EFFECTS OF TEMPERATURE AND PHOSPHATE CONCENTRATION ON RATE OF SODIUM PYROPHOSPHATE AND SODIUM TRIPOLYPHOSPHATE HYDROLYSIS IN SOIL

1977 ◽  
Vol 57 (3) ◽  
pp. 271-278 ◽  
Author(s):  
C. CHANG ◽  
G. J. RACZ
Keyword(s):  
Incubation Temperature ◽  
Sodium Tripolyphosphate ◽  
Phosphate Concentration ◽  
Water Soluble ◽  
Sodium Pyrophosphate ◽  
Hydrolysis Rate ◽  
Rate Of Hydrolysis ◽  
Effects Of Temperature ◽  
Hydrolysis Of ◽  
Pyrophosphate Hydrolysis

Rates of hydrolysis of water-soluble sodium pyrophosphate and sodium tripolyphosphate, applied to soil at 200 ppm P, were extremely rapid (about 2–7%/h) during the 0 to 24- or 0- to 48-h period following phosphate application but decreased with time of incubation. Rates of hydrolysis increased linearly and increased about two- to threefold as temperatures were increased from 5 to 35 C or from 5 to 50 C. Inconsistent results were obtained at temperatures above 50 C. Increases in incubation temperature increased the total amount of added polyphosphate hydrolyzed by the soil in 120 h from about 40 to 70% at 5 C to about 80 to 95% at 35 C and 50 C. Water-soluble polyphosphate hydrolyzed at a greater rate than 0.5 N H2SO4-soluble polyphosphate. However, the effects of temperature on rate of hydrolysis of acid-soluble polyphosphate and water-soluble polyphosphate were similar. Polyphosphate hydrolyzed at a greater rate in the noncalcareous Newdale soil than in the calcareous Lakeland soil. Rate of tripolyphosphate hydrolysis was usually greater than rate of pyrophosphate hydrolysis. Rate of hydrolysis of water-soluble polyphosphate, expressed as %/h, decreased exponentially as concentration of applied polyphosphate increased from 200 to 1,600 ppm. However, rate of orthophosphate production per unit time increased exponentially with increased substrate concentration.

Phytotoxic Effect of Decaying Quackgrass (Agropyron repens) Residues

Weed Science ◽  
1979 ◽  
Vol 27 (6) ◽  
pp. 595-598 ◽  
Author(s):  
T. V. Toai ◽  
D. L. Linscott
Keyword(s):  
Incubation Temperature ◽  
Soil Surface ◽  
Water Soluble ◽  
Water Extracts ◽  
Phytotoxic Activity ◽  
Phytotoxic Effect ◽  
Effects Of Temperature ◽  
Incubation Temperatures ◽  
Toxin Formation ◽  
Agropyron Repens

We studied the effects of temperature (5, 10, 20, and 30 C) on the phytotoxic activity of decaying quackgrass [Agropyron repens (L.) Beauv.] leaves and rhizomes that were incubated in soils for 0, 1, 2, 4, and 6 weeks. Alfalfa (Medicago sativa L.) seeds were grown for 96 h in water, water extracts of control soils, and water extracts of soil with quackgrass rhizomes or leaves. Dried quackgrass rhizomes and leaves contained water-soluble toxins that inhibited alfalfa seedling development and growth. There was a strong interaction between incubation time and temperature on the development of additional toxins by decomposing quackgrass. High incubation temperature (30 C) accelerated toxin formation and ultimate decay. Intermediate temperature (20 C) delayed toxin formation and decay. Low incubation temperatures (5 C and 10 C) prevented formation of additional toxin. In all extracts of quackgrass and soil that had been incubated for 6 weeks, normal alfalfa seedling number equaled that in water. However, seedling growth varied with incubation temperatures.Treatment of quackgrass with glyphosate [N-(phosphonomethyl) glycine] in the greenhouse did not influence the toxicity of decaying quackgrass leaves. The highest toxic effect was noted after 1 week of decay on the soil surface.

