Dynamics of Nitrite Content in Fresh Spinach Leaves: Evidence for Nitrite Formation Caused by Microbial Nitrate Reductase Activity

Watanabe, Naoko S.; Yamasaki, Hideo

doi:10.4172/2155-9600.1000572

Cited by 4 publications

(7 citation statements)

References 56 publications

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“…However, these results cannot exclude the role of bacteria that were initially present in these vegetables as they were deactivated as well by boiling. Recent report from Watanabe's lab showed the evidence of microbial NR involved in the formation of nitrite in spinach leaves during storage [8].…”

Section: Resultsmentioning

confidence: 99%

“…The intake of excess amount of nitrite is believed to cause increased risk of some cancers and methemoglobinemia in infants [6,7]. There are many reports on the nitrate and nitrite contents in retail leave vegetables [2,8,9]. In respect to nitrate and nitrite contents change in leave vegetables during storage, there are inconsistent and controversial results; some reports indicated that nitrate levels dropped and nitrite levels increased dramatically in leave vegetables during storage in a few days at ambient temperature, but nitrate and nitrite levels did not change significantly over 7 days of storage in a refrigerator [10,11]; some researchers reported that the nitrite content in spinach increased about 27% after being frozen for 6 months at -25°C while no significant change in nitrate content [12].…”

Section: Introductionmentioning

confidence: 99%

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Cabbage Inhibits Nitrite Formation In Other Vegetable Juices During Storage

Huang¹,

Robinson²,

Callaway³

et al. 2018

J Nutr Food Sci

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Although it is well known that green vegetables contain high content of nitrate, reported results regarding nitrite accumulation in fresh green vegetables are controversial. Recent studies suggest that nitrate from food has health benefits including reduce blood pressure and increase blood flow. Intake excess amount of nitrite is believed to cause increased risk of some cancers and methemoglobinemia in infants. In this study, we investigated the dynamics of nitrite and nitrate contents in spinach juice, iceberg lettuce juice, celery juice, green cabbage juice, and red cabbage juice. Nitrite concentration increased significantly in home-made spinach juice, iceberg lettuce juice, and celery juice after only two days of cold storage at 4°C; while nitrate concentrations in these vegetable juices decreased significantly with time during the storage, suggesting a conversion from nitrate to nitrite. However, no significant change in nitrite and nitrate concentrations observed in green cabbage juice and red cabbage juice during the storage. We further discovered that both green cabbage juice and red cabbage juice can completely inhibit the formation of nitrite in spinach juice, iceberg lettuce juice, and celery juice during cold storage at 4°C. Sodium tungstate, an inhibitor of nitrate reductase, was effective in inhibiting nitrite formation in celery juice during storage. The nitrite formation in these vegetable juices was much faster during storage at ambient temperature. The ability of cabbage to inhibit the formation of nitrite in other vegetable juice was also observed during storage at ambient temperature. However, if cabbage juice was boiled for five minutes prior to mixing with other vegetable juice then no inhibitory effect was observed. Cabbage had an inhibitory effect on nitrite formation when mixed with other vegetable juice. This effect was lost upon boiling, suggesting that cabbage may contain some compounds that can inhibit nitrate reductase that was decomposed by boiling.Note: a Nitrite concentrations were measured by the Griess assay, detection limit was 0.023 mg.l -1 . b Celery juice mixed with DI H 2 O (volume ratio 1:1) was set as a control sample. c Nitrite concentration in celery juice mixed with DI H 2 O increased significantly in two days, p<0.05. Table 5: The effect of nitrate reductase inhibitor (1 mM Na 2 WO 4 ) on the formation of nitrite in home-made celery juices during storage at 4 ± 1°C (n=5).

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Cabbage Inhibits Nitrite Formation In Other Vegetable Juices During Storage

Huang¹,

Robinson²,

Callaway³

et al. 2018

J Nutr Food Sci

View full text Add to dashboard Cite

show abstract

“…Roots are the rst places where nutrients are absorbed and translocated into shoots for chlorophyll synthesis. More root formation depends on several factors (Watanabe and Yamasaki, 2016;Goltsev et al, 2016). Response to limiting mineral elements, plants have the ability to allocate a greater proportion of their biomass to the root system (Slavin and Lloyd, 2012).…”

Section: Discussionmentioning

confidence: 99%

“…Many crop plants, especially leafy vegetables, accumulate excessive nitrate in expanded leaves under low light conditions when the uptake of nitrate exceeds reduction at a high transpiration rate. Usually when the plants use the solar energy su ciently, the absorbed nitrate from the soil is reduced to nitrite by Nitrate Reductase (NR) in cytosol (Watanabe and Yamasaki, 2016). Nitrite translocated into the chloroplasts is converted to ammonium ion (NH 4 + ) by nitrite reductase (NiR) located in the chloroplasts and then ammonium ion is assimilated into amino acids (Watanabe and Yamasaki, 2016).…”

