Urease inhibitors

Several alternatives are used to reduce ammonia elimination. Applied in relatively small quantities, urease inhibitors such as A-(n-butyl) thiophosphoric acid triamide reduce the rate of microbial hydrolysis of urea and increase its efficiency as a fertilizer (Manahan, 2005). Ammonia volatilization could also be reduced using a mixture of urea with tropical peat soil or free humic substances, such as humic and fulvic acids, isolated from peat soils (Bernard et al., 2009). Another application of green technologies is the use of thermal polyaspartate, a product formed by the condensation and base treatment of a natural compound, aspartic acid. This has been found to be effective in stimulating plant uptake of fertilizer thus reducing the amount of fertilizer required (Manahan, 2005). 

Nicotine hydroxamic acid is a urease inhibitor which reduces ammonia formation in the intestine. This substance has no systemic side effects. In a controlled double-blind study, it proved to be superior to treatment with neomycin (C. Hirayama et at, 1982). 

Certain bacterial strains arc resistant to the action of mcthenamine because they elaborate urease, an enzyme that hydrolyzes urea to form ammonia. The resultant high urinary pH prevents the activation uf methenaminc. rendering it inc fcetivc. This problem can be overcome by the euadministra-tion uf the urease inhibitor acctohydroxamic acid (Litho.stat). 

Fluress fluorescein oxybuprocaine. flurofamide [inn, usan] (EU 4534) is a benzamide, a UREASE INHIBITOR. 

In vitro studies using slurries of cattle manure and urine indicated that addition of the urease inhibitor N-(ft-butyl) thiophosphoric triamide (NBPT) can extend the survival of coliform bacteria in the manure (Varel et ah, 2007a). However, coliform bacteria were rapidly eliminated when the plant oil thymol was used in combination with NBPT in the manure slurries (Varel et ah, 2007a). Similarly, the application of NBPT with the plant oil extracts of linalool and pine oil on surfaces of feedlot pens... 

Varel, V. H., Nienaber, J. A., and Freetly, H. C. (1999). Conservation of nitrogen in cattle feedlot waste with urease inhibitors. /. Anim. Sci. 77,1162-1168. 

Varel, V. H., Wells, J. E., and Miller, D. N. (2007a). Combination of a urease inhibitor and a plant essential oil to control coliform bacteria, odour production and ammonia loss from cattle waste. J. Appl. Microbiol. 102,472-477. 

The basic component of tiie erqimimental system applied to this study was an absorbent material normally used in personal hygiene articles. In principle tiiis would be loose or bonded cellulose flufi possibly blen with cross-linked sodium polyacrylate granules (known as superabsorbent polymer, SAP) for enhanced liquid capacity. Cellulose fibers or whole composites served as carriers of known and potmitial urease inhibitors. These substances were physically attached to the absoibent core by exhaustion fiom their solutions and subsequent drying of the substrates. A few examples of materials treated this... 

A number of known and potential urease inhibitors were screened as candidates fiir treating cellulose-based absorbent systems. Acetohydroxamk acid (AHA) was one die examples, This coDqmund is used clinically to dissolve struvite stones [5], An AHA molecule has a shape which fits very well to tlw active site of urease, therefore it can compete effectively against urea to form a stable complex with file em me. This inhibitor is watm -soluble and can be easily ai lied to a fiber-based substrate. Fw this purpose we chose Vizcnb 3905, a Buckeye-m airlaid nonwoven. The latter matoial contained SAP particles, had a basis weight of 2S0gfei and a web density of0.094 g/ca. ... 

Our studies with urease inhibitor-modified composites indicated that the new materials were able to maintain the slightly acid pH on the surface of the absorbent pad containing urine. Healthy skin has its own pH at a level which is somewhat lower than neutral. This condition ensures the stability of natural oil layer present on the skin and reduces the risk of microbial infections and irritations. 

Figure 7. Surface pH on pads made mdi urease inhibitor treated cellulose fluff.

The aim of this paper was to report the results of our studies on the modification of cellulose and cellulose-based composites with urease inhibitors. The obtained data support our suggestion that the new technology is a simple and effective way of controlling ammonia odor caused by the decomposition of urine. Another seemingly important benefit of this approach is the ability of the modified systems to maintain the pH at a level benign to skin. In addition to that, the evidence bas on our lab data suggests that the applied treatment not only retards the emission of ammonia but can also help reduce other odors typically related to menses and sweat. 

K Phillips, D J Munster, R A AUardyce and P F Bagshaw, Antibacterial actirm of the urease inhibitor acetohydroxamic acid on helicobacter pylori , J Clin Piahot, 1993 46(4)... 

M D Sweidloff, J F Kolc, M M Rogic and L L Hmbickstni, Phosphoroamide urease inhibitors and urease inhibited urea based fertilizer compositions, US Patent Office, Pat No... 

Structurally diversified heterocycles and related privileged scaffolds as potential urease inhibitors 13APL423. 

Recently, urea and urease inhibitor Af-(n-butyl) thiophosphoric triamide ( BTPT) were used to modify wheat straw-soy flour particleboards. Boric and citric acid, along sodium hypophosphite monohydrate, were used to modify soy carbohydrates. Particleboard bonded by urea and high concentrations of n BTPT-treated soy flour showed improved mechanical properties, whereas that bonded by boric acid-treated soy flour had better water resistance. The adhesive made from soy flour treated with 1.5M urea, 0.4 per cent n BTPT, 7 per cent CA, 4 pa- cent NaH2P02, 3 per cent boric acid, and 1.85 per cent NaOH, produced particleboard with the maximum mechanical strength and water resistance [57]. 

Urease Inhibitor (Australia) - Complex chemical substance that has the effect of temporarily preventing the activity of the soil enzyme urease. 

Kuhler TC, Fryklund J, Bergman NA, et al. Structure-activity relationship of omeprazole and analogues as Helicobacter pylori urease inhibitors. J Med Chem 1995 38 4906-4916. 

MATZEL W., HEBER R., ACKERMANN W. and TESKE W. 1978. Ammonia losses in urea fertilizing. 3. Effect of urease inhibitors. on ammonia volatilization. Archiv fur Acker- und Pflanzenbau und Bodenkunde, 22, 185-191. 

Khan WN, Lodhi MA, Ali I, Azhar-Ul-Haq, Malik A, Bilal S, Gul R, Choudhary MI. New natural urease inhibitors from Ranunculus repens. J. Enzyme Inhib. Med. Chem. 2006 21(1) 17-19. 

Winkler et al. (1985) have described crude and partially purified enzyme preparations from soybean seed coats which catalyze the production of NH4+, CO2, and labile glyoxylate derivatives from ALA. The reaction occurs in the presence of phenyl phosphordiamidate, a potent urease inhibitor, thus supporting an ALA amidohydrolase type of reaction. The enzyme activity had a of... 

Hydrolysis of urea is catalyzed by urease, an enzyme that can survive extracellularly in organic matter-clay soil complexes the reaction can proceed rapidly in warm, moist soils containing large amounts of the enzyme. Wider use of urease inhibitors (phosphoryl di- and triamides) may eventually reduce large ammonia volatilization losses see Byrnes, B. H., and... 

J. R. Freney. 1995. Recent developments on the use of urease inhibitors in the tropics. Fertilizer Research 42 251-259. 

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