scholarly journals Stability of unimolecular films of 32P-labelled lecithin

1967 ◽  
Vol 105 (1) ◽  
pp. 401-407 ◽  
Author(s):  
H. Hauser ◽  
R. M. C. Dawson
Keyword(s):  
Pressure Change ◽  
Ion Concentration ◽  
Hydrolysis Rate ◽  
Ion Distribution ◽  
Rapid Perfusion ◽  
Poisson Boltzmann ◽  
Rate Of Hydrolysis ◽  
Poisson Boltzmann Equation ◽  
The Stability ◽  
Hydrolysis Of

1. The stability of monolayers of a highly unsaturated yeast lecithin labelled with 32P has been investigated by a surface radioactivity technique. 2. Lecithin films on distilled water at all surface pressures between 6 and 48dynes/cm. were completely stable on rapid perfusion of the subphase and on addition of ionic amphipathic substances to the film. 3. Ultrasonically treated lecithin added to the subphase caused a slow loss of surface radioactivity but little pressure change. 4. The addition of proteins to the subphase caused negligible changes in the film even when conditions were favourable for electrostatic heterocoagulation and penetration. 5. Lecithin films were not hydrolysed by a strongly acid subphase at room temperature. The very low rate of hydrolysis produced by alkali was proportional to the subphase OH−ion concentration: the apparent activation energy and temperature coefficient (Q10) of the reaction were 14250 cal. and 2·37 respectively. 6. Alkaline hydrolysis of lecithin monolayers was markedly stimulated by adding methanol (10–20%, v/v) to the subphase. The addition of ionic amphipaths to the monolayer had the expected type of effect on the hydrolysis rate, but its magnitude was far less than that suggested by an application of the Poisson–Boltzmann equation for ion distribution at a charged interface (Davies & Rideal, 1963).

scholarly journals Genetic control of the hydrolysis of aromatic esters by sheep plasma A-esterase

1966 ◽  
Vol 7 (3) ◽  
pp. 373-382 ◽  
Author(s):  
R. M. Lee
Keyword(s):  
Esterase Activity ◽  
Phosphate Esters ◽  
Hydrolysis Rate ◽  
Aromatic Esters ◽  
Hydrolysis Rates ◽  
Rate Of Hydrolysis ◽  
Hydrolysis Of ◽  
Naphthyl Acetate ◽  
Genetic Marking ◽  
Genetic Hypothesis

1. The rate of hydrolysis by sheep plasma of some carboxylic and phosphate esters has been determined for a random flock, and for a flock previously selected for its ability to hydrolyse di-(2-chloroethyl) aryl phosphates.2. A discontinuous variation in hydrolysis rate was found with all substrates tested and, using combinations of substrates, six types of plasma could be distinguished, each type having a different pattern of esterase activity.3. The most useful substrates for distinguishing between phenotypes were 1-naphthyl acetate and 4-ethoxycarbonylcoumarin-7-yl acetate. Three rates of hydrolysis were possible for each of these esters, and the highest rate for one was invariably combined with the lowest rate for the other, although the converse did not apply.4. To explain these results, and those of Lee (1964), it has been postulated that the quantitative production of esterase hydrolysing 1-naphthyl acetate is governed by the presence of an allele, termed Esa, at a particular gene locus. Similarly, the production of esterase hydrolysing 4-ethoxycarbonylcoumarin-7-yl acetate is determined by allele Esb, and where neither substrate is attacked the presence of a third allele, Esc, is proposed.5. The hydrolysis rates of haloxon, 1-naphthyl butyrate and 4-nitrophenyl butyrate varied in the same way as that of 1-naphthyl acetate, whereas the hydrolysis of indophenyl acetate followed the same pattern as that of 4-ethoxycarbonylcoumarin-7-yl acetate. The variation in hydrolysis rate of Coroxon could be explained by assuming that Esa and Esb are equal in this respect.6. A mating experiment produced results which were in accordance with the genetic hypothesis, but were too few in number to provide confirmation.7. The genetic marking of six types of sheep is possible, utilizing the variation in plasma A-esterase activity.

scholarly journals Hydrolysis of GTP by Sec4 protein plays an important role in vesicular transport and is stimulated by a GTPase-activating protein in Saccharomyces cerevisiae.

