Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P39060 (endostatin)
 2,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The release mechanism of gel-based controlled release fertilizers (CRFs) involves water penetration into dry mixtures of fertilizers and gel forming polymers. Water penetration provides an upper limit to the whole release process. Where wetting prediction is often based on models that describe the flow of the liquid phase, vapor motion may become significant when a sharp wetting front exists. In this study we examine the role of vapor and fluid flows in the wetting process of CRFs consisting of urea or KNO(3) mixed with polyacrylamide (PAM). Vapor adsorption isotherms were obtained for typical fertilizer-PAM mixtures. Wetting and release experiments were conducted by dividing the CRFs into regions alternately filled with a pure fertilizer and mixtures of PAM and fertilizer. The experiments were designed in such a way that when the wetting front reaches a mixtures interface, its motion depends on the gradient imposed by the difference in osmotic potential (OP). The coupled equations of vapor and liquid flow in initially dry conditions were solved numerically to demonstrate the conceptual understanding gained by the experiments. The results show that wetting front motion is affected by transport and adsorption of vapor. It was also shown that the release rate is different when wetting is governed by vapor flow or by liquid flow. The release pattern from a multi-regions device was consistent with the wetting pattern, demonstrating the possibility to tailor the release according to periods of peak demand.
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PMID:Wetting mechanisms of gel-based controlled-release fertilizers. 1258 5

The number of viable Escherichia coli in a young, actively growing culture is decreased approximately 99.9 per cent by a 30 second exposure to 25 phig. streptomycin/ml. The injury induced by the antibiotic is only potentially lethal, however, and may be reversed by subculture within 5 minutes into fresh culture medium, NH(4)NO(3), NH(4)Cl, (NH(4))(2)HPO(4), NH(4) citrate, and NH(4) tartrate. Subculturing into water, glucose, or MgSO(4) results in a more marked decrease in the number of viable organisms. In KNO(3), NaNO(3), K(2)HPO(4), and Na(2)SO(4) solutions reversal occurs first, followed by a rapid decrease in viability. True reversal of the streptomycin injury takes place, as demonstrated by the rapid rate of recovery to the viable count of the original culture. Development of resistance has been eliminated as the cause of regrowth since the streptomycin sensitivity of recovered cultures remained the same as that of the original culture. The use of water as diluent for viability determinations potentiates the lethal effect of streptomycin activity. Several compounds, at various dilutions, substituted for water as the diluent gave rise to four types of responses, group I, NH(4)NO(3), NH(4)Cl, KNO(3), NaNO(3), Ca(NO(3))(2), showed complete reversal of the streptomycin injury at all levels of the salts tested, from 0.01 to 0.5 M concentrations. Group II, NaCl and K(2)HPO(4) showed complete reversal at 0.03 and 0.1 M. Group III, glucose and urea allowed complete reversal at 0.5 M. Group IV, glycerol and glycerine showed no reversal at 0.5 M concentration. The reversal of the streptomycin injury to young actively growing bacteria is suggested as a tool for studying the pathology of the injury to the cells.
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PMID:Reversal of the streptomycin injury of Escherichia coli. 1321 97

Endostatin is a potent angiogenesis inhibitor. The structure of endostatin is unique in that its secondary structure is mainly irregular loops and beta-sheets and contains only a small fraction of alpha-helices with two pairs of disulfide bonds in a nested pattern. We choose human endostatin as a model system to study the folding mechanism of this kind. Nuclear magnetic resonance (NMR), tryptophan emission fluorescence, and circular dichroism (CD) were used to monitor the unfolding process of endostatin upon acid titration. Urea-induced unfolding was used to measure the stability of endostatin under different conditions. Our results show that endostatin is very acid-resistant; some native structure still remains even at pH 2 as evidenced by (1)H NMR. Trifluoroethanol (TFE) destabilizes native endostatin, while it makes endostatin even more acid-resistant in the low pH region. Stability measurement of endostatin suggests that endostatin is still in native structure at pH 3.5 despite the decreased stability. Acid-induced unfolding of endostatin is reversible, although it requires a long time to reach equilibrium below pH 3. Surprisingly, the alpha-helical content of endostatin is increased when it is unfolded at pH 1.6, and the alpha-helical content of the polypeptide chain of unfolded endostatin increases linearly with TFE concentration in the range of 0-30%. This observation indicates that the polypeptide chain of unfolded endostatin has an intrinsic alpha-helical propensity. Our discoveries may provide clues for refolding endostatin more efficiently. The acid-resistance property of endostatin may have biological significance in that it cannot be easily digested by proteases in an acidic environment such as in a lysosome in the cell.
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PMID:Acid-induced unfolding mechanism of recombinant human endostatin. 1499 92

