Microbiologia

URI permanente desta comunidadehttps://locus.ufv.br/handle/123456789/11840

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2008 - 200912010 - 20152

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Autor: search.filters.author.Araújo, E.F. deData inicial: 2000

Resultados da Pesquisa

Agora exibindo 1 - 3 de 3
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    Improved pectinase production in Penicillium griseoroseum recombinant strains
    (Journal of Applied Microbiology, 2011-06-27) Teixeira, J.A.; Gonçalves, D.B.; Queiroz, M.V. de; Araújo, E.F. de
    To obtain recombinant strains of Penicillium griseoroseum that produce high levels of pectin lyase (PL) and polygalacturonase (PG) simultaneously. A strain with high production of PL was transformed with the plasmid pAN52pgg2, containing the gene encoding PG of P. griseoroseum, under control of the gpd promoter gene from Aspergillus nidulans. Southern blot analysis demonstrated that all strain had at least one copy of pAN52pgg2 integrated into the genome. The recombinant strain P. griseoroseum T20 produced levels of PL and PG that were 266‐ and 27‐fold greater, respectively, than the wild‐type strain. Furthermore, the extracellular protein profile of recombinant T20 showed two protein bands of c. 36 and 38 kDa, associated with PL and PG, respectively. This recombinant strain T20 produces PL and PG using carbon sources of low costs, and an enzyme preparation that is free of cellulolytic and proteolytic activities. PL and PG play an important role in the degradation of pectin. Owing to their use in the juice and wines industries, there is a growing interest in the inexpensive production of these enzymes. This work describes an efficient system of protein expression and secretion using the fungus P. griseoroseum.
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    High genetic variability in endophytic fungi from the genus Diaporthe isolated from common bean (Phaseolus vulgaris L.) in Brazil
    (Journal of Applied Microbiology, 2015-11-06) Santos, T.T. dos; Souza Leite, T. de; Queiroz, C.B. de; Araújo, E.F. de; Pereira, O.L.; Queiroz, M.V. de
    The goals of the present study were to identify, to analyse the phylogenetic relations and to evaluate the genetic variability in Diaporthe endophytic isolates from common bean. Diaporthe sp., D. infecunda and D. phaseolorum strains were identified using multilocus phylogeny (rDNA ITS region; EF1‐α, β‐tubulin, and calmodulin genes). IRAP (Inter‐Retrotransposon Amplified Polymorphism) and REMAP (Retrotransposon‐Microsatellite Amplified Polymorphism) molecular markers reveal the existence of high genetic variability, especially among D. infecunda isolates. It was concluded that the multilocus phylogenetic approach was more effective than individual analysis of ITS sequences, in identifying the isolates to species level, and that IRAP and REMAP markers can be used for studying the genetic variability in the genus Diaporthe particularly at the intraspecific level. The combined use of molecular tools such as multilocus phylogenetic approach and molecular markers, as performed in this study, is the best way to distinguish endophytic strains of Diaporthe isolated from common bean (Phaseolus vulgaris L.).
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    Differential expression of plg genes from Penicillium griseoroseum: plg1 a pectinolytic gene is expressed in sucrose and yeast extract
    (Journal of Applied Microbiology, 2008-04-22) Bazzolli, D.M.S.; Ribon, A. de O.B.; Reis, K.C.P.; Queiroz, M.V. de; Araújo, E.F. de
    To study the regulation of the plg1 and plg2 genes of Penicillium griseoroseum, in order to identify the industrial potential of their products in alternative carbon sources that are cheaper and widely available in Brazil. RT-PCR and Northern blot were used to investigate if plg1 and plg2 expression is under influence of catabolic repression, ambient pH and cAMP. Results demonstrated that the genes were differentially regulated depending on the carbon sources in the culture medium and pH. Sucrose, a noninducing carbon source of the pectinolytic system, was able to promote plg1 transcription but only when yeast extract was added into the culture medium. The plg genes are differentially expressed. The plg1 gene is more attractive for industrial use due to its expression in alternative carbon sources like sucrose and yeast extract. In recent years, industries have been trying to replace the toxic conventional treatments employed in these processes by more eco-friendly enzyme treatment. Alternative carbon sources will be tested with the aim to reduce the costs associated to pectin lyase production in Brazil.