Rapid urease test (RUT) for evaluation of urease activity in oral bacteria in vitro and in supragingival dental plaque ex vivo.

Science.gov (United States)

Dahlén, Gunnar; Hassan, Haidar; Blomqvist, Susanne; Carlén, Anette

2018-05-18

Urease is an enzyme produced by plaque bacteria hydrolysing urea from saliva and gingival exudate into ammonia in order to regulate the pH in the dental biofilm. The aim of this study was to assess the urease activity among oral bacterial species by using the rapid urease test (RUT) in a micro-plate format and to examine whether this test could be used for measuring the urease activity in site-specific supragingival dental plaque samples ex vivo. The RUT test is based on 2% urea in peptone broth solution and with phenol red at pH 6.0. Oral bacterial species were tested for their urease activity using 100 μl of RUT test solution in the well of a micro-plate to which a 1 μl amount of cells collected after growth on blood agar plates or in broth, were added. The color change was determined after 15, 30 min, and 1 and 2 h. The reaction was graded in a 4-graded scale (none, weak, medium, strong). Ex vivo evaluation of dental plaque urease activity was tested in supragingival 1 μl plaque samples collected from 4 interproximal sites of front teeth and molars in 18 adult volunteers. The color reaction was read after 1 h in room temperature and scored as in the in vitro test. The strongest activity was registered for Staphylococcus epidermidis, Helicobacter pylori, Campylobacter ureolyticus and some strains of Haemophilus parainfluenzae, while known ureolytic species such as Streptococcus salivarius and Actinomyces naeslundii showed a weaker, variable and strain-dependent activity. Temperature had minor influence on the RUT reaction. The interproximal supragingival dental plaque between the lower central incisors (site 31/41) showed significantly higher scores compared to between the upper central incisors (site 11/21), between the upper left first molar and second premolar (site 26/25) and between the lower right second premolar and molar (site 45/46). The rapid urease test (RUT) in a micro-plate format can be used as a simple and rapid method to test urease

Poly(acrylonitrile)chitosan composite membranes for urease immobilization.

Science.gov (United States)

Gabrovska, Katya; Georgieva, Aneliya; Godjevargova, Tzonka; Stoilova, Olya; Manolova, Nevena

2007-05-10

(Poly)acrylonitrile/chitosan (PANCHI) composite membranes were prepared. The chitosan layer was deposited on the surface as well as on the pore walls of the base membrane. This resulted in the reduction of the pore size of the membrane and in an increase of their hydrophilicity. The pore structure of PAN and PANCHI membranes were determined by TEM and SEM analyses. It was found that the average size of the pore under a selective layer base PAN membrane is 7 microm, while the membrane coated with 0.25% chitosan shows a reduced pore size--small or equal to 5 microm and with 0.35% chitosan--about 4 microm. The amounts of the functional groups, the degree of hydrophilicity and transport characteristics of PAN/Chitosan composite membranes were determined. Urease was covalently immobilized onto all kinds of PAN/chitosan composite membranes using glutaraldehyde. Both the amount of bound protein and relative activity of immobilized urease were measured. The highest activity (94%) was measured for urease bound to PANCHI2 membranes (0.25% chitosan). The basic characteristics (pH(opt), pH(stability), T(opt), T(stability), heat inactivation and storage stability) of immobilized urease were determined. The obtained results show that the poly(acrylonitrile)chitosan composite membranes are suitable for enzyme immobilization.

STRUCTURAL ORGANIZATION OF BACTERIAL UREASES

Directory of Open Access Journals (Sweden)

Lisnyak YuV

2016-09-01

Full Text Available This brief review concerns the basic principles of structural organization of multi-subunit bacterial ureases and formation of their quaternary structure. Urease is a nickel-containing enzyme (urea amidohydrolase, ЕС 3.5.1.5 that catalyses the hydrolysis of urea to get ammonia and carbamate which then decomposes with water to get ammonia and carbon dioxide. Urease is produced by bacteria, fungi, yeast and plants. On the basis of similarities in amino acid sequences, ureases assumed to have a similar structure and conservative catalytic mechanism. Within past two decades bacterial ureases have gained much attention in research field as a virulence factor in human and animal infections. The first crystal structure of urease has been determined for that from Klebsiella aerogenes. The native enzyme consists of three subunits, UreA (α-chain, UreB (β-chain and UreC (γ-chain, and contains four structural domains: two in α-chain (α-domain 1 and α-domain-2, one in β- and one in γ-chain. These three chains form a T-shaped heterotrimer αβγ. Three αβγ heterotrimers form quaternary complex (αβγ3. In case of Helicobacter pilori, the analogous trimers of corresponding dimeric subunits (αβ3 form tetrameric structure ((αβ34 in which four trimers are situated at the vertexes of the regular triangle pyramid. Active center is located in α-domain 1 and contains two atoms of nickel coordinated by residues His134, His136, carboxylated Lys217, His 246, His272 and Asp360, as well as residues involved in binding (His219 and catalysis (His320. Active site is capped by a flap that controls substrate ingress to and product egress from the dinickel center. Urease requires accessory proteins (UreD, UreF, UreG and UreE for the correct assembly of their Ni-containing metallocenters. The accessory proteins UreD, UreF, and UreG sequentially bind to the apoprotein (UreABC3 to finally form (UreABC-UreDFG3 activation complex. UreE metallochaperone delivers

Soybean roots retain the seed urease isozyme synthesized during embryo development

International Nuclear Information System (INIS)

Torisky, R.S.; Polacco, J.C.

1990-01-01

Roots of young soybean plants contain two urease isozymes which are separable by hydroxyapatite chromatography. These two urease species (HAP1 and HAP2) differ in: (1) native gel electrophoretic mobility, (2) pH optima, and (3) recognition by a monoclonal antibody specific for the embryo-specific urease. By these parameters HAP1 is similar to the abundant embryo-specific urease isozyme while HAP2 resembles the ubiquitous urease, found in all soybean tissues previously examined (embryo, seed coat, cultured cells). Roots of mutant soybean plants lacking the seed urease contain no HAP1 urease activity, whereas roots of mutants lacking the ubiquitous urease contain no HAP2 urease activity. However, adventitious roots generated from cuttings of any urease genotype lack HAP1 urease activity. Furthermore, [ 35 S] methionine labelling shows no de novo synthesis of the HAP1 urease in the root, and total root HAP1 urease activity decreases sharply following germination. We conclude: (1) HAP1 is a remnant of the seed urease accumulated in the embryonic root axis during seed development, and (2) HAP2 is ubiquitous urease synthesized de novo in the root

Cross-Reactivity of Polyclonal Antibodies against Canavalia ensiformis (Jack Bean) Urease and Helicobacter pylori Urease Subunit A Fragments.

Science.gov (United States)

Kaminski, Zbigniew Jerzy; Relich, Inga; Konieczna, Iwona; Kaca, Wieslaw; Kolesinska, Beata

2018-01-01

Overlapping decapeptide fragments of H. pylori urease subunit A (UreA) were synthesized and tested with polyclonal antibodies against Canavalia ensiformis (Jack bean) urease. The linear epitopes of UreA identified using the dot blot method were then examined using epitope mapping. For this purpose, series of overlapping fragments of UreA, frameshifted ± four amino acid residues were synthesized. Most of the UreA epitopes which reacted with the Jack bean urease polyclonal antibodies had been recognized in previous studies by monoclonal antibodies against H. pylori urease. Fragments 11 - 24, 21 - 33, and 31 - 42 were able to interact with the Jack bean urease antibodies, giving stable immunological complexes. However, the lack of recognition by these antibodies of all the components in the peptide map strongly suggests that a non-continuous (nonlinear) epitope is located on the N-terminal domain of UreA. © 2018 Wiley-VHCA AG, Zurich, Switzerland.

Biosynthesis of the Urease Metallocenter*

Science.gov (United States)

Farrugia, Mark A.; Macomber, Lee; Hausinger, Robert P.

2013-01-01

Metalloenzymes often require elaborate metallocenter assembly systems to create functional active sites. The medically important dinuclear nickel enzyme urease provides an excellent model for studying metallocenter assembly. Nickel is inserted into the urease active site in a GTP-dependent process with the assistance of UreD/UreH, UreE, UreF, and UreG. These accessory proteins orchestrate apoprotein activation by delivering the appropriate metal, facilitating protein conformational changes, and possibly providing a requisite post-translational modification. The activation mechanism and roles of each accessory protein in urease maturation are the subject of ongoing studies, with the latest findings presented in this minireview. PMID:23539618

Reduction of Urease Activity by Interaction with the Flap Covering the Active Site

Science.gov (United States)

Macomber, Lee; Minkara, Mona S.; Hausinger, Robert P.; Merz, Kenneth M.

2015-01-01

With the increasing appreciation for the human microbiome coupled with the global rise of antibiotic resistant organisms, it is imperative that new methods be developed to specifically target pathogens. To that end, a novel computational approach was devised to identify compounds that reduce the activity of urease, a medically important enzyme of Helicobacter pylori, Proteus mirabilis, and many other microorganisms. Urease contains a flexible loop that covers its active site; Glide was used to identify small molecules predicted to lock this loop in an open conformation. These compounds were screened against the model urease from Klebsiella aerogenes and the natural products epigallocatechin and quercetin were shown to inhibit at low and high micromolar concentrations, respectively. These molecules exhibit a strong time-dependent inactivation of urease that was not due to their oxygen sensitivity. Rather, these compounds appear to inactivate urease by reacting with a specific Cys residue located on the flexible loop. Substitution of this cysteine by alanine in the C319A variant increased the urease resistance to both epigallocatechin and quercetin, as predicted by the computational studies. Protein dynamics are integral to the function of many enzymes; thus, identification of compounds that lock an enzyme into a single conformation presents a useful approach to define potential inhibitors. PMID:25594724

A New Urease Inhibitor from Viola betonicifolia

Directory of Open Access Journals (Sweden)

Naveed Muhammad

2014-10-01

Full Text Available Urease has attracted much attention, as it is directly involved in the formation of infection stones and contributes to the pathogenesis of urolithiasis, pyelonephritis, ammonia and hepatic encephalopathy, hepatic coma and urinary catheter encrustation. Moreover, urease is the major cause of pathologies induced by H. pylori, such as gastritis and peptic ulcer. In the present work, the new natural compound, 3-methoxydalbergione, was isolated from Viola betonicifolia. A mechanistic study of this compound as a natural urease inhibitor was performed by using enzyme kinetics and docking studies. 3-Methoxydalbergione could be considered as a lead molecule for drugs useful in the urease associated diseases.

Fluorimetric urease inhibition assay on a multilayer microfluidic chip with immunoaffinity immobilized enzyme reactors.

Science.gov (United States)

Zhang, Qin; Tang, Xiuwen; Hou, Fenghua; Yang, Jianping; Xie, Zhiyong; Cheng, Zhiyi

2013-10-01

We fabricated a three-layer polydimethylsiloxane (PDMS)-based microfluidic chip for realizing urease inhibition assay with sensitive fluorescence detection. Procedures such as sample prehandling, enzyme reaction, reagent mixing, fluorescence derivatization, and detection can be readily carried out. Urease reactors were prepared by adsorption of rabbit immunoglobulin G (IgG) and immunoreaction with urease-conjugated goat anti-rabbit IgG. Acetohydroxamic acid (AHA) as a competitive inhibitor of urease was tested on the chip. Microfluidically generated gradient concentrations of AHA with substrate (urea) were loaded into urease reactors. After incubation, the produced ammonia was transported out of reactors and then reacted with o-phthalaldehyde (OPA) to generate fluorescent products. Urease inhibition was indicated by a decrease in fluorescence signal detected by microplate reader. The IC50 value of AHA was determined and showed good agreement with that obtained in microplate. The presented device combines several steps of the analytical process with advantages of low reagent consumption, reduced analysis time, and ease of manipulation. This microfluidic approach can be extended to the screening of inhibitory compounds in drug discovery. Copyright © 2013 Elsevier Inc. All rights reserved.

Urease activity as a risk factor for caries development in children during a three-year study period: a survival analysis approach

Science.gov (United States)

Morou-Bermudez, E; Elias-Boneta, A; Billings, RJ; Burne, RA; Garcia-Rivas, V; Brignoni-Nazario, V; Suárez-Pérez, E

2011-01-01

Recent cross-sectional studies suggest that reduced ability to generate alkali via the urease pathway in dental plaque may be an important caries risk factor, but it has not been assessed prospectively. OBJECTIVE To evaluate the effect of plaque and saliva urease activity on the risk for developing new caries over a three-year period in children. METHODS A panel of 80 children, three to six years of age at recruitment, was followed prospectively for three years. Plaque urease activity, saliva urease activity and dental caries were measured every six months. Survival analysis methodology was used to evaluate the effect of urease on caries development during the study period adjusted for gender, age, baseline caries levels, sugar consumption, amount of plaque, and mutans streptococci levels. RESULTS The risk for developing new caries increased in a dose-responsive manner with increasing levels of urease activity in saliva (adjusted HRQ4 vs. Q1: 4.98; 95%CI: 1.33, 18.69) and with decreasing urease activity in plaque (adjusted HRQ4 vs. Q1: 0.29; 95%CI: 0.11, 0.76). Multiple measurements of urease activity were conducted to overcome the variability of urease activity in this study. Baseline caries and mutans streptococci in saliva were also important predictors of caries risk. CONCLUSIONS Increased urease activity in saliva can be an indicator of increased caries risk in children, while increased urease activity in plaque may be associated with reduced caries risk. The reproducibility of urease measurements must be improved before these findings can be further tested and clinically applied. PMID:21784411

Dihydropyrimidine based hydrazine dihydrochloride derivatives as potent urease inhibitors.

Science.gov (United States)

Khan, Ajmal; Hashim, Jamshed; Arshad, Nuzhat; Khan, Ijaz; Siddiqui, Naureen; Wadood, Abdul; Ali, Muzaffar; Arshad, Fiza; Khan, Khalid Mohammed; Choudhary, M Iqbal

2016-02-01

Four series of heterocyclic compounds 4-dihydropyrimidine-2-thiones 7-12 (series A), N,S-dimethyl-dihydropyrimidines 13-18 (series B), hydrazine derivatives of dihydropyrimidine 19-24 (series C), and tetrazolo dihydropyrimidine derivatives 25-30 (series D), were synthesized and evaluated for in vitro urease inhibitory activity. The series B-D were first time examined for urease inhibition. Series A and C were found to be significantly active with IC50 values between 34.7-42.9 and 15.0-26.0 μM, respectively. The structure-activity relationship showed that the free S atom and hydrazine moiety are the key pharmacophores against urease enzyme. The kinetic studies of the active series A (7-12) and C (19-24) were carried out to determine their modes of inhibition and dissociation constants Ki. Compounds of series A (7-12) and series C (19-24) showed a mixed-type of inhibition with Ki values ranging between 15.76-25.66 and 14.63-29.42 μM, respectively. The molecular docking results showed that all the active compounds of both series have significant binding interactions with the active sites specially Ni-ion of the urease enzyme. Cytotoxicity of all series A-D was also evaluated against mammalian mouse fibroblast 3T3 cell lines, and no toxicity was observed in cellular model. Copyright © 2016 Elsevier Inc. All rights reserved.

Characteristics of Immobilized Urease on Grafted Alginate Bead Systems

Directory of Open Access Journals (Sweden)

Enas N. Danial

2015-04-01

Full Text Available This study evaluated the biological importance of immobilized urease enzyme over the free urease. The support material used for urease immobilization was alginate. Generally, the immobilization of urease in alginate gel showed a marked increase in Km and Vmax. However, the immobilized urease showed higher thermal stability than that of free enzyme. The rate of thermal inactivation of the immobilized enzyme decreased due to entrapment in gel matrix. Also, the activity of the immobilized urease was more stable in retention than that of the free enzyme during the storage in solution, although the activity of the immobilized enzyme was lower in comparison with the free enzyme. A stable immobilized system and long storage life are convenient for applications that would not be feasible with a soluble enzyme system. These results highlighted the technical and biochemical benefits of immobilized urease over the free enzyme.

Urease immobilized polymer hydrogel: Long-term stability and enhancement of enzymatic activity.

Science.gov (United States)

Kutcherlapati, S N Raju; Yeole, Niranjan; Jana, Tushar

2016-02-01

A method has been developed in which an enzyme namely urease was immobilized inside hydrogel matrix to study the stability and enzymatic activity in room temperature (∼27-30°C). This urease coupled hydrogel (UCG) was obtained by amine-acid coupling reaction and this procedure is such that it ensured the wider opening of mobile flap of enzyme active site. A systematic comparison of urea-urease assay and the detailed kinetic data clearly revealed that the urease shows activity for more than a month when stored at ∼27-30°C in case of UCG whereas it becomes inactive in case of free urease (enzyme in buffer solution). The aqueous microenvironment inside the hydrogel, unusual morphological features and thermal behaviour were believed to be the reasons for unexpected behaviour. UCG displayed enzyme activity at basic pH and up to 60°C. UCG showed significant enhancement in activity against thermal degradation compared to free urease. In summary, this method is a suitable process to stabilize the biomacromolecules in standard room temperature for many practical uses. Copyright © 2015 Elsevier Inc. All rights reserved.

Soybean roots retain the seed urease isozyme synthesized during embryo development

International Nuclear Information System (INIS)

Torisky, R.S.; Polacco, J.C.

1990-01-01

Roots of young soybean (Glycine max [L.] Merr.) plants (up to 25 days old) contain two distinct urease isozymes, which are separable by hydroxyapatite chromatography. These two urease species (URE1 and URE2) differ in: (a) electrophoretic mobility in native gels, (b) pH dependence, and (c) recognition by a monoclonal antibody specific for the seed (embryo-specific) urease. By these parameters root URE1 urease is similar to the abundant embryo-specific urease isozyme, while root URE2 resembles the ubiquitous urease which has previously been found in all soybean tissues examined (leaf, embryo, seed coat, and cultured cells). The embryo-specific and ubiquitous urease isozymes are products of the Eu1 and Eu4 structural genes, respectively. Roots of the eu1-sun/eu1-sun genotype, which lacks the embryo-specific urease (i.e. seed urease-null), contain no URE1 urease activity. Roots of eu4/eu4, which lacks ubiquitous urease, lack the URE2 (leaflike) urease activity. From these genetic and biochemical criteria, then, we conclude that URE1 and URE2 are the embryo-specific and ubiquitous ureases, respectively. Adventitious roots generated from cuttings of any urease genotype lack URE1 activity. In seedling roots the seedlike (URE1) activity declines during development. Roots of 3-week-old plants contain 5% of the total URE1 activity of the radicle of 4-day-old seedlings, which, in turn, has approximately the same urease activity level as the dormant embryonic axis. The embryo-specific urease incorporates label from [ 35 S]methionine during embryo development but not during germination, indicating that there is no de novo synthesis of the embryo-specific (URE1) urease in the germinating root

Caries-free subjects have high levels of urease and arginine deiminase activity

Directory of Open Access Journals (Sweden)

Evelyn REYES

2014-06-01

Full Text Available Objectives: This study investigated the relationship between urease and arginine deiminase system (ADS activities and dental caries through a cross-sectional study. Material and Methods: Urease and ADS activities were measured in saliva and plaque samples from 10 caries-free subjects and 13 caries-active. Urease activity was obtained from the ammonia produced by incubation of plaque and saliva samples in urea. ADS activity was obtained from the ammonia generated by the arginine-HCl and Tris-maleate buffer. Specific activity was defined as micromoles of ammonia per minute per milligram of protein. Shapiro-Wilk statistical test was used to analyze the distribution of the data, and Mann-Whitney test was used to determine the significance of the data. Results: The specific urease activity in saliva and plaque was significantly higher in individuals with low DMFT scores. ADS activity in saliva (6.050 vs 1.350, p=0.0154 and plaque (8.830 vs 1.210, p=0.025 was also higher in individuals with low DMFT scores. Conclusions: Caries-free subjects had a higher ammonia generation activity by urease and arginine deiminase system for both saliva and plaque samples than low caries-active subjects. High levels of alkali production in oral environment were related to caries-free subjects.

Structure of UreG/UreF/UreH Complex Reveals How Urease Accessory Proteins Facilitate Maturation of Helicobacter pylori Urease

Science.gov (United States)

Fong, Yu Hang; Wong, Ho Chun; Yuen, Man Hon; Lau, Pak Ho; Chen, Yu Wai; Wong, Kam-Bo

2013-01-01

Urease is a metalloenzyme essential for the survival of Helicobacter pylori in acidic gastric environment. Maturation of urease involves carbamylation of Lys219 and insertion of two nickel ions at its active site. This process requires GTP hydrolysis and the formation of a preactivation complex consisting of apo-urease and urease accessory proteins UreF, UreH, and UreG. UreF and UreH form a complex to recruit UreG, which is a SIMIBI class GTPase, to the preactivation complex. We report here the crystal structure of the UreG/UreF/UreH complex, which illustrates how UreF and UreH facilitate dimerization of UreG, and assembles its metal binding site by juxtaposing two invariant Cys66-Pro67-His68 metal binding motif at the interface to form the (UreG/UreF/UreH)2 complex. Interaction studies revealed that addition of nickel and GTP to the UreG/UreF/UreH complex releases a UreG dimer that binds a nickel ion at the dimeric interface. Substitution of Cys66 and His68 with alanine abolishes the formation of the nickel-charged UreG dimer. This nickel-charged UreG dimer can activate urease in vitro in the presence of the UreF/UreH complex. Static light scattering and atomic absorption spectroscopy measurements demonstrated that the nickel-charged UreG dimer, upon GTP hydrolysis, reverts to its monomeric form and releases nickel to urease. Based on our results, we propose a mechanism on how urease accessory proteins facilitate maturation of urease. PMID:24115911

Colorimetric detection of urea, urease, and urease inhibitor based on the peroxidase-like activity of gold nanoparticles.

Science.gov (United States)

Deng, Hao-Hua; Hong, Guo-Lin; Lin, Feng-Lin; Liu, Ai-Lin; Xia, Xing-Hua; Chen, Wei

2016-04-07

Herein, we reported for the first time that gold nanoparticles-catalyzed 3,3',5,5'-tetramethylbenzidine-H2O2 system can serve as an ultrasensitive colorimetric pH indicator. Gold nanoparticles acted as a catalyst and imitated the function of horseradish peroxidase. The absorbance at 450 nm of the yellow-color product in the catalytic reaction exhibited a linear fashion over the pH range of 6.40-6.60. On the basis of this property, we constructed a novel sensing platform for the determination of urea, urease, and urease inhibitor. The limit of detection for urea and urease was 5 μM and 1.8 U/L, respectively. The half-maximal inhibition value IC50 of acetohydroxamic acid was found to be 0.05 mM. Urea in human urine and urease in soil were detected with satisfied results. Copyright © 2016 Elsevier B.V. All rights reserved.

Comparative study on Pulsed Laser Deposition and Matrix Assisted Pulsed Laser Evaporation of urease thin films

International Nuclear Information System (INIS)

Smausz, Tomi; Megyeri, Gabor; Kekesi, Renata; Vass, Csaba; Gyoergy, Eniko; Sima, Felix; Mihailescu, Ion N.; Hopp, Bela

2009-01-01

Urease thin films were produced by Matrix Assisted Pulsed Laser Evaporation (MAPLE) and Pulsed Laser Deposition from two types of targets: frozen water solutions of urease with different concentrations (1-10% m/v) and pure urease pellets. The fluence of the ablating KrF excimer laser was varied between 300 and 2200 mJ/cm 2 . Fourier transform infrared spectra of the deposited films showed no difference as compared to the original urease. Morphologic studies proved that the films consist of a smooth 'base' layer with embedded micrometer-sized droplets. Absorption-coefficient measurements contradicted the traditional 'absorptive matrix' model for MAPLE deposition. The laser energy was absorbed by urease clusters leading to a local heating-up and evaporation of the frozen matrix from the uppermost layer accompanied by the release of dissolved urease molecules. Significant enzymatic activity of urease was preserved only during matrix assisted transfer.

In vitro inhibition of Helicobacter pylori urease with non and semi fermented Camellia sinensis

Directory of Open Access Journals (Sweden)

Shoae Hassani A

2009-01-01

Full Text Available Purpose: Helicobacter pylori is the etiological agent in duodenal and peptic ulcers. The growing problem of antibiotic resistance by the organism demands the search for novel compounds, especially from natural sources. This study was conducted to evaluate the effect of Camellia sinensis extracts on the urease enzyme that is a major colonization factor for H. pylori. Methods: Minimum inhibitory concentrations of nonfermented and semifermented C. sinensis methanol: water extracts were assessed by broth dilution method. Examination of the urease function was performed by Mc Laren method, and urease production was detected on 12% SDS polyacrylamide gel electrophoresis from whole cell and membrane bound proteins. Results: Both extracts had inhibitory effects against H. pylori and urease production. At a concentration of 2.5 mg/ml of nonfermented extract and 3.5 mg/ml of semifermented extract the production of Ure A and Ure B subunits of the urease enzyme were inhibited completely. A concentration of 4 mg/ml of nonfermented and 5.5 mg/ml of semifermented extract were bactericidal for H. pylori. Conclusions: C. sinensis extracts, especially the nonfermented, could reduce H. pylori population and inhibit urease production at lower concentrations. The superior effect of nonfermented extract is due to its rich polyphenolic compounds and catechin contents.

Urease inhibitory profile of extracts and chemical constituents of Pistacia atlantica ssp. cabulica Stocks.

Science.gov (United States)

Uddin, Ghias; Ismail; Rauf, Abdur; Raza, Muslim; Khan, Haroon; Nasruddin; Khan, Majid; Farooq, Umar; Khan, Ajmal; Arifullah

2016-06-01

The current study was designed to evaluate the urease inhibitory profile of extract and fractions of Pistacia atlantica ssp. cabulica Stocks followed by bioactivity-guided isolated compounds. The crude extract was found significantly active with urease inhibitor (95.40% at 0.2 mg/mL) with IC50 values of 32.0 ± 0.28 μg/mL. Upon fractionation, ethyl acetate fraction displayed 100% urease inhibition with IC50 values of 19.9 ± 0.51 μg/mL at 0.2 mg/mL. However, n-hexane and chloroform fractions exhibited insignificant urease inhibition. Similarly, the isolated compound, transilitin (1) and dihydro luteolin (2) demonstrated marked urease attenuation with 95 and 98% respectively, at 0.15 mg/mL. Both the isolated compounds showed marked potency with IC50 values of 8.54 ± 0.54 and 9.58 ± 2.22 μg/mL, respectively. In short, both the extract and fractions and isolated compounds showed marked urease inhibition and thus a useful natural source of urease inhibition.

Structural insight into the binding interactions of modeled structure of Arabidopsis thaliana urease with urea: an in silico study.

Science.gov (United States)

Yata, Vinod Kumar; Thapa, Arun; Mattaparthi, Venkata Satish Kumar

2015-01-01

Urease (EC 3.5.1.5., urea amidohydrolase) catalyzes the hydrolysis of urea to ammonia and carbon dioxide. Urease is present to a greater abundance in plants and plays significant role related to nitrogen recycling from urea. But little is known about the structure and function of the urease derived from the Arabidopsis thaliana, the model system of choice for research in plant biology. In this study, a three-dimensional structural model of A. thaliana urease was constructed using computer-aided molecular modeling technique. The characteristic structural features of the modeled structure were then studied using atomistic molecular dynamics simulation. It was observed that the modeled structure was stable and regions between residues index (50-80, 500-700) to be significantly flexible. From the docking studies, we detected the possible binding interactions of modeled urease with urea. Ala399, Ile675, Thr398, and Thr679 residues of A. thaliana urease were observed to be significantly involved in binding with the substrate urea. We also compared the docking studies of ureases from other sources such as Canavalia ensiformis, Helicobacter pylori, and Bacillus pasteurii. In addition, we carried out mutation analysis to find the highly mutable amino acid residues of modeled A. thaliana urease. In this particular study, we observed Met485, Tyr510, Ser786, Val426, and Lys765 to be highly mutable amino acids. These results are significant for the mutagenesis analysis. As a whole, this study expounds the salient structural features as well the binding interactions of the modeled structure of A. thaliana urease.

Effect of Azospirillum brasilense inoculation on urease activity in soil and gamma-sterilized soil

International Nuclear Information System (INIS)

Perotti, E.B.R.; Pidello, A.

1999-01-01

Azospirillum spp. is considered a PGPR (plant growth promoting rhyzobacteria) bacterium, besides this interest, there is little information about its effects on other functional microbial groups or on soil enzymes. In this paper, the impact that Azospirillum brasilense 7001 inoculation has on urease activity expression in a Typic Argiudoll was studied. Evolution of urease activity of soil and of gamma irradiation (25 KGy) sterilized soil, and the inoculated strain survival were tested. The relation between soil urease activity and soil NH 4 +-N was also determined. In γ-sterilized soil, urease activity of inoculated soil increased with time, showing significant differences with regard to the control soil without inoculum at day 15. In non-sterile soil, urease activity decreased during the studied period in all treatments; in inoculated soil, it showed higher or lower values than the control depending on sampling time. Azospirillum survival was important and different according to soil condition conditions. The negative relation between NH 4 +-N concentration and soil urease activity (r 2 = 0.62) was observed in inoculated soil. The role of the addition of autoclaved inoculum in the urease activity expression is discussed. The research proves that in both studied situations Azospirillum modified soil urease activity, and that the competition with native microorganisms and soil NH 4 +-N may affect this bacterium capacity. (author)

Mutational and Computational Evidence That a Nickel-Transfer Tunnel in UreD Is Used for Activation of Klebsiella aerogenes Urease.

Science.gov (United States)

Farrugia, Mark A; Wang, Beibei; Feig, Michael; Hausinger, Robert P

2015-10-20

Nickel-containing urease from Klebsiella aerogenes requires four accessory proteins for proper active site metalation. The metallochaperone UreE delivers nickel to UreG, a GTPase that forms a UreD/UreF/UreG complex, which binds to urease apoprotein via UreD. Prior in silico analysis of the homologous, structurally characterized UreH/UreF/UreG complex from Helicobacter pylori identified a water tunnel originating at a likely nickel-binding motif in UreG, passing through UreF, and exiting UreH, suggestive of a role for the channel in providing the metal to urease apoprotein for its activation; however, no experimental support was reported for the significance of this tunnel. Here, specific variants were designed to disrupt a comparable 34.6 Å predicted internal tunnel, alternative channels, and surface sites for UreD. Cells producing a set of tunnel-disrupting variants of UreD exhibited greatly reduced urease specific activities, whereas other mutants had no appreciable effect on activity. Affinity pull-down studies of cell-free extracts from tunnel-disrupting mutant cultures showed no loss of UreD interactions with urease or UreF/UreG. The nickel contents of urease samples enriched from activity-deficient cultures were decreased, while zinc and iron incorporation increased. Molecular dynamics simulations revealed size restrictions in the internal channels of the UreD variants. These findings support the role of a molecular tunnel in UreD as a direct facilitator of nickel transfer into urease, illustrating a new paradigm in active site metallocenter assembly.

Effect of ohmic heating of soymilk on urease inactivation and kinetic analysis in holding time.

Science.gov (United States)

Li, Fa-De; Chen, Chen; Ren, Jie; Wang, Ranran; Wu, Peng

2015-02-01

To verify the effect of the ohmic heating on the urease activity in the soymilk, the ohmic heating methods with the different electrical field conditions (the frequency and the voltage ranging from 50 to 10 kHz and from 160 to 220 V, respectively) were employed. The results showed that if the value of the urease activity measured with the quantitative spectrophotometry method was lower than 16.8 IU, the urease activity measured with the qualitative method was negative. The urease activity of the sample ohmically heated was significantly lower than that of the sample conventionally heated (P urease inactivation. In addition, the inactivation kinetics of the urease in the soymilk could be described with a biphasic model during holding time at a target temperature. Thus, it was concluded that the urease in the soymilk would contain 2 isoenzymes, one is the thermolabile fraction, the other the thermostable fraction, and that the thermostable isoenzyme could not be completely inactivated when the holding time increased, whether the soymilk was cooked with the conventional method or with the ohmic heating method. Therefore, the electric field had no effect on the inactivation of the thermostable isoenzyme of the urease. © 2015 Institute of Food Technologists®

Plant growth regulators induced urease activity in Cucurbita pepo L. cotyledons.

Science.gov (United States)

El Shora, Hamed M; Ali, Awatif S

2016-03-01

This study is aimed to investigate the activity of urease (EC 3.5.1.5, urea amidohydrolase) that catalyzes the hydrolysis of urea in 5-day-old Cucurbita pepo cotyledons subjected to various concentrations of different growth regulators. The treatment of C. pepo cotyledons with different concentrations (100-600 μmol) of different auxins [indole-3-acetic acid (IAA), indole butyric acid (IBA), indole propionic acid (IPA) and naphthalene acetic acid (NAA)]; or with different concentrations (100-300 μmol) of different cytokinins [kinetin, zeatin and benzyladenine (6-BA)] resulted in a significant increase of urease activity, compared to control. The optimal effects were recorded for each of 500 μmol of IAA and 300 μmol of zeatin treatments. A gradual increase in urease activity was detected in cotyledons treated with various concentrations (0.2-1.0 mM) of 28-homobrassinolide (HBL), in relative to control. A substantial increase in urease activity was observed in cotyledons subjected to different concentrations of triazole (10-60 mg L(-1)), containing either triadimefon (TDM) or hexaconazole (HEX), compared to control. The combination of 300 μmol zeatin with any of protein inhibitors, namely 5-fluorouridine (FUrd), cordycepin and α-amanitin, resulted in the alleviation of their inhibitory effect on the urease activity.

Klebsiella aerogenes UreF: Identification of the UreG Binding Site and Role in Enhancing the Fidelity of Urease Activation†

Science.gov (United States)

Boer, Jodi L.; Hausinger, Robert P.

2012-01-01

The Ni-containing active site of Klebsiella aerogenes urease is assembled through the concerted action of the UreD, UreE, UreF, and UreG accessory proteins. UreE functions as a metallochaperone that delivers Ni to a complex of UreD—UreF—UreG bound to urease apoprotein, with UreG serving as a GTPase during enzyme activation. The present study focuses on the role of UreF, previously proposed to act as a GTPase activating protein (GAP) of UreG. Sixteen conserved UreF surface residues that may play roles in protein:protein interactions were independently changed to Ala. When produced in the context of the entire urease gene cluster, cell-free extracts of nine site-directed mutants had less than 10% of the wild-type urease activity. Enrichment of the variant forms of UreF, as the UreE-F fusion proteins, uniformly resulted in co-purification of UreD and urease apoprotein; whereas UreG bound to only a subset of the species. Notably, reduced interaction with UreG correlated with the low activity mutants. The affected residues in UreF map to a distinct surface on the crystal structure, defining the UreG binding site. In contrast to the hypothesis that UreF is a GAP, the UreD—UreF—UreG—urease apoprotein complex containing K165A UreF exhibited significantly greater levels of GTPase activity than that containing the wild-type protein. Additional studies demonstrated the UreG GTPase activity was largely uncoupled from urease activation for the complex containing this UreF variant. Further experiments with these complexes provided evidence that UreF gates the GTPase activity of UreG to enhance the fidelity of urease metallocenter assembly, especially in the presence of the non-cognate metal Zn. PMID:22369361

Bacterial Urease and its Role in Long-Lasting Human Diseases

Science.gov (United States)

Konieczna, Iwona; Żarnowiec, Paulina; Kwinkowski, Marek; Kolesińska, Beata; Frączyk, Justyna; Kamiński, Zbigniew; Kaca, Wiesław

2012-01-01

Urease is a virulence factor found in various pathogenic bacteria. It is essential in colonization of a host organism and in maintenance of bacterial cells in tissues. Due to its enzymatic activity, urease has a toxic effect on human cells. The presence of ureolytic activity is an important marker of a number of bacterial infections. Urease is also an immunogenic protein and is recognized by antibodies present in human sera. The presence of such antibodies is connected with progress of several long-lasting diseases, like rheumatoid arthritis, atherosclerosis or urinary tract infections. In bacterial ureases, motives with a sequence and/or structure similar to human proteins may occur. This phenomenon, known as molecular mimicry, leads to the appearance of autoantibodies, which take part in host molecules destruction. Detection of antibodies-binding motives (epitopes) in bacterial proteins is a complex process. However, organic chemistry tools, such as synthetic peptide libraries, are helpful in both, epitope mapping as well as in serologic investigations. In this review, we present a synthetic report on a molecular organization of bacterial ureases - genetic as well as structural. We characterize methods used in detecting urease and ureolytic activity, including techniques applied in disease diagnostic processes and in chemical synthesis of urease epitopes. The review also provides a summary of knowledge about a toxic effect of bacterial ureases on human body and about occurrence of anti-urease antibodies in long-lasting diseases. PMID:23305365

[Effect of elevated atmospheric CO2 on soil urease and phosphatase activities].

Science.gov (United States)

Chen, Lijun; Wu, Zhijie; Huang, Guohong; Zhou, Likai

2002-10-01

The response of soil urease and phosphatase activities at different rice growth stages to free air CO2 enrichment (FACE) was studied. The results showed that comparing with the ambient atmospheric CO2 concentration (370 mumol.mol-1), FACE (570 mumol.mol-1) significantly increased the urease activity of 0-5 cm soil layer at the vigorous growth stage of rice, whole that of 5-10 cm layer had no significant change during the whole growing season. Phosphatase activity of 0-5 cm and 5-10 cm soil layers significantly increased, and the peak increment was at the vigorous growth stage of rice.

Protein Tunnels: The Case of Urease Accessory Proteins.

Science.gov (United States)

Musiani, Francesco; Gioia, Dario; Masetti, Matteo; Falchi, Federico; Cavalli, Andrea; Recanatini, Maurizio; Ciurli, Stefano

2017-05-09

Transition metals are both essential micronutrients and limited in environmental availability. The Ni(II)-dependent urease protein, the most efficient enzyme known to date, is a paradigm for studying the strategies that cells use to handle an essential, yet toxic, metal ion. Urease is a virulence factor of several human pathogens, in addition to decreasing the efficiency of soil organic nitrogen fertilization. Ni(II) insertion in the urease active site is performed through the action of three essential accessory proteins: UreD, UreF, and UreG. The crystal structure of the UreD-UreF-UreG complex from the human pathogen Helicobacter pylori (HpUreDFG) revealed the presence of tunnels that cross the entire length of both UreF and UreD, potentially able to deliver Ni(II) ions from UreG to apo-urease. Atomistic molecular dynamics simulations performed on the HpUreDFG complex in explicit solvent and at physiological ionic conditions demonstrate the stability of these protein tunnels in solution and provide insights on the trafficking of water molecules inside the tunnels. The presence of different alternative routes across the identified tunnels for Ni(II) ions, water molecules, and carbonate ions, all involved in urease activation, is highlighted here, and their potential role in the urease activation mechanism is discussed.

Comparison of Helicobacter pylori Urease Inhibition by Rhizoma Coptidis, Cortex Phellodendri and Berberine: Mechanisms of Interaction with the Sulfhydryl Group.

Science.gov (United States)

Li, Cailan; Xie, Jianhui; Chen, Xiaoying; Mo, Zhizhun; Wu, Wen; Liang, Yeer; Su, Zuqing; Li, Qian; Li, Yucui; Su, Ziren; Yang, Xiaobo

2016-03-01

Rhizoma Coptidis, Cortex Phellodendri, and berberine were reported to inhibit Helicobacter pylori. However, the underlying mechanism remained elusive. Urease plays a vital role in H. pylori colonization and virulence. In this work, aqueous extracts of Rhizoma Coptidis, Cortex Phellodendri of different origins, and purified berberine were investigated against H. pylori urease and jack bean urease to elucidate the inhibitory capacity, kinetics, and mechanism. Results showed that berberine was the major chemical component in Rhizoma Coptidis and Cortex Phellodendri, and the content of berberine in Rhizoma Coptidis was higher than in Cortex Phellodendri. The IC50 values of Rhizoma Coptidis were significantly lower than those Cortex Phellodendri and purified berberine, of which Coptis chinensis was shown to be the most active concentration- and time-dependent urease inhibitor. The Lineweaver-Burk plot analysis indicated that the inhibition pattern of C. chinensis against urease was noncompetitive for both H. pylori urease and jack bean urease. Thiol protectors (L-cysteine, glutathione, and dithiothreithol) significantly protected urease from the loss of enzymatic activity, while fluoride and boric acid showed weaker protection, indicating the active-site sulfhydryl group was possibly responsible for its inhibition. Furthermore, the urease inhibition proved to be reversible since C. chinensis-blocked urease could be reactivated by glutathione. The results suggested that the anti-urease activity of Rhizoma Coptidis was superior to that of Cortex Phellodendri and berberine, which was believed to be more likely to correlate to the content of total alkaloids rather than berberine monomer. The concentration- and time-dependent, reversible, and noncompetitive inhibition against urease by C. chinensis might be attributed to its interaction with the sulfhydryl group of the active site of urease. Georg Thieme Verlag KG Stuttgart · New York.

Inactivation of urease by catechol: Kinetics and structure.

Science.gov (United States)

Mazzei, Luca; Cianci, Michele; Musiani, Francesco; Lente, Gábor; Palombo, Marta; Ciurli, Stefano

2017-01-01

Urease is a Ni(II)-containing enzyme that catalyzes the hydrolysis of urea to yield ammonia and carbamate at a rate 10 15 times higher than the uncatalyzed reaction. Urease is a virulence factor of several human pathogens, in addition to decreasing the efficiency of soil organic nitrogen fertilization. Therefore, efficient urease inhibitors are actively sought. In this study, we describe a molecular characterization of the interaction between urease from Sporosarcina pasteurii (SPU) and Canavalia ensiformis (jack bean, JBU) with catechol, a model polyphenol. In particular, catechol irreversibly inactivates both SPU and JBU with a complex radical-based autocatalytic multistep mechanism. The crystal structure of the SPU-catechol complex, determined at 1.50Å resolution, reveals the structural details of the enzyme inhibition. Copyright © 2016 Elsevier Inc. All rights reserved.

Robust Synthesis of Ciprofloxacin-Capped Metallic Nanoparticles and Their Urease Inhibitory Assay.

Science.gov (United States)

Nisar, Muhammad; Khan, Shujaat Ali; Qayum, Mughal; Khan, Ajmal; Farooq, Umar; Jaafar, Hawa Z E; Zia-Ul-Haq, Muhammad; Ali, Rashid

2016-03-25

The fluoroquinolone antibacterial drug ciprofloxacin (cip) has been used to cap metallic (silver and gold) nanoparticles by a robust one pot synthetic method under optimized conditions, using NaBH₄ as a mild reducing agent. Metallic nanoparticles (MNPs) showed constancy against variations in pH, table salt (NaCl) solution, and heat. Capping with metal ions (Ag/Au-cip) has significant implications for the solubility, pharmacokinetics and bioavailability of fluoroquinolone molecules. The metallic nanoparticles were characterized by several techniques such as ultraviolet visible spectroscopy (UV), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) methods. The nanoparticles synthesized using silver and gold were subjected to energy dispersive X-ray tests in order to show their metallic composition. The NH moiety of the piperazine group capped the Ag/Au surfaces, as revealed by spectroscopic studies. The synthesized nanoparticles were also assessed for urease inhibition potential. Fascinatingly, both Ag-cip and Au-cip NPs exhibited significant urease enzyme inhibitory potential, with IC50 = 1.181 ± 0.02 µg/mL and 52.55 ± 2.3 µg/mL, compared to ciprofloxacin (IC50 = 82.95 ± 1.62 µg/mL). MNPs also exhibited significant antibacterial activity against selected bacterial strains.

Isolation and molecular characterization of a urease-negative Actinobacillus pleuropneumoniae mutant.

Science.gov (United States)

Ito, Hiroya; Takahashi, Sayaka; Asai, Tetsuo; Tamura, Yutaka; Yamamoto, Koshi

2018-01-01

An atypical urease-negative mutant of Actinobacillus pleuropneumoniae serovar 2 was isolated in Japan. Nucleotide sequence analysis of the urease gene cluster revealed that the insertion of a short DNA sequence into the cbiM gene was responsible for the urease-negative activity of the mutant. Veterinary diagnostic laboratories should be watchful for the presence of aberrant urease-negative A. pleuropneumoniae isolates.

Infection (urease) stones.

Science.gov (United States)

Griffith, D P; Osborne, C A

1987-01-01

Infection-induced stones in man probably form solely as a consequence of urealysis which is catalyzed by the bacterial protein urease. Urease stones composed of struvite and carbonate-apatite may form primarily, or as secondary stones or pre-existent metabolic stones. Struvite stones form and grow rapidly owing to (a) supersaturation of urine with stone forming salts, (b) 'salting out' of poorly soluble organic substances normally dissolved in urine and (c) ammonia-induced destruction of the normally protective urothelial glycosaminoglycan layer. Immature (predominantly organic) matrix stones mature into densely mineralized stones. Curative treatment is possible only by eliminating all of the stone and by eradicating all urinary and parenchymal infection. A variety of operative and pharmaceutical approaches are available. Patient treatment must be individualized inasmuch as some patients are better candidates for one type of treatment than another.

Supramolecular polyaniline hydrogel as a support for urease

International Nuclear Information System (INIS)

Słoniewska, Anna; Pałys, Barbara

2014-01-01

Supramolecular hydrogels of conducting polymers are successfully used in bioelectrochemistry because of their mechanical and swelling properties of gels added to the specific electron transport properties of conducting polymers. We have studied polyaniline-poly(styrene sulfonate) (PANI–PSS) hydrogel as a substrate for the urease. The hydrogels were synthesized at pH = 0 and pH = 5. PANI–PSS hydrogel is a supramolecular self-assembly material consisting of positively-charged PANI chains and negatively-charged PSS chains. The hydrogel was studied by cyclic voltammetry, infrared and Raman spectroscopy and Scanning Electron Microscopy (SEM). Raman spectra revealed presence of phenazine rings in the hydrogel structure. Phenazine rings form covalent cross-linkers contributing to the hydrogel mechanical stability. The covalent cross-linkers influence the cyclic voltammetry responses of the hydrogel in acidic media. We tested the activity of urease immobilized in the PANI–PSS hydrogel by the physical adsorption or by the covalent bonding with the carbodiimide reaction. The enzyme immobilized in hydrogels prepared at higher pH value reveals significantly higher sensitivity. The method of the enzyme immobilization has smaller impact on the sensitivity. All hydrogel sensors reveal largely higher sensitivity to urea comparing to urease immobilized in the typical electrochemically deposited PANI films. The sensitivity of urease covalently bond to the hydrogel obtained at pH = 5 was as high as 1693 μA/(mol dm 3 ). The sensor response was linear in the urea concentration range from 10 −4 to 7 × 10 −2 mol/dm 3

A single gene (Eu4) encodes the tissue-ubiquitous urease of soybean.

Science.gov (United States)

Torisky, R S; Griffin, J D; Yenofsky, R L; Polacco, J C

1994-02-01

We sought to determine the genetic basis of expression of the ubiquitous (metabolic) urease of soybean. This isozyme is termed the metabolic urease because its loss, in eu4/eu4 mutants, leads to accumulation of urea, whereas loss of the embryo-specific urease isozyme does not. The eu4 lesion eliminated the expression of the ubiquitous urease in vegetative and embryonic tissues. RFLP analysis placed urease clone LC4 near, or within, the Eu4 locus. Sequence comparison of urease proteins (ubiquitous and embryo-specific) and clones (LC4 and LS1) indicated that LC4 and LS1 encode ubiquitous and embryo-specific ureases, respectively. That LC4 is transcribed into poly(A)+ RNA in all tissues was indicated by the amplification of its transcript by an LC4-specific PCR primer. (The LS1-specific primer, on the other hand, amplified poly(A)+ RNA only from developing embryos expressing the embryo-specific urease.) These observations are consistent with Eu4 being the ubiquitous urease structural gene contained in the LC4 clone. In agreement with this notion, the mutant phenotype of eu4/eu4 callus was partially corrected by the LC4 urease gene introduced by particle bombardment.

21 CFR 184.1924 - Urease enzyme preparation from Lactobacillus fermentum.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Urease enzyme preparation from Lactobacillus... GENERALLY RECOGNIZED AS SAFE Listing of Specific Substances Affirmed as GRAS § 184.1924 Urease enzyme..., nontoxicogenic bacterium Lactobacillus fermentum. It contains the enzyme urease (CAS Reg. No. 9002-13-5), which...

Urease Activity Represents an Alternative Pathway for Mycobacterium tuberculosis Nitrogen Metabolism

Science.gov (United States)

Lin, Wenwei; Mathys, Vanessa; Ang, Emily Lei Yin; Koh, Vanessa Hui Qi; Martínez Gómez, Julia María; Ang, Michelle Lay Teng; Zainul Rahim, Siti Zarina; Tan, Mai Ping; Pethe, Kevin

2012-01-01

Urease represents a critical virulence factor for some bacterial species through its alkalizing effect, which helps neutralize the acidic microenvironment of the pathogen. In addition, urease serves as a nitrogen source provider for bacterial growth. Pathogenic mycobacteria express a functional urease, but its role during infection has yet to be characterized. In this study, we constructed a urease-deficient Mycobacterium tuberculosis strain and confirmed the alkalizing effect of the urease activity within the mycobacterium-containing vacuole in resting macrophages but not in the more acidic phagolysosomal compartment of activated macrophages. However, the urease-mediated alkalizing effect did not confer any growth advantage on M. tuberculosis in macrophages, as evidenced by comparable growth profiles for the mutant, wild-type (WT), and complemented strains. In contrast, the urease-deficient mutant exhibited impaired in vitro growth compared to the WT and complemented strains when urea was the sole source of nitrogen. Substantial amounts of ammonia were produced by the WT and complemented strains, but not with the urease-deficient mutant, which represents the actual nitrogen source for mycobacterial growth. However, the urease-deficient mutant displayed parental colonization profiles in the lungs, spleen, and liver in mice. Together, our data demonstrate a role for the urease activity in M. tuberculosis nitrogen metabolism that could be crucial for the pathogen's survival in nutrient-limited microenvironments where urea is the sole nitrogen source. Our work supports the notion that M. tuberculosis virulence correlates with its unique metabolic versatility and ability to utilize virtually any carbon and nitrogen sources available in its environment. PMID:22645285

Urease testing of mycobacteria with BACTEC radiometric instrumentation

International Nuclear Information System (INIS)

Damato, J.J.; Collins, M.T.; McClatchy, J.K.

1982-01-01

A total of 140 mycobacterial isolates from patients treated at Fitzsimons Army Medical Center or the National Jewish Hospital and Research Center and from animal specimens submitted to the National Veterinary Services Laboratory were tested by using a urease procedure modified for use with a BACTEC model 301. Mycobacterial suspensions were prepared by using Middlebrook 7H10 Tween broth. Of the 98 mycobacteria isolates which were urease positive utilizing standard methodology, all were positive using the radiometric procedures. Similarly, all 42 urease-negative isolates were also negative employing the new methodology. Although maximum radiometric readings were observed at 48 h, all positive strains were readily identified 24 h after inoculation without sacrificing either test sensitivity or specificity. Thus, urease testing of mycobacteria, using the modified BACTEC radiometric methodology, was as sensitive, as specific, and more rapid than conventional methods

Food constituents enhance urease activity in Healicobacter pylori.

OpenAIRE

Mizote, Tomoko; Inatsu, Sakiko; Ehara, Keiko

2005-01-01

Urease activity of Helicobacter pylori recovered from the stomach of H. pylori-infected Mongolian gerbils was affected by the diet used after infection. The effect of dietary components on urease activity was investigated by growth of H. pylori in…

Genetic analysis of an Escherichia coli urease locus: evidence of DNA rearrangement.

OpenAIRE

Collins, C M; Falkow, S

1988-01-01

Ureolytic Escherichia coli strains are uncommon clinical isolates. The urease phenotype in a large percentage of these isolates is unstable and lost upon storage. We examined two urease-positive uropathogenic E. coli isolates that give off urease-negative segregants and determined that the urease phenotype was chromosomally encoded. The urease phenotype was cloned from E. coli 1021 and found to be encoded on a 9.4-kilobase HindIII restriction fragment. Transposon mutagenesis indicated that at...

Inhibition of Helicobacter pylori and Its Associated Urease by Palmatine: Investigation on the Potential Mechanism.

Science.gov (United States)

Zhou, Jiang-Tao; Li, Cai-Lan; Tan, Li-Hua; Xu, Yi-Fei; Liu, Yu-Hong; Mo, Zhi-Zhun; Dou, Yao-Xing; Su, Rui; Su, Zi-Ren; Huang, Ping; Xie, Jian-Hui

2017-01-01

In this paper, we evaluated the anti-Helicobacter pylori activity and the possible inhibitory effect on its associated urease by Palmatine (Pal) from Coptis chinensis, and explored the potential underlying mechanism. Results indicated that Pal exerted inhibitory effect on four tested H. pylori strains (ATCC 43504, NCTC 26695, SS1 and ICDC 111001) by the agar dilution test with minimum inhibitory concentration (MIC) values ranging from 100 to 200 μg/mL under neutral environment (pH 7.4), and from 75 to 100 μg/mL under acidic conditions (pH 5.3), respectively. Pal was observed to significantly inhibit both H. pylori urease (HPU) and jack bean urease (JBU) in a dose-dependent manner, with IC50 values of 0.53 ± 0.01 mM and 0.03 ± 0.00 mM, respectively, as compared with acetohydroxamic acid, a well-known urease inhibitor (0.07 ± 0.01 mM for HPU and 0.02 ± 0.00 mM for JBU, respectively). Kinetic analyses showed that the type of urease inhibition by Pal was noncompetitive for both HPU and JBU. Higher effectiveness of thiol protectors against urease inhibition than the competitive Ni2+ binding inhibitors was observed, indicating the essential role of the active-site sulfhydryl group in the urease inhibition by Pal. DTT reactivation assay indicated that the inhibition on the two ureases was reversible, further supporting that sulfhydryl group should be obligatory for urease inhibition by Pal. Furthermore, molecular docking study indicated that Pal interacted with the important sulfhydryl groups and inhibited the active enzymatic conformation through N-H ∙ π interaction, but did not interact with the active site Ni2+. Taken together, Pal was an effective inhibitor of H. pylori and its urease targeting the sulfhydryl groups, representing a promising candidate as novel urease inhibitor. This investigation also gave additional scientific support to the use of C. chinensis to treat H. pylori-related gastrointestinal diseases in traditional Chinese medicine. Pal might be

Determination of Urease Biochemical Properties of Asparagus Bean (Vigna unguiculata ssp sesquipedalis L.)

Science.gov (United States)

Zusfahair; Ningsih, D. R.; Fatoni, A.; Pertiwi, D. S.

2018-04-01

Urease is enzyme that plays a role in nitrogen metabolism during plant germination. Plants that produce a lot of urease are grains. This study used asparagus bean as source of urease. The purpose of this research is to learn the effect of germination time on the activity of urease enzyme from asparagus bean and its biochemical properties. The research was started by germination of asparagus bean on day 2, 4, 6, 8, 10 and 12. Asparagus bean sprouts were extracted using acetone and separated by centrifugation to obtain the crude extract of urease. The biochemical properties of the crude extract of urease was further determined including: the effect of temperature, pH, substrate concentration, and metal addition to urease activity. The urease activity is determined by the Nessler method. The germination time of asparagus bean in yielding urease enzyme reached the optimum activity on the 8th day with activity value of 593.7 U/mL. The biochemical properties of urease from asparagus bean have optimum activity at 35 °C, pH 7.0 and substrate concentration 0.125% with activity value of 600 U/mL. Addition of CaCl2, SnCl2 and ZnCl2 metals decrease the activity of urease.

Structure of Rv1848 (UreA), the Mycobacterium tuberculosis urease γ subunit

International Nuclear Information System (INIS)

Habel, Jeff E.; Bursey, Evan H.; Rho, Beom-Seop; Kim, Chang-Yub; Segelke, Brent W.; Rupp, Bernhard; Park, Min S.; Terwilliger, Thomas C.; Hung, Li-Wei

2010-01-01

Crystal and solution structures of Rv1848 protein and their implications in the biological assembly of Mtb urease is presented. The crystal structure of the urease γ subunit (UreA) from Mycobacterium tuberculosis, Rv1848, has been determined at 1.8 Å resolution. The asymmetric unit contains three copies of Rv1848 arranged into a homotrimer that is similar to the UreA trimer in the structure of urease from Klebsiella aerogenes. Small-angle X-ray scattering experiments indicate that the Rv1848 protein also forms trimers in solution. The observed homotrimer and the organization of urease genes within the M. tuberculosis genome suggest that M. tuberculosis urease has the (αβγ) 3 composition observed for other bacterial ureases. The γ subunit may be of primary importance for the formation of the urease quaternary structure

Molecular docking of Glycine max and Medicago truncatula ureases with urea; bioinformatics approaches.

Science.gov (United States)

Filiz, Ertugrul; Vatansever, Recep; Ozyigit, Ibrahim Ilker

2016-03-01

Urease (EC 3.5.1.5) is a nickel-dependent metalloenzyme catalyzing the hydrolysis of urea into ammonia and carbon dioxide. It is present in many bacteria, fungi, yeasts and plants. Most species, with few exceptions, use nickel metalloenzyme urease to hydrolyze urea, which is one of the commonly used nitrogen fertilizer in plant growth thus its enzymatic hydrolysis possesses vital importance in agricultural practices. Considering the essentiality and importance of urea and urease activity in most plants, this study aimed to comparatively investigate the ureases of two important legume species such as Glycine max (soybean) and Medicago truncatula (barrel medic) from Fabaceae family. With additional plant species, primary and secondary structures of 37 plant ureases were comparatively analyzed using various bioinformatics tools. A structure based phylogeny was constructed using predicted 3D models of G. max and M. truncatula, whose crystallographic structures are not available, along with three additional solved urease structures from Canavalia ensiformis (PDB: 4GY7), Bacillus pasteurii (PDB: 4UBP) and Klebsiella aerogenes (PDB: 1FWJ). In addition, urease structures of these species were docked with urea to analyze the binding affinities, interacting amino acids and atom distances in urease-urea complexes. Furthermore, mutable amino acids which could potentially affect the protein active site, stability and flexibility as well as overall protein stability were analyzed in urease structures of G. max and M. truncatula. Plant ureases demonstrated similar physico-chemical properties with 833-878 amino acid residues and 89.39-90.91 kDa molecular weight with mainly acidic (5.15-6.10 pI) nature. Four protein domain structures such as urease gamma, urease beta, urease alpha and amidohydro 1 characterized the plant ureases. Secondary structure of plant ureases also demonstrated conserved protein architecture, with predominantly α-helix and random coil structures. In

Preparation and Properties of Urease Immobilized onto Glutaraldehyde Cross-linked Chitosan Beads

Institute of Scientific and Technical Information of China (English)

Zu Pei LIANG; Ya Qing FENG; Shu Xian MENG; Zhi Yan LIANG

2005-01-01

Urease was immobilized onto the glutaraldehyde cross-linked chitosan beads that were prepared under microwave irradiation. The activity and the yield of activity of immobilized urease was 10.83 U/g B and 47.7%, respectively. The conditions of urease immobilization were optimized. The properties of the immobilized urease were investigated and compared with that of the free enzyme.

