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| Registros recuperados: 20 | |
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| Maccheroni Jr.,Walter; Araújo,Welington Luiz; Azevedo,João Lúcio. |
| In fungi a genetic system ensures that enzymes are secreted mainly at ambient pH values corresponding to their optima of activity. Although a great deal of information has been obtained concerning this environmental response, there is a lack of studies involving phytopathogenic, endophytic and entomopathogenic fungi as well as different aspects of fungus-host interactions. This study compares in a plate-clearing assays, the effect of ambient pH in the secretion of amylase, cellulase, lipase, pectinase and protease by endophytic, phytopathogenic, and entomopathogenic isolates belonging to several species of Colletotrichum. All enzymes were secreted in a pH-dependent manner by all isolates. Endophytes and pathogens showed distinct patterns of protease... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Glomerella; Enzyme secretion; Endophytes; Pathogenic fungi; PacC. |
| Ano: 2004 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162004000300010 |
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| Orlandelli,Ravely Casarotti; Almeida,Tiago Tognolli de; Alberto,Raiani Nascimento; Polonio,Julio Cesar; Azevedo,João Lúcio; Pamphile,João Alencar. |
| Endophytes are being considered for use in biological control, and the enzymes they secrete might facilitate their initial colonization of internal plant tissues and direct interactions with microbial pathogens. Microbial proteases are also biotechnologically important products employed in bioremediation processes, cosmetics, and the pharmaceutical, photographic and food industries. In the present study, we evaluated antagonism and competitive interactions between 98 fungal endophytes and Alternaria alternata, Colletotrichum sp., Phyllosticta citricarpa and Moniliophthora perniciosa. We also examined the proteolytic activities of endophytes grown in liquid medium and conducted cup plate assays. The results showed that certain strains in the assemblage of... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Antagonism; Competitive interaction; Dual culture; Cup plate; Protease. |
| Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822015000200359 |
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| Lacava,Paulo Teixeira; Andreote,Fernando Dini; Araújo,Welington Luiz; Azevedo,João Lúcio. |
| O objetivo deste trabalho foi caracterizar a comunidade bacteriana endofítica de plantas assintomáticas (escapes) e afetadas pela clorose variegada dos citros (CVC) por meio de isolamento em meio de cultura, técnica de gradiente desnaturante em gel de eletroforese (DGGE) e detecção de Methylobacterium mesophilicum e Xyllela fastidiosa por meio de PCR específico, para estudar esta comunidade e sua relação com a ocorrência da CVC. A análise da comunidade bacteriana via DGGE permitiu a detecção de X. fastidiosa, bem como Klebsiella sp. e Acinetobacter sp. como endófitos de citros. Foram observados também Curtobacterium sp., Pseudomonas sp., Enterobacter sp. e Bacillus spp. Utilizando primers específicos, Methylobacterium mesophilicum e X. fastidiosa também... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Citrus sinensis; Xylella fastidiosa; Methylobacterium; Bactérias endofíticas. |
| Ano: 2006 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2006000400013 |
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| Rudi Emerson de Lima,Procópio; Araújo,Welington Luiz; Andreote,Fernando Dini; Azevedo,João Lúcio. |
| A circular cryptic plasmid named pPAGA (2,734 bp) was isolated from Pantoea agglomerans strain EGE6 (an endophytic bacterial isolate from eucalyptus). Sequence analysis revealed that the plasmid has a G+C content of 51% and contains four potential ORFs, 238(A), 250(B), 131(C), and 129(D) amino acids in length without homology to known proteins. The shuttle vector pLGM1 was constructed by combining the pPAGA plasmid with pGFPmut3.0 (which harbors a gene encoding green fluorescent protein, GFP), and the resulting construct was used to over-express GFP in E. coli and P. agglomerans cells. GFP production was used to monitor the colonization of strain EGE6gfp in various plant tissues by fluorescence microscopy. Analysis of EGE6gfp colonization showed that 14... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Green fluorescent protein; Bacteria; Host plant; Eucalyptus. |
| Ano: 2011 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572011000100018 |
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| Lacava,Paulo Teixeira; Silva-Stenico,Maria Estela; Araújo,Welington Luiz; Simionato,Ana Valéria Colnaghi; Carrilho,Emanuel; Tsai,Siu Mui; Azevedo,João Lúcio. |
