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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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