Extraction, purification, kinetic and thermodynamic properties of urease from germinating Pisum Sativum L. seeds

Science.gov (United States)

2014-01-01

Background Urease, one of the highly efficient known enzymes, catalyzes the hydrolysis of urea into ammonia and carbon dioxide. The present study aimed to extract urease from pea seeds (Pisum Sativum L). The enzyme was then purified in three consequence steps: acetone precipitation, DEAE-cellulose ion-exchange chromatography, and gel filtration chromatography (Sephacryl S-200 column). Results The purification fold was 12.85 with a yield of 40%. The molecular weight of the isolated urease was estimated by chromatography to be 269,000 Daltons. Maximum urease activity (190 U/g) was achieved at the optimum conditions of 40°C and pH of 7.5 after 5 min of incubation. The kinetic parameters, K m and V max , were estimated by Lineweaver-Burk fits and found to be 500 mM and 333.3 U/g, respectively. The thermodynamic constants of activation, ΔH, E a , and ΔS, were determined using Arrhenius plot and found to be 21.20 kJ/mol, 23.7 kJ/mol, and 1.18 kJ/mol/K, respectively. Conclusions Urease was purified from germinating Pisum Sativum L. seeds. The purification fold, yield, and molecular weight were determined. The effects of pH, concentration of enzyme, temperature, concentration of substrate, and storage period on urease activity were examined. This may provide an insight on the various aspects of the property of the enzyme. The significance of extracting urease from different sources could play a good role in understanding the metabolism of urea in plants. PMID:25065975

Localization of urease activity in ureaplasma urealyticum cells

International Nuclear Information System (INIS)

Vinther, O.

1976-01-01

Measurements of the urease activity of various cell fractions of U. urealyticum showed that this activity was confined to the soluble fraction of the cytoplasm. An attempt was made to devise a method for electron microscopic detection of the sites of urease activity based on precipitation of electron-dense MnO 2 at the alkaline pH created by the hydrolysis of urea. The results obtained supported the previous results indicating a cytoplasmatic localization of the urease activity in the cells. Helical ribosome patterns were observed when glutaraldehyde-fixed cells were treated with cytochemical test solutions. (author)

Localization of urease activity in Ureaplasma urealyticum cells

Energy Technology Data Exchange (ETDEWEB)

Vinther, O [Aarhus Univ. (Denmark)

1976-01-01

Measurements of the urease activity of various cell fractions of U. urealyticum showed that this activity was confined to the soluble fraction of the cytoplasm. An attempt was made to devise a method for electron microscopic detection of the sites of urease activity based on precipitation of electron-dense MnO/sub 2/ at the alkaline pH created by the hydrolysis of urea. The results obtained supported the previous results indicating a cytoplasmatic localization of the urease activity in the cells. Helical ribosome patterns were observed when glutaraldehyde-fixed cells were treated with cytochemical test solutions.

Inhibition of urease by extracts derived from 15 Chinese medicinal herbs.

Science.gov (United States)

Shi, Da-Hua; Liu, Yu-Wei; Liu, Wei-Wei; Gu, Zhi-Feng

2011-07-01

Helicobacter pylori is a major causative factor in gastritis-like disorders, and urease plays a key role in Helicobacter pylori colonizing and persisting in the mucous layer of the human stomach. In China, a variety of Chinese medicinal herbs have been prescribed to attenuate or eradicate gastritis-like disorders. However, little is known about the urease inhibition of Chinese medicinal herbs. The present study was conducted to investigate the urease inhibition activities of the ethanol and water extracts of 15 Chinese medicinal herbs. The ethanol and water extracts derived from 15 medicinal herbs, traditionally used for the treatment of gastritis-like disorders in China, were tested for urease-inhibition activity using the phenol red method. Screened at 10 µg/mL, 14 ethanol extracts and 10 water extracts showed urease inhibition. The ethanol extracts of Magnolia officinalis Rehd. et Wils. (Magnoliaceae) and Cassia obtusifolia L. (Leguminosae) possessed inhibition rates higher than 50% with IC₅₀ values of 6.5 and 12.3 µg/mL, respectively. After fractionating successively, the petroleum ether fraction of the ethanol extracts of Magnolia officinalis showed the best activity with 90.8% urease inhibition at a concentration of 10 µg/mL. The bioautography of the petroleum ether fraction indicated the existence of the urease inhibitors in the herb. The present results indicated that some Chinese medicinal herbs might treat gastritis-like disorders via the inhibition of Helicobacter pylori urease and the further possibility for discovering useful novel urease inhibitors from the Chinese medicinal herbs.

Effects of plant urease inhibitor on crop nutrition and soil characters

International Nuclear Information System (INIS)

Wang Zhengyin; Xu Weihong; Huang Yun; Yuan Lujiang; Jia Zhongyuan; Zhou Jun; Ding Shuying

2002-01-01

A pot experiment was conducted to investigate the effects of 15 N-urea and 4 kinds of plant materials (P 1 , P 2 , P 3 and P 4 ) as urease inhibitor on sorghum and rice nutrition and soil characters. The results indicated that the growth, above-ground parts and roots weight of rice and sorghum were respectively promoted by 4 plant urease inhibitors and P 1 with little change of chl.a/chl.b ratios in these treatments. The content of amino acid in rice leaf and utilization rate of nitrogen by rice were enhanced by 12.9%-25.1% and 5.2%-7.7% respectively, and the utilization rate of nitrogen by sorghum was improved by urease inhibitor treatments (except P 1 ). Plant urease inhibitor could obviously increase the apparent utilization rate of nitrogen by 4.3%-19.2% for two crops and improve phosphorus and potassium uptake by rice plant but decrease phosphorus and potassium uptake by sorghum plant. The contents of soil alkali-hydrolyzable nitrogen were increased by plant urease inhibitor under two cultivated condition. The inhibition time of plant urease inhibitor to soil urease was short and it disappeared as 36 days of rice growth under flooded condition, while the activities of soil urease were decreased by 10.6%-18.3% at 48 days of sorghum growth in upland soil

Synthesis and Characterisation of Biocompatible Polymer-Conjugated Magnetic Beads for Enhancement Stability of Urease.

Science.gov (United States)

Doğaç, Yasemin Ispirli; Teke, Mustafa

2016-04-01

We reported natural polymer-conjugated magnetic featured urease systems for removal of urea effectively. The optimum temperature (20-60 °C), optimum pH (3.0-10.0), kinetic parameters, thermal stability (4-70 °C), pH stability (4.0-9.0), operational stability (0-250 min), reusability (18 times) and storage stability (24 weeks) were studied for characterisation of the urease-encapsulated biocompatible polymer-conjugated magnetic beads. Also, the surface groups and chemical structure of the magnetic beads were determined by using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). The all urease-encapsulated magnetic beads protected their stability of 30-45 % relative activity at 70 °C. A significant increase was observed at their pH stability compared with the free urease for both acidic and alkaline medium. Besides this, their repeatability activity were approximately 100 % during 4(th) run. They showed residual activity of 50 % after 16 weeks. The importance of this work is enhancement stability of immobilised urease by biocompatible polymer-conjugated magnetic beads for the industrial application based on removal of urea.

Factors Required for Activation of Urease as a Virulence Determinant in Cryptococcus neoformans

Science.gov (United States)

Singh, Arpita; Panting, Robert J.; Varma, Ashok; Saijo, Tomomi; Waldron, Kevin J.; Jong, Ambrose; Ngamskulrungroj, Popchai; Chang, Yun C.; Rutherford, Julian C.; Kwon-Chung, Kyung J.

2013-01-01

ABSTRACT Urease in Cryptococcus neoformans plays an important role in fungal dissemination to the brain and causing meningoencephalitis. Although urea is not required for synthesis of apourease encoded by URE1, the available nitrogen source affected the expression of URE1 as well as the level of the enzyme activity. Activation of the apoenzyme requires three accessory proteins, Ure4, Ure6, and Ure7, which are homologs of the bacterial urease accessory proteins UreD, UreF, and UreG, respectively. A yeast two-hybrid assay showed positive interaction of Ure1 with the three accessory proteins encoded by URE4, URE6, and URE7. Metalloproteomic analysis of cryptococcal lysates using inductively coupled plasma mass spectrometry (ICP-MS) and a biochemical assay of urease activity showed that, as in many other organisms, urease is a metallocentric enzyme that requires nickel transported by Nic1 for its catalytic activity. The Ure7 accessory protein (bacterial UreG homolog) binds nickel likely via its conserved histidine-rich domain and appears to be responsible for the incorporation of Ni2+ into the apourease. Although the cryptococcal genome lacks the bacterial UreE homolog, Ure7 appears to combine the functions of bacterial UreE and UreG, thus making this pathogen more similar to that seen with the plant system. Brain invasion by the ure1, ure7, and nic1 mutant strains that lack urease activity was significantly less effective in a mouse model. This indicated that an activated urease and not the Ure1 protein was responsible for enhancement of brain invasion and that the factors required for urease activation in C. neoformans resemble those of plants more than those of bacteria. PMID:23653445

Effect of urease inhibitor application rate and rainfall on ammonia emissions from beef manure

Science.gov (United States)

Social, economic, and environmental factors have prompted the desire to reduce global atmospheric ammonia emissions. A research project was conducted to assess the efficacy of the urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT) for reducing ammonia emissions from simulated open-lot beef...

Mua (HP0868) Is a Nickel-Binding Protein That Modulates Urease Activity in Helicobacter pylori

Science.gov (United States)

Benoit, Stéphane L.; Maier, Robert J.

2011-01-01

A novel mechanism aimed at controlling urease expression in Helicobacter pylori in the presence of ample nickel is described. Higher urease activities were observed in an hp0868 mutant (than in the wild type) in cells supplemented with nickel, suggesting that the HP0868 protein (herein named Mua for modulator of urease activity) represses urease activity when nickel concentrations are ample. The increase in urease activity in the Δmua mutant was linked to an increase in urease transcription and synthesis, as shown by quantitative real-time PCR, SDS-PAGE, and immunoblotting against UreAB. Increased urease synthesis was also detected in a Δmua ΔnikR double mutant strain. The Δmua mutant was more sensitive to nickel toxicity but more resistant to acid challenge than was the wild-type strain. Pure Mua protein binds 2 moles of Ni2+ per mole of dimer. Electrophoretic mobility shift assays did not reveal any binding of Mua to the ureA promoter or other selected promoters (nikR, arsRS, 5′ ureB-sRNAp). Previous yeast two-hybrid studies indicated that Mua and RpoD may interact; however, only a weak interaction was detected via cross-linking with pure components and this could not be verified by another approach. There was no significant difference in the intracellular nickel level between wild-type and mua mutant cells. Taken together, our results suggest the HP0868 gene product represses urease transcription when nickel levels are high through an as-yet-uncharacterized mechanism, thus counterbalancing the well-described NikR-mediated activation. PMID:21505055

Extraction of an urease-active organo-complex from soil.

Science.gov (United States)

Burns, R. G.; El-Sayed, M. H.; Mclaren, A. D.

1972-01-01

Description of an extraction from a Dublin clay loam soil of a colloidal organic matter complex that is urease active and, by X-ray analysis, free of clays. Urease activity in the clay-free precipitates, as in the soil, was not destroyed by the activity of an added proteolytic enzyme, pronase. This is attributed to the circumstance that native soil urease resides in organic colloidal particles with pores large enough for water, urea, ammonia, and carbon dioxide to pass freely, but nevertheless small enough to exclude pronase.

Preparation of crosslinked enzyme aggregates (CLEAs) of acid urease with urethanase activity and their application.

Science.gov (United States)

Zhang, Qian; Zha, Xiaohong; Zhou, Nandi; Tian, Yaping

2016-04-01

An acid urease from Providencia rettgeri JN-B815 was purified via ultrasonication, ethanol precipitation, and DEAE ion-exchange column chromatography. It was found that the enzyme exhibits not only urease activity, but also urethanase activity, which made it possible to reduce EC already existed or would produce and its precursor urea at the same time. Then, crosslinked enzyme aggregates of P. rettgeri urease (PRU-CLEAs) were prepared using genipin as crosslinking agent. The purification process of acid urease, the effects of genipin concentration, and crosslinking time on PRU-CLEAs activity were investigated. The crosslinking was performed at pH 4.5 for 2.5 h, using 0.3% genipin as crosslinking agent, and 0.3 g · L(-1) bovine serum albumin as protein feeder. Using the obtained PRU-CLEAs, the removal rate of urea was up to 9.31 mg · L(-1) · h(-1). The removal rate of urea was still up to 7.56 mg · L(-1) · h(-1) after PRU-CLEAs was re-used for 6 times. When PRU-CLEAs were applied in a batch stirred and membrane reactor, the removal rate of urea in rice wine reached 5.16 mg · L(-1) · h(-1) and the removal rate of EC was 9.21 μg · L(-1) · h(-1). Furthermore, the treatment with PRU-CLEAs revealed no significant change of volatile flavor substances in Chinese rice wine. Thus PRU-CLEAs have great potential in the elimination of EC in Chinese rice wine. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ureases as a target for the treatment of gastric and urinary infections.

Science.gov (United States)

Follmer, C

2010-05-01

Urease is known to be a major contributor to pathologies induced by Helicobacter pylori and Proteus species. In H pylori, urease allows the bacteria to survive in an acidic gastric environment during colonisation, playing an important role in the pathogenesis of gastric and peptic ulcers. Ureolytic activity also results in the production of ammonia in close proximity to the gastric epithelium, causing cell damage and inflammation. In the case of Proteus species (notably Proteus mirabilis) infection, stones are formed due to the presence of ammonia and carbon dioxide released by urease action. In addition, the ammonia released is able to damage the glycosaminoglycan layer, which protects the urothelial surface against bacterial infection. In this context, the administration of urease inhibitors may be an effective therapy for urease-dependent pathogenic bacteria. This is a review of the role of ureases in H pylori and Proteus species infections, focussing on the biochemical and clinical aspects of the most promising and/or potent urease inhibitors for the treatment of gastric and urinary tract infections.

Resposta do arroz irrigado ao uso de inibidor de urease em plantio direto e convencional Response of rice to the use of urease inhibitor in no-tillage and conventional

Directory of Open Access Journals (Sweden)

Mara Grohs

2011-04-01

Full Text Available O objetivo do presente trabalho foi avaliar a volatilização de N-NH3 e a resposta do arroz irrigado ao uso de ureia com inibidor de urease em dois sistemas de cultivo, direto e convencional. Para tanto, desenvolveu-se um experimento em campo, no ano agrícola 2008/09, na UFSM em Santa Maria/RS. O delineamento utilizado foi de blocos ao acaso em esquema bifatorial (2x5, sendo o fator A constituído por ureia e ureia revestida com B e Cu (inibidor de urease e o fator B composto por diferentes intervalos de entrada de água (0, 3, 6, 9, 12 dias após a aplicação das fontes de nitrogênio (N. Os resultados demonstram que o inibidor de urease retarda e diminui a conversão de N para NH3, reduzindo as perdas por volatilização, comparativamente à ureia sem inibidor. Entre os sistemas, as perdas são potencializadas no sistema plantio direto. O inibidor de urease não traz benefícios à produtividade em qualquer um dos sistemas de cultivo utilizados e o estresse causado na planta de arroz pelo atraso no início da irrigação é mais prejudicial do que as perdas causadas pela volatilização de N-NH3.The objective of this work was to measure the N-NH3 volatilization and the response of irrigated rice to the use of urea with urease inhibitor in two cropping systems, no-tillage and conventional. For this, an experiment in field was performed in the crop year 2008/09, at the UFSM in Santa Maria/RS. A random block in factorial scheme (2x5, with the factor A consisting of two nitrogen (N sources, urea and urea coated with B and Cu (urease inhibitor and the factor B consisting of different intervals of water intake (0, 3, 6, 9, 12 days after the application of N sources. The results demonstrated that the urease inhibitor slows and decreases the conversion of N to NH3, reducing the losses by volatilization, comparatively to urea without inhibitor. Between the systems, the losses were increased in the no-tillage system. The urease inhibitor does not add

Impedimetric Urea Biosensor Based on Modified Gold Electrode with Urease Immobilized on Glutathione Layer

OpenAIRE

Houcine BARHOUMI; Abderrazak MAAREF; Nicole JAFFREZIC-RENAULT

2014-01-01

In this work, a glutathione (GSH) modified gold microelectrode was used for the covalent immobilization of urease biomolecules via the glutaraldehyde-coupling agent. The self- assembled monolayers (SAMs) onto the gold surface was investigated by using the electrochemical impedance spectroscopy measurements (EIS). Before urease grafting, a significant interaction was noticed between urea and the glutathione layer by forming hydrogen bonds. The H-NMR analysis was carried out to highlight the po...

Allicin from garlic inhibits the biofilm formation and urease activity of Proteus mirabilis in vitro.

Science.gov (United States)

Ranjbar-Omid, Mahsa; Arzanlou, Mohsen; Amani, Mojtaba; Shokri Al-Hashem, Seyyedeh Khadijeh; Amir Mozafari, Nour; Peeri Doghaheh, Hadi

2015-05-01

Several virulence factors contribute to the pathogenesis of Proteus mirabilis. This study determined the inhibitory effects of allicin on urease, hemolysin and biofilm of P. mirabilis ATCC 12453 and its antimicrobial activity against 20 clinical isolates of P. mirabilis. Allicin did not inhibit hemolysin, whereas it did inhibit relative urease activity in both pre-lysed (half-maximum inhibitory concentration, IC50 = 4.15 μg) and intact cells (IC50 = 21 μg) in a concentration-dependent manner. Allicin at sub-minimum inhibitory concentrations (2-32 μg mL(-1)) showed no significant effects on the growth of the bacteria (P > 0.05), but it reduced biofilm development in a concentration-dependent manner (P mirabilis isolates were determined to be 128 and 512 μg mL(-1), respectively. The results suggest that allicin could have clinical applications in controlling P. mirabilis infections. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Antioxidant, antimicrobial and urease inhibiting activities of methanolic extracts from Cyphostemma digitatum stem and roots.

Science.gov (United States)

Khan, Rasool; Saif, Abdullah Qasem; Quradha, Mohammed Mansour; Ali, Jawad; Rauf, Abdur; Khan, Ajmal

2016-01-01

Cyphostemma digitatum stem and roots extracts were investigated for antioxidant, antimicrobial, urease inhibition potential and phytochemical analysis. Phytochemical screening of the roots and stem extract revealed the presence of secondary metabolites including flavonoids, alkaloids, coumarins, saponins, terpenoids, tannins, carbohydrates/reducing sugars and phenolic compounds. The methanolic extracts of the roots displayed highest antioxidant activity (93.518%) against DPPH while the crude methanolic extract of the stem showed highest antioxidant activity (66.163%) at 100 μg/mL concentration. The methanolic extracts of both stem and roots were moderately active or even found to be less active against the selected bacterial and fungal strains (Tables S2 and S3). The roots extract (methanol) showed significant urease enzyme inhibition activity (IC50 = 41.2 ± 0.66; 0.2 mg/mL) while the stem extract was found moderately active (IC50 = 401.1 ± 0.58; 0.2 mg/mL) against thiourea (IC50 = 21.011; 0.2 mg/mL).

Enzymatic, immunological and phylogenetic characterization of Brucella suis urease

Directory of Open Access Journals (Sweden)

Sriranganathan Nammalwar

2008-07-01

Full Text Available Abstract Background The sequenced genomes of the Brucella spp. have two urease operons, ure-1 and ure-2, but there is evidence that only one is responsible for encoding an active urease. The present work describes the purification and the enzymatic and phylogenomic characterization of urease from Brucella suis strain 1330. Additionally, the urease reactivity of sera from patients diagnosed with brucellosis was examined. Results Urease encoded by the ure-1 operon of Brucella suis strain 1330 was purified to homogeneity using ion exchange and hydrophobic interaction chromatographies. The urease was purified 51-fold with a recovery of 12% of the enzyme activity and 0.24% of the total protein. The enzyme had an isoelectric point of 5, and showed optimal activity at pH 7.0 and 28–35°C. The purified enzyme exhibited a Michaelis-Menten saturation kinetics with a Km of 5.60 ± 0.69 mM. Hydroxyurea and thiourea are competitive inhibitors of the enzyme with Ki of 1.04 ± 0.31 mM and 26.12 ± 2.30 mM, respectively. Acetohydroxamic acid also inhibits the enzyme in a competitive way. The molecular weight estimated for the native enzyme was between 130–135 kDa by gel filtration chromatography and 157 ± 7 kDa using 5–10% polyacrylamide gradient non-denaturing gel. Only three subunits in SDS-PAGE were identified: two small subunits of 14,000 Da and 15,500 Da, and a major subunit of 66,000 Da. The amino terminal sequence of the purified large subunit corresponded to the predicted amino acid sequence encoded by ureC1. The UreC1 subunit was recognized by sera from patients with acute and chronic brucellosis. By phylogenetic and cluster structure analyses, ureC1 was related to the ureC typically present in the Rhizobiales; in contrast, the ureC2 encoded in the ure-2 operon is more related to distant species. Conclusion We have for the first time purified and characterized an active urease from B. suis. The enzyme was characterized at the kinetic

Potentiometric urea biosensor based on an immobilised fullerene-urease bio-conjugate.

Science.gov (United States)

Saeedfar, Kasra; Heng, Lee Yook; Ling, Tan Ling; Rezayi, Majid

2013-12-06

A novel method for the rapid modification of fullerene for subsequent enzyme attachment to create a potentiometric biosensor is presented. Urease was immobilized onto the modified fullerene nanomaterial. The modified fullerene-immobilized urease (C60-urease) bioconjugate has been confirmed to catalyze the hydrolysis of urea in solution. The biomaterial was then deposited on a screen-printed electrode containing a non-plasticized poly(n-butyl acrylate) (PnBA) membrane entrapped with a hydrogen ionophore. This pH-selective membrane is intended to function as a potentiometric urea biosensor with the deposition of C60-urease on the PnBA membrane. Various parameters for fullerene modification and urease immobilization were investigated. The optimal pH and concentration of the phosphate buffer for the urea biosensor were 7.0 and 0.5 mM, respectively. The linear response range of the biosensor was from 2.31 × 10-3 M to 8.28 × 10-5 M. The biosensor's sensitivity was 59.67 ± 0.91 mV/decade, which is close to the theoretical value. Common cations such as Na+, K+, Ca2+, Mg2+ and NH4+ showed no obvious interference with the urea biosensor's response. The use of a fullerene-urease bio-conjugate and an acrylic membrane with good adhesion prevented the leaching of urease enzyme and thus increased the stability of the urea biosensor for up to 140 days.

Metallochaperone UreG serves as a new target for design of urease inhibitor: A novel strategy for development of antimicrobials.

Directory of Open Access Journals (Sweden)

Xinming Yang

2018-01-01

Full Text Available Urease as a potential target of antimicrobial drugs has received considerable attention given its versatile roles in microbial infection. Development of effective urease inhibitors, however, is a significant challenge due to the deeply buried active site and highly specific substrate of a bacterial urease. Conventionally, urease inhibitors are designed by either targeting the active site or mimicking substrate of urease, which is not efficient. Up to now, only one effective inhibitor-acetohydroxamic acid (AHA-is clinically available, but it has adverse side effects. Herein, we demonstrate that a clinically used drug, colloidal bismuth subcitrate, utilizes an unusual way to inhibit urease activity, i.e., disruption of urease maturation process via functional perturbation of a metallochaperone, UreG. Similar phenomena were also observed in various pathogenic bacteria, suggesting that UreG may serve as a general target for design of new types of urease inhibitors. Using Helicobacter pylori UreG as a showcase, by virtual screening combined with experimental validation, we show that two compounds targeting UreG also efficiently inhibited urease activity with inhibitory concentration (IC50 values of micromolar level, resulting in attenuated virulence of the pathogen. We further demonstrate the efficacy of the compounds in a mammalian cell infection model. This study opens up a new opportunity for the design of more effective urease inhibitors and clearly indicates that metallochaperones involved in the maturation of important microbial metalloenzymes serve as new targets for devising a new type of antimicrobial drugs.

Metallochaperone UreG serves as a new target for design of urease inhibitor: A novel strategy for development of antimicrobials.

Science.gov (United States)

Yang, Xinming; Koohi-Moghadam, Mohamad; Wang, Runming; Chang, Yuen-Yan; Woo, Patrick C Y; Wang, Junwen; Li, Hongyan; Sun, Hongzhe

2018-01-01

Urease as a potential target of antimicrobial drugs has received considerable attention given its versatile roles in microbial infection. Development of effective urease inhibitors, however, is a significant challenge due to the deeply buried active site and highly specific substrate of a bacterial urease. Conventionally, urease inhibitors are designed by either targeting the active site or mimicking substrate of urease, which is not efficient. Up to now, only one effective inhibitor-acetohydroxamic acid (AHA)-is clinically available, but it has adverse side effects. Herein, we demonstrate that a clinically used drug, colloidal bismuth subcitrate, utilizes an unusual way to inhibit urease activity, i.e., disruption of urease maturation process via functional perturbation of a metallochaperone, UreG. Similar phenomena were also observed in various pathogenic bacteria, suggesting that UreG may serve as a general target for design of new types of urease inhibitors. Using Helicobacter pylori UreG as a showcase, by virtual screening combined with experimental validation, we show that two compounds targeting UreG also efficiently inhibited urease activity with inhibitory concentration (IC)50 values of micromolar level, resulting in attenuated virulence of the pathogen. We further demonstrate the efficacy of the compounds in a mammalian cell infection model. This study opens up a new opportunity for the design of more effective urease inhibitors and clearly indicates that metallochaperones involved in the maturation of important microbial metalloenzymes serve as new targets for devising a new type of antimicrobial drugs.

Contribution of Urease to Colonization by Shiga Toxin-Producing Escherichia coli

Science.gov (United States)

Steyert, Susan R.

2012-01-01

Shiga toxin-producing Escherichia coli (STEC) is a food-borne pathogen with a low infectious dose that colonizes the colon in humans and can cause severe clinical manifestations such as hemolytic-uremic syndrome. The urease enzyme, encoded in the STEC chromosome, has been demonstrated to act as a virulence factor in other bacterial pathogens. The NH3 produced as urease hydrolyzes urea can aid in buffering bacteria in acidic environments as well as provide an easily assimilated source of nitrogen that bacteria can use to gain a metabolic advantage over intact microflora. Here, we explore the role of urease in STEC pathogenicity. The STEC urease enzyme exhibited maximum activity near neutral pH and during the stationary-growth phase. Experiments altering growth conditions performed with three phylogenetically distinct urease-positive strains demonstrated that the STEC ure gene cluster is inducible by neither urea nor pH but does respond to nitrogen availability. Quantitative reverse transcription-PCR (qRT-PCR) data indicate that nitrogen inhibits the transcriptional response. The deletion of the ure gene locus was constructed in STEC strain 88-0643, and the ure mutant was used with the wild-type strain in competition experiments in mouse models to examine the contribution of urease. The wild-type strain was twice as likely to survive passage through the acidic stomach and demonstrated an enhanced ability to colonize the intestinal tract compared to the ure mutant strain. These in vivo experiments reveal that, although the benefit STEC gains from urease expression is modest and not absolutely required for colonization, urease can contribute to the pathogenicity of STEC. PMID:22665380

The Structure of Urease Activation Complexes Examined by Flexibility Analysis, Mutagenesis, and Small-angle X-ray Scattering Approaches

International Nuclear Information System (INIS)

Quiroz, Soledad; Sukuru, Sai Chetan K.; Hausinger, Robert P.; Kuhn, Leslie A.; Heller, William T

2008-01-01

Conformational changes of Klebsiella aerogenes urease apoprotein (UreABC) 3 induced upon binding of the UreD and UreF accessory proteins were examined by a combination of flexibility analysis, mutagenesis, and small-angle X-ray scattering (SAXS). ProFlex analysis of urease provided evidence that the major domain of UreB can move in a hinge-like motion to account for prior chemical cross-linking results. Rigidification of the UreB hinge region, accomplished through a G11P mutation, reduced the extent of urease activation, in part by decreasing the nickel content of the mutant enzyme, and by sequestering a portion of the urease apoprotein in a novel activation complex that includes all of the accessory proteins. SAXS analyses of urease, (UreABC-UreD) 3 , and (UreABC-UreDF) 3 confirm that UreD and UreF bind near UreB at the periphery of the (UreAC) 3 structure. This study supports an activation model in which a domain-shifted UreB conformation in (UreABC-UreDF) 3 allows CO 2 and nickel ions to gain access to the nascent active site

Design, synthesis, in vitro Evaluation and docking studies on dihydropyrimidine-based urease inhibitors.

Science.gov (United States)

Iftikhar, Fatima; Ali, Yousaf; Ahmad Kiani, Farooq; Fahad Hassan, Syed; Fatima, Tabeer; Khan, Ajmal; Niaz, Basit; Hassan, Abbas; Latif Ansari, Farzana; Rashid, Umer

2017-10-01

In our previous report, we have identified 3,4-dihydropyrimidine scaffold as promising class of urease inhibitor in a structure based virtual screen (SBVS) experiment. In present study, we attempted to optimize the scaffold by varying C-5 substituent. The elongation of the C-5 chain was achieved by the reaction of C-5 ester with hydrazine leading to C-5 carbohydrazides which were further used as building blocks for the synthesis of fifteen new compounds having diverse moieties. A significantly higher in vitro urease inhibitory activity with IC 50 values in submicromolar range was observed for semithiocarbazide derivatives (4a-c, 0.58-0.79µM) and isatin Schiff base derivative 5a (0.23µM). Docking analysis suggests that the synthesized compounds were anchored well in the catalytic site and extending to the entrance of binding pocket and thus restrict the mobility of the flap by interacting with its key amino acid residues. The overall results of urease inhibition have shown that these compounds can be further optimized and developed as lead urease inhibitors. Copyright © 2017 Elsevier Inc. All rights reserved.

Biocolloids with ordered urease multilayer shells as enzymatic reactors.

Science.gov (United States)

Lvov, Y; Caruso, F

2001-09-01

The preparation of biocolloids with organized enzyme-containing multilayer shells for exploitation as colloidal enzymatic nanoreactors is described. Urease multilayers were assembled onto submicrometer-sized polystyrene spheres by the sequential adsorption of urease and polyelectrolyte, in a predetermined order, utilizing electrostatic interactions for layer growth. The catalytic activity of the biocolloids increased proportionally with the number of urease layers deposited on the particles, demonstrating that biocolloid particles with tailored enzymatic activities can be produced. It was further found that precoating the latex spheres with nanoparticles (40-nm silica or 12-nm magnetite) enhanced both the stability (with respect to adsorption) and enzymatic activity of the urease multilayers. The presence of the magnetite nanoparticle coating also provided a magnetic function that allowed the biocolloids to be easily and rapidly separated with a permanent magnet. The fabrication of such colloids opens new avenues for the application of bioparticles and represents a promising route for the creation of complex catalytic particles.

Comparison of four urease-dependent tests of detecting HP infection

International Nuclear Information System (INIS)

Han Yuan; Huang Gang; Zhu Cuiying; Ling Liqun

2001-01-01

Objective: The aim of this study is to compare the four urease-dependent tests of detecting Hp infection. The authors used following method: 1) rapid urease test (RUT), 2) 14 C urea breath test ( 14 C-UBT), 3) 13 C urea breath test which is measured by with infrared spectrometry ( 13 C-UBT1), 4) 13 C urea breath test with mass spectrometry ( 13 C-UBT). Methods: 54 patients underwent RUT, 14 C-UBT, 13 C-UBT1, 13 C-UBT2 respectively. Results: Sensitivity and specificity, accurate rate, positive predictive value (PPV), negative predictive value (NPV), respectively, were as follows: RUT (82.1%, 80%, 81.5%, 91.4%, 63.2%), 14 C-UBT (97.4%, 100%, 98.1%, 100%, 93.8%), 13 C-UBT1 (100%, 93.3%, 98.1%, 97.5%, 100%), 13 C-UBT2 (100%, 86.7%, 96.3%, 95.1%, 100%), PPV of four tests are not significantly different (P>0.05). Conclusion: Four urease-dependent tests are high sensitive and accurate methods for detecting Hp infection. UBT is an ideal tool for diagnosis, screen and follow-up of Hp infection

Potentiometric Urea Biosensor Based on an Immobilised Fullerene-Urease Bio-Conjugate

Directory of Open Access Journals (Sweden)

Kasra Saeedfar

2013-12-01

Full Text Available A novel method for the rapid modification of fullerene for subsequent enzyme attachment to create a potentiometric biosensor is presented. Urease was immobilized onto the modified fullerene nanomaterial. The modified fullerene-immobilized urease (C60-urease bioconjugate has been confirmed to catalyze the hydrolysis of urea in solution. The biomaterial was then deposited on a screen-printed electrode containing a non-plasticized poly(n-butyl acrylate (PnBA membrane entrapped with a hydrogen ionophore. This pH-selective membrane is intended to function as a potentiometric urea biosensor with the deposition of C60-urease on the PnBA membrane. Various parameters for fullerene modification and urease immobilization were investigated. The optimal pH and concentration of the phosphate buffer for the urea biosensor were 7.0 and 0.5 mM, respectively. The linear response range of the biosensor was from 2.31 × 10−3 M to 8.28 × 10−5 M. The biosensor’s sensitivity was 59.67 ± 0.91 mV/decade, which is close to the theoretical value. Common cations such as Na+, K+, Ca2+, Mg2+ and NH4+ showed no obvious interference with the urea biosensor’s response. The use of a fullerene-urease bio-conjugate and an acrylic membrane with good adhesion prevented the leaching of urease enzyme and thus increased the stability of the urea biosensor for up to 140 days.

Negative Effect of Proton-pump Inhibitors (PPIs) on Helicobacter pylori Growth, Morphology, and Urease Test and Recovery after PPI Removal--An In vitro Study.

Science.gov (United States)

Saniee, Parastoo; Shahreza, Somayeh; Siavoshi, Farideh

2016-04-01

Proton-pump inhibitor (PPI) consumption does lead to false-negative results of Helicobacter pylori diagnostic tests such as biopsy culture and rapid urease test (RUT). Helicobacter pylori isolates from 112 dyspeptic patients with (56.5%) or without (43.5%) PPI consumption were recruited for examining the negative effects of omeprazole (OMP), lansoprazole (LPZ), and pantoprazole (PAN) on H. pylori viability, morphology, and urease, in vitro. The effect of a sublethal concentration of OMP on bacterial features and their recovery after removal of OMP was also assessed. Of 112 culture-positive gastric biopsies, 87.5% were RUT positive and 12.5% RUT negative. There was a significant correlation between negative RUT results and PPI consumption (p urease of 90.3% of isolates between 0 and 40 minutes and 54.4% between 20 and 40 minutes, respectively. PAN did not inhibit H. pylori growth and urease. Three 3-day (9 days) consecutive subcultures of H. pylori on brucella blood agar (BBA) supplemented with OMP resulted in reduced bacterial viability (1+), compared with control (4+), change of spiral morphology to coccoid, and reduction in pink color intensity in urea agar. Bacterial growth (1+), morphology, and urease test did not improve after the first 3-day and second 3-day (6 days) subcultures on BBA. However, relative recovery occurred after the third 3-day (9 days) subculture and complete recovery was observed after the fourth 3-day (12 days) subculture, as confluent growth (4+), 100% spiral cells, and strong urease test. Proton-pump Inhibitors exert transient negative effects on H. pylori viability, morphology, and urease test. Accordingly, cessation of PPI consumption at least 12 days before endoscopy could help avoiding false-negative results of H. pylori diagnostic tests. © 2015 John Wiley & Sons Ltd.

TiO₂ beads and TiO₂-chitosan beads for urease immobilization.

Science.gov (United States)

Ispirli Doğaç, Yasemin; Deveci, Ilyas; Teke, Mustafa; Mercimek, Bedrettin

2014-09-01

The aim of the present study is to synthesize TiO2 beads for urease immobilization. Two different strategies were used to immobilize the urease on TiO2 beads. In the first method (A), urease enzyme was immobilized onto TiO2 beads by adsorption and then crosslinking. In the second method (B), TiO2 beads were coated with chitosan-urease mixture. To determine optimum conditions of immobilization, different parameters were investigated. The parameters of optimization were initial enzyme concentration (0.5; 1; 1.5; 2mg/ml), alginate concentration (1; 2; 3%), glutaraldehyde concentration (1; 2; 3% v/v) and chitosan concentration (2; 3; 4 mg/ml). The optimum enzyme concentrations were determined as 1.5mg/ml for A and 1.0mg/ml for B. The other optimum conditions were found 2.0% (w/v) for alginate concentration (both A and B); 3.0mg/ml for chitosan concentration (B) and 2.0% (v/v) for glutaraldehyde concentration (A). The optimum temperature (20-60°C), optimum pH (3.0-10.0), kinetic parameters, thermal stability (4-70°C), pH stability (4.0-9.0), operational stability (0-230 min) and reusability (20 times) were investigated for characterization. The optimum temperatures were 30°C (A), 40°C (B) and 35°C (soluble). The temperature profiles of the immobilized ureases were spread over a large area. The optimum pH values for the soluble urease and immobilized urease prepared by using methods (A) and (B) were found to be 7.5, 7.0, 7.0, respectively. The thermal stabilities of immobilized enzyme sets were studied and they maintained 50% activity at 65°C. However, at this temperature free urease protected only 15% activity. Copyright © 2014 Elsevier B.V. All rights reserved.

Novel organophosphorus scaffolds of urease inhibitors obtained by substitution of Morita-Baylis-Hillman adducts with phosphorus nucleophiles.

Science.gov (United States)

Ntatsopoulos, Vassilis; Vassiliou, Stamatia; Macegoniuk, Katarzyna; Berlicki, Łukasz; Mucha, Artur

2017-06-16

The reactivity of Morita-Baylis-Hillman allyl acetates was employed to introduce phosphorus-containing functionalities to the side chain of the cinnamic acid conjugated system by nucleophilic displacement. The proximity of two acidic groups, the carboxylate and phosphonate/phosphinate groups, was necessary to form interactions in the active site of urease by recently described inhibitor frameworks. Several organophosphorus scaffolds were obtained and screened for inhibition of the bacterial urease, an enzyme that is essential for survival of urinary and gastrointestinal tract pathogens. α-Substituted phosphonomethyl- and 2-phosphonoethyl-cinnamate appeared to be the most potent and were further optimized. As a result, one of the most potent organophosphorus inhibitors of urease, α-phosphonomethyl-p-methylcinnamic acid, was identified, with K i  = 0.6 μM for Sporosarcina pasteurii urease. High complementarity to the enzyme active site was achieved with this structure, as any further modifications significantly decreased its affinity. Finally, this work describes the challenges faced in developing ligands for urease. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Silencing urease: A key evolutionary step that facilitated the adaptation of Yersinia pestis to the flea-borne transmission route

Science.gov (United States)

Chouikha, Iman; Hinnebusch, B. Joseph

2014-01-01

The arthropod-borne transmission route of Yersinia pestis, the bacterial agent of plague, is a recent evolutionary adaptation. Yersinia pseudotuberculosis, the closely related food-and water-borne enteric species from which Y. pestis diverged less than 6,400 y ago, exhibits significant oral toxicity to the flea vectors of plague, whereas Y. pestis does not. In this study, we identify the Yersinia urease enzyme as the responsible oral toxin. All Y. pestis strains, including those phylogenetically closest to the Y. pseudotuberculosis progenitor, contain a mutated ureD allele that eliminated urease activity. Restoration of a functional ureD was sufficient to make Y. pestis orally toxic to fleas. Conversely, deletion of the urease operon in Y. pseudotuberculosis rendered it nontoxic. Enzymatic activity was required for toxicity. Because urease-related mortality eliminates 30–40% of infective flea vectors, ureD mutation early in the evolution of Y. pestis was likely subject to strong positive selection because it significantly increased transmission potential. PMID:25453069

Silencing urease: a key evolutionary step that facilitated the adaptation of Yersinia pestis to the flea-borne transmission route.

Science.gov (United States)

Chouikha, Iman; Hinnebusch, B Joseph

2014-12-30

The arthropod-borne transmission route of Yersinia pestis, the bacterial agent of plague, is a recent evolutionary adaptation. Yersinia pseudotuberculosis, the closely related food-and water-borne enteric species from which Y. pestis diverged less than 6,400 y ago, exhibits significant oral toxicity to the flea vectors of plague, whereas Y. pestis does not. In this study, we identify the Yersinia urease enzyme as the responsible oral toxin. All Y. pestis strains, including those phylogenetically closest to the Y. pseudotuberculosis progenitor, contain a mutated ureD allele that eliminated urease activity. Restoration of a functional ureD was sufficient to make Y. pestis orally toxic to fleas. Conversely, deletion of the urease operon in Y. pseudotuberculosis rendered it nontoxic. Enzymatic activity was required for toxicity. Because urease-related mortality eliminates 30-40% of infective flea vectors, ureD mutation early in the evolution of Y. pestis was likely subject to strong positive selection because it significantly increased transmission potential.

Biological evaluation and molecular docking of baicalin and scutellarin as Helicobacter pylori urease inhibitors.

Science.gov (United States)

Yu, Xiao-Dan; Zheng, Rong-Bo; Xie, Jian-Hui; Su, Ji-Yan; Huang, Xiao-Qi; Wang, Yong-Hong; Zheng, Yi-Feng; Mo, Zhi-Zhun; Wu, Xiao-Li; Wu, Dian-Wei; Liang, Ye-er; Zeng, Hui-Fang; Su, Zi-Ren; Huang, Ping

2015-03-13

Helicobacter pylori urease, since thiol reagents (L,D-dithiothreitol, L-cysteine and glutathione) abolished the inhibitory action and competitive active site Ni(2+) binding inhibitors (boric acid and sodium fluoride) carried invalid effect. Molecular docking study further supported the structure-activity analysis and indicated that baicalin and scutellarin interacted with the key residues Cys321 located on the mobile flap through S-H·π interaction, but did not interact with active site Ni(2+). Moreover, Baicalin (at 0.59-1.05 mM concentrations) and scutellarin (at 0.23-0.71 mM concentrations) did not exhibit significant cytotoxicity to GES-1. Baicalin and scutellarin were non-competitive inhibitors targeting sulfhydryl groups especially Cys321 around the active site of Helicobacter pylori urease, representing potential to be good candidate for future research as urease inhibitor for treatment of Helicobacter pylori infection. Furthermore, our work gave additional scientific support to the use of Scutellaria baicalensis in traditional Chinese medicine (TCM) to treat gastrointestinal disorders. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Kinetics and Mechanism Study of Competitive Inhibition of Jack-Bean Urease by Baicalin

Science.gov (United States)

Tan, Lirong; Su, Jiyan; Wu, Dianwei; Yu, Xiaodan; Su, Zuqing; Wu, Xiaoli; Kong, Songzhi; Lai, Xiaoping; Lin, Ji; Su, Ziren

2013-01-01

Baicalin (BA) is the principal component of Radix Scutellariae responsible for its pharmacological activity. In this study, kinetics and mechanism of inhibition by BA against jack-bean urease were investigated for its therapeutic potential. It was revealed that the IC50 of BA against jack-bean urease was 2.74 ± 0.51 mM, which was proved to be a competitive and concentration-dependent inhibition with slow-binding progress curves. The rapid formation of initial BA-urease complex with an inhibition constant of K i = 3.89 × 10−3 mM was followed by a slow isomerization into the final complex with an overall inhibition constant of K i* = 1.47 × 10−4 mM. High effectiveness of thiol protectors against BA inhibition indicated that the strategic role of the active-site sulfhydryl group of the urease was involved in the blocking process. Moreover, the inhibition of BA was proved to be reversible due to the fact that urease could be reactivated by dithiothreitol but not reactant dilution. Molecular docking assay suggested that BA made contacts with the important activating sulfhydryl group Cys-592 residues and restricted the mobility of the active-site flap. Taken together, it could be deduced that BA was a competitive inhibitor targeting thiol groups of urease in a slow-binding manner both reversibly and concentration-dependently, serving as a promising urease inhibitor for treatments on urease-related diseases. PMID:24198731

TiO2 beads and TiO2-chitosan beads for urease immobilization

International Nuclear Information System (INIS)

Ispirli Doğaç, Yasemin; Deveci, İlyas; Teke, Mustafa; Mercimek, Bedrettin

2014-01-01

The aim of the present study is to synthesize TiO 2 beads for urease immobilization. Two different strategies were used to immobilize the urease on TiO 2 beads. In the first method (A), urease enzyme was immobilized onto TiO 2 beads by adsorption and then crosslinking. In the second method (B), TiO 2 beads were coated with chitosan-urease mixture. To determine optimum conditions of immobilization, different parameters were investigated. The parameters of optimization were initial enzyme concentration (0.5; 1; 1.5; 2 mg/ml), alginate concentration (1; 2; 3%), glutaraldehyde concentration (1; 2; 3% v/v) and chitosan concentration (2; 3; 4 mg/ml). The optimum enzyme concentrations were determined as 1.5 mg/ml for A and 1.0 mg/ml for B. The other optimum conditions were found 2.0% (w/v) for alginate concentration (both A and B); 3.0 mg/ml for chitosan concentration (B) and 2.0% (v/v) for glutaraldehyde concentration (A). The optimum temperature (20-60 °C), optimum pH (3.0-10.0), kinetic parameters, thermal stability (4–70 °C), pH stability (4.0-9.0), operational stability (0-230 min) and reusability (20 times) were investigated for characterization. The optimum temperatures were 30 °C (A), 40 °C (B) and 35 °C (soluble). The temperature profiles of the immobilized ureases were spread over a large area. The optimum pH values for the soluble urease and immobilized urease prepared by using methods (A) and (B) were found to be 7.5, 7.0, 7.0, respectively. The thermal stabilities of immobilized enzyme sets were studied and they maintained 50% activity at 65 °C. However, at this temperature free urease protected only 15% activity. - Highlights: • TiO 2 and TiO 2 -chitosan beads for urease immobilization have been prepared and characterized. • The beads used in this work are good matrices for the immobilization of urease. • The immobilized urease was shown to have good properties and stabilities (pH and thermal stability, operational stability). • The 50

Safety and efficacy of E coli enterotoxin adjuvant for urease-based rectal immunization against Helicobacter pylori.

Science.gov (United States)

Sougioultzis, Stavros; Lee, Cynthia K; Alsahli, Mazen; Banerjee, Subhas; Cadoz, Michel; Schrader, Robert; Guy, Bruno; Bedford, Philip; Monath, Thomas P; Kelly, Ciaran P; Michetti, Pierre

2002-12-13

Low dose E. coli heat-labile enterotoxin (LT), delivered orally or enterically, has been used as an adjuvant for Helicobacter pylori (H. pylori) urease in healthy adults. In this study we aim to test the safety and adjuvant efficacy of LT delivered rectally together with recombinant H. pylori urease. Eighteen healthy adults without present or past H. pylori infection were enrolled in a double blind, randomized, ascending dose study to receive either urease (60 mg), or urease (60 mg) + LT (5 or 25 microg). The immunization preparation was administered per rectum on days 0, 14 and 28. Serum, stool and saliva anti-urease and anti-LT IgG and IgA antibodies (Abs) were measured and urease-specific and LT-specific antigen secreting cells (ASCs) were counted in peripheral blood at baseline and 7 (ASC counts) or 14 days (antibody levels) after each dosing. Peripheral blood lymphoproliferation assays were also performed at baseline and at the end of the study. Rectally delivered urease and LT were well tolerated. Among the 12 subjects assigned to urease+LT, 2 (16.7%) developed anti-urease IgG Abs, 1 (8.3%) developed anti-urease IgA Abs, and 3 (25%) showed urease-specific IgA(+) ASCs. Immune responses to LT were more vigorous, especially in subjects exposed to 5 microg LT. In the urease+ 5 microg LT group, anti-LT IgG and IgA Abs developed in 60 and 80% of the subjects, respectively, while LT-specific IgG(+) and IgA(+) ASCs were detected in all subjects. The magnitude of the anti-LT response was much higher than the response to urease. No IgA anti-urease or anti-LT Abs were detected in stool or saliva and lymphocyte proliferative responses to urease were unsatisfactory. In conclusion, rectal delivery of 5 microg LT is safe and induces vigorous systemic anti-LT immune responses. Further studies are needed to determine if LT can be an effective adjuvant for rectally delivered antigens.

Structural and transcriptional characterization of a novel member of the soybean urease gene family.

Science.gov (United States)

Wiebke-Strohm, Beatriz; Ligabue-Braun, Rodrigo; Rechenmacher, Ciliana; De Oliveira-Busatto, Luisa Abruzzi; Carlini, Célia Regina; Bodanese-Zanettini, Maria Helena

2016-04-01

In plants, ureases have been related to urea degradation, to defense against pathogenic fungi and phytophagous insects, and to the soybean-Bradyrhizobium japonicum symbiosis. Two urease isoforms have been described for soybean: the embryo-specific, encoded by Eu1 gene, and the ubiquitous urease, encoded by Eu4. A third urease-encoding locus exists in the completed soybean genome. The gene was designated Eu5 and the putative product of its ORF as SBU-III. Phylogenetic analysis shows that 41 plant, moss and algal ureases have diverged from a common ancestor protein, but ureases from monocots, eudicots and ancient species have evolved independently. Genomes of ancient organisms present a single urease-encoding gene and urease-encoding gene duplication has occurred independently along the evolution of some eudicot species. SBU-III has a shorter amino acid sequence, since many gaps are found when compared to other sequences. A mutation in a highly conserved amino acid residue suggests absence of ureolytic activity, but the overall protein architecture remains very similar to the other ureases. The expression profile of urease-encoding genes in different organs and developmental stages was determined by RT-qPCR. Eu5 transcripts were detected in seeds one day after dormancy break, roots of young plants and embryos of developing seeds. Eu1 and Eu4 transcripts were found in all analyzed organs, but Eu4 expression was more prominent in seeds one day after dormancy break whereas Eu1 predominated in developing seeds. The evidence suggests that SBU-III may not be involved in nitrogen availability to plants, but it could be involved in other biological role(s). Copyright © 2016 Elsevier Masson SAS. All rights reserved.

2-(Hetero(aryl)methylene)hydrazine-1-carbothioamides as potent urease inhibitors.

Science.gov (United States)

Saeed, Aamer; Imran, Aqeel; Channar, Pervaiz A; Shahid, Mohammad; Mahmood, Wajahat; Iqbal, Jamshed

2015-02-01

A small series of 2-(hetero(aryl)methylene) hydrazine-1-carbothioamides including two aryl derivatives was synthesized and tested for their inhibitory activity against urease. Compound (E)-2-(Furan-2-ylmethylene) hydrazine-1-carbothioamide (3f), having a furan ring, was the most potent inhibitor of urease with an IC50 value of 0.58 μM. Molecular modeling was carried out through docking the designed compounds into the urease binding site to predict whether these derivatives have analogous binding mode to the urease inhibitors. The study revealed that all of the tested compounds bind with both metal atoms at the active site of the enzyme. The aromatic ring of the compounds forms ionic interactions with the residues, Ala(440), Asp(494), Ala(636), and Met(637). © 2014 John Wiley & Sons A/S.

Epiberberine, a natural protoberberine alkaloid, inhibits urease of Helicobacter pylori and jack bean: Susceptibility and mechanism.

Science.gov (United States)

Tan, Lihua; Li, Cailan; Chen, Hanbin; Mo, Zhizhun; Zhou, Jiangtao; Liu, Yuhong; Ma, Zhilin; Xu, Yuyao; Yang, Xiaobo; Xie, Jianhui; Su, Ziren

2017-12-15

In our previous study, Rhizoma Coptidis extract was found to exert more potent inhibitory effect than its major component berberine towards urease from Helicobacter pylori (HPU) and jack bean (JBU). In continuation of our work, the present study was designed to further comparatively investigate the urease inhibitory activities of five major protoberberine alkaloids in Rhizoma Coptidis, namely berberine, palmatine, coptisine, epiberberine, jateorhizine to identify the bioactive constituent, and illuminate the potential mechanism of action. Results indicated that the five protoberberine alkaloids acted as concentration-dependent inactivators of urease with IC 50 values ranging between 3.0 and 5087μM for HPU and 2.3->10,000μM for JBU, respectively. Notably, epiberberine (EB) was found to be the most potent inhibitor against both ureases with IC 50 values of 3.0±0.01μM for HPU and 2.3±0.01μM for JBU, which was more effective than the standard urease inhibitor, acetohydroxamic acid (83±0.01μM for HPU and 22±0.01μM for JBU, respectively). Further kinetic analysis revealed that the type of EB inhibition against HPU was slow-binding and uncompetitive, with K i of 10.6±0.01μM, while slow-binding and competitive against JBU with K i of 4.6±0.01μM. Addition of thiol reagents, such as l-cysteine, glutathione and dithiothreitol, significantly abolished the inhibition, while Ni 2+ competitive inhibitors, boric acid and sodium fluoride, synergetically inhibited urease with EB, indicating the obligatory role of the active site sulfhydryl group for the inhibition. In addition, binding of EB with the urease proved to be reversible, as about 65% and 90% enzymatic activity of HPU and JBU, respectively, could be restored by dithiothreitol application. These findings highlighted the potential role of Rhizoma Coptidis protoberberine alkaloids, especially EB, as a lead urease inhibitor in the treatment of diseases associated with ureolytic bacteria. Thus, EB had good

Adherence of urease-induced crystals to rat bladder epithelium.

Science.gov (United States)

Grenabo, L; Hedelin, H; Pettersson, S

1988-01-01

Apart from urine supersaturation with respect to struvite and calcium phosphate caused by urease-producing microorganisms, retention of formed crystals in the urinary tract is necessary for the formation of infection stones. This study was performed to investigate the role of the mucous coat lining the urothelium in the adhesion of urease-induced crystals. Removal of this glycosaminoglycan-containing layer from rat bladders increased the adherence of struvite and calcium phosphate crystals 5-6 times compared to that in intact rat bladders. Heparin completely restored the antiadherence capacity while chondroitin sulphate had a very weak restorative effect and human urine had no restorative effect. These findings support the view that the mucous coat is of importance in preventing retention of urease-induced crystals.

Synthesis of urease hybrid nanoflowers and their enhanced catalytic properties.

Science.gov (United States)

Somturk, Burcu; Yilmaz, Ismail; Altinkaynak, Cevahir; Karatepe, Aslıhan; Özdemir, Nalan; Ocsoy, Ismail

2016-05-01

Increasing numbers of materials have been extensively used as platforms for enzyme immobilization to enhance catalytic activity and stability. Although stability of enzyme was accomplished with immobilization approaches, activity of the most of the enzymes was declined after immobilization. Herein, we synthesize the flower shaped-hybrid nanomaterials called hybrid nanoflower (HNF) consisting of urease enzyme and copper ions (Cu(2+)) and report a mechanistic elucidation of enhancement in both activity and stability of the HNF. We demonstrated how experimental factors influence morphology of the HNF. We proved that the HNF (synthesized from 0.02mgmL(-1) urease in 10mM PBS (pH 7.4) at +4°C) exhibited the highest catalytic activity of ∼2000% and ∼4000% when stored at +4°C and RT, respectively compared to free urease. The highest stability was also achieved by this HNF by maintaining 96.3% and 90.28% of its initial activity within storage of 30 days at +4°C and RT, respectively. This dramatically enhanced activity is attributed to high surface area, nanoscale-entrapped urease and favorable urease conformation of the HNF. The exceptional catalytic activity and stability properties of HNF can be taken advantage of to use it in fields of biomedicine and chemistry. Copyright © 2015 Elsevier Inc. All rights reserved.

A novel nanobody against urease activity of Helicobacter pylori.

Science.gov (United States)

Ardekani, Leila Safaee; Gargari, Seyed Latif Mousavi; Rasooli, Iraj; Bazl, Masoumeh Rajabi; Mohammadi, Mohammad; Ebrahimizadeh, Walead; Bakherad, Hamid; Zare, Hamed

2013-09-01

Helicobacter pylori infection is associated with gastritis and in some cases with gastric and duodenal ulcers, and even adenocarcinoma. Antibiotic therapy has significant limitations, such as the high cost and the emergence of antibiotic-resistant strains, generating the need for new treatments. The administration of antibody against H. pylori is a new effective therapeutic strategy. In this study, we successfully developed a single-variable domain of heavy chain antibody against recombinant UreC. A VHH phagemid library was constructed from immune camel heavy chain antibodies. The nanobodies were displayed on M13 phage. Library selection was performed against UreC recombinant protein. A specific single-variable domain of heavy chain antibody against UreC was screened in five rounds of panning. The nanobody with the highest score in the phage ELISA was selected for soluble expression. The nanobody was purified with a nickel-nitrilotriacetic acid (Ni-NTA) column and confirmed with sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting. Affinity, specificity, and urease inhibitory properties of the nanobody were assayed. Here we showed the isolation and purification of a specific nanobody with high affinity against UreC recombinant protein that can inhibit urease activity. The isolated UreC nanobody can specifically detect and bind to UreC and inhibit urease activity. This nanobody could be a novel class of treatment measure against H. pylori infection. Copyright © 2013 International Society for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Avaliação de fontes de urease na amonização de fenos de Brachiaria brizantha com dois teores de umidade Evaluation of urease sources in the ammoniation of Brachiaria brizantha hays with two moisture levels

Directory of Open Access Journals (Sweden)

Liandra Maria Abaker Bertipaglia

2005-04-01

moisture contents (15 or 30% moisture, and three urease source (Brachiaria decumbens hay, elephantgrass (Pennisetum purpureum, leucena (Leucaena leucocephala was evaluated. The crude protein (CP, soluble nitrogen fraction (A, borate phosphate true protein fractions (B1 and B2, potentially degradable protein fraction (B3, acid detergent insoluble protein (C were analyzed. The NDF, ADF, cellulose, hemicellulose and lignin contents and in vitro dry matter digestibility (IVDMD were analyzed. The experiment was conducted according to a completely randomized block design with 10 treatments (two control, 15 and 30% moisture, without urea and urease; two controls, 15 and 30% moisture, with urea and urease; six combinations of urease source and moisture levels, with three replicates. Ammoniation increased CP, and A fractions of the hays baled with different moisture contents associated to urease source; however urea application did not affect the B1, and B2 values. The B3 and C values decreased due to the urea application. The ammoniation of the high moisture hay (30%, associated or not to urease source reduced NDF. External urease source did not affect the cell wall contents of the brachiaria hay, compared to the urea treatment without external urease. Ammoniation with urea had a unconsistent effect on the ADF, and cellulose contents of the hay. The treatment did not affect the lignin content of the hay. The urea application with 15 or 30% moisture increased soluble nitrogen of Brachiaria brizantha hay and decreased the unavailable nitrogen to the ruminant.

Relationship between ureB Sequence Diversity, Urease Activity and Genotypic Variations of Different Helicobacter pylori Strains in Patients with Gastric Disorders.

