A two-year field study and two incubation studies were conducted to evaluate incorporating urea with a urease and nitrification inhibitor to reduce N2O and N losses from fall banded fertilizer. In each year of the field experiment, five fertilizer treatments (fall banded NBPT-DCD urea, conventional urea, calcium nitrate, spring banded conventional urea and control) were applied at three sites. The effect of incorporating urease and nitrification inhibitors with urea was not consistent in our studies. The application of fall banded NBPT and DCD did not result in greater agronomic performance. Moreover, the addition of inhibitors to urea did not reduce nitrous oxide emissions in the field. The addition of inhibitors resulted in significantly less cumulative nitrous oxide emissions compared to conventional urea in only one of two laboratory experiments. In conditions where fertilizer was not generally susceptible to large losses, the effects of urease and nitrification inhibitors may not be evident.

This trial was carried out in order to elucidate factors affecting milk urea nitrogen (MUN). Twenty-five herds were selected for MUN testing. Three sampling periods were chosen. The first occurred during the months of March and April, the second during July and August, and the third during November and December 1997. A total of 2,686 samples were collected and analyzed. Two different methods were employed for MUN analysis and were referred to as the Macdonald Campus method (MUN-MAC) and the Programme d'Analyse des Troupeaux Laitiers du Quebec method (MUN-P.A.T.L.Q.). The MUN-MAC consists of an enzymatic method while the P.A.T.L.Q. method is an infra-red method. Prior to initiation of the trial, the MUN-MAC method was validated and found suitable for use in this experiment. The results demonstrated that the factors which significantly contributed to the models were the ration's net energy of lactation, season, region, somatic cell count, total dry matter, neutral detergent fiber, non-structural carbohydrates, total fat, crude protein, protein to energy ratio, starch to protein ratio, parity and days in milk. (Abstract shortened by UMI.)

The cow/calf phase of production represents a large expense in the production of beef, and efficient beef cows use fewer resources to obtain the same outcome in a sustainable environment. The objective of study 1 was to utilize a mechanistic nutrition model to estimate metabolizable energy requirement (MER) of grazing cows based on changes in cow body weight (BW) and fatness measurements (body condition score, BCS) along with calf age and BW, as well as forage quality and quantity. In addition, an energy efficiency index (EEI), computed as MER of the cow and calf divided by calf weaning BW, was used to rank cows within a herd based on their efficiency of utilizing available forage to meet their maintenance requirements and support calf growth. Data were collected from one herd of approximately 140 Santa Gertrudis cows over a four-year period, and analyzed per calving cycle, conception to weaning. The model's estimation of EEI appears to be moderately heritable and repeatable across years, and efficient cows might have greater peak milk and be leaner. In typical feedlot diets, the rates of ruminal fermentation of highly processed grains and the hydrolysis rate of urea may not match. Asynchronous utilization of carbohydrate and protein would result in some portion of the urea unknot being utilized by the ruminal microbes and ultimately the animal. The use of slow-release urea (SRU) products offers a unique opportunity to synchronize ruminal fermentation of carbohydrate with non-protein nitrogen (NPN) release rate. Two experiments were conducted to examine the impact of source, urea or SRU, and level of dietary NPN on 1) performance and carcass characteristics and 2) N balance of finishing cattle. Steers had lower initial F:G when SRU was used as the only source of feed N (treatment 3), suggesting that SRU may replace both NPN and true protein feeds in finishing cattle diets. High levels of either NPN source had greater N intake and urinary N excretion, as well as N absorption and no major differences were observed between SRU and urea, suggesting that SRU can replace urea at different levels of N intake.

