Arthur Fernandes Siqueira

Tohoku University | Tohokudai · Department of Environmental Life Sciences

N2O is an important greenhouse gas influencing global warming, and agricultural land is the predominant (anthropogenic) source of N2O emissions. Here, we report the high N2O-reducing activity of Bradyrhizobium ottawaense, suggesting the potential for efficiently mitigating N2O emission from agricultural lands. Among the 15 B. ottawaense isolates ex...

N 2 O is the major greenhouse gases influencing global warming, and agricultural land is the predominant (anthropogenic) source of N 2 O emissions. Here, we report the high N 2 O-reducing activity of Bradyrhizobium ottawaense , suggesting the potential for efficiently mitigating N 2 O emission from agricultural lands. Among the 15 B. ottawaense iso...

Soybean plants host endosymbiotic dinitrogen (N2)-fixing bacteria from the genus Bradyrhizobium. Under oxygen-limiting conditions, Bradyrhizobium diazoefficiens and Bradyrhizobium japonicum perform denitrification by sequentially reducing nitrate (NO3–) to nitrous oxide (N2O) or N2. The anaerobic reduction of NO3– to N2O was previously shown to be...

The soybean symbiont Bradyrhizobium diazoefficiens grows anaerobically in the presence of nitrate using the denitrification pathway, which involves the nap, nir, nor, and nos genes. We previously showed that NasT acts as a transcription antitermination regulator for nap and nos gene expression. In the present study, we investigated the targets of N...

When soil oxygen levels decrease, some bradyrhizobia use denitrification as an alternative form of respiration. Bradyrhizobium diazoefficiens (nos⁺) completely denitrifies nitrate (NO3–) to dinitrogen, whereas B. japonicum (nos–) is unable to reduce nitrous oxide to dinitrogen. We found that anaerobic growth with NO3– as the electron acceptor was s...

Background The soybean-Bradyrhizobium symbiosis can be highly efficient in fixing nitrogen, but few genomic sequences of elite inoculant strains are available. Here we contribute with information on the genomes of two commercial strains that are broadly applied to soybean crops in the tropics. B. japonicum CPAC 15 (=SEMIA 5079) is outstanding in it...

The 450-million-year-old interaction between the majority of land plants and mycorrhizal fungi is one of the most ancient, abundant, and ecologically important symbiosis on earth. The early events in the evolution of mycorrhizal symbioses seem to have involved reciprocal genetic changes in ancestral plants and free-living fungi. new data on the mec...

Utilização de enzimas do estresse oxidativo como biomarcadoras de impactos ambientais Using oxidative stress enzymes as biomarkers in environmental impacts Resumo O uso intensivo de compostos xenobióticos em atividades humanas é responsável pela contaminação de vários ambientes, provocando alterações em diferentes níveis ecológicos. O monitoramento...

Desvendando a H + -Pirofosfatase vacuolar e o seu papel na biotecnologia vegetal Unravelling the vacuolar H + -Pyrophosphatase and its role on plant biotechnology Resumo As proteínas de membrana são de fundamental importância para manter o funcionamento da célula e a homeostase iônica dos seres-vivos. Há uma diversidade de proteínas que ajudam a ma...

s) autor(es). Publicado pela ESFA. Queiroz S, Maximiniano A, Siqueira AF, Cruz ZMA & Ramos AC (2007) Parâmetros físico-químicos e microbiológicos do processo de atenuação natural monitorada em área contaminada por solventes clorados. Natureza on line 5(1): 10-18. [on line] http:

Resumo O uso intensivo de compostos xenobióticos em atividades humanas é responsável pela contaminação de vários ambientes, provocando alterações em diferentes níveis ecológicos. O monitoramento das possíveis consequências do uso indiscriminado desses compostos é realizado por intermédio de biomarcadores ou bioindicadores, principalmente em ambient...