Cultured soybean (Glycine max, Kanrich variety) cells grow with 25 mm urea as the sole nitrogen source but at a slower rate than with the Murashige and Skoog (MS) (Physiol. Plant. 15: 473-497, 1962) nitrogen source of 18.8 mm KNO(3) and 20.6 mm NH(4)NO(3). Growth with urea is restricted by 18.8 mm NO(3) (-), 50 mm methylammonia, 10 mm citrate or 100 mum hydroxyurea, substances which are much less restrictive or nonrestrictive in the presence of ammonia nitrogen source. The restrictive conditions of urea assimilation were examined as possible bases for selection schemes to recover urease-overproducing mutants. Since urease has higher methionine levels than the soybean seed proteins among which it is found, such selections may be a model for improving seed protein quality by plant cell culture techniques.Callus will not grow with 1 mm urea plus 18.8 mm KNO(3). Urease levels decrease 80% within two divisions after transfer from MS nitrogen source to 1 mm urea plus 18.8 mm KNO(3). Hydroxyurea is a potent inhibitor of soybean urease and this appears to be the basis for its inhibition of urea utilization by callus cells.Stationary phase suspension cultures grown with MS nitrogen source exhibit trace or zero urease levels. Soon after transfer to fresh medium (24 hours after escape from lag), urease levels increase in the presence of both MS or urea nitrogen source. However, the increase is 10 to 20 times greater in the presence of urea. NH(4)Cl (50 mm) lowers urease induction by 50% whereas 50 mm methylammonium chloride results in more drastic reductions in urea-stimulated urease levels. Citrate (10 mm) completely blocks urease synthesis in the presence of urea.Ammonia and methylammonia do not inhibit soybean urease nor do they appreciably inhibit urea uptake by suspension cultures. It appears likely that methylammonia inhibits urea utilization in cultured soybean cells primarily due to its "repressive" effect on urease synthesis.Citrate does not inhibit urease activity in vitro and exhibits only a partial inhibition (0-50% in several experiments) of urea uptake. It appears likely that the citrate elimination of urease production by cultured soybean cells is due to its chelation of trace Ni(2+) in the growth medium. Dixon et al. (J. Am. Chem. Soc. 97: 4131-4133, 1975) have reported that jack bean (Canavalia ensiformis) urease contains nickel at the active site.
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PMID:Nitrogen metabolism in soybean tissue culture: I. Assimilation of urea. 1665 77

Experiments were conducted to characterize the distribution of N compounds in the xylem sap of nodulated and nonnodulated soybean plants through development and to determine the effects of exogenous N on the distribution of N compounds in the xylem. Xylem sap was collected from nodulated and nonnodulated greenhouse-grown soybean plants (Glycine max [L.] Merr. "Ransom") from the vegetative phase to the pod-filling phase. The sum of the nitrogen in the amino acid, nitrate, ureide (allantoic acid and allantoin), and ammonium fractions of the sap from both types of plants agreed closely with total N as assayed by a Kjeldahl technique. Sap from nodulated plants supplied with N-free nutrient solution contained seasonal averages of 78 and 20% of the total N as ureide-N and amino acid-N, respectively. Sap from nonnodulated plants supplied with a 20 millimolar KNO(3) nutrient solution contained seasonal averages of 6, 36, and 58% of total N as ureide-N, amino acid-N, and nitrate-N, respectively. Allantoic acid was the predominant ureide in the xylem sap and asparagine was the predominant amino acid. When well nodulated plants were supplied with 20 millimolar KNO(3), beginning at 65 days, C(2)H(2) reduction (N(2) fixation) decreased relative to nontreated plants and there was a concomitant decrease in the ureide content of the sap. A positive correlation (r = 0.89) was found between the ureide levels in xylem sap and nodule dry weights when either exogenous nitrate-N or urea-N was supplied at 10 and 20 millimolar concentrations to inoculated plants. The results demonstrate that ureides play a dominant role in N transport in nodulated soybeans and that the synthesis of ureides is largely dependent upon nodulation and N(2) fixation.
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PMID:Transport of nitrogen in the xylem of soybean plants. 1666 Sep 77

