EFFECTS OF CATECHOL AND P-BENZOQUINONE ON THE HYDROLYSIS OF UREA AND ENERGY BARRIERS OF UREASE ACTIVITY IN SOILS

1984 ◽  
Vol 64 (1) ◽  
pp. 51-60 ◽  
Author(s):  
J. S. TOMAR ◽  
A. F. MacKENZIE
Keyword(s):  
Activation Energy ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Key Words ◽  
Urease Activity ◽  
Urea Hydrolysis ◽  
Urease Inhibitors ◽  
Soil Urease ◽  
Hydrolysis Of ◽  
Hydrolysis Of Urea

The effects of the urease inhibitors, catechol and p-benzoquinone, and temperature on the hydrolysis of urea in five soils were investigated in a laboratory study. Urea hydrolysis decreased significantly with the amount of inhibitors applied and increased significantly with each 5 °C increase in temperature from 5 to 25 °C. The effectiveness of inhibitors generally decreased with increases in temperature from 5 to 25 °C. The correlation of hydrolysis of urea with organic matter contents of the soils was highly significant (r = 0.67** to 0.86**). Both catechol and p-benzoquinone tended to increase the energies and entropies of activation of soil urease and the effect was enhanced with a decrease in soil organic matter. It is suggested that an increase in the activation energy of the soil urease as a result of inhibitor use was related to an increase in the effectiveness of the inhibitor. Key words: Urease inhibitors, urea hydrolysis, energy of activation

EFFECT OF SOIL ORGANIC MATTER OXIDATION ON THE COLLAPSE OF VERMICULITE

1985 ◽  
Vol 65 (3) ◽  
pp. 593-597 ◽  
Author(s):  
N. M. MILES ◽  
M. SCHNITZER ◽  
C. R. DE KIMPE
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Key Words ◽  
Mixed Layer ◽  
Ir Spectrum ◽  
X Ray Diffraction ◽  
X Ray ◽  
Organic Matter Oxidation ◽  
Ir Spectrophotometry ◽  
Complete Collapse

Oxidation of organic matter with H2O2 produced substantial amounts of NH3 which was then fixed by vermiculite, causing partial or complete collapse and converting the mineral to a mica-like product. The collapse of the mineral was indicated by shifts in the 001 spacing from 1.476 to 1.030 nm and the appearance of a well-defined band at 1430 cm−1 in the IR spectrum, indicative of the presence of NH4+ in the interlayer positions of the clay. Our data suggest that: (a) the transformation of vermiculite to mica during H2O2 oxidation may result in underestimation of the vermiculite content of soils by XRD, and (b) the wide occurrence of mixed-layer minerals in soils may in part have resulted from the fixation of NH3 liberated from the microbial mineralization of organically bound N. Key words: Ammonia, X-ray diffraction, IR spectrophotometry, mixed-layer minerals, H2O2 pretreatment

The differentiation of Trichophyton rubrum and T. mentagrophytes by use of Christensen's urea broth

1971 ◽  
Vol 17 (7) ◽  
pp. 911-913 ◽  
Author(s):  
Julius Kane ◽  
J. B. Fischer
Keyword(s):  
Urease Activity ◽  
Trichophyton Rubrum ◽  
Agar Medium ◽  
Phenol Red ◽  
Depressing Effect ◽  
Fluid Medium ◽  
Maximum Change ◽  
Pure Cultures ◽  
Hydrolysis Of ◽  
Hydrolysis Of Urea

A comparison of the urease activity of 56 strains of T. rubrum and 64 strains of T. mentagrophytes on Christensen's urea medium with and without agar incubated 7 days at 28 °C showed that characteristic and consistent results are produced on this medium without agar. In the fluid medium T. mentagrophytes caused a rise in pH, resulting in a maximum change of the phenol red, and T. rubrum produced no change. The depressing effect of agar on the hydrolysis of urea was demonstrated. On the agar medium 9 (18.8%) of 48 strains of T. mentagrophytes and 3 (6.2%) of 48 strains of T. rubrum produced doubtful results. It is important that pure cultures be used for the test.