1992 ◽  
Vol 12 (5) ◽  
pp. 2017-2028 ◽  
Author(s):  
N C Walworth ◽  
P Brennwald ◽  
A K Kabcenell ◽  
M Garrett ◽  
P Novick
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Synthetic Lethality ◽  
Vesicular Transport ◽  
Yeast Cells ◽  
Hydrolysis Rate ◽  
Phosphoryl Group ◽  
Absolute Level ◽  
Yeast Saccharomyces Cerevisiae ◽  
Rate Of Hydrolysis ◽  
Hydrolysis Of

Sec4, a GTP-binding protein of the ras superfamily, is required for exocytosis in the budding yeast Saccharomyces cerevisiae. To test the role of GTP hydrolysis in Sec4 function, we constructed a mutation, Q-79----L, analogous to the oncogenic mutation of Q-61----L in Ras, in a region of Sec4 predicted to interact with the phosphoryl group of GTP. The sec4-leu79 mutation lowers the intrinsic hydrolysis rate to unmeasurable levels. A component of a yeast lysate specifically stimulates the hydrolysis of GTP by Sec4, while the rate of hydrolysis of GTP by Sec4-Leu79 can be stimulated by this GAP activity to only 30% of the stimulated hydrolysis rate of the wild-type protein. The decreased rate of hydrolysis results in the accumulation of the Sec4-Leu79 protein in its GTP-bound form in an overproducing yeast strain. The sec4-leu79 allele can function as the sole copy of sec4 in yeast cells. However, it causes recessive, cold-sensitive growth, a slowing of invertase secretion, and accumulation of secretory vesicles and displays synthetic lethality with a subset of other secretory mutants, indicative of a partial loss of Sec4 function. While the level of Ras function reflects the absolute level of GTP-bound protein, our results suggest that the ability of Sec4 to cycle between its GTP and GDP bound forms is important for its function in vesicular transport, supporting a mechanism for Sec4 function which is distinct from that of the Ras protein.

scholarly journals Study of Hydrolization and Sedimantationin Acid Compositions Based on Sulfaminic Acid

2020 ◽  
Vol 130 (5) ◽  
pp. 32-37
Author(s):  
L. A. Magadova ◽  
◽  
A. N. Sirotin ◽  
M. D. Pakhomov ◽  
Z. R. Davletov ◽  
...  
Keyword(s):  
Hydrochloric Acid ◽  
Calcium Sulfate ◽  
Gravimetric Method ◽  
Sulfamic Acid ◽  
Hydrolysis Rate ◽  
Hydrolysis Products ◽  
Rate Of Hydrolysis ◽  
Quartz Solubility ◽  
Ammonium Sulfamate ◽  
Hydrolysis Of

This article presents the results of a study of the hydrolysis of sulfamic acid and the elaboration of acidic compositions that are characterized by reduced sedimentation compared to mud acid. The effect of complexing compounds on the hydrolysis of sulfamic acid is considered, the hydrolysis of sulfamic acid and sulfamates is compared, and the secondary sedimentation of sulfamic acid and mud acid compositions is compared using the formation of hexafluorosilicates. The hydrolysis intensity of sulfamic acid and ammonium sulfamate was determined by the mass of sediments formed during the reaction of hydrolysis products with calcium chloride. The mass of calcium sulfate formed is proportional to the rate of hydrolysis of sulfamic acid. The process of dissolution of the quartz component of the terrigenous formation was studied using the gravimetric method. Differences in influence of EDTA, HEDP, and NTP on sedimentation prevention of the products of sulfamic acid hydrolysis were studied by the example of reactions with Ca2+. It was shown that compositions with NTP are characterized by a lower sediments formation. The ratio of NTP concentration and the hydrolysis rate of sulfamic acid is shown. Differences in the hydrolysis rate of compositions based on sulfamic acid and sulfamates were determined at a temperature of 80°C. It was shown that sulfamates are characterized by a lower rate of hydrolysis. Differences in quartz solubility were determined for compositions based on sulfamic and sulfuric acids, differences in the reactions kinetics were shown. It has been established that acid compositions based on sulfamic acid are characterized by less sedimentation rate being compared with acid compositions based on hydrochloric acid by the example of hexafluorosilicates formation.