| The objective of this work was to study the production of siderophores by endophytic bacteria Methylobacterium spp., which occupy the same ecological niche as Xylella fastidiosa subsp. pauca (Xfp) in citrus plants. The siderophore production of Methylobacterium strains was tested according to chromeazurol agar assay test (CAS), Csáky test (hydroxamate-type) and Arnow test (catechol-type). In addition, the ability of Xfp to use siderophores, in vitro, produced by endophytic bacteria as source of iron, was evaluated. All 37 strains of Methylobacterium spp. tested were CAS-positive for siderophore production. Methylobacterium spp. produced hydroxamate-type, but not catechol-type siderophores. In vitro growth of Xfp was stimulated by the presence of... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Citrus variegated chlorosis; Endophytes; Heterologous siderophores; Iron; Symbionts. |
| Ano: 2008 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2008000400011 |
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| Queiroz,Marisa V. de; Pizzirani-Kleiner,Aline Aparecida; Azevedo,João Lúcio. |
| Pulsed-field gel electrophoresis was used to characterize strains of Aspergillus nidulans with a chromosomal duplication Dp(I-II). Morphologically deteriorated and improved variants of these strains were also analyzed. The electrophoretic karyotype demonstrated that in two duplicated strains (A and B) the 4.2 Mb band, which corresponds to chromosome II, was absent and a new band was observed. Hybridization studies using the uapA (chromosome I) and wA (chromosome II) genes demonstrated that the new band corresponded to chromosome II plus the duplicated segment of chromosome I. The size of the chromosomal duplication was approximately 1.0 Mb. Analysis of the chromosomal bands of a morphologically improved strain showed that the duplicated segment of... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 2000 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572000000200009 |
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| Azevedo,João Lúcio; Maccheroni Jr.,Walter; Pereira,José Odair; de Araújo,Welington Luiz. |
| In the past two decades, a great deal of information on the role of endophytic microorganisms in nature has been collected. The capability of colonizing internal host tissues has made endophytes valuable for agriculture as a tool to improve crop performance. In this review, we addressed the major topics concerning the control of insects-pests by endophytic microorganisms. Several examples of insect control are described, notably those involving the interactions between fungi and grazing grasses from temperate countries. The mechanisms by which endophytic fungi control insect attacks are listed and include toxin production as well as the influence of these compounds on plant and livestock and how their production may be affected by genetic and environmental... |
| Tipo: Journal article |
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| Ano: 2000 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582000000100004 |
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| Glienke-Blanco,Chirlei; Aguilar-Vildoso,Carlos Ivan; Vieira,Maria Lúcia Carneiro; Barroso,Paulo Augusto Vianna; Azevedo,João Lúcio. |
| During some phases of of their life-cycle endophytic fungi colonize plants asymptomatically being found most frequently inside the aerial part of plant tissues. After surface disinfection of apparently healthy leaves from three varieties of mandarin orange and one tangor, and after incubation on appropriate culture medium, 407 fungal isolates were obtained, giving a total infection frequency of 81%. No fungal growth was observed from disinfected seeds, indicating that fungi are probably not transmitted via seeds. Of the fungal isolates, 27% belonged to the genus Guignardia, with 12 isolates being identified as Guignardia citricarpa Kiely, which is described as a citrus pathogen. The isolates were variable in respect to the presence of sexual structures and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Citrus; Endophytes; Genetic variability; Guignardia citricarpa; Mandarin; RAPD. |
| Ano: 2002 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572002000200021 |
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| Pimentel,Ida Chapaval; Glienke-Blanco,Chirlei; Gabardo,Juarez; Stuart,Rodrigo Makowiecky; Azevedo,João Lúcio. |
| A total of 297 endophytic fungi were isolated from 1728 leaf and stem fragments collected about twenty and forty days after germination from soybean (Glycine max (L.) Merril) plants grown in the field and a greenhouse. The fungi belonged to eight groups, six dematiaceous genera (Alternaria, Cladosporium, Chaetomium, Curvularia, Drechslera and Scopulariopsis) and the non-dematiaceous genera Acremonium, Aspergillus, Colletotrichum, Fusarium, Paecilomyces and Penicillium along with some Mycelia sterilia.. There were qualitative and quantitative differences in the type and number of isolates obtained from greenhouse and field-grown plants, with more isolates being obtained from the latter. No difference was found in the number of fungi isolated from leaves and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Endophytic fungi; Soybean; Biological control. |