Soil science on the Canadian prairies - Peering into the future from a century ago

2001 ◽  
Vol 81 (4) ◽  
pp. 489-503 ◽  
Author(s):  
H H Janzen
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Key Words ◽  
Crop Rotation ◽  
Soil Science ◽  
Good Time ◽  
Grassland Soils ◽  
Canadian Prairies ◽  
The Future

Now, as a new century begins, may be a good time to reflect on the future of Soil Science on the Canadian prairies. One way to do that is to step back about one hundred years, to the turn of the previous century when our grassland soils were first cultivated. What questions perplexed scientists then? And how did they look for answers? My objective is to listen for our forebears’ thoughts in their writings, now largely buried. From this historical vantage may emerge insights, not only into where our science has been, but also into where it might yet go. Key words: Soil organic matter, crop rotation, grassland soils, history

Soil Enzyme Activities of Wetland in Liangzi Lake

2014 ◽  
Vol 700 ◽  
pp. 235-238
Author(s):  
Han Feng Xiong
Keyword(s):  
Organic Matter ◽  
Enzyme Activity ◽  
Soil Organic Matter ◽  
Phosphatase Activity ◽  
Urease Activity ◽  
Soil Enzyme ◽  
Soil Enzyme Activity ◽  
Wetland Soil ◽  
Positive Correlation ◽  
Change Trend

Soil enzyme activity is closely related to ecosystem course and function.Tendency and intensity of different biochemical course carried on in the soil was reflected by enzyme activity. This paper deals with the soil enzyme activity, content of organic matter, N,P 'and the relation of the enzyme activity with soil organic matter, N,P in soil of Liangzi Lake wetland by soil samples analyzed. The results shows that in the wetland soil,the urease activity is 0.397-0.652 mg/g ;the phosphatase activity is phenol6.52-11.53 mg/g; The activity of Cellulase in the soil is 0.397 - 0.652 mg/g. The change trend of Cellulase and phosphatase activity throughout the year is summer > autumn > winter > spring. The change trend of urinary enzyme throughout the year is summer > spring > autumn > winter. There is notably positive correlation between the urease activity and soil available nitrogen. There is notably positive corelation between the phosphatase activity and soil available P in the paddy field.There is notably positive correlation between the Cellulase activity and soil organic matter.

scholarly journals Urease testing and yeast taxonomy

1987 ◽  
Vol 33 (5) ◽  
pp. 396-404 ◽  
Author(s):  
J. Leland Booth ◽  
H. S. Vishniac
Keyword(s):  
Urease Activity ◽  
Ethylenediaminetetraacetic Acid ◽  
Chelating Agent ◽  
Maximal Activity ◽  
Urea Hydrolysis ◽  
Basidiomycetous Yeasts ◽  
Urease Production ◽  
Ascomycetous Yeasts ◽  
Hydrolysis Of ◽  
By Products

When urease production was assayed by the hydrolysis of [14C]urea, all basidiomycetous yeasts tested, including the Cryptococcus vishniacii complex (previously reported urease negative), produced significant amounts of 14CO2. The Schizosaccharo-mycetaceae were the only urease-positive ascomycetous yeasts tested. Yarrowia lipolytica was urease negative. The stoichiometry of [14C]urea hydrolysis paralleled by Roberts' rapid urea hydrolysis (RUH) test indicated that causes of anomalous results in conventional urease testing include acidification and alkalinization of the test medium by products of endogenous metabolism and autolysis rather than urease activity. Anomalous results also occurred when cells were grown on media containing the chelating agent ethylenediaminetetraacetic acid (EDTA) prior to RUH. The addition of EDTA to a complex natural medium inhibited urease production in all yeasts reportedly growing at 35 °C (and all other yeasts tested), except Filobasidiella (Cr.) neoformans var. neoformans (NIH 12). The RUH test could differentiate at the varietal level: Fil. (Cr.) neoformans var. neoformans was about 10 times more resistant to EDTA in media used for the growth of cells prior to RUH testing than was Fil. neoformans var. bacillispora (Cr. neoformans var. gattii) (NIH 191). Urease production by Fil. neoformans var. bacillispora was specifically restored to half maximal activity by the addition of 22 μM Ni+2 (as NiCl2) to a growth medium containing 0.100 mM EDTA.