Science.gov (United States)

Ghalehnoei, Hossein; Ahmadzadeh, Alireza; Farzi, Nastaran; Alebouyeh, Masoud; Aghdaei, Hamid Asadzadeh; Azimzadeh, Pendram; Molaei, Mahsa; Zali, Mohammad Reza

2016-01-01

Association of the severity of Helicobacter pylori induced diseases with virulence entity of the colonized strains was proven in some studies. Urease has been demonstrated as a potent virulence factor for H. pylori. The main aim of this study was investigation of the relationships of ureB sequence diversity, urease activity and virulence genotypes of different H. pylori strains with histopathological changes of gastric tissue in infected patients suffering from different gastric disorders. Analysis of the virulence genotypes in the isolated strains indicated significant associations between the presence of severe active gastritis and cagA+ (P = 0.039) or cagA/iceA1 genotypes (P = 0.026), and intestinal metaplasia and vacA m1 (P = 0.008) or vacA s1/m2 (P = 0.001) genotypes. Our results showed a 2.4-fold increased risk of peptic ulcer (95% CI: 0.483-11.93), compared with gastritis, in the infected patients who had dupA positive strains; however this association was not statistically significant. The results of urease activity showed a significant mean difference between the isolated strains from patients with PUD and NUD (P = 0.034). This activity was relatively higher among patients with intestinal metaplasia. Also a significant association was found between the lack of cagA and increased urease activity among the isolated strains (P = 0.036). While the greatest sequence variation of ureB was detected in a strain from a patient with intestinal metaplasia, the sole determined amino acid change in UreB sequence (Ala201Thr, 30%), showed no influence on urease activity. In conclusion, the supposed role of H. pylori urease to form peptic ulcer and advancing of intestinal metaplasia was postulated in this study. Higher urease activity in the colonizing H. pylori strains that present specific virulence factors was indicated as a risk factor for promotion of histopathological changes of gastric tissue that advance gastric malignancy.

Effect of paddy urease inhibitors on fate of 15N-urea

International Nuclear Information System (INIS)

Chen Wei; Lu Wanfang

1997-01-01

Urea applied to the paddy field rapidly released ammonium (NH 4 + ) through hydrolysis. The released NH 4 + -N usually reached to a maximum value 2 days after the application. The maximum value was found to be lower and delay 1 day when a mixture of urea and urease inhibitors was applied. Based on 15 N tracing in the urea, it was found that the two urease inhibitors, phenylphosphordiamidate (PPD) and N-(N-butyl) thiophosphoric triamine (NBPT), could enhance the efficiency of urea utilization by rice plants due to more absorption and also stimulated rice growth. The grain yields were higher in the treatments applied with the mixture containing PPD or NBPT, especially at high N level, than that in the treatment applied with urea only. However, the urea inhibitor, hydroquinone (HQ), had far less effect than PPD and NBPT in the experiment. The application of rice straw was found to reduce the urea-N absorption by rice plants but increase its residue in the soil

Large scale screening of commonly used Iranian traditional medicinal plants against urease activity

Directory of Open Access Journals (Sweden)

Nabati Farzaneh

2012-10-01

Full Text Available Abstract Background and purpose of the study H. pylori infection is an important etiologic impetus usually leading to gastric disease and urease enzyme is the most crucial role is to protect the bacteria in the acidic environment of the stomach. Then urease inhibitors would increase sensitivity of the bacteria in acidic medium. Methods 137 Iranian traditional medicinal plants were examined against Jack bean urease activity by Berthelot reaction. Each herb was extracted using 50% aqueous methanol. The more effective extracts were further tested and their IC50 values were determined. Results 37 plants out of the 137 crude extracts revealed strong urease inhibitory activity (more than 70% inhibition against urease activity at 10 mg/ml concentration. Nine of the whole studied plants crude extracts were found as the most effective with IC50 values less than 500 μg/ml including; Rheum ribes, Sambucus ebulus, Pistachia lentiscus, Myrtus communis, Areca catechu, Citrus aurantifolia, Myristica fragrans, Cinnamomum zeylanicum and Nicotiana tabacum. Conclusions The most potent urease inhibitory was observed for Sambucus ebulus and Rheum ribes extracts with IC50 values of 57 and 92 μg/ml, respectively.

Impedimetric Urea Biosensor Based on Modified Gold Electrode with Urease Immobilized on Glutathione Layer

Directory of Open Access Journals (Sweden)

Houcine BARHOUMI

2014-05-01

Full Text Available In this work, a glutathione (GSH modified gold microelectrode was used for the covalent immobilization of urease biomolecules via the glutaraldehyde-coupling agent. The self- assembled monolayers (SAMs onto the gold surface was investigated by using the electrochemical impedance spectroscopy measurements (EIS. Before urease grafting, a significant interaction was noticed between urea and the glutathione layer by forming hydrogen bonds. The H-NMR analysis was carried out to highlight the possibility of having a covalent link between urea and the GSH deposited layer. In addition, contact angle measurements were carried out to determine the hydrophobic/hydrophilic feature of the modified gold surface electrode. After urease immobilization a stable and high sensitive impedimetric urea biosensors was obtained with a sensitivity of 8.73´10- 8 W-1mM-1 for the low concentrations range and a sensitivity of 7.03´10-9 W-1mM-1 for the high concentrations range.

Urease activity in dental plaque and saliva of children during a three-year study period and its relationship with other caries risk factors.

Science.gov (United States)

Morou-Bermudez, E; Elias-Boneta, A; Billings, R J; Burne, R A; Garcia-Rivas, V; Brignoni-Nazario, V; Suarez-Perez, E

2011-11-01

Bacterial urease activity in dental plaque and in saliva generates ammonia, which can increase the plaque pH and can protect acid-sensitive oral bacteria. Recent cross-sectional studies suggest that reduced ability to generate ammonia from urea in dental plaque can be an important caries risk factor. In spite of this proposed important clinical role, there is currently no information available regarding important clinical aspects of oral ureolysis in children. The objective of this study was to evaluate the distribution and pattern of urease activity in the dental plaque and in the saliva of children during a three-year period, and to examine the relationship of urease with some important caries risk factors. A longitudinal study was conducted with repeated measures over a three-year period on a panel of 80 children, aged 3-6 years at recruitment. The dynamics of change in urease activity were described and associated with clinical, biological, and behavioural caries risk factors. Urease activity in plaque showed a trend to remain stable during the study period and was negatively associated with sugar consumption (P<0.05). Urease activity in unstimulated saliva increased with age, and it was positively associated with the levels of mutans streptococci in saliva and with the educational level of the parents (P<0.05). The results of this study reveal interesting and complex interactions between oral urease activity and some important caries risk factors. Urease activity in saliva could be an indicator of mutans infection in children. Copyright © 2011 Elsevier Ltd. All rights reserved.

Selective antibacterial activity of patchouli alcohol against Helicobacter pylori based on inhibition of urease.

Science.gov (United States)

Yu, Xiao-Dan; Xie, Jian-Hui; Wang, Yong-Hong; Li, Yu-Cui; Mo, Zhi-Zhun; Zheng, Yi-Feng; Su, Ji-Yan; Liang, Ye-er; Liang, Jin-Zhi; Su, Zi-Ren; Huang, Ping

2015-01-01

The aim of this study is to evaluate the antibacterial activity and urease inhibitory effects of patchouli alcohol (PA), the bioactive ingredient isolated from Pogostemonis Herba, which has been widely used for the treatment of gastrointestinal disorders. The activities of PA against selected bacteria and fungi were determined by agar dilution method. It was demonstrated that PA exhibited selective antibacterial activity against Helicobacter pylori, without influencing the major normal gastrointestinal bacteria. Noticeably, the antibacterial activity of PA was superior to that of amoxicillin, with minimal inhibition concentration value of 78 µg/mL. On the other hand, PA inhibited ureases from H.pylori and jack bean in concentration-dependent fashion with IC50 values of 2.67 ± 0.79 mM and 2.99 ± 0.41 mM, respectively. Lineweaver-Burk plots indicated that the type of inhibition was non-competitive against H.pylori urease whereas uncompetitive against jack bean urease. Reactivation of PA-inactivated urease assay showed DL-dithiothreitol, the thiol reagent, synergistically inactivated urease with PA instead of enzymatic activity recovery. In conclusion, the selective H.pylori antibacterial activity along with urease inhibitory potential of PA could make it a possible drug candidate for the treatment of H.pylori infection. Copyright © 2014 John Wiley & Sons, Ltd.

Effectiveness of urease inhibition on the abatement of ammonia, nitrous oxide and nitric oxide emissions in a non-irrigated Mediterranean barley field.

Science.gov (United States)

Abalos, Diego; Sanz-Cobena, Alberto; Misselbrook, Thomas; Vallejo, Antonio

2012-09-01

Urea is considered the cheapest and most commonly used form of inorganic N fertilizer worldwide. However, its use is associated with emissions of ammonia (NH(3)), nitrous oxide (N(2)O) and nitric oxide (NO), which have both economic and environmental impact. Urease activity inhibitors have been proposed as a means to reduce NH(3) emissions, although limited information exists about their effect on N(2)O and NO emissions. In this context, a field experiment was carried out with a barley crop (Hordeum vulgare L.) under Mediterranean conditions to test the effectiveness of the urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT) on reducing these gaseous N losses from surface applied urea. Crop yield, soil mineral N concentrations, dissolved organic carbon (DOC), denitrification potential, NH(3), N(2)O and NO fluxes were measured during the growing season. The inclusion of the inhibitor reduced NH(3) emissions in the 30 d following urea application by 58% and net N(2)O and NO emissions in the 95 d following urea application by 86% and 88%, respectively. NBPT addition also increased grain yield by 5% and N uptake by 6%, although neither increase was statistically significant. Under the experimental conditions presented here, these results demonstrate the potential of the urease inhibitor NBPT in abating NH(3), N(2)O and NO emissions from arable soils fertilized with urea, slowing urea hydrolysis and releasing lower concentrations of NH(4)(+) to the upper soil layer. Copyright © 2012 Elsevier Ltd. All rights reserved.

Purification, crystallization and preliminary X-ray analysis of urease from pigeon pea (Cajanus cajan)

Energy Technology Data Exchange (ETDEWEB)

Balasubramanian, Anuradha; Ponnuraj, Karthe, E-mail: pkarthe@hotmail.com [Centre of Advanced Study in Crystallography and Biophysics, University of Madras, Guindy Campus, Chennai 600 025 (India)

2008-07-01

Urease from pigeon pea was purified and crystallized and X-ray diffraction data were collected at 2.5 Å resolution. Urease is a seed protein that is common to most Leguminosae. It also occurs in many bacteria, fungi and several species of yeast. Urease catalyzes the hydrolysis of urea to ammonia and carbon dioxide, thus allowing organisms to use exogenous and internally generated urea as a nitrogen source. Urease from pigeon pea seeds has been purified to electrophoretic homogeneity using a series of steps involving ammonium sulfate fractionation, acid precipitation, ion-exchange and size-exclusion chromatography techniques. The pigeon pea urease was crystallized and the resulting crystals diffracted to 2.5 Å resolution. The crystals belong to the rhombohedral space group R32, with unit-cell parameters a = b = 176.29, c = 346.44 Å.

Urease from seeds of 'Citrullus vulgaris'. The effect of chemical agents and ionizing radiations

Energy Technology Data Exchange (ETDEWEB)

Hargreaves, A B; de Souza Marcondes, N; Elias, C A [Rio de Janeiro Univ. (Brazil). Instituto de Biofisica

1976-09-30

The effect of the urea analogs acetanide and hidroxi-urea on the enzyme kinetic of urease obtained from seeds of 'Citrullus vulgaris' fruits has been studied. The action of the sulphydryl reagents and the enzyme and the effect of x-rays and the protective action of the cysteamine are also studied. Acetamide has no effect on urease kinetic. Hydroxi-urea acts as a competitive inhibitor of urease. Spectrophotometric experiments suggest that the studied urease decomposes hidroxi-urea with liberation of hydroxilamine. The sulphydril reagent, p-hydroxi-mercuribenzoate inhibts the enzyme. Cysteine and dithiotreitol reactivate the enzyme activity in no more than 50% even when excess of the substances is used. Urease is very sensitive to x-rays. Cysteamine acts as a protective agent of the enzyme. Dithiotreitol reinforces this protective action.

Purification, crystallization and preliminary X-ray analysis of urease from pigeon pea (Cajanus cajan)

International Nuclear Information System (INIS)

Balasubramanian, Anuradha; Ponnuraj, Karthe

2008-01-01

Urease from pigeon pea was purified and crystallized and X-ray diffraction data were collected at 2.5 Å resolution. Urease is a seed protein that is common to most Leguminosae. It also occurs in many bacteria, fungi and several species of yeast. Urease catalyzes the hydrolysis of urea to ammonia and carbon dioxide, thus allowing organisms to use exogenous and internally generated urea as a nitrogen source. Urease from pigeon pea seeds has been purified to electrophoretic homogeneity using a series of steps involving ammonium sulfate fractionation, acid precipitation, ion-exchange and size-exclusion chromatography techniques. The pigeon pea urease was crystallized and the resulting crystals diffracted to 2.5 Å resolution. The crystals belong to the rhombohedral space group R32, with unit-cell parameters a = b = 176.29, c = 346.44 Å

Synthesis, biological evaluation and molecular docking of N-phenyl thiosemicarbazones as urease inhibitors.

Science.gov (United States)

Hameed, Abdul; Khan, Khalid Mohammed; Zehra, Syeda Tazeen; Ahmed, Ramasa; Shafiq, Zahid; Bakht, Syeda Mahwish; Yaqub, Muhammad; Hussain, Mazhar; de la Vega de León, Antonio; Furtmann, Norbert; Bajorath, Jürgen; Shad, Hazoor Ahmad; Tahir, Muhammad Nawaz; Iqbal, Jamshed

2015-08-01

Urease is an important enzyme which breaks urea into ammonia and carbon dioxide during metabolic processes. However, an elevated activity of urease causes various complications of clinical importance. The inhibition of urease activity with small molecules as inhibitors is an effective strategy for therapeutic intervention. Herein, we have synthesized a series of 19 benzofurane linked N-phenyl semithiocarbazones (3a-3s). All the compounds were screened for enzyme inhibitor activity against Jack bean urease. The synthesized N-phenyl thiosemicarbazones had varying activity levels with IC50 values between 0.077 ± 0.001 and 24.04 ± 0.14 μM compared to standard inhibitor, thiourea (IC50 = 21 ± 0.11 μM). The activities of these compounds may be due to their close resemblance of thiourea. A docking study with Jack bean urease (PDB ID: 4H9M) revealed possible binding modes of N-phenyl thiosemicarbazones. Copyright © 2015 Elsevier Inc. All rights reserved.

Expression of urease by Haemophilus influenzae during human respiratory tract infection and role in survival in an acid environment

Science.gov (United States)

2011-01-01

Background Nontypeable Haemophilus influenzae is a common cause of otitis media in children and lower respiratory tract infection in adults with chronic obstructive pulmonary disease (COPD). Prior studies have shown that H. influenzae expresses abundant urease during growth in the middle ear of the chinchilla and in pooled human sputum, suggesting that expression of urease is important for colonization and infection in the hostile environments of the middle ear and in the airways in adults. Virtually nothing else is known about the urease of H. influenzae, which was characterized in the present study. Results Analysis by reverse transcriptase PCR revealed that the ure gene cluster is expressed as a single transcript. Knockout mutants of a urease structural gene (ureC) and of the entire ure operon demonstrated no detectable urease activity indicating that this operon is the only one encoding an active urease. The ure operon is present in all strains tested, including clinical isolates from otitis media and COPD. Urease activity decreased as nitrogen availability increased. To test the hypothesis that urease is expressed during human infection, purified recombinant urease C was used in ELISA with pre acquisition and post infection serum from adults with COPD who experienced infections caused by H. influenzae. A total of 28% of patients developed new antibodies following infection indicating that H. influenzae expresses urease during airway infection. Bacterial viability assays performed at varying pH indicate that urease mediates survival of H. influenzae in an acid environment. Conclusions The H. influenzae genome contains a single urease operon that mediates urease expression and that is present in all clinical isolates tested. Nitrogen availability is a determinant of urease expression. H. influenzae expresses urease during human respiratory tract infection and urease is a target of the human antibody response. Expression of urease enhances viability in an acid

Purification, crystallization and preliminary X-ray analysis of urease from jack bean (Canavalia ensiformis)

International Nuclear Information System (INIS)

Balasubramanian, Anuradha; Ponnuraj, Karthe

2009-01-01

Jack bean urease was purified and crystallized and X-ray diffraction data were collected to 2.05 Å resolution. Plant urease is a seed protein that is common in most legumes. It is also common in many bacteria and fungi and several species of yeast. Urease allows organisms to use exogenous and internally generated urea as a nitrogen source by catalyzing the hydrolysis of urea to ammonia and carbon dioxide. Urease from jack bean meal was purified to electrophoretic homogeneity using a series of steps involving acetone precipitation and size-exclusion and ion-exchange chromatography. The jack bean urease was crystallized and the resulting crystals diffracted to 2.05 Å resolution using synchrotron radiation. The crystals belonged to the hexagonal space group P6 3 22, with unit-cell parameters a = b = 138.57, c = 198.36 Å

Limited effectiveness of over-the-counter plant preparations used for the treatment of urinary tract infections as inhibitors of the urease activity from Staphylococcus saprophyticus.

Science.gov (United States)

Deutch, C E

2017-05-01

Urease is a key virulence factor for the Gram-positive urinary tract pathogen Staphylococcus saprophyticus and a potential target for antimicrobial therapy. The enzyme from S. saprophyticus is unusual in that it does not contain cysteine at the active site. The aims of this study were to test 14 over-the-counter plant preparations as inhibitors of this urease and to determine whether they can prevent the increase in pH that normally occurs in bacterial cultures containing urea. Urease activity was measured colorimetrically by the formation of ammonium ions. The green tea and Uva-Ursi preparations reduced urease activity in a soluble extract of S. saprophyticus by more than 75%. Two herbal mixtures were weakly inhibitory and reduced activity by about 25%, but the other products had little or no effect. The green tea and Uva-Ursi extracts also inhibited urease activity in whole cells by more than 75%. One of the herbal products (WishGarden UTI) showed some inhibition of urease activity but the other (UTI Clear) did not. The green tea and Uva-Ursi preparations prevented the increase in pH that normally occurs when S. saprophyticus is grown in an artificial urine medium, but this was due primarily to bacterial death. The WishGarden UTI preparation could partially delay the pH increase while allowing some cells to remain viable. These results indicate that only a few of the commercially available over-the-counter plant preparations commonly used for the treatment of urinary tract infections (UTIs) can inhibit the urease activity from S. saprophyticus. While over-the-counter plant preparations may be considered an alternative to traditional antibiotics for the treatment of UTIs, they should be used with caution and a product should be matched to the properties of the virulence factors of the bacterial pathogen involved. © 2017 The Society for Applied Microbiology.

Helicobacter pylori gene silencing in vivo demonstrates urease is essential for chronic infection.

Science.gov (United States)

Debowski, Aleksandra W; Walton, Senta M; Chua, Eng-Guan; Tay, Alfred Chin-Yen; Liao, Tingting; Lamichhane, Binit; Himbeck, Robyn; Stubbs, Keith A; Marshall, Barry J; Fulurija, Alma; Benghezal, Mohammed

2017-06-01

Helicobacter pylori infection causes chronic active gastritis that after many years of infection can develop into peptic ulceration or gastric adenocarcinoma. The bacterium is highly adapted to surviving in the gastric environment and a key adaptation is the virulence factor urease. Although widely postulated, the requirement of urease expression for persistent infection has not been elucidated experimentally as conventional urease knockout mutants are incapable of colonization. To overcome this constraint, conditional H. pylori urease mutants were constructed by adapting the tetracycline inducible expression system that enabled changing the urease phenotype of the bacteria during established infection. Through tight regulation we demonstrate that urease expression is not only required for establishing initial colonization but also for maintaining chronic infection. Furthermore, successful isolation of tet-escape mutants from a late infection time point revealed the strong selective pressure on this gastric pathogen to continuously express urease in order to maintain chronic infection. In addition to mutations in the conditional gene expression system, escape mutants were found to harbor changes in other genes including the alternative RNA polymerase sigma factor, fliA, highlighting the genetic plasticity of H. pylori to adapt to a changing niche. The tet-system described here opens up opportunities to studying genes involved in the chronic stage of H. pylori infection to gain insight into bacterial mechanisms promoting immune escape and life-long infection. Furthermore, this genetic tool also allows for a new avenue of inquiry into understanding the importance of various virulence determinants in a changing biological environment when the bacterium is put under duress.

Helicobacter pylori gene silencing in vivo demonstrates urease is essential for chronic infection.

Directory of Open Access Journals (Sweden)

Aleksandra W Debowski

2017-06-01

Full Text Available Helicobacter pylori infection causes chronic active gastritis that after many years of infection can develop into peptic ulceration or gastric adenocarcinoma. The bacterium is highly adapted to surviving in the gastric environment and a key adaptation is the virulence factor urease. Although widely postulated, the requirement of urease expression for persistent infection has not been elucidated experimentally as conventional urease knockout mutants are incapable of colonization. To overcome this constraint, conditional H. pylori urease mutants were constructed by adapting the tetracycline inducible expression system that enabled changing the urease phenotype of the bacteria during established infection. Through tight regulation we demonstrate that urease expression is not only required for establishing initial colonization but also for maintaining chronic infection. Furthermore, successful isolation of tet-escape mutants from a late infection time point revealed the strong selective pressure on this gastric pathogen to continuously express urease in order to maintain chronic infection. In addition to mutations in the conditional gene expression system, escape mutants were found to harbor changes in other genes including the alternative RNA polymerase sigma factor, fliA, highlighting the genetic plasticity of H. pylori to adapt to a changing niche. The tet-system described here opens up opportunities to studying genes involved in the chronic stage of H. pylori infection to gain insight into bacterial mechanisms promoting immune escape and life-long infection. Furthermore, this genetic tool also allows for a new avenue of inquiry into understanding the importance of various virulence determinants in a changing biological environment when the bacterium is put under duress.

Helicobacter ganmani sp nov., a urease-negative anaerobe isolated from the intestines of laboratory mice

DEFF Research Database (Denmark)

Robertson, B.R.; O'Rourke, J.L.; Vandamme, P.

2001-01-01

, isolates possessed single, bipolar, unsheathed flagella and were urease-negative. They were positive for oxidase and reduced nitrate to nitrite but did not hydrolyse hippurate or indoxyl acetate, grew on charcoal agar and were resistant to cephalothin. 16S rDNA sequences from four strains were determined...

Urease Plays an Important Role in the Chemotactic Motility of Helicobacter pylori in a Viscous Environment

OpenAIRE

Nakamura, Hiroki; Yoshiyama, Hironori; Takeuchi, Hiroaki; Mizote, Tomoko; Okita, Kiwamu; Nakazawa, Teruko

1998-01-01

Helicobacter pylori exhibits chemotactic responses to urea, flurofamide, acetohydroxamic acid, and sodium bicarbonate. In buffer, the chemotactic activities of a urease-positive strain were higher than those of the isogenic urease-negative strain. Moreover, the chemotactic activities of the urease-positive strain were increased in a viscous solution containing 3% polyvinylpyrrolidone, whereas those of the urease-negative mutant were not. These results are in accordance with the fact that the ...

METHOD OF SUPPRESSING GASTROINTESTINAL UREASE ACTIVITY

Science.gov (United States)

Visek, W.J.

1963-04-23

This patent shows a method of increasing the growth rate of chicks. Certain diacyl substituted ureas such as alloxan, murexide, and barbituric acid are added to their feed, thereby suppressing gastrointestinal urease activity and thus promoting growth. (AEC)

Urease plays an important role in the chemotactic motility of Helicobacter pylori in a viscous environment.

Science.gov (United States)

Nakamura, H; Yoshiyama, H; Takeuchi, H; Mizote, T; Okita, K; Nakazawa, T

1998-10-01

Helicobacter pylori exhibits chemotactic responses to urea, flurofamide, acetohydroxamic acid, and sodium bicarbonate. In buffer, the chemotactic activities of a urease-positive strain were higher than those of the isogenic urease-negative strain. Moreover, the chemotactic activities of the urease-positive strain were increased in a viscous solution containing 3% polyvinylpyrrolidone, whereas those of the urease-negative mutant were not. These results are in accordance with the fact that the mutant strain did not show swarming in motility agar regardless of having flagella. Incubation of the wild-type strain with flurofamide resulted in partial inhibition of the chemotactic activities in the viscous solution. In addition, incubation with acetohydroxamic acid, a low-molecular-weight, diffusible urease inhibitor, resulted in complete loss of chemotactic activity in the viscous solution. The inhibition of the chemotactic activity by urease inhibitors paralleled the inhibition of urease. The chemotactic activity of H. pylori was also inhibited by the proton carrier carbonyl cyanide m-chlorophenylhydrazone, showing that H. pylori utilizes proton motive force for motility. These results indicate that cytoplasmic urease plays an important role in the chemotactic motility of H. pylori under a condition that mimics the ecological niche of the bacterium, the gastric mucous layer.

Ureic nitrogen transformation in multi-layer soil columns treated with urease and nitrification inhibitors.

Science.gov (United States)

Giovannini, Camilla; Garcia-Mina, Josè M; Ciavatta, Claudio; Marzadori, Claudio

2009-06-10

The use of N-(n-butyl)thiophosphoric triamide (NBPT), as a urease inhibitor, is one of the most successful strategies utilized to increase the efficiency of urea-based fertilization. To date, NBPT has been added to the soil incorporated in fertilizers containing either urea or the inhibitor at a fixed percentage on the urea weight. The possibility of using NBPT physically separated from urea-based fertilizers could make its use more flexible. In particular, a granulated product containing NBPT could be utilized in soils treated with different urea-based fertilizers including livestock urine, the amount depending on soil characteristics and/or the urea source (e.g., mineral fertilizer, organo-mineral fertilizer, or animal slurry). In this study, a multilayer soil column device was used to investigate the influence of an experimental granular product (RV) containing NBPT and a garlic extract, combining the ability to protect NBPT by oxidation and nitrification inhibition activity, on (a) spatial variability of soil urease and nitrification activities and (b) timing of urea hydrolysis and mineral-N form accumulation (NO(2)(-), NO(3)(-), NH(4)(+)) in soil treated with urea. The results clearly demonstrated that RV can, effectively, inhibit the soil urease activity along the soil column profile up to 8-10 cm soil layer depth and that the inhibition power of RV was dependent on time and soil depth. However, nitrification activity is not significantly influenced by RV addition. In addition, the soil N transformations were clearly affected by RV; in fact, RV retarded urea hydrolysis and reduced the accumulation of NH(4)(+)-N and NO(2)(-)-N ions along the soil profile. The RV product was demonstrated to be an innovative additive able to modify some key ureic N trasformation processes correlated with the efficiency of the urea-based fertilization, in a soil column higher than 10 cm.

Incorporating a hybrid urease-carbon nanotubes sensitive nanofilm on capacitive field-effect sensors for urea detection.

Science.gov (United States)

Siqueira, José R; Molinnus, Denise; Beging, Stefan; Schöning, Michael J

2014-06-03

The ideal combination among biomolecules and nanomaterials is the key for reaching biosensing units with high sensitivity. The challenge, however, is to find out a stable and sensitive film architecture that can be incorporated on the sensor's surface. In this paper, we report on the benefits of incorporating a layer-by-layer (LbL) nanofilm of polyamidoamine (PAMAM) dendrimer and carbon nanotubes (CNTs) on capacitive electrolyte-insulator-semiconductor (EIS) field-effect sensors for detecting urea. Three sensor arrangements were studied in order to investigate the adequate film architecture, involving the LbL film with the enzyme urease: (i) urease immobilized directly onto a bare EIS [EIS-urease] sensor; (ii) urease atop the LbL film over the EIS [EIS-(PAMAM/CNT)-urease] sensor; and (iii) urease sandwiched between the LbL film and another CNT layer [EIS-(PAMAM/CNT)-urease-CNT]. The surface morphology of all three urea-based EIS biosensors was investigated by atomic force microscopy (AFM), while the biosensing abilities were studied by means of capacitance-voltage (C/V) and dynamic constant-capacitance (ConCap) measureaments at urea concentrations ranging from 0.1 mM to 100 mM. The EIS-urease and EIS-(PAMAM/CNT)-urease sensors showed similar sensitivity (~18 mV/decade) and a nonregular signal behavior as the urea concentration increased. On the other hand, the EIS-(PAMAM/CNT)-urease-CNT sensor exhibited a superior output signal performance and higher sensitivity of about 33 mV/decade. The presence of the additional CNT layer was decisive to achieve a urea based EIS sensor with enhanced properties. Such sensitive architecture demonstrates that the incorporation of an adequate hybrid enzyme-nanofilm as sensing unit opens new prospects for biosensing applications using the field-effect sensor platform.

Preparation of Glutaraldehyde Cross-Linked Chitosan Beads Under Microwave Irradiation and Properties of Urease Immobilized onto the Beads

Institute of Scientific and Technical Information of China (English)

LIANG Zupei; FENG Yaqing; MENG Shuxian; ZHANG Weihong

2005-01-01

The glutaraldehyde cross-linked chitosan beads were prepared under microwave irradiation and urease was immobilized onto the beads. The activity and the yield of enzyme activity of the immobilized urease were 10.83 U/g carrier and 47.7%, respectively. The optimum conditions of immobilization were 1% of glutaraldehyde volume fraction, 10 mg/g of urease/beads weight ratio, 24 h of the processing time and pH 6.5 of the reaction medium for immobilization. The properties of the immobilized urease were investigated and compared with those of the free enzyme. The optimum pH values were 6.5 and 7.0 for the immobilized and free urease, respectively. The optimum temperature was 60 ℃ for the free urease, while it shifted to 65 ℃ for the immobilized enzyme. The Michaelis constant K m was 9.1 mmol/L for the immobilized and 12.5 mmol/L for the free urease. The immobilized urease retained 40% of its initial enzyme activity even after 10 repeated uses. The immobilized urease stored at 4 ℃ retained 46% of its initial activity even after 35 d.

[Degradation of urea and ethyl carbamate in Chinese Rice wine by recombinant acid urease].

Science.gov (United States)

Zhou, Jianli; Kang, Zhen; Liu, Qingtao; Du, Guocheng; Chen, Jian

2016-01-01

Ethyl carbamate (EC) as a potential carcinogen commonly exists in traditional fermented foods. It is important eliminate urea that is the precursors of EC in many fermented foods, including Chinese Rice wine. On the basis of achieving high-level overexpression of food-grade ethanol-resistant acid urease, we studied the hydrolysis of urea and EC with the recombinant acid urease. Recombinant acid urease showed degraded urea in both the simulated system with ethanol and Chinese Rice wine (60 mg/L of urea was completely degraded within 25 h), indicating that the recombinant enzyme is suitable for the elimination of urea in Chinese Rice wine. Although recombinant acid urease also has degradation catalytic activity on EC, no obvious degradation of EC was observed. Further investigation results showed that the Km value for urea and EC of the recombinant acid urease was 0.7147 mmol/L and 41.32 mmol/L, respectively. The results provided theoretical foundation for realizing simultaneous degradation of urea and EC.

Armored Urease: Enzyme-Bioconjugated Poly(acrylamide) Hydrogel as a Storage and Sensing Platform.

Science.gov (United States)

Kunduru, Konda R; Kutcherlapati, S N Raju; Arunbabu, Dhamodaran; Jana, Tushar

2017-01-01

Jack bean urease is an important enzyme not only because of its numerous uses in medical and other fields but also because of its historical significance-the first enzyme to be crystallized and also the first nickel metalloenzyme. This enzyme hydrolyzes urea into ammonia and carbon dioxide; however, the stability of this enzyme at ambient temperature is a bottleneck for its applicability. To improve urease stability, it was immobilized on different substrates, particularly on polymeric hydrogels. In this study, the enzyme was coupled covalently with poly(acrylamide) hydrogel with an yield of 18μmol/cm 3 . The hydrogel served as the nanoarmor and protected the enzyme against denaturation. The enzyme immobilized on the polymer hydrogel showed no loss in activity for more than 30 days at ambient temperature, whereas free enzyme lost its activity within a couple of hours. The Michaelis-Menten constant (K m ) for free and immobilized urease were 0.0256 and 0.2589mM, respectively, on the first day of the study. The K m of the immobilized enzyme was approximately 10 times higher than that of the free enzyme. The hydrogel technique was also used to prepare light diffracting polymerized colloidal crystal array in which urease enzyme was covalently immobilized. This system was applied for the detection of mercury (Hg 2+ ) with the lower limit as 1ppb, which is below the maximum contaminant limit (2ppb) for mercury ions in water. The experimental details of these studies are presented in this chapter. © 2017 Elsevier Inc. All rights reserved.

Synthesis of 4-thiazolidinone analogs as potent in vitro anti-urease agents.

Science.gov (United States)

Rahim, Fazal; Zaman, Khalid; Ullah, Hayat; Taha, Muhammad; Wadood, Abdul; Javed, Muhammad Tariq; Rehman, Wajid; Ashraf, Muhammad; Uddin, Reaz; Uddin, Imad; Asghar, Humna; Khan, Aftab Ahmad; Khan, Khalid M

2015-12-01

4-Thiazolidinone analogs 1-20 were synthesized, characterized by (1)H NMR and EI-MS and investigated for urease inhibitory activity. All twenty (20) analogs exhibited varied degree of urease inhibitory potential with IC50 values 1.73-69.65μM, if compared with standard thiourea having IC50 value of 21.25±0.15μM. Among the series, eight derivatives 3, 6, 8, 10, 15, 17, 19, and 20 showed outstanding urease inhibitory potential with IC50 values of 9.34±0.02, 14.62±0.03, 8.43±0.01, 7.3±0.04, 2.31±0.002, 5.75±0.003, 8.81±0.005, and 1.73±0.001μM, respectively, which is better than the standard thiourea. The remaining analogs showed good to excellent urease inhibition. The binding interactions of these compounds were confirmed through molecular docking studies. Copyright © 2015 Elsevier Inc. All rights reserved.

Andrographolide sodium bisulphite-induced inactivation of urease: inhibitory potency, kinetics and mechanism.

Science.gov (United States)

Mo, Zhi-Zhun; Wang, Xiu-Fen; Zhang, Xie; Su, Ji-Yan; Chen, Hai-Ming; Liu, Yu-Hong; Zhang, Zhen-Biao; Xie, Jian-Hui; Su, Zi-Ren

2015-07-16

The inhibitory effect of andrographolide sodium bisulphite (ASB) on jack bean urease (JBU) and Helicobacter pylori urease (HPU) was performed to elucidate the inhibitory potency, kinetics and mechanism of inhibition in 20 mM phosphate buffer, pH 7.0, 2 mM EDTA, 25 °C. The ammonia formations, indicator of urease activity, were examined using modified spectrophotometric Berthelot (phenol-hypochlorite) method. The inhibitory effect of ASB was characterized with IC50 values. Lineweaver-Burk and Dixon plots for JBU inhibition of ASB was constructed from the kinetic data. SH-blocking reagents and competitive active site Ni2+ binding inhibitors were employed for mechanism study. Molecular docking technique was used to provide some information on binding conformations as well as confirm the inhibition mode. The IC50 of ASB against JBU and HPU was 3.28±0.13 mM and 3.17±0.34 mM, respectively. The inhibition proved to be competitive and concentration- dependent in a slow-binding progress. The rapid formation of initial ASB-JBU complex with an inhibition constant of Ki=2.86×10(-3) mM was followed by a slow isomerization into the final complex with an overall inhibition constant of Ki*=1.33×10(-4) mM. The protective experiment proved that the urease active site is involved in the binding of ASB. Thiol reagents (L-cysteine and dithiothreithol) strongly protect the enzyme from the loss of enzymatic activity, while boric acid and fluoride show weaker protection, indicating that the active-site sulfhydryl group of JBU was potentially involved in the blocking process. Moreover, inhibition of ASB proved to be reversible since ASB-inactivated JBU could be reactivated by dithiothreitol application. Molecular docking assay suggested that ASB made contacts with the important sulfhydryl group Cys-592 residue and restricted the mobility of the active-site flap. ASB was a competitive inhibitor targeting thiol groups of urease in a slow-binding manner both reversibly and concentration

Conformational change results in loss of enzymatic activity of jack bean urease on its interaction with silver nanoparticle.

Science.gov (United States)

Ponnuvel, Shobana; Subramanian, Balakumar; Ponnuraj, Karthe

2015-10-01

Urease is an enzyme produced by microbes such as bacteria, yeast and fungi. Plants also produce this enzyme. Urease action splits urea into ammonia and carbamate. This action is having important implications in agro-chemical, medicinal and environment. Therefore there is always a constant search for new and novel compounds which could inhibit this enzyme. Here we have studied the interaction of jack bean urease (JBU) with silver nanoparticle to analyze the influence of the resultant protein corona formation on the catalytic property of JBU. Several techniques like UV-Vis, gel shift assay and CD spectroscopy have been used to characterize this interaction. Urease activity assay suggests that the protein corona formation inhibits the enzymatic action of JBU. The loss of enzymatic action could be either due to the nanoparticle blocking the active site of JBU or a conformational change in the protein. The CD spectra of JBU-AgNP complexes clearly revealed significant changes in the secondary structural composition of the JBU and this could be the reason for the loss of enzymatic activity of JBU. This study revealed an interesting observation, where the interaction of AgNP with JBU resulted destabilization of hexameric nature of JBU which is otherwise highly stable. The results of the present study could be useful in the development of nanoparticle based material for inhibiting the ureolytic activity of ureases in different fields.

Biological Evaluation and Molecular Docking of Protocatechuic Acid from Hibiscus sabdariffa L. as a Potent Urease Inhibitor by an ESI-MS Based Method.

Science.gov (United States)

Hassan, Sherif T S; Švajdlenka, Emil

2017-10-11

Studies on enzyme inhibition remain a crucial area in drug discovery since these studies have led to the discoveries of new lead compounds useful in the treatment of several diseases. In this study, protocatechuic acid (PCA), an active compound from Hibiscus sabdariffa L. has been evaluated for its inhibitory properties against jack bean urease (JBU) as well as its possible toxic effect on human gastric epithelial cells (GES-1). Anti-urease activity was evaluated by an Electrospray Ionization-Mass Spectrometry (ESI-MS) based method, while cytotoxicity was assayed by the MTT method. PCA exerted notable anti-JBU activity compared with that of acetohydroxamic acid (AHA), with IC 50 values of 1.7 and 3.2 µM, respectively. PCA did not show any significant cytotoxic effect on (GES-1) cells at concentrations ranging from 1.12 to 3.12 µM. Molecular docking study revealed high spontaneous binding ability of PCA to the active site of urease. Additionally, the anti-urease activity was found to be related to the presence of hydroxyl moieties of PCA. This study presents PCA as a natural urease inhibitor, which could be used safely in the treatment of diseases caused by urease-producing bacteria.

Large Scale Screening of Commonly Used Iranian Traditional Medicinal Plants against Urease Activity

Directory of Open Access Journals (Sweden)

Farzaneh Nabati

2012-10-01

Full Text Available Background and purpose of the study:H. pylori infection is an important etiologic impetus usually leading to gastric disease andurease enzyme is the most crucial role is to protect the bacteria in the acidic environment of the stomach. Then urease inhibitors would increase sensitivity of the bacteria in acidic medium.Methods:137 Iranian traditional medicinal plants were examined against Jack bean urease activity by Berthelot reaction. Each herb was extracted using 50% aqueous methanol. The more effectiveextracts were further tested and their IC50 values were determined.Results:37 plants out of the 137 crude extracts revealed strong urease inhibitory activity (more than 70% inhibition against urease activity at 10 mg/ml concentration. Nine of the whole studiedplants crude extracts were found as the most effective with IC50 values less than 500 μg/ml including; Rheum ribes, Sambucus ebulus, Pistachia lentiscus, Myrtus communis, Areca catechu, Citrus aurantifolia, Myristica fragrans, Cinnamomum zeylanicum and Nicotianatabacum.Conclusions:The most potent urease inhibitory was observed for Sambucus ebulus and Rheum ribes extracts with IC50 values of 57 and 92 μg/ml, respectively.

Nanohybrid-layered double hydroxides/urease materials: Synthesis and application to urea biosensors

International Nuclear Information System (INIS)

Vial, S.; Forano, C.; Shan, D.; Mousty, C.; Barhoumi, H.; Martelet, C.; Jaffrezic, N.

2006-01-01

Nanohybrid [ZnAl]-layered double hydroxides/urease were prepared for the first time using the coprecipitation of enzyme and inorganic matrix. By varying the respective amount of urease and LDH, we obtained hybrid materials with various amount and dispersion rate of active biomolecules. X-ray diffraction and infrared spectroscopy confirm the preservation of the structure of each partner while the morphology properties are in good agreement with the permeability study. These new nanohybrids were applied for the development of urea biosensors. Biosensor responses to urea additions were obtained using capacitance (C vs. V) measurements at urease-LDH biofilm deposited on an insulated semiconductor (IS) structure

NikR mediates nickel-responsive transcriptional induction of urease expression in Helicobacter pylori

NARCIS (Netherlands)

A.H.M. van Vliet (Arnoud); S.W. Poppelaars (Sophie); B.J. Davies; J. Stoof (Jeroen); S. Bereswill (Stefan); M. Kist (Manfred); C.W. Penn (Charles); E.J. Kuipers (Ernst); J.G. Kusters (Johannes)

2002-01-01

textabstractThe important human pathogen Helicobacter pylori requires the abundant expression and activity of its urease enzyme for colonization of the gastric mucosa. The transcription, expression, and activity of H. pylori urease were previously demonstrated to be induced by

Kinetic and structural studies reveal a unique binding mode of sulfite to the nickel center in urease.

Science.gov (United States)

Mazzei, Luca; Cianci, Michele; Benini, Stefano; Bertini, Leonardo; Musiani, Francesco; Ciurli, Stefano

2016-01-01

Urease is the most efficient enzyme known to date, and catalyzes the hydrolysis of urea using two Ni(II) ions in the active site. Urease is a virulence factor in several human pathogens, while causing severe environmental and agronomic problems. Sporosarcina pasteurii urease has been used extensively in the structural characterization of the enzyme. Sodium sulfite has been widely used as a preservative in urease solutions to prevent oxygen-induced oxidation, but its role as an inhibitor has also been suggested. In the present study, isothermal titration microcalorimetry was used to establish sulfite as a competitive inhibitor for S. pasteurii urease, with an inhibition constant of 0.19mM at pH7. The structure of the urease-sulfite complex, determined at 1.65Å resolution, shows the inhibitor bound to the dinuclear Ni(II) center of urease in a tridentate mode involving bonds between the two Ni(II) ions in the active site and all three oxygen atoms of the inhibitor, supporting the observed competitive inhibition kinetics. This coordination mode of sulfite has never been observed, either in proteins or in small molecule complexes, and could inspire synthetic coordination chemists as well as biochemists to develop urease inhibitors based on this chemical moiety. Copyright © 2015 Elsevier Inc. All rights reserved.

Meta-analysis of the effect of urease and nitrification inhibitors on crop productivity and nitrogen use efficience

NARCIS (Netherlands)

Abalos, D.; Jeffery, S.L.; Sanz-Cobena, A.; Guardia, G.; Vallejo, A.

2014-01-01

Nitrification and urease inhibitors are proposed as means to reduce nitrogen losses, thereby increasing crop nitrogen use efficiency (NUE). However, their effect on crop yield is variable. A meta-analysis was conducted to evaluate their effectiveness at increasing NUE and crop productivity. Commonly

Streptococcus thermophilus urease activity boosts Lactobacillus delbrueckii subsp. bulgaricus homolactic fermentation.

Science.gov (United States)

Arioli, Stefania; Della Scala, Giulia; Remagni, Maria Chiara; Stuknyte, Milda; Colombo, Stefano; Guglielmetti, Simone; De Noni, Ivano; Ragg, Enzio; Mora, Diego

2017-04-17

The proto-cooperation between Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus in the yogurt consortium enhances the growth rate and size of each population. In contrast, the independent growth of the two species in milk leads to a slower growth rate and a smaller population size. In this study, we report the first evidence that the urease activity of S. thermophilus increases the intracellular pH of L. delbrueckii in the absence of carbon source. However, in milk, in the presence of lactose the alkalizing effect of urea-derived ammonia was not detectable. Nevertheless, based on glucose consumption and lactic acid production at different pH in , L. delbrueckii showed an optimum of glycolysis and homolactic fermentation at alkaline pH values. In milk, we observed that ammonia provided by urea hydrolysis boosted lactic acid production in S. thermophilus and in L. delbrueckii when the species were grown alone or in combination. Therefore, we propose that urease activity acts as an altruistic cooperative trait, which is costly for urease-positive individuals but provides a local benefit because other individuals can take advantage of urease-dependent ammonia release. Copyright © 2016 Elsevier B.V. All rights reserved.

Urease activity in dental plaque and saliva of children during a three-year study period and its relationship with other caries risk factors

Science.gov (United States)

Morou-Bermudez, E; Elias-Boneta, A; Billings, RJ; Burne, RA; Garcia-Rivas, V; Brignoni-Nazario, V; Suarez-Perez, E

2011-01-01

Bacterial urease activity in dental plaque and in saliva generates ammonia, which can increase the plaque pH and can protect acid-sensitive oral bacteria. Recent cross-sectional studies suggest that reduced ability to generate ammonia from urea in dental plaque can be an important caries risk factor. In spite of this proposed important clinical role, there is currently no information available regarding important clinical aspects of oral ureolysis in children. OBJECTIVE The objective of this study was to evaluate the distribution and pattern of urease activity in the dental plaque and in the saliva of children during a three-year period, and to examine the relationship of urease with some important caries risk factors. METHODS A longitudinal study was conducted with repeated measures over a three-year period on a panel of 80 children, ages three to six years at recruitment. The dynamics of change in urease activity were described and associated with clinical, biological, and behavioral caries risk factors. RESULTS Urease activity in plaque showed a trend to remain stable during the study period and was negatively associated with sugar consumption (PUrease activity in unstimulated saliva increased with age, and it was positively associated with the levels of mutans streptococci in saliva and with the educational level of the parents (Purease activity and some important caries risk factors. Urease activity in saliva could be an indicator of mutans infection in children. PMID:21616477

Stabilization of 5A1 urease by covalent attachement to wool | Ahmed ...

African Journals Online (AJOL)

The investigation of five bacterial strains for urease production referred that Bacillus licheniformis 5A1 had the highest urease activity (10.3U/ml/min) after 24h. The enzyme was covalently coupled to different carriers via glutaraldehyde, and wool gave the highest immobilization yield (76.4%) and retained 85% of the original ...

Urea biosensor based on Zn3Al-Urease layered double hydroxides nanohybrid coated on insulated silicon structures

International Nuclear Information System (INIS)

Barhoumi, H.; Maaref, A.; Rammah, M.; Martelet, C.; Jaffrezic, N.; Mousty, C.; Vial, S.; Forano, C.

2006-01-01

Urea biosensors for medical diagnostic monitoring were developed based on the immobilization of urease within layered double hydroxides (LDH). The urease-LDH material was obtained by a stepwise exchange reaction by urease of a Zn 3 Al-dodecyl sulphate (ZnAl-DS) colloidal suspension. XR diffraction and FTIR analysis show that this method gives rise to a Zn 3 Al-Urease LDH nanohybrid material with urease dispersion and textural properties. An aqueous suspension of this urease-LDH nanohybrid material was deposited on an insulated semiconductor (IS) structure. Biosensor responses to urea additions were obtained using capacitance (C vs. V) and impedance (Z vs. ω) measurements. An enhanced maximum limit of the dynamic range was observed in the case of the impedance measurements (110 mM) compared to (5.6 mM) the capacitive urea biosensor. The Michaelis-Menten constant was also calculated according to the Lineweaver-Burk plot. It was found that the K m value with immobilized enzymes was lower (K m = 0.67 mM) in comparison with free enzymes. This K m value obtained from the capacitance measurements indicates that the urea degradation is performed within any inhibition action on the IS/Zn 3 Al-Urease LDH electrode. A comparative study was carried out between these results and those obtained previously, using urease/ZnAl-Cl layered double hydroxides mixture coated on the pH-ISFET transducer

Urease and serine protease inhibitory alkaloids from Isatis tinctoria.

Science.gov (United States)

Ahmad, Ijaz; Fatima, Itrat; Afza, Nighat; Malik, Abdul; Lodhi, Muhammad Arif; Choudhary, Muhammad Iqbal

2008-12-01

Phytochemical investigations on the alkaloidal fraction of the whole plant of the Isatis tinctoria led to the isolation of the alkaloids 1-6., 3'-Hydroxyepiglucoisatisin (3), Epiglucoisatisin (2) were found to be potent urease inhibitors in a concentration-dependent manner with IC(50) values 25.63 +/- 0.74, 37.01 +/- 0.41 and 31.72 +/- 0.93, 47.33 +/- 0.31 microM against Bacillus pasteurii & Jack bean urease, respectively. Compounds 3 and 2 also showed potent inhibitory potential against alpha-chymotrypsin with IC(50) values of 23.40 +/- 0.21 and 27.45 +/- 0.23 microM, respectively.

Fast and sensitive detection of foodborne pathogen using electrochemical impedance analysis, urease catalysis and microfluidics.

Science.gov (United States)

Chen, Qi; Wang, Dan; Cai, Gaozhe; Xiong, Yonghua; Li, Yuntao; Wang, Maohua; Huo, Huiling; Lin, Jianhan

2016-12-15

Early screening of pathogenic bacteria is a key to prevent and control of foodborne diseases. In this study, we developed a fast and sensitive bacteria detection method integrating electrochemical impedance analysis, urease catalysis with microfluidics and using Listeria as model. The Listeria cells, the anti-Listeria monoclonal antibodies modified magnetic nanoparticles (MNPs), and the anti-Listeria polyclonal antibodies and urease modified gold nanoparticles (AuNPs) were incubated in a fluidic separation chip with active mixing to form the MNP-Listeria-AuNP-urease sandwich complexes. The complexes were captured in the separation chip by applying a high gradient magnetic field, and the urea was injected to resuspend the complexes and hydrolyzed under the catalysis of the urease on the complexes into ammonium ions and carbonate ions, which were transported into a microfluidic detection chip with an interdigitated microelectrode for impedance measurement to determine the amount of the Listeria cells. The capture efficiency of the Listeria cells in the separation chip was ∼93% with a shorter time of 30min due to the faster immuno-reaction using the active magnetic mixing. The changes on both impedance magnitude and phase angle were demonstrated to be able to detect the Listeria cells as low as 1.6×10(2)CFU/mL. The detection time was reduced from original ∼2h to current ∼1h. The recoveries of the spiked lettuce samples ranged from 82.1% to 89.6%, indicating the applicability of this proposed biosensor. This microfluidic impedance biosensor has shown the potential for online, automatic and sensitive bacteria separation and detection. Copyright © 2016 Elsevier B.V. All rights reserved.

Agronomic performance of rice to the use of urease inhibitor in two cropping systems Desempenho agronômico do arroz irrigado ao uso de inibidor de urease em dois sistemas de cultivo

Directory of Open Access Journals (Sweden)

Enio Marchesan

2013-09-01

Full Text Available The use of urea coated with urease inhibitor may become a useful tool for increasing the efficiency of nitrogen top-dressing in rice crop, thereby reducing nutrient losses through volatilization of NH3 (ammonia. Thus, the aim of this study was to evaluate the volatilization of NH3 and the response of rice to the use of urea coated with urease inhibitor in two cropping systems, no-tillage and conventional. For this purpose, field experiments were developed in the agricultural years 2007/2008 and 2008/2009, in UFSM in Santa Maria-RS. The design was randomized blocks in bifactorial scheme (2x5 with two sources, urea and urea + NBPT and five intervals of water intake (0; 3; 6; 9; 12 days after application of nitrogen sources. The results of two seasons show that the urease inhibitor present in urea slows and decrease the conversion of N to NH3, reducing the losses by volatilization, compared to urea without inhibitor. Among the systems, the losses are magnified in the no-tillage cropping system. The behavior of the response variable in relation to productivity is variable in two cropping systems used in this study and the stress caused to the rice plant by the late start of the irrigation is more damaging than the losses caused by the volatilization of NH3.A utilização de uréia recoberta com inibidor de urease pode tornar-se uma ferramenta útil para aumentar a eficiência da adubação nitrogenada em cobertura na cultura do arroz irrigado, diminuindo assim perdas do nutriente por volatilização de NH3 (amônia. Com isso, o objetivo desse trabalho foi avaliar a volatilização de NH3 e a resposta do arroz irrigado ao uso de uréia recoberta com inibidor de urease em dois sistemas de cultivo, direto e convencional. Para tanto, conduziram-se experimentos em campo, nos anos agrícolas 2007/2008 e 2008/2009, na UFSM em Santa Maria-RS. O delineamento utilizado foi o delineamento experimental blocos completos casualizados em esquema bifatorial (2x5

Biological Evaluation and Molecular Docking of Protocatechuic Acid from Hibiscus sabdariffa L. as a Potent Urease Inhibitor by an ESI-MS Based Method

Directory of Open Access Journals (Sweden)

Sherif T. S. Hassan

2017-10-01

Full Text Available Studies on enzyme inhibition remain a crucial area in drug discovery since these studies have led to the discoveries of new lead compounds useful in the treatment of several diseases. In this study, protocatechuic acid (PCA, an active compound from Hibiscus sabdariffa L. has been evaluated for its inhibitory properties against jack bean urease (JBU as well as its possible toxic effect on human gastric epithelial cells (GES-1. Anti-urease activity was evaluated by an Electrospray Ionization-Mass Spectrometry (ESI-MS based method, while cytotoxicity was assayed by the MTT method. PCA exerted notable anti-JBU activity compared with that of acetohydroxamic acid (AHA, with IC50 values of 1.7 and 3.2 µM, respectively. PCA did not show any significant cytotoxic effect on (GES-1 cells at concentrations ranging from 1.12 to 3.12 µM. Molecular docking study revealed high spontaneous binding ability of PCA to the active site of urease. Additionally, the anti-urease activity was found to be related to the presence of hydroxyl moieties of PCA. This study presents PCA as a natural urease inhibitor, which could be used safely in the treatment of diseases caused by urease-producing bacteria.

Inactivation of Phaeodactylum tricornutum urease gene using transcription activator-like effector nuclease-based targeted mutagenesis.

Science.gov (United States)

Weyman, Philip D; Beeri, Karen; Lefebvre, Stephane C; Rivera, Josefa; McCarthy, James K; Heuberger, Adam L; Peers, Graham; Allen, Andrew E; Dupont, Christopher L

2015-05-01

Diatoms are unicellular photosynthetic algae with promise for green production of fuels and other chemicals. Recent genome-editing techniques have greatly improved the potential of many eukaryotic genetic systems, including diatoms, to enable knowledge-based studies and bioengineering. Using a new technique, transcription activator-like effector nucleases (TALENs), the gene encoding the urease enzyme in the model diatom, Phaeodactylum tricornutum, was targeted for interruption. The knockout cassette was identified within the urease gene by PCR and Southern blot analyses of genomic DNA. The lack of urease protein was confirmed by Western blot analyses in mutant cell lines that were unable to grow on urea as the sole nitrogen source. Untargeted metabolomic analysis revealed a build-up of urea, arginine and ornithine in the urease knockout lines. All three intermediate metabolites are upstream of the urease reaction within the urea cycle, suggesting a disruption of the cycle despite urea production. Numerous high carbon metabolites were enriched in the mutant, implying a breakdown of cellular C and N repartitioning. The presented method improves the molecular toolkit for diatoms and clarifies the role of urease in the urea cycle. © 2014 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

A phylogenetic comparison of urease-positive thermophilic Campylobacter (UPTC) and urease-negative (UN) C. lari.

Science.gov (United States)

Hirayama, Junichi; Tazumi, Akihiro; Hayashi, Kyohei; Tasaki, Erina; Kuribayashi, Takashi; Moore, John E; Millar, Beverley C; Matsuda, Motoo

2011-06-01

In the present study, the reliability of full-length gene sequence information for several genes including 16S rRNA was examined, for the discrimination of the two representative Campylobacter lari taxa, namely urease-negative (UN) C. lari and urease-positive thermophilic Campylobacter (UPTC). As previously described, 16S rRNA gene sequence are not reliable for the molecular discrimination of UN C. lari from UPTC organisms employing both the unweighted pair group method using arithmetic means analysis (UPGMA) and neighbor joining (NJ) methods. In addition, three composite full-length gene sequences (ciaB, flaC and vacJ) out of seven gene loci examined were reliable for discrimination employing dendrograms constructed by the UPGMA method. In addition, all the dendrograms of the NJ phylogenetic trees constructed based on the nine gene information were not reliable for the discrimination. Three composite full-length gene sequences (ciaB, flaC and vacJ) were reliable for the molecular discrimination between UN C. lari and UPTC organisms employing the UPGMA method, as well as among four thermophilic Campylobacter species. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Structural Basis of Binding and Rationale for the Potent Urease Inhibitory Activity of Biscoumarins

Science.gov (United States)

Lodhi, Muhammad Arif; Choudhary, Muhammad Iqbal; Lodhi, Atif; Ul-Haq, Zaheer; Jalil, Saima; Nawaz, Sarfraz Ahmad; Khan, Khalid Mohammed; Iqbal, Sajid; Rahman, Atta-ur

2014-01-01

Urease belongs to a family of highly conserved urea-hydrolyzing enzymes. A common feature of these enzymes is the presence of two Lewis acid nickel ions and reactive cysteine residue in the active sites. In the current study we examined a series of biscoumarins 1–10 for their mechanisms of inhibition with the nickel containing active sites of Jack bean and Bacillus pasteurii ureases. All these compounds competitively inhibited Jack bean urease through interaction with the nickel metallocentre, as deduced from Michaelis-Menten kinetics, UV-visible absorbance spectroscopic, and molecular docking simulation studies. Some of the compounds behaved differently in case of Bacillus pasteurii urease. We conducted the enzyme kinetics, UV-visible spectroscopy, and molecular docking results in terms of the known protein structure of the enzyme. We also evaluated possible molecular interpretations for the site of biscoumarins binding and found that phenyl ring is the major active pharmacophore. The excellent in vitro potency and selectivity profile of the several compounds described combined with their nontoxicity against the human cells and plants suggest that these compounds may represent a viable lead series for the treatment of urease associated problems. PMID:25295281

Effect of low concentrations of ozone on the enzymes catalase, peroxidase, papain and urease

Energy Technology Data Exchange (ETDEWEB)

Todd, G W

1958-01-01

The enzymes catalase, peroxidase, papain and urease were treated in vitro with low concentrations of ozone gas. Wide variations were found in the sensitivity of the enzymes to the inhibitory action of the gas. Papain showed the greatest sensitivity; the rest required a much greater amount of ozone for inactivation. Comparisons of ozone and hydrogen peroxide as inhibitors of papain and urease showed ozone to be 30 times as effective as hydrogen peroxide on papain and 3 times as effective on urease. 14 references, 2 figures, 3 tables.

Rapid presumptive identification of the Mycobacterium tuberculosis-bovis complex by radiometric determination of heat stable urease

International Nuclear Information System (INIS)

Gandy, J.H.; Pruden, E.L.; Cox, F.R.

1983-01-01

Simple and rapid Bactec methodologies for the determination of neat (unaltered) and heat stable urease activity of mycobacteria are presented. Clinical isolates (63) and stock cultures (32)--consisting of: M. tuberculosis (19), M. bovis (5), M. kansasii (15), M. marinum (4), M. simiae (3), M. scrofulaceum (16), M. gordonae (6), M. szulgai (6), M. flavescens (1), M. gastri (1), M. intracellulare (6), M. fortuitum-chelonei complex (12), and M. smegmatis (1)--were tested for neat urease activity by Bactec radiometry. Mycobacterial isolates (50-100 mg wet weight) were incubated at 35 degrees C for 30 minutes with microCi14C-urea. Urease-positive mycobacteria gave Bactec growth index (GI) values greater than 100 units, whereas urease-negative species gave values less than 10 GI units. Eighty-three isolates possessing neat urease activity were heated at 80 degrees C for 30 minutes followed by incubation at 35 degrees C for 30 minutes with 1 microCi14C-urea. Mycobacterium tuberculosis-bovis complex demonstrated heat-stable urease activity (GI more than 130 units) and could be distinguished from mycobacteria other than tuberculosis (MOTT), which gave GI values equal to or less than 40 units

pH-dependent immobilization of urease on glutathione-capped gold nanoparticles.