Section: Introductionmentioning

confidence: 99%

Physio-Morphological Traits Contributing to Genotypic Differences in Nitrogen Use Efficiency of Leafy Vegetable Species under Hydroponics

Ulas

2023

Preprint

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Soil fertility is declining in low-input agriculture due to insufficient fertilizer application by small-scale farmers. On the other hand, the concerns are rising on environmental pollution of both air and water in high-input agriculture due to excessive use of N fertilizer in a short growing season of vegetable crops, which is directly linked with the health of human beings and environmental safety. The aim of the study was to determine genotypic differences in Nitrogen Use Efficiency (NUE) of different leafy vegetable species (Arugula, Spinach, Cress, Parsley and Dill) grown hydroponically under two different N-rates (Low N: 0.3 mM and High N: 3.0 mM) and to identify the plant traits which are contributing to NUE. The nutrient solution experiment was conducted between March – April in 2020 by using an aerated Deep-Water Culture (DWC) technique in a fully automated climate room with a completely randomized block design (CRBD) with three replications for five weeks. The results indicated that shoot growth, root morphological and leaf physiological responses were significantly (p<0.001) affected by Genotype, N-Rate and Genotype x N-Rate interaction. Shoot growth of some vegetable species (Argula, Spinach and Cress) was significantly higher under low N than high N-rate, illustrating that they have a great capability for NUE under low N stress conditions. Similar results were also recorded for the root growth of the N-efficient species under low N-rate. The NUE of these species was closely associated with leaf physiological (leaf area, SPAD, photosynthesis, leaf chlorophyll (a+b) and carotenoid) and root morphological (root length, root volume and average rot diameter) characteristics. These physiological and morphological plant traits could be useful characters for the selection and breeding of ‘N-efficient’ leafy vegetable species for sustainable agriculture in the future. However, further investigation should be carried out at field level to confirm their commercial production.

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“…NO is involved in this global cycle through the denitrification activities of soil bacteria. Both denitrifying and nitrifying bacteria produce inorganic nitrite (NO 2 − ) as an intermediate metabolite [ 124 , 125 , 126 ]. NO 3 − is absorbed by the roots, followed by being delivered to the green leaves where photosynthetic CO 2 assimilation takes place.…”

Section: Figurementioning

confidence: 99%

Pleiotropic Functions of Nitric Oxide Produced by Ascorbate for the Prevention and Mitigation of COVID-19: A Revaluation of Pauling’s Vitamin C Therapy

et al. 2023

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Linus Pauling, who was awarded the Nobel Prize in Chemistry, suggested that a high dose of vitamin C (L-ascorbic acid) might work as a prevention or treatment for the common cold. Vitamin C therapy was tested in clinical trials, but clear evidence was not found at that time. Although Pauling’s proposal has been strongly criticized for a long time, vitamin C therapy has continued to be tested as a treatment for a variety of diseases, including coronavirus infectious disease 2019 (COVID-19). The pathogen of COVID-19, SARS-CoV-2, belongs to the β-coronavirus lineage, which includes human coronavirus, severe acute respiratory syndrome (SARS), and Middle East respiratory syndrome (MERS). This review intends to shed new light on vitamin C antiviral activity that may prevent SARS-CoV-2 infection through the chemical production of nitric oxide (NO). NO is a gaseous free radical that is largely produced by the enzyme NO synthase (NOS) in cells. NO produced by upper epidermal cells contributes to the inactivation of viruses and bacteria contained in air or aerosols. In addition to enzymatic production, NO can be generated by the chemical reduction of inorganic nitrite (NO2−), an alternative mechanism for NO production in living organisms. Dietary vitamin C, largely contained in fruits and vegetables, can reduce the nitrite in saliva to produce NO in the oral cavity when chewing foods. In the stomach, salivary nitrite can also be reduced to NO by vitamin C secreted from the epidermal cells of the stomach. The strong acidic pH of gastric juice facilitates the chemical reduction of salivary nitrite to produce NO. Vitamin C contributes in multiple ways to the host innate immune system as a first-line defense mechanism against pathogens. Highlighting chemical NO production by vitamin C, we suggest that controversies on the therapeutic effects of vitamin C in previous clinical trials may partly be due to less appreciation of the pleiotropic functions of vitamin C as a universal bioreductant.

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Dynamics of Nitrite Content in Fresh Spinach Leaves: Evidence for Nitrite Formation Caused by Microbial Nitrate Reductase Activity

Cited by 4 publications

References 56 publications

Cabbage Inhibits Nitrite Formation In Other Vegetable Juices During Storage

Cabbage Inhibits Nitrite Formation In Other Vegetable Juices During Storage

Physio-Morphological Traits Contributing to Genotypic Differences in Nitrogen Use Efficiency of Leafy Vegetable Species under Hydroponics

Pleiotropic Functions of Nitric Oxide Produced by Ascorbate for the Prevention and Mitigation of COVID-19: A Revaluation of Pauling’s Vitamin C Therapy

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