Determination of the Tacticity of Poly(methyl methacrylate) by Hydrolysis Rate Measurements

1992 ◽  
Vol 57 (2) ◽  
pp. 349-356 ◽  
Author(s):  
František Mikeš ◽  
Jan Pecka
Keyword(s):  
Methyl Methacrylate ◽  
Ester Group ◽  
Hydrolysis Rate ◽  
Nucleophilic Attack ◽  
Carbonyl Carbon Atom ◽  
Poly Methyl Methacrylate ◽  
Carboxylic Groups ◽  
Simple Kinetic Model ◽  
Rate Of Hydrolysis ◽  
Hydrolysis Of

The rate of hydrolysis of poly(methyl methacrylate) increases with the content of meso(isotactic) diads in the polymer. The increase in the rate of hydrolysis of isotactic polymers is due to an intramolecular nucleophilic attack by the adjacent carboxylic ion on the carbonyl carbon atom in the ester group. An analysis of the content of sequences of variously arranged ester and carboxylic groups shows that the hydrolysis of s-poly(methyl methacrylate) is a random process, while i-poly(methyl methacrylate) is hydrolyzed gradually (by zip mechanism), starting from the carboxylate group formed by an external attack by hydroxylic ions. The kinetic data thus obtained cannot be interpreted in terms of a simple kinetic model. The tacticity of poly(methyl methacrylate) may be estimated from the dependence of the rate of hydrolysis on the content of meso diads determinated by NMR spectrometry. The rate of hydrolysis depends not only on the tacticity of the polymer, but probably also on its configurational sequence statistics.

Interaction of Actomyosin and Adenosinetriphosphate as Studied With Glycerol-Extracted Cardiac Muscle Bundles

1958 ◽  
Vol 194 (3) ◽  
pp. 564-572 ◽  
Author(s):  
Ellis S. Benson ◽  
Ben E. Hallaway
Keyword(s):  
Ionic Strength ◽  
Atp Hydrolysis ◽  
Divalent Cations ◽  
Isometric Tension ◽  
Tension Development ◽  
Sodium Magnesium ◽  
Rate Of Hydrolysis ◽  
Effects Of Temperature ◽  
The Right ◽  
Hydrolysis Of

Glycerol-extracted muscle bundles were obtained from the right and left ventricles of dogs. Isometric tension developed on addition of adenosinetriphosphate (ATP) and resistance to stretch of the extracted bundles and the rate of ATP hydrolysis of the myofibrillar components of the bundle were studied. Effects of temperature, ionic strength, pH and concentrations of ATP, sodium, magnesium and calcium were evaluated. The results indicated that the contractile phenomenon producing tension is a complex of at least two underlying reactions one of which promotes contraction ( R1) and the other ( R2) relaxation. Which of these reactions limits tension development is determined by the concentration of ATP. The concentration at which the transition takes place between R1 as the limiting reaction to R2 is a function of temperature, ionic strength, pH and the concentration of calcium ions. R1 appears to be associated with the hydrolysis of ATP and this may be the energy-supplying reaction. Certain findings in regard to the effect of concentration of divalent cations on the contractile response and the rate of hydrolysis are difficult to reconcile, however, with the contention that R1 is a reaction in which ATP is hydrolyzed. At very low concentration of Mg and Ca, hydrolysis is strikingly inhibited though contraction takes place. Furthermore, concentrations of Mg of the order of 2 x 10–2 m inhibit enzymatic hydrolysis and promote contraction. Concentrations of Ca of 10–2 m inhibit contraction but accelerate ATP hydrolysis.

