Modulation of nitrate reductase activity in rice seedlings under aluminium toxicity and water stress: role of osmolytes as enzyme protectant

It has been suggested that nitrate and nitrite may play a role in the etiology of human oral cancer. We investigated whether salivary nitrate and nitrite and the activity of nitrate reductase (NRase) may affect the risk of oral cancer in Egypt, an area with high levels of environmental nitrosating agents. Levels of salivary nitrite (8.3 ± 1.0 μg/ml) and nitrate (44 ± 3.7 μg/ml) and activity of NRase (74 ± 10 nmol/ml/min) were significantly (P< 0.05) higher in oral cancer patients (n= 42) compared to control Egyptian healthy individuals (n= 40, nitrite = 5.3 ± 0.3 μg/ml, nitrate = 27 ± 1.2 μg/ml, and NRase activity = 46 ± 4 nmol/ml/min). The adjusted odds ratio (OR) and the 95% confidence intervals (C.I.) for risk of oral cancer, categorized by the levels of salivary nitrate and nitrite and NRase activity, showed a higher cancer risk associated with nitrite > 7.5 μg/ml (OR: 3.0, C.I.: 1.0–9.3), nitrite > 40 μg/ml (OR: 4.3, C.I.: 1.4–13.3) and NRase activity > 50 nmol/ml/min (OR: 2.9, C.I.: 1.1–7.4). Our findings suggest that increased consumption of dietary nitrate and nitrite is associated with elevated levels of salivary nitrite. Together with the increased activity of salivary NRase, these observations may explain, at least in part, the role of nitrate and nitrite in the development of oral cancer in individuals from an area with a high burden ofN-nitroso precursors.

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A Study on the Etiological Factors of Bilharzial Bladder Cancer in Egypt. 6. The Possible Role of Urinary Bacteria

Tumori Journal ◽

10.1177/030089168206800105 ◽

1982 ◽

Vol 68 (1) ◽

pp. 23-28 ◽

Cited By ~ 3

Author(s):

Abdelbaset Anwer El-Aaser ◽

Mahmoud Mohamed El-Merzabani ◽

Nadia Ahmed Higgy ◽

Abdel E. El-Habet

Keyword(s):

Escherichia Coli ◽

Bladder Cancer ◽

Enzyme Activity ◽

Nitrate Reductase ◽

Bacterial Infection ◽

Schistosoma Haematobium ◽

Nitrate Reductase Activity ◽

Reductase Activity ◽

Glucuronidase Activity

A correlation was obtained between a positive nitrite test in urine and the severity of urinary bacterial infection. Bacteria isolated from the urine of bilharzial or bladder cancer patients were found to be rich in nitrate reductase activity. « Escherichia coli » was the most common microorganism isolated from these specimens. Urine and several urinary constituents activate bacterial nitrate reductase. β-Glucuronidase activity in the urine of patients with chronic « Schistosoma haematobium » infection and bladder cancer was measured and shown to be significantly greater than that of urine of normal control subjects. Urinary bacterial infection was shown to be the source of the increased urinary level of enzyme activity at pH 7.0.

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Nitrate reductase activity in Paul's scarlet rose suspension cultures and the differential role of nitrate and molybdenum in induction

Planta ◽

10.1007/bf00387887 ◽

1978 ◽

Vol 141 (2) ◽

pp. 183-189 ◽

Cited By ~ 11

Author(s):

R. W. Jones ◽

A. J. Abbott ◽

E. J. Hewitt ◽

G. R. Best ◽

E. F. Watson

Keyword(s):

Nitrate Reductase ◽

Nitrate Reductase Activity ◽

Reductase Activity ◽

Suspension Cultures

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The role of a novel cytochrome b-costaining nitrate reductase and quinone in the invitro reconstruction of formate-nitrate reductase activity of E. coli.

Biochemical and Biophysical Research Communications ◽

10.1016/s0006-291x(74)80416-x ◽

1974 ◽

Vol 61 (4) ◽

pp. 1234-1241 ◽

Cited By ~ 49

Author(s):

H.G. Enoch ◽

R.L. Lester

Keyword(s):

Nitrate Reductase ◽

Cytochrome B ◽

Nitrate Reductase Activity ◽

Reductase Activity ◽

E Coli

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Anatomic and physiological modifications in seedlings of Coffea arabica cultivar Siriema under drought conditions

Ciência e Agrotecnologia ◽

10.1590/s1413-70542014000100003 ◽

2014 ◽

Vol 38 (1) ◽

pp. 25-33 ◽

Cited By ~ 5

Author(s):

Emanuelle Ferreira Melo ◽

Christiane Noronha Fernandes-Brum ◽

Fabrício José Pereira ◽

Evaristo Mauro de Castro ◽

Antonio Chalfun-Júnior

Keyword(s):

Water Stress ◽

Nitrate Reductase ◽

Water Potential ◽

Nitrate Reductase Activity ◽

Stomatal Density ◽

Reductase Activity ◽

Stomatal Resistance ◽

Partial Recovery ◽

Worldwide Production ◽

Weather Changes

Due to the weather changes prognostic for the coming years, the understanding of water deficit and physiological responses of plants to drought becomes an important requirement in order to develop technologies such as mechanisms to assist plants to cope with longer drought periods, which will be essential to maintenance of Brazilian and worldwide production. This study aimed to evaluate ecophysiological and anatomical aspects as well as the nitrate reductase activity in Siriema coffee seedlings subjected to four treatments: Daily irrigated, non-irrigated, re-irrigated 24 hours and re-irrigated 48 hours after different stress periods. Non-irrigation promoted a reduction in leaf water potential being accented from the ninth day of evaluation onwards. Re-irrigation promoted a partial recovery of the plant water potential. Non-irrigated plants showed an increase in stomatal resistance and reduction of transpiration and nitrate reductase activity. In the roots, there was a decrease in nitrate reductase activity under water stress. Leaf anatomical modifications were significant only for the adaxial surface epidermis and palisade parenchyma thickness, this latter characteristic being higher in control plants. Stomatal density and polar and equatorial diameter ratios showed the highest values in plants under water stress. In the roots, differences only in the cortex thickness being bigger in the non-irrigated treatment could be observed. Therefore, Siriema coffee plants under water stress show physiological, biochemical and anatomical modifications that contribute to the tolerance of this genotype to these conditions.

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