Influence of four levels of pyrophosphatase activity on the rate of pyrophosphate hydrolysis in organic soils

1985 ◽  
Vol 16 (10) ◽  
pp. 1095-1105 ◽  
Author(s):  
L.E. Parent ◽  
A.F. MacKenzie ◽  
Y. Perron
1985 ◽  
Vol 65 (3) ◽  
pp. 497-506 ◽  
Author(s):  
L. E. PARENT ◽  
A. F. MacKENZIE

Twenty-four organic soil materials were selected in order to study pyrophosphatase activity and pyrophosphate retention and hydrolysis. The activation energy of pyrophosphate hydrolysis was 22 kJ∙mol−1 for virgin fibric soil materials and 33 kJ∙mol−1 for cultivated humic soil materials. Phosphatase and pyrophosphatase activities were highly correlated (r = 0.947**) and were promoted apparently by non-specific enzymes. Enzymatic activities varied from 11.6 to 148.1 mmol∙kg−1∙(2 h)−1, and were higher in virgin than in cultivated soil materials. Soil retention increased with an increase in ash content (r = 0.876**) and was apparently weak, as noted by complete pyrophosphate hydrolysis after 4–8 days of incubation. Half-life values of pyrophosphate incubated at room temperture varied from 0.1 to 3.7 days, and were highly correlated with enzymatic activities and levels of nonretained pyrophosphate. A regression model, involving an interaction between pyrophosphatase activity and level of nonretained pyrophosphate, accounted for 77% of the variation in log of half-life values of pyrophosphate in organic soil materials. Key words: Pyrophosphatase, phosphatase, pyrophosphate, half-life values, pyrophosphate retention


1985 ◽  
Vol 65 (4) ◽  
pp. 1091-1095 ◽  
Author(s):  
L. E. PARENT ◽  
A. F. MACKENZIE ◽  
Y. PERRON

The rate of phosphorus uptake by onions was compared to the rate of pyrophosphate hydrolysis in mesic (MSM) and humic soil materials (HSM). Dry matter production and P uptake were very small from seeding to leek stage but increased considerably toward bulb maturity. Pyrophosphate half-life was 2 days in the HSM and 4 wk in the MSM, since addition of Ca(OH)2 markedly decreased pyrophosphatase activity and amounts of non-retained pyrophosphate in the MSM. By the time of high P demand by the crop, pyrophosphate was completely hydrolyzed in the HSM and most of it was already hydrolyzed in the MSM. These results suggest comparable availability of orthophosphate and pyrophosphate for onions grown in organic soils.Key words: Allium cepa L., onion growth, polyphosphates, Histosol, pyrophosphatase activity


1969 ◽  
Vol 112 (5) ◽  
pp. 699-701 ◽  
Author(s):  
D W Moss

1. The differential effects of adding Zn2+ and Mg2+ on the orthophosphatase and inorganic pyrophosphatase activities of human intestinal alkaline phosphatase were studied. 2. In the presence of excess of Zn2+, inorganic pyrophosphatase activity is inhibited. At higher concentrations of pyrophosphate, hydrolysis of this substrate takes place, but is inhibited competitively by the Zn2+–pyrophosphate complex. This complex also acts as a competitive inhibitor of orthophosphate hydrolysis. 3. Excess of Mg2+ also inhibits pyrophosphatase action by removal of substrate; at low concentrations, this ion activates pyrophosphatase, as is the case with orthophosphatase. 4. It is concluded that, when interactions between metal ions and pyrophosphate are taken into account, the effects of these ions are consistent with the view that alkaline phosphatases possess both orthophosphatase and inorganic pyrophosphatase activities.


1983 ◽  
Vol 63 (2) ◽  
pp. 221-228 ◽  
Author(s):  
S. P. MATHUR ◽  
R. B. SANDERSON ◽  
A. BELANGER ◽  
M. VALK ◽  
E. KNIBBE ◽  
...  

To assess effects of soil Cu on the yield and nutrition of a crop, onions (Allium cepa ’Autumn Spice’) were grown in field microplots at sites A (peat), B (muck) and C (mucky peat). The surface layers (0–20 cm) of the plots contained four levels of residual fertilizer Cu up to 1200 ppm (wt/wt) at sites A and B and up to 600 ppm at site C. The highest Cu treatment at sites A and B contained about 4–6 times the Cu required for mitigating the excessive decomposition and subsidence of such organic soils. Neither the Cu treatment level nor the total soil Cu concentration influenced crop yields at sites B or C. Crop yield responded positively to the two highest Cu treatment levels at site A where the background level of soil Cu was the lowest among the three sites. The Cu concentrations in the crop at all sites were below the level considered to be phytotoxic (20 ppm). Fe and Zn contents in plants were also not depressed by higher Cu concentrations except for foliar Fe on the highest Cu treatment plots at site A. These plots were intrinsically poorer in Fe than those treated with lesser Cu. Foliar Fe:Cu and Zn:Cu ratios were also lowest, but not below adverse levels, for the highest Cu treatment levels at sites A and B, respectively. Even the highest levels of soil Cu did not reduce N supply for, or N nutrition of, the onion crop, or alter the crop concentrations or uptakes of P, K, Ca, Mg and Mn. Key words: Copper, onions, subsidence, histosol, muck, peat