The effects of hydraulic retention time and feed COD concentration on the rate of hydrolysis of primary sewage sludge under methanogenic conditions

2006 ◽  
Vol 54 (5) ◽  
pp. 91-100 ◽  
Author(s):  
N.E. Ristow ◽  
S.W. Sötemann ◽  
M.C. Wentzel ◽  
R.E. Loewenthal ◽  
G.A. Ekama
Keyword(s):  
Steady State ◽  
Sewage Sludge ◽  
Retention Time ◽  
Hydraulic Retention Time ◽  
Mean Value ◽  
Operating Conditions ◽  
Hydrolysis Rate ◽  
Feed Concentration ◽  
Rate Of Hydrolysis ◽  
Hydrolysis Of

A series of completely mixed methanogenic anaerobic digesters have been operated to determine the rate of hydrolysis of primary sewage sludge. The hydraulic retention time was reduced from 60 d to when the system failed (∼5 d), while the feed COD concentration was 40, 25, 13 and 2 gCOD/L. A steady state model based on first order kinetics was developed to simulate the hydrolysis rate at each retention time and feed concentration. With the mean value for the hydrolysis rate constant (0.992±0.492 d−1), this model was able to accurately predict the effluent COD for all steady state operating conditions. However, the effluent COD concentration was relatively insensitive to the exact value for this constant. The model provides a framework for analysis of anaerobic digestion experimental data, to enable meaningful comparisons.

Hydrolysis of GTP by Sec4 protein plays an important role in vesicular transport and is stimulated by a GTPase-activating protein in Saccharomyces cerevisiae

1992 ◽  
Vol 12 (5) ◽  
pp. 2017-2028
Author(s):  
N C Walworth ◽  
P Brennwald ◽  
A K Kabcenell ◽  
M Garrett ◽  
P Novick
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Synthetic Lethality ◽  
Vesicular Transport ◽  
Yeast Cells ◽  
Hydrolysis Rate ◽  
Phosphoryl Group ◽  
Absolute Level ◽  
Yeast Saccharomyces Cerevisiae ◽  
Rate Of Hydrolysis ◽  
Hydrolysis Of

Sec4, a GTP-binding protein of the ras superfamily, is required for exocytosis in the budding yeast Saccharomyces cerevisiae. To test the role of GTP hydrolysis in Sec4 function, we constructed a mutation, Q-79----L, analogous to the oncogenic mutation of Q-61----L in Ras, in a region of Sec4 predicted to interact with the phosphoryl group of GTP. The sec4-leu79 mutation lowers the intrinsic hydrolysis rate to unmeasurable levels. A component of a yeast lysate specifically stimulates the hydrolysis of GTP by Sec4, while the rate of hydrolysis of GTP by Sec4-Leu79 can be stimulated by this GAP activity to only 30% of the stimulated hydrolysis rate of the wild-type protein. The decreased rate of hydrolysis results in the accumulation of the Sec4-Leu79 protein in its GTP-bound form in an overproducing yeast strain. The sec4-leu79 allele can function as the sole copy of sec4 in yeast cells. However, it causes recessive, cold-sensitive growth, a slowing of invertase secretion, and accumulation of secretory vesicles and displays synthetic lethality with a subset of other secretory mutants, indicative of a partial loss of Sec4 function. While the level of Ras function reflects the absolute level of GTP-bound protein, our results suggest that the ability of Sec4 to cycle between its GTP and GDP bound forms is important for its function in vesicular transport, supporting a mechanism for Sec4 function which is distinct from that of the Ras protein.

THE EFFECT ON REACTION RATES CAUSED BY THE SUBSTITUTION OF C14 FOR C12: I. THE ALKALINE HYDROLYSIS OF CARBOXYL-LABELED ETHYL BENZOATE

1949 ◽  
Vol 27b (10) ◽  
pp. 807-812 ◽  
Author(s):  
William H. Stevens ◽  
Richard W. Attree
Keyword(s):  
Alkaline Hydrolysis ◽  
Rate Constants ◽  
Room Temperature ◽  
Reaction Rates ◽  
Ethyl Benzoate ◽  
Hydrolysis Rate ◽  
Rate Of Hydrolysis ◽  
Hydrolysis Of

A study of the alkaline hydrolysis of C14 carboxyl-labeled ethyl benzoate has shown that the substitution of C14 for C12 changes the rate of hydrolysis of the ester. Ester molecules containing C14 hydrolyze at a slower rate than normal ester molecules. The ratio of the hydrolysis rate constants at room temperature has been found to be 0.86 ± 0.016.

Sign in / Sign up

Export Citation Format

Share Document