Science.gov (United States)

Garg, Seema; De, Arnab; Mozumdar, Subho

2015-05-01

Urease is a nickel-dependent metalloenzyme that catalyzes the hydrolysis of urea to form ammonia and carbon dioxide. Although the enzyme serves a significant role in several detoxification and analytical processes, its usability is restricted due to high cost, availability in small amounts, instability, and a limited possibility of economic recovery from a reaction mixture. Hence, there is a need to develop an efficient, simple, and reliable immobilization strategy for the enzyme. In this study, the carboxyl terminated surface of glutathione-capped gold nanoparticles have been utilized as a solid support for the covalent attachment of urease. The immobilization has been carried out at different pH conditions so as to elucidate its effect on the immobilization efficiency and enzyme bioactivity. The binding of the enzyme has been quantitatively and qualitatively analyzed through techniques like ultraviolet-visible spectroscopy, intrinsic steady state fluorescence, and circular dichorism. The bioactivity of the immobilized enzyme was investigated with respect to the native enzyme under different thermal conditions. Recyclability and shelf life studies of the immobilized enzyme have also been carried out. Results reveal that the immobilization is most effective at pH of 7.4 followed by that in an acidic medium and is least in alkaline environment. The immobilized enzyme also exhibits enhance activity in comparison to the native form at physiological temperature. The immobilized urease (on gold glutathione nanoconjugates surface) can be effectively employed for biosensor fabrication, immunoassays and as an in vivo diagnostic tool in the future. © 2014 Wiley Periodicals, Inc.

1,2-Benzisoselenazol-3(2H)-one Derivatives As a New Class of Bacterial Urease Inhibitors.

Science.gov (United States)

Macegoniuk, Katarzyna; Grela, Ewa; Palus, Jerzy; Rudzińska-Szostak, Ewa; Grabowiecka, Agnieszka; Biernat, Monika; Berlicki, Łukasz

2016-09-08

Urease inhibitors are considered promising compounds for the treatment of ureolytic bacterial infections, particularly infections resulting from Helicobacter pylori in the gastric tract. Herein, we present the synthesis and the inhibitory activity of novel and highly effective organoselenium compounds as inhibitors of Sporosarcina pasteurii and Helicobacter pylori ureases. These studied compounds represent a class of competitive reversible urease inhibitors. The most active compound, 2-phenyl-1,2-benzisoselenazol-3(2H)-one (ebselen), displayed Ki values equal to 2.11 and 226 nM against S. pasteurii and H. pylori enzymes, respectively, indicating ebselen as one of the most potent low-molecular-weight inhibitors of bacterial ureases reported to date. Most of these molecules penetrated through the cell membrane of the Gram-negative bacteria Escherichia coli (pGEM::ureOP) in vitro. Furthermore, whole-cell studies on the H. pylori J99 reference strain confirmed the high efficiency of the examined organoselenium compounds as urease inhibitors against pathogenic bacteria.

Mutational analysis of the major soybean UreF paralogue involved in urease activation

Science.gov (United States)

In soybean, mutation at Eu2 or Eu3 eliminates the urease activities of both the embryo-specific and the tissue-ubiquitous (assimilatory) isozymes, encoded by Eu1 and Eu4, respectively. Eu3 encodes UreG, a GTP’ase necessary for proper emplacement of Ni and carbon dioxide in the urease active site. ...

HOMOLOGY MODELING AND MOLECULAR DYNAMICS STUDY OF MYCOBACTERIUM TUBERCULOSIS UREASE

Directory of Open Access Journals (Sweden)

Lisnyak Yu. V.

2017-10-01

Full Text Available Introduction. M. tuberculosis urease (MTU is an attractive target for chemotherapeutic intervention in tuberculosis by designing new safe and efficient enzyme inhibitors. A prerequisite for designing such inhibitors is an understanding of urease's three-dimensional (3D structure organization. 3D structure of M. tuberculosis urease is unknown. When experimental three-dimensional structure of a protein is not known, homology modeling, the most commonly used computational structure prediction method, is the technique of choice. This paper aimed to build a 3D-structure of M. tuberculosis urease by homology modeling and to study its stability by molecular dynamics simulations. Materials and methods. To build MTU model, five high-resolution X-ray structures of bacterial ureases with three-subunit composition (2KAU, 5G4H, 4UBP, 4СEU, and 4EPB have been selected as templates. For each template five stochastic alignments were created and for each alignment, a three-dimensional model was built. Then, each model was energy minimized and the models were ranked by quality Z-score. The MTU model with highest quality estimation amongst 25 potential models was selected. To further improve structure quality the model was refined by short molecular dynamics simulation that resulted in 20 snapshots which were rated according to their energy and the quality Z-score. The best scoring model having minimum energy was chosen as a final homology model of 3D structure for M. tuberculosis. The final model of MTU was also validated by using PDBsum and QMEAN servers. These checks confirmed good quality of MTU homology model. Results and discussion. Homology model of MTU is a nonamer (homotrimer of heterotrimers, (αβγ3 consisting of 2349 residues. In MTU heterotrimer, sub-units α, β, and γ tightly interact with each other at a surface of approximately 3000 Å2. Sub-unit α contains the enzyme active site with two Ni atoms coordinated by amino acid residues His347, His

CYTOTOXIC, α-CHYMOTRYPSIN AND UREASE INHIBITION ACTIVITIES OF THE PLANT Heliotropium dasycarpum L.

Science.gov (United States)

Ghaffari, Muhammad Abuzar; Chaudhary, Bashir Ahmed; Uzair, Muhammad; Ashfaq, Khuram

2016-01-01

The aim of this study was to investigate Cytotoxic, α-Chymotrypsin and Urease inhibition activities of the plant Heliotropium dasycarpum . Dichloromethane and methanol extracts of the plant were evaluated for cytotoxic, α-Chymotrypsin and Urease inhibition by using in vivo Brine Shrimp lethality bioassay and in vitro enzymatic inhibition assays respectively. The methanol extract of the plant exhibited significant cytotoxic activity. Out of 30 brine shrimp larvae, 2 (6%), 26 (86%) and 28 (93%) larvae were survived at concentration of 1000μg/ml, 100μg/ml and 10μg/ml respectively with LD50; 215.837. Similarly 21 (70%), 25 (83%), 29 (96%) larvae were survived of dichloromethane plant extract with LD50; 6170.64. The methanol and dichloromethane extract exhibited 10.50±0.18% and 41.51±0.15% α-chymotrypsin enzyme inhibition respectively with IC 50 values of greater than 500 μmol. The methanol extract showed 24.39±0.21% Urease enzyme inhibition with IC 50 values of greater than 400 μmol While dichloromethane extract has 11.46±0.09% enzyme inhibition with IC 50 values of greater than 500 μmol. The results clearly indicated that Heliotropium dasycarpum has cytotoxic potential and enzyme inhibition properties. Further study is needed to screen out antitumor and anti-ulcerative agents.

Three-component synthesis of pyrano[2,3-d]-pyrimidine dione derivatives facilitated by sulfonic acid nanoporous silica (SBA-Pr-SO3H and their docking and urease inhibitory activity

Directory of Open Access Journals (Sweden)

Ghodsi Mohammadi Ziarani

2013-01-01

Full Text Available A straightforward and efficient method for the synthesis of pyrano[2,3-d]pyrimidine diones derivatives from the reaction of barbituric acid, malononitrile and various aromatic aldehydes using SBA-Pr-SO3H as a nanocatalyst is reported.ResultsReactions proceed with high efficiency under solvent free conditions. Urease inhibitory activity of pyrano[2,3-d]pyrimidine diones derivatives were tested against Jack bean urease using phenol red method. Three compounds of 4a, 4d and 4l were not active in urease inhibition test, but compound 4a displayed slight urease activation properties. Compounds 4b, 4k, 4f, 4e, 4j, 4g and 4c with hydrophobic substitutes on phenyl ring, showed good inhibitory activity (19.45-279.14 muM.DiscussionThe compounds with electron donating group and higher hydrophobic interaction with active site of enzyme prevents hydrolysis of substrate. Electron withdrawing groups such as nitro at different position and meta-methoxy reduced urease inhibitory activity. Substitution of both hydrogen of barbituric acid with methyl group will convert inhibitor to activator.

Three-component synthesis of pyrano[2,3-d]-pyrimidine dione derivatives facilitated by sulfonic acid nanoporous silica (SBA-Pr-SO3H and their docking and urease inhibitory activity

Directory of Open Access Journals (Sweden)

Ziarani Ghodsi Mohammadi

2013-01-01

Full Text Available Abstract Background A straightforward and efficient method for the synthesis of pyrano[2,3-d]pyrimidine diones derivatives from the reaction of barbituric acid, malononitrile and various aromatic aldehydes using SBA-Pr-SO3H as a nanocatalyst is reported. Results Reactions proceed with high efficiency under solvent free conditions. Urease inhibitory activity of pyrano[2,3-d]pyrimidine diones derivatives were tested against Jack bean urease using phenol red method. Three compounds of 4a, 4d and 4l were not active in urease inhibition test, but compound 4a displayed slight urease activation properties. Compounds 4b, 4k, 4f, 4e, 4j, 4g and 4c with hydrophobic substitutes on phenyl ring, showed good inhibitory activity (19.45-279.14 μM. Discussion The compounds with electron donating group and higher hydrophobic interaction with active site of enzyme prevents hydrolysis of substrate. Electron withdrawing groups such as nitro at different position and meta-methoxy reduced urease inhibitory activity. Substitution of both hydrogen of barbituric acid with methyl group will convert inhibitor to activator.

Distribution of the urease gene cluster among and urease activities of enterohemorrhagic Escherichia coli O157 isolates from humans

NARCIS (Netherlands)

Friedrich, Alexander W; Köck, Robin; Bielaszewska, Martina; Zhang, Wenlan; Karch, Helge; Mathys, Werner

Enterohemorrhagic Escherichia coli (EHEC) O157 strains belong to two closely related major groups, which are differentiated by their sorbitol fermentation phenotypes. Here we studied the conservation of urease genes and their expression in sorbitol-fermenting (SF) and non-SF EHEC O157 isolates. PCR

Urease activity in different soils of Egypt.

Science.gov (United States)

el-Shinnawi, M M

1978-01-01

Samples from two depths (0--15 and 15--30 cm) of five Egyptian soils: sandy, calcareous, fertile alluvial, saline alluvial, and alkali alluvial were tested for urease activity. Samples were treated with farmyard manure at rates of 0 and 0.5% C, and moisture at levels of 50, 65, and 80% of the water holding capacity. The studied Egyptian soils showed different activities of urease. Decreases in the values were shown by depth of sampling and varied in their intensities according to soil type, except for saline soil which revealed an opposite trend by the higher activity of its sub-surface layer. Order of activity was the following: fertile, saline, alkali, calcareous, and sandy soil. Farmyard manure slightly increased the activity of the enzyme. Incubation of moistened samples revealed that the optimum moisture content was 50% of W.H.C. for the tested soils, except for saline which showed best results at 65% of W.H.C.

Urease Inhibition in the Presence of N-(n-Butyl)thiophosphoric Triamide, a Suicide Substrate: Structure and Kinetics.

Science.gov (United States)

Mazzei, Luca; Cianci, Michele; Contaldo, Umberto; Musiani, Francesco; Ciurli, Stefano

2017-10-10

The nickel-dependent enzyme urease is a virulence factor for a large number of pathogenic and antibiotic-resistant bacteria, as well as a negative factor for the efficiency of soil nitrogen fertilization for crop production. The use of urease inhibitors to offset these effects requires knowledge, at a molecular level, of their mode of action. The 1.28 Å resolution structure of the enzyme-inhibitor complex obtained upon incubation of Sporosarcina pasteurii urease with N-(n-butyl)thiophosphoric triamide (NBPT), a molecule largely utilized in agriculture, reveals the presence of the monoamidothiophosphoric acid (MATP) moiety, obtained upon enzymatic hydrolysis of the diamide derivative of NBPT (NBPD) to yield n-butyl amine. MATP is bound to the two Ni(II) ions in the active site of urease using a μ 2 -bridging O atom and terminally bound O and NH 2 groups, with the S atom of the thiophosphoric amide pointing away from the metal center. The mobile flap modulating the size of the active site cavity is found in the closed conformation. Docking calculations suggest that the interaction between urease in the open flap conformation and NBPD involves a role for the conserved αArg339 in capturing and orienting the inhibitor prior to flap closure. Calorimetric and spectrophotometric determinations of the kinetic parameters of this inhibition indicate the occurrence of a reversible slow inhibition mode of action, characterized, for both bacterial and plant ureases, by a very small value of the dissociation constant of the urease-MATP complex. No need to convert NBPT to its oxo derivative NBPTO, as previously proposed, is necessary for urease inhibition.

Inhibition of Helicobacter pylori and Its Associate Urease by Labdane Diterpenoids Isolated from Andrographis paniculata.

Science.gov (United States)

Shaikh, Rafik U; Dawane, Ashwini A; Pawar, Rajendra P; Gond, Dhananjay S; Meshram, Rohan J; Gacche, Rajesh N

2016-03-01

The present study was carried out to evaluate anti-Helicobacter pylori and its associated urease activity of labdane diterpenoids isolated from Andrographis paniculata. A molecular docking analysis was performed by using ArgusLab 4.0.1 software. The results obtained indicate that compound A possesses strong inhibition to H. pylori, 28 ± 2.98 (minimum inhibitory concentration, 9 µg/mL), and its urease, 85.54 ± 2.62% (IC50 , 20.2 µg/mL). Compounds B, C, and D also showed moderate inhibition to H. pylori and its urease. The obtained results were in agreement with the molecular docking analysis of compounds. The phytochemicals under investigation were found to be promising antibacterial agents. Moreover, the isolated compounds can be considered as a resource for searching novel anti-H. pylori agents possessing urease inhibition. Copyright © 2015 John Wiley & Sons, Ltd.

Exogenous application of urea and a urease inhibitor improves drought stress tolerance in maize (Zea mays L.).

Science.gov (United States)

Gou, Wei; Zheng, Pufan; Tian, Li; Gao, Mei; Zhang, Lixin; Akram, Nudrat Aisha; Ashraf, Muhammad

2017-05-01

Drought is believed to cause many metabolic changes which affect plant growth and development. However, it might be mitigated by various inorganic substances, such as nitrogen. Thus, the study was carried out to investigate the effect of foliar-applied urea with or without urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT) on a maize cultivar under drought stress simulated by 15% (w/v) polyethylene glycol 6000. Foliar-applied urea resulted in a significant increase in plant dry weight, relative water content, and photosynthetic pigments under water stress condition. Furthermore, the activities of superoxide dismutase (SOD), peroxidase (POD), and hydrogen peroxidase (CAT), were enhanced with all spraying treatments under drought stress, which led to decreases in accumulation of hydrogen peroxide (H 2 O 2 ), superoxide anion ([Formula: see text]) and malondialdehyde (MDA). The contents of soluble protein and soluble sugar accumulated remarkably with urea-applied under drought stress condition. Moreover, a further enhancement in above metabolites was observed by spraying a mixture of urea and urease inhibitor as compared to urea sprayed only. Taken together, our findings show that foliar application of urea and a urease inhibitor could significantly enhance drought tolerance of maize through protecting photosynthetic apparatus, activating antioxidant defense system and improving osmoregulation.

Synthesis and characterization of a stable humic-urease complex: application to barley seed encapsulation for improving N uptake.

Science.gov (United States)

Mvila, Beaufray G; Pilar-Izquierdo, María C; Busto, María D; Perez-Mateos, Manuel; Ortega, Natividad

2016-07-01

Most N fertilizers added to soil are not efficiently used by plants and are lost to the atmosphere or leached from the soil, causing environmental pollution and increasing cost. Barley seed encapsulation in calcium alginate gels containing free or immobilized urease to enhance plant utilization of soil N was investigated. Urease was immobilized with soil humic acids (HA). A central composite face-centered design was applied to optimize the immobilization process, reaching an immobilization yield of 127%. Soil stability of urease was enhanced after the immobilization. Seed encapsulation with free urease (FU) and humic-urease complex (HUC) resulted in a urease activity retention in the coating layer of 46% and 24%, and in germination rates of 87% and 92%, respectively. Under pot culture conditions, the pots planted with seeds encapsulated with FU and HUC showed higher ammonium N (NH4 (+) -N) (26% and 64%, respectively) than the control soil at 28 days after planting (DAP). Moreover, the seed encapsulation with FU and HUC increased the N uptake 83% and 97%, respectively, at 35 DAP. Seed encapsulation with urease could substantially contribute to enhancing plant N nutrition in the early stages of seedling establishment. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

Bisindolylmethane thiosemicarbazides as potential inhibitors of urease: Synthesis and molecular modeling studies.

Science.gov (United States)

Taha, Muhammad; Ullah, Hayat; Al Muqarrabun, Laode Muhammad Ramadhan; Khan, Muhammad Naseem; Rahim, Fazal; Ahmat, Norizan; Javid, Muhammad Tariq; Ali, Muhammad; Khan, Khalid Mohammed

2018-01-01

Bisindolylmethane thiosemicarbazides 1-18 were synthesized, characterized by 1 H NMR and ESI MS and evaluated for urease inhibitory potential. All analogs showed outstanding urease inhibitory potentials with IC 50 values ranging between 0.14 ± 0.01 to 18.50 ± 0.90 μM when compared with the standard inhibitor thiourea having IC 50 value 21.25 ± 0.90 μM. Among the series, analog 9 (0.14 ± 0.01 μM) with di-chloro substitution on phenyl ring was identified as the most potent inhibitor of urease. The structure activity relationship has been also established on the basis of binding interactions of the active analogs. These binding interactions were identified by molecular docking studies. Copyright © 2017 Elsevier Ltd. All rights reserved.

Spectrometric and Voltammetric Analysis of Urease – Nickel Nanoelectrode as an Electrochemical Sensor

Directory of Open Access Journals (Sweden)

Rene Kizek

2007-07-01

Full Text Available Urease is the enzyme catalyzing the hydrolysis of urea into carbon dioxide andammonia. This enzyme is substrate-specific, which means that the enzyme catalyzes thehydrolysis of urea only. This feature is a basic diagnostic criterion used in thedetermination of many bacteria species. Most of the methods utilized for detection ofurease are based on analysis of its enzyme activity – the hydrolysis of urea. The aim of thiswork was to detect urease indirectly by spectrometric method and directly by voltammetricmethods. As spectrometric method we used is called indophenol assay. The sensitivity ofdetection itself is not sufficient to analyse the samples without pre-concentration steps.Therefore we utilized adsorptive transfer stripping technique coupled with differential pulse voltammetry to detect urease. The influence of accumulation time, pH of supporting electrolyte and concentration of urease on the enzyme peak height was investigated. Under the optimized experimental conditions (0.2 M acetate buffer pH 4.6 and accumulation time of 120 s the detection limit of urease evaluated as 3 S/N was 200 ng/ml. The activity of urease enzyme depends on the presence of nickel. Thus the influence of nickel(II ions on electrochemical response of the enzyme was studied. Based on the results obtained the interaction of nickel(II ions and urease can be determined using electrochemical methods. Therefore we prepared Ni nanoelectrodes to measure urease. The Ni nanoelectrodes was analysed after the template dissolution by scanning electron microscopy. The results shown vertically aligned Ni nanopillars almost covered the electrode surface, whereas the defect places are minor and insignificant in comparison with total electrode surface. We were able to not only detect urease itself but also to distinguish its native and denatured form.

LIGAND-BINDING SITES ON THE MYCOBACTERIUM TUBERCULOSIS UREASE

Directory of Open Access Journals (Sweden)

Lisnyak Yu. V.

2017-10-01

Full Text Available Introduction. Mycobacterium tuberculosis is the causative agent of tuberculosis that remains a serious medical and social health problem. Despite intensive efforts have been made in the past decade, there are no new efficient anti-tuberculosis drugs today, and that need is growing due to the spread of drug-resistant strains of M.tuberculosis. M. tuberculosis urease (MTU, being an important factor of the bacterium viability and virulence, is an attractive target for anti-tuberculosis drugs acting by inhibition of urease activity. However, the commercially available urease inhibitors are toxic and unstable, that prevent their clinical use. Therefore, new more potent anti-tuberculosis drugs inhibiting new targets are urgently needed. A useful tool for the search of novel inhibitors is a computational drug design. The inhibitor design is significantly easier if binding sites on the enzyme are identified in advance. This paper aimed to determine the probable ligand binding sites on the surface of M. tuberculosis urease. Methods. To identify ligand binding sites on MTU surface, сomputational solvent mapping method FTSite was applied by the use of MTU homology model we have built earlier. The method places molecular probes (small organic molecules containing various functional groups on a dense grid defined around the enzyme, and for each probe finds favorable positions. The selected poses are refined by free energy minimization, the low energy conformations are clustered, and the clusters are ranked on the basis of the average free energy. FTSite server outputs the protein residues delineating a binding sites and the probe molecules representing each cluster. To predict allosteric pockets on MTU, AlloPred and AlloSite servers were applied. AlloPred uses the normal mode analysis (NMA and models how the dynamics of a protein would be altered in the presence of a modulator at a specific pocket. Pockets on the enzyme are predicted using the Fpocket

Synthesis, structures and urease inhibitory activity of cobalt(III) complexes with Schiff bases.

Science.gov (United States)

Jing, Changling; Wang, Cunfang; Yan, Kai; Zhao, Kedong; Sheng, Guihua; Qu, Dan; Niu, Fang; Zhu, Hailiang; You, Zhonglu

2016-01-15

A series of new cobalt(III) complexes were prepared. They are [CoL(1)(py)3]·NO3 (1), [CoL(2)(bipy)(N3)]·CH3OH (2), [CoL(3)(HL(3))(N3)]·NO3 (3), and [CoL(4)(MeOH)(N3)] (4), where L(1), L(2), L(3) and L(4) are the deprotonated form of N'-(2-hydroxy-5-methoxybenzylidene)-3-methylbenzohydrazide, N'-(2-hydroxybenzylidene)-3-hydroxylbenzohydrazide, 2-[(2-dimethylaminoethylimino)methyl]-4-methylphenol, and N,N'-bis(5-methylsalicylidene)-o-phenylenediamine, respectively, py is pyridine, and bipy is 2,2'-bipyridine. The complexes were characterized by infrared and UV-Vis spectra, and single crystal X-ray diffraction. The Co atoms in the complexes are in octahedral coordination. Complexes 1 and 4 show effective urease inhibitory activities, with IC50 values of 4.27 and 0.35 μmol L(-1), respectively. Complex 2 has medium activity against urease, with IC50 value of 68.7 μmol L(-1). While complex 3 has no activity against urease. Molecular docking study of the complexes with Helicobacter pylori urease was performed. Copyright © 2015 Elsevier Ltd. All rights reserved.

3-Arylpropionylhydroxamic acid derivatives as Helicobacter pylori urease inhibitors: Synthesis, molecular docking and biological evaluation.

Science.gov (United States)

Shi, Wei-Kang; Deng, Rui-Cheng; Wang, Peng-Fei; Yue, Qin-Qin; Liu, Qi; Ding, Kun-Ling; Yang, Mei-Hui; Zhang, Hong-Yu; Gong, Si-Hua; Deng, Min; Liu, Wen-Run; Feng, Qiu-Ju; Xiao, Zhu-Ping; Zhu, Hai-Liang

2016-10-01

Helicobacter pylori urease is involved in several physiologic responses such as stomach and duodenal ulcers, adenocarcinomas and stomach lymphomas. Thus, inhibition of urease is taken for a good chance to treat H. pylori-caused infections, we have therefore focused our efforts on seeking novel urease inhibitors. Here, a series of arylpropionylhydroxamic acids were synthesized and evaluated for urease inhibition. Out of these compounds, 3-(2-benzyloxy-5-chlorophenyl)-3-hydroxypropionylhydroxamic acid (d24) was the most active inhibitor with IC50 of 0.15±0.05μM, showing a mixed inhibition with both competitive and uncompetitive aspects. Non-linear fitting of kinetic data gives kinetics parameters of 0.13 and 0.12μg·mL(-1) for Ki and Ki', respectively. The plasma protein binding assays suggested that d24 exhibited moderate binding to human and rabbit plasma proteins. Copyright © 2016 Elsevier Ltd. All rights reserved.

Increased incidence of urolithiasis and bacteremia during Proteus mirabilis and Providencia stuartii coinfection due to synergistic induction of urease activity.

Science.gov (United States)

Armbruster, Chelsie E; Smith, Sara N; Yep, Alejandra; Mobley, Harry L T

2014-05-15

Catheter-associated urinary tract infections (CaUTIs) are the most common hospital-acquired infections worldwide and are frequently polymicrobial. The urease-positive species Proteus mirabilis and Providencia stuartii are two of the leading causes of CaUTIs and commonly co-colonize catheters. These species can also cause urolithiasis and bacteremia. However, the impact of coinfection on these complications has never been addressed experimentally. A mouse model of ascending UTI was utilized to determine the impact of coinfection on colonization, urolithiasis, and bacteremia. Mice were infected with P. mirabilis or a urease mutant, P. stuartii, or a combination of these organisms. In vitro experiments were conducted to assess growth dynamics and impact of co-culture on urease activity. Coinfection resulted in a bacterial load similar to monospecies infection but with increased incidence of urolithiasis and bacteremia. These complications were urease-dependent as they were not observed during coinfection with a P. mirabilis urease mutant. Furthermore, total urease activity was increased during co-culture. We conclude that P. mirabilis and P. stuartii coinfection promotes urolithiasis and bacteremia in a urease-dependent manner, at least in part through synergistic induction of urease activity. These data provide a possible explanation for the high incidence of bacteremia resulting from polymicrobial CaUTI.

Kinetics and mechanism of jack bean urease inhibition by Hg2+

Directory of Open Access Journals (Sweden)

Du Nana

2012-12-01

Full Text Available Abstract Background Jack bean urease (EC 3.5.1.5 is a metalloenzyme, which catalyzes the hydrolysis of urea to produce ammonia and carbon dioxide. The heavy metal ions are common inhibitors to control the rate of the enzymatic urea hydrolysis, which take the Hg2+ as the representative. Hg2+ affects the enzyme activity causing loss of the biological function of the enzyme, which threatens the survival of many microorganism and plants. However, inhibitory kinetics of urease by the low concentration Hg2+ has not been explored fully. In this study, the inhibitory effect of the low concentration Hg2+ on jack bean urease was investigated in order to elucidate the mechanism of Hg2+ inhibition. Results According to the kinetic parameters for the enzyme obtained from Lineweaver–Burk plot, it is shown that the Km is equal to 4.6±0.3 mM and Vm is equal to 29.8±1.7 μmol NH3/min mg. The results show that the inhibition of jack bean urease by Hg2+ at low concentration is a reversible reaction. Equilibrium constants have been determined for Hg2+ binding with the enzyme or the enzyme-substrate complexes (Ki =0.012 μM. The results show that the Hg2+ is a noncompetitive inhibitor. In addition, the kinetics of enzyme inhibition by the low concentration Hg2+ has been studied using the kinetic method of the substrate reaction. The results suggest that the enzyme first reversibly and quickly binds Hg2+ and then undergoes a slow reversible course to inactivation. Furthermore, the rate constant of the forward reactions (k+0 is much larger than the rate constant of the reverse reactions (k-0. By combining with the fact that the enzyme activity is almost completely lost at high concentration, the enzyme is completely inactivated when the Hg2+ concentration is high enough. Conclusions These results suggest that Hg2+ has great impacts on the urease activity and the established inhibition kinetics model is suitable.

New monoclonal antibody-based test for Helicobacter pylori urease in gastric tissue.

Science.gov (United States)

Kim, Do Hyun; Kim, Ho Dong; Park, Hyeuk; Choi, Seung; Beom, Jae Won; Kim, Woo Jong; Park, Chang Kook; Lee, Young Jik; Park, Ju Young; Kim, Hyung Rag; Park, Chul; Joo, Young Eun; Jung, Young Do

2016-01-01

To evaluate a new monoclonal antibody for Helicobacter pylori urease in gastric tissue. A total of 107 volunteers were enrolled. All subjects underwent a (13)C-urea breath test and esophagogastroduodenoscopy. Gastric aspirates were analyzed for pH and ammonia. Six biopsy specimens in the gastric antrum and body were obtained for a rapid urease test and histology. The new monoclonal antibody-based H. pylori urease test (HPU) was performed to rapidly and qualitatively detect urease in two biopsy specimens. H. pylori infection was diagnosed in 73 subjects. The sensitivity and specificity of the HPU was 89% and 74%, respectively. The subjects were divided into two groups: one with true-positive and true-negative HPU results (n = 90) and the other with false-positive and false-negative HPU results (n = 17). Across all subjects, ammonia levels were 900.5 ± 646.7 and 604.3 ± 594.3 μmol/L (p > 0.05), and pH was 3.37 ± 1.64 and 2.82 ± 1.51 (p > 0.05). Sensitivity was higher in the presence of atrophic gastritis or intestinal metaplasia. HPU detected H. pylori in approximately 10 min. Gastric aspirate ammonia and pH levels did not affect the test results. Sensitivity was good in the presence of atrophic gastritis or intestinal metaplasia.

Application effects of coated urea and urease and nitrification inhibitors on ammonia and greenhouse gas emissions from a subtropical cotton field of the Mississippi delta region

International Nuclear Information System (INIS)

Tian, Zhou; Wang, Jim J.; Liu, Shuai; Zhang, Zengqiang; Dodla, Syam K.; Myers, Gerald

2015-01-01

Nitrogen (N) fertilization affects both ammonia (NH 3 ) and greenhouse gas (GHG) emissions that have implications in air quality and global warming potential. Different cropping systems practice varying N fertilizations. The aim of this study was to investigate the effects of applications of polymer-coated urea and urea treated with N process inhibitors: NBPT [N-(n-butyl)thiophosphoric triamide], urease inhibitor, and DCD [Dicyandiamide], nitrification inhibitor, on NH 3 and GHG emissions from a cotton production system in the Mississippi delta region. A two-year field experiment consisting of five treatments including the Check (unfertilized), urea, polymer-coated urea (ESN), urea + NBPT, and urea + DCD was conducted over 2013 and 2014 in a Cancienne loam (Fine-silty, mixed, superactive, nonacid, hyperthermic Fluvaquentic Epiaquepts). Ammonia and GHG samples were collected using active and passive chamber methods, respectively, and characterized. The results showed that the N loss to the atmosphere following urea-N application was dominated by a significantly higher emission of N 2 O-N than NH 3 -N and the most N 2 O-N and NH 3 -N emissions were during the first 30–50 days. Among different N treatments compared to regular urea, NBPT was the most effective in reducing NH 3 -N volatilization (by 58–63%), whereas DCD the most significant in mitigating N 2 O-N emissions (by 75%). Polymer-coated urea (ESN) and NBPT also significantly reduced N 2 O-N losses (both by 52%) over urea. The emission factors (EFs) for urea, ESN, urea-NBPT, urea + DCD were 1.9%, 1.0%, 0.2%, 0.8% for NH 3 -N, and 8.3%, 3.4%, 3.9%, 1.0% for N 2 O-N, respectively. There were no significant effects of different N treatments on CO 2 -C and CH 4 -C fluxes. Overall both of these N stabilizers and polymer-coated urea could be used as a mitigation strategy for reducing N 2 O emission while urease inhibitor NBPT for reducing NH 3 emission in the subtropical cotton production system of the

Urease Inhibition of Fixed Oils and Fractions of Caralluma tuberculata: Component Identification by GC-MS

International Nuclear Information System (INIS)

Khan, M. A.; Khan, H.; Saeed, M.; Rauf, A.; Basharat, T.; Khan, A.

2015-01-01

The in vitro urease inhibitory activity of fixed oil and various organic fractions of Caralluma tuberculata followed by GC-MS analysis of the fixed oil are described in this research article. The fixed oil caused marked attenuation of jack bean urease with half-maximal inhibitory concentration (IC50) of 2.97 mg/ml. The similar urease inhibitory profile was observed for chloroform and ethyl acetate fractions with IC50 values of 3.36 and 4.90 mg/ml, respectively. GC-MS analysis led to the identification of 20 different constituents of the fixed oil by their m/z ratio and retention time in comparison with the standard compounds. The major constituents were methyl linoleate (30.97%) followed by methyl octadecadienoate (19.16%), ethyl linolenate (13.70 %), and methyl palmitate (9.86 %). The fixed oil and organic fractions of C. tuberculata exhibited marked urease inhibition and thus provide scientific background for use of the plant as antiulcer agent. (author)

[Effects of elevated atmospheric CO2 and nitrogen application on cotton biomass, nitrogen utilization and soil urease activity].

Science.gov (United States)

Lyu, Ning; Yin, Fei-hu; Chen, Yun; Gao, Zhi-jian; Liu, Yu; Shi, Lei

2015-11-01

In this study, a semi-open-top artificial climate chamber was used to study the effect of CO2 enrichment (360 and 540 µmol · mol(-1)) and nitrogen addition (0, 150, 300 and 450 kg · hm(-2)) on cotton dry matter accumulation and distribution, nitrogen absorption and soil urease activity. The results showed that the dry matter accumulation of bud, stem, leaf and the whole plant increased significantly in the higher CO2 concentration treatment irrespective of nitrogen level. The dry matter of all the detected parts of plant with 300 kg · hm(-2) nitrogen addition was significantly higher than those with the other nitrogen levels irrespective of CO2 concentration, indicating reasonable nitrogen fertilization could significantly improve cotton dry matter accumulation. Elevated CO2 concentration had significant impact on the nitrogen absorption contents of cotton bud and stem. Compared to those under CO2 concentration of 360 µmol · mol(-1), the nitrogen contents of bud and stem both increased significantly under CO2 concentration of 540 µmol · mol(-1). The nitrogen content of cotton bud in the treatment of 300 kg · hm(-2) nitrogen was the highest among the four nitrogen fertilizer treatments. While the nitrogen contents of cotton stem in the treatments of 150 kg · hm(-2) and 300 kg · hm(-2) nitrogen levels were higher than those in the treatment of 0 kg · hm(-2) and 450 kg · hm(-2) nitrogen levels. The nitrogen content of cotton leaf was significantly influenced by the in- teraction of CO2 elevation and N addition as the nitrogen content of leaf increased in the treatments of 0, 150 and 300 kg · hm(-2) nitrogen levels under the CO2 concentration of 540 µmol · mol(-1). The nitrogen content in cotton root was significantly increased with the increase of nitrogen fertilizer level under elevated CO2 (540 µmol · mol(-1)) treatment. Overall, the cotton nitrogen absorption content under the elevated CO2 (540 µmol · mol(-1)) treatment was higher than that

Increased Incidence of Urolithiasis and Bacteremia During Proteus mirabilis and Providencia stuartii Coinfection Due to Synergistic Induction of Urease Activity

Science.gov (United States)

Armbruster, Chelsie E.; Smith, Sara N.; Yep, Alejandra; Mobley, Harry L. T.

2014-01-01

Background. Catheter-associated urinary tract infections (CaUTIs) are the most common hospital-acquired infections worldwide and are frequently polymicrobial. The urease-positive species Proteus mirabilis and Providencia stuartii are two of the leading causes of CaUTIs and commonly co-colonize catheters. These species can also cause urolithiasis and bacteremia. However, the impact of coinfection on these complications has never been addressed experimentally. Methods. A mouse model of ascending UTI was utilized to determine the impact of coinfection on colonization, urolithiasis, and bacteremia. Mice were infected with P. mirabilis or a urease mutant, P. stuartii, or a combination of these organisms. In vitro experiments were conducted to assess growth dynamics and impact of co-culture on urease activity. Results. Coinfection resulted in a bacterial load similar to monospecies infection but with increased incidence of urolithiasis and bacteremia. These complications were urease-dependent as they were not observed during coinfection with a P. mirabilis urease mutant. Furthermore, total urease activity was increased during co-culture. Conclusions. We conclude that P. mirabilis and P. stuartii coinfection promotes urolithiasis and bacteremia in a urease-dependent manner, at least in part through synergistic induction of urease activity. These data provide a possible explanation for the high incidence of bacteremia resulting from polymicrobial CaUTI. PMID:24280366

Oral Immunization with a Multivalent Epitope-Based Vaccine, Based on NAP, Urease, HSP60, and HpaA, Provides Therapeutic Effect on H. pylori Infection in Mongolian gerbils.

Science.gov (United States)

Guo, Le; Yang, Hua; Tang, Feng; Yin, Runting; Liu, Hongpeng; Gong, Xiaojuan; Wei, Jun; Zhang, Ying; Xu, Guangxian; Liu, Kunmei

2017-01-01

Epitope-based vaccine is a promising strategy for therapeutic vaccination against Helicobacter pylori ( H. pylori ) infection. A multivalent subunit vaccine containing various antigens from H. pylori is superior to a univalent subunit vaccine. However, whether a multivalent epitope-based vaccine is superior to a univalent epitope-based vaccine in therapeutic vaccination against H. pylori , remains unclear. In this study, a multivalent epitope-based vaccine named CWAE against H. pylori urease, neutrophil-activating protein (NAP), heat shock protein 60 (HSP60) and H. pylori adhesin A (HpaA) was constructed based on mucosal adjuvant cholera toxin B subunit (CTB), Th1-type adjuvant NAP, multiple copies of selected B and Th cell epitopes (UreA 27-53 , UreA 183-203 , HpaA 132-141 , and HSP60 189-203 ), and also the epitope-rich regions of urease B subunit (UreB 158-251 and UreB 321-385 ) predicted by bioinformatics. Immunological properties of CWAE vaccine were characterized in BALB/c mice model. Its therapeutic effect was evaluated in H. pylori -infected Mongolian gerbil model by comparing with a univalent epitope-based vaccine CTB-UE against H. pylori urease that was constructed in our previous studies. Both CWAE and CTB-UE could induce similar levels of specific antibodies against H. pylori urease, and had similar inhibition effect of H. pylori urease activity. However, only CWAE could induce high levels of specific antibodies to NAP, HSP60, HpaA, and also the synthetic peptides epitopes (UreB 158-172 , UreB 181-195 , UreB 211-225 , UreB 349-363 , HpaA 132-141 , and HSP60 189-203 ). In addition, oral therapeutic immunization with CWAE significantly reduced the number of H. pylori colonies in the stomach of Mongolian gerbils, compared with oral immunization using CTB-UE or H. pylori urease. The protection of CWAE was associated with higher levels of mixed CD4 + T cell (Th cell) response, IgG, and secretory IgA (sIgA) antibodies to H. pylori . These results indic ate

Oral Immunization with a Multivalent Epitope-Based Vaccine, Based on NAP, Urease, HSP60, and HpaA, Provides Therapeutic Effect on H. pylori Infection in Mongolian gerbils

Directory of Open Access Journals (Sweden)

Le Guo

2017-08-01

Full Text Available Epitope-based vaccine is a promising strategy for therapeutic vaccination against Helicobacter pylori (H. pylori infection. A multivalent subunit vaccine containing various antigens from H. pylori is superior to a univalent subunit vaccine. However, whether a multivalent epitope-based vaccine is superior to a univalent epitope-based vaccine in therapeutic vaccination against H. pylori, remains unclear. In this study, a multivalent epitope-based vaccine named CWAE against H. pylori urease, neutrophil-activating protein (NAP, heat shock protein 60 (HSP60 and H. pylori adhesin A (HpaA was constructed based on mucosal adjuvant cholera toxin B subunit (CTB, Th1-type adjuvant NAP, multiple copies of selected B and Th cell epitopes (UreA27–53, UreA183–203, HpaA132–141, and HSP60189–203, and also the epitope-rich regions of urease B subunit (UreB158–251 and UreB321–385 predicted by bioinformatics. Immunological properties of CWAE vaccine were characterized in BALB/c mice model. Its therapeutic effect was evaluated in H. pylori-infected Mongolian gerbil model by comparing with a univalent epitope-based vaccine CTB-UE against H. pylori urease that was constructed in our previous studies. Both CWAE and CTB-UE could induce similar levels of specific antibodies against H. pylori urease, and had similar inhibition effect of H. pylori urease activity. However, only CWAE could induce high levels of specific antibodies to NAP, HSP60, HpaA, and also the synthetic peptides epitopes (UreB158–172, UreB181–195, UreB211–225, UreB349–363, HpaA132–141, and HSP60189–203. In addition, oral therapeutic immunization with CWAE significantly reduced the number of H. pylori colonies in the stomach of Mongolian gerbils, compared with oral immunization using CTB-UE or H. pylori urease. The protection of CWAE was associated with higher levels of mixed CD4+ T cell (Th cell response, IgG, and secretory IgA (sIgA antibodies to H. pylori. These results indic

A semester-long project-oriented biochemistry laboratory based on Helicobacter pylori urease.

Science.gov (United States)

Farnham, Kate R; Dube, Danielle H

2015-01-01

Here we present the development of a 13 week project-oriented biochemistry laboratory designed to introduce students to foundational biochemical techniques and then enable students to perform original research projects once they have mastered these techniques. In particular, we describe a semester-long laboratory that focuses on a biomedically relevant enzyme--Helicobacter pylori (Hp) urease--the activity of which is absolutely required for the gastric pathogen Hp to colonize the human stomach. Over the course of the semester, students undertake a biochemical purification of Hp urease, assess the success of their purification, and investigate the activity of their purified enzyme. In the final weeks of the semester, students design and implement their own experiments to study Hp urease. This laboratory provides students with an understanding of the importance of biochemistry in human health while empowering them to engage in an active area of research. © 2015 The International Union of Biochemistry and Molecular Biology.

Preparation of tubular urease immobilized on the inner wall of glass tube by radiation-polymerization

Energy Technology Data Exchange (ETDEWEB)

Tanaka, Y; Hayashi, T; Kawashima, K [National Food Research Inst., Yatabe, Ibaraki (Japan); Oka, O

1981-03-01

A method to prepare immobilized urease on the inner wall of a glass tube by radiation-polymerization under frozen state was investigated. As a part of a continuous flow analyzer, i.w.. Technicon Auto Analyzer II, the immobilized urease tube of 1 cm length was set and used for the routine determination of urea. This flow-through system could measure urea concentration of up to 30 mM at rate of 30 samples per hour. The system were possible to assay 2000 to 3000 samples, continuously in practice. The activity of the urease tube stored in a refrigerator maintained 94% of the initial activity after 115 days.

Preparation of tubular urease immobilized on the inner wall of glass tube by radiation-polymerization

International Nuclear Information System (INIS)

Tanaka, Yoshikazu; Hayashi, Toru; Kawashima, Koji; Oka, Osamu.

1981-01-01

A method to prepare immobilized urease on the inner wall of a glass tube by radiation-polymerization under frozen state was investigated. As a part of a continuous flow analyzer, i.w.. Technicon Auto Analyzer II, the immobilized urease tube of 1 cm length was set and used for the routine determination of urea. This flow-through system could measure urea concentration of up to 30 mM at rate of 30 samples per hour. The system were possible to assay 2000 to 3000 samples, continuously in practice. The activity of the urease tube stored in a refrigirator maintained 94% of the initial activity after 115 days. (author)

Inhibition of Urease by Disulfiram, an FDA-Approved Thiol Reagent Used in Humans.

Science.gov (United States)

Díaz-Sánchez, Ángel Gabriel; Alvarez-Parrilla, Emilio; Martínez-Martínez, Alejandro; Aguirre-Reyes, Luis; Orozpe-Olvera, Jesica Aline; Ramos-Soto, Miguel Armando; Núñez-Gastélum, José Alberto; Alvarado-Tenorio, Bonifacio; de la Rosa, Laura Alejandra

2016-11-26

Urease is a nickel-dependent amidohydrolase that catalyses the decomposition of urea into carbamate and ammonia, a reaction that constitutes an important source of nitrogen for bacteria, fungi and plants. It is recognized as a potential antimicrobial target with an impact on medicine, agriculture, and the environment. The list of possible urease inhibitors is continuously increasing, with a special interest in those that interact with and block the flexible active site flap. We show that disulfiram inhibits urease in Citrullus vulgaris (CVU), following a non-competitive mechanism, and may be one of this kind of inhibitors. Disulfiram is a well-known thiol reagent that has been approved by the FDA for treatment of chronic alcoholism. We also found that other thiol reactive compounds (l-captopril and Bithionol) and quercetin inhibits CVU. These inhibitors protect the enzyme against its full inactivation by the thiol-specific reagent Aldrithiol (2,2'-dipyridyl disulphide, DPS), suggesting that the three drugs bind to the same subsite. Enzyme kinetics, competing inhibition experiments, auto-fluorescence binding experiments, and docking suggest that the disulfiram reactive site is Cys592, which has been proposed as a "hinge" located in the flexible active site flap. This study presents the basis for the use of disulfiram as one potential inhibitor to control urease activity.

Urease inhibition potential of Di-naphthodiospyrol from Diospyros lotus roots.

Science.gov (United States)

Rauf, Abdur; Uddin, Ghias; Raza, Muslam; Patel, Seema; Bawazeer, Saud; Ben Hadda, Taibi; Jehan, Noor; Mabkhot, Yahia Nasser; Khan, Ajmal; Mubarak, Mohammad S

2017-05-01

The dimeric napthoquione 5,8,4'-trihydroxy-1'-methoxy-6, 6'-dimethyl-7,3'-binaphtyl-1,4,5',8'-tetraone (1) was isolated from the chloroform fraction of Diospyros lotus extract. Compound 1 was screened for its inhibitory effects against four enzymes: urease, phosphodiesterase-I, carbonic anhydrase-II and α-chymotrypsin, and showed selective activity against urease enzyme with an IC 50 value of 254.1 ± 3.82 μM as compared to the standard thiourea (IC 50  = 21 ± 0.11 μM). Furthermore, in silico docking study was carried out to explain the molecular mechanism of compound 1 against the target receptor.

Novel fabrication method of the peritoneal dialysis filter using silk fibroin with urease fixation system.

Science.gov (United States)

Moon, Bo Mi; Choi, Myung-Jin; Sultan, Md Tipu; Yang, Jae Won; Ju, Hyung Woo; Lee, Jung Min; Park, Hyun Jung; Park, Ye Ri; Kim, Soo Hyeon; Kim, Dong Wook; Lee, Min Chae; Jeong, Ju Yeon; Lee, Ok Joo; Sung, Gun Yong; Park, Chan Hum

2017-10-01

During the last decade, there has been a great advance in the kidney dialysis system by wearable artificial kidney (WAK) system for end-stage renal disease patients. Uremic solute removal and water regeneration system are the most prerequisite for WAK to work properly. In this study, we designed a filtering membrane system by using immobilized urease silk fibroin filter and evaluated its comparative effectiveness with a PVDF filtering system in peritoneal dialysate regeneration system by urea removal efficacy. We evaluated this membrane's characteristic and performances by conducting SEM-EDX analyze, water-binding abilities and porosity test, removal abilities of urea, cytotoxicity assay and enzyme activity assay. Under the condition for optimization of urease, the percentage removal of urea was about 40% and 60% in 50 mg/dL urea solution by urease immobilized PVDF and silk fibroin scaffolds, respectively. The batch experimental result showed that immobilized filter removed more than 50% of urea in 50 mg/dL urea solution. In addition silk fibroin with urease filter removed 90 percent of urea in the peritoneal dialysate after 24 h filtration. We suggest that silk fibroin with urease fixation filter can be used more effectively for peritoneal dialysate regeneration system, which have hydrophilic property and prolonged enzyme activity. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2136-2144, 2017. © 2016 Wiley Periodicals, Inc.

Inhibition studies of soybean (Glycine max) urease with heavy metals, sodium salts of mineral acids, boric acid, and boronic acids.

Science.gov (United States)

Kumar, Sandeep; Kayastha, Arvind M

2010-10-01

Various inhibitors were tested for their inhibitory effects on soybean urease. The K(i) values for boric acid, 4-bromophenylboronic acid, butylboronic acid, and phenylboronic acid were 0.20 +/- 0.05 mM, 0.22 +/- 0.04 mM, 1.50 +/- 0.10 mM, and 2.00 +/- 0.11 mM, respectively. The inhibition was competitive type with boric acid and boronic acids. Heavy metal ions including Ag(+), Hg(2+), and Cu(2+) showed strong inhibition on soybean urease, with the silver ion being a potent inhibitor (IC(50) = 2.3 x 10(-8) mM). Time-dependent inhibition studies exhibited biphasic kinetics with all heavy metal ions. Furthermore, inhibition studies with sodium salts of mineral acids (NaF, NaCl, NaNO(3), and Na(2)SO(4)) showed that only F(-) inhibited soybean urease significantly (IC(50) = 2.9 mM). Competitive type of inhibition was observed for this anion with a K(i) value of 1.30 mM.

Functional expression of a heterologous nickel-dependent, ATP-independent urease in Saccharomyces cerevisiae.

Science.gov (United States)

Milne, N; Luttik, M A H; Cueto Rojas, H F; Wahl, A; van Maris, A J A; Pronk, J T; Daran, J M

2015-07-01

In microbial processes for production of proteins, biomass and nitrogen-containing commodity chemicals, ATP requirements for nitrogen assimilation affect product yields on the energy producing substrate. In Saccharomyces cerevisiae, a current host for heterologous protein production and potential platform for production of nitrogen-containing chemicals, uptake and assimilation of ammonium requires 1 ATP per incorporated NH3. Urea assimilation by this yeast is more energy efficient but still requires 0.5 ATP per NH3 produced. To decrease ATP costs for nitrogen assimilation, the S. cerevisiae gene encoding ATP-dependent urease (DUR1,2) was replaced by a Schizosaccharomyces pombe gene encoding ATP-independent urease (ure2), along with its accessory genes ureD, ureF and ureG. Since S. pombe ure2 is a Ni(2+)-dependent enzyme and Saccharomyces cerevisiae does not express native Ni(2+)-dependent enzymes, the S. pombe high-affinity nickel-transporter gene (nic1) was also expressed. Expression of the S. pombe genes into dur1,2Δ S. cerevisiae yielded an in vitro ATP-independent urease activity of 0.44±0.01 µmol min(-1) mg protein(-1) and restored growth on urea as sole nitrogen source. Functional expression of the Nic1 transporter was essential for growth on urea at low Ni(2+) concentrations. The maximum specific growth rates of the engineered strain on urea and ammonium were lower than those of a DUR1,2 reference strain. In glucose-limited chemostat cultures with urea as nitrogen source, the engineered strain exhibited an increased release of ammonia and reduced nitrogen content of the biomass. Our results indicate a new strategy for improving yeast-based production of nitrogen-containing chemicals and demonstrate that Ni(2+)-dependent enzymes can be functionally expressed in S. cerevisiae. Copyright © 2015 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

Evaluation of Antimicrobial Activity of Probiotic Lactobacillus Strains against Growth and Urease Activity of Proteus spp.

Directory of Open Access Journals (Sweden)

Leila Goudarzi

2017-10-01

Full Text Available Background:    Nowadays, the use of probiotic bacteria for the prevention and treatment of urinary tract infections is growing. Lactobacillus, as probiotic bacterial genus, is well known for its benefits for the human health.Methods:      The effects of partially purified antimicrobial compounds (bacteriocins and biosurfactants of Lactobacillus strains was assessed and their capacity to in vitro inhibit growth and urease production of various strains of Proteus spp, was studied. Inhibition of the urease production of Proteus spp. at sub-MIC levels was screened using spectrophotometry method.  Results:   Results revealed that semi-purified bacteriocins of L. acidophilus and L. plantarum showed a greater inhibitory activity on the bacterial urease, compared to biosurfactants of L. rhamnosus, L. casei and L. fermentum (P < 0.05.Conclusion:    It can be concluded that bacteriocins may affect Proteus pathogenesis by inhibition of the bacterial urease activity and therefore eliminate the stone formation by these bacteria.

Diagnosis of Helicobacter pylori infection; Culture, microscopy of biopsy smears, and the rapid urease test compared with the sup 14 C-urea breath test. Diagnostikk av Helicobacter pylori-infeksjon; Urease hurtigtest, mikroskopi av utstryk, og dyrking av ventrikkelbiopsi sammenlignet med sup 14 C-urea-pusteproeven

Energy Technology Data Exchange (ETDEWEB)

Nysaeter, G; Berstad, K; Weberg, R; Berstad, A; Hardardottir, H [Haukeland Hospital, Bergen (Norway)

1992-08-01

By employing the {sup 14}C-urea breath test as the reference methods the authors determined the specificity and sensitivity of three bioptic methods for diagnosis of Helicobacter pylori infection in 103 subjects. All biopsy specimens were obtained from the gastric antrum. For culture the specificity was 100%. Its applicability was reduced, however, by a low sensitivity (73.8%) and a delay of several days before the final result was available. Microscopy of Loeffler-stained biopsy smears yielded a specificity of 100% and a sensitivity of 92.9%, but the method was regarded time-consuming. The rapid urease test yielded a specificity of 98.4% and a sensitivity of 85.7%. Being quick, simple and inexpensive, the rapid urease test is well suited for routine use in gastroscopy. 17 refs., 4 tabs.

Synthesis and molecular docking study of piperazine derivatives as potent urease inhibitors.

Science.gov (United States)

Taha, Muhammad; Wadood, Abdul

2018-04-13

Urease is known to be one of the major causes of diseases induced by Helicobacter pylori, thus allow them to survive at low pH inside the stomach and thereby, play an important role in the pathogenesis of gastric and peptic ulcer, apart from cancer as well. Keeping in view the great importance of urease inhibitors, here in this study we have synthesized piperazine derivatives (1-15) and evaluated for their urease inhibitory activity. All analogs showed excellent inhibitory potential with IC 50 values ranging between 1.1 ± 0.01 and 33.40 ± 1.50 µM when compared with the standard inhibitor thiourea (IC 50  = 21.30 ± 1.10 µM). Structure activity relationship has been established for all compounds which are mainly based upon the substitution on phenyl ring. Molecular docking study was performed in order to understand the binding interaction of the compounds in the active site of enzyme. Copyright © 2018 Elsevier Inc. All rights reserved.

First report of urease activity in the novel systemic fungal pathogen Emergomyces africanus: a comparison with the neurotrope Cryptococcus neoformans.

Science.gov (United States)

Lerm, Barbra; Kenyon, Chris; Schwartz, Ilan S; Kroukamp, Heinrich; de Witt, Riaan; Govender, Nelesh P; de Hoog, G Sybren; Botha, Alfred

2017-11-01

Cryptococcus neoformans is an opportunistic pathogen responsible for the AIDS-defining illness, cryptococcal meningitis. During the disease process, entry of cryptococcal cells into the brain is facilitated by virulence factors that include urease enzyme activity. A novel species of an Emmonsia-like fungus, recently named Emergomyces africanus, was identified as a cause of disseminated mycosis in HIV-infected persons in South Africa. However, in contrast to C. neoformans, the enzymes produced by this fungus, some of which may be involved in pathogenesis, have not been described. Using a clinical isolate of C. neoformans as a reference, the study aim was to confirm, characterise and quantify urease activity in E. africanus clinical isolates. Urease activity was tested using Christensen's urea agar, after which the presence of a urease gene in the genome of E. africanus was confirmed using gene sequence analysis. Subsequent evaluation of colorimetric enzyme assay data, using Michaelis-Menten enzyme kinetics, revealed similarities between the substrate affinity of the urease enzyme produced by E. africanus (Km ca. 26.0 mM) and that of C. neoformans (Km ca. 20.6 mM). However, the addition of 2.5 g/l urea to the culture medium stimulated urease activity of E. africanus, whereas nutrient limitation notably increased cryptococcal urease activity. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Production of Autoantibodies by Murine B-1a Cells Stimulated with Helicobacter pylori Urease through Toll-Like Receptor 2 Signaling ▿ †

Science.gov (United States)

Kobayashi, Fumiko; Watanabe, Eri; Nakagawa, Yohko; Yamanishi, Shingo; Norose, Yoshihiko; Fukunaga, Yoshitaka; Takahashi, Hidemi

2011-01-01

Helicobacter pylori infection is associated with several autoimmune diseases, in which autoantibody-producing B cells must be activated. Among these B cells, CD5-positive B-1a cells from BALB/c mice were confirmed to secrete autoantibodies when cocultured with purified H. pylori urease in the absence of T cells. To determine the mechanisms for autoantibody production, CD5-positive B-1a cells were sorted from murine spleen cells and stimulated with either purified H. pylori urease or H. pylori coated onto plates (referred to hereafter as plate-coated H. pylori), and autoantibody production was measured by enzyme-linked immunosorbent assay (ELISA). Complete urease was not secreted from H. pylori but was visually expressed over the bacterium-like endotoxin. Urease-positive plated-coated H. pylori stimulated B-1a cells to produce autoantibodies, although urease-deficient isotype-matched H. pylori did not. Autoantibody secretion by B-1a cells was inhibited when bacteria were pretreated with anti-H. pylori urease-specific antibody having neutralizing ability against urease enzymatic activity but not with anti-H. pylori urease-specific antibody without neutralizing capacity. The B-1a cells externally express various Toll-like receptors (TLRs): TLR1, TLR2, TLR4, and TLR6. Among the TLRs, blocking of TLR2 on B-1a cells with a specific monoclonal antibody (MAb), T2.5, inhibited autoantibody secretion when B-1a cells were stimulated with plate-coated H. pylori or H. pylori urease. Moreover, B-1a cells from TLR2-knockout mice did not produce those autoantibodies. The present study provides evidence that functional urease expressed on the surface of H. pylori will directly stimulate B-1a cells via innate TLR2 to produce various autoantibodies and may induce autoimmune disorders. PMID:21947775

Cascading reaction of arginase and urease on a graphene-based FET for ultrasensitive, real-time detection of arginine.

Science.gov (United States)

Berninger, Teresa; Bliem, Christina; Piccinini, Esteban; Azzaroni, Omar; Knoll, Wolfgang

2018-09-15

Herein, a biosensor based on a reduced graphene oxide field effect transistor (rGO-FET) functionalized with the cascading enzymes arginase and urease was developed for the detection of L-arginine. Arginase and urease were immobilized on the rGO-FET sensing surface via electrostatic layer-by-layer assembly using polyethylenimine (PEI) as cationic building block. The signal transduction mechanism is based on the ability of the cascading enzymes to selectively perform chemical transformations and prompt local pH changes, that are sensitively detected by the rGO-FET. In the presence of L-arginine, the transistors modified with (PEI/urease(arginase)) multilayers showed a shift in the Dirac point due to the change in the local pH close to the graphene surface, produced by the catalyzed urea hydrolysis. The transistors were able to monitor L-arginine in the 10-1000 μM linear range with a LOD of 10 μM, displaying a fast response and a good long-term stability. The sensor showed stereospecificity and high selectivity in the presence of non-target amino acids. Taking into account the label-free, real-time measurement capabilities and the easily quantifiable, electronic output signal, this biosensor offers advantages over state-of-the-art L-arginine detection methods. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Genome sequence of a urease-positive Campylobacter lari strain

Science.gov (United States)

Campylobacter lari is frequently isolated from shore birds and can cause illness in humans. Here we report the draft whole genome sequence of an urease-positive strain of C. lari that was isolated in estuarial water on the coast of Delaware, USA....

