EFFECTS OF BENZENEHEXACHLORIDE ON SOIL MICROORGANISMS: II. EXPERIMENTS WITH UREA-HYDROLYZING BACTERIA

1954 ◽  
Vol 32 (1) ◽  
pp. 10-15 ◽  
Author(s):  
P. H. H. Gray
Keyword(s):  
Soil Bacteria ◽  
Soil Microorganisms ◽  
Filler Materials ◽  
Nitrate Production ◽  
Wettable Powder ◽  
Pure Cultures ◽  
Hydrolysis Of ◽  
Solution Cultures ◽  
Hydrolysis Of Urea

Benzenehexachloride (BHC), as "Gammexane" or "Benexane 50" reduced the hydrolysis of urea by mixed and pure cultures of soil bacteria in solution cultures. It suppressed the development of urea hydrolyzing bacteria in gelatine plate cultures. The reduction or suppression was apparently due to the benzenehexachloride (and not to the "filler" materials in the wettable powder), by interference with the action of the urease, as well as by preventing growth of the bacteria; the gamma isomer had no effect. BHC did not suppress nitrate production from urea in soil.

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.

EFFECTS OF BENZENEHEXACHLORIDE ON SOIL MICROORGANISMS: I. EXPERIMENTS WITH AUTOTROPHIC BACTERIA

1954 ◽  
Vol 32 (1) ◽  
pp. 1-9 ◽  
Author(s):  
P. H. H. Gray
Keyword(s):  
Organic Matter ◽  
Soil Microorganisms ◽  
Nitrifying Bacteria ◽  
Filler Materials ◽  
Toxic Component ◽  
Autotrophic Bacteria ◽  
Mineral Soils ◽  
Reduced Toxicity ◽  
Solution Cultures ◽  
Vegetable Compost

Benzenehexachloride (BHC) and its gamma isomer were toxic against bacteria that oxidize ammonia to nitrite, and those that oxidize nitrite to nitrate, in solution media inoculated with soils. They were not toxic against nitrifying bacteria in soils nor against those of a vegetable compost in solution cultures. They were also toxic against bacteria that oxidize thiosulphate in solution cultures of mineral soils. Additional organic matter reduced toxicity of the gamma isomer. The toxic component was in the benzenehexachloride and not in the "filler" materials. The gamma isomer was less effective than some other component or combination of components of the BHC. Neither the BHC nor the gamma isomer stimulated nitrification.

scholarly journals A new mechanistic framework to predict OCS fluxes from soils

2016 ◽  
Vol 13 (8) ◽  
pp. 2221-2240 ◽  
Author(s):  
Jérôme Ogée ◽  
Joana Sauze ◽  
Jürgen Kesselmeier ◽  
Bernard Genty ◽  
Heidi Van Diest ◽  
...  
Keyword(s):  
Large Scale ◽  
Soil Microorganisms ◽  
Soil Moisture Content ◽  
Mechanistic Model ◽  
Carbonyl Sulfide ◽  
Reaction Diffusion ◽  
Global Scale ◽  
First Order ◽  
Uptake Rates ◽  
Hydrolysis Of

Abstract. Estimates of photosynthetic and respiratory fluxes at large scales are needed to improve our predictions of the current and future global CO2 cycle. Carbonyl sulfide (OCS) is the most abundant sulfur gas in the atmosphere and has been proposed as a new tracer of photosynthetic gross primary productivity (GPP), as the uptake of OCS from the atmosphere is dominated by the activity of carbonic anhydrase (CA), an enzyme abundant in leaves that also catalyses CO2 hydration during photosynthesis. However soils also exchange OCS with the atmosphere, which complicates the retrieval of GPP from atmospheric budgets. Indeed soils can take up large amounts of OCS from the atmosphere as soil microorganisms also contain CA, and OCS emissions from soils have been reported in agricultural fields or anoxic soils. To date no mechanistic framework exists to describe this exchange of OCS between soils and the atmosphere, but empirical results, once upscaled to the global scale, indicate that OCS consumption by soils dominates OCS emission and its contribution to the atmospheric budget is large, at about one third of the OCS uptake by vegetation, also with a large uncertainty. Here, we propose a new mechanistic model of the exchange of OCS between soils and the atmosphere that builds on our knowledge of soil CA activity from CO2 oxygen isotopes. In this model the OCS soil budget is described by a first-order reaction–diffusion–production equation, assuming that the hydrolysis of OCS by CA is total and irreversible. Using this model we are able to explain the observed presence of an optimum temperature for soil OCS uptake and show how this optimum can shift to cooler temperatures in the presence of soil OCS emission. Our model can also explain the observed optimum with soil moisture content previously described in the literature as a result of diffusional constraints on OCS hydrolysis. These diffusional constraints are also responsible for the response of OCS uptake to soil weight and depth observed previously. In order to simulate the exact OCS uptake rates and patterns observed on several soils collected from a range of biomes, different CA activities had to be invoked in each soil type, coherent with expected physiological levels of CA in soil microbes and with CA activities derived from CO2 isotope exchange measurements, given the differences in affinity of CA for both trace gases. Our model can be used to help upscale laboratory measurements to the plot or the region. Several suggestions are given for future experiments in order to test the model further and allow a better constraint on the large-scale OCS fluxes from both oxic and anoxic soils.

