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Query: EC:1.7.1.2 (nitrate reductase)
 3,861 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The genes encoding membrane-bound nitrate reductase and its locus from Pseudomonas sp. strain MT-1, which is isolated from the sediment of Mariana Trench, were identified. To some extent, the gene organization in the cluster was different from those of other Pseudomonads. Quite interestingly, two genes encoding putative nitrate transporter (narK and narM) showed higher homologies to counterparts of organisms belonging to other genera than those of Pseudomonads. Especially, narM showed no significant homology to the genes for nitrate transporter of Pseudomonads, and was homologous to those of some marine bacteria. Further, arrangements of NarL- and Fnr-binding motifs in the cluster were different from those of P. stutzeri, closely related strain with MT-1. These observations clearly indicated that lateral transfer of genes in nar gene cluster had occurred in deep sea, and it may contribute to bacterial adaptation to environment of there.
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PMID:Lateral gene transfer in the deep sea of Mariana Trench: identification of nar gene cluster encoding membrane-bound nitrate reductase from Pseudomonas sp. strain MT-1. 1562 58

The nap gene cluster encoding periplasmic nitrate reductase was identified from Pseudomonas sp. strain MT-1, a deep-sea denitrifier isolated from the Mariana Trench. The ORFs identified were highly homologous with those of Pseudomonas stutzeri, but the cluster included only four ORFs (napDABC), less than those in other organisms. For other bacteria, some additional small ORFs (such as napE, napF, napG, napH, and napK) are found in the nap gene cluster, although their physiological function is still unclear. The soluble fraction of MT-1 grown under denitrifying condition showed significant nitrate reductase activity. This observation suggests that the periplasmic nitrate reductase encoded by the gene cluster identified in this study is functional. The activity was highest when the organism was grown under denitrifying conditions, suggesting that the enzyme participates in dissimilatory nitrite reduction.
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PMID:Identification of the functional periplasmic nitrate reductase (nap) gene cluster from the deep-sea denitrifier Pseudomonas sp. strain MT-1. 1769 Apr 69

The deep-sea denitrifier Pseudomonas sp. strain MT-1 has two distinct gene clusters encoding dissimilatory nitrate reductases, periplasmic nitrate reductase (Nap) and membrane-bound nitrate reductase (Nar). In order to investigate the physiological roles of these enzymes, we determined the nitrate reductase activity of the soluble and membrane fractions from MT-1 and the type strain of Pseudomonas stutzeri (closely related with MT-1) grown under various conditions. In MT-1, the activities of both fractions were highest when the cells were grown anaerobically in the presence of nitrate under atmospheric pressure. However, the activity of the soluble fraction decreased when the cells were grown under high pressure, whereas that of membrane fraction remained constant. Further, the activity of the soluble fraction decreased when the enzyme reaction was performed at low temperature, although that of membrane fraction was not similarly affected. Additionally, the results of RT-PCR showed that expression of the nar genes was strongly induced under high pressure. In contrast, P. stutzeri(T) showed no such response following a shift in growth pressure. These results suggest that MT-1 possesses a special mechanism for adaptation to the low-temperature and high-pressure environments of the deep sea, and that Nar is the main dissimilatory nitrate reductase in MT-1 in such environments.
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PMID:Physiological roles of two dissimilatory nitrate reductases in the deep-sea denitrifier Pseudomonas sp. strain MT-1. 1935 28

The deep-sea denitrifier Pseudomonas sp. MT-1 has two gene clusters encoding dissimilatory nitrate reductases, periplasmic nitrate reductase (Nap) and membrane-bound nitrate reductase (Nar). In order to investigate the physiological role of these enzymes, we constructed the disrupted mutants of napA, narG, and narK (encoding the catalytic subunits of Nap and Nar, as well as the nitrate transporter, respectively). The napA mutant showed almost the same growth rate as the wild-type under both atmospheric and high pressure of 30 MPa. On the other hand, the narG and narK mutants showed growth deficiencies under atmospheric pressure which were more pronounced at a pressure of 30 MPa. Thus, Nar was shown to be the dominant dissimilatory nitrate reductase in MT-1, especially under high pressure, whereas Nap can support the growth with denitrification to some extent. Further, nitrate reductase activity of the soluble and membrane fractions of MT-1 was measured under high pressure. Both activities were highly piezotolerant even under a pressure of 150 MPa. Therefore, the stability of nitrate reductases under high pressure is not a limiting step for the growth of MT-1 under these conditions. Although the reason why Nar rather than Nap is dominant and the physiological role of Nap in MT-1 are still unclear, we have demonstrated the mechanisms of the denitrification system in the environment of the deep-sea.
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PMID:Nar is the dominant dissimilatory nitrate reductase under high pressure conditions in the deep-sea denitrifier Pseudomonas sp. MT-1. 2637 35

In this paper, relative nitrate reductase activities of the soluble and membrane fractions of MT-1 grown anaerobically under atmospheric pressure in the presence of 30 mM NaNO3 were measured. In the analyses, the diazocoupling method was employed to determine the concentration of nitrite formed. Follow-up recent experiments have revealed that formed coupling compound lose its color rapidly, but this instability is unusual. The authors recognized the possibility that they failed to quantify the accurate concentration of nitrite formed and agree the additional in-depth analyses should be performed. Thus, the JGAM editorial board agreed to retract the paper.
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PMID:Nar is the dominant dissimilatory nitrate reductase under high pressure conditions in the deep-sea denitrifier Pseudomonas sp. MT-1. 2583 75