The Importance of Urease in Acid Protection for the Gastric-colonising Bacteria Helicobacter pylori and Helicobacter felis sp. nov.

OpenAIRE

Ferrero, R. L.; Lee, A.

2011-01-01

The urease of the gastric pathogen Helicobacter pylori shares numerous characteristics with the urease of a bacterium isolated from cat gastric mucosa, Helicobacter felis sp. nov. The native enzymes have similar apparent molecular weights and, when subjected to SDS-PAGE, disassociate into active subunits of comparable relative mobilities. In contrast, a bacterium (St1) that colonises rodent ileal mucosa, and is related to Helicobacter spp., expresses a distinct urease from those of the gastri...

Catalytic performances of chemically immobilized urease under static and dynamic conditions: A comparative study

OpenAIRE

Yürekli, Yılmaz; Alsoy Altınkaya, Sacide

2011-01-01

Immobilized urease has been used for direct removal of urea from aqueous solution and as biological sensing material in the preparation of urea biosensors. The former application is carried out under dynamic condition using ultrafiltration membrane either in tubular form or in flat sheet, while the latter is used in static condition. In this study, the performance of chemically immobilized urease on poly(acrylonitrile-co-sodium methallyl sulfonate) ultrafiltration membrane was determined unde...

Enhanced Peroxide Resistance of In Vitro Mutagenized Fluorideresistant Klebsiella pneumoniae Ureases for Catalytic Buffering of Agent Decontamination Reactions

National Research Council Canada - National Science Library

Fry, Ilona J; DeFrank, Joseph J

2004-01-01

.... Fluoride-resistant (FR) ureases developed previously in our laboratory were >95% inhibited by 1% hydrogen peroxide. To overcome this problem, the FR mutant urease structural genes of Klebsiella pneumoniae were mutagenized in vitro in an E...

Application effects of coated urea and urease and nitrification inhibitors on ammonia and greenhouse gas emissions from a subtropical cotton field of the Mississippi delta region

Energy Technology Data Exchange (ETDEWEB)

Tian, Zhou [College of Resources and Environment, Northwest A& F University, Yangling, Shaanxi (China); School of Plant, Environment & Soil Sciences, Louisiana State University Agricultural Center, Baton Rouge, LA 70803 (United States); Wang, Jim J., E-mail: jjwang@agcenter.lsu.edu [School of Plant, Environment & Soil Sciences, Louisiana State University Agricultural Center, Baton Rouge, LA 70803 (United States); Liu, Shuai [College of Resources and Environment, Northwest A& F University, Yangling, Shaanxi (China); School of Plant, Environment & Soil Sciences, Louisiana State University Agricultural Center, Baton Rouge, LA 70803 (United States); Zhang, Zengqiang, E-mail: zqzhang@nwsuaf.edu.cn [College of Resources and Environment, Northwest A& F University, Yangling, Shaanxi (China); Dodla, Syam K.; Myers, Gerald [School of Plant, Environment & Soil Sciences, Louisiana State University Agricultural Center, Baton Rouge, LA 70803 (United States)

2015-11-15

Nitrogen (N) fertilization affects both ammonia (NH{sub 3}) and greenhouse gas (GHG) emissions that have implications in air quality and global warming potential. Different cropping systems practice varying N fertilizations. The aim of this study was to investigate the effects of applications of polymer-coated urea and urea treated with N process inhibitors: NBPT [N-(n-butyl)thiophosphoric triamide], urease inhibitor, and DCD [Dicyandiamide], nitrification inhibitor, on NH{sub 3} and GHG emissions from a cotton production system in the Mississippi delta region. A two-year field experiment consisting of five treatments including the Check (unfertilized), urea, polymer-coated urea (ESN), urea + NBPT, and urea + DCD was conducted over 2013 and 2014 in a Cancienne loam (Fine-silty, mixed, superactive, nonacid, hyperthermic Fluvaquentic Epiaquepts). Ammonia and GHG samples were collected using active and passive chamber methods, respectively, and characterized. The results showed that the N loss to the atmosphere following urea-N application was dominated by a significantly higher emission of N{sub 2}O-N than NH{sub 3}-N and the most N{sub 2}O-N and NH{sub 3}-N emissions were during the first 30–50 days. Among different N treatments compared to regular urea, NBPT was the most effective in reducing NH{sub 3}-N volatilization (by 58–63%), whereas DCD the most significant in mitigating N{sub 2}O-N emissions (by 75%). Polymer-coated urea (ESN) and NBPT also significantly reduced N{sub 2}O-N losses (both by 52%) over urea. The emission factors (EFs) for urea, ESN, urea-NBPT, urea + DCD were 1.9%, 1.0%, 0.2%, 0.8% for NH{sub 3}-N, and 8.3%, 3.4%, 3.9%, 1.0% for N{sub 2}O-N, respectively. There were no significant effects of different N treatments on CO{sub 2}-C and CH{sub 4}-C fluxes. Overall both of these N stabilizers and polymer-coated urea could be used as a mitigation strategy for reducing N{sub 2}O emission while urease inhibitor NBPT for reducing NH{sub 3} emission

Lipoxygenase and urease inhibition of extracts of polygonatum verticillatum rhizome: augmented by its isolated compound, santonin

International Nuclear Information System (INIS)

Khan, H.; Saeed, M.; Saeed, M.

2014-01-01

The present study was designed to explore the enzyme inhibitory profile of extracts of rhizome of Polygonatum verticillatum against lipoxygenase and urease. When tested against lipoxygenase, ethyl acetate fraction was found the most potent (IC50: 69 micro g/ml) and the overall IC50 values of different extracts ranged from 69-174 micro g/ml. In urease assay, n-butanol was the most potent fraction (IC50: 169 micro g/ml) while the overall IC50 values were in the range of 169-288 micro g/ml. Bioactivity guided chromatography led to the isolation of compound 1 which was characterized as santonin on the basis of various spectroscopic techniques. When santonin was tested against lipoxygenase and urease, it showed potent inhibition of lipoxygenase (IC50: 27.4 micro M) but did not attenuate the urease activity. Our findings provided strong evidence for the enzyme inhibitory profile of the extracts of P. verticillatum rhizome and its isolated compound. Thus results are consistent with the traditional use of the plant as an anti-inflammatory agent. (author)

Design, synthesis, molecular docking, anti-Proteus mirabilis and urease inhibition of new fluoroquinolone carboxylic acid derivatives.

Science.gov (United States)

Abdullah, Mohammed A A; Abuo-Rahma, Gamal El-Din A A; Abdelhafez, El-Shimaa M N; Hassan, Heba A; Abd El-Baky, Rehab M

2017-02-01

New hydroxamic acid, hydrazide and amide derivatives of ciprofloxacin in addition to their analogues of levofloxacin were prepared and identified by different spectroscopic techniques. Some of the prepared compounds revealed good activity against the urease splitting bacteria, Proteus mirabilis. The urease inhibitory activity was investigated using indophenol method. Most of the tested compounds showed better activity than the reference acetohydroxamic acid (AHA). The ciprofloxacin hydrazide derivative 3a and levofloxacin hydroxamic acid 7 experienced the highest activity (IC 50 =1.22μM and 2.20μM, respectively). Molecular docking study revealed high spontaneous binding ability of the tested compounds to the active site of urease. Copyright © 2016 Elsevier Inc. All rights reserved.

An immunoradiometric assay for Helicobacter pylori urease B in serum

International Nuclear Information System (INIS)

Bai Yanyan; Wang Zhaoyue; Bai Xia; Ruan Changgen; Miao Jingcheng; Gu Guanbing

2008-01-01

Objective: The aim of this study was to establish and evaluate a novel immunoradiometric assay (IRMA) for detecting helicobacter pylori (HP) urease B (ureB) in serum. Methods: HP ureB was prepared by the DNA recombinant technique. Monoclonal antibodies against HP ureB were produced by hybridoma technique and were used to establish IRMA for detecting HP ureB. Fifty patients with chronic gastric diseases were recruited in this study, including 36 with gastric ulcer disease, 9 with chronic gastritis and 5 with gastric cancer. The IRMA was compared with rapid urease test (RUT), polymerase chain reaction (PCR) test and direct-ELISA test of serum anti-ureB antibody, using HP culture from gastric biopsy samples as a 'golden standard'. Results: The sensitivity and specificity of IRMA for HP ureB were 94.6% and 76.9%, respectively, with positive and negative predictive values being 92.1% and 83.3%. The sensitivity and specificity of RUT, PCR and serum anti-ureB antibody test were 94.6% and 23.1% , 66.8% and 84.6%, 86.5% and 38.5%, respectively. IRMA and the test of serum anti-ureB antibody was not significantly different from the 'golden standard' (X 2 =1.165, P>0.05), but RUT and PCR showed statistically significant difference with the 'gold standard' (X 2 =5.333, 9.436; all P<0.05). Conclusion: IRMA for HP ureB antigen is a sensitive and specific method for detection of HP infection, and can be used in the study of etiology and pathogenesis of gastric and some other related diseases. (authors)

Hemolytic and urease activities in vibrios isolated from fresh and frozen oysters

Directory of Open Access Journals (Sweden)

Renata Albuquerque Costa

2013-01-01

Full Text Available INTRODUCTION: The present study aimed to survey the Vibrio microbiota of oysters (Crassostrea rhizophorae obtained from restaurants in Fortaleza, State of Ceará, Brazil, and to identify virulence factors. METHODS: The isolated vibrios were submitted to biochemical identification and were tested for hemolytic and urease activities. RESULTS: The isolated strains belonged to 13 species, with predominance of Vibrio mimicus. Of the strain isolates only from fresh samples, 20.5% and 2.8% showed hemolytic and urease activities, respectively. CONCLUSIONS: The findings support the little-publicized claim that Vibrio species other than V. parahaemolyticus and V. vulnificus can represent a health risk to public health.

Phytochemical analysis, antimicrobial, antioxidant and urease inhibitory potential of Cyphostemma digitatum Lam.

Science.gov (United States)

Khan, Rasool; Saif, Abdullah Qasem; Quradha, Mohammad Mansour; Ali, Jawad; Rauf, Abdur

2015-01-01

In this paper we report the antimicrobial, antiradical and urease inhibitory potential along with photochemical investigation of the crude extracts of Cyphostemma digitatum Lam. Phytochemical screening of both the crude (hot/cold) alcoholic and aqueous extracts of C. digitatum showed the presence of alkaloids, flavonoids, saponins, coumarins, steroids, terpenoids and tannins. The crude methanolic extract (hot/cold) exhibited good antioxidant activity, while the aqueous extract was a weak antioxidant. The crude methanolic extract was found to be more active against Bacillus subtilis, while both the extracts showed moderate antifungal potential, the methanolic crude extract showed good urease inhibitory activity compared with the aqueous crude extract.

Insecticidal effect of Canavalia ensiformis major urease on nymphs of the milkweed bug Oncopeltus fasciatus and characterization of digestive peptidases.

Science.gov (United States)

Defferrari, Marina S; Demartini, Diogo R; Marcelino, Thiago B; Pinto, Paulo M; Carlini, Celia R

2011-06-01

Jackbean (Canavalia ensiformis) ureases are entomotoxic upon the release of internal peptides by insect's digestive enzymes. Here we studied the digestive peptidases of Oncopeltus fasciatus (milkweed bug) and its susceptibility to jackbean urease (JBU). O. fasciatus nymphs fed urease showed a mortality rate higher than 80% after two weeks. Homogenates of midguts dissected from fourth instars were used to perform proteolytic activity assays. The homogenates hydrolyzed JBU in vitro, yielding a fragment similar in size to known entomotoxic peptides. The major proteolytic activity at pH 4.0 upon protein substrates was blocked by specific inhibitors of aspartic and cysteine peptidases, but not significantly affected by inhibitors of metallopeptidases or serine peptidases. The optimal activity upon N-Cbz-Phe-Arg-MCA was at pH 5.0, with complete blockage by E-64 in all pH tested. Optimal activity upon Abz-AIAFFSRQ-EDDnp (a substrate for aspartic peptidases) was detected at pH 5.0, with partial inhibition by Pepstatin A in the pH range 2-8. Fluorogenic substrates corresponding to the N- and C-terminal regions flanking a known entomotoxic peptide within urease sequence were also tested. While the midgut homogenate did not hydrolyze the N-terminal peptide, it cleaved the C-terminal peptide maximally at pH 4.0-5.0, and this activity was inhibited by E-64 (10 μM). The midgut homogenate was submitted to ion-exchange chromatography followed by gel filtration. A 22 kDa active fraction was obtained, resolved in SDS-PAGE (12%), the corresponding band was in-gel digested by trypsin, the peptides were analyzed by mass spectrometry, retrieving a cathepsin L protein. The purified cathepsin L was shown to have at least two possible cleavage sites within the urease sequence, and might be able to release a known insecticidal peptide in a single or cascade event. The results suggest that susceptibility of O. fasciatus nymphs to jackbean urease is, like in other insect models, due mostly

Ionic effect investigation of a potentiometric sensor for urea and surface morphology observation of entrapped urease/polypyrrole matrix.

Science.gov (United States)

Syu, Mei-Jywan; Chang, Yu-Sung

2009-04-15

Potentio-dynamic polymerization of buffered urease and pyrrole monomer onto carbon papers was conducted to fabricate an immobilized urease electrode for measuring the urea concentration. To use carbon paper as the substrate for the electro-growth of polypyrrole matrix not only created sufficient adhesion of the conducting polymer layer but also provided superior entrapment of urease enzymes. The potentiometric response corresponding to ammonia, the product formed from the urease catalyzed urea reaction, was employed for the urea concentration measurement. Scanning electron microscopic photographs showed that the polypyrrole matrix deposited on the carbon papers appeared to be of a cylindrical nanotube shape. The charge density applied in the polymerization was found to affect the potentiometric response while the potential-scanning rate showed minor influence. The composite electrodes had high sensitivity in urea detection, showing a response linear to the logarithm of the urea concentration in the range of 10(-3) to 10 mM. The detection of urea solution prepared in water and buffer was also compared. Ionic effect on the sensing of urea solution was investigated. By comparing the data reported in literature, the urease/polypyrrole/carbon paper electrode developed in this work showed superior long-term stability and reusability. The detection of urea in serum was also well performed.

Urease from Staphylococcus saprophyticus. Some properties and inhibition by metal ions

Energy Technology Data Exchange (ETDEWEB)

Glemzha, A A; Kovzan, V B; Yuodval' kite, D Yu

1984-12-01

Data concerning the molecular weight, the dependence of the enzymic rate of the pH and the concentration of the substrate, and the effect of metal ions on urease activity are presented and discussed. Precipitation with ethanol was used to isolate a urease preparation with a specific activity of 250-300 units/mg of protein from Staphylococcus saprophyticus cells. The molecular weight of the enzyme, determined by gel filtration on a Sephadex G-200 column is 250,000. Maximum activity of St. saprophyticus urease occurred at pH 6.8-7.0; the K/sub m/ value, at 30/sup 0/C (pH 6.8) equalled 7.36 x 10/sup -3/ M, V/sub max/ is 1.5 ..mu..mol NH/sub 3//min. The enzyme was reversibly inhibited by heavy metal ions. The sequence of inhibiting effect of the ions studied is: Ag/sup +/>Ni/sup 2 +/>Cd/sup 2 +/>Co/sup 2 +/>Hg/sup 2 +/>Cu/sup 2 +/>Zn/sup 2 +/>Pb/sup 2 +/ and pK of groups of the active center equal 5.0-5.25 and 8.25 and are near in value to those of the imidazole ring of histidine (0.5-7.0) and the Sh-group of cysteine (8.3-8.6). 19 references, 4 figures.

Immobilization of urease on copper chelated EC-Tri beads and ...

African Journals Online (AJOL)

Maximum reaction rate (Vmax) and Michaelis-Menten constant (km) were determined for the free and immobilized enzymes. Various characteristics of immobilized urease such as the temperature activity curve, thermal stability, operational stability and storage stability were evaluated. The results demonstrated that triazole ...

Nutrient content of wheat and corn in response to the application of urea and the urease inhibitor NPBT

Science.gov (United States)

A field study was conducted to evaluate the effects of the addition of two different urease inhibitors on the volatilization of ammonia from top dressed ammonia sources on winter wheat and dent corn. Two commercial urease inhibitors (NY and AG) were tested. Treatments included compost, compost+NY, u...

Production and characterization of a camelid single domain antibody-urease enzyme conjugate for the treatment of cancer.

Science.gov (United States)

Tian, Baomin; Wong, Wah Yau; Hegmann, Elda; Gaspar, Kim; Kumar, Praveen; Chao, Heman

2015-06-17

A novel immunoconjugate (L-DOS47) was developed and characterized as a therapeutic agent for tumors expressing CEACAM6. The single domain antibody AFAIKL2, which targets CEACAM6, was expressed in the Escherichia coli BL21 (DE3) pT7-7 system. High purity urease (HPU) was extracted and purified from Jack bean meal. AFAIKL2 was activated using N-succinimidyl [4-iodoacetyl] aminobenzoate (SIAB) as the cross-linker and then conjugated to urease. The activation and conjugation reactions were controlled by altering pH. Under these conditions, the material ratio achieved conjugation ratios of 8-11 antibodies per urease molecule, the residual free urease content was practically negligible (95%) L-DOS47 conjugate was produced using only ultradiafiltration to remove unreacted antibody and hydrolyzed cross-linker. L-DOS47 was characterized by a panel of analytical techniques including SEC, IEC, Western blot, ELISA, and LC-MS(E) peptide mapping. As the antibody-urease conjugate ratio increased, a higher binding signal was observed. The specificity and cytotoxicity of L-DOS47 was confirmed by screening in four cell lines (BxPC-3, A549, MCF7, and CEACAM6-transfected H23). BxPC-3, a CEACAM6-expressing cell line was found to be most susceptible to L-DOS47. L-DOS47 is being investigated as a potential therapeutic agent in human phase I clinical studies for nonsmall cell lung cancer.

Application of original assemblies of polyelectrolytes, urease and electrodeposited polyaniline as sensitive films of potentiometric urea biosensors

International Nuclear Information System (INIS)

Buron, Cédric C.; Quinart, Mélanie; Vrlinic, Tjasa; Yunus, Sami; Glinel, Karine; Jonas, Alain M.; Lakard, Boris

2014-01-01

Highlights: • Elaboration of original polymer materials using self-assembly and electrochemistry. • In situ monitoring of the growth of the polymer materials. • Development of urea electrochemical sensors using a home-made mini-potentiostat. - Abstract: Original assemblies were prepared for use as sensitive films of potentiometric enzyme urea sensors, and compared to identify the more efficient structure with respect to stability. These films included electrodeposited polyaniline, used as transducer, urease, used as catalyst, and biocompatible polyelectrolytes, used as a matrix to preserve the integrity of the enzyme in the sensitive film. Two kinds of assemblies were done: the first one consisted in the adsorption of urease onto a polyaniline film followed by the adsorption of a chitosan-carboxymethylpullulan multilayer film, while the second one consisted in the adsorption of a urease-chitosan multilayer film onto an electrodeposited polyaniline film. The morphological features and growth of these assemblies were characterized by scanning electron microscopy and quartz crystal microbalance, respectively. This allowed us to demonstrate that the assemblies are successfully formed onto the electrodes of the sensors. The potentiometric responses of both assemblies were then measured as a function of urea concentration using a home-made portable potentiostat. The electrochemical response of resulting sensors was fast and sensitive for both types of assemblies, but the stability in time was much better for the films obtained from alternative adsorption of urease and chitosan onto a layer of urease adsorbed over electrodeposited polyaniline

Urease activity as an index for assessing the maturity of cow manure and wheat residue vermicomposts.

Science.gov (United States)

Sudkolai, Saber Tayebi; Nourbakhsh, Farshid

2017-06-01

The establishment of a reliable index is an essential need to assess the degree of stability and maturity of solid wastes vermicomposts. The objective of this study was to investigate the effects of vermicomposting process on some chemical (pH, EC, OC, TN, lignin and C:N ratio) and biochemical properties of the cow manure (CM) and wheat residue (WR). Results demonstrated that during vermicomposting process of CM and WR urease activity was highly correlated with the time of vermicomposting (r=-0.97 ∗∗ for CM and r=-0.99 ∗∗ for WR), and well able to show the stability of organic waste. The urease activity showed significant correlations with the C:N ratio during the vermicomposting of CM and WR (r=0.89 ∗ and r=0.93 ∗∗ respectively) therefore it can be considered as a reliable indicator for determining the maturity and stability of organic wastes during vermicomposting process. Copyright © 2017. Published by Elsevier Ltd.

Hybrid Pharmacophoric Approach in the Design and Synthesis of Coumarin Linked Pyrazolinyl as Urease Inhibitors, Kinetic Mechanism and Molecular Docking.

Science.gov (United States)

Saeed, Aamer; Mahesar, Parvez Ali; Channar, Pervaiz Ali; Larik, Fayaz Ali; Abbas, Qamar; Hassan, Mubashir; Raza, Hussain; Seo, Sung-Yum

2017-08-01

The current research article reports the synthesis of coumarinyl pyrazolinyl thioamide derivatives and their biological activity as inhibitors of jack bean urease. The coumarinyl pyrazolinyl thioamides were synthesized by reacting thiosemicarbazide with newly synthesized chalcones to afford the products in good yields and the synthesized compounds were purified by recrystallization. Coumarinyl pyrazolinyl thioamide derivatives 5a - 5q showed significant activity against Urease enzyme and also exhibited good antioxidant potential. The compound 3-(2-oxo-2H-chromen-3-yl)-5-phenyl-4,5-dihydro-1H-pyrazole-1-carbothioamide (5n) was found to be superior agent in the series with an IC 50  = 0.358 ± 0.017 μm compared to standard thiourea with an IC 50  = 4720 ± 174 μm. To undermine the binding mode of inhibition kinetic studies were performed for most potent derivative and it was found that compound 5n inhibits urease enzyme by non-competitive mode of inhibition. Molecular docking studies were carried out to delineate the binding affinity of the synthesized derivatives. © 2017 Wiley-VHCA AG, Zurich, Switzerland.

Isolation and characterization of a novel catalase-negative, urease-positive Campylobacter from cattle faeces

DEFF Research Database (Denmark)

Atabay, H.I.; Corry, J.E.L.; On, S.L.W.

1997-01-01

characteristics typical for Campylobacter species. However, they were unusual in that they produced urease and copious H2S in triple sugar iron (TSI) medium, but did not produce catalase. They did not grow aerobically. None of the strains grew on modified cefoperazone charcoal deoxycholate agar (m......CCDA). Macrorestriction profiles of chromosomal DNA were prepared for 15 strains using pulsed-field gel electrophoresis (PFGE). Twelve of 15 profiles were identical and all appeared to be closely related. These catalase-negative, urease-positive campylobacters (CNUPC) represent a group not previously reported...

Determination of some properties of free and immobilized urease from aspergillus fumigatus and its application in urea assay

International Nuclear Information System (INIS)

Tetiker, A.T.; Ertan, F.

2016-01-01

Urease enzyme was extracted from Apergillus fumigatus and immobilized in calcium alginate beads. The immobilization efficiency was calculated as 82.5 %. Optimum pH and temperature for free and immobilized enzymes were found to be 7.0 and 40 degree C, respectively. The immobilized urease had a better Km value but, catalytic efficiencies (kcat/Km) were very similar. Immobilized enzyme maintained 44% of its initial activity after 5 repeated use of enzyme. It was found that storage stability of immobilized enzyme was better than that of the free enzyme. Immobilized urease enzyme was used for the determination of urea amounts in animal feed. (author)

Synthesis, crystal structures, molecular docking and urease inhibition studies of Ni(II) and Cu(II) Schiff base complexes

Science.gov (United States)

Sangeeta, S.; Ahmad, K.; Noorussabah, N.; Bharti, S.; Mishra, M. K.; Sharma, S. R.; Choudhary, M.

2018-03-01

[Ni(L)2] 1 and [Cu(L)2] 2 [HL = 2-((E)-(2-methoxyphenylimino)methyl)-4,6-dichlorophenol] Schiff base complexes have been successfully synthesized and were characterized by FT-IR, UV-Vis, fluorescence spectroscopy and thermogravimetric analysis. The crystal structures of the two complexes were determined through X-ray crystallography. Its inhibitory activity against Helicobacter pylori urease was evaluated in vitro and showed strong inhibitory activity against H. pylori urease compared with acetohydroxamic acid (IC50 = 42.12 μmolL-1), which is a positive reference. A docking analysis using the AutoDock 4.0 program could explain the inhibitory activity of the complex against urease.

Immobilization of urease on grafted starch by radiation method

International Nuclear Information System (INIS)

Nguyenanh Dung; Nguyendinh Huyen

1995-01-01

The acrylamide was grafted by radiation onto starch which is a kind of polymeric biomaterial. The urease was immobilized on the grafted starch. Some experiments to observe the quantitative relationships between the percent graft and the activity of immobilized enzyme were determined. The enzyme activity was maintained by more than seven batch enzyme reactions. (author)

Mutational analysis of the major soybean UreF paralogue involved in urease activation

Science.gov (United States)

Polacco, Joe C.; Hyten, David L.; Medeiros-Silva, Mônica; Sleper, David A.; Bilyeu, Kristin D.

2011-01-01

The soybean genome duplicated ∼14 and 45 million years ago and has many paralogous genes, including those in urease activation (emplacement of Ni and CO2 in the active site). Activation requires the UreD and UreF proteins, each encoded by two paralogues. UreG, a third essential activation protein, is encoded by the single-copy Eu3, and eu3 mutants lack activity of both urease isozymes. eu2 has the same urease-negative phenotype, consistent with Eu2 being a single-copy gene, possibly encoding a Ni carrier. Unexpectedly, two eu2 alleles co-segregated with missense mutations in the chromosome 2 UreF paralogue (Ch02UreF), suggesting lack of expression/function of Ch14UreF. However, Ch02UreF and Ch14UreF transcripts accumulate at the same level. Further, it had been shown that expression of the Ch14UreF ORF complemented a fungal ureF mutant. A third, nonsense (Q2*) allelic mutant, eu2-c, exhibited 5- to 10-fold more residual urease activity than missense eu2-a or eu2-b, though eu2-c should lack all Ch02UreF protein. It is hypothesized that low-level activation by Ch14UreF is ‘spoiled’ by the altered missense Ch02UreF proteins (‘epistatic dominant-negative’). In agreement with active ‘spoiling’ by eu2-b-encoded Ch02UreF (G31D), eu2-b/eu2-c heterozygotes had less than half the urease activity of eu2-c/eu2-c siblings. Ch02UreF (G31D) could spoil activation by Chr14UreF because of higher affinity for the activation complex, or because Ch02UreF (G31D) is more abundant than Ch14UreF. Here, the latter is favoured, consistent with a reported in-frame AUG in the 5' leader of Chr14UreF transcript. Translational inhibition could represent a form of ‘functional divergence’ of duplicated genes. PMID:21430294

Increasing biopsy number and sampling from gastric body improve the sensitivity of rapid urease test in patients with peptic ulcer bleeding.

Science.gov (United States)

Lee, Tzong-Hsi; Lin, Chien-Chu; Chung, Chen-Shuan; Lin, Cheng-Kuan; Liang, Cheng-Chao; Tsai, Kuang-Chau

2015-02-01

Previous studies demonstrated that the sensitivity of rapid urease test (RUT) for diagnosis of Helicobacter pylori infection decreased during peptic ulcer bleeding. We designed this study and tried to find a better method to improve the detection rate of H. pylori infection at the same session of endoscopic diagnosis of peptic ulcer bleeding. We prospectively enrolled 116 patients with peptic ulcer bleeding. These patients received intravenous proton pump inhibitor and then received upper gastrointestinal endoscopy within 24 h after arrival. We took one piece of biopsy from gastric antrum (Group 1), four pieces from gastric antrum (Group 2), and one piece from the gastric body (Group 3) for three separate RUTs, respectively. (13)C-urease breath test was used as gold standard for diagnosis of H. pylori infection. There were 74 patients (64 %) with positive (13)C-urease breath test. Among these 74 patients, 45 patients had positive RUT (sensitivity: 61 %) in Group 1; 55 patients had positive RUT (sensitivity: 74 %) in Group 2; 54 patients had positive RUT (sensitivity: 73 %) in Group 3. There were significant differences between Group 1 and Group 2 (p = 0.02) and between Group 1 and Group 3 (p = 0.022). The sensitivity of RUT was 61 % during peptic ulcer bleeding. The sensitivity of RUT can be increased significantly by increased biopsy number from gastric antrum or biopsy from gastric body.

Synthesis, structures and Helicobacter pylori urease inhibitory activity of copper(II) complexes with tridentate aroylhydrazone ligands.

Science.gov (United States)

Pan, Lin; Wang, Cunfang; Yan, Kai; Zhao, Kedong; Sheng, Guihua; Zhu, Hailiang; Zhao, Xinlu; Qu, Dan; Niu, Fang; You, Zhonglu

2016-06-01

A series of new copper(II) complexes were prepared. They are [CuL(1)(NCS)] (1), [CuClL(1)]·CH3OH (2), [CuClL(2)]·CH3OH (3), [CuL(3)(NCS)]·CH3OH (4), [CuL(4)(NCS)]·0.4H2O (5), and [CuL(5)(bipy)] (6), where L(1), L(2), L(3) and L(4) are the deprotonated form of N'-(2-hydroxybenzylidene)-3-methylbenzohydrazide, 4-bromo-N'-(2-hydroxy-5-methoxybenzylidene)benzohydrazide, N'-(2-hydroxy-5-methoxybenzylidene)-3-methylbenzohydrazide and 2-chloro-N'-(2-hydroxy-5-methoxybenzylidene)benzohydrazide, respectively, L(5) is the dianionic form of N'-(2-hydroxybenzylidene)-3-methylbenzohydrazide, and bipy is 2,2'-bipyridine. The complexes were characterized by infrared and UV-Vis spectra and single crystal X-ray diffraction. The Cu atoms in complexes 1, 2, 3, 4 and 5 are coordinated by the NOO donor set of the aroylhydrazone ligands, and one Cl or thiocyanate N atom, forming square planar coordination. The Cu atom in complex 6 is in a square pyramidal coordination, with the NOO donor set of L(1), and one N atom of bipy defining the basal plane, and with the other N atom of bipy occupying the apical position. Complexes 1, 2, 3, 4 and 5 show effective urease inhibitory activities, with IC50 values of 5.14, 0.20, 4.06, 5.52 and 0.26μM, respectively. Complex 6 has very weak activity against urease, with IC50 value over 100μM. Molecular docking study of the complexes with the Helicobacter pylori urease was performed. The relationship between structures and urease inhibitory activities indicated that copper complexes with square planar coordination are better models for urease inhibition. Copyright © 2016 Elsevier Inc. All rights reserved.

Dynamic HypA zinc site is essential for acid viability and proper urease maturation in Helicobacter pylori.

Science.gov (United States)

Johnson, Ryan C; Hu, Heidi Q; Merrell, D Scott; Maroney, Michael J

2015-04-01

Helicobacter pylori requires urease activity in order to survive in the acid environment of the human stomach. Urease is regulated in part by nickelation, a process that requires the HypA protein, which is a putative nickel metallochaperone that is generally associated with hydrogenase maturation. However, in H. pylori, HypA plays a dual role. In addition to an N-terminal nickel binding site, HypA proteins also contain a structural zinc site that is coordinated by two rigorously conserved CXXC sequences, which in H. pylori are flanked by His residues. These structural Zn sites are known to be dynamic, converting from Zn(Cys)4 centers at pH 7.2 to Zn(Cys)2(His)2 centers at pH 6.3 in the presence of Ni(ii) ions. In this study, mutant strains of H. pylori that express zinc site variants of the HypA protein are used to show that the structural changes in the zinc site are important for the acid viability of the bacterium, and that a reduction in acid viability in these variants can be traced in large measure to deficient urease activity. This in turn leads to a model that connects the Zn(Cys)4 coordination to urease maturation.

Development of a large-scale HPLC-based purification for the urease from Staphylococcus leei and determination of subunit structure.

Science.gov (United States)

Jin, Ming; Rosario, Wildys; Watler, Elsie; Calhoun, David H

2004-03-01

Coagulase-positive Staphylococcus species, related to but distinct from the genetic homology group containing Staphylococcus cohnii, Staphylococcus xylosus, and Staphylococcus saphrophyticus, were isolated from biopsy material obtained from a cluster of patients in Korea suffering from gastritis. The prototype isolate, Staphylococcus leei, has high urease activity that is similar with respect to a low K(m) value and acid resistance of the urease found in the stomach adapted pathogen, Helicobacter pylori. S. leei is remarkably resistant to lysis and only a small fraction of the cells are broken using sonication, a French press, Niro homogenizer, or a Gaulin mill. In the present report, we describe an efficient cell lysis procedure for S. leei using three passes through a Dynomill with 0.5mm glass beads that results in lysis of more than 95% of the cells. We also developed an efficient and large-scale purification procedure for the S. leei urease using a BioCAD HPLC Workstation using Q-Sepharose, Poros HP2, Sephacryl S-300, and hydroxyapatite chromatography. The urease of S. leei was purified 98-fold to a specific activity of 731U/mg. The urease protein is composed of three subunits, alpha (65kDa), beta (21kDa), and gamma (12kDa), and in situ enzyme assay and molecular sieve chromatography indicate that multiple high molecular weight forms are present, including an apparent pentamer of 1:1:1 alphabetagamma-heterotrimers of 480kDa. This purification procedure was used to purify 16mg of enzyme from 120-liters of cell culture. This improved lysis and purification procedure will make it possible to obtain sufficient quantities of urease for use as an antigen in ELISA assays to carry out studies to determine the incidence and demographic prevalence of gastritis due to S. leei.

Estimating the effect of urease inhibitor on rice yield based on NDVI at key growth stages

Directory of Open Access Journals (Sweden)

Kailou LIU,Yazhen LI,Huiwen HU

2014-06-01

Full Text Available The effect of the urease inhibitor, N-(n-butyl thiophosphoric triamide (NBPT at a range of application rates on rice production was examined in a field experiment at Jinxian County, Jiangxi Province, China. The normalized difference vegetation index (NDVI was measured at key growth stages in both early and late rice. The results showed that the grain yield increased significantly when urea was applied with NBPT, with the highest yield observed at 1.00% NBPT (wt/wt. NDVI differed with the growth stage of rice; it remained steady from the heading to the filling stage. Rice yield could be predicted from the NDVI taken at key rice growing stages, with R2 ranging from 0.34 to 0.69 in early rice and 0.49 to 0.70 in late rice. The validation test showed that RMSE (t·hm-2 values were 0.77 and 0.87 in early and late rice, respectively. Therefore, it was feasible to estimate rice yield for different amounts of urease inhibitor using NDVI.

Chemical studies of launaea nudicaulis hook f. extracts with antioxidant and urease inhibitory activities

International Nuclear Information System (INIS)

Mansoor, F.; Anis, I.

2013-01-01

Summary: An activity guide isolation of Launaea nudicaulis Hook f, medicinal plant of Indo-Pak region has shown antioxidant potentials via its polar solvent soluble fractions while urease inhibition studies (in vitro) indicated compound 8 and 9 as a good urease inhibitors. Eight compounds have also been isolated for the first time from Launaea nudicaulis Hook f., namely, Scopoletin 1, lupeol 2, beta-amyrin 3, beta-sitosterol 3-O-beta-D-glucopyranoside 4, stigmasterol 3-O-beta-D-glucopyranoside 5, 6- hydroxy flavone 6, 7-methoxy flavone 7 and kaempferol 8, respectively. Their structures were elucidated by EI-MS, FABMS, 1H-NMR spectroscopic data. (author)

Acetohydroxamic Acid - A Competitive Inhibitor of Urease from Soybean “Glycine max”

Directory of Open Access Journals (Sweden)

Sandeep Kumar

2010-06-01

Full Text Available The acetohydroxamic acid (AHA, a potent inhibitor of urease, inhibits soybean urease competitively and reversibly. The I50 and Ki value for AHA were 900 microM and 0.053 mM, respectively at pH 7.0, 37 °C. The variation in pH over the pH 6 - 9 affected Ki and therefore binding of AHA in the active site. The affinity of AHA for the active site decreases with lowering of pH (below the pKa value of AHA i.e. 8.7. This behaviour is consistent with the deprotonated AHA acting as a nucleophile or the inhibitory species. The time-dependent inhibition studies were performed at two different concentrations of AHA and the biphasic kinetics was revealed with almost equal amplitudes (50% each for fast and slow phases. The values of rate constants were 0.1642 ± 0.0013 min -1 (fast phase; 0.0123±0.0012 min -1 (slow phase at 0.10 mM AHA and 0.2379±0.0017 min -1 (fast phase; 0.0153±0.0010 min -1 (slow phase at 0.15 mM AHA. These studies established the asymmetric nature of active sites, half being more reactive for AHA than the other half. The spectral studies showed a change in absorbance at the lambda wavelength max 414 nm, when urease was incubated with AHA, which was consistent with AHA binding to Ni2+ of active site.

Detection of Helicobacter pylori urease antigen in saliva in patients with different gastric H. pylori status.

Science.gov (United States)

El Khadir, Mounia; Alaoui Boukhris, Samia; Benajah, Dafr-Allah; El Rhazi, Karima; Ibrahimi, Sidi Adil; El Abkari, Mohamed; Harmouch, Taoufiq; Nejjari, Chakib; Mahmoud, Mustapha; Benlemlih, Mohamed; Bennani, Bahia

2016-07-01

Finding a simple, accurate, and noninvasive diagnosis method is a substantial challenge for the detection of Helicobacter pylori. The aim of the present study was to compare the presence of H. pylori urease antigen in saliva with the presence of this bacterium in gastric mucosa. Saliva samples and gastric biopsies were taken from 153 consenting Moroccan patients. Saliva samples were analyzed using an immunochromatographic test for urease antigen H. pylori detection. Thereafter, the gastric biopsies were analyzed by histology and polymerase chain reaction (PCR) to detect this bacterium. From a total of 153 recruited Moroccan patients, H. pylori was detected in 28 (18.30%), 87 (57.24%), and 69 (45.10%) cases by saliva test, histology, and PCR, respectively. A significant association was observed between the presence of H. pylori antigen in saliva and age. However, no association was found with sex, H. pylori virulence factors, gastric disease outcome, and density of the bacterium on the gastric mucosa. Considering that only 90 patients presented concordant results on H. pylori diagnosis (positive or negative) by both histology and PCR, the immunochromatographic test showed very low sensitivity (29.79%) and high specificity (90.70%). Of these two tests, the positive and negative predictive values were 77.78% and 54.17%, respectively. The accuracy of the test for salivary detection of urease antigen H. pylori was 58.89%. This study demonstrated a low detection rate of H. pylori antigens in saliva compared with the presence of this bacterium in gastric mucosa, suggesting that saliva cannot be used as a suitable sample for the diagnosis of H. pylori in our study population. Copyright © 2016. Published by Elsevier Taiwan LLC.

Enzyme and inhibition assay of urease by continuous monitoring of the ammonium formation based on capillary electrophoresis.

Science.gov (United States)

Liu, Xiaoxia; Yang, Jiqing; Sun, Shucheng; Guo, Liping; Yang, Li

2016-10-01

We present here an easy-to-operate and efficient method for enzyme and inhibition assays of urease, which is a widely distributed and important enzyme that catalyzes the hydrolysis of urea to ammonia and CO 2 . The assay was achieved by integrating CE technique and rapid on-line derivatization method, allowing us to continuously drive the sample to the capillary, thus to measure the amount of the product ammonia from the beginning to the end of the reaction. The method exhibits excellent repeatability with RSD as low as 2.5% for the initial reaction rate (n = 5), with the LOD of ammonia of 20 μM (S/N = 5). The enzyme activity as well as the inhibition of urease by Cu 2+ were investigated using the present method. The results show that Cu 2+ is a noncompetitive inhibitor on urease, in accordance with the result published in the literature. The enzyme activity and inhibition kinetic constants were obtained and were found to be consistent with the results of traditional off-line enzyme assays. Our study indicates that the present approach is a reliable and convenient method for analysis of the urease activity and inhibition kinetics by continuous on-line monitoring of the ammonium formation based on CE. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mechanisms of inhibition by fluoride of urease activities of cell suspensions and biofilms of Staphylococcus epidermidis, Streptococcus salivarius, Actinomyces naeslundii and of dental plaque.

Science.gov (United States)

Barboza-Silva, E; Castro, A C D; Marquis, R E

2005-12-01

Fluoride is known to be a potent inhibitor of bacterial ureases and can also act in the form of hydrofluoric acid as a transmembrane proton conductor to acidify the cytoplasm of intact cells with possible indirect, acid inhibition of urease. Our research objectives were to assess the inhibitory potencies of fluoride for three urease-positive bacteria commonly found in the mouth and to determine the relative importance of direct and indirect inhibition of ureases for overall inhibition of intact cells or biofilms. The experimental design involved intact bacteria in suspensions, mono-organism biofilms, cell extracts, and dental plaque. Standard enzymatic assays for ammonia production from urea were used. We found that ureolysis by cells in suspensions or mono-organism biofilms of Staphylococcus epidermidis, Streptococcus salivarius or Actinomyces naeslundii was inhibited by fluoride at plaque levels of 0.1-0.5 mm in a pH-dependent manner. The results of experiments with the organic weak acids indomethacin and capric acid, which do not directly inhibit urease enzyme, indicated that weak-acid effects leading to cytoplasmic acidification are also involved in fluoride inhibition. However, direct fluoride inhibition of urease appeared to be the major mechanism for reduction in ureolytic activity in acid environments. Results of experiments with freshly harvested supragingival dental plaque indicated responses to fluoride similar to those of S. salivarius with pH-dependent fluoride inhibition and both direct and indirect inhibition of urease. Fluoride can act to diminish alkali production from urea by oral bacteria through direct and indirect mechanisms.

The effect of urea with urease inhibitors and urea on yield and nitrate content in potato tubers

Directory of Open Access Journals (Sweden)

Karel Drápal

2013-01-01

Full Text Available The three-year field trial was established on two localities – Žabčice and Valečov in 2010–2012. Seven variants of nitrogen fertilization in four replications have been involved in this experiment – 100% of urea (U, 80% of urea, 60% of urea, 100% of UreaStabil (US, 80% of UreaStabil and 60% of UreaStabil, whilst 100% corresponded to 90 kg N.ha−1 after subtracting the content of Nmin in the soil, and the control variant without fertilization by mineral nitrogen. The two varieties with different lengths of vegetation periods have been chosen for the experiment – the early variety Karin and the mid-early variety Red Anna. In all cases, samples for the yield and qualitative analyses have been taken according to the phenological phase – the beginning of physiological maturity. The obtained results show that the highest average yield has been achieved in the variant of 100% of urea – 40.95 t. ha−1, the yield of this variant was statistically significantly higher than the yield of the other variants of fertilization (P < 0.05. Variants treated by urea without the urease inhibitor reached an average yield of 37.62 t.ha−1. However, this yield was not statistically significantly higher when comparing to the urea with the urease inhibitor (P > 0.05. In regard to localities, a relatively high average yield (44.58 t.ha−1 has been achieved on a characteristically potato-growing locality Valečov. This yield was statistically significantly higher than the one attained on the Žabčice locality (P < 0.05. In respect to varieties, the mid-early variety Red Anna attained a higher average yield (39.65 t. ha−1. Likewise, this yield was statistically significantly higher than the one of the early variety Karin (P < 0.05. The best year was 2012, in which the average yield of 38.73 t.ha−1 was achieved. This yield was statistically significantly higher than the yield of the year 2010 (P < 0.05. As far as nitrates are concerned, the

Soybean seed treatment with nickel improves biological nitrogen fixation and urease activity

Directory of Open Access Journals (Sweden)

José eLavres Junior

2016-05-01

Full Text Available Nickel (Ni is an essential micronutrient required for plants’ metabolism due to its role as a structural component of urease and hydrogenase, which in turn perform nitrogen (N metabolism in many legume species. Seed treatment with cobalt, molybdenum and Bradyrhizobium strains has been widely practiced to improve crops. Additionally, seed treatment together with Ni fertilization of soybean might improve the efficiency of biological nitrogen fixation (BNF, boosting grain dry matter yield and N content. The objective of this study was to evaluate the effect of soybean seed treatment with Ni rates (0, 45, 90,135, 180, 360 and 540 mg kg-1 on biological nitrogen fixation (BNF, directly by the 15N natural abundance method (δ15N‰ and by measurement of urease [E.C. 3.5.1.5] activity, as well as indirectly by nitrogenase (N-ase activity [E.C. 1.18.6.1]. Soybean plants (cultivar BMX Potência RR were grown in a sandy soil up to the R7 developmental stage (grain maturity, at which point the nutrient content in the leaves, chlorophyll content, urease and N-ase activities, Ni and N content in the grains, nodulation (at R1 - flowering stage, as well as the contribution of biological nitrogen fixation (δ15N ‰, were evaluated. The proportion of N derived from N2 fixation varied from 77 to 99% using the natural 15N abundance method and non-nodulating Panicum miliaceum and Phalaris canariensis as references. A Ni rate of 45 mg kg-1 increased BNF by 12% compared to the control. The increased N uptake in the grains was closely correlated with chlorophyll content in the leaves, urease and N-ase activities, as well as with nodulation. Grain dry matter yield and aerial part dry matter yield increased, respectively, by 84% and 51% in relation to the control plants at 45 mg kg-1 Ni via seed treatment. Despite, Ni concentration was increased with Ni-seed treatment, Ni rates higher than 135 mg kg-1 promoted negative effects on plant growth and yield. In these

Innovative approach for urease inhibition by Ficus carica extract-fabricated silver nanoparticles: An in vitro study.

Science.gov (United States)

Borase, Hemant P; Salunkhe, Rahul B; Patil, Chandrashekhar D; Suryawanshi, Rahul K; Salunke, Bipinchandra K; Wagh, Nilesh D; Patil, Satish V

2015-01-01

In the present study, a rapid, low-cost, and ecofriendly method of stable silver nanoparticles (AgNPs) synthesis using leaves extract of Ficus carica (F. carica), a plant with diverse metabolic consortium, is reported for the first time. An absorption peak at 422 nm in UV-Vis spectroscopy, a spherical shape with an average size of 21 nm in transmission electron microscopy, and crystalline nature in X-ray powder diffraction studies were observed for the synthesized AgNPs. Fourier transform infrared analysis indicated that proteins of F. carica might have a vital role in AgNP synthesis and stabilization. AgNPs were found to inhibit urease, a key enzyme responsible for the survival and pathogenesis of the bacterium, Helicobacter pylori. Inhibition of urease by AgNPs was monitored spectrophotometrically by the evaluation of ammonia release. The urease inhibition potential of AgNPs can be explored in the treatment of H. pylori by preparing novel combinations of standard drugs with AgNPs- or AgNPs-encapsulated drug molecules. © 2015 International Union of Biochemistry and Molecular Biology, Inc.

Activity and lifetime of urease immobilized using layer-by-layer nano self-assembly on silicon microchannels.

Science.gov (United States)

Forrest, Scott R; Elmore, Bill B; Palmer, James D

2005-01-01

Urease has been immobilized and layered onto the walls of manufactured silicon microchannels. Enzyme immobilization was performed using layer-by-layer nano self-assembly. Alternating layers of oppositely charged polyelectrolytes, with enzyme layers "encased" between them, were deposited onto the walls of the silicon microchannels. The polycations used were polyethylenimine (PEI), polydiallyldimethylammonium (PDDA), and polyallylamine (PAH). The polyanions used were polystyrenesulfonate (PSS) and polyvinylsulfate (PVS). The activity of the immobilized enzyme was tested by pumping a 1 g/L urea solution through the microchannels at various flow rates. Effluent concentration was measured using an ultraviolet/visible spectrometer by monitoring the absorbance of a pH sensitive dye. The architecture of PEI/PSS/PEI/urease/PEI with single and multiple layers of enzyme demonstrated superior performance over the PDDA and PAH architectures. The precursor layer of PEI/PSS demonstrably improved the performance of the reactor. Conversion rates of 70% were achieved at a residence time of 26 s, on d 1 of operation, and >50% at 51 s, on d 15 with a six-layer PEI/urease architecture.

Analysis of a Soluble (UreD:UreF:UreG)2 Accessory Protein Complex and its Interactions with Klebsiella aerogenes Urease by Mass Spectrometry

Science.gov (United States)

Farrugia, Mark A.; Han, Linjie; Zhong, Yueyang; Boer, Jodi L.; Ruotolo, Brandon T.; Hausinger, Robert P.

2013-01-01

Maturation of the nickel-containing urease of Klebsiella aerogenes is facilitated by the UreD, UreF, and UreG accessory proteins along with the UreE metallo-chaperone. A fusion of the maltose binding protein and UreD (MBP-UreD) was co-isolated with UreF and UreG in a soluble complex possessing a (MBP-UreD:UreF:UreG)2 quaternary structure. Within this complex a UreF:UreF interaction was identified by chemical cross-linking of the amino termini of its two UreF protomers, as shown by mass spectrometry of tryptic peptides. A pre-activation complex was formed by the interaction of (MBP-UreD:UreF:UreG)2 and urease. Mass spectrometry of intact protein species revealed a pathway for synthesis of the urease pre-activation complex in which individual hetero-trimer units of the (MBP-UreD:UreF:UreG)2 complex bind to urease. Together, these data provide important new insights into the structures of protein complexes associated with urease activation. PMID:23797863

Azomethines, isoxazole, N-substituted pyrazoles and pyrimidine containing curcumin derivatives: Urease inhibition and molecular modeling studies.

Science.gov (United States)

Ahmed, Mahmood; Qadir, Muhammad Abdul; Hameed, Abdul; Arshad, Muhammad Nadeem; Asiri, Abdullah M; Muddassar, Muhammad

2017-08-19

Curcumin has shown large number of pharmacological properties against different phenotypes of various disease models. Different synthetic routes have been employed to develop its various derivatives for diverse biological functions. In this study, curcumin derived azomethine, isoxazole, pyrimidines and N-substituted pyrazoles were synthesized to investigate their urease enzyme inhibition. The structures of newly synthesized compounds were described by IR, MS, 1 H NMR and 13 C NMR spectral data. Urease enzyme inhibition was evaluated through in vitro assays in which compound 8b was found to be the most potent (IC 50  = 2.44 ± 0.07 μM) among the tested compounds. The compounds with diazine ring system except the 4d showed better urease inhibition (IC 50  = 11.43 ± 0.21-19.63 ± 0.28 μM) than the standard urease inhibitor thiourea (IC 50  = 22.61 ± 0.23 μM). Similarly enzyme kinetics data revealed that compounds 3c-3e and 8b were competitive inhibitors with Ki values of 20.0, 19.87, 20.23 and 19.11 μM respectively while the compounds 4b, 4c and 4e were mixed type of inhibitors with Ki values 6.72, 19.69 and 6.72 μM respectively. Molecular docking studies were also performed to identify the plausible binding modes of the most active compounds. Copyright © 2017 Elsevier Inc. All rights reserved.

Soil phosphatase and urease activities impacted by cropping systems and water management

Science.gov (United States)

Soil enzymes can play an important role in nutrient availability to plants. Consequently, soil enzyme measurements can provide useful information on soil fertility for crop production. We examined the impact of cropping system and water management on phosphatase, urease, and microbial biomass C in s...

Amino Acid Composition, Urease Activity and Trypsin Inhibitor Activity after Toasting of Soybean in Thick and Thin Layer

OpenAIRE

Krička, Tajana; Jurišić, Vanja; Voća, Neven; Ćurić, Duška; Brlek Savić, Tea; Matin, Ana

2009-01-01

The objective of this study was to determine amino acid content, urease activity and trypsin inhibitor activity in soybean grain for polygastric animals’ feed aft er toasting with the aim to introduce thick layer in toasting technology. Hence, soybean was toasted both in thick and thin layer at 130 oC during 10 minutes. In order to properly monitor the technological process of soybean thermal processing, it was necessary to study crude protein content, urease activity, trypsin inhibitor activ...

Synthesis of 2-acylated and sulfonated 4-hydroxycoumarins: In vitro urease inhibition and molecular docking studies.

Science.gov (United States)

Rashid, Umer; Rahim, Fazal; Taha, Muhammad; Arshad, Muhammad; Ullah, Hayat; Mahmood, Tariq; Ali, Muhammad

2016-06-01

Sixteen 4-hydroxycoumarin derivatives were synthesized, characterized through EI-MS and (1)H NMR and screened for urease inhibitory potential. Three compounds exhibited better urease inhibition than the standard inhibitor thiourea (IC50=21±0.11μM) while other four compounds exhibited good to moderate inhibition with IC50 values between 29.45±1.1μM and 69.53±0.9μM. Structure activity relationship was established on the basis of molecular docking studies, which helped to predict the binding interactions of the most active compounds. Copyright © 2016 Elsevier Inc. All rights reserved.

Carbon Nanotubes and Algal Polysaccharides To Enhance the Enzymatic Properties of Urease in Lipid Langmuir-Blodgett Films.

Science.gov (United States)

Rodrigues, Raul T; Morais, Paulo V; Nordi, Cristina S F; Schöning, Michael J; Siqueira, José R; Caseli, Luciano

2018-03-06

Algal polysaccharides (extracellular polysaccharides) and carbon nanotubes (CNTs) were adsorbed on dioctadecyldimethylammonium bromide Langmuir monolayers to serve as a matrix for the incorporation of urease. The physicochemical properties of the supramolecular system as a monolayer at the air-water interface were investigated by surface pressure-area isotherms, surface potential-area isotherms, interfacial shear rheology, vibrational spectroscopy, and Brewster angle microscopy. The floating monolayers were transferred to hydrophilic solid supports, quartz, mica, or capacitive electrolyte-insulator-semiconductor (EIS) devices, through the Langmuir-Blodgett (LB) technique, forming mixed films, which were investigated by quartz crystal microbalance, fluorescence spectroscopy, and field emission gun scanning electron microscopy. The enzyme activity was studied with UV-vis spectroscopy, and the feasibility of the thin film as a urea sensor was essayed in an EIS sensor device. The presence of CNT in the enzyme-lipid LB film not only tuned the catalytic activity of urease but also helped to conserve its enzyme activity. Viability as a urease sensor was demonstrated with capacitance-voltage and constant capacitance measurements, exhibiting regular and distinctive output signals over all concentrations used in this work. These results are related to the synergism between the compounds on the active layer, leading to a surface morphology that allowed fast analyte diffusion owing to an adequate molecular accommodation, which also preserved the urease activity. This work demonstrates the feasibility of employing LB films composed of lipids, CNT, algal polysaccharides, and enzymes as EIS devices for biosensing applications.

Study of antioxidant, anti-protease and anti-urease potential of schiff bases of acetophenone with different amines

International Nuclear Information System (INIS)

Ahmed, D.; Mir, H.

2014-01-01

Seven acetophenone-derived Schiff bases were synthesized with different amines including 2-aminobenzoic acid (HL1), 4-aminobenzoic acid (HL2), 2-naphthylamine (HL3), phenylhydrazine (HL4), 1,2-ethanediamine (HL5), 1,2-diaminobenzene (HL6) and 1,4-diaminobenzene (HL7), and were subjected to various assays including FRAP (ferric reducing antioxidant power), DPPH (1,1-diphenyl-2-picrylhydrazyl), phosphomolybdate, reducing power, and lipid peroxidation inhibition. They were also evaluated for protease and urease inhibitory activities. Based on the results, structure-activity relationship (SAR) was determined. Only two bases, HL1 and HL4, exhibited antioxidant or free radical scavenging activity in DPPH assay. HL4 was most potent (IC50 15 micro g/mL), while HL1 was only slightly active. As HL4 was the only base with hydrogen bonded to nitrogen, most probably it involves hydrogen transfer (HT) mechanism. All the bases exhibited a range of antioxidant activity in assays involving electron transfer (ET). In the reducing power assay, HL5, HL6 and HL7 showed considerable potential while in FRAP assay, HL7 was most active followed by HL3. In phosphomolybdate assay, HL6 had the highest potency followed by HL7, while HL4 and HL3 also displayed good activity. All the bases showed moderate to high lipid peroxidation inhibitory activity. HL7 exhibited highest protease inhibitory activity (EC50 43.9 mu g/mL) followed by HL6 (EC/sub 50/ 52 mu g/mL). HL4 and HL5 did not show protease inhibitory activity at all. HL2 was most potent in inhibiting urease activity (EC50 29.91 mu g/mL). HL5 and HL6 showed moderate activity. The study showed how variation in structures of Schiff bases alters their antioxidant and anti-enzymatic activities. (author)

Molecular landscape of the interaction between the urease accessory proteins UreE and UreG.

Science.gov (United States)

Merloni, Anna; Dobrovolska, Olena; Zambelli, Barbara; Agostini, Federico; Bazzani, Micaela; Musiani, Francesco; Ciurli, Stefano

2014-09-01

Urease, the most efficient enzyme so far discovered, depends on the presence of nickel ions in the catalytic site for its activity. The transformation of inactive apo-urease into active holo-urease requires the insertion of two Ni(II) ions in the substrate binding site, a process that involves the interaction of four accessory proteins named UreD, UreF, UreG and UreE. This study, carried out using calorimetric and NMR-based structural analysis, is focused on the interaction between UreE and UreG from Sporosarcina pasteurii, a highly ureolytic bacterium. Isothermal calorimetric protein-protein titrations revealed the occurrence of a binding event between SpUreE and SpUreG, entailing two independent steps with positive cooperativity (Kd1=42±9μM; Kd2=1.7±0.3μM). This was interpreted as indicating the formation of the (UreE)2(UreG)2 hetero-oligomer upon binding of two UreG monomers onto the pre-formed UreE dimer. The molecular details of this interaction were elucidated using high-resolution NMR spectroscopy. The occurrence of SpUreE chemical shift perturbations upon addition of SpUreG was investigated and analyzed to establish the protein-protein interaction site. The latter appears to involve the Ni(II) binding site as well as mobile portions on the C-terminal and the N-terminal domains. Docking calculations based on the information obtained from NMR provided a structural basis for the protein-protein contact site. The high sequence and structural similarity within these protein classes suggests a generality of the interaction mode among homologous proteins. The implications of these results on the molecular details of the urease activation process are considered and analyzed. Copyright © 2014 Elsevier B.V. All rights reserved.

2-nitrobenzohydrazide as a potent urease inhibitor: synthesis, characterization and single crystal x-ray diffraction analysis

International Nuclear Information System (INIS)

Abbas, N.; Khan, I.; Hameed, S.; Batool, S.

2018-01-01

2-Nitrobenzohydrazide was efficiently synthesized in two steps by the esterification of 2-nitrobenzoic acid followed by the treatment with hydrazine hydrate in methanol. The structure of 2-nitrobenzohydrazide was established by modern spectro-analytical techniques including FTIR, 1H and 13C-NMR spectroscopy and unequivocally confirmed by single crystal X-ray diffraction data. 2-Nitrobenzohydrazide crystallized in orthorhombic space group P 21 21 21 with unit cell dimensions a = 4.9764(4) Å, b = 12.5280 (3) Å, c = 12.8512(1) Å, α = β = γ = 90°. A combination of N‒H…N and N‒H…O hydrogen bonds stabilized the crystal packing of 3. The synthesized compound 3 was assessed as urease inhibitor against Jack bean urease and the results revealed good inhibitory potency with an IC50 value of 4.25 ± 0.08 µM. This inhibition strength was 5-fold higher compared to the reference inhibitor thiourea (IC50 = 21.00 ± 0.11 µM). The molecular docking studies of the synthesized inhibitor 3 inside the active pocket of urease revealed several important binding interactions. (author)

GC-MS Analysis of Fixed Oil from Nelumbo nucifera Gaertn Seeds: Evaluation of Antimicrobial, Antileishmanial and Urease Inhibitory Activities

International Nuclear Information System (INIS)

Shahnaz, A.; Khan, H.; Shah, A.; Khan, N.M.

