Gene/Protein Disease Symptom Drug Enzyme Compound
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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)

1. Nitrite and nitrate levels were measured in samples from ileostomy bags or stomal samples of thirty-one ileostomists (twenty-two ulcerative colitis, nine Crohn's disease), 14-16 h after ingestion of a conventional meal or a meal containing a high content of nitrite and nitrate. 2. Ileostomy samples were decolourized with barium chloride, sodium sulphate and charcoal. Nitrite was determined spectrophotometrically by the Griess reaction and nitrate determined as nitrite after reduction with nitrate reductase (EC 1.7.99.4) in the presence of sodium formate. The mean percentage recovery from twenty-six spiked samples was 101.9 (SE 3.5)% for nitrite and 82.9 (SE 3.3)% for nitrate. 3. Ileostomy bag samples were obtained in twenty-nine cases of which ten had measurable nitrite (median 0, range 0-20.7 nmol/g) on a conventional meal compared with twenty-three cases (median 7.2, range 0-31.1 nmol/g) on the test meal (P less than 0.01). Nitrate levels were measurable in sixteen (median 6.7, range 0-48.2 nmol/g) after a conventional meal compared with twenty-one (median 20.5, range 0-53.2 nmol/g) after the test meal (P less than 0.01). 4. Stomal fresh-catch samples were obtained in twenty-four cases: combined nitrate and nitrite was higher in eighteen, lower in four and unchanged in two subjects after the test meal (P less than 0.05). 5. The type of foodstuff ingested can significantly alter measurable levels of nitrite-nitrate in the distal ileum and is one factor determining nitrite-nitrate input into the proximal colon.
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PMID:Nitrite and nitrate levels in ileostomy effluent: effect of dietary change. 270 31

To accommodate fluctuating nutrient levels in the soil, plants modulate their metabolism and root development via signaling mechanisms that rapidly reprogram the plant transcriptome. In the case of nitrate, over 1,000 genes are induced or repressed within minutes of nitrate exposure. To identify cis-regulatory elements that mediate these responses, an enhancer screen was performed in transgenic Arabidopsis (Arabidopsis thaliana) plants. A 1.8-kb promoter fragment from the nitrate reductase gene NIA1 was identified that acts as a nitrate enhancer when fused to a 35S minimal promoter. Enhancer activity was localized to a 180-bp fragment, and this activity could be enhanced by the addition of a 131-bp fragment from the nitrite reductase promoter. A promoter construct containing the 180- and 131-bp fragments was also induced by nitrite and repressed by ammonium, indicating that it was responsive to multiple nitrogen signals. To identify specific regulatory elements within the 180-bp NIA1 fragment, a transient expression system using agroinfiltration of Nicotiana benthamiana was developed. Deletion analysis identified three elements corresponding to predicted binding motifs for homeodomain/E-box, Myb, and Alfin1 transcription factors. A fully active promoter showing nitrate and nitrite enhancer activity equivalent to that of the wild-type 180-bp fragment could be built from these three elements if the spacing between the homeodomain/E-box and Myb-Alfin1 sites was equivalent to that of the native promoter. These findings were validated in transgenic Arabidopsis plants and identify a cis-regulatory module containing three elements that comprise a nitrate enhancer in the NIA1 promoter.
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PMID:Multiple regulatory elements in the Arabidopsis NIA1 promoter act synergistically to form a nitrate enhancer. 2066 61