The inducible formation of urease in rice plants

Matsumoto, Hisashi; Yasuda, Takeshi; Kobayashi, Maki; Takáhashi, Eiichi

doi:10.1080/00380768.1966.10431964

Cited by 22 publications

(13 citation statements)

References 26 publications

(15 reference statements)

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“…The apparent induction of nitrate reductase (7) and of nitrite reductase (14) by nitrate or nitrite, and the apparent derepression of acid phosphatase by the absence of phosphate (27) and of ATP sulfurylase by the absence of sulfur (22) have been documented in the XD cell line. It was anticipated that urea might similarly induce urease in these cells because of the previous reports of apparent induction of urease in other higher plant tissues (5,17,18,20), and because it can serve as an optional nitrogen source for growth of XD cells (4, 1 1) and other plant tissue cultures (4,12,20,29).…”

Section: Discussionmentioning

confidence: 99%

“…Therefore, it appears that the only mechanism by which higher plants utilize urea is hydrolysis by urease. Increases in urease activity in response to urea have been reported to occur in potato plants (18), rice plants (17), duckweed (5), and cell cultures of soybean (20). These increases occurred within a few hours to a few days after beginning the exposure to urea.…”

mentioning

confidence: 97%

“…On the other hand, urease activity has been detected in the tissues of numerous species of higher plants (3,5,9,17,20,29). Therefore, it appears that the only mechanism by which higher plants utilize urea is hydrolysis by urease.…”

mentioning

confidence: 99%

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Slow Adaptive Changes in Urease Levels of Tobacco Cells Cultured on Urea and Other Nitrogen Sources

Skokut¹,

Filner²

1980

Plant Physiol.

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MATERIALS AND METHODSGrowth Media. Medium M-ID, which contains 2.5 mm nitrate, and nitrate-free M-ID, in which equimolar amounts of the chlorides of K and Ca are substituted for the corresponding nitrates, were prepared as described previously (6, 7). Ammonium succinate M-ID was prepared by the addition of 3 mm ammonium chloride and 1.5 mm succinic acid to nitrate-free M-ID. Casamino acids M-ID was prepared by addition of 0.1% w/v casamino acids (Difco Laboratories, Detroit) to nitrate-free M-ID. Urea M-ID was prepared by addition of 0.3% (v/v) 1 M urea in water to nitrate-free M-ID. All media were autoclaved for 20 min, and the urea and casamino acids stock solutions were sterilized by filtration through a sterile membrane filter (type HA, 0.22 Am pore, Millipore Corp. The urea used was obtained from two sources.Urea from Fisher Scientific Co. was first purified by batchwise adsorption of anions on Bio-Rad AG 2-X8 ion exchange resin in the hydroxyl form. Urea (ultrapure grade) obtained from Schwarz/Mann was used without further purification. All media, and the urea and casamino acids stock solutions were adjusted with NaOH to pH 6.2 prior to sterilization.Growth of Cells. Cells of tobacco (Nicotiana tabacum L. cv. Xanthi, line XD) were grown on the various liquid media described above under the culture conditions described previously (6). Cultures were maintained by inoculating 500-ml portions of media with 25-ml aliquots of 12-to 14-day-old stationary phase cultures of cells grown on nitrate or of 14-to 18-day old stationary phase cultures of cells grown (more slowly) on urea. The fresh weights of inocula were 0.5-1 g/liter.Harvesting of Cells and Preparation of Extracts. Cells were harvested by vacuum filtration on Whatman No. I filter paper and rinsed with deionized distilled H20. After determining the fresh weight, the cells were suspended in ice-cold 50 mm Bicine3-NaOH (Sigma) (pH 7.2) containing 5 mm dithioerythritol (Sigma).

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 97%

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Slow Adaptive Changes in Urease Levels of Tobacco Cells Cultured on Urea and Other Nitrogen Sources

Skokut¹,

Filner²

1980

Plant Physiol.

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“…This pattern of rise and fall seems to be common in induced enzymes of plant materials, e.g. nitrate reductase (10) and urease (15,17,25).…”

Section: Methodsmentioning

confidence: 99%

Induction of Barley Leaf Urease

Chen¹,

Ching²

1988

Plant Physiol.