2016-01-01

In the present study, chemical composition of fixed oil (NnFO) obtained from Nelumbo nucifera seeds was determined by GC-MS analysis which revealed the presence of 39 compounds mainly comprised of 20.8 % keto fatty acids with high content of methyl ester of palmitic acid (13.59 %) and methyl ester of 9-oxo-nonanoic acid (11.89 %). The other major constituents identified were; fumaric acid-3-methylbut-3-enyl nonyl ester, 2-decenal and methyl ester of 9E-octadecenoic acid as 6.45 %, 5.09 %, 5.06 %, respectively. NnFO along with other fractions were tested for in vitro antimicrobial, antileishmanial and urease inhibitory assays. NnFO showed weak antibacterial activities against the tested bacteria while promising antifungal effect against Candida albicans (68 %), Candida glaberata (65 %) and Aspergillus flavus (64 %). NnFO showed strong antileishmanial activity with IC50 = 7.34 ±0.72 as compared to reference drug (5.1± 0.29) probably due to the presence of keto-ene derivatives. NnFO showed weak urease inhibitory activity while the ethyl acetate fraction (N3) strongly inhibited both J.B. urease (IC50= 21.45 %) and B.P. urease (IC50= 28.65%) respectively. In conclusion, N. nucifera seeds fixed oil possess promising therapeutic potential as a new antifungal and antileishmanial agent. (author)

Immunologic properties and therapeutic efficacy of a multivalent epitope-based vaccine against four Helicobacter pylori adhesins (urease, Lpp20, HpaA, and CagL) in Mongolian gerbils.

Science.gov (United States)

Guo, Le; Yin, Runting; Xu, Guangxian; Gong, Xiaojuan; Chang, Zisong; Hong, Dantong; Liu, Hongpeng; Ding, Shuqin; Han, Xuebo; Li, Yuan; Tang, Feng; Liu, Kunmei

2017-12-01

Therapeutic vaccination is a desirable alternative for controlling Helicobacter pylori (H. pylori) infection. Attachment to the gastric mucosa is the first step in establishing bacterial colonization, and adhesins, which are on the surface of H. pylori, play a pivotal role in binding to human gastric mucosa. In the present study, we constructed a multivalent epitope-based vaccine named CFAdE with seven carefully selected antigenic fragments from four H. pylori adhesins (urease, Lpp20, HpaA and CagL). The specificity, immunogenicity and ability to produce neutralizing antibodies of CFAdE were evaluated in BALB/c mice. After that, its therapeutic efficacy and protective immune mechanisms were explored in H. pylori-infected Mongolian gerbils. The results indicated that CFAdE could induce comparatively high levels of specific antibodies against urease, Lpp20, HpaA and CagL. Additionally, oral therapeutic immunization with CFAdE plus polysaccharide adjuvant (PA) significantly decreased H. pylori colonization compared with oral immunization with urease plus PA, and the protection was correlated with IgG and sIgA antibody and antigen-specific CD4 + T cells. This study indicated that the multivalent epitope-based vaccine, which targeted multiple adhesins in adherence of H. pylori to the gastric mucosa, is more effective than the univalent vaccine targeting urease only. This multivalent epitope-based vaccine may be a promising therapeutic candidate vaccine against H. pylori infection. © 2017 John Wiley & Sons Ltd.

Impact of urease inhibitors on utilization efficiency of N-urea in rice paddy

International Nuclear Information System (INIS)

Chen Wei; Lu Wanfang

1998-01-01

Urea applied to the paddy field rapidly released ammonium (NH 4 + ) through hydrolysis. The released NH 4 + -N was usually at peak two days after the application. The peak was found to be lower and delay one day when a mixture of urea and urease inhibitors was applied. Based on tracing of 15 N in the urea used, the two urease inhibitors, phenylphosphordiamidate (PPD) and N-(N-butyl) thiophosphoric triamide (NBPT), were found to enhance the efficiency of urea utilization by rice plants due to more absorption and also stimulate rice growth. The grain yields in the treatments applied with the mixture containing PPD or NBPT were higher, particularly at high N level, than that in the treatment applied with urea only. However, the urea inhibitor, hydroquinone (HQ), displayed far less effect than PPD and NBPT in the experiment. The application of rice straw was found to decrease the absorption of rice plants to N in urea but increase its residue in the soil

Inhibition of Helicobacter pylori and Associated Urease by Oregano and Cranberry Phytochemical Synergies

Science.gov (United States)

Lin, Y. T.; Kwon, Y. I.; Labbe, R. G.; Shetty, K.

2005-01-01

Ulcer-associated dyspepsia is caused by infection with Helicobacter pylori. H. pylori is linked to a majority of peptic ulcers. Antibiotic treatment does not always inhibit or kill H. pylori with potential for antibiotic resistance. The objective of this study was to determine the potential for using phenolic phytochemical extracts to inhibit H. pylori in a laboratory medium. Our approach involved the development of a specific phenolic profile with optimization of different ratios of extract mixtures from oregano and cranberry. Subsequently, antimicrobial activity and antimicrobial-linked urease inhibition ability were evaluated. The results indicated that the antimicrobial activity was greater in extract mixtures than in individual extracts of each species. The results also indicate that the synergistic contribution of oregano and cranberry phenolics may be more important for inhibition than any species-specific phenolic concentration. Further, based on plate assay, the likely mode of action may be through urease inhibition and disruption of energy production by inhibition of proline dehydrogenase at the plasma membrane. PMID:16332847

Synthesis, Density Functional Theory (DFT), Urease Inhibition and Antimicrobial Activities of 5-Aryl Thiophenes Bearing Sulphonylacetamide Moieties.

Science.gov (United States)

Noreen, Mnaza; Rasool, Nasir; Gull, Yasmeen; Zubair, Muhammad; Mahmood, Tariq; Ayub, Khurshid; Nasim, Faiz-Ul-Hassan; Yaqoob, Asma; Zia-Ul-Haq, Muhammad; de Feo, Vincenzo

2015-11-05

A variety of novel 5-aryl thiophenes 4a-g containing sulphonylacetamide (sulfacetamide) groups were synthesized in appreciable yields via Pd[0] Suzuki cross coupling reactions. The structures of these newly synthesized compounds were determined using spectral data and elemental analysis. Density functional theory (DFT) studies were performed using the B3LYP/6-31G (d, p) basis set to gain insight into their structural properties. Frontier molecular orbital (FMOs) analysis of all compounds 4a-g was computed at the same level of theory to get an idea about their kinetic stability. The molecular electrostatic potential (MEP) mapping over the entire stabilized geometries of the molecules indicated the reactive sites. First hyperpolarizability analysis (nonlinear optical response) were simulated at the B3LYP/6-31G (d, p) level of theory as well. The compounds were further evaluated for their promising antibacterial and anti-urease activities. In this case, the antibacterial activities were estimated by the agar well diffusion method, whereas the anti-urease activities of these compounds were determined using the indophenol method by quantifying the evolved ammonia produced. The results revealed that all the sulfacetamide derivatives displayed antibacterial activity against Bacillus subtiles, Escherichia coli, Staphylococcus aureus, Shigella dysenteriae, Salmonella typhae, Pseudomonas aeruginosa at various concentrations. Furthermore, the compound 4g N-((5-(4-chlorophenyl)thiophen-2-yl)sulfonyl) acetamide showed excellent urease inhibition with percentage inhibition activity ~46.23 ± 0.11 at 15 µg/mL with IC50 17.1 µg/mL. Moreover, some other compounds 4a-f also exhibited very good inhibition against urease enzyme.

Biochemical and genetic analyses of the oomycete Pythium insidiosum provide new insights into clinical identification and urease-based evolution of metabolism-related traits

Directory of Open Access Journals (Sweden)

Theerapong Krajaejun

2018-06-01

Full Text Available The oomycete microorganism, Pythium insidiosum, causes the life-threatening infectious condition, pythiosis, in humans and animals worldwide. Affected individuals typically endure surgical removal of the infected organ(s. Detection of P. insidiosum by the established microbiological, immunological, or molecular methods is not feasible in non-reference laboratories, resulting in delayed diagnosis. Biochemical assays have been used to characterize P. insidiosum, some of which could aid in the clinical identification of this organism. Although hydrolysis of maltose and sucrose has been proposed as the key biochemical feature useful in discriminating P. insidiosum from other oomycetes and fungi, this technique requires a more rigorous evaluation involving a wider selection of P. insidiosum strains. Here, we evaluated 10 routinely available biochemical assays for characterization of 26 P. insidiosum strains, isolated from different hosts and geographic origins. Initial assessment revealed diverse biochemical characteristics across the P. insidiosum strains tested. Failure to hydrolyze sugars is observed, especially in slow-growing strains. Because hydrolysis of maltose and sucrose varied among different strains, use of the biochemical assays for identification of P. insidiosum should be cautioned. The ability of P. insidiosum to hydrolyze urea is our focus, because this metabolic process relies on the enzyme urease, an important virulence factor of other pathogens. The ability to hydrolyze urea varied among P. insidiosum strains and was not associated with growth rates. Genome analyses demonstrated that urease- and urease accessory protein-encoding genes are present in both urea-hydrolyzing and non-urea-hydrolyzing strains of P. insidiosum. Urease genes are phylogenetically conserved in P. insidiosum and related oomycetes, while the presence of urease accessory protein-encoding genes is markedly diverse in these organisms. In summary, we dissected

Hibiscus sabdariffa L. and Its Bioactive Constituents Exhibit Antiviral Activity against HSV-2 and Anti-enzymatic Properties against Urease by an ESI-MS Based Assay.

Science.gov (United States)

Hassan, Sherif T S; Švajdlenka, Emil; Berchová-Bímová, Kateřina

2017-04-30

For decades, Hibiscus sabdariffa L. and its phytochemicals have been shown to possess a wide range of pharmacologic properties. In this study, aqueous extract of Hibiscus sabdariffa (AEHS) and its bioactive constituent protocatechuic acid (PCA), have been evaluated in vitro for their antiviral activity against HSV-2 clinical isolates and anti-enzymatic activity against urease. Antiherpetic activity was evaluated by the titer reduction assay in infected Vero cells, and cytotoxicity was evaluated by the neutral red dye-uptake method. Anti-urease activity was determined by a developed Electrospray Ionization-Mass Spectrometry (ESI-MS)-based assay. PCA showed potent anti-HSV-2 activity compared with that of acyclovir, with EC 50 values of 0.92 and 1.43 µg∙mL -1 , respectively, and selectivity indices > 217 and > 140, respectively. For the first time, AEHS was shown to exert anti-urease inhibition activity, with an IC 50 value of 82.4 µg∙mL -1 . This, combined with its safety, could facilitate its use in practical applications as a natural urease inhibitor. Our results present Hibiscus sabdariffa L. and its bioactive compound PCA as potential therapeutic agents in the treatment of HSV-2 infection and the treatment of diseases caused by urease-producing bacteria.

Hibiscus sabdariffa L. and Its Bioactive Constituents Exhibit Antiviral Activity against HSV-2 and Anti-enzymatic Properties against Urease by an ESI-MS Based Assay

Directory of Open Access Journals (Sweden)

Sherif T. S. Hassan

2017-04-01

Full Text Available For decades, Hibiscus sabdariffa L. and its phytochemicals have been shown to possess a wide range of pharmacologic properties. In this study, aqueous extract of Hibiscus sabdariffa (AEHS and its bioactive constituent protocatechuic acid (PCA, have been evaluated in vitro for their antiviral activity against HSV-2 clinical isolates and anti-enzymatic activity against urease. Antiherpetic activity was evaluated by the titer reduction assay in infected Vero cells, and cytotoxicity was evaluated by the neutral red dye-uptake method. Anti-urease activity was determined by a developed Electrospray Ionization-Mass Spectrometry (ESI-MS-based assay. PCA showed potent anti-HSV-2 activity compared with that of acyclovir, with EC50 values of 0.92 and 1.43 µg∙mL−1, respectively, and selectivity indices > 217 and > 140, respectively. For the first time, AEHS was shown to exert anti-urease inhibition activity, with an IC50 value of 82.4 µg∙mL−1. This, combined with its safety, could facilitate its use in practical applications as a natural urease inhibitor. Our results present Hibiscus sabdariffa L. and its bioactive compound PCA as potential therapeutic agents in the treatment of HSV-2 infection and the treatment of diseases caused by urease-producing bacteria.

A newly constructed primer pair for the PCR amplification, cloning and sequencing of the flagellin (flaA) gene from isolatesof urease-negative Campylobacter lari.

Science.gov (United States)

Sekizuka, Tsuyoshi; Yokoi, Taeko; Murayama, Ohoshi; Millar, B Cherie; Moore, Johne; Matsuda, Motoo

2005-08-01

A newly constructed primer pair (lari-Af/lari-Ar) designed to generate a product of the flagellin (flaA) gene for urease-negative Campylobacter lari produced a PCR amplicon of about 1700 bp for 16 isolates from 7 seagulls, 5 humans, 3 food animals and one mussel in Japan and Northern Ireland. Nucleotide sequencing and alignments of the flaA amplicons from these isolates demonstrated that the deduced amino acid sequences of the possible open reading frame were 564-572 amino acid residues in length with calculated molecular weights of 58,804 to 59,463. The deduced amino acid sequence similarity analysis strongly suggested that the ORF of the flaA from the 16 isolates showed 70-75% sequence similarities to those of Campylobacter jejuni isolates. The approximate Mr of the flagellin purified from some of the isolates of urease-negative C. lari was estimated to range from 59.6 to 61.8 kDa. Thus, flagellin from the isolates of urease-negative C. lari was shown for the first time to have a molecular size similar to those of C. jejuni and Campylobacter coli isolates, but to be different from the shorter flaA and smaller flagellin of urease-positive thermophilic Campylobacter (UPTC) isolates. Flagellins from C. lari spp., consisting of the two representative taxa of urease-negative C. lari and UPTC, thus show genotypic and phenotypic diversity.

Influence of exogenous urea on photosynthetic pigments, (14)CO 2 uptake, and urease activity in Elodea densa-environmental implications.

Science.gov (United States)

Maleva, Maria; Borisova, Galina; Chukina, Nadezda; Nekrasova, Galina; Prasad, M N V

2013-09-01

This paper analyzes the effect of exogenous urea in increased concentration gradient (0, 100, 500 and 1,000 mg L(-1)) on photosynthetic pigments (measured spectrophotometrically), uptake of (14)CO2 (using radioisotope), and urease activity (by measuring ammonia with Nessler's reagent) in leaves of Elodea densa Planch. We have observed that low concentration of urea (100 mg L(-1)) stimulates the accumulation of photosynthetic pigments and intensifies photosynthesis in E. densa, whereas high concentration (1,000 mg L(-1)) suppresses these processes. Urease activity increased by approximately 2.7 and 8 fold when exogenous urea concentrations were 100 and 500 mg L(-1), respectively. However, exogenous urea in high concentration (1,000 mg L(-1)) decreased urease activity by 1.5 fold compared to the control. The necessity of mitigating urea and other nitrogen-containing compounds (NH3 from urea) in water bodies has been discussed with emphasis on the potential for phytoremediation of urea using common water weed viz. E. densa.

Synthesis of chiral pyrazolo[4,3-e][1,2,4]triazine sulfonamides with tyrosinase and urease inhibitory activity.

Science.gov (United States)

Mojzych, Mariusz; Tarasiuk, Paweł; Kotwica-Mojzych, Katarzyna; Rafiq, Muhammad; Seo, Sung-Yum; Nicewicz, Michał; Fornal, Emilia

2017-12-01

A new series of sulfonamide derivatives of pyrazolo[4,3-e][1,2,4]triazine with chiral amino group has been synthesized and characterized. The compounds were tested for their tyrosinase and urease inhibitory activity. Evaluation of prepared derivatives demonstrated that compounds (8b) and (8j) are most potent mushroom tyrosinase inhibitors whereas all of the obtained compounds showed higher urease inhibitory activity than the standard thiourea. The compounds (8a), (8f) and (8i) exhibited excellent enzyme inhibitory activity with IC 50 0.037, 0.044 and 0.042 μM, respectively, while IC 50 of thiourea is 20.9 μM.

Effect of propolis in gastric disorders: inhibition studies on the growth of Helicobacter pylori and production of its urease.

Science.gov (United States)

Baltas, Nimet; Karaoglu, Sengul Alpay; Tarakci, Cemre; Kolayli, Sevgi

2016-01-01

There is considerable interest in alternative approaches to inhibit Helicobacter pylori (H. pylori) and thus treat many stomach diseases. Propolis is a pharmaceutical mixture containing many natural bioactive substances. The aim of this study was to use propolis samples to treat H. pylori. The anti-H. pylori and anti-urease activities of 15 different ethanolic propolis extracts (EPEs) were tested. The total phenolic contents and total flavonoid contents of the EPE were also measured. The agar-well diffusion assay was carried out on H. pylori strain J99 and the inhibition zones were measured and compared with standards. All propolis extracts showed high inhibition of H. pylori J99, with inhibition diameters ranging from 31.0 to 47.0 mm. Helicobacter pylori urease inhibitory activity was measured using the phenol-hypochlorite assay; all EPEs showed significant inhibition against the enzyme, with inhibition concentrations (IC 50 ; mg/mL) ranging from 0.260 to 1.525 mg/mL. The degree of inhibition was related to the phenolic content of the EPE. In conclusion, propolis extract was found to be a good inhibitor that can be used in H. pylori treatment to improve human health.

Development and Characterization of a Camelid Single Domain Antibody-Urease Conjugate That Targets Vascular Endothelial Growth Factor Receptor 2.

Science.gov (United States)

Tian, Baomin; Wong, Wah Yau; Uger, Marni D; Wisniewski, Pawel; Chao, Heman

2017-01-01

Angiogenesis is the process of new blood vessel formation and is essential for a tumor to grow beyond a certain size. Tumors secrete the pro-angiogenic factor vascular endothelial growth factor, which acts upon local endothelial cells by binding to vascular endothelial growth factor receptors (VEGFRs). In this study, we describe the development and characterization of V21-DOS47, an immunoconjugate that targets VEGFR2. V21-DOS47 is composed of a camelid single domain anti-VEGFR2 antibody (V21) and the enzyme urease. The conjugate specifically binds to VEGFR2 and urease converts endogenous urea into ammonia, which is toxic to tumor cells. Previously, we developed a similar antibody-urease conjugate, L-DOS47, which is currently in clinical trials for non-small cell lung cancer. Although V21-DOS47 was designed from parameters learned from the generation of L-DOS47, additional optimization was required to produce V21-DOS47. In this study, we describe the expression and purification of two versions of the V21 antibody: V21H1 and V21H4. Each was conjugated to urease using a different chemical cross-linker. The conjugates were characterized by a panel of analytical techniques, including SDS-PAGE, size exclusion chromatography, Western blotting, and LC-MS E peptide mapping. Binding characteristics were determined by ELISA and flow cytometry assays. To improve the stability of the conjugates at physiologic pH, the pIs of the V21 antibodies were adjusted by adding several amino acid residues to the C-terminus. For V21H4, a terminal cysteine was also added for use in the conjugation chemistry. The modified V21 antibodies were expressed in the E. coli BL21 (DE3) pT7 system. V21H1 was conjugated to urease using the heterobifunctional cross-linker succinimidyl-[( N -maleimidopropionamido)-diethyleneglycol] ester (SM(PEG) 2 ), which targets lysine resides in the antibody. V21H4 was conjugated to urease using the homobifunctional cross-linker, 1,8-bis(maleimido)diethylene glycol

Development and Characterization of a Camelid Single Domain Antibody–Urease Conjugate That Targets Vascular Endothelial Growth Factor Receptor 2

Directory of Open Access Journals (Sweden)

Baomin Tian

2017-08-01

Full Text Available Angiogenesis is the process of new blood vessel formation and is essential for a tumor to grow beyond a certain size. Tumors secrete the pro-angiogenic factor vascular endothelial growth factor, which acts upon local endothelial cells by binding to vascular endothelial growth factor receptors (VEGFRs. In this study, we describe the development and characterization of V21-DOS47, an immunoconjugate that targets VEGFR2. V21-DOS47 is composed of a camelid single domain anti-VEGFR2 antibody (V21 and the enzyme urease. The conjugate specifically binds to VEGFR2 and urease converts endogenous urea into ammonia, which is toxic to tumor cells. Previously, we developed a similar antibody–urease conjugate, L-DOS47, which is currently in clinical trials for non-small cell lung cancer. Although V21-DOS47 was designed from parameters learned from the generation of L-DOS47, additional optimization was required to produce V21-DOS47. In this study, we describe the expression and purification of two versions of the V21 antibody: V21H1 and V21H4. Each was conjugated to urease using a different chemical cross-linker. The conjugates were characterized by a panel of analytical techniques, including SDS-PAGE, size exclusion chromatography, Western blotting, and LC-MSE peptide mapping. Binding characteristics were determined by ELISA and flow cytometry assays. To improve the stability of the conjugates at physiologic pH, the pIs of the V21 antibodies were adjusted by adding several amino acid residues to the C-terminus. For V21H4, a terminal cysteine was also added for use in the conjugation chemistry. The modified V21 antibodies were expressed in the E. coli BL21 (DE3 pT7 system. V21H1 was conjugated to urease using the heterobifunctional cross-linker succinimidyl-[(N-maleimidopropionamido-diethyleneglycol] ester (SM(PEG2, which targets lysine resides in the antibody. V21H4 was conjugated to urease using the homobifunctional cross-linker, 1,8-bis

Ophiamides A-B, new potent urease inhibitory sphingolipids from Heliotropium ophioglossum.

Science.gov (United States)

Firdous, Sadiqa; Ansari, Nida Hassan; Fatima, Itrat; Malik, Abdul; Afza, Nighat; Iqbal, Lubna; Lateef, Mehreen

2012-07-01

Ophiamides A (1) and B (2), two new sphingolipids have been isolated from the n-hexane subfraction of the MeOH extract of the whole plant of Heliotropium ophioglossum along with glycerol monopalmitate (3) and β-sitosterol 3-O-β-D: -glucoside (4) reported for the first time from this species. Their structures were elucidated by spectroscopic techniques including MS and 2D-NMR spectroscopy. Both the compounds 1 and 2 showed potent inhibitory activity against the enzyme urease.

An in vitro study of enhanced H+ diffusion by urease action on urea. Implications for Helicobacter pylori-associated peptic ulceration.

Science.gov (United States)

Desai, M A; Vadgama, P M

1993-10-01

The in vitro effect of urea and hydrolysis of urea by urease on mucus H+ permeability is reported here. The effective DHCl values indicate a strong pH dependence for H+ diffusion in both water and mucus layers, with no apparent trend at concentrations between 1 and 50 mM urea. However, the estimated DHCl at near-neutral and alkaline pH are 4- to 10-fold lower through mucus than through aqueous films. Moreover, the pKa values of HCO3- and NH3 (generated by urease action on urea) had a profound effect on measured DHCl. These in vitro studies suggest that a high local concentration of NH3 and HCO3- within the mucus layer, generated by the action of Helicobacter pylori urease on endogenous intragastric urea, could greatly accelerate proton flux to the surface epithelium by operation of a buffer shuttle. This results in enhanced H+ permeability, particularly at pKa values of HCO3- and NH3, and in extreme circumstances it may result in gastric ulcer formation.

Iron-responsive repression of urease expression in Helicobacter hepaticus is mediated by the transcriptional regulator Fur

NARCIS (Netherlands)

C. Belzer (Clara); B.A.M. van Schendel (Bart A.); E.J. Kuipers (Ernst); J.G. Kusters (Johannes); A.H.M. van Vliet (Arnoud)

2007-01-01

textabstractPersistent colonization of mucosal surfaces by bacteria in the mammalian host requires concerted expression of colonization factors, depending on the environmental conditions. Helicobacter hepaticus is a urease-positive pathogen that colonizes the intestinal and hepatobiliary tracts of

Sucralfate significantly reduces ciprofloxacin concentrations in serum.

OpenAIRE

Garrelts, J C; Godley, P J; Peterie, J D; Gerlach, E H; Yakshe, C C

1990-01-01

The effect of sucralfate on the bioavailability of ciprofloxacin was evaluated in eight healthy subjects utilizing a randomized, crossover design. The area under the concentration-time curve from 0 to 12 h was reduced from 8.8 to 1.1 micrograms.h/ml by sucralfate (P less than 0.005). Similarly, the maximum concentration of ciprofloxacin in serum was reduced from 2.0 to 0.2 micrograms/ml (P less than 0.005). We conclude that concurrent ingestion of sucralfate significantly reduces the concentr...

Enhanced Peroxide Resistance of In Vitro Mutagenized Fluorideresistant Klebsiella pneumoniae Ureases for Catalytic Buffering of Agent Decontamination Reactions

National Research Council Canada - National Science Library

Fry, Ilona J; DeFrank, Joseph J

2004-01-01

...) and oxidative surety agent decontamination technologies. Ammonia production from urea by urease neutralizes the production of Oalkylphosphonic acids resulting from the hydrolysis of Nerve agents such as Sarin and VX...

Ferrocene-based guanidine derivatives: in vitro antimicrobial, DNA binding and docking supported urease inhibition studies.

Science.gov (United States)

Gul, Rukhsana; Rauf, Muhammad Khawar; Badshah, Amin; Azam, Syed Sikander; Tahir, Muhammad Nawaz; Khan, Azim

2014-10-06

Some novel ferrocenyl guanidines 1-8 were synthesized and characterized by different spectroscopic methods, elemental analysis and single crystal X-rays diffraction techniques. The crystallographic studies revealed that the existence of the strong non-bonding interactions facilitate these molecules to interact with biological macro-molecules like DNA that described to inherit good biological activities. The DNA interaction studies carried out by cyclic voltammetry (CV) and UV-visible spectroscopy are in close agreement with the binding constants (K) (0.79-5.4) × 10(5) (CV) and (0.72-5.1) × 10(5) (UV-vis). The shift in peak potential, current and absorption maxima of the studied ferrocenyl guanidines in the presence of DNA revealed that CV coupled with UV-vis spectroscopy could provide an opportune to characterize metal-based compounds-DNA interaction mechanism, a prerequisite for the design of new anticancer agents and understanding the molecular basis of their action. The compounds 1-8 have been screened for their antibacterial, antifungal and urease inhibition potency. A concurrent in silico study has also been applied on ferrocene moiety impregnated guanidines 1-8 to identify most active compounds having for inhibiting the activity of urease (pdb id 3LA4). Most of the compounds were found as potent inhibitors of urease and the compound 1 was found to be the most active with an IC50 of 16.83 ± 0.03 μM. The docking scores are in close agreement with the in vitro obtained IC50 values of inhibitors 1-8. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Vibrio parahaemolyticus produtores de urease isolados a partir de ostras (Crassostrea rizophorae coletadas in natura em restaurantes e mexilhões (Perna perna de banco natural Vibrio parahaemolyticus urease positive isolated from in natura oysters (Crassostrea rizophorae collected at restaurants and mussels (Perna perna harvested from natural habitat

Directory of Open Access Journals (Sweden)

Chistiane Soares Pereira

2004-12-01

Full Text Available A presença de Vibrio parahaemolyticus foi avaliada em 50 amostras de moluscos bivalves marinhos compostas por 40 amostras de ostras coletadas em 15 restaurantes do Rio de Janeiro e 10 amostras de mexilhões capturados de banco natural em Ponta de Itaipú - Niterói. Foram empregadas a técnica do Número Mais Provável (NMP para a enumeração de V. parahaemolyticus utilizando Caldo Glicosado Salgado com Teepol (GSTB e Água Peptonada Alcalina (APA com 3% de cloreto de sódio (NaCl. Paralelamente foi realizada técnica de enriquecimento em APA com 1 e 3% de NaCl. Decorrido o período de incubação de ambas as técnicas, foi realizado plaqueamento em ágar TCBS (Tiossulfato Citrato Bile Sacarose. Todas as cepas de V. parahaemolyticus isoladas através das duas técnicas foram testadas para o fenômeno de Kanagawa e, quanto à produção de urease. Do total de 141 cepas de V. parahaemolyticus isoladas, 62% revelaram-se urease positivas e, dentre estas, os sorotipos predominantes foram O10:K?, O11:K? e O3:K57 dentre o total de 24 sorotipos urease positivos identificados. Embora todas as cepas de V. parahaemolyticus tenham sido Kanagawa negativas, os resultados apontam elevada incidência desta espécie em ostras comercializadas em restaurantes.The presence of Vibrio parahaemolyticus were detected in 50 marine bivalve mollusks composed by 40 oysters samples collected at 15 restaurants in Rio de Janeiro City and 10 wild mussels' samples harvested in Ponta de Itaipu-Niterói. The Most Probable Number (MPN technique was employed for the enumeration of V. parahaemolyticus, using glucose salt teepol broth (GSTB and alcaline peptone water (APW with 3% NaCl. At the same time, the samples were submitted on direct plating with APW added 1 and 3% NaCl. Both techniques were followed by plating onto TCBS agar. All the V. parahaemolyticus strains isolated were tested for Kanagawa phenomenon and they were also tested for the presence of urease. A total of 141 V

A Determination and Comparison of Urease Activity in Feces and Fresh Manure from Pig and Cattle in Relation to Ammonia Production and pH Changes

Science.gov (United States)

Dai, Xiaorong; Karring, Henrik

2014-01-01

Ammonia emission from animal production is a major environmental problem and has impacts on the animal health and working environment inside production houses. Ammonia is formed in manure by the enzymatic degradation of urinary urea and catalyzed by urease that is present in feces. We have determined and compared the urease activity in feces and manure (a urine and feces mixture) from pigs and cattle at 25°C by using Michaelis-Menten kinetics. To obtain accurate estimates of kinetic parameters Vmax and K'm, we used a 5 min reaction time to determine the initial reaction velocities based on total ammoniacal nitrogen (TAN) concentrations. The resulting Vmax value (mmol urea hydrolyzed per kg wet feces per min) was 2.06±0.08 mmol urea/kg/min and 0.80±0.04 mmol urea/kg/min for pig feces and cattle feces, respectively. The K'm values were 32.59±5.65 mmol urea/l and 15.43±2.94 mmol urea/l for pig feces and cattle feces, respectively. Thus, our results reveal that both the Vmax and K'm values of the urease activity for pig feces are more than 2-fold higher than those for cattle feces. The difference in urea hydrolysis rates between animal species is even more significant in fresh manure. The initial velocities of TAN formation are 1.53 mM/min and 0.33 mM/min for pig and cattle manure, respectively. Furthermore, our investigation shows that the maximum urease activity for pig feces occurs at approximately pH 7, and in cattle feces it is closer to pH 8, indicating that the predominant fecal ureolytic bacteria species differ between animal species. We believe that our study contributes to a better understanding of the urea hydrolysis process in manure and provides a basis for more accurate and animal-specific prediction models for urea hydrolysis rates and ammonia concentration in manures and thus can be used to predict ammonia volatilization rates from animal production. PMID:25397404

Biosensors Based on Urease Adsorbed on Nickel, Platinum, and Gold Conductometric Transducers Modified with Silicalite and Nanozeolites

Science.gov (United States)

Kucherenko, Ivan S.; Soldatkin, Oleksandr O.; Kasap, Berna Ozansoy; Kurç, Burcu Akata; Melnyk, Volodymir G.; Semenycheva, Lyudmila M.; Dzyadevych, Sergei V.; Soldatkin, Alexei P.

This work describes urease-based conductometric biosensors that were created using nontypical method of urease immobilization via adsorption on micro- and nanoporous particles: silicalite and nanocrystalline zeolites Beta (BEA) and L. Conductometric transducers with nickel, gold, and platinum interdigitated electrodes were used. Active regions of the nickel transducers were modified with microparticles using two procedures—spin coating and drop coating. Gold and platinum transducers were modified with silicalite using drop coating since it was more effective. Scanning electron microscopy was used to evaluate effectiveness of these procedures. The procedure of spin coating produced more uniform layers of particles (and biosensors had good reproducibility of preparation), but it was more complicated, drop coating was easier and led to formation of a bulk of particles; thus, biosensors had bigger sensitivity but worse reproducibility of preparation. Urease was immobilized onto transducers modified with particles by physical adsorption. Analytical characteristics of the obtained biosensors for determination of urea (calibration curves, sensitivity, limit of detection, linear concentration range, noise of responses, reproducibility of signal during a day, and operational stability during 3 days) were compared. Biosensors with all three particles deposited by spin coating showed similar characteristics; however, silicalite was a bit more effective. Biosensors based on nickel transducers modified by drop coating had better characteristics in comparison with modification by spin coating (except reproducibility of preparation). Transducers with gold electrodes showed best characteristics while creating biosensors, platinum electrodes were slightly inferior to them, and nickel electrodes were the worst.

Nickel Ligation of the N-Terminal Amine of HypA Is Required for Urease Maturation in Helicobacter pylori.

Science.gov (United States)

Hu, Heidi Q; Johnson, Ryan C; Merrell, D Scott; Maroney, Michael J

2017-02-28

The human pathogen Helicobacter pylori requires nickel for colonization of the acidic environment of the stomach. HypA, a Ni metallochaperone that is typically associated with hydrogenase maturation, is also required for urease maturation and acid survival of H. pylori. There are two proposed Ni site structures for HypA; one is a paramagnetic six-coordinate site characterized by X-ray absorption spectroscopy (XAS) in unmodified HypA, while another is a diamagnetic four-coordinate planar site characterized by solution nuclear magnetic resonance in an N-terminally modified HypA construct. To determine the role of the N-terminal amine in Ni binding of HypA, an N-terminal extension variant, L2*-HypA, in which a leucine residue was inserted into the second position of the amino acid sequence in the proposed Ni-binding motif, was characterized in vitro and in vivo. Structural characterization of the Ni site using XAS showed a coordination change from six-coordinate in wild-type HypA (WT-HypA) to five-coordinate pyramidal in L2*-HypA, which was accompanied by the loss of two N/O donor protein ligands and the addition of an exogenous bromide ligand from the buffer. The magnetic properties of the Ni sites in WT-HypA compared to those of the Ni sites in L2*-HypA confirmed that a spin-state change from high to low spin accompanied this change in structure. The L2*-HypA H. pylori strain was shown to be acid sensitive and deficient in urease activity in vivo. In vitro characterization showed that L2*-HypA did not disrupt the HypA-UreE interaction that is essential for urease maturation but was at least 20-fold weaker in Ni binding than WT-HypA. Characterization of the L2*-HypA variant clearly demonstrates that the N-terminal amine of HypA is involved in proper Ni coordination and is necessary for urease activity and acid survival.

A cheap, simple high throughput method for screening native Helicobacter pylori urease inhibitors using a recombinant Escherichia coli, its validation and demonstration of Pistacia atlantica methanolic extract effectivity and specificity.

Science.gov (United States)

Amar, Natalie; Peretz, Avi; Gerchman, Yoram

2017-02-01

Helicobacter pylori is the most frequent and persistent bacterial infection worldwide, and a risk factor for active gastritis, peptic ulcers, mucosa-associated lymphoid tissue lymphoma, and gastric cancer. Although combined antibiotics treatment is effective cases of antibiotic resistance are reported at an alarming rate. The H. pylori urease enzyme is essential for the bacteria establishment in the gastric mucosa, resulting urease inhibitors being sought after as effective and specific anti- H. pylori treatment. To-date, screening assays are based mostly on the analog plant urease enzyme but difference in properties of the plant and bacterial enzymes hamper these efforts. We have developed a screening assay based on recombinant Escherichia coli expressing native H. pylori urease, and validated this assay using thiourea and a methanolic extract of Pistacia atlantica. The assay demonstrated the thiourea and the extract to be potent urease inhibitors, with the extract having strong bacteriostatic activity against clinical isolates of H. pylori, including such with antibiotic resistance. The extract was also found to be neutral toward common probiotic bacteria, supporting its specificity and compatibility with digestive system desired microflora and suggesting it could be a good source for anti-H. pylori compounds. The assay has proven to be cheap, simple and native alternative to the plant enzyme based assay and could allow for high throughput screening for new urease inhibitors and could expedite screening and development of novel, better H. pylori remedies helping us to combat this infection. Copyright © 2016 Elsevier B.V. All rights reserved.

A Urea Biosensor from Stacked Sol-Gel Films with Immobilized Nile Blue Chromoionophore and Urease Enzyme

Directory of Open Access Journals (Sweden)

Musa Ahmad

2007-10-01

Full Text Available An optical urea biosensor was fabricated by stacking several layers of sol-gelfilms. The stacking of the sol-gel films allowed the immobilization of a Nile Bluechromoionophore (ETH 5294 and urease enzyme separately without the need of anychemical attachment procedure. The absorbance response of the biosensor was monitoredat 550 nm, i.e. the deprotonation of the chromoionophore. This multi-layer sol-gel filmformat enabled higher enzyme loading in the biosensor to be achieved. The urea opticalbiosensor constructed from three layers of sol-gel films that contained urease demonstrateda much wider linear response range of up to 100 mM urea when compared with biosensorsthat constructed from 1-2 layers of films. Analysis of urea in urine samples with thisoptical urea biosensor yielded results similar to that determined by a spectrophotometricmethod using the reagent p-dimethylaminobenzaldehyde (R2 = 0.982, n = 6. The averagerecovery of urea from urine samples using this urea biosensor is approximately 103%.

A Urea Biosensor from Stacked Sol-Gel Films with Immobilized Nile Blue Chromoionophore and Urease Enzyme.

Science.gov (United States)

Alqasaimeh, Muawia Salameh; Heng, Lee Yook; Ahmad, Musa

2007-10-11

An optical urea biosensor was fabricated by stacking several layers of sol-gelfilms. The stacking of the sol-gel films allowed the immobilization of a Nile Bluechromoionophore (ETH 5294) and urease enzyme separately without the need of anychemical attachment procedure. The absorbance response of the biosensor was monitoredat 550 nm, i.e. the deprotonation of the chromoionophore. This multi-layer sol-gel filmformat enabled higher enzyme loading in the biosensor to be achieved. The urea opticalbiosensor constructed from three layers of sol-gel films that contained urease demonstrateda much wider linear response range of up to 100 mM urea when compared with biosensorsthat constructed from 1-2 layers of films. Analysis of urea in urine samples with thisoptical urea biosensor yielded results similar to that determined by a spectrophotometricmethod using the reagent p-dimethylaminobenzaldehyde (R² = 0.982, n = 6). The averagerecovery of urea from urine samples using this urea biosensor is approximately 103%.

Editing of the urease gene by CRISPR-Cas in the diatom Thalassiosira pseudonana

Directory of Open Access Journals (Sweden)

Amanda Hopes

2016-11-01

Full Text Available Abstract Background CRISPR-Cas is a recent and powerful addition to the molecular toolbox which allows programmable genome editing. It has been used to modify genes in a wide variety of organisms, but only two alga to date. Here we present a methodology to edit the genome of Thalassiosira pseudonana, a model centric diatom with both ecological significance and high biotechnological potential, using CRISPR-Cas. Results A single construct was assembled using Golden Gate cloning. Two sgRNAs were used to introduce a precise 37 nt deletion early in the coding region of the urease gene. A high percentage of bi-allelic mutations (≤61.5% were observed in clones with the CRISPR-Cas construct. Growth of bi-allelic mutants in urea led to a significant reduction in growth rate and cell size compared to growth in nitrate. Conclusions CRISPR-Cas can precisely and efficiently edit the genome of T. pseudonana. The use of Golden Gate cloning to assemble CRISPR-Cas constructs gives additional flexibility to the CRISPR-Cas method and facilitates modifications to target alternative genes or species.

Urease inhibitor (NBPT and efficiency of single or split application of urea in wheat crop

Directory of Open Access Journals (Sweden)

Marcelo Curitiba Espindula

2014-04-01

Full Text Available NBPT (N-(n-butyl thiophosphoric triamide, a urease inhibitor, has been reported as one of the most promising compounds to maximize urea nitrogen use in agricultural systems. The objective of this study was to evaluate the performance of irrigated wheat fertilized with urea or urea + NBPT as single or split application. The experiment was conducted from June to October 2006 in Viçosa, MG, Brazil. The experimental design followed a 2×2 factorial scheme, in which urea or urea + NBPT were combined with two modes of application: full dose at sowing (60kg ha-1 or split (20kg ha-1 at sowing + 40kg ha-1 as topdressing at tillering, in randomized blocks with ten replications. The split application of nitrogen fertilization does not improve the yield wheat under used conditions. The use of urease inhibitor improves the grain yield of wheat crop when urea is applied in topdressing at tillering, but its use does not promote difference when urea is applied in the furrow at planting.

Anti-urease Secondary Metabolites from Seriphidium quettense

Directory of Open Access Journals (Sweden)

Muhammad Imran Tousif

2017-03-01

Full Text Available Ethyl acetate layer of the methanolic extract of Seriphidium quettense was subjected to silica gel column chromatography to isolate one new; seriphiloid (1, and four known compounds; ilicic acid (2, 6 a -hydroxy-8(10-oplopen-14-one (3, 2-(4-hydroxyphenyl-5,6,7-trimethoxy-4H-chromen-4-one (4 and 2-(3,4-dihydroxyphenyl-5,6,7-trimethoxy-4H-chromen-4-one (5. The chemical structure of the new isolate was established with the help of 1D, 2D NMR techniques and high resolution mass spectrometry. Known compounds were identified because of 1D NMR and mass spectrometric analysis and in comparison with the literature values. Compounds 1-5 were evaluated for their acetylcholinesterase, butyrylcholinesterase, a -glucosidase and urease inhibitory activities. Most of the metabolites were found inactive; however, compounds 2 and 3 showed good antiurease activity with IC 50 value 21.5±0.1 and 20.8±0.1 µg/mL, respectively.

Algal polysaccharides as matrices for the immobilization of urease in lipid ultrathin films studied with tensiometry and vibrational spectroscopy: Physical-chemical properties and implications in the enzyme activity.

Science.gov (United States)

de Brito, Audrey Kalinouski; Nordi, Cristina S F; Caseli, Luciano

2015-11-01

Currently, many biological substances extracted from algae have received special attention because of their intrinsic characteristics, which can be applied to different areas of biotechnology. Therefore, in the current study, exopolysaccharides (EPS) from the microalgae Cryptomonas tetrapirenoidosa were employed as an aqueous subphase of a monolayer formed by the lipid dioctadecyldimethylammonium bromide (DODAB). The primary objective of this approach was to evaluate whether EPS could serve as a matrix for the immobilization of the enzyme urease to produce biosensors for urea. After DODAB was spread on the EPS solutions, urease was injected into the aqueous subphase, and the surface was submitted to compression using lateral barriers. The monolayers were subsequently characterized by surface pressure-area isotherms and polarization modulation infrared reflection-absorption spectroscopy (PM-IRRAS). The results indicated that EPS enhanced the adsorption of the enzyme on the lipid monolayer. The mixed films were later transferred to solid supports using the Langmuir-Blodgett (LB) technique and were characterized by transfer ratio, PM-IRRAS, quartz crystal microbalance, and atomic force microscopy. The immobilization of the enzyme on solid supports was fundamental for providing an ideal geometrical accommodation of urease because the interaction of EPS with urease in solution causes a decrease of the relative activity of urease. Therefore, these LB films are promising for the fabrication of future urea biosensors, the architecture of which can be manipulated and enhanced at the molecular level. Copyright © 2015 Elsevier B.V. All rights reserved.

How Helicobacter pylori urease may affect external pH and influence growth and motility in the mucus environment: evidence from in-vitro studies.

Science.gov (United States)

Sidebotham, Ramon L; Worku, Mulugeta L; Karim, Q Najma; Dhir, Nirmal K; Baron, J Hugh

2003-04-01

Survival of Helicobacter pylori is dependent upon urease in the cytoplasm and at the bacterial surface. We have sought to clarify how alkaline ammonium salts, released from urea by this enzyme, might alter mucus pH and so affect growth and motility of the bacterium in the gastric mucus environment. Experiments were conducted in vitro to determine how the growth and motility of H. pylori are affected by changes in external pH, and how the bacterium, by hydrolysing urea, alters the pH of the bicarbonate buffer that occurs at the gastric mucosal surface. These data were fitted into experimental models that describe how pH varies within the mucus layer in the acid-secreting stomach. H. pylori was motile between pH 5 and 8, with optimal motility at pH 5. It grew between pH 6 and 8, with optimal growth at pH 6. The bacterium had urease activity between pH 2.7 and 7.4, as evidenced by pH rises in bicarbonate-buffered solutions of urea. Changes in buffer pH were dependent upon initial pH and urea concentration, with the greatest rate of pH change occurring at pH 3. Modelling experiments utilizing these data indicated that (1) in the absence of urease, H. pylori growth and motility in the mucus layer would be restricted severely by low mucus pH in the acid-secreting stomach, and (2) urease will sometimes inhibit H. pylori growth and motility in the mucus layer by elevating the pH of the mucus environment above pH 8. Urease is essential to the growth and motility of H. pylori in the mucus layer in the acid-secreting stomach, but, paradoxically, sometimes it might suppress colonization by raising the mucus pH above 8. This latter effect may protect the bacteria from the adverse consequences of overpopulation.

Enzymatic, urease-mediated mineralization of gellan gum hydrogel with calcium carbonate, magnesium-enriched calcium carbonate and magnesium carbonate for bone regeneration applications

DEFF Research Database (Denmark)

Douglas, Timothy; Lapa, Agata; Samal, Sangram K.

carbonate to generate composite biomaterials for bone regeneration. GG is an inexpensive, biotechnologically produced anionic polysaccharide, from which hydrogels for cartilage regeneration have been formed by crosslinking with divalent ions[3]. Methods: GG hydrogels were loaded with the enzyme urease...... by incubation in 5% (w/v) urease solution and mineralized for 5 days in five different media denoted as UA, UB, UC, UD and UE, which contained urea (0.17 M) and different concentrations of CaCl2 and MgCl2 (270:0, 202.5:67.5, 135:135, 67.5:202.5 and 0:250, respectively (mmol dm-3)). Discs were autoclaved...

Influence of Enzyme Quantity and Distribution on the Self-Propulsion of Non-Janus Urease-Powered Micromotors.

Science.gov (United States)

Patiño, Tania; Feiner-Gracia, Natalia; Arqué, Xavier; Miguel-López, Albert; Jannasch, Anita; Stumpp, Tom; Schäffer, Erik; Albertazzi, Lorenzo; Sánchez, Samuel

2018-05-29

The use of enzyme catalysis to power micro- and nanomachines offers unique features such as biocompatibility, versatility, and fuel bioavailability. Yet, the key parameters underlying the motion behavior of enzyme-powered motors are not completely understood. Here, we investigate the role of enzyme distribution and quantity on the generation of active motion. Two different micromotor architectures based on either polystyrene (PS) or polystyrene coated with a rough silicon dioxide shell (PS@SiO 2 ) were explored. A directional propulsion with higher speed was observed for PS@SiO 2 motors when compared to their PS counterparts. We made use of stochastically optical reconstruction microscopy (STORM) to precisely detect single urease molecules conjugated to the micromotors surface with a high spatial resolution. An asymmetric distribution of enzymes around the micromotor surface was observed for both PS and PS@SiO 2 architectures, indicating that the enzyme distribution was not the only parameter affecting the motion behavior. We quantified the number of enzymes present on the micromotor surface and observed a 10-fold increase in the number of urease molecules for PS@SiO 2 motors compared to PS-based micromotors. To further investigate the number of enzymes required to generate a self-propulsion, PS@SiO 2 particles were functionalized with varying amounts of urease molecules and the resulting speed and propulsive force were measured by optical tracking and optical tweezers, respectively. Surprisingly, both speed and force depended in a nonlinear fashion on the enzyme coverage. To break symmetry for active propulsion, we found that a certain threshold number of enzymes molecules per micromotor was necessary, indicating that activity may be due to a critical phenomenon. Taken together, these results provide new insights into the design features of micro/nanomotors to ensure an efficient development.

Efeito da temperatura, pH e vestígios de Hg2+ e Pb2+ na acti­vidade de desidrogenases e urease num solo da região de Évora Effect of temperature, pH and Hg2+ and Pb2+ traces in dehydrogenaseand urease activities of a soil from Évora region

Directory of Open Access Journals (Sweden)

M. R. Martins

2010-01-01

Full Text Available As actividades das enzimas no solo são um importante indicador da sua qualida­de. Neste estudo procedeu-se à caracteri­zação da actividade enzimática de desi­drogenases (EC 1.1.1 e da urease (EC 3.5.1.5 de um solo sob Olea europeae L. da região de Évora. As constantes cinéti­cas Km e Vmáx, foram determinadas usando como substratos o cloreto de p­-iodonitrotetrazolio (INT e a ureia, res­pectivamente. Foi avaliado o efeito nas referidas actividades provocado pelo pH, temperatura e vestígios de Hg2+ e de Pb2+. As actividades máximas obtiveram-se a pH = 8,5 e 40 ºC, com Km= 0,5 mM e Vmáx = 5,4 µmol min-1 g-1, para a activida­de de desidrogenases e a pH = 10 e 37 ºC, com Km = 25,7 mM e Vmáx = 2,0x10-2 µmol min-1 g-1, para a urease. Estas acti­vidades foram inibidas por diferentes concentrações de Hg2+, mas apenas a acti­vidade da urease foi inibida pelo Pb2+. Estes resultados são comparáveis com os referidos na literatura para estes enzimas.Enzyme activities are often used as in­dicator of soil quality. This study reports on dehydrogenase (EC 1.1.1 and urease (EC 3.5.1.5 activities of a soil under Olea europaea L. from Évora region. Kinetic constants Km and Vmax were determined using p-iodonitrotetrazolium chloride (INT and urea, respectively. Effects of pH, temperature and Hg2+ and Pb2+ traces on both activities were determined. Maximal activity was obtained at pH = 8.5 and 40ºC, Km = 0.5 mM and Vmax=5,4µmol min-1 g-1 , for dehydro­genase and at pH = 10 and 37 ºC, Km = 25.7 mM and Vmax = 2.0x10-2 µmol min-1 g-1, for urease. These activities were in­hibited by different concentrations of Hg2+, but only the urease activity was in­hibited by Pb2+. Results of this study are comparable to those reported in the litera­ture for these enzymes.

Cytoplasmic Histidine Kinase (HP0244)-Regulated Assembly of Urease with UreI, a Channel for Urea and Its Metabolites, CO2, NH3, and NH4+, Is Necessary for Acid Survival of Helicobacter pylori▿

OpenAIRE

Scott, David R.; Marcus, Elizabeth A.; Wen, Yi; Singh, Siddarth; Feng, Jing; Sachs, George

2009-01-01

Helicobacter pylori colonizes the normal human stomach by maintaining both periplasmic and cytoplasmic pH close to neutral in the presence of gastric acidity. Urease activity, urea flux through the pH-gated urea channel, UreI, and periplasmic α-carbonic anhydrase are essential for colonization. Exposure to pH 4.5 for up to 180 min activates total bacterial urease threefold. Within 30 min at pH 4.5, the urease structural subunits, UreA and UreB, and the Ni2+ insertion protein, UreE, are recrui...

Emended description of Campylobacter sputorum and revision of its infrasubspecific (biovar) divisions, including C-sputorum biovar paraureolyticus, a urease-producing variant from cattle and humans

DEFF Research Database (Denmark)

On, S.L.W.; Atabay, H.I.; Corry, J.E.L.

1998-01-01

A polyphasic taxonomic study of 15 bovine and human strains assigned to the catalase-negative, urease-positive campylobacter (CNUPC) group identified these bacteria as a novel, ureolytic biovar of Campylobacter sputorum for which we propose the name C. sputorum bv. paraureolyticus: suitable...... should be revised to include by. sputorum for catalase-negative strains; by. fecalis for catalase-positive strains; and by. paraureolyticus for urease-positive strains. Strains classified previously as by. bubulus should be reclassified as by. sputorum. The species description of C. sputorum is revised...

Phytochemical Constituents, ChEs and Urease Inhibitions, Antiproliferative and Antioxidant Properties of Elaeagnus umbellata Thunb.

Science.gov (United States)

Ozen, Tevfik; Yenigun, Semiha; Altun, Muhammed; Demirtas, Ibrahim

2017-01-01

Due to the common ethnopharmacological used or scientifically examined biochemical properties, Elaeagnaceae family, Elaeagnus umbellate (Thunb.) (EU, Guz yemisi) was worth investigating. In this investigation, we revealed antioxidant, antiproliferative and enzyme inhibition activities of the water, methanol, ethanol, acetone, ethyl acetate and hexane extracts of EU as well as the contents of their phenolic, flavonoid, anthocyanin, ascorbic acid, lycopene and β- carotene. The antioxidant activity was screened by total antioxidant (phosphomolybdenum), inhibition of linoleic acid peroxidation, reducing power, 2-deoxyribose degradation assay, H2O2 scavenging and metal chelating activities of the samples were tested in vitro. Additionally, the scavenging activities of the extracts were determined against 1,1-diphenyl-2-picrylhydrazyl (DPPH˙), 2,2-azino-bis(3-ethylbenzothiazloine-6-sulfonicacid (ABTS˙+), superoxide anion and peroxide radicals. The samples were determined for their inhibitory activities against urease, acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). In vitro, antiproliferative activities of six different extracts were tested using the xCELLigence system against HeLa and HT29 cell lines. The antioxidant activities of the extracts were found higher than standard antioxidants. The water extracts of fruit and leaf showed the best antioxidant activity. In inhibition assays of urease, AChE and BuChE, all extracts exhibited remarkable inhibition potential. Ethyl acetate extracts, especially, showed better inhibition capacity. It was found that the antioxidant activities of the extracts presented consistently with their chemical contents. The antiproliferative activities of leaf extracts were more effective than the fruit extracts. The chromatographic methods were applied to the different solvents to analyses phenolic secondery metabolites. It was found that fumaric acid, 4- hydroxybenzoic acid, rutin and quercetin-3-�

Sistema em fluxo para determinação espectrofotométrica de uréia em plasma de sangue animal empregando leguminosa como fonte natural da enzima urease

Directory of Open Access Journals (Sweden)

Luca Gilmara C.

2001-01-01

Full Text Available A spectrophotometric flow injection analysis (FIA procedure employing natural urease enzyme source for the determination of urea in animal blood plasma was developed. Among leguminous plants used in the Brazilian agriculture, the Cajanus cajan specie was selected as urease source considering its efficiency and availability. A minicolumn was filled with leguminous fragments and coupled to the FIA manifold, where urea was on-line converted to ammonium ions and subsequently it was quantified by spectrophotometry. The system was employed to determine urea in animal plasma samples without any prior treatment. Accuracy was assessed by comparison results with those obtained employing the official procedure and no significant difference at 90 % confidence level was observed. Other profitable features such as an analytical throughput of 30 determinations per hour, a reagent consumption of 19.2 mg sodium salicylate, 0.5 mg sodium hipochloride and a relative standard deviation of 1.4 % (n= 12 were also obtained.

Nickel Ligation of the N-Terminal Amine of HypA Is Required for Urease Maturation in Helicobacter pylori

Energy Technology Data Exchange (ETDEWEB)

Hu, Heidi Q. [Department; Johnson, Ryan C. [Microbiology; Merrell, D. Scott [Microbiology; Maroney, Michael J. [Department

2017-02-17

The human pathogen Helicobacter pylori requires nickel for colonization of the acidic environment of the stomach. HypA, a Ni metallochaperone that is typically associated with hydrogenase maturation, is also required for urease maturation and acid survival of H. pylori. There are two proposed Ni site structures for HypA; one is a paramagnetic six-coordinate site characterized by X-ray absorption spectroscopy (XAS) in unmodified HypA, while another is a diamagnetic four-coordinate planar site characterized by solution nuclear magnetic resonance in an N-terminally modified HypA construct. To determine the role of the N-terminal amine in Ni binding of HypA, an N-terminal extension variant, L2*-HypA, in which a leucine residue was inserted into the second position of the amino acid sequence in the proposed Ni-binding motif, was characterized in vitro and in vivo. Structural characterization of the Ni site using XAS showed a coordination change from six-coordinate in wild-type HypA (WT-HypA) to five-coordinate pyramidal in L2*-HypA, which was accompanied by the loss of two N/O donor protein ligands and the addition of an exogenous bromide ligand from the buffer. The magnetic properties of the Ni sites in WT-HypA compared to those of the Ni sites in L2*-HypA confirmed that a spin-state change from high to low spin accompanied this change in structure. The L2*-HypA H. pylori strain was shown to be acid sensitive and deficient in urease activity in vivo. In vitro characterization showed that L2*-HypA did not disrupt the HypA–UreE interaction that is essential for urease maturation but was at least 20-fold weaker in Ni binding than WT-HypA. Characterization of the L2*-HypA variant clearly demonstrates that the N-terminal amine of HypA is involved in proper Ni coordination and is necessary for urease activity and acid survival.

Urease-positive thermophilic strains of Campylobacter isolated from seagulls (Larus spp.).

Science.gov (United States)

Kaneko, A; Matsuda, M; Miyajima, M; Moore, J E; Murphy, P G

1999-07-01

Three strains of urease-positive thermophilic Campylobacter (UPTC), designated A1, A2 and A3, were identified by biochemical characterization after isolation from faeces of seagulls in Northern Ireland in 1996. The biochemical characteristics of the strains were identical to those of strains described previously. Analysis by pulsed-field gel electrophoresis (PFGE) after separate digestion with ApaI and SmaI demonstrated that the respective PFGE profiles were indistinguishable. The PFGE analysis also suggested that the genomes were approximately 1810 kb in length. This is the first example of the isolation of UPTC from flying homoiothermal animals, i.e. from seagulls (Larus spp.).

Transformation and characterization of an arsenic gene operon from urease-positive thermophilic Campylobacter (UPTC) in Escherichia coli.

Science.gov (United States)

Matsuda, M; Kuribayashi, T; Yamamoto, S; Millar, B C; Moore, J E

2016-01-01

An arsenate susceptibility test was performed with transformed and cultured Escherichia coli DH5α cells, which carried recombinant DNA of full-length arsenic (ars) operon, namely a putative membrane permease, ArsP; a transcriptional repressor, ArsR; an arsenate reductase, ArsC; and an arsenical-resistance membrane transporter, Acr3, from the Japanese urease-positive thermophilic Campylobacter lari (UPTC) CF89-12. The E. coli DH5α transformant showed reduced susceptibility to arsenate (~1536 μg/mL), compared to the control. Thus, these ars four-genes from the UPTC CF89-12 strain cells could confer a reduced susceptibility to arsenate in the transformed and E. coli DH5α cells. E. coli transformants with truncated ars operons, acr3 (acr3) and arsC-acr3 (∆arsC-acr3), of the ars operon, showed an MIC value of 384 μg/mL (~384 μg/mL), similar to the E. coli cells which carried the pGEM-T vector (control). Reverse transcription PCR confirmed in vivo transcription of recombinant full-length ars operon and deletion variants (∆acr3 and ∆arsC-acr3) in the transformed E. coli cells.