| Ano: 2006 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132006000600003 |
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| Onofre,Sideney Becker; Riveros Gonzalez,Raul; Messias,Cláudio Luiz; Azevedo,João Lúcio; Barros,Neiva Monteiro de. |
| The entomopathogenic fungus Nomuraea rileyi (Farlow) Samson produced a peptide active against Anticarsia gemmatalis 3rd instar larvae. To produce this peptide, N. rileyi was cultivated aerobically in Saboraud, maltose, yeast-extract broth at 26 ± 1ºC for 12 days, after which the medium was filtered and separated in a liquid/liquid extractor, concentrated and the peptide purified chromatographically. The crystals obtained were kept refrigerated until needed for LC50 analysis. The LC50 of this peptide against A. gemmatalis 3rd instar larvae was determined in triplicate experiments using solutions containing 1.0, 0.2, 0.1, 0.01, 0.001 and 0.0001 mg/ml of N. rileyi peptide. The results of these experiments were used to calculate a linear equation in which Y =... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Anticarsia gemmatalis; Nomuraea rileyi; Integrated control; Secondary metabolite; Toxins. |
| Ano: 2002 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132002000300004 |
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| Specht,Alexandre; Azevedo,João Lúcio; Lima,Elza Áurea de Luna Alves; Boldo,Juliano Tomazzoni; Martins,Mayra Kassawara; Lorini,Lisete Maria; Barros,Neiva Monteiro. |
| Este fungo foi isolado pela primeira vez de lagartas de L. obliqua de uma agregação em plátano (Platanus acerifolia (Aiton) Wild - Platanaceae), em Bento Gonçalves, RS, Brasil. Após isolamento, purificação e caracterização, realizou-se um teste de patogenicidade com lagartas sadias de L. obliqua para corroborar, sua infectividade pelo postulado de Koch. Constatou-se correspondência morfológica e molecular entre o inóculo e o reisolado, comprovando sua patogenicidade a L. obliqua. |
| Tipo: Info:eu-repo/semantics/other |
Palavras-chave: Controle biológico; Inimigos naturais; Lagartas urticantes. |
| Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0085-56262009000300029 |
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| Martinati,Juliana Camargo; Lacava,Paulo Teixeira; Miyasawa,Sandra Kazue Shishido; Guzzo,Sylvia Dias; Azevedo,João Lúcio; Tsai,Siu Mui. |
| O objetivo deste trabalho foi avaliar o efeito da aplicação do benzotiadiazole (BTH) e do silício sobre o controle da doença causada pela Xylella fastidiosa subsp. pauca em Nicotiana tabacum. Os experimentos foram conduzidos em condições de casa de vegetação, onde as plantas de N. tabacum receberam inoculação de X. fastidiosa (linhagem 9a5c) com 4,7x10(7) UFC mL-1. Os tratamentos consistiram da pulverização das folhas, com soluções de BTH (0,6 e 1,2 mM), e aplicação ao solo de soluções de metassilicato de sódio (2 e 4 µM de Si). Cinco plantas foram utilizadas, por tratamento. Plantas de N. tabacum tratadas com BTH não demonstraram redução de sintomas da bacteriose. Entretanto, plantas tratadas com metassilicato de sódio, sim. A indução de resistência pelo... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Nicotiana tabacum; BTH; Indução de resistência sistêmica; Clorose variegada dos citros. |
| Ano: 2007 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2007000800004 |
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| Barros,Irene de Araújo; Araújo,Welington Luiz; Azevedo,João Lúcio. |
| Endophytic bacteria associated with the fern Dicksonia sellowiana were investigated. The bacterial communities from the surface-sterilized pinnae and rachis segments of the plants from the Brazilian Atlantic Rainforest that grew in native field conditions were compared with the bacterial communities from plants grown in greenhouses and plants that were initially grown in greenhouses and then transferred to the forest. From 540 pinnae and 540 rachis segments, 163 (30.2%) and 346 (64.2%) were colonized by bacteria, respectively. The main bacterial genera and species that were isolated included Bacillus spp. (B. cereus, B. megaterium, B. pumilus and B. subtilis), Paenibacillus sp., Amphibacillus sp., Gracilibacillus sp., Micrococcus sp. and Stenotrophomonas... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Brazilian Tropical forest; Ferns; 16S rDNA; Bacterial diversity; Bacillus. |
| Ano: 2010 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822010000400014 |
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| Registros recuperados: 20 | |
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