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| Registros recuperados: 12 | |
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| Thimoteo,S.S.; Glogauer,A.; Faoro,H.; de Souza,E.M.; Huergo,L.F.; Moerschbacher,B.M.; Pedrosa,F.O.. |
| Chitinases are hydrolases that degrade chitin, a polymer of N-acetylglucosamine linked β(1-4) present in the exoskeleton of crustaceans, insects, nematodes and fungal cell walls. A metagenome fosmid library from a wastewater-contaminated soil was functionally screened for chitinase activity leading to the isolation and identification of a chitinase gene named metachi18A. The metachi18A gene was subcloned and overexpressed in Escherichia coli BL21 and the MetaChi18A chitinase was purified by affinity chromatography as a 6xHis-tagged fusion protein. The MetaChi18A enzyme is a 92-kDa protein with a conserved active site domain of glycosyl hydrolases family 18. It hydrolyses colloidal chitin with an optimum pH of 5 and temperature of 50°C. Moreover, the enzyme... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Chitinase; Metagenomic; Aeromonas; Kinetics. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2017000100602 |
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| Alves,L.P.S.; Almeida,A.T.; Cruz,L.M.; Pedrosa,F.O.; de Souza,E.M.; Chubatsu,L.S.; Müller-Santos,M.; Valdameri,G.. |
| The conventional method for quantification of polyhydroxyalkanoates based on whole-cell methanolysis and gas chromatography (GC) is laborious and time-consuming. In this work, a method based on flow cytometry of Nile red stained bacterial cells was established to quantify poly-3-hydroxybutyrate (PHB) production by the diazotrophic and plant-associated bacteria, Herbaspirillum seropedicae and Azospirillum brasilense. The method consists of three steps: i) cell permeabilization, ii) Nile red staining, and iii) analysis by flow cytometry. The method was optimized step-by-step and can be carried out in less than 5 min. The final results indicated a high correlation coefficient (R2=0.99) compared to a standard method based on methanolysis and GC. This method... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Flow cytometry; Nile red; Poly-3-hydroxybutyrate; Herbaspirillum seropedicae; Azospirillum brasilense. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2017000100606 |
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| Araújo,L.M.; Huergo,L.F.; Invitti,A.L.; Gimenes,C.I.; Bonatto,A.C.; Monteiro,R.A.; Souza,E.M.; Pedrosa,F.O.; Chubatsu,L.S.. |
| Azospirillum brasilense is a diazotroph found in association with important agricultural crops. In this organism, the regulation of nitrogen fixation by ammonium ions involves several proteins including the uridylyltransferase/uridylyl-removing enzyme, GlnD, which reversibly uridylylates the two PII proteins, GlnB and GlnZ, in response to the concentration of ammonium ions. In the present study, the uridylylation/deuridylylation cycle of A. brasilense GlnB and GlnZ proteins by GlnD was reconstituted in vitro using the purified proteins. The uridylylation assay was analyzed using non-denaturing polyacrylamide gel electrophoresis and fluorescent protein detection. Our results show that the purified A. brasilense GlnB and GlnZ proteins were uridylylated by... |
| Tipo: Info:eu-repo/semantics/other |
Palavras-chave: Azospirillum brasilense; Nitrogen fixation; PII-like protein; GlnD; GlnB; GlnZ. |
| Ano: 2008 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2008000400006 |
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| Pisa,G.; Magnani,G.S.; Weber,H.; Souza,E.M.; Faoro,H.; Monteiro,R.A.; Daros,E.; Baura,V.; Bespalhok,J.P.; Pedrosa,F.O.; Cruz,L.M.. |
| Sugarcane is an important agricultural product of Brazil, with a total production of more than 500 million tons. Knowledge of the bacterial community associated with agricultural crops and the soil status is a decisive step towards understanding how microorganisms influence crop productivity. However, most studies aim to isolate endophytic or rhizosphere bacteria associated with the plant by culture-dependent approaches. Culture-independent approaches allow a more comprehensive view of entire bacterial communities in the environment. In the present study, we have used this approach to assess the bacterial community in the rhizosphere soil of sugarcane at different times and under different nitrogen fertilization conditions. At the high taxonomic level, few... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: 16S rRNA; Biodiversity; Nitrogen fixation; Bacteria; Sugarcane; Soil. |
