sido encontrados através de screening intensivo e aplicados comercialmente. Dez cepas de fungos filamentosos do gênero Beauveria, isolados na região central do Brasil, e a cepa Beauveria bassiana ATCC 7159 foram avaliadas quanto à capacidade de biotransformação da quercetina. As reações de biotransformações foram realizadas por um período de 24 a 96 horas, e monitoradas através de espectrometria de massas do meio reacional. Todas as cepas foram capazes de metabolizar a quercetina, formando metabólitos encontrados nos mamíferos. Os resultados foram diferentes dos resultados apresentados por outros microrganismos utilizados anteriormente e chamam a atenção devido à diversidade das reações evidenciadas. Diferentes metabólitos conjugados foram detectados simultaneamente: metilados, sulfatados, monoglicuronados, e glicuronados.