Microbiologia
URI permanente desta comunidadehttps://locus.ufv.br/handle/123456789/11840
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Item Occurrence and types of ectomycorrhizae present in seedlings of Picea glehnii in a natural forest in Hokkaido(Mycoscience, 1995-10) Kasuya, Maria Catarina Megumi; Igarashi, Tsuneo; Masato ShibuyaPicea glehnii seedlings whose ages ranged from 2 to 5 years and which were growing in aP. glehnii-Abies sachalinensis natural forest where the surface had been scarified 6 years before, were assessed for the occurrence and types of ectomycorrhizae. Based on the macro- and microscopic characteristics, 34 types of ectomycorrhizae were classified. The basidiomycetes were clearly dominant and it was common to observe more than one type of mycorrhiza occurring in the same root tip. The diversity of mycorrhizal types and the presence of at least one type of ectomycorrhiza in a single seedling, observed in this work, indicate a very dynamic system of mycorrhizal formation inP. glehnii seedlings, which allows them to survive and grow in a forest surface subjected to soil scarification.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 Fermentation of maltose and starch by Klebsiella oxytoca P2(Biotechnology Letters, 1998-12) Santos, Vera L. dos; Guimarães, Walter V.; Barros, Everaldo G. de; Araújo, Elza F.Klebsiella oxytoca P2, which has genes from Zymomonas mobilis encoding the alcohol dehydrogenase and pyruvate decarboxylase integrated in its chromosome, fermented 50 g maltose/l to 25.4 g of ethanol/l. It also fermented 10, 20 and 40 g starch/l yielding 4, 8.4, and 17.7 g ethanol/l, respectively, representing 72, 75 and 78% of the theoretical yield.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.Item Estudo da atividade antibacteriana de plantas medicinais, aromáticas e corantes naturais(Revista Brasileira de Farmacognosia, 1998) Bara, Maria Teresa Freitas; Vanetti, Maria Cristina DantasO emprego de recursos naturais como mecanismo auxiliar no tratamento de distintas patologias tem ressurgido, com ênfase, nos útimos tempos. Tendo em vista esta situação, este estudo teve por finalidade investigar a atividade antimicrobiana de algumas plantas medicinais e aromáticas bastantes comuns na cultura brasileira. Foi constatado que, de modo particular, o alecrim-pimenta (Lippia sidoides) levou a uma considerável inibição do crescimento bacteriano. Tambêm plantas como alecrim (Rosmarinus officinalis), cravo (Sysygium aromaticum), noz-moscada (Myristica fragrans), pimenta-da-jamaica (Pimenta dioica) e sálvia (Salvia officinalis) demonstraram constituir fontes eficientes de compostos bioativos antibacterianos.Item Variação sazonal da colonização de raízes de clones de híbridos de eucalipto por fungos micorrízicos no estado do Espírito Santo(Revista Brasileira de Ciência do Solo, 1998-07) Grazziotti, P. H.; Barros, N. F.; Borges, A. C.; Neves, J. C. L.; Fonseca, S.A colonização de raízes de clones de três híbridos de Eucalyptus grandis x E. urophylla por fungos micorrízicos foi estudada no campo em diferentes condições de solo. A colonização por fungos ectomicorrízicos e micorrízicos arbusculares foi avaliada em três locais do Espírito Santo, em quatro épocas de amostragem (julho e outubro de 1992 e janeiro e abril de 1993). A unidade experimental foi constituída por três árvores com cinco anos de idade. A colonização micorrízica mostrou-se dependente da área, da época de amostragem e dos clones. A ocorrência de ectomicorrizas foi maior no verão, quando se registraram as maiores temperaturas. A intensidade de colonização por fungos micorrízicos arbusculares foi semelhante entre as áreas e não apresentou variação consistente em função da época. O número de esporos de fungos micorrízicos arbusculares por grama de solo variou de acordo com a área e época de amostragem.Item Characterization of an Aspergillus nidulans mutant with abnormal distribution of nuclei in hyphae, metulae, phialides and conidia(FEMS Microbiology Letters, 1998-07-10) Queiroz, Marisa Vieira de; Azevedo, João Lúcio deThe V10 deteriorated variant of Aspergillus nidulans has hyphae, metulae, phialides and conidia with abnormal nuclear distributions. The alterations observed were: increase in the number of nuclei in hyphae, metulae and phialides, presence of anucleate, uninucleate and multinucleate conidia, abnormal vegetative growth and defective conidiation. When 0.5 M NaCl was added to the medium, an increase in the number of conidia was observed but their morphology and number of nuclei were not modified. The gene responsible for these alterations was named anuA1. The anuA1 gene is located on linkage group VII and is possibly involved in nuclear migration to hyphae, metulae, phialides and conidia. z 1998 Federation of European Microbiological Societies