| Ano: 2011 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2011001200004 |
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| Sotomaior,P.; Araújo,L.M.; Nishikawa,C.Y.; Huergo,L.F.; Monteiro,R.A.; Pedrosa,F.O.; Chubatsu,L.S.; Souza,E.M.. |
| Azospirillum brasilense is a diazotroph that associates with important agricultural crops and thus has potential to be a nitrogen biofertilizer. The A. brasilense transcription regulator NifA, which seems to be constitutively expressed, activates the transcription of nitrogen fixation genes. It has been suggested that the nitrogen status-signaling protein GlnB regulates NifA activity by direct interaction with the NifA N-terminal GAF domain, preventing the inhibitory effect of this domain under conditions of nitrogen fixation. In the present study, we show that an N-terminal truncated form of NifA no longer required GlnB for activity and lost regulation by ammonium. On the other hand, in trans co-expression of the N-terminal GAF domain inhibited the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Azospirillum brasilense; NifA protein; GlnB protein; GAF domain; Nitrogen fixation. |
| Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2012001200005 |
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| Aquino,B.; Stefanello,A.A.; Oliveira,M.A.S.; Pedrosa,F.O.; Souza,E.M.; Monteiro,R.A.; Chubatsu,L.S.. |
| NifA is the transcriptional activator of the nif genes in Proteobacteria. It is usually regulated by nitrogen and oxygen, allowing biological nitrogen fixation to occur under appropriate conditions. NifA proteins have a typical three-domain structure, including a regulatory N-terminal GAF domain, which is involved in control by fixed nitrogen and not strictly required for activity, a catalytic AAA+ central domain, which catalyzes open complex formation, and a C-terminal domain involved in DNA-binding. In Herbaspirillum seropedicae, a β-proteobacterium capable of colonizing Graminae of agricultural importance, NifA regulation by ammonium involves its N-terminal GAF domain and the signal transduction protein GlnK. When the GAF domain is removed, the protein... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Biological nitrogen fixation; Herbaspirillum seropedicae; NifA. |
| Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2015000800683 |
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| Schmidt,M.A.; Souza,E.M.; Baura,V.; Wassem,R.; Yates,M.G.; Pedrosa,F.O.; Monteiro,R.A.. |
| Herbaspirillum seropedicae is an endophytic diazotrophic bacterium, which associates with important agricultural plants. In the present study, we have investigated the attachment to and internal colonization of Phaseolus vulgaris roots by the H. seropedicae wild-type strain SMR1 and by a strain of H. seropedicae expressing a red fluorescent protein (DsRed) to track the bacterium in the plant tissues. Two-day-old P. vulgaris roots were incubated at 30°C for 15 min with 6 x 10(8) CFU/mL H. seropedicae SMR1 or RAM4. Three days after inoculation, 4 x 10(4) cells of endophytic H. seropedicae SMR1 were recovered per gram of fresh root, and 9 days after inoculation the number of endophytes increased to 4 x 10(6) CFU/g. The identity of the recovered bacteria was... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Herbaspirillum seropedicae; Phaseolus vulgaris; Confocal microscopy. |
| Ano: 2011 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2011000300001 |
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| Nishikawa,C.Y.; Araújo,L.M.; Kadowaki,M.A.S.; Monteiro,R.A.; Steffens,M.B.R.; Pedrosa,F.O.; Souza,E.M.; Chubatsu,L.S.. |
| Azospirillum brasilense is a nitrogen-fixing bacterium associated with important agricultural crops such as rice, wheat and maize. The expression of genes responsible for nitrogen fixation (nif genes) in this bacterium is dependent on the transcriptional activator NifA. This protein contains three structural domains: the N-terminal domain is responsible for the negative control by fixed nitrogen; the central domain interacts with the RNA polymerase σ54 co-factor and the C-terminal domain is involved in DNA binding. The central and C-terminal domains are linked by the interdomain linker (IDL). A conserved four-cysteine motif encompassing the end of the central domain and the IDL is probably involved in the oxygen-sensitivity of NifA. In the present study,... |
| Tipo: Info:eu-repo/semantics/other |
Palavras-chave: Biological nitrogen fixation; Azospirillum brasilense; NifA protein. |
| Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2012000200004 |