Endoproteinase Glu-C (EPGIu-C, EC 3.4.21.19), an enzyme isolated from the bacteria Staphylococcus aureus, has been found to cleave specifically at the carboxyl-terminal side of glutamyl and aspartyl peptide bonds. EPGIu-C has been reported to be stable and active in the presence of common denaturants such as guanidinium chloride, urea and sodium dodecyl sulfate (Drapeau, G.R. (1977) Methods in Enzymology, 47:189-191). In order assess the denaturant stability and activity of EPGIu-C, the effect of three common protein denaturants, guanidinium chloride, urea, and sodium dodecyl sulfate (SDS) on the proteolytic activity of EPGIu-C was studied.The kinetics of the hydrolyis reaction catalyzed by EPGIu-C was determined using the chromophoric substrate N-tBOC-L-glutamic acid-a-phenyl ester (BGPE).To compare theurea is significantly greater at the higher concentrations of urea. These results suggest that a complete cleavage of proteins substrate by EPGlu-C might occur more rapidly in 8.0 M urea than in 6.0 M GuCl, since EPGlu-C will be operating at a significantly higher catalytic efficiency in the urea solution. / Department of Chemistry

A two-year field study and two incubation studies were conducted to evaluate incorporating urea with a urease and nitrification inhibitor to reduce N2O and N losses from fall banded fertilizer. In each year of the field experiment, five fertilizer treatments (fall banded NBPT-DCD urea, conventional urea, calcium nitrate, spring banded conventional urea and control) were applied at three sites. The effect of incorporating urease and nitrification inhibitors with urea was not consistent in our studies. The application of fall banded NBPT and DCD did not result in greater agronomic performance. Moreover, the addition of inhibitors to urea did not reduce nitrous oxide emissions in the field. The addition of inhibitors resulted in significantly less cumulative nitrous oxide emissions compared to conventional urea in only one of two laboratory experiments. In conditions where fertilizer was not generally susceptible to large losses, the effects of urease and nitrification inhibitors may not be evident.

No description available.

Darbo apimtis: 50 p. Jame 9-ios lentelės, 28-i paveikslai. Literatūros šaltiniai: knygų – 6, mokslinių straipsnių – 21, Internetinių šaltinių – 1. Tikslas: Nustatyti kraujyje esančio kreatinino, šlapalo bei kitų medžiagų – alaninaminotransferazės, aspartataminotransferazės ir amilazės, koncentracijų kitimus katėms sergančioms lėtiniu inkstų nepakankamumu. Metodika: 2011 – 2013 m. „Kaivanos“ smulkių gyvūnų klinikoje buvo atliktas tyrimas, kuriame dalyvavo 50 lėtiniu inkstų nepakankamumu sergančių kačių. Joms buvo atlikta kraujo biocheminių rodiklių analizė (kreatinino, šlapalo, alaninaminotransferazės, aspartataminotransferazės ir amilazės) biocheminiu kraujo analizatoriumi Refloctron Plus Roche. WinExcel programa atlikta šių duomenų stasistinė analizė, vertinanat kačių kreatinino stadijų, amžiaus, lyties, kastracijos ir veislės įtaką sergant lėtiniu inkstų nepakankamumu. Atlikta požymių koreliacinė analizė ir vienfaktorinė dispersinė analizė. . Rezultatai, išvados:  Katės lėtiniu inkstų nepakankamumu serga gana retai – 5% iš visų 1183 (100%) klinikoje apsilankiusiųjų.  Sergamumui LIN gyvūno amžius, veislė, lytis pastebimos įtakos neturi. Tačiau imliausios yra 7 – 9 m. katės.  Kreatinino koncentracija tiksliai nusako ligos sunkumą ir priklauso tik nuo inkstų pažeidimo, kiti faktoriai jo kiekio svyravimams įtakos neturi.  Sergančių IV-a LIN stadija kačių buvo nustatyta daugiausia – 18 (36%).  Šlapalo kiekis kraujyje tiesiogiai korialiuoja su LIN stadija ir kreatinino... [toliau žr. visą tekstą] / Study consist of: 50 printed pages, including 9 tables, 28 figures References: twenty eight of references were used. Objective: To identify the variations in circulating creatinine, urea and other substances - alanine aminotransferase, aspartate aminotransferase, and amylase concentration in cats suffering from chronic kidney failure. Methodics: In 2011 – 2013 years on „Kaivana“ small animal clinic a study was conducted on 50 cats who had chronic renal insufficiency. For those cats were made a blood chemistry analysis (creatinine, urea, alanine aminotransferase, aspartate aminotransferase, and amylase) with blood chemistry analyzer Refloctron Plus Roche. WinExcel program performed the statistical analysis, the assessment of feline creatinine stage, age, sex, breed and castration effect on patients with chronic renal failure. We also conducted a correlation analysis features, and one factor analysis of variance. Results, Conclusions:  Cats with chronic renal failure suffer relatively rarely - 5%.  For the incidence of CRF, animal age, breed, sex has no significant influence. However, the most receptive cats are from 7 to 9 years of life.  Creatinine concentration accurately describes the severity of the disease and depends only on kidney damage and other factors it is not affected by fluctuations in volume.  Sick-IV stage of a CRF cat was found mainly - 18 (36%).  Urea levels directly correlated with the stage of CRF and creatinine. Also Urea is an informative setting... [to full text]