Role of the Helicobacter pylori virulence factors vacuolating cytotoxin, CagA, and urease in a mouse model of disease.

Science.gov (United States)

Ghiara, P; Marchetti, M; Blaser, M J; Tummuru, M K; Cover, T L; Segal, E D; Tompkins, L S; Rappuoli, R

1995-10-01

The pathogenic role of Helicobacter pylori virulence factors has been studied with a mouse model of gastric disease. BALB/c mice were treated orally with different amounts of sonic extracts of cytotoxic H. pylori strains (NCTC 11637, 60190, 84-183, and 87A300 [CagA+/Tox+]). The pathological effects on histological sections of gastric mucosae were assessed and were compared with the effects of treatments with extracts from noncytotoxic strains (G21 and G50 [CagA-/Tox-]) and from strains that express either CagA alone (D931 [CagA+/Tox-]) or the cytotoxin alone (G104 [CagA-/Tox+]). The treatment with extracts from cytotoxic strains induced various epithelial lesions (vacuolation, erosions, and ulcerations), recruitment of inflammatory cells in the lamina propria, and a marked reduction of the mucin layer. Extracts of noncytotoxic strains induced mucin depletion but no other significant pathology. Crude extracts of strain D931, expressing CagA alone, caused only mild infiltration of inflammatory cells, whereas extracts of strain G104, expressing cytotoxin alone, induced extensive epithelial damage but little inflammatory reaction. Loss of the mucin layer was not associated with a cytotoxic phenotype, since this loss was observed in mice treated with crude extracts of all strains. The pathogenic roles of CagA, cytotoxin, and urease were further assessed by using extracts of mutant strains of H. pylori defective in the expression of each of these virulence factors. The results obtained suggest that (i) urease activity does not play a significant role in inducing the observed gastric damage, (ii) cytotoxin has an important role in the induction of gastric epithelial cell lesions but not in eliciting inflammation, and (iii) other components present in strains which carry the cagA gene, but distinct from CagA itself, are involved in eliciting the inflammatory response.

A sensitive impedance biosensor based on immunomagnetic separation and urease catalysis for rapid detection of Listeria monocytogenes using an immobilization-free interdigitated array microelectrode.

Science.gov (United States)

Chen, Qi; Lin, Jianhan; Gan, Chengqi; Wang, Yuhe; Wang, Dan; Xiong, Yonghua; Lai, Weihua; Li, Yuntao; Wang, Maohua

2015-12-15

In this study, we described a novel impedance biosensor combining immunomagnetic separation with urease catalysis for sensitive detection of foodborne bacteria using Listeria monocytogenes as model and an immobilization-free microelectrode as detector. The monoclonal antibodies (MAbs) were immobilized on the surface of the magnetic nanoparticles (MNPs) with the diameter of 180 nm by biotin-streptavidin system for specifically and efficiently separating Listeria cells from sample background. The polyclonal antibodies (PAbs) and the urease were modified onto the surface of the gold nanoparticles (AuNPs) with the diameter of 20 nm and the modified AuNPs were used to react with Listera to form the MNP-MAb-Listeria-PAb-AuNP-urease sandwich complexes. The urease in the complexes could catalyze the hydrolysis of the urea into ammonium carbonate and this led to an increase in the ionic strength of the media, which could be detected by the microelectrode. The magnetic separation efficiencies for L. monocytogenes at the concentrations ranging from 3.0×10(1) to 3.0×10(4) CFU/mL were over 95% for the pure cultures and over 85% for the spiked lettuce samples. The lower detection limit of this biosensor for L. monocytogenes was found to be 300 CFU/mL in both the pure cultures and the spiked lettuce samples. The microelectrode was demonstrated to be reusable for over 50 times with thorough cleaning by deionized water. This biosensor showed its potential to provide a simple, low-cost and sensitive method for rapid screening of foodborne pathogens and could be extended for detection of other biological or chemical targets. Copyright © 2015 Elsevier B.V. All rights reserved.

Edwardsiella ictaluri Encodes an Acid Activated Urease that is Required for Intracellular Replication in Channel Catfish Ictalurus punctatus Macrophages

Science.gov (United States)

Genomic analysis indicated that Edwardsiella ictaluri encodes a putative ureasepathogenicity island containing 9 open reading frames, including urea and ammonium transporters. In vitro studies with the wild-type E. ictaluri and a ureG::kan urease mutant strain indicated that E. ictaluri is significa...

Investigating the processes of ammonia exchanges between the atmosphere and a corn canopy following Urea Ammonium Nitrate (UAN) fertilization with urease inhibitor NBPT

Science.gov (United States)

Lichiheb, N.; Myles, L.; Buban, M.; Heuer, M.; Nelson, A. J.; Koloutsou-Vakakis, S.; Rood, M. J.

2017-12-01

Agriculture is the main source of atmospheric emission of ammonia (NH3). The impact of these emissions on air quality is a rising subject of concern in the U.S. due to their adverse effect on human health and the environment. Emissions of NH3 from fertilized crop land occur as soon as fertilizer is applied on the farmed surface and emission can last from a few days to several weeks, depending on the properties of the specific fertilizer and environmental conditions. Because of the variability of these conditions, spatial and temporal variability of NH3 emissions is also variable and uncertain. Therefore, measurement of NH3 emissions is important for understanding the variables affecting the magnitude and temporal distribution of NH3 from fertilized fields. The aim of this study is to investigate the magnitude and the temporal characteristics of NH3 emission over a corn canopy fertilized with UAN and urease inhibitor NBPT, as well as their dependence on environmental variables. The NH3 fluxes above a corn canopy were measured using the flux-gradient (FG) and relaxed eddy accumulation (REA) methods over a period of approximately 3 months following fertilization in a corn field at the Energy Farm at the University of Illinois at Urbana-Champaign, IL, USA. NH3 fluxes were continuously monitored and averaged over 30 min with the FG method. For REA technique, NH3 fluxes were measured in four-hour periods during mornings and afternoons. During the first month after fertilization, prior to corn emergence and for relatively low LAI (volatilization peaks of 2300 ng Nm2s-1 using FG and 800 ng Nm2s-1 using REA were measured. The behavior of this fertilizer was explained by the urease inhibitor which reduced NH3 volatilization and delayed the time of the maximum rate of loss. This delay allows more time for the UAN to become incorporated into the soil. On the basis of this experimental study, urease inhibitor has a considerable effect on the rate and extent of NH3

Comparison of the white-nose syndrome agent Pseudogymnoascus destructans to cave-dwelling relatives suggests reduced saprotrophic enzyme activity.

Science.gov (United States)

Reynolds, Hannah T; Barton, Hazel A

2014-01-01

White-nose Syndrome (WNS) is an emerging infectious mycosis that has impacted multiple species of North American bats since its initial discovery in 2006, yet the physiology of the causal agent, the psychrophilic fungus Pseudogymnoascus destructans ( = Geomyces destructans), is not well understood. We investigated the ability of P. destructans to secrete enzymes that could permit environmental growth or affect pathogenesis and compared enzyme activity across several Pseudogymnoascus species isolated from both hibernating bats and cave sediments. We found that P. destructans produced enzymes that could be beneficial in either a pathogenic or saprotrophic context, such as lipases, hemolysins, and urease, as well as chitinase and cellulases, which could aid in saprotrophic growth. The WNS pathogen showed significantly lower activity for urease and endoglucanase compared to con-generic species (Pseudogymnoascus), which may indicate a shift in selective pressure to the detriment of P. destructans' saprotrophic ability. Based on the positive function of multiple saprotrophic enzymes, the causal agent of White-nose Syndrome shows potential for environmental growth on a variety of substrates found in caves, albeit at a reduced level compared to environmental strains. Our data suggest that if P. destructans emerged as an opportunistic infection from an environmental source, co-evolution with its host may have led to a reduced capacity for saprotrophic growth.

Comparison of the white-nose syndrome agent Pseudogymnoascus destructans to cave-dwelling relatives suggests reduced saprotrophic enzyme activity.

Directory of Open Access Journals (Sweden)

Hannah T Reynolds

Full Text Available White-nose Syndrome (WNS is an emerging infectious mycosis that has impacted multiple species of North American bats since its initial discovery in 2006, yet the physiology of the causal agent, the psychrophilic fungus Pseudogymnoascus destructans ( = Geomyces destructans, is not well understood. We investigated the ability of P. destructans to secrete enzymes that could permit environmental growth or affect pathogenesis and compared enzyme activity across several Pseudogymnoascus species isolated from both hibernating bats and cave sediments. We found that P. destructans produced enzymes that could be beneficial in either a pathogenic or saprotrophic context, such as lipases, hemolysins, and urease, as well as chitinase and cellulases, which could aid in saprotrophic growth. The WNS pathogen showed significantly lower activity for urease and endoglucanase compared to con-generic species (Pseudogymnoascus, which may indicate a shift in selective pressure to the detriment of P. destructans' saprotrophic ability. Based on the positive function of multiple saprotrophic enzymes, the causal agent of White-nose Syndrome shows potential for environmental growth on a variety of substrates found in caves, albeit at a reduced level compared to environmental strains. Our data suggest that if P. destructans emerged as an opportunistic infection from an environmental source, co-evolution with its host may have led to a reduced capacity for saprotrophic growth.

3D-QSAR Studies on Barbituric Acid Derivatives as Urease Inhibitors and the Effect of Charges on the Quality of a Model.

Science.gov (United States)

Ul-Haq, Zaheer; Ashraf, Sajda; Al-Majid, Abdullah Mohammed; Barakat, Assem

2016-04-30

Urease enzyme (EC 3.5.1.5) has been determined as a virulence factor in pathogenic microorganisms that are accountable for the development of different diseases in humans and animals. In continuance of our earlier study on the helicobacter pylori urease inhibition by barbituric acid derivatives, 3D-QSAR (three dimensional quantitative structural activity relationship) advance studies were performed by Comparative Molecular Field Analysis (CoMFA) and Comparative Molecular Similarity Indices Analysis (CoMSIA) methods. Different partial charges were calculated to examine their consequences on the predictive ability of the developed models. The finest developed model for CoMFA and CoMSIA were achieved by using MMFF94 charges. The developed CoMFA model gives significant results with cross-validation (q²) value of 0.597 and correlation coefficients (r²) of 0.897. Moreover, five different fields i.e., steric, electrostatic, and hydrophobic, H-bond acceptor and H-bond donors were used to produce a CoMSIA model, with q² and r² of 0.602 and 0.98, respectively. The generated models were further validated by using an external test set. Both models display good predictive power with r²pred ≥ 0.8. The analysis of obtained CoMFA and CoMSIA contour maps provided detailed insight for the promising modification of the barbituric acid derivatives with an enhanced biological activity.

3D-QSAR Studies on Barbituric Acid Derivatives as Urease Inhibitors and the Effect of Charges on the Quality of a Model

Directory of Open Access Journals (Sweden)

Zaheer Ul-Haq

2016-04-01

Full Text Available Urease enzyme (EC 3.5.1.5 has been determined as a virulence factor in pathogenic microorganisms that are accountable for the development of different diseases in humans and animals. In continuance of our earlier study on the helicobacter pylori urease inhibition by barbituric acid derivatives, 3D-QSAR (three dimensional quantitative structural activity relationship advance studies were performed by Comparative Molecular Field Analysis (CoMFA and Comparative Molecular Similarity Indices Analysis (CoMSIA methods. Different partial charges were calculated to examine their consequences on the predictive ability of the developed models. The finest developed model for CoMFA and CoMSIA were achieved by using MMFF94 charges. The developed CoMFA model gives significant results with cross-validation (q2 value of 0.597 and correlation coefficients (r2 of 0.897. Moreover, five different fields i.e., steric, electrostatic, and hydrophobic, H-bond acceptor and H-bond donors were used to produce a CoMSIA model, with q2 and r2 of 0.602 and 0.98, respectively. The generated models were further validated by using an external test set. Both models display good predictive power with r2pred ≥ 0.8. The analysis of obtained CoMFA and CoMSIA contour maps provided detailed insight for the promising modification of the barbituric acid derivatives with an enhanced biological activity.

Preparation, characterization and application of urease nanoparticles for construction of an improved potentiometric urea biosensor.

Science.gov (United States)

Jakhar, Seema; Pundir, C S

2018-02-15

The nanoparticles (NPs) aggregates of commercial urease from jack beans (Canavalia ensiformis) were prepared by desolvation and glutaraldehyde crosslinking and functionalized by cysteamine dihydrochloride. These enzyme nanoparticles (ENPs) were characterized by transmission electron microscopy (TEM), UV and Fourier transform infrared (FTIR) spectroscopy. The TEM images of urease NPs showed their size in the range, 18-100nm with an average of 51.2nm. The ENPs were more active and stable with a longer shelf life than native enzyme molecules. The ENPs were immobilized onto chitosan (CHIT) activated nitrocellulose (NC) membrane via glutaraldehyde coupling with 32.22% retention of initial activity of free ureaseNPs with a conjugation yield of 1.63mg/cm 2 . This NC membrane was mounted at the lower/sensitive end of the ammonium ion selective electrode (AISE) with O-ring and then electrode was connected to a digital pH meter to construct a potentiometric urea biosensor. The biosensor exhibited optimum response within 10s at pH 5.5and 40°C. The biosensor was employed for measurement of potentiometric determination of urea in sera of apparently healthy and persons suffering from kidney disorders. The biosensor displayed a low detection limit of 1µM/L with a wide working range of 2-80µM/L (0.002-0.08mM) and sensitivity of 23mV/decade. The analytical recovery of added urea in serum was 106.33%. The within and between-batch coefficient of variations (CVs) of present biosensor were 0.18% and 0.32% respectively. There was a good correlation (r = 0.99) between sera urea values obtained by reference method (Enzymic colorimetric kit method) and the present biosensor. The biosensor had negligible interference from Na + ,K + ,NH +4 and Ca 2+ but Mg 2+ ,Cu 2+ and ascorbic acid but had slight interference, which was overcome by specific ion selective electrode. The ENPs bound NC membrane was used maximally 8-9 times per day over a period of 180 days, when stored in 0.01M sodium

Detection of Helicobacter Pylori Genome with an Optical Biosensor Based on Hybridization of Urease Gene with a Gold Nanoparticles-Labeled Probe

Science.gov (United States)

Shahrashoob, M.; Mohsenifar, A.; Tabatabaei, M.; Rahmani-Cherati, T.; Mobaraki, M.; Mota, A.; Shojaei, T. R.

2016-05-01

A novel optics-based nanobiosensor for sensitive determination of the Helicobacter pylori genome using a gold nanoparticles (AuNPs)-labeled probe is reported. Two specific thiol-modified capture and signal probes were designed based on a single-stranded complementary DNA (cDNA) region of the urease gene. The capture probe was immobilized on AuNPs, which were previously immobilized on an APTES-activated glass, and the signal probe was conjugated to different AuNPs as well. The presence of the cDNA in the reaction mixture led to the hybridization of the AuNPs-labeled capture probe and the signal probe with the cDNA, and consequently the optical density of the reaction mixture (AuNPs) was reduced proportionally to the cDNA concentration. The limit of detection was measured at 0.5 nM.

Syntheses of 4,6-dihydroxypyrimidine diones, their urease inhibition, in vitro, in silico, and kinetic studies.

Science.gov (United States)

Muhammad, Munira Taj; Khan, Khalid Mohammed; Arshia; Khan, Ajmal; Arshad, Fiza; Fatima, Bibi; Choudhary, M Iqbal; Syed, Naima; Moin, Syed Tarique

2017-12-01

A library of 4,6-dihydroxypyrimidine diones (1-35) were synthesized and evaluated for their urease inhibitory activity. Structure-activity relationships, and mechanism of inhibition were also studied. All compounds were found to be active with IC 50 values between 22.6±1.14-117.4±0.73µM, in comparison to standard, thiourea (IC 50 =21.2±1.3µM). Kinetics studies on the most active compounds 2-7, 16, 17, 28, and 33 were performed to investigate their modes of inhibition, and dissociation constants K i . Compounds 2, 3, 7, 16, 28, and 33 were found to be mixed-type of inhibitors with K i values in the range of 7.91±0.024-13.03±0.013µM, whereas, compounds 4-6, and 17 were found to be non-competitive inhibitors with K i values in the range of 9.28±0.019-13.05±0.023µM. In silico study was also performed, and a good correlation was observed between experimental and docking studies. This study is continuation of our previously reported urease inhibitory activity of pyrimidine diones, representing potential leads for further research as possible treatment of diseases caused by ureolytic bacteria. Copyright © 2017. Published by Elsevier Inc.

Urease inhibitory isoflavonoids from different parts of Calopogonium mucunoides (Fabaceae).

Science.gov (United States)

Ndemangou, Brigitte; Sielinou, Valerie Tedjon; Vardamides, Juliette Catherine; Ali, Muhammad Shaiq; Lateef, Mehreen; Iqbal, Lubna; Afza, Nigaht; Nkengfack, Augustin Ephrem

2013-12-01

The dichloromethane-methanol (1:1) soluble part of Calopogonium mucunoides (Fabaceae) resulted in the isolation of 10 isoflavones (4'-O-methylalpinumisoflavone, 4'-O-methylderrone, alpinumisoflavone, daidzeine, Calopogonium isoflavone A, atalantoflavone, 2',4',5',7-tetramethoxyisoflavone, 7-O-methylcuneantin, cabreuvin and 7-O-methylpseudobaptigenin) and a rotenoid (6a,12a-dehydroxydegueline). Among these, daidzeine, 7-O-methylcuneantin, atalantoflavone and 6a, 12a-dehydroxydegueline have been isolated for the first time from C. mucunoides while remaining are already reported from this source. Structures of all the isolated constituents were elucidated with the aid of NMR spectroscopic and mass spectrometric techniques. Among all the isolated constituents, nine were evaluated for their urease inhibitory potential. However, six were found potent. These include 4'-O-methylderrone, daidzeine, atalantoflavone, 2',4',5',7-tetramethoxyisoflavone, 7-O-methylcuneantin and 6a, 12a-dehydroxydegueline.

An expedient synthesis of N-(1-(5-mercapto-4-((substituted benzylidene)amino)-4H-1,2,4-triazol-3-yl)-2-phenylethyl)benzamides as jack bean urease inhibitors and free radical scavengers: Kinetic mechanism and molecular docking studies.

Science.gov (United States)

Saeed, Aamer; Larik, Fayaz Ali; Channar, Pervaiz Ali; Mehfooz, Haroon; Ashraf, Mohammad Haseeb; Abbas, Qamar; Hassan, Mubashir; Seo, Sung-Yum

2017-11-01

In this study, some new azomethine-triazole hybrids 5a-5l derived from N-benzoyl-L-phenylalanine were synthesized and characterized. The synthesized compounds showed first-rate, urease inhibition, and compounds 5c and 5e were found to be most effective inhibitors with 0.0137 ± 0.00082 μm and 0.0183 ± 0.00068 μm, respectively (thiourea 15.151 ± 1.27 μm). The kinetic mechanism of urease inhibition revealed the compounds 5c and 5e to be non-competitive inhibitors, whereas compounds 5d and 5j were found to be of mixed-type inhibitors. Docking studies also indicated better interaction patterns with urease enzyme. The results of enzyme inhibition, kinetic mechanism and molecular docking suggest that these compounds can serve as lead compounds in the design of more effective urease inhibitors. © 2017 John Wiley & Sons A/S.

A Portable Low-Power Acquisition System with a Urease Bioelectrochemical Sensor for Potentiometric Detection of Urea Concentrations.

Science.gov (United States)

Ma, Wei-Jhe; Luo, Ching-Hsing; Lin, Jiun-Ling; Chou, Sin-Houng; Chen, Ping-Hung; Syu, Mei-Jywan; Kuo, Shin-Hung; Lai, Shin-Chi

2016-04-02

This paper presents a portable low-power battery-driven bioelectrochemical signal acquisition system for urea detection. The proposed design has several advantages, including high performance, low cost, low-power consumption, and high portability. A LT1789-1 low-supply-voltage instrumentation amplifier (IA) was used to measure and amplify the open-circuit potential (OCP) between the working and reference electrodes. An MSP430 micro-controller was programmed to process and transduce the signals to the custom-developed software by ZigBee RF module in wireless mode and UART in able mode. The immobilized urease sensor was prepared by embedding urease into the polymer (aniline-co-o-phenylenediamine) polymeric matrix and then coating/depositing it onto a MEMS-fabricated Au working electrode. The linear correlation established between the urea concentration and the potentiometric change is in the urea concentrations range of 3.16 × 10(-4) to 3.16 × 10(-2) M with a sensitivity of 31.12 mV/log [M] and a precision of 0.995 (R² = 0.995). This portable device not only detects urea concentrations, but can also operate continuously with a 3.7 V rechargeab-le lithium-ion battery (500 mA·h) for at least four days. Accordingly, its use is feasible and even promising for home-care applications.

HPLC-DAD analysis, antioxidant potential and anti-urease activity of Asparagus gracilis collected from District Islamabad.

Science.gov (United States)

Shah, Naseer Ali; Khan, Muhammad Rashid; Sattar, Saadia; Ahmad, Bushra; Mirza, Bushra

2014-09-23

Asparagus gracilis subspecie of Asparagus capitatus Baker, is described as food and medicine for various ailments. In this study we investigated, its phenolic constituents, in vitro antioxidant potential against various free radicals and anti-urease potential. Asparagus gracilis aerial parts collected from District Islamabad, Pakistan were extracted with crude methanol which was further fractionated into n-hexane, ethyl acetate, n-butanol and aqueous fraction. Total phenolic and flavonoid contents were estimated for extract and all the derived fractions. Diverse in vitro antioxidants assays such as DPPH, H2O2, •OH, ABTS, β-carotene bleaching assay, superoxide radical, lipid peroxidation, reducing power, and total antioxidant capacity were studied to assess scavenging potential. Antiurease activity of methanol extract and its derived fractions was also investigated. HPLC-DAD analysis of crude methanol extract was performed by using different phenolic standards. Ethyl acetate fraction expressed maximum content of flavonoids (240.6 ± 6.1 mg RE/g dry sample), phenolics (615 ± 13 mg GAE/g dry sample) and best antioxidant potential among different fractions of crude methanol extract. Hydrogen peroxide assay and hydroxyl, supeoxide, nitric oxide free radicals antioxidant assays as well as beta carotene assay showed significant correlation with flavonoid content while hydrogen peroxide, ABTS and lipid peroxidation assay displayed significant correlation with phenolic content. HPLC analysis showed the presence of important phenolics i.e. catechin (4.04 ± 0.02 μg/mg sample), caffeic acid (0.89 ± 0.003 μg/mg sample), rutin (24.58 ± 0.1 μg/mg sample), myricetin (1.13 ± 0.07 μg/mg sample) and quercetin (14.91 ± 0.09 μg/mg sample). Ethyl acetate fraction expressed lowest IC50 in antiurease activity. Correlation analysis of antiurease activity expressed significant correlation with flavonoids (P < 0.004) and phenolics (P < 0.02) proposing multipotent activity of

A Urea Biosensor from Stacked Sol-Gel Films with Immobilized Nile Blue Chromoionophore and Urease Enzyme

OpenAIRE

Alqasaimeh, Muawia Salameh; Heng, Lee Yook; Ahmad, Musa

2007-01-01

An optical urea biosensor was fabricated by stacking several layers of sol-gel films. The stacking of the sol-gel films allowed the immobilization of a Nile Blue chromoionophore (ETH 5294) and urease enzyme separately without the need of any chemical attachment procedure. The absorbance response of the biosensor was monitored at 550 nm, i.e. the deprotonation of the chromoionophore. This multi-layer sol-gel film format enabled higher enzyme loading in the biosensor to be achieved. The urea op...

Inhibition of Urease Enzyme Production and some Other Virulence Factors Expression in Proteus mirabilis by N-Acetyl Cysteine and Dipropyl Disulphide.

Science.gov (United States)

Abdel-Baky, Rehab Mahmoud; Ali, Mohamed Abdullah; Abuo-Rahma, Gamal El-Din Ali A; AbdelAziz, Neveen

2017-01-01

Proteus mirabilis is one of the important pathogens that colonize the urinary tract and catheters resulting in various complications, such as blockage of the catheters and the formation of infective stones. In this study we evaluated the effect of N-acetyl cysteine (NAC) and dipropyl disulphide on some virulence factors expressed by a Proteus mirabilis strain isolated from a catheterized patient. Antibacterial activity of both compounds was determined by broth microdilution method. Their effect on different types of motility was determined by LB medium with variable agar content and sub-MIC of each drug. Their effect on adherence and mature biofilms was tested by tissue culture plate assay. Inhibitory effect on urease production was determined and supported by molecular docking studies. The minimum inhibitory concentration (MIC) of NAC and dipropyl disulphide was 25 mM and 100 mM, respectively. Both compounds decreased the swarming ability and biofilm formation of the tested isolate in a dose-dependent manner. NAC had higher urease inhibitory activity (IC50 249 ±0.05 mM) than that shown by dipropyl disulphide (IC 50 10±0.2 mM). Results were supported by molecular docking studies which showed that NAC and dipropyl disulphide interacted with urease enzyme with binding free energy of -4.8 and -8.528 kcal/mol, respectively. Docking studies showed that both compounds interacted with Ni ion and several amino acids (His-138, Gly-279, Cysteine-321, Met-366 and His-322) which are essential for the enzyme activity. NAC and dipropyl disulphide could be used in the control of P. mirabilis urinary tract infections.

Enzymatic, urease-mediated mineralization of gellan gum hydrogel with calcium carbonate, magnesium-enriched calcium carbonate and magnesium carbonate for bone regeneration applications

DEFF Research Database (Denmark)

Douglas, Timothy E L; Łapa, Agata; Samal, Sangram Keshari

2017-01-01

enzymatically with CaCO3 , Mg-enriched CaCO3 and magnesium carbonate to generate composite biomaterials for bone regeneration. Hydrogels loaded with the enzyme urease were mineralized by incubation in mineralization media containing urea and different ratios of calcium and magnesium ions. Increasing...

A Portable Low-Power Acquisition System with a Urease Bioelectrochemical Sensor for Potentiometric Detection of Urea Concentrations

Science.gov (United States)

Ma, Wei-Jhe; Luo, Ching-Hsing; Lin, Jiun-Ling; Chou, Sin-Houng; Chen, Ping-Hung; Syu, Mei-Jywan; Kuo, Shin-Hung; Lai, Shin-Chi

2016-01-01

This paper presents a portable low-power battery-driven bioelectrochemical signal acquisition system for urea detection. The proposed design has several advantages, including high performance, low cost, low-power consumption, and high portability. A LT1789-1 low-supply-voltage instrumentation amplifier (IA) was used to measure and amplify the open-circuit potential (OCP) between the working and reference electrodes. An MSP430 micro-controller was programmed to process and transduce the signals to the custom-developed software by ZigBee RF module in wireless mode and UART in able mode. The immobilized urease sensor was prepared by embedding urease into the polymer (aniline-co-o-phenylenediamine) polymeric matrix and then coating/depositing it onto a MEMS-fabricated Au working electrode. The linear correlation established between the urea concentration and the potentiometric change is in the urea concentrations range of 3.16 × 10−4 to 3.16 × 10−2 M with a sensitivity of 31.12 mV/log [M] and a precision of 0.995 (R2 = 0.995). This portable device not only detects urea concentrations, but can also operate continuously with a 3.7 V rechargeab-le lithium-ion battery (500 mA·h) for at least four days. Accordingly, its use is feasible and even promising for home-care applications. PMID:27049390

A Portable Low-Power Acquisition System with a Urease Bioelectrochemical Sensor for Potentiometric Detection of Urea Concentrations

Directory of Open Access Journals (Sweden)

Wei-Jhe Ma

2016-04-01

Full Text Available This paper presents a portable low-power battery-driven bioelectrochemical signal acquisition system for urea detection. The proposed design has several advantages, including high performance, low cost, low-power consumption, and high portability. A LT1789-1 low-supply-voltage instrumentation amplifier (IA was used to measure and amplify the open-circuit potential (OCP between the working and reference electrodes. An MSP430 micro-controller was programmed to process and transduce the signals to the custom-developed software by ZigBee RF module in wireless mode and UART in able mode. The immobilized urease sensor was prepared by embedding urease into the polymer (aniline-co-o-phenylenediamine polymeric matrix and then coating/depositing it onto a MEMS-fabricated Au working electrode. The linear correlation established between the urea concentration and the potentiometric change is in the urea concentrations range of 3.16 × 10−4 to 3.16 × 10−2 M with a sensitivity of 31.12 mV/log [M] and a precision of 0.995 (R2 = 0.995. This portable device not only detects urea concentrations, but can also operate continuously with a 3.7 V rechargeab-le lithium-ion battery (500 mA·h for at least four days. Accordingly, its use is feasible and even promising for home-care applications.

A dip-and-read test strip for the determination of mercury(II) ion in aqueous samples based on urease activity inhibition.

Science.gov (United States)

Shi, Guo-Qing; Jiang, Guibin

2002-11-01

A sensitive dip-and-read test strip for the determination of mercury in aqueous samples based on the inhibition of urease reaction by the ion has been developed. The strip has a circular sensing zone that containing two layers: the top layer is a cellulose acetate membrane where urease is immobilized on it; the bottom layer is a pH indicator wafer that is impregnated with urea. The principle of the measurement is based on the disappearance of a yellow spot on the pH indicator wafer. The elapsing time until the disappearance of the spot which depends on the concentration of mercury(II) ion is measured with a stopwatch. Under the experimental conditions, as low as 0.2 ng/ml mercury can be observed with the detection range from 0.2 to 200 ng/ml in water. Organomercury compounds give essentially the same response as inorganic mercury. Heavy-metal ions such as Ag(I), Cu(II), Cd(II), Ni(II), Zn(II), and Pb(II) as well as other sample matrixes basically do not interfere with the mercury measurement.

Heat-treatment reduces anti-nutritional phytochemicals and maintains protein quality in genetically improved hulled soybean flour

Directory of Open Access Journals (Sweden)

Ariela Werneck de Carvalho

2013-06-01

Full Text Available The soybean is a protein source of high biological value. However, the presence of anti-nutritional factors affects its protein quality and limits the bioavailability of other nutrients. The effect of heat-treatment, 150 ºC for 30 minutes, on hulled and hull-less soybean flour from the cultivar UFVTN 105AP on urease, trypsin inhibitor activity, protein solubility, amino acid profile, and in vivo protein quality was investigated. The treatment reduced the trypsin inhibitor activity and urease, but it did not affect protein solubility. Protein Efficiency Coefficient (PER values of the flours were similar, and the PER of the hull-less soybean flour did not differ from casein. The Net Protein Ratio (NPR did not differ between the experimental groups. The True Digestibility (TD of the flours did not differ, but both were lower in casein and the Protein Digestibility Corrected Amino Acid Score (PDCCAS was lower than the TD, due to limited valine determined by the chemical score. Therefore, the flours showed reduced anti-nutritional phytochemicals and similar protein quality, and therefore the whole flours can be used as a source of high quality protein.

Nitrogen Control in Pseudomonas aeruginosa : A Role for Glutamine in the Regulation of the Synthesis of NADP-Dependent Glutamate Dehydrogenase, Urease and Histidase

NARCIS (Netherlands)

Janssen, Dick B.; Herst, Patricia M.; Joosten, Han M.L.J.; Drift, Chris van der

1981-01-01

In Pseudomonas aeruginosa the formation of urease, histidase and some other enzymes involved in nitrogen assimilation is repressed by ammonia in the growth medium. The key metabolite in this process appears to be glutamine or a product derived from it, since ammonia and glutamate did not repress

Synthesis, urease inhibition, antioxidant and antibacterial studies of some 4-amino-5-aryl-3H-1,2,4-triazole-3-thiones and their 3,6-disubstituted 1,2,4-triazolo[3,4-b]1,3,4-thiadiazole derivatives

International Nuclear Information System (INIS)

Hanif, Muhammad; Saleem, Muhammad; Rama, Nasim Hasan; Hussain, Muhammad Tahir; Zaib, Sumera; Aslam, Muhammad Adil M.; Iqbal, Jamshed; Jones, Peter G.

2012-01-01

A new series of 4-amino-5-aryl-3H-1,2,4-triazole-3-thiones, bearing various methoxybenzyl- and methoxyphenethyl groups, was synthesized by refluxing potassium hydrazinecarbodithioate salts in dilute aqueous solution of hydrazine hydrate. These salts were formed by the reaction of acid hydrazides and carbon disulfide in methanolic potassium hydroxide solution at 0-5 deg C. 4-Amino- 5-aryl-3H-1,2,4-triazole-3-thiones were condensed with different substituted aromatic acids to yield 3,6-disubstituted-1,2,4-triazolo[3,4-b]1,3,4-thiadiazoles. The structures of the synthesized compounds were characterized by infrared (IR), 1 H and 13 C nuclear magnetic resonance (NMR), elemental analysis and mass spectrometric (MS) studies. All the synthesized compounds were screened for their urease inhibition, antioxidant and antibacterial activities. Some compounds showed excellent urease inhibition activity, more than the standard drug. Others exhibited potent antioxidant activity. All the compounds showed significant antibacterial activities as compared to the standard drug. (author)

Promotion of osteogenic differentiation of stem cells and increase of bone-bonding ability in vivo using urease-treated titanium coated with calcium phosphate and gelatin

Science.gov (United States)

Huang, Zhong-Ming; Qi, Yi-Ying; Du, Shao-Hua; Feng, Gang; Unuma, Hidero; Yan, Wei-Qi

2013-10-01

Because of its excellent biocompatibility and low allergenicity, titanium has been widely used for bone replacement and tissue engineering. To produce a desirable composite with enhanced bone response and mechanical strength, in this study bioactive calcium phosphate (CaP) and gelatin composites were coated onto titanium (Ti) via a novel urease technique. The cellular responses to the CaP/gelatin/Ti (CaP/gel/Ti) and bone bonding ability were evaluated with proliferation and osteogenic differentiation of mesenchymal stem cells (MSCs) on CaP/gel/Ti and CaP/Ti in vitro. The results showed that the optical density values, alkaline phosphatase expression and genes expression of MSCs on CaP/gel/Ti were similar to those on CaP/Ti, yet significantly higher than those on pure Ti (p layer. An interfacial layer, containing Ti, Ca and P, was found to form at the interface between bone and the implant on all three groups by EDS analysis. However, the content of Ca, P in the surface of CaP/gel/Ti implants was more than in the other two groups at each time point. The CaP/gel/Ti modified by the urease method was not only beneficial for MSCs proliferation and osteogenic differentiation, but also favorable for bone bonding ability on Ti implants in vivo, suggesting that Ti functionalized with CaP and gelatin might have a great potential in clinical joint replacement or dental implants.

Enzyme-polyelectrolyte multilayer assemblies on reduced graphene oxide field-effect transistors for biosensing applications.

Science.gov (United States)

Piccinini, Esteban; Bliem, Christina; Reiner-Rozman, Ciril; Battaglini, Fernando; Azzaroni, Omar; Knoll, Wolfgang

2017-06-15

We present the construction of layer-by-layer (LbL) assemblies of polyethylenimine and urease onto reduced-graphene-oxide based field-effect transistors (rGO FETs) for the detection of urea. This versatile biosensor platform simultaneously exploits the pH dependency of liquid-gated graphene-based transistors and the change in the local pH produced by the catalyzed hydrolysis of urea. The use of an interdigitated microchannel resulted in transistors displaying low noise, high pH sensitivity (20.3µA/pH) and transconductance values up to 800 µS. The modification of rGO FETs with a weak polyelectrolyte improved the pH response because of its transducing properties by electrostatic gating effects. In the presence of urea, the urease-modified rGO FETs showed a shift in the Dirac point due to the change in the local pH close to the graphene surface. Markedly, these devices operated at very low voltages (less than 500mV) and were able to monitor urea in the range of 1-1000µm, with a limit of detection (LOD) down to 1µm, fast response and good long-term stability. The urea-response of the transistors was enhanced by increasing the number of bilayers due to the increment of the enzyme surface coverage onto the channel. Moreover, quantification of the heavy metal Cu 2+ (with a LOD down to 10nM) was performed in aqueous solution by taking advantage of the urease specific inhibition. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Detection of helicobacter pylori in nasal polyps using rapid urease test and ELISA

Directory of Open Access Journals (Sweden)

Masood Kaviani

2009-01-01

Full Text Available Introduction: Nasal polyposis is an inflammatory condition of unknown etiology. Recently concerns regarding gastroesophageal reflux or helicobacter pylori as a possible pathologic cause of nasal polyps have been increasing. The present study was planned to investigate the presence of helicobacter pylori in nasal polyps. Materials and Methods: This case-control study was undertaken enrolling 37 patients with nasal polyps who had undergone nasal endoscopic sinus surgery and 38 control subjects. Biopsy specimens of nasal polyps and inferior turbinates were assessed by rapid urease test. Blood samples of both study and control subjects were evaluated for anti H.pylori IgG by ELISA. H. pylori status was regarded positive, if both tests were positive. Results: Seropositivity was more common in the patients with nasal polyps (66.2% than control subjects (36.8% (P

Nitrogen uptake and balance of the fertilizers urea, urea with urease inhibitor, and ammonium nitrate applied to spring wheat at stem elongation growth stage

International Nuclear Information System (INIS)

Matzel, W.; Lippold, H.; Heber, R.

1979-01-01

The use of urea containing 1% of diamido phosphoric acid phenyl ester, which is a urease inhibitor, for the top dressing of spring wheat on light soil allows the loss of nitrogen due to volatilization of ammonia from urea to be prevented. The urease inhibitor has no effect whatsoever upon the uptake of urea nitrogen by spring wheat. Even in those cases where the volatilization of ammonia is prevented, plants will take up 5 to 6% less nitrogen from urea than from ammonium nitrate. This is due primarily to the higher degree of immobilization of urea nitrogen in the soil. The volatilization of ammonia from urea applied to the surface of the soil was in the region of 25% when the soil surface was moist and 10% when the soil surface was dry, the percentages given above being related to the amount of fertilizer nitrogen applied to the soil. The plant uptake of fertilizer nitrogen applied as a second dose at stem elongation will be complete after two to three weeks or after six weeks under favourable or unfavourable conditions, respectively. Proceeding immediately after application of the fertilizer nitrogen are the processes resulting in both loss of nitrogen and its immobilization. The proportion of absorbed fertilizer nitrogen recovered in the grain will be the greater the later the nitrogen is incorporated into the plant. The use in pot experiments of labelled nitrogen fertilizers enables statistically significant differences in effects to be determined even in those cases in which the differences are only relatively small in degree. (author)

Construction of a simple optical sensor based on air stable lipid film with incorporated urease for the rapid detection of urea in milk.

Science.gov (United States)

Nikoleli, Georgia-Paraskevi; Nikolelis, Dimitrios P; Methenitis, Constantinos

2010-08-18

This work describes the construction of a simple optical sensor for the rapid, selective and sensitive detection of urea in milk using air stable lipid films with incorporated urease. The lipid film is stabilized on a glass filter by polymerization using UV (ultra-violet) radiation prior its use. Methacrylic acid was the functional monomer, ethylene glycol dimethacrylate was the crosslinker and 2,2'-azobis-(2-methylpropionitrile) was the initiator. Urease is incorporated within this mixture prior to the polymerization. The presence of the enzyme in these films quenched this fluorescence and the colour became similar to that of the filters without the lipid films. A drop of aqueous solution of urea provided a "switching on" of the fluorescence which allows the rapid detection of this compound at the levels of 10(-8) M concentrations. The investigation of the effect of potent interferences included a wide range of compounds usually found in foods and also of proteins and lipids. These lipid membranes were used for the rapid detection of urea in milk. Copyright 2010 Elsevier B.V. All rights reserved.

Application of radiation grafted media for lectin affinity separation and urease immobilization: a novel approach to tumor therapy and renal disease diagnosis

International Nuclear Information System (INIS)

Mueller-Schulte, D.; Daschek, W.

1995-01-01

Carriers modified by synergistic radiation grafting are used as affinity media for the separation of a lectin from a mistletoe extract. The grafted supports show distinctly superior properties when compared to conventional affinity media. The application of these carriers as urease immobilization support incorporated in a conductimetric bioreactor for urea analysis as potential diagnostic device in renal diseases is also described. (Author)

5-Bromo-2-aryl benzimidazole derivatives as non-cytotoxic potential dual inhibitors of α-glucosidase and urease enzymes.

Science.gov (United States)

Arshad, Tanzila; Khan, Khalid Mohammed; Rasool, Najma; Salar, Uzma; Hussain, Shafqat; Asghar, Humna; Ashraf, Mohammed; Wadood, Abdul; Riaz, Muhammad; Perveen, Shahnaz; Taha, Muhammad; Ismail, Nor Hadiani

2017-06-01

On the basis of previous report on promising α-glucosidase inhibitory activity of 5-bromo-2-aryl benzimidazole derivatives, these derivatives were further screened for urease inhibitory and cytotoxicity activity in order to get more potent and non-cytotoxic potential dual inhibitor for the patients suffering from diabetes as well as peptic ulcer. In this study, all compounds showed varying degree of potency in the range of (IC 50 =8.15±0.03-354.67±0.19μM) as compared to standard thiourea (IC 50 =21.25±0.15μM). It is worth mentioning that derivatives 7 (IC 50 =12.07±0.05μM), 8 (IC 50 =10.57±0.12μM), 11 (IC 50 =13.76±0.02μM), 14 (IC 50 =15.70±0.12μM) and 22 (IC 50 =8.15±0.03μM) were found to be more potent inhibitors than standard. All compounds were also evaluated for cytotoxicity towards 3T3 mouse fibroblast cell line and found to be completely non-toxic. Previously benzimidazole 1-25 were also showed α-glucosidase inhibitory potential. In silico studies were performed on the lead molecules i.e.2, 7, 8, 11, 14, and 22, in order to rationalize the binding interaction of compounds with the active site of urease enzyme. Copyright © 2017 Elsevier Inc. All rights reserved.

Synthesis, crystal structures, and urease inhibition of an acetohydroxamate-coordinated oxovanadium(V) complex derived from N'-(3-bromo-2-hydroxybenzylidene)-4-methoxybenzohydrazide.

Science.gov (United States)

Qu, Dan; Niu, Fang; Zhao, Xinlu; Yan, Ke-Xiang; Ye, Yu-Ting; Wang, Jia; Zhang, Mei; You, Zhonglu

2015-05-01

A new benzohydrazone compound N'-(3-bromo-2-hydroxybenzylidene)-4-methoxybenzohydrazide (H₂L) was prepared. Reaction of H₂L and acetohydroxamic acid (HAHA) with VO(acac)₂ in methanol gave the complex [VOL(AHA)]. Both H₂L and the oxovanadium complex were characterized by elemental analysis, IR, UV-vis and (1)H NMR spectra, and single crystal X-ray diffraction. H₂L was also characterized by high-resolution mass spectrum. Thermal analysis of the oxovanadium complex was carried out. The benzohydrazone ligand, in its dianionic form, coordinates to V atom through the phenolate oxygen, imino nitrogen and enolate oxygen. The acetohydroxamic acid coordinates to V atom through the carbonyl oxygen and deprotonated hydroxyl oxygen. The V atom is in octahedral coordination. H₂L, HAHA and the oxovanadium complex were tested for their urease inhibitory activities. The percent inhibition at concentration of 100 μmol·L(-1) on Helicobacter pylori urease is 78% for the oxovanadium complex. The IC₅₀ value for the complex is 36.5 μmol·L(-1). Molecular docking study was performed to study the inhibition. Copyright © 2015 Elsevier Ltd. All rights reserved.

Periodontal disease and Helicobacter pylori infection: a community-based study using serology and rapid urease test.

Science.gov (United States)

Nisha, Krishnavilasom J; Nandakumar, Krishnankutty; Shenoy, Kottacherry T; Janam, Presanthila

2016-02-01

The aims of the present study were to assess the prevalence of periodontal disease and Helicobacter pylori (H. pylori) infection and their associations within a predefined Indian population. A community-based cross-sectional study of 500 selected individuals using a questionnaire, oral examination, rapid urease testing of dental plaque, and serological examination for immunoglobulin G antibody to H. pylori was carried out. Periodontal disease and H. pylori infection were prevalent in more than 50% of the population. Age, smoking, and diabetic status of the individuals were risk factors for periodontal disease after multivariate analysis, and a lack of proper sewage and waste disposal facilities were found to increase the risk of H. pylori infection. Although there was no association between periodontal disease and H. pylori seropositivity in the community, a highly-significant association was found between periodontal disease and colonization of H. pylori in dental plaque. Because periodontal disease is associated with the increased colonization of H. pylori, new treatment modalities, such as plaque control measures, should be employed for the complete management of H. pylori-associated gastric disease. © 2014 Wiley Publishing Asia Pty Ltd.

Investigating the Influence of Temperature on the Kaolinite-Base Synthesis of Zeolite and Urease Immobilization for the Potential Fabrication of Electrochemical Urea Biosensors.

Science.gov (United States)

Anderson, David Ebo; Balapangu, Srinivasan; Fleischer, Heidimarie N A; Viade, Ruth A; Krampa, Francis D; Kanyong, Prosper; Awandare, Gordon A; Tiburu, Elvis K

2017-08-08

Temperature-dependent zeolite synthesis has revealed a unique surface morphology, surface area and pore size which influence the immobilization of urease on gold electrode supports for biosensor fabrication. XRD characterization has identified zeolite X (Na) at all crystallization temperatures tested. However, N₂ adsorption and desorption results showed a pore size and pore volume of zeolite X (Na) 60 °C, zeolite X (Na) 70 °C and zeolite X (Na) 90 °C to range from 1.92 nm to 2.45 nm and 0.012 cm³/g to 0.061 cm³/g, respectively, with no significant differences. The specific surface area of zeolite X (Na) at 60, 70 and 90 °C was 64 m²/g, 67 m²/g and 113 m²/g, respectively. The pore size, specific surface area and pore volumes of zeolite X (Na) 80 °C and zeolite X (Na) 100 °C were dramatically increased to 4.21 nm, 295 m²/g, 0.762 cm³/g and 4.92 nm, 389 m²/g, 0.837 cm³/g, in that order. The analytical performance of adsorbed urease on zeolite X (Na) surface was also investigated using cyclic voltammetry measurements, and the results showed distinct cathodic and anodic peaks by zeolite X (Na) 80 °C and zeolite X (Na) 100 °C. These zeolites' molar conductance was measured as a function of urea concentration and gave an average polynomial regression fit of 0.948. The findings in this study suggest that certain physicochemical properties, such as crystallization temperature and pH, are critical parameters for improving the morphological properties of zeolites synthesized from natural sources for various biomedical applications.

Sulfonamide-Linked Ciprofloxacin, Sulfadiazine and Amantadine Derivatives as a Novel Class of Inhibitors of Jack Bean Urease; Synthesis, Kinetic Mechanism and Molecular Docking.

Science.gov (United States)

Channar, Pervaiz Ali; Saeed, Aamer; Albericio, Fernando; Larik, Fayaz Ali; Abbas, Qamar; Hassan, Mubashir; Raza, Hussain; Seo, Sung-Yum

2017-08-16

Sulfonamide derivatives serve as an important building blocks in the drug design discovery and development (4D) process. Ciprofloxacin-, sulfadiazine- and amantadine-based sulfonamides were synthesized as potent inhibitors of jack bean urease and free radical scavengers. Molecular diversity was explored and electronic factors were also examined. All 24 synthesized compounds exhibited excellent potential against urease enzyme. Compound 3e (IC 50 = 0.081 ± 0.003 µM), 6a (IC 50 = 0.0022 ± 0.0002 µM), 9e (IC 50 = 0.0250 ± 0.0007 µM) and 12d (IC 50 = 0.0266 ± 0.0021 µM) were found to be the lead compounds compared to standard (thiourea, IC 50 = 17.814 ± 0.096 µM). Molecular docking studies were performed to delineate the binding affinity of the molecules and a kinetic mechanism of enzyme inhibition was propounded. Compounds 3e , 6a and 12d exhibited a mixed type of inhibition, while derivative 9e revealed a non-competitive mode of inhibition. Compounds 12a , 12b , 12d , 12e and 12f showed excellent radical scavenging potency in comparison to the reference drug vitamin C.

Carbonic Anhydrase and Urease Inhibitory Potential of Various Plant Phenolics Using in vitro and in silico Methods.

Science.gov (United States)

Rauf, Abdur; Raza, Muslim; Saleem, Muhammad; Ozgen, Ufuk; Karaoglan, Esen Sezen; Renda, Gulin; Palaska, Erhan; Orhan, Ilkay Erdogan

2017-06-01

Plant phenolics are known to display many pharmacological activities. In the current study, eight phenolic compounds, e.g., luteolin 5-O-β-glucoside (1), methyl rosmarinate (2), apigenin (3), vicenin 2 (4), lithospermic acid (5), soyasaponin II (6), rubiadin 3-O-β-primeveroside (7), and 4-(β-d-glucopyranosyloxy)benzyl 3,4-dihydroxybenzoate (8), isolated from various plant species were tested at 0.2 mm against carbonic anhydrase-II (CA-II) and urease using microtiter assays. Urease inhibition rate for compounds 1 - 8 ranged between 5.0 - 41.7%, while only compounds 1, 2, and 4 showed a considerable inhibition over 50% against CA-II with the IC 50 values of 73.5 ± 1.05, 39.5 ± 1.14, and 104.5 ± 2.50 μm, respectively, where IC 50 of the reference (acetazolamide) was 21.0 ± 0.12 μm. In silico experiments were also performed through two docking softwares (Autodock Vina and i-GEMDOCK) in order to find out interactions between the compounds and CA-II. Actually, compounds 6 (30.0%) and 7 (42.0%) possessed a better binding capability toward the active site of CA-II. According to our results obtained in this study, among the phenolic compounds screened, particularly 1, 2, and 4 appear to be the promising inhibitors of CA-II and may be further investigated as possible leads for diuretic, anti-glaucoma, and antiepileptic agents. © 2017 Wiley-VHCA AG, Zurich, Switzerland.

The significance of reduced respiratory chain enzyme activities: clinical, biochemical and radiological associations.

Science.gov (United States)

Mordekar, S R; Guthrie, P; Bonham, J R; Olpin, S E; Hargreaves, I; Baxter, P S

2006-03-01

Mitochondrial diseases are an important group of neurometabolic disorders in children with varied clinical presentations and diagnosis that can be difficult to confirm. To report the significance of reduced respiratory chain enzyme (RCE) activity in muscle biopsy samples from children. Retrospective odds ratio was used to compare clinical and biochemical features, DNA studies, neuroimaging, and muscle biopsies in 18 children with and 48 without reduced RCE activity. Children with reduced RCE activity were significantly more likely to have consanguineous parents, to present with acute encephalopathy and lactic acidaemia and/or within the first year of life; to have an axonal neuropathy, CSF lactate >4 mmol/l; and/or to have signal change in the basal ganglia. There were positive associations with a maternal family history of possible mitochondrial cytopathy; a presentation with failure to thrive and lactic acidaemia, ragged red fibres, reduced fibroblast fatty acid oxidation and with an abnormal allopurinol loading test. There was no association with ophthalmic abnormalities, deafness, epilepsy or myopathy. The association of these clinical, biochemical and radiological features with reduced RCE activity suggests a possible causative link.

5-Acetyl-6-methyl-4-aryl-3,4-dihydropyrimidin-2(1H)-ones: As potent urease inhibitors; synthesis, in vitro screening, and molecular modeling study.

Science.gov (United States)

Shamim, Shahbaz; Khan, Khalid Mohammed; Salar, Uzma; Ali, Farman; Lodhi, Muhammad Arif; Taha, Muhammad; Khan, Farman Ali; Ashraf, Sajda; Ul-Haq, Zaheer; Ali, Muhammad; Perveen, Shahnaz

2018-02-01

5-Acetyl-6-methyl-4-aryl-3,4-dihydropyrimidin-2(1H)-ones 1-43 were synthesized in a "one-pot" three component reaction and structurally characterized by various spectroscopic techniques such as 1 H, 13 C NMR, EI-MS, HREI-MS, and IR. All compounds were evaluated for their in vitro urease inhibitory activity. It is worth mentioning that except derivatives 1, 11, 12, and 14, all were found to be more potent than the standard thiourea (IC 50  = 21.25 ± 0.15 µM) and showed their urease inhibitory potential in the range of IC 50  = 3.70 ± 0.5-20.14 ± 0.1 µM. Structure-activity relationship (SAR) was rationalized by looking at the varying structural features of the molecules. However, molecular modeling study was performed to confirm the binding interactions of the molecules (ligand) with the active site of enzyme. Copyright © 2017 Elsevier Inc. All rights reserved.

The effect of sub-inhibitory concentrations of rifaximin on urease production and on other virulence factors expressed by Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa and Staphylococcus aureus.

Science.gov (United States)

Ricci, Annalisa; Coppo, Erika; Barbieri, Ramona; Debbia, Eugenio A; Marchese, Anna

2017-04-01

Rifaximin, a topical derivative of rifampin, inhibited urease production and other virulence factors at sub-MIC concentrations in strains involved in hepatic encephalopathy and the expression of methicillin resistance in Staphylococcus aureus. In particular, urease production was affected in all Proteus mirabilis and Klebsiella pneumoniae strains as well as in all tested Pseudomonas aeruginosa isolates. Other exotoxins, synthesized by P. aeruginosa, such as protease, gelatinase, lipase, lecithinase and DNAse were also not metabolized in the presence of rifaximin. This antibiotic inhibited pigment production in both P. aeruginosa and Chromobacterium violaceum, a biosensor control strain. Lastly, rifaximin affected haemolysin production in S. aureus and was able to restore cefoxitin susceptibility when the strain was cultured in the presence of sub-MICs of the drug. The present findings confirm and extend previous observations about the beneficial effects of rifaximin for the treatment of gastrointestinal diseases, since in this anatomic site, it reaches a large array of concentrations which prevents enterobacteria from thriving and/or producing their major virulence factors.

Four-phonon scattering significantly reduces intrinsic thermal conductivity of solids

Science.gov (United States)

Feng, Tianli; Lindsay, Lucas; Ruan, Xiulin

2017-10-01

For decades, the three-phonon scattering process has been considered to govern thermal transport in solids, while the role of higher-order four-phonon scattering has been persistently unclear and so ignored. However, recent quantitative calculations of three-phonon scattering have often shown a significant overestimation of thermal conductivity as compared to experimental values. In this Rapid Communication we show that four-phonon scattering is generally important in solids and can remedy such discrepancies. For silicon and diamond, the predicted thermal conductivity is reduced by 30% at 1000 K after including four-phonon scattering, bringing predictions in excellent agreement with measurements. For the projected ultrahigh-thermal conductivity material, zinc-blende BAs, a competitor of diamond as a heat sink material, four-phonon scattering is found to be strikingly strong as three-phonon processes have an extremely limited phase space for scattering. The four-phonon scattering reduces the predicted thermal conductivity from 2200 to 1400 W/m K at room temperature. The reduction at 1000 K is 60%. We also find that optical phonon scattering rates are largely affected, being important in applications such as phonon bottlenecks in equilibrating electronic excitations. Recognizing that four-phonon scattering is expensive to calculate, in the end we provide some guidelines on how to quickly assess the significance of four-phonon scattering, based on energy surface anharmonicity and the scattering phase space. Our work clears the decades-long fundamental question of the significance of higher-order scattering, and points out ways to improve thermoelectrics, thermal barrier coatings, nuclear materials, and radiative heat transfer.

Utilization of C-14 settled urease for diagnosing Campylobacter Pylori in the stomach

International Nuclear Information System (INIS)

Chausson, Y.; Coelho, L.G.V.

1990-01-01

A new method for diagnosing the Campylobacter Pylori in the stomach is described, using C-14 settled urease. Campylobacter Pylori is now being considered the most probable causative agent of antral chronic gastritis, pepitic ulcer and non-ulcerous dyspepsia. The technique is based on ingestion of the tracer, its recovery by exhalation in etanol hyamine solution, followed by counting and dates evaluation. The test was applied to forty two voluntary male and female patients, after their written acquiescence. Their ages varied from 19 to 62 years old. Thirty of the results were positive and twelve negative. All of them were comproved by microbiological (cultura) and hystologycal studies of gastric biopsy gotten by gastroscopy. They were performed at the Gastroentherology Departament of the 'Hospital das Clinicas' that belongs to the Federal University of Minas Gerais. Repetitivity of the breath test was confirmed by repetition of the results in five positive patients and five negative ones. (author) [pt

A facile synthesis of new 5-aryl-thiophenes bearing sulfonamide moiety via Pd(0-catalyzed Suzuki–Miyaura cross coupling reactions and 5-bromothiophene-2-acetamide: As potent urease inhibitor, antibacterial agent and hemolytically active compounds

Directory of Open Access Journals (Sweden)

Mnaza Noreen

2017-01-01

Full Text Available The present study reports a convenient approach for the synthesis of thiophene sulfonamide derivatives (3a–3k via Suzuki cross coupling reaction. This method of synthesis involved the reactions of various aryl boronic acids and esters with 5-bromthiophene-2-sulfonamide (2 under mild and suitable temperature conditions. The compounds synthesized in the present study were subjected to urease inhibition and hemolytic activities. The substitution pattern and the electronic effects of different functional groups (i.e., Cl, CH3, OCH3, F etc. available on the aromatic ring are found to have significant effect on the overall results. The compound 5-Phenylthiophene-2-sulfonamide 3a showed the highest urease inhibition activity with IC50 value ∼ 30.8 μg/mL compared with the thiourea (used as standard having IC50 value ∼ 43 μg/mL. Moreover, almost all of the compounds were examined for the hemolytic activity against triton X-100 with positive results obtained in most of the cases. In addition, the antibacterial activities of the derivatives of 5-arylthiophene-2-sulfonamide and 5-bromothiophene-2-acetamide were also investigated during the course of the study.

Urease activity and its relation to soil organic matter, microbial biomass nitrogen and urea-nitrogen assimilation by maize in a Brazilian oxisol under no-tillage and tillage systems

NARCIS (Netherlands)

Roscoe, R.; Vasconcellos, C.A.; Furtini Neto, A.E.; Guedes, G.A.A.; Fernandes, L.A.

2000-01-01

We studied the relationship between urease activity (UA) and soil organic matter (SOM), microbial biomass N (Nbiom) content, and urea-N fertilizer assimilation by maize in a Dark Red Latosol (Typic Haplustox) cultivated for 9 years under no-tillage (NT), tillage with a disc plough (DP), and tillage

Changes in Protein Content and Urease Activity Due to Soaking Treatment of gamma irradiated Soybean Seeds

International Nuclear Information System (INIS)

Kamel, H.A.; Aly, M.A.S.; Afifi, M.L.