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| Ishida,M.L.; Assumpção,M.C.; Machado,H.B.; Benelli,E.M.; Souza,E.M.; Pedrosa,F.O.. |
| Two Azospirillum brasilense open reading frames (ORFs) exhibited homology with the two-component NtrY/NtrX regulatory system from Azorhizobium caulinodans. These A. brasilense ORFs, located downstream to the nifR3ntrBC operon, were isolated, sequenced and characterized. The present study suggests that ORF1 and ORF2 correspond to the A. brasilense ntrY and ntrX genes, respectively. The amino acid sequences of A. brasilense NtrY and NtrX proteins showed high similarity to sensor/kinase and regulatory proteins, respectively. Analysis of lacZ transcriptional fusions by the ß-galactosidase assay in Escherichia coli ntrC mutants showed that the NtrY/NtrX proteins failed to activate transcription of the nifA promoter of A. brasilense. The ntrYX operon... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Azospirillum brasilense; Two-component regulatory system; Nitrogen regulation; NtrYX genes; NtrBC genes. |
| Ano: 2002 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2002000600004 |
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| Silva,J.L.C.; Barbosa,J.F.; Bravo,J.P.; Souza,E.M. de; Huergo,L.F.; Pedrosa,F.O.; Esteves,E.; Daffre,S.; Fernandez,M.A.. |
| Diatraea saccharalis (Fabricius, 1794) (Lepidoptera: Crambidae) is an important pest for Brazilian sugarcane. In the present study, we detected two distinct spots in hemolymph from septic injured larvae (HDs1 and HDs2), which are separated by 2DE gel electrophoresis. Both spots were subjected to in-gel tryptic digestion and MALDI-TOF/TOF analysis, which revealed the sequence VFGTLGSDDSGLFGK present in both HDs1 and HDs2. This sequence had homology and 80% identity with specific Lepidoptera antimicrobial peptides called gloverins. Analyses using the ImageMaster 2D software showed pI 8.94 of the HDs1 spot, which is similar to that described to Hyalophora gloveri gloverin (pI 8.5). Moreover, the 14-kDa molecular mass of the spot HDs1 is compatible to that of... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Diatraea saccharalis; Lepidoptera; Immune response; Gloverin; Sugarcane borer; Hemolymph. |
| Ano: 2010 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2010000500003 |
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| Portugal,M.E.G.; Souza,E.M.; Pedrosa,F.O.; Benelli,E.M.. |
| Streptococcus mutans is a Gram-positive bacterium present in the oral cavity, and is considered to be one of the leading causes of dental caries. S. mutans has a glnK gene, which codes for a PII-like protein that is possibly involved in the integration of carbon, nitrogen and energy metabolism in several organisms. To characterize the GlnK protein of S. mutans, the glnK gene was amplified by PCR, and cloned into the expression vectors pET29a(+) and pET28b(+). The native GlnK-Sm was purified by anion exchange (Q-Sepharose) and affinity (Hi-Trap Heparin) chromatography. The GlnK-His-Sm protein was purified using a Hi-Trap Chelating-Ni2+ column. The molecular mass of the GlnK-His-Sm proteins was 85 kDa as determined by gel filtration, indicating that this... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: GlnK; Streptococcus mutans; Nitrogen metabolism. |
| Ano: 2011 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2011000500003 |
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| Galvão,C.W.; Souza,E.M.; Etto,R.M.; Pedrosa,F.O.; Chubatsu,L.S.; Yates,M.G.; Schumacher,J.; Buck,M.; Steffens,M.B.R.. |
| DNA repair is crucial to the survival of all organisms. The bacterial RecA protein is a central component in the SOS response and in recombinational and SOS DNA repairs. The RecX protein has been characterized as a negative modulator of RecA activity in many bacteria. The recA and recX genes of Herbaspirillum seropedicae constitute a single operon, and evidence suggests that RecX participates in SOS repair. In the present study, we show that the H. seropedicae RecX protein (RecX Hs) can interact with the H. seropedicaeRecA protein (RecA Hs) and that RecA Hs possesses ATP binding, ATP hydrolyzing and DNA strand exchange activities. RecX Hs inhibited 90% of the RecA Hs DNA strand exchange activity even when present in a 50-fold lower molar concentration than... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: RecA; RecX; Herbaspirillum seropedicae; SOS repair. |
| Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2012001200004 |
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| Registros recuperados: 12 | |
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