EFFECTS OF INTENSIVE VEGETABLE PRODUCTION ON THE HYDROLYZABLE CARBON, NITROGEN AND SULPHUR OF A BRITISH COLUMBIA HUMISOL

1990 ◽  
Vol 70 (4) ◽  
pp. 621-628 ◽  
Author(s):  
B. M. OLSON ◽  
L. E. LOWE
Keyword(s):  
Organic Matter ◽  
Key Words ◽  
Organic Soil ◽  
Hydriodic Acid ◽  
Soil Samples ◽  
Weight Basis ◽  
Vegetable Production ◽  
Total N ◽  
Hydrolysis Of ◽  
Soil Weight

Acid hydrolysis was used to examine organic matter (OM), C, N and S in adjacent uncultivated and cultivated (40 yr) sections of a humisol. Paired soil samples were collected along two transects, both of which included deep organic soil and an exposed mineral ridge. About one-third of the OM was hydrolyzed. Cultivation had no effect on hydrolysis of the deep organic soil, whereas the amount hydrolyzed was significantly reduced by 4.1% in the ridge samples. Total C hydrolyzed ranged from 22.8 to 26.9% with no effect caused by cultivation or transect position relative to the ridge. In contrast, 71.1–80.4% of total N and 39.1 to 49.3% of total S were hydrolyzed. Cultivation significantly reduced the proportion of total N hydrolyzed in the deep organic soil and the proportion of total S hydrolyzed in both the deep organic soil and the ridge sections. On a total soil weight basis, cultivation reduced the amount of OM, C, N and S hydrolyzed in the ridge samples by 43, 38, 44 and 39%, respectively, but had much less effect on the deep organic soil samples. For the most part the distribution of N forms was similar for the four transect sections. Most of the S hydrolyzed was in the hydriodic acid-reducible sulphur (HI-S) form. The hydrolyzates from the cultivated soil samples had higher C-S:HI-S ratios. The amount of S hydrolyzed in the OM was not affected by cultivation, whereas residue-S was increased by 35.1 to 64.7%. The problems encountered with S hydrolysis analysis were discussed. Key words: Cultivation, humisol, hydrolysis, organic matter, carbon, nitrogen, sulphur

ACTION OF PROTEOLYTIC ENZYMES ON SOIL ORGANIC MATTER

1970 ◽  
Vol 50 (2) ◽  
pp. 233-241 ◽  
Author(s):  
F. J. SOWDEN
Keyword(s):  
Amino Acids ◽  
Organic Matter ◽  
Amino Acid ◽  
Soil Organic Matter ◽  
Acid Hydrolysis ◽  
Leucine Aminopeptidase ◽  
Proteolytic Enzymes ◽  
Complexing Agent ◽  
Organic Matter Fractions ◽  
Hydrolysis Of

The amino acids set free by proteolytic enzymes were determined with an amino acid analyzer. Soil and enzyme blanks were subtracted. Pronase released 2 to 10% of the aspartic acid + asparagine, threonine, serine, glutamic acid + glutamine, glycine, lysine and histidine in some fractions of soil organic matter along with 15–35% of the alanine, valine, isoleucine, leucine, tyrosine, phenylalanine and arginine. There was no release of proline, ornithine or ammonia. When the pronase hydrolysate was treated with leucine amino-peptidase, 15% of the proline was released, the yield of glycine was raised from 2 to 14% and the amount of the acidic amino acids was also higher. Acid hydrolysis of the pronase hydrolysate also released more amino acid material but the blanks were much higher than with leucine aminopeptidase. The results suggested that more than half of the aspartic and glutamic acids found on acid hydrolysis were present in the soil organic matter fractions as asparagine and glutamine. The action of pronase on the organic matter of the intact soil was slight, even in the presence of a complexing agent. Papain released very little amino acid material from organic matter fractions, but leucine aminopeptidase or HCl hydrolysis of the papain hydrolysate released about 10% of the amino acid of the fraction, indicating that significant amounts of peptides were formed on papain treatment.

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