The main objectives of this work were to study the effect of different N sources on plant growth, N accumulation, and on the expression of nitrate reductase activity in Phaseolus vulgaris L. leaves. Plants were grown under greenhouse conditions (15 to 25 kilolux; 16/8 hour day/night cycles) in plastic pots filled with perlite: vermiculite (1:1) and watered daily with a minus N solution (N(2) plants) or supplemented with either KNO(3), (NH(4))(2)SO(4), or urea as combined N sources.Significant levels of nitrate reductase activity in trifoliolate leaves of N(2)-, NH(4) (+)-, urea-, or NO(3) (-)-dependent plants was demonstrated throughout this work. Leaves from the urea- or NH(4) (+)-grown plants accumulated NO(2) (-) in the dark but not in the light when NO(2) (-) was supplied by vacuum infiltration. These results indicated that the potential for reduction of NO(3) (-) or NO(2) (-) was not impaired by growing the plants on NH(4) (+) or urea and, in addition, provided evidence for the occurrence of a non-nitrate-inducible nitrite reductase. The nitrate reductase activities associated with N(2)-, NH(4) (+)-, or urea-dependent plants are tentatively regarded as ;constitutive' to differentiate from the widely occurring NO(3) (-)-inducible nitrate reductase activity.Plants grown on NO(3) (-) or urea accumulated significantly larger amounts of reduced N and dry matter as compared to NH(4) (+)- and N(2)-dependent plants. Regardless of N treatment, or size of plants, about 50% of the N accumulated by the plant was allocated to the leaves.
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PMID:Expression of Nitrate and Nitrite Reductase Activities under Various Forms of Nitrogen Nutrition in Phaseolus vulgaris L. 1666 85

The nodulation characteristics of soybean (Glycine max) mutant nts382 are described. The mutant nodulated significantly more than the parent cultivar Bragg in the presence and absence of several combined nitrogen sources (KNO(3), urea, NH(4)Cl, and NH(4)NO(3)). The number of nodules on the tap root and on lateral roots was increased in the mutant line. In the presence of KNO(3) and urea, nitrogenase activity was considerably higher in nts382 than in Bragg. Mutant plants were generally smaller than wild-type plants. Although nts382 is a supernodulator, inoculation with Rhizobium japonicum was necessary to induce nodule formation and both trial strains CB1809 (= USDA136) and USDA110 elicited the mutant phenotype. Segregation of M(3) progeny derived from a M(2) wild-type plant indicated that the mutant character is inherited as a Mendelian recessive. The mutant is discussed in the context of regulation of nodulation and of hypotheses that have been proposed to explain nitrate inhibition of nodulation.
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PMID:A Supernodulation and Nitrate-Tolerant Symbiotic (nts) Soybean Mutant. 1666 3