Author(s):  
J. A. Traquair ◽  
E. G. Kokko

With the advent of improved dehydration techniques, scanning electron microscopy has become routine in anatomical studies of fungi. Fine structure of hyphae and spore surfaces has been illustrated for many hyphomycetes, and yet, the ultrastructure of the ubiquitous soil fungus, Geomyces pannorus (Link) Sigler & Carmichael has been neglected. This presentation shows that scanning and transmission electron microscopical data must be correlated in resolving septal structure and conidial release in G. pannorus.Although it is reported to be cellulolytic but not keratinolytic, G. pannorus is found on human skin, animals, birds, mushrooms, dung, roots, and frozen meat in addition to various organic soils. In fact, it readily adapts to growth at low temperatures.


2014 ◽  
Vol 23 (4) ◽  
pp. 173-186 ◽  
Author(s):  
Deborah Hinson ◽  
Aaron J. Goldsmith ◽  
Joseph Murray

This article addresses the unique roles of social work and speech-language pathologists (SLPs) in end-of-life and hospice care settings. The four levels of hospice care are explained. Suggested social work and SLP interventions for end-of-life nutrition and approaches to patient communication are offered. Case studies are used to illustrate the specialized roles that social work and SLP have in end-of-life care settings.


2007 ◽  
Vol 12 (6) ◽  
pp. 5-8 ◽  
Author(s):  
J. Mark Melhorn

Abstract Medical evidence is drawn from observation, is multifactorial, and relies on the laws of probability rather than a single cause, but, in law, finding causation between a wrongful act and harm is essential to the attribution of legal responsibility. These different perspectives often result in dissatisfaction for litigants, uncertainty for judges, and friction between health care and legal professionals. Carpal tunnel syndrome (CTS) provides an example: Popular notions suggest that CTS results from occupational arm or hand use, but medical factors range from congenital or acquired anatomic structure, age, sex, and body mass index, and perhaps also involving hormonal disorders, diabetes, pregnancy, and others. The law separately considers two separate components of causation: cause in fact (a cause-and-effect relationship exists) and proximate or legal cause (two events are so closely related that liability can be attached to the first event). Workers’ compensation systems are a genuine, no-fault form of insurance, and evaluators should be aware of the relevant thresholds and legal definitions for the jurisdiction in which they provide an opinion. The AMA Guides to the Evaluation of Permanent Impairment contains a large number of specific references and outlines the methodology to evaluate CTS, including both occupational and nonoccupational risk factors and assigning one of four levels of evidence that supports the conclusion.


Author(s):  
Ammar Hameed Madi ◽  
Jawad A. Kamal Al-Shibani

This study was conducted to investigate the effect of bacterial bio-fertilization A. chroococcum and P. putide and four levels of compost (0, 1, 2, 3) tons.h-1 on the leaves content of N.P.K elements. The experiment was carried out in one of the greenhouses of the College of Agriculture - University of Al-Qadisiyah during fall season 2018-2019. It designed in accordance with the Randomized Complete Block Design (RCBD) with three replicates in sandy loam soil. The means of treatments were compared with the least significant difference (LSD) at (5)% probability level. The results present that the treatments of A. chroococcum, P. putide and compost at (3) tons.kg-1 significantly increases the leaves content of K.P.K compared to all other treatments in the flowering stage (4.970, 0.5000, and 4.930) mg.kg-1, respectively. This treatment was followed by the effect of the treatment of A. chroococcum and compost at (3) tons.kg-1, which increases the values of all traits except the leaf content of (P). Bio-fertilizer with P. putide + A. chroococcum significantly increases the leaves' content of P.


2015 ◽  
Vol 4 (2) ◽  
pp. 50-55
Author(s):  
Sandra J Nendissa ◽  
Rachel Breemer ◽  
Nikholaus Melamas

This objectives of this research were both to study and determine the best level of concentration of yeast Saccharomyces cereviseae and period of fermentation on the quality of tomi-tomi vinegar (Flacourtia inermis). A completely randomized experimental design with two factors of treatment was applied in this research. The first factor was concentration of yeast S. cereviseae having four levels of tretament, i.e.: without the addition of yeast 0.5, 1 and 1.5 g yeast. The second factor was period fermentation with 1, 2, 3, 4, and 5 weeks. The result indicated that the concentration of yeast S. cereviseae 1.5 g and period fermentation 5 week produced a good tomi-tomi vinegar with total acids 51.22%, total dissolved solids 8.35, total sugar 8.07% and pH 5.40.


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