scholarly journals Discussion on the Scheme of Preparing Ammonia Gas by Hydrolysis of Urea

2019 ◽  
Vol 612 ◽  
pp. 042034
Author(s):  
Jingcheng Su ◽  
Fangming Xue ◽  
Feng Chen ◽  
Yiqing Sun ◽  
Xiuru Liu
Keyword(s):  
Ammonia Gas ◽  
Hydrolysis Of ◽  
Hydrolysis Of Urea

Analysis of Chloroxuron Technical and Its Formulations: Collaborative Study

1978 ◽  
Vol 61 (6) ◽  
pp. 1499-1503
Author(s):  
Werner Heizler ◽  
Juerg Meier ◽  
Klaus Nowak ◽  
Rolf Suter ◽  
Hans P Bosshardt
Keyword(s):  
Thin Layer ◽  
Alkaline Hydrolysis ◽  
Collaborative Study ◽  
Acid Extraction ◽  
Wettable Powder ◽  
Good Repeatability ◽  
Aoac Method ◽  
Layer Chromatography ◽  
Hydrolysis Of ◽  
Good Agreement

Abstract Chloroxuron technical and its 50% wettable powder were analyzed by 17 participants in a CIPAC collaborative study. The analytical method used involves acid extraction to remove interfering free amines, followed by alkaline hydrolysis of the extraction residue, distillation, and titration of the liberated dimethylamine. Related byproducts which may interfere are determined by semiquantitative thin layer chromatography. Results obtained from 17 government and industrial collaborators showed good repeatability within laboratories. Good agreement was also achieved between laboratories. A reproducibility of about 1.5% was obtained. The method has been adopted as an interim official CIPAC-AOAC method.

scholarly journals Screening of a Soil Bacteria Collection for the Production of Alkali Thermostable Xylanases

2018 ◽  
Vol 10 (8) ◽  
pp. 232
Author(s):  
C. R. Sampaio ◽  
C. G. S. Silva ◽  
É. C. T. Anjos ◽  
R. P. M. Fernandes ◽  
M. F. Fernandes
Keyword(s):  
Selection Criteria ◽  
Soil Bacteria ◽  
Solid Medium ◽  
Xylanase Activity ◽  
Relative Activity ◽  
Optimum Activity ◽  
Ph Values ◽  
Xylan Hydrolysis ◽  
Pure Cultures ◽  
The Stability

This work aimed to evaluate a collection of common and rare soil bacteria regarding to extracellular xylanases production and to characterize the stability in contrasting conditions of temperature and pH of these enzymes. This collection consists of 120 isolates belonging to six phyla that were subjected to screening for xylanase activity in pure cultures and in the extracellular proteic extract (EPE). The ratio between the halos diameters of xylan hydrolysis and in the colonies on solid medium (ratio H:C) was used for the evaluation of cultures as selection criteria. EPEs of isolates with highest ratios H:C were evaluated for the specific xylanases activity at 50 °C for 1 h. EPE of the three isolates with the highest potential for activity under this condition were evaluated for optimum activity, stability at 60 °C and different pH values. Twenty-two isolates showed xylanase activity under these conditions. Xylanases from TC21 and TC119 showed high relative activity at temperatures up to 70 °C and were less sensitive to changes in pH. Soil bacteria show high potential as a source of extracellular xylanases adapted to extreme pH and temperature conditions, which are required in agroindustrial processes.

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