Fertilizer applications of urea and triple superphosphate (TSP) suffer from low efficiency for corn production. Band or broadcast application of urea with acidic-P fertilizers may increase fertilizer efficiency. Urea and acidic-P fertilizer interactions in soil-fertilizer microsites were investigated using two Quebec soils. Adding acidic phosphates such as TSP and monoammonium phosphate (MAP) to urea reduced pH in microsites, urea hydrolysis, NH$ sb3$ volatilization, and increased soil NH$ sb4$- and NO$ sb3$-N contents. Ammonia loss decreased as P$ rm sb2O sb5$: urea-N ratios increased. Adding urea to P fertilizer increased soil pH and P sorption when using CaCl$ sb2$ as the electrolyte. Urea application increased 0.5 M NaHCO$ sb3$ extractable P. Banding urea with TSP caused dissolution of organic matter in soils, and increased P diffusion and P concentration in soil solution sampled with filter paper or in 1 M KCl extraction. Two years of field experiments demonstrated that banding urea with TSP or MAP increased soil extractable P (Mehlich-3), N and P nutrient uptake, plant growth and development of corn. Greater P fertilizer efficiencies and higher yields were achieved by banding urea-acidic P fertilizers.

During alcoholic fermentation Saccharomyces cerevisiae metabolizes L-arginine to ornithine and urea. S. cerevisiae can metabolize urea through the action of urea amidolyase, encoded by the DUR1,2 gene; however, DUR1,2 is subject to nitrogen catabolite repression (NCR) in the presence of high quality nitrogen sources during fermentation. Being cytotoxic at high concentrations, urea is exported into wine where it spontaneously reacts with ethanol, and forms the carcinogen ethyl carbamate (EC). Urea degrading yeast strains were created by integrating a linear cassette containing the DUR1,2 gene under the control of the S. cerevisiae PGK1 promoter and terminator signals into the URA3 locus of the Sake yeast strains K7 and K9. The ‘self-cloned’ strains K7EC- and K9EC- produced Sake wine with 68% less EC. The Sake strains K7EC- and K9EC- did not efficiently reduce EC in Chardonnay wine due to the evolutionary adaptation of said strains to the unique nutrients of rice mash; therefore, the functionality of engineered yeasts must be tested in their niche environments as to correctly characterize new strains. S. cerevisiae possesses an NCR controlled high affinity urea permease (DUR3). Urea importing yeast strains were created by integrating a linear cassette containing the DUR3 gene under the control of the PGK1 promoter and terminator signals into the TRP1 locus of the yeast strains K7 (Sake) and 522 (wine). In Chardonnay wine, the urea importing strains K7D3 and 522D3 reduced EC by 7% and 81%, respectively; reduction by these strains was equal to reduction by the urea degrading strains K7EC- and 522EC-. In Sake wine, the urea degrading strains K7EC- and 522EC- reduced EC by 87% and 84% respectively, while the urea importing strains K7D3 and 522D3 were significantly less capable of reducing EC (15% and 12% respectively). In Chardonnay and Sake wine, engineered strains that constitutively co-expressed DUR1,2 and DUR3 did not reduce EC more effectively than strains in which either gene was expressed solely. Uptake of 14C-urea under non-inducing conditions was enhanced in urea importing strains; parental strains failed to incorporate any 14C-urea thus confirming the functionality of the urea permease derived from the integrated DUR3 cassette.

Thesis (Ph. D.)--University of Nevada, Reno, 2007. / "August, 2007." Includes bibliographical references (leaves 150-154). Online version available on the World Wide Web.