Microbiologia
URI permanente desta comunidadehttps://locus.ufv.br/handle/123456789/11840
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Resultados da Pesquisa
Item Cloning and characterization of a gene encoding the endopolygalacturonase of Penicillium griseoroseum(Biotechnology Letters, 1999-05) Ribon, A. O. B.; Coelho, J. L. C.; Barros, E. G. de; Araújo, E. F.A conserved region of a polygalacturonase (PG) gene from Penicillium griseoroseum was PCR amplified and used to screen a genomic library from this fungus. The nucleotide sequence of the isolated clone (pggI) consisted of 1497 bp, including a coding region of 1251 bp. This region potentially encodes a protein of 376 amino acids, and is interrupted by two introns. Extensive homology was observed between this protein and several fungal endopolygalacturonases. DNA hybridization analyses revealed that there is a low copy number of pggI in the P. griseoroseum genome, probably one or two copies.Item Genetic diversity of the ectomycorrhizal fungus Pisolithus tinctorius based on RAPD-PCR analysis(Mycorrhiza, 1997-10-03) Junghans, D. T.; Gomes, E. A.; Guimarães, W. V.; Barros, E. G.; Araújo, E. F.Twenty Pisolithus tinctorius isolates from different geographic locations and different hosts were characterized by the random amplified polymorphic DNA technique. Thirteen arbitrary primers generated 87 DNA fragments, all of them polymorphic. These data were used to calculate genetic distances among the isolates. The pairwise genetic distances ranged from 1 to 100%, with an average of 58.7%. Cluster analysis based on the amplified fragments grouped the isolates according to their host and geographical origins. Group I contained isolates collected in Brazil and group II those collected in the Northern Hemisphere. In addition to the diversity seen at the molecular level, the isolates also showed host specificity. Greenhouse experiments demonstrated that isolates from the Northern Hemisphere colonized mainly Pinus whereas isolates from Brazil colonized only Eucalyptus. The molecular data suggest that the Pisolithus tinctorius isolates analyzed belong to two distinct groups. The data also suggest new guidelines for future investigations on the taxonomy and systematic of this important fungus species. Furthermore, these results support future experiments aimed at the selection and development of improved isolates of P. tinctorius.Item Production of pectin lyase by Penicillium griseoroseum as a function of the inoculum and culture conditions(World Journal of Microbiology and Biotechnology, 1992-10-09) Brumano, M. H. N.; Coelho, J. L. C.; Araújo, E. F.; Silva, D. O.Optimum activity of an extracellular pectin lyase produced by Penicillium griseoroseum in submerged culture was after 120 h using 0.1% (w/v) citrus pectin as substrate. Sucrose at 0.1% (w/v) stimulated enzyme production and citrus pectin gave the highest activity of enzyme per unit growth.Item Production and regeneration of protoplasts from the mycorrhizal fungus Suillus granulatus(World Journal of Microbiology and Biotechnology, 1996-04-11) Dias, E. S.; Araújo, E. F.; Guimarães, W. V.; Muchovej, R. M. C.Experiments were performed with the mycorrhizal fungus Suillus granulatus to define the parameters for production and regeneration of protoplasts. Protoplasts were released at frequencies between 1 and 3×107/ml from mycelium 3 to 7 days old. The best osmotic stabilizer for protoplast release was MgSO4 (0.7 m). To optimize protoplast release and regeneration an enzyme (Novozym 234) concentration 1.7 mg/ml was chosen, with a digestion time of 1 to 2 h. Regenerated colonies formed mycorrhizae within 60 days after inoculation in Pinus caribaea var. hondurensis seedlings.