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Foliar urea application on barley plants increased leaf urease activity for 5 hours with a peak of 20-fold at 2 hours. To discern the mode of urease induction, urea with or without inhibitors and [35S]methionine were incubated with leaf sections for different lengths of time. Urease was extracted, partially purified, electrophoresed, and then quantified by fluorogram. Five urease (U) isozymes were separated by PAGE. Ua and Ub might be polymers or complexes that occurred only at the peak of induced activity. U, and U2 appeared at 0.5 and 0.75 hour, respectively, after urea induction, peaked at 2 hours, and persisted only in treated leaves for several additional hours indicating that they are transient inducible forms. U3 was the constitutive form present in control and treated leaves. Induction with cordycepin or cycloheximide completely prevented urea stimulated activity and nullified the existence of isozymes Ua, Ub, U,, and U2. 35S-U,, which was labeled in the last hour of induction, appeared on fluorogram 1 hour after induction, peaked at 2 hours, and declined at 3 hours. Results indicated that de novo synthesis of urease is activated by the influx of urea.Foliar application of fertilizer to enhance crop productivity has become more popular in recent years (5). It is more beneficial after anthesis when the supply of nutrients through older roots in hot and dry weather becomes inadequate to support the rapid growth of crops (9, 16). The seed protein of 'Scio' barley (Hordeum vulgare L.) was increased by 40% through foliar application of UAN2 after anthesis (24). Foliar spray of urea alone also elevated seed protein content in wheat (6) and increased corn yield (7). Urea uptake and metabolism are rapid in plants and the reduced N is quickly assimilated to increase leaf growth and seed protein following several applications (1,11,24,25). The mechanism of these increases is attributed mainly to the stimulation of nitrogen assimilating enzymes, i.e. nitrate reductase, urease, glutamine synthetase, and glutamate synthetase, within hours after UAN spray (25 Foliar Spray of Urea on Plants. Using a hand atomizer, both sides of the leaves were sprayed with 5% urea in 0.1% Triton X-100 at a rate of approximately 4 ml per pot of 6 to 7 g leaves (14 mg N g-I FW of leaves). The control group was sprayed with the 0.1% Triton X-100 only. The spray was applied at 8:00 AM on each day of the experiment.In Vivo Assay of Urease Activity. In vivo urease activity refers to the assay of enzyme activity in leaf sections. Approximately 2.5 g of leaf samples from comparable positions of the control and treated plants were taken at 0, 1, 2, 3, 4, and 5 h after spray. Four replicated samples of 0.2 g leaf sections (3-5 mm in length) were incubated in 5 ml phosphate buffer consisting of 0.1 M K2HPO4 and 5% (v/v) n-propanol (pH 7.5), with or without 0.2 M urea for 0 and 30 min at 30°C in a water bath with rapid shaking. At each time, an aliquot of 0.5 ml incubation medium was assayed using Hogan's method (8) for ammonia produced. O...

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“…Após ser absorvida, a uréia pode ser hidrolisada no citossol pela enzima urease, gerando dióxido de carbono e amônio (LEHNINGER, 2000). A atividade da urease já foi detectada em muitas plantas (HOGAN et al, 1983;WITTE & MEDINA-ESCOBAR, 2001) e em alguns trabalhos com arroz (MATSUMOTO et al, 1966), feijão (MATSUMOTO et al, 1968) e cevada (CHEN & CHING, 1988), foi demonstrado sua preferência pela uréia. A urease é uma metaloenzima contendo o níquel como grupo prostético e parece ser essencial para tornar o nitrogênio da uréia acessível às plantas (GERENDÁS et al, 1999 As enzimas GS-2 e Fd-GOGAT trabalham em conjunto no cloroplasto.…”

Section: I2-a Folha Como óRgão De Absorção E Assimilaçãounclassified

Assimilação do nitrogênio em diferentes regiões foliares de uma bromélia epífita com tanque

Takahashi¹

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The inducible formation of urease in rice plants

Cited by 22 publications

References 26 publications

Slow Adaptive Changes in Urease Levels of Tobacco Cells Cultured on Urea and Other Nitrogen Sources

Slow Adaptive Changes in Urease Levels of Tobacco Cells Cultured on Urea and Other Nitrogen Sources

Induction of Barley Leaf Urease

Assimilação do nitrogênio em diferentes regiões foliares de uma bromélia epífita com tanque

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