Endostatin, a potent angiogenesis inhibitor, is an acid resistant protein with compact tertiary structure. Nuclear magnetic resonance, circular dichroism, and tryptophan emission fluorescence were used to monitor the structural changes of endostatin during acid-, heat-, and urea-induced unfolding processes. Results show that sulfate anions sensitize endostatin to acid, but specifically stabilize it against heat or urea. Moreover, the disappearance of the tertiary structure and the formation of the folding intermediate of endostatin at pH 3.0 are sulfate concentration dependent. These phenomena indicate that sulfate anions stabilize the folding intermediate more than the native structure of endostatin. In addition, heparin shows stronger effect than sodium sulfate on sensitizing endostatin against acid, and very limited stabilizing effect against urea. The loose structure of endostatin upon heparin binding may imply that the physiologically favorable structure for endostatin exerting its biological functions is not as compact as what was reported.
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PMID:Sulfate stabilizes the folding intermediate more than the native structure of endostatin. 1818 53

ABSTRACT Deformation disease of Gypsophila paniculata mother plants reduces cutting yields as much as 50% but does not kill the mother plants. In preliminary experiments, fertigation of G. paniculata mother plants with a 20:20:20 compound fertilizer (N, P, K, plus microelements) at an N concentration of 720 mg/liter reduced the expression of deformation disease compared with the conventional N concentration of 360 mg/liter. The current study determined which component of the compound fertilizer reduced the disease. Experiments were carried out in 10-liter buckets packed with naturally infested 0- to 8-mm black tuff (Scoria = crushed volcanic stones). Irrigation was applied once a day at 0.5 liter per bucket with the nutrient under test being added at 1.0 liter per bucket via the water once a week. Treatments included: (i) four levels of 20:20:20 fertilizer; (ii) four levels of each of N, P, K, and Fe-Zn-Mn mixture (ME) corresponding to their concentrations in the compound fertilizer; (iii) different N sources (20:20:20, (NH(4))(2)SO(4), KNO(3), NH(4)NO(3), urea); and (iv) three pHs of the irrigation water at each of three NO(3) and NH(4) application levels. Increasing the 20:20:20 fertilizer concentration reduced the disease level from 82 to 96% with N at 180 mg/liter to 6 to 10% with N at 720 mg/liter. When either P, K, or ME was the sole variable, increasing concentrations had no significant effect on the disease, but elevating a mixed source nitrogen concentration from 0 to 180, 360, and 720 mg/liter (as 50% urea, 40% NH(4)NO(3), and 10% KNO(3)) significantly reduced deformation similar to that observed with increasing concentrations of the 20:20:20 fertilizer. mong tested N sources, NH(4) was the most effective in reducing the disease (almost to zero at an N concentration of 360 g/liter). Low disease incidence (0 to 10%) was always associated with effluent pH of 6 or lower. Irrigating with acidified water pH 5.5) in the presence of N, as NH(4) at 180 mg/liter, additionally reduced disease from 56% under tap water (pH 7.8) rrigation to 11%. Similar acidification in the presence of NO (-) (3) N at 180 mg/liter was ineffective in reducing the disease, but ater basification in the presence of NO (-) (3) N reduced disease incidence from 93 to 38% 90 days after planting. The N, P, K, Fe, and Zn concentrations in gypsophila cuttings were similar under the three tested levels of NH(4), NO(3), and 20:20:20, whereas the concentration of Mn increased with increasing N. The Mn concentration in cuttings was inversely correlated with disease and is probably an important factor to understanding the physiological background of the deformation disease.
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PMID:Effect of Nutrition on Deformation Disease in Gypsophila paniculata Mother Plants. 1894 51

Numbers of Pratylenchus penetrans in sterilized soil decreased significantly 2 weeks after the addition of 1% w/w (700 ppm N) nonsterile soybean meal (SBM), or sterilized SBM in combination with selected microorganisms. Sterilized SBM had no effect on nematode populations in steamed soil. Bacteria and fungi in the presence of SBM were more effective than the actinomycetes tested, causing up to 96-100% reduction in nematode populations. Simpler nitrogenous compounds included KNO, Ca(NO), NHNO, (NH)CO, urea, and peptone, decreased nematode populations with variable effectiveness when added to steamed soil at 700 ppm N; KNO was the most nematicidal.
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PMID:Pratylenchus penetrans (Cobb) Populations as Influenced by Microorganisms and Soil Amendments. 1932 87


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