2003-01-01

The total protein measurement revealed that both soaking time and radiation affected protein content of soybean seeds. Amount of protein content increased gradually with time up to 6 h. The amount recorded 388, 396 and 465 mg/g.d.wt in control, 10, 25, 50 Gy, respectively. Then the amount decreased at and 24 h whereas, protein content of cotyledonary leaves (120 h) increased by 25 and 50 Gy reaching 7305 and 80.6 mg/g.d.wt as compared to 68.5 mg/g.d wt in case on control. On comparison with control samples, 10 Gy appeared to have no effect on protein content while 25 and 50 Gy increased protein in a dose dependant matter. Maximum increase in urease activity was recorded at 6 h of soaking (1110, 1162 and 1200 unit/g f.wt in control, 10, 25 and 50 Gy respectively) Moreover, the 25 and 50 Gy increased urease activity at all time intervals. After sodium dodecyl sulfate- polyacrylamide gel electrophoresis (SDS-PAGE) was applied, bands could be segregated into high molecular weight bands they are represented from band No 1 with 200 KDa to band No 8 with 100 kDa. On the other hand low molecular weight are presented from band No 9 with 75 kDa to band No 14 with 10 kDa. Characteristic bands No 4 and 10 were common in all samples and several other bands were characteristic to the time or gamma-radiation applied. Calculated similarity index (SI) showed similarity between control and 25 Gy treated samples (except at 6 h). In contrast, the similarity index between control and 50 Gy decreased from zero up to 6 h then increased to 1 at 120 h (the same trend was also observed between 25 and 50 Gy). From similarity index study it could be concluded that at cotyledonary stage(120 h) there were no differences between different samples, thus indicating a recovery from the effect of gamma irradiation

Effect of the urease inhibitor phosphoric acid phenyl ester diamide on the utilization of urea-N in top dressing of spring wheat and oats

International Nuclear Information System (INIS)

Matzel, W.; Mueller, S.; Lippold, H.; Heber, R.

1979-01-01

In pot experiments with spring wheat and oats the application of the urease inhibitor phosphoric acid phenyl ester diamide (PPDA) in addition to top dressing with 15 N-urea revealed a 10% better utilization of the 15 N-urea by the plant (related to the N amount applied). The loss-reducing effect of PPDA was especially felt when there were favourable conditions for NH 3 volatilization such as rapid hydrolysis of urea on the wet surface of light soil during shooting of the wheat. PPDA did not have any adverse influence on the course of the nitrogen uptake by the cereals during the time of shooting from the urea applied in top dressing. The utilization of the urea-N by the wheat, being about 5 to 6% lower in comparison to ammonium nitrate, under conditions that do not allow NH 3 losses, is to be attributed to the increased immobilization of the urea-N in the soil. The processes responsible for the nitrogen losses were concluded 3 to 4 weeks after top dressing to the cereals during the shooting period. (author)

Development of a ratiometric fluorescent urea biosensor based on the urease immobilized onto the oxazine 170 perchlorate-ethyl cellulose membrane.

Science.gov (United States)

Dinh Duong, Hong; Il Rhee, Jong

2015-03-01

In this work, the oxazine 170 perchlorate (O17)-ethyl cellulose (EC) membrane was successfully applied in the fabrication of a urea-sensing membrane. The urea-sensing membrane was a double layer consisting of the O17-EC membrane and a layer of the enzyme urease entrapped into EC matrix. The sensing principle of urea was based on the hydrolysis reaction of urea under the catalysis of the urease to produce ammonia in water and also on the binding of ammonia with the dye O17 to create the shift in the emission wavelength from λ(em)=630 nm to λ(em)=565 nm. The data collected from the ratio of the fluorescence intensities at λ(em)=630 nm and λ(em)=565 nm was proportional to urea concentration. The urea-sensing membrane with the ratiometric method was used to measure the concentrations of urea in the range of 0.01-0.1 M with a limit of detection (LOD) of 0.027 mM and 0.1-1.0 M with LOD of 0.224 mM. It showed fast response time, high reversibility and long-term stability in this concentration range. The recovery percentage of urea concentrations of the urea-sensing membrane for two kinds of biological urine solutions (BU1, BU2) was around 85-118%. The measured results were in good agreement with standard urea concentrations in the range of 0.06 M to 1.0 M. Copyright © 2014 Elsevier B.V. All rights reserved.

Male circumcision significantly reduces prevalence and load of genital anaerobic bacteria.

Science.gov (United States)

Liu, Cindy M; Hungate, Bruce A; Tobian, Aaron A R; Serwadda, David; Ravel, Jacques; Lester, Richard; Kigozi, Godfrey; Aziz, Maliha; Galiwango, Ronald M; Nalugoda, Fred; Contente-Cuomo, Tania L; Wawer, Maria J; Keim, Paul; Gray, Ronald H; Price, Lance B

2013-04-16

Male circumcision reduces female-to-male HIV transmission. Hypothesized mechanisms for this protective effect include decreased HIV target cell recruitment and activation due to changes in the penis microbiome. We compared the coronal sulcus microbiota of men from a group of uncircumcised controls (n = 77) and from a circumcised intervention group (n = 79) at enrollment and year 1 follow-up in a randomized circumcision trial in Rakai, Uganda. We characterized microbiota using16S rRNA gene-based quantitative PCR (qPCR) and pyrosequencing, log response ratio (LRR), Bayesian classification, nonmetric multidimensional scaling (nMDS), and permutational multivariate analysis of variance (PerMANOVA). At baseline, men in both study arms had comparable coronal sulcus microbiota; however, by year 1, circumcision decreased the total bacterial load and reduced microbiota biodiversity. Specifically, the prevalence and absolute abundance of 12 anaerobic bacterial taxa decreased significantly in the circumcised men. While aerobic bacterial taxa also increased postcircumcision, these gains were minor. The reduction in anaerobes may partly account for the effects of circumcision on reduced HIV acquisition. The bacterial changes identified in this study may play an important role in the HIV risk reduction conferred by male circumcision. Decreasing the load of specific anaerobes could reduce HIV target cell recruitment to the foreskin. Understanding the mechanisms that underlie the benefits of male circumcision could help to identify new intervention strategies for decreasing HIV transmission, applicable to populations with high HIV prevalence where male circumcision is culturally less acceptable.

Quilting after mastectomy significantly reduces seroma formation

African Journals Online (AJOL)

reduce or prevent seroma formation among mastectomy patients ... of this prospective study is to evaluate the effect of surgical quilting ... Seroma was more common in smokers (p=0.003) and was not decreased by the .... explain its aetiology.

Promotion of osteogenic differentiation of stem cells and increase of bone-bonding ability in vivo using urease-treated titanium coated with calcium phosphate and gelatin

International Nuclear Information System (INIS)

Huang, Zhong-Ming; Qi, Yi-Ying; Du, Shao-Hua; Feng, Gang; Yan, Wei-Qi; Unuma, Hidero

2013-01-01

Because of its excellent biocompatibility and low allergenicity, titanium has been widely used for bone replacement and tissue engineering. To produce a desirable composite with enhanced bone response and mechanical strength, in this study bioactive calcium phosphate (CaP) and gelatin composites were coated onto titanium (Ti) via a novel urease technique. The cellular responses to the CaP/gelatin/Ti (CaP/gel/Ti) and bone bonding ability were evaluated with proliferation and osteogenic differentiation of mesenchymal stem cells (MSCs) on CaP/gel/Ti and CaP/Ti in vitro. The results showed that the optical density values, alkaline phosphatase expression and genes expression of MSCs on CaP/gel/Ti were similar to those on CaP/Ti, yet significantly higher than those on pure Ti (p < 0.05). CaP/gel/Ti and CaP/Ti rods (2 mm in diameter, 10 mm in length) were also implanted into femoral shaft of rabbits and pure Ti rods served as control (n = 10). Histological examination, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) measurements were performed at 4 and 8 weeks after the operation. The histological and SEM observations demonstrated clearly that more new bone formed on the surface of CaP/gel/Ti than in the other two groups at each time point. The CaP/gel/Ti bonded to the surrounding bone directly with no intervening soft tissue layer. An interfacial layer, containing Ti, Ca and P, was found to form at the interface between bone and the implant on all three groups by EDS analysis. However, the content of Ca, P in the surface of CaP/gel/Ti implants was more than in the other two groups at each time point. The CaP/gel/Ti modified by the urease method was not only beneficial for MSCs proliferation and osteogenic differentiation, but also favorable for bone bonding ability on Ti implants in vivo, suggesting that Ti functionalized with CaP and gelatin might have a great potential in clinical joint replacement or dental implants. (paper)

Effect of the urease inhibitor phosphoric acid phenyl ester diamide on the utilization of urea-N in top dressing of spring wheat and oats

Energy Technology Data Exchange (ETDEWEB)

Matzel, W; Mueller, S; Lippold, H; Heber, R [Akademie der Landwirtschaftswissenschaften der DDR, Leipzig-Potsdam. Inst. fuer Duengungsforschung

1979-01-01

In pot experiments with spring wheat and oats the application of the urease inhibitor phosphoric acid phenyl ester diamide (PPDA) in addition to top dressing with /sup 15/N-urea revealed a 10% better utilization of the /sup 15/N-urea by the plant (related to the N amount applied). The loss-reducing effect of PPDA was especially felt when there were favourable conditions for NH/sub 3/ volatilization such as rapid hydrolysis of urea on the wet surface of light soil during shooting of the wheat. PPDA did not have any adverse influence on the course of the nitrogen uptake by the cereals during the time of shooting from the urea applied in top dressing. The utilization of the urea-N by the wheat, being about 5 to 6% lower in comparison to ammonium nitrate, under conditions that do not allow NH/sub 3/ losses, is to be attributed to the increased immobilization of the urea-N in the soil. The processes responsible for the nitrogen losses were concluded 3 to 4 weeks after top dressing to the cereals during the shooting period.

Metabolic activity, urease production, antibiotic resistance and virulence in dual species biofilms of Staphylococcus epidermidis and Staphylococcus aureus

Science.gov (United States)

Vandecandelaere, Ilse; Van Nieuwerburgh, Filip; Deforce, Dieter

2017-01-01

In this paper, the metabolic activity in single and dual species biofilms of Staphylococcus epidermidis and Staphylococcus aureus isolates was investigated. Our results demonstrated that there was less metabolic activity in dual species biofilms compared to S. aureus biofilms. However, this was not observed if S. aureus and S. epidermidis were obtained from the same sample. The largest effect on metabolic activity was observed in biofilms of S. aureus Mu50 and S. epidermidis ET-024. A transcriptomic analysis of these dual species biofilms showed that urease genes and genes encoding proteins involved in metabolism were downregulated in comparison to monospecies biofilms. These results were subsequently confirmed by phenotypic assays. As metabolic activity is related to acid production, the pH in dual species biofilms was slightly higher compared to S. aureus Mu50 biofilms. Our results showed that S. epidermidis ET-024 in dual species biofilms inhibits metabolic activity of S. aureus Mu50, leading to less acid production. As a consequence, less urease activity is required to compensate for low pH. Importantly, this effect was biofilm-specific. Also S. aureus Mu50 genes encoding virulence-associated proteins (Spa, SplF and Dps) were upregulated in dual species biofilms compared to monospecies biofilms and using Caenorhabditis elegans infection assays, we demonstrated that more nematodes survived when co-infected with S. epidermidis ET-024 and S. aureus mutants lacking functional spa, splF or dps genes, compared to nematodes infected with S. epidermidis ET-024 and wild- type S. aureus. Finally, S. epidermidis ET-024 genes encoding resistance to oxacillin, erythromycin and tobramycin were upregulated in dual species biofilms and increased resistance was subsequently confirmed. Our data indicate that both species in dual species biofilms of S. epidermidis and S. aureus influence each other’s behavior, but additional studies are required necessary to elucidate the exact

Effect of enzyme location on activity and stability of trypsin and urease immobilized on porous membranes by using layer-by-layer self-assembly of polyelectrolyte

OpenAIRE

Guedidi, Sadika; Yürekli, Yılmaz; Deratani, André; Déjardin, Philippe; Innocent, Christophe; Altınkaya, Sacide; Roudesli, Sadok; Yemenicioğlu, Ahmet

2010-01-01

The layer-by-layer (LbL) self-assembly of polyelectrolyte is one of the simplest ways to immobilize enzyme on membrane. In this paper, the immobilization of trypsin (TRY) and urease (URE) on polyacrylonitrile based membranes using the LbL assembly technique was presented. The studied systems consisted in bilayered assemblies with the enzyme layer as the outer layer and trilayered assemblies with the enzyme layer as the inner sandwiched layer. The membrane pore size was chosen so that the smal...

Defibrillator charging before rhythm analysis significantly reduces hands-off time during resuscitation

DEFF Research Database (Denmark)

Hansen, L. K.; Folkestad, L.; Brabrand, M.

2013-01-01

BACKGROUND: Our objective was to reduce hands-off time during cardiopulmonary resuscitation as increased hands-off time leads to higher mortality. METHODS: The European Resuscitation Council (ERC) 2005 and ERC 2010 guidelines were compared with an alternative sequence (ALT). Pulseless ventricular...... physicians were included. All had prior experience in advanced life support. Chest compressions were shorter interrupted using ALT (mean, 6.7 vs 13.0 seconds). Analyzing data for ventricular tachycardia scenarios only, hands-off time was shorter using ALT (mean, 7.1 vs 18.2 seconds). In ERC 2010 vs ALT, 12...... physicians were included. Two physicians had not prior experience in advanced life support. Hands-off time was reduced using ALT (mean, 3.9 vs 5.6 seconds). Looking solely at ventricular tachycardia scenarios, hands-off time was shortened using ALT (mean, 4.5 vs 7.6 seconds). No significant reduction...

Finding of No Significant Impact: Expand RV Storage Lot United States Air Force Academy, CO

Science.gov (United States)

2006-09-18

the surface layer is grayish brown gravelly sandy loam about 14 inches thick. The underlying material is light yellowish brown gravelly loamy sand...inhibit the urease activity of soil microbes by up to 47% and 35%, respectively, suggesting that sources of nitrogen other than urea should be used

Detection of clarithromycin-resistant Helicobacter pylori by polymerase chain reaction using residual samples from rapid urease test

Directory of Open Access Journals (Sweden)

Jae-Sik Jeon

2017-01-01

Full Text Available Background: Approximately 50% of the world population is infected with Helicobacter pylori, which corresponds to a high infection rate. Furthermore, the incidence of antibiotic-resistant H. pylori has increased with the recent rise in use of antibiotics for H. pylori elimination, suggesting growing treatment failures. Aim: The study was aimed to assess the use of residual samples from rapid urease test (RUT for biomolecular testing as an effective and accurate method to detect antibiotic-resistant H. pylori. Settings and Design: This study was a retrospective study performed using data obtained from medical records of previously isolated H. pylori strains. Materials and Methods: RUT was conducted for 5440 biopsy samples from individuals who underwent health examination in South Korea. Subsequently, 469 RUT residual samples were randomly selected and subjected to polymerase chain reaction (PCR to detect antibiotic-resistant H. pylori. Statistical Analysis Used: The Chi-square test was used to analyse categorical data. P < 0.05 was considered statistically significant. Results: The results showed a concordance between the results of PCR and conventional RUT in 450 of 469 samples, suggesting that the H. pylori PCR test is a time- and cost-effective detection method. Conclusions: This study demonstrated that PCR test can aid physicians to prescribe the appropriate antibiotics at the time of diagnosis, thus preventing the reduction in H. pylori eradication due to antibiotic resistance, averting progression to serious diseases and increasing the treatment success rate.

Proteus mirabilis fimbriae- and urease-dependent clusters assemble in an extracellular niche to initiate bladder stone formation.

Science.gov (United States)

Schaffer, Jessica N; Norsworthy, Allison N; Sun, Tung-Tien; Pearson, Melanie M

2016-04-19

The catheter-associated uropathogenProteus mirabilisfrequently causes urinary stones, but little has been known about the initial stages of bladder colonization and stone formation. We found thatP. mirabilisrapidly invades the bladder urothelium, but generally fails to establish an intracellular niche. Instead, it forms extracellular clusters in the bladder lumen, which form foci of mineral deposition consistent with development of urinary stones. These clusters elicit a robust neutrophil response, and we present evidence of neutrophil extracellular trap generation during experimental urinary tract infection. We identified two virulence factors required for cluster development: urease, which is required for urolithiasis, and mannose-resistantProteus-like fimbriae. The extracellular cluster formation byP. mirabilisstands in direct contrast to uropathogenicEscherichia coli, which readily formed intracellular bacterial communities but not luminal clusters or urinary stones. We propose that extracellular clusters are a key mechanism ofP. mirabilissurvival and virulence in the bladder.

Iridium oxide pH sensor for biomedical applications. Case urea-urease in real urine samples.

Science.gov (United States)

Prats-Alfonso, Elisabet; Abad, Llibertat; Casañ-Pastor, Nieves; Gonzalo-Ruiz, Javier; Baldrich, Eva

2013-01-15

This work demonstrates the implementation of iridium oxide films (IROF) grown on silicon-based thin-film platinum microelectrodes, their utilization as a pH sensor, and their successful formatting into a urea pH sensor. In this context, Pt electrodes were fabricated on Silicon by using standard photolithography and lift-off procedures and IROF thin films were growth by a dynamic oxidation electrodeposition method (AEIROF). The AEIROF pH sensor reported showed a super-Nerstian (72.9±0.9mV/pH) response between pH 3 and 11, with residual standard deviation of both repeatability and reproducibility below 5%, and resolution of 0.03 pH units. For their application as urea pH sensors, AEIROF electrodes were reversibly modified with urease-coated magnetic microparticles (MP) using a magnet. The urea pH sensor provided fast detection of urea between 78μM and 20mM in saline solution, in sample volumes of just 50μL. The applicability to urea determination in real urine samples is discussed. Copyright © 2012 Elsevier B.V. All rights reserved.

Sodium-Reduced Meat and Poultry Products Contain a Significant Amount of Potassium from Food Additives.

Science.gov (United States)

Parpia, Arti Sharma; Goldstein, Marc B; Arcand, JoAnne; Cho, France; L'Abbé, Mary R; Darling, Pauline B

2018-05-01

counterparts (mean difference [95% CI]: 486 [334-638]; Padditives appearing on the product label ingredient list, did not significantly differ between the two groups. Potassium additives are frequently added to sodium-reduced MPPs in amounts that significantly contribute to the potassium load for patients with impaired renal handling of potassium caused by chronic kidney disease and certain medications. Patients requiring potassium restriction should be counseled to be cautious regarding the potassium content of sodium-reduced MPPs and encouraged to make food choices accordingly. Copyright © 2018 Academy of Nutrition and Dietetics. Published by Elsevier Inc. All rights reserved.

[Dynamics of aquic brown soil enzyme activities under no-tillage].

Science.gov (United States)

Liu, Xiumei; Li, Qi; Liang, Wenju; Jiang, Yong; Wen, Dazhong

2006-12-01

This paper studied the effects of no-tillage on the dynamics of invertase, urease and acid phosphatase activities in an aquic brown soil during maize growing season. The results showed that in 0 - 10 cm soil layer, the invertase activity at jointing, trumpet-shaped and ripening stages, urease activity at jointing and booting stages, and acid phosphatase activity at booting and ripening stages were significantly higher under no-tillage (NT) than under conventional tillage (CT). In 10 - 20 cm soil layer, the invertase activity at seedling, jointing and trumpet-shaped stages was significantly different between NT and CT, and the urease activity during whole growing season except at booting stage was significantly higher under NT than under CT. In 20 - 30 cm soil layer, the invertase activity during maize growing season was significantly lower under NT than under CT, and urease activity at seedling stage and acid phosphate activity at ripening stage were significantly different between these two treatments. Under NT, there was a decreasing trend of soil enzyme activities with increasing soil depth; while under CT, soil invertase and acid phosphatase activities increased, but urease activity decreased with increasing soil depth.

A chimpanzee recognizes synthetic speech with significantly reduced acoustic cues to phonetic content.

Science.gov (United States)

Heimbauer, Lisa A; Beran, Michael J; Owren, Michael J

2011-07-26

A long-standing debate concerns whether humans are specialized for speech perception, which some researchers argue is demonstrated by the ability to understand synthetic speech with significantly reduced acoustic cues to phonetic content. We tested a chimpanzee (Pan troglodytes) that recognizes 128 spoken words, asking whether she could understand such speech. Three experiments presented 48 individual words, with the animal selecting a corresponding visuographic symbol from among four alternatives. Experiment 1 tested spectrally reduced, noise-vocoded (NV) synthesis, originally developed to simulate input received by human cochlear-implant users. Experiment 2 tested "impossibly unspeechlike" sine-wave (SW) synthesis, which reduces speech to just three moving tones. Although receiving only intermittent and noncontingent reward, the chimpanzee performed well above chance level, including when hearing synthetic versions for the first time. Recognition of SW words was least accurate but improved in experiment 3 when natural words in the same session were rewarded. The chimpanzee was more accurate with NV than SW versions, as were 32 human participants hearing these items. The chimpanzee's ability to spontaneously recognize acoustically reduced synthetic words suggests that experience rather than specialization is critical for speech-perception capabilities that some have suggested are uniquely human. Copyright © 2011 Elsevier Ltd. All rights reserved.

Intensity-modulated radiotherapy significantly reduces xerostomia compared with conventional radiotherapy

International Nuclear Information System (INIS)

Braam, Petra M.; Terhaard, Chris H.J. M.D.; Roesink, Judith M.; Raaijmakers, Cornelis P.J.

2006-01-01

Purpose: Xerostomia is a severe complication after radiotherapy for oropharyngeal cancer, as the salivary glands are in close proximity with the primary tumor. Intensity-modulated radiotherapy (IMRT) offers theoretical advantages for normal tissue sparing. A Phase II study was conducted to determine the value of IMRT for salivary output preservation compared with conventional radiotherapy (CRT). Methods and Materials: A total of 56 patients with oropharyngeal cancer were prospectively evaluated. Of these, 30 patients were treated with IMRT and 26 with CRT. Stimulated parotid salivary flow was measured before, 6 weeks, and 6 months after treatment. A complication was defined as a stimulated parotid flow rate <25% of the preradiotherapy flow rate. Results: The mean dose to the parotid glands was 48.1 Gy (SD 14 Gy) for CRT and 33.7 Gy (SD 10 Gy) for IMRT (p < 0.005). The mean parotid flow ratio 6 weeks and 6 months after treatment was respectively 41% and 64% for IMRT and respectively 11% and 18% for CRT. As a result, 6 weeks after treatment, the number of parotid flow complications was significantly lower after IMRT (55%) than after CRT (87%) (p = 0.002). The number of complications 6 months after treatment was 56% for IMRT and 81% for CRT (p = 0.04). Conclusions: IMRT significantly reduces the number of parotid flow complications for patients with oropharyngeal cancer

Harnessing the bio-mineralization ability of urease producing Serratia marcescens and Enterobacter cloacae EMB19 for remediation of heavy metal cadmium (II).

Science.gov (United States)

Bhattacharya, Amrik; Naik, S N; Khare, S K

2018-06-01

In the present study, urease positive Serratia marcescens (NCIM2919) and Enterobacter cloacae EMB19 (MTCC10649) were individually evaluated for remediation of cadmium (II) using ureolysis-induced calcium carbonate precipitation. Both the cultures were observed to efficiently remove cadmium from the media through co-precipitation of Cd (II) and Ca (II). S. marcescens and E. cloacae EMB19, respectively showed 96 and 98% removal of initial 5.0 mg L -1 soluble Cd (II) from the urea and CaCl 2 laden media at 96 h of incubation period. At higher Cd (II) concentrations of 10 and 15 mg L -1 , cadmium removal efficiency was much higher in case of E. cloacae EMB19 compared to S. marcescens. In-vitro cadmium (II) remediation study using urease containing cell-free culture supernatant of S. marcescens and E. cloacae EMB19 showed respective 98 and 53% removal of initial 50 mg L -1  Cd (II) from the reaction mixtures in co-presence of Ca (II). While in sole presence of Cd (II), only 16 and 8% removal of Cd (II) were detected for S. marcescens and E. cloacae EMB19, respectively. The elemental analysis of the co-precipitated mineral products using Energy Dispersive X-ray spectroscopy (EDX) clearly showed the prevalence of Ca and Cd ions. The morphology Cd-Ca composites formed with respect to both the cultures were observed to be of different shape and size as revealed through Scanning Electron Microscopy (SEM). Entire study hence comes out with a sustainable bioremediation option which could be effectively used to tackle Cd (II) or other heavy metal pollution. Copyright © 2018 Elsevier Ltd. All rights reserved.

Molecular identification and characterisation of catalase and catalase-like protein genes in urease-positive thermophilic Campylobacter (UPTC).

Science.gov (United States)

Nakajima, T; Kuribayashi, T; Moore, J E; Millar, B C; Yamamoto, S; Matsuda, Motoo

2016-01-01

Thermophilic Campylobacter are important bacterial pathogens of foodborne diseases worldwide. These organisms' physiology requires a microaerophilic atmosphere. To date, little is known about the protective catalase mechanism in urease-positive thermophilic campylobacters (UPTC); hence, it was the aim of this study to identify and characterise catalase and catalase-like protein genes in these organisms. Catalase (katA) and catalase (Kat)-like protein genes from the Japanese UPTC CF89-12 strain were molecularly analysed and compared with C. lari RM2100 and other C. lari and thermophilic Campylobacter reference isolates. A possible open reading frame of 1,422 base pairs, predicted to encode a peptide of 474 amino acid residues, with calculated molecular weight of 52.7 kilo Daltons for katA, was identified within UPTC CF89-12. A probable ribosome binding site, two putative promoters and a putative ρ-independent transcription terminator were also identified within katA. A similar katA cluster also existed in the C. lari RM2100 strain, except that this strain carries no DcuB genes. However, the Kat-like protein gene or any other homologue(s) were never identified in the C. lari RM2100 strain, or in C. jejuni and C. upsaliensis. This study demonstrates the presence of catalase/catalase-like protein genes in UPTC organisms. These findings are significant in that they suggest that UPTC organisms have the protective genetic capability of helping protect the organisms from toxic oxygen stress, which may help them to survive in physiologically harsh environments, both within human and animal hosts, as well as in the natural environment.

Short term physiological implications of NBPT application on the N metabolism of Pisum sativum and Spinacea oleracea.

Science.gov (United States)

Cruchaga, Saioa; Artola, Ekhiñe; Lasa, Berta; Ariz, Idoia; Irigoyen, Ignacio; Moran, Jose Fernando; Aparicio-Tejo, Pedro M

2011-03-01

The application of urease inhibitors in conjunction with urea fertilizers as a means of reducing N loss due to ammonia volatilization requires an in-depth study of the physiological effects of these inhibitors on plants. The aim of this study was to determine how the urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT) affects N metabolism in pea and spinach. Plants were cultivated in pure hydroponic culture with urea as the sole N source. After 2 weeks of growth for pea, and 3 weeks for spinach, half of the plants received NBPT in their nutrient solution. Urease activity, urea and ammonium content, free amino acid composition and soluble protein were determined in leaves and roots at days 0, 1, 2, 4, 7 and 9, and the NBPT content in these tissues was determined 48h after inhibitor application. The results suggest that the effects of NBPT on spinach and pea urease activity differ, with pea being most affected by this treatment, and that the NBPT absorbed by the plant caused a clear inhibition of the urease activity in pea leaf and roots. The high urea concentration observed in leaves was associated with the development of necrotic leaf margins, and was further evidence of NBPT inhibition in these plants. A decrease in the ammonium content in roots, where N assimilation mainly takes place, was also observed. Consequently, total amino acid contents were drastically reduced upon NBPT treatment, indicating a strong alteration of the N metabolism. Furthermore, the amino acid profile showed that amidic amino acids were major components of the reduced pool of amino acids. In contrast, NBPT was absorbed to a much lesser degree by spinach plants than pea plants (35% less) and did not produce a clear inhibition of urease activity in this species. Copyright © 2010 Elsevier GmbH. All rights reserved.

Ammonia volatilization of urea in the out-of-season corn Volatilização de amônia da ureia na cultura do milho safrinha

Directory of Open Access Journals (Sweden)

Hamilton Seron Pereira

2009-12-01

Full Text Available The aim of this study was to evaluate the N losses due to volatilization at different rates of common urea, polymer coated urea and urease inhibitor-treated urea in the out-of-season corn, using semi-open static collectors. The treatments consisted of N levels on side-dressing fertilization with urea in different treatments: (a control (without N, (b urea 40 kg ha-1 N, (c urea 80 kg ha-1 N, (d polymer coated urea 40 kg ha-1 N, (e polymer coated urea 80 kg ha-1 N and (f urea with the urease inhibitor (UI N 80 kg ha-1 N. The results showed that the treatments with polymer coated urea and with urease inhibitor-treated urea reduced the volatilization of N around 50 % compared to common urea, either in the first and the second N side-dressing fertilizations. Thus, they demonstrate that the polymer coat and the urease inhibitors were effective in reducing the volatilization of urea N applied in coverage, which resulted in higher productivity. There was also increasing urease activity in the treatments with application of common urea.O objetivo deste estudo foi avaliar as perdas por volatilização doN em diferentes doses de ureia comum, revestida com polímeros e tratada com inibidores de urease na cultura do milho safrinha, utilizando coletores semiabertos estáticos. O N, na forma de ureia, foi aplicado em cobertura nas seguintes doses: milho safrinha solteiro (sem N; ureia - 40 kg ha-1 de N; ureia - 80 kg ha-1 de N; ureia revestida com polímeros - 40 kg ha-1 de N; ureia revestida com polímeros 80 kg ha-1 de N; e ureia com inibidor de urease (UI - 80 kg ha-1 de N. Os resultados mostraram que os tratamentos com ureia revestida e ureia com inibidor de urease reduziram a volatilização de N em torno de 50 % em relação à ureia comum, tanto na primeira quanto na segunda cobertura nitrogenada. Foi demonstrado que o revestimento da ureia e o inibidor da urease foram eficientes na redução da volatilização do N da ureia aplicados em cobertura, o

Nano-CL-20/HMX Cocrystal Explosive for Significantly Reduced Mechanical Sensitivity

Directory of Open Access Journals (Sweden)

Chongwei An

2017-01-01

Full Text Available Spray drying method was used to prepare cocrystals of hexanitrohexaazaisowurtzitane (CL-20 and cyclotetramethylene tetranitramine (HMX. Raw materials and cocrystals were characterized using scanning electron microscopy, X-ray diffraction, differential scanning calorimetry, Raman spectroscopy, and Fourier transform infrared spectroscopy. Impact and friction sensitivity of cocrystals were tested and analyzed. Results show that, after preparation by spray drying method, microparticles were spherical in shape and 0.5–5 µm in size. Particles formed aggregates of numerous tiny plate-like cocrystals, whereas CL-20/HMX cocrystals had thicknesses of below 100 nm. Cocrystals were formed by C–H⋯O bonding between –NO2 (CL-20 and –CH2– (HMX. Nanococrystal explosives exhibited drop height of 47.3 cm, and friction demonstrated explosion probability of 64%. Compared with raw HMX, cocrystals displayed significantly reduced mechanical sensitivity.

Unprecedented loss of ammonia assimilation capability in a urease-encoding bacterial mutualist

Directory of Open Access Journals (Sweden)

Wernegreen Jennifer J

2010-12-01

Full Text Available Abstract Background Blochmannia are obligately intracellular bacterial mutualists of ants of the tribe Camponotini. Blochmannia perform key nutritional functions for the host, including synthesis of several essential amino acids. We used Illumina technology to sequence the genome of Blochmannia associated with Camponotus vafer. Results Although Blochmannia vafer retains many nutritional functions, it is missing glutamine synthetase (glnA, a component of the nitrogen recycling pathway encoded by the previously sequenced B. floridanus and B. pennsylvanicus. With the exception of Ureaplasma, B. vafer is the only sequenced bacterium to date that encodes urease but lacks the ability to assimilate ammonia into glutamine or glutamate. Loss of glnA occurred in a deletion hotspot near the putative replication origin. Overall, compared to the likely gene set of their common ancestor, 31 genes are missing or eroded in B. vafer, compared to 28 in B. floridanus and four in B. pennsylvanicus. Three genes (queA, visC and yggS show convergent loss or erosion, suggesting relaxed selection for their functions. Eight B. vafer genes contain frameshifts in homopolymeric tracts that may be corrected by transcriptional slippage. Two of these encode DNA replication proteins: dnaX, which we infer is also frameshifted in B. floridanus, and dnaG. Conclusions Comparing the B. vafer genome with B. pennsylvanicus and B. floridanus refines the core genes shared within the mutualist group, thereby clarifying functions required across ant host species. This third genome also allows us to track gene loss and erosion in a phylogenetic context to more fully understand processes of genome reduction.

Rapid urease test and endoscopic data in dynamic in case of peptic ulcers in former Chernobyl accident clean-up workers

International Nuclear Information System (INIS)

Orlikovs, G.; Seleznovs, J.; Farbtuha, T.; Straupeniece, I.; Kuzenko, A.; Pokrotnieks, J.

2002-01-01

111 peptic ulcer patients former Chernobyl accident clean-up workers were examined. The patients have been working in the damaged zone during 1986-87 years receiving small radiation dosages. Chronic peptic gastric and duodenal ulcers appeared in them later. The goal of the trial is to investigate the effectiveness of Helicobacter pylori eradication measures in triple-therapy course of medium duration (10 days) include ranitidine, amoxycillinum, and methronidazolum. Upper gastrointestinal endoscopy was accompanied by rapid urease test. The test was repeated after a 1-year period. Analysing the data results we ascertain that the prolonged success of triple-therapy is rather ineffective and have unclear correlation with endoscopic data. This is much evident in case of gastric ulcers. These results testify that clinical course of peptic ulcers in case of post-radiation syndrome differs from the same in population. (authors)

Genome analysis of urease positive Serratia marcescens, co-producing SRT-2 and AAC(6')-Ic with multidrug efflux pumps for antimicrobial resistance.

Science.gov (United States)

Srinivasan, Vijaya Bharathi; Rajamohan, Govindan

2018-04-05

In this study, we present the genome sequence of Serratia marcescens SM03, recovered from a human gut in India. The final assembly consists of 26 scaffolds (4620 coding DNA sequences, 5.08 Mb, 59.6% G + C ratio) and 79 tRNA genes. Analysis identified novel genes associated with lactose utilization, virulence, P-loop GTPases involved in urease production, CFA/I fimbriae apparatus and Yersinia - type CRISPR proteins. Antibiotic susceptibility testing indicated drug tolerant phenotype and inhibition assays demonstrated involvement of extrusion in resistance. Presence of enzymes SRT-2, AAC(6')-Ic, with additional Ybh transporter and EamA-like efflux pumps signifies the genetic plasticity observed in S. marcescens SM03. Copyright © 2018 Elsevier Inc. All rights reserved.

Utilization of quercetin and quercetin glycosides from onion (Allium cepa L.) solid waste as an antioxidant, urease and xanthine oxidase inhibitors.

Science.gov (United States)

Nile, Shivraj Hariram; Nile, Arti Shivraj; Keum, Young Soo; Sharma, Kavita

2017-11-15

This study aimed to determine the flavonol glycosides from onion solid waste (OSW) using HPLC analysis, with antioxidant and enzyme inhibitory activities. We found considerable amount of quercetin-4'-O-monoglucoside (QMG: 254.85), quercetin-3,4'-O-diglucoside (QDG: 162.34), quercetin (Q: 60.44), and isorhamnetin-3-glucoside (IMG: 23.92) (mg/100g) dry weight (DW) of OSW. For OSW, the methanol and ethanol showed the strongest antioxidant activities, followed by ethyl acetate, chloroform, and n-hexane extracts. Among the flavonols, Q and QDG possessed higher antioxidant activities. OSW and flavonol glycosides displayed significant enzyme inhibitory activity, with IC 50 values ranging from 12.5±0.11 to 32.5±0.28 for OSW, 8.2±0.07 to 16.8±0.02 for flavonol glycosides, and 4.2±0.05μg/mL for thiourea (positive control) towards urease; while 15.2±0.8 to 35.8±0.2 (μg/mL) for OSW, 10.5±0.06 to 20.8±0.05 (μg/mL) for flavonol glycosides, and 6.5±0.05μg/mL for allopurinol (positive control) towards xanthine oxidase, respectively. The OSW and flavonol glycosides may thus be considered as potential antioxidant and antigout agents. Copyright © 2017 Elsevier Ltd. All rights reserved.

Biochemical Effects of Cadmium Exposure and the Potential Pharmacologic Significance of Cadmium Mediated Hydrolase Inhibition

Science.gov (United States)

1997-04-18

DNA polymerase Alcohol dehydrogenase Hexokinase Glucose-6- phosphatase Arginase Pyruvate kinase (also requires Mg2•) Urease Nitrate...cyclohexane. The layers are separated by centrifugation (5 min at 1000 x g), the top organic layer is removed and dried with anhydrous sodium sulfate...An aliquot of the dried organic layer is transferred to a clean tube and evaporated under a gentle stream of nitrogen at room temperature

The significance of sensory appeal for reduced meat consumption.

Science.gov (United States)

Tucker, Corrina A

2014-10-01

Reducing meat (over-)consumption as a way to help address environmental deterioration will require a range of strategies, and any such strategies will benefit from understanding how individuals might respond to various meat consumption practices. To investigate how New Zealanders perceive such a range of practices, in this instance in vitro meat, eating nose-to-tail, entomophagy and reducing meat consumption, focus groups involving a total of 69 participants were held around the country. While it is the damaging environmental implications of intensive farming practices and the projected continuation of increasing global consumer demand for meat products that has propelled this research, when asked to consider variations on the conventional meat-centric diet common to many New Zealanders, it was the sensory appeal of the areas considered that was deemed most problematic. While an ecological rationale for considering these 'meat' alternatives was recognised and considered important by most, transforming this value into action looks far less promising given the recurrent sensory objections to consuming different protein-based foods or of reducing meat consumption. This article considers the responses of focus group participants in relation to each of the dietary practices outlined, and offers suggestions on ways to encourage a more environmentally viable diet. Copyright © 2014 Elsevier Ltd. All rights reserved.

Application of Serratia marcescens RZ-21 significantly enhances peanut yield and remediates continuously cropped peanut soil.

Science.gov (United States)

Ma, Hai-Yan; Yang, Bo; Wang, Hong-Wei; Yang, Qi-Yin; Dai, Chuan-Chao

2016-01-15

Continuous cropping practices cause a severe decline in peanut yield. The aim of this study was to investigate the remediation effect of Serratia marcescens on continuously cropped peanut soil. A pot experiment was conducted under natural conditions to determine peanut agronomic indices, soil microorganism characteristics, soil enzyme activities and antagonism ability to typical pathogens at different growth stages. Four treatments were applied to red soil as follows: an active fermentation liquor of S. marcescens (RZ-21), an equivalent sterilized fermentation liquor (M), an equivalent fermentation medium (P) and distilled water (CK). S. marcescens significantly inhibited the two typical plant pathogens Fusarium oxysporum A1 and Ralstonia solanacearum B1 and reduced their populations in rhizosphere soil. The RZ-21 treatment significantly increased peanut yield, vine dry weight, root nodules and taproot length by 62.3, 33, 72 and 61.4% respectively, followed by the M treatment. The P treatment also increased root nodules and root length slightly. RZ-21 also enhanced the activities of soil urease, sucrase and hydrogen peroxidase at various stages. In addition, RZ-21 and M treatments increased the average population of soil bacteria and decreased the average population of fungi in the three critical peanut growth stages, except for M in the case of the fungal population at flowering, thus balancing the structure of the soil microorganism community. This is the first report of S. marcescens being applied to continuously cropped peanut soil. The results suggest that S. marcescens RZ-21 has the potential to improve the soil environment and agricultural products and thus allow the development of sustainable management practices. © 2015 Society of Chemical Industry.

A pilot weight reduction program over one year significantly reduced DNA strand breaks in obese subjects

Directory of Open Access Journals (Sweden)

Karl-Heinz Wagner

2015-05-01

Conclusion: A sustainable lifestyle change under supervision including physical activity and diet quality over a period of one year was not only responsible to reduce body weight and BMI but also led to significant reduction in all parameters of the comet assay. These results underline the importance of body weight reduction and highlight the positive changes in DNA stability.

Cytochemical and biological properties of Mycobacterium bovis BCG.

Science.gov (United States)

Slosárek, M

1977-01-01

It was the aim of the present communication to find a simple test for a reliable discrimination of Mycobacterium bovis BCG from Mycobacterium tuberculosis. A total of 26 BCG strains, out of them 10 Czechoslovak strains (2 lyophilized cultures of BCG of different batch, 6 strains isolated from abscesses of children after BCG-vaccination and 2 strains from fatal cases after BCG-vaccination) and 16 strains obtained from foreign laboratories, were used. Of the tested characteristics a combination of 3 tests, sensitivity to 1 microgram of 2-thiophene carbonylhydrazide (TCH), activity of 3 acylamidases (urease, nicotinamidase and pyrazinamidase) and a quantitative nitrate test, was found to be most advantageous. The Czechoslovak strains of Mycobacterium bovis BCG were fully sensitive to TCH, of the 3 acylamidases mentioned above only urease was positive and nitrate was reduced only little or not at all. On the other hand, strains of Mycobacterium tuberculosis were always resistant to TCH, had positive urease, nicotinamidase and pyrazinamidase and reduced nitrate very intensively.

Helicobacter pylori moves through mucus by reducing mucin viscoelasticity

OpenAIRE

Celli, Jonathan P.; Turner, Bradley S.; Afdhal, Nezam H.; Keates, Sarah; Ghiran, Ionita; Kelly, Ciaran P.; Ewoldt, Randy H.; McKinley, Gareth H.; So, Peter; Erramilli, Shyamsunder; Bansil, Rama

2009-01-01

The ulcer-causing gastric pathogen Helicobacter pylori is the only bacterium known to colonize the harsh acidic environment of the human stomach. H. pylori survives in acidic conditions by producing urease, which catalyzes hydrolysis of urea to yield ammonia thus elevating the pH of its environment. However, the manner in which H. pylori is able to swim through the viscoelastic mucus gel that coats the stomach wall remains poorly understood. Previous rheology studies on gastric mucin, the key...

Prospective study to evaluate the number and the location of biopsies in rapid urease test for diagnosis of Helicobacter Pylori

Directory of Open Access Journals (Sweden)

Antoine Abou Rached

2017-11-01

Full Text Available Helicobacter pylori (H. pylori can cause a wide variety of illnesses such as peptic ulcer disease, gastric adenocarcinoma and mucosa-associated lymphoid tissue (MALT lymphoma. The diagnosis and eradication of H. pylori are crucial. The diagnosis of H. pylori is usually based on the rapid urease test (RUT and gastric antral biopsy for histology. The aim of this study is to evaluate the numbers of needed biopsies and their location (antrum/fundus to obtain optimal result for the diagnosis of H. pylori. Three hundred fifty consecutive patients were recruited, 210 fulfill the inclusion criteria and had nine gastric biopsies for the detection of H. pylori infection: two antral for the first RUT (RUT1, one antral and one fundic for the second (RUT2, one antral for the third (RUT3 and two antral with two fundic for histology (HES, Giemsa, PAS. The reading of the 3 types of RUT was performed at 1 hour, 3 hours and 24 hours and biopsies were read by two experienced pathologists not informed about the result of RUT. Results of RUT were considered positive if H. pylori was found on histology of at least one biopsy. The RUT1 at 1h, 3h and 24h has a sensitivity of 72%, 82% and 89% and a specificity of 100%, 99% and 87% respectively. The positive predictive value (PPV was 100%, 99% and 85% respectively and the negative predictive value (NPV of 81%, 87% and 90%. The RUT2 at 1h, 3h and 24h, respectively, had a sensitivity of 86%, 87% and 91% and a specificity of 99%, 97% and 90%. The PPV was 99%, 96% and 88% and NPV of 89%, 90%, 94%. The RUT3 at 1h, 3h and 24h, respectively, had a sensitivity of 70%, 74% and 84% and a specificity of 99%, 99% and 94%. The PPV was 99%, 99% and 92% and NPV of 79%, 81% and 87%. The best sensitivity and specificity were obtained for RUT1 read at 3h, for RUT2 read 1h and 3h, and the RUT3 read at 24h.This study demonstrates that the best sensitivity and specificity of rapid test for urease is obtained when fundic plus antral biopsy

Synthesis of N-(6-Arylbenzo[d]thiazole-2-acetamide Derivatives and Their Biological Activities: An Experimental and Computational Approach.

Science.gov (United States)

Gull, Yasmeen; Rasool, Nasir; Noreen, Mnaza; Altaf, Ataf Ali; Musharraf, Syed Ghulam; Zubair, Muhammad; Nasim, Faiz-Ul-Hassan; Yaqoob, Asma; DeFeo, Vincenzo; Zia-Ul-Haq, Muhammad

2016-02-25

A new series of N-(6-arylbenzo[d]thiazol-2-yl)acetamides were synthesized by C-C coupling methodology in the presence of Pd(0) using various aryl boronic pinacol ester/acids. The newly synthesized compounds were evaluated for various biological activities like antioxidant, haemolytic, antibacterial and urease inhibition. In bioassays these compounds were found to have moderate to good activities. Among the tested biological activities screened these compounds displayed the most significant activity for urease inhibition. In urease inhibition, all compounds were found more active than the standard used. The compound N-(6-(p-tolyl)benzo[d]thiazol-2-yl)acetamide was found to be the most active. To understand this urease inhibition, molecular docking studies were performed. The in silico studies showed that these acetamide derivatives bind to the non-metallic active site of the urease enzyme. Structure-activity studies revealed that H-bonding of compounds with the enzyme is important for its inhibition.

[Effects of controlled release blend bulk urea on soil nitrogen and soil enzyme activity in wheat and rice fields].

Science.gov (United States)

Zhang, Jing Sheng; Wang, Chang Quan; Li, Bing; Liang, Jing Yue; He, Jie; Xiang, Hao; Yin, Bin; Luo, Jing

2017-06-18

A field experiment was conducted to investigate the effect of controlled-release fertilizer (CRF) combined with urea (UR) on the soil fertility and environment in wheat-rice rotation system. Changes in four forms of nitrogen (total nitrogen, ammonium nitrogen, nitrate nitrogen, and microbial biomass nitrogen) and in activities of three soil enzymes participating in nitrogen transformation (urease, protease, and nitrate reductase) were measured in seven fertilization treatments (no fertilization, routine fertilization, 10%CRF+90%UR, 20%CRF+80%UR, 40%CRF+60%UR, 80%CRF+20%UR, and 100%CRF). The results showed that soil total nitrogen was stable in the whole growth period of wheat and rice. There was no significant difference among the treatments of over 20% CRF in soil total nitrogen content of wheat and rice. The soil inorganic nitrogen content was increased dramatically in treatments of 40% or above CRF during the mid-late growing stages of wheat and rice. With the advance of the growth period, conventional fertilization significantly decreased soil microbial biomass nitrogen, but the treatments of 40% and above CRF increased the soil microbial biomass nitrogen significantly. The soil enzyme activities were increased with over 40% of CRF in the mid-late growing stage of wheat and rice. By increasing the CRF ratio, the soil protease activity and nitrate reductase activity were improved gradually, and peaked in 100% CRF. The treatments of above 20% CRF could decrease the urease activity in tillering stage of rice and delay the peak of ammonium nitrogen, which would benefit nitrogen loss reduction. The treatments of 40% and above CRF were beneficial to improving soil nitrogen supply and enhancing soil urease and protease activities, which could promote the effectiveness of nitrogen during the later growth stages of wheat and rice. The 100% CRF treatment improved the nitrate reductase activity significantly during the later stage of wheat and rice. Compared with the

GenBank blastx search result: AK104368 [KOME

Lifescience Database Archive (English)

Full Text Available AK104368 001-035-E04 U35248.2 Streptococcus salivarius urea transporter (ureI) gene, partial cds; urease... beta subunit (ureA), urease gamma subunit (ureB), urease alpha subunit (ureC), urease ...accessory protein (ureE), urease accessory protein (ureF), urease accessory protein (ureG), urease accessory

Reduced bone mineral density is not associated with significantly reduced bone quality in men and women practicing long-term calorie restriction with adequate nutrition.

Science.gov (United States)

Villareal, Dennis T; Kotyk, John J; Armamento-Villareal, Reina C; Kenguva, Venkata; Seaman, Pamela; Shahar, Allon; Wald, Michael J; Kleerekoper, Michael; Fontana, Luigi

2011-02-01

Calorie restriction (CR) reduces bone quantity but not bone quality in rodents. Nothing is known regarding the long-term effects of CR with adequate intake of vitamin and minerals on bone quantity and quality in middle-aged lean individuals. In this study, we evaluated body composition, bone mineral density (BMD), and serum markers of bone turnover and inflammation in 32 volunteers who had been eating a CR diet (approximately 35% less calories than controls) for an average of 6.8 ± 5.2 years (mean age 52.7 ± 10.3 years) and 32 age- and sex-matched sedentary controls eating Western diets (WD). In a subgroup of 10 CR and 10 WD volunteers, we also measured trabecular bone (TB) microarchitecture of the distal radius using high-resolution magnetic resonance imaging. We found that the CR volunteers had significantly lower body mass index than the WD volunteers (18.9 ± 1.2 vs. 26.5 ± 2.2 kg m(-2) ; P = 0.0001). BMD of the lumbar spine (0.870 ± 0.11 vs. 1.138 ± 0.12 g cm(-2) , P = 0.0001) and hip (0.806 ± 0.12 vs. 1.047 ± 0.12 g cm(-2) , P = 0.0001) was also lower in the CR than in the WD group. Serum C-terminal telopeptide and bone-specific alkaline phosphatase concentration were similar between groups, while serum C-reactive protein (0.19 ± 0.26 vs. 1.46 ± 1.56 mg L(-1) , P = 0.0001) was lower in the CR group. Trabecular bone microarchitecture parameters such as the erosion index (0.916 ± 0.087 vs. 0.877 ± 0.088; P = 0.739) and surface-to-curve ratio (10.3 ± 1.4 vs. 12.1 ± 2.1, P = 0.440) were not significantly different between groups. These findings suggest that markedly reduced BMD is not associated with significantly reduced bone quality in middle-aged men and women practicing long-term calorie restriction with adequate nutrition.

GenBank blastx search result: AK104368 [KOME

Lifescience Database Archive (English)

Full Text Available AK104368 001-035-E04 AF085721.2 Ureaplasma urealyticum serovar 4 urease complex component UreA (ureA), ureas...e complex component UreB (ureB), urease complex component UreC (ureC), urease compl...ex component UreE (ureE), urease complex component UreF (ureF), urease complex component UreG (ureG), and urease

GenBank blastx search result: AK104368 [KOME

Lifescience Database Archive (English)

Full Text Available AK104368 001-035-E04 AF085733.2 Ureaplasma parvum serovar 14 urease complex component UreA (ureA), urease... complex component UreB (ureB), urease complex component UreC (ureC), urease complex component UreE (ureE), ure...ase complex component UreF (ureF), urease complex component UreG (ureG), and urease

GenBank blastx search result: AK104368 [KOME

Lifescience Database Archive (English)

Full Text Available AK104368 001-035-E04 AF085728.2 Ureaplasma urealyticum serovar 12 urease complex component UreA (ureA), urea...se complex component UreB (ureB), urease complex component UreC (ureC), urease comp...lex component UreE (ureE), urease complex component UreF (ureF), urease complex component UreG (ureG), and urease

GenBank blastx search result: AK104368 [KOME

Lifescience Database Archive (English)

Full Text Available AK104368 001-035-E04 AF085731.2 Ureaplasma parvum serovar 1 urease complex component UreA (ureA), urease... complex component UreB (ureB), urease complex component UreC (ureC), urease complex component UreE (ureE), urea...se complex component UreF (ureF), urease complex component UreG (ureG), and urease

GenBank blastx search result: AK104368 [KOME

Lifescience Database Archive (English)

Full Text Available AK104368 001-035-E04 AF085720.2 Ureaplasma urealyticum serovar 2 urease complex component UreA (ureA), ureas...e complex component UreB (ureB), urease complex component UreC (ureC), urease compl...ex component UreE (ureE), urease complex component UreF (ureF), urease complex component UreG (ureG), and urease

GenBank blastx search result: AK104368 [KOME

Lifescience Database Archive (English)

Full Text Available AK104368 001-035-E04 AF085727.2 Ureaplasma urealyticum serovar 11 urease complex component UreA (ureA), urea...se complex component UreB (ureB), urease complex component UreC (ureC), urease comp...lex component UreE (ureE), urease complex component UreF (ureF), urease complex component UreG (ureG), and urease

GenBank blastx search result: AK104368 [KOME

Lifescience Database Archive (English)

Full Text Available AK104368 001-035-E04 AF085722.2 Ureaplasma urealyticum serovar 5 urease complex component UreA (ureA), ureas...e complex component UreB (ureB), urease complex component UreC (ureC), urease compl...ex component UreE (ureE), urease complex component UreF (ureF), urease complex component UreG (ureG), and urease

GenBank blastx search result: AK104368 [KOME

Lifescience Database Archive (English)

Full Text Available AK104368 001-035-E04 AF085730.2 Ureaplasma parvum serovar 6 urease complex component UreA (ureA), urease... complex component UreB (ureB), urease complex component UreC (ureC), urease complex component UreE (ureE), urea...se complex component UreF (ureF), urease complex component UreG (ureG), and urease

GenBank blastx search result: AK104368 [KOME

Lifescience Database Archive (English)

Full Text Available AK104368 001-035-E04 AF085724.2 Ureaplasma urealyticum serovar 8 urease complex component UreA (ureA), ureas...e complex component UreB (ureB), urease complex component UreC (ureC), urease compl...ex component UreE (ureE), urease complex component UreF (ureF), urease complex component UreG (ureG), and urease

GenBank blastx search result: AK104368 [KOME

Lifescience Database Archive (English)

Full Text Available AK104368 001-035-E04 AF085723.2 Ureaplasma urealyticum serovar 7 urease complex component UreA (ureA), ureas...e complex component UreB (ureB), urease complex component UreC (ureC), urease compl...ex component UreE (ureE), urease complex component UreF (ureF), urease complex component UreG (ureG), and urease

GenBank blastx search result: AK104368 [KOME

Lifescience Database Archive (English)

Full Text Available AK104368 001-035-E04 AF085729.2 Ureaplasma urealyticum serovar 13 urease complex component UreA (ureA), urea...se complex component UreB (ureB), urease complex component UreC (ureC), urease comp...lex component UreE (ureE), urease complex component UreF (ureF), urease complex component UreG (ureG), and urease

GenBank blastx search result: AK104368 [KOME

Lifescience Database Archive (English)

Full Text Available AK104368 001-035-E04 AF085725.2 Ureaplasma urealyticum serovar 9 urease complex component UreA (ureA), ureas...e complex component UreB (ureB), urease complex component UreC (ureC), urease compl...ex component UreE (ureE), urease complex component UreF (ureF), urease complex component UreG (ureG), and urease

GenBank blastx search result: AK104368 [KOME

Lifescience Database Archive (English)

Full Text Available AK104368 001-035-E04 AF085726.2 Ureaplasma urealyticum serovar 10 urease complex component UreA (ureA), urea...se complex component UreB (ureB), urease complex component UreC (ureC), urease comp...lex component UreE (ureE), urease complex component UreF (ureF), urease complex component UreG (ureG), and urease

GenBank blastx search result: AK104368 [KOME

Lifescience Database Archive (English)

Full Text Available AK104368 001-035-E04 AF361941.1 Brucella melitensis biovar Abortus urease accessory protein UreD (ureD), ure...ase gamma subunit UreA (ureA), urease beta subunit UreB (ureB), urease alpha subunit UreC (ureC), urease... accessory protein UreE (ureE), urease accessory protein UreF (ureF), and urease access

Nutritional upgrading for omnivorous carpenter ants by the endosymbiont Blochmannia

Directory of Open Access Journals (Sweden)

Mueller Martin J

2007-10-01

Full Text Available Abstract Background Carpenter ants (genus Camponotus are considered to be omnivores. Nonetheless, the genome sequence of Blochmannia floridanus, the obligate intracellular endosymbiont of Camponotus floridanus, suggests a function in nutritional upgrading of host resources by the bacterium. Thus, the strongly reduced genome of the endosymbiont retains genes for all subunits of a functional urease, as well as those for biosynthetic pathways for all but one (arginine of the amino acids essential to the host. Results Nutritional upgrading by Blochmannia was tested in 90-day feeding experiments with brood-raising in worker-groups on chemically defined diets with and without essential amino acids and treated or not with antibiotics. Control groups were fed with cockroaches, honey water and Bhatkar agar. Worker-groups were provided with brood collected from the queenright mother-colonies (45 eggs and 45 first instar larvae each. Brood production did not differ significantly between groups of symbiotic workers on diets with and without essential amino acids. However, aposymbiotic worker groups raised significantly less brood on a diet lacking essential amino acids. Reduced brood production by aposymbiotic workers was compensated when those groups were provided with essential amino acids in their diet. Decrease of endosymbionts due to treatment with antibiotic was monitored by qRT-PCR and FISH after the 90-day experimental period. Urease function was confirmed by feeding experiments using 15N-labelled urea. GC-MS analysis of 15N-enrichment of free amino acids in workers revealed significant labelling of the non-essential amino acids alanine, glycine, aspartic acid, and glutamic acid, as well as of the essential amino acids methionine and phenylalanine. Conclusion Our results show that endosymbiotic Blochmannia nutritionally upgrade the diet of C. floridanus hosts to provide essential amino acids, and that it may also play a role in nitrogen recycling

Mindfulness significantly reduces self-reported levels of anxiety and depression

DEFF Research Database (Denmark)

Würtzen, Hanne; Dalton, Susanne Oksbjerg; Elsass, Peter

2013-01-01

INTRODUCTION: As the incidence of and survival from breast cancer continue to raise, interventions to reduce anxiety and depression before, during and after treatment are needed. Previous studies have reported positive effects of a structured 8-week group mindfulness-based stress reduction program...

Diversity of organotrophic bacteria, activity of dehydrogenases and urease as well as seed germination and root growth Lepidium sativum, Sorghum saccharatum and Sinapis alba under the influence of polycyclic aromatic hydrocarbons.

Science.gov (United States)

Lipińska, Aneta; Wyszkowska, Jadwiga; Kucharski, Jan

2015-12-01

Polycyclic aromatic hydrocarbons are organic compounds with highly toxic, carcinogenic, and mutagenic properties, which adversely affect the basic biological parameters of the soil, including the count of microorganisms, and the enzymatic activity. In addition to disturbances to the biological activity of the soil, PAHs may also exhibit toxic effects on plants. In view of the above, the study involved testing aimed at the determination of the effects of polycyclic aromatic hydrocarbons in a form of naphthalene, phenanthrene, anthracene and pyrene on the count, colony development (CD) index, ecophysiological (EP) diversity index of organotrophic bacteria, and the activity of soil dehydrogenases and soil urease. Moreover, an attempt was made to determine the soil's resistance based on the activity of the above-listed enzymes, and the effect of polycyclic aromatic hydrocarbons on seed germination and root growth was assessed by Lepidium sativum, Sorghum saccharatum, and Sinapis alba. In addition, the species of bacteria found in a soil subjected to strong pressure of polycyclic aromatic hydrocarbons were isolated. The experiment was performed in a laboratory on samples of loamy sand. Polycyclic aromatic hydrocarbons were introduced into the soil in an amount of 0, 1000, 2000, and 4000 mg kg(-1) of soil dry matter. Germination and growth of cress (L. sativum), white mustard (S. alba), and sweet sorghum (S. saccharatum) were determined using Phytotoxkit tests. It was found that the tested PAHs increased the average colony counts of organotrophic soil bacteria; pyrene did so to the greatest extent (2.2-fold relative to non-contaminated soil), phenanthrene to the smallest extent (1.4-fold relative to non-contaminated soil). None of the PAHs changed the value of the bacterial colony development (CD) index, while anthracene and pyrene increased the value of the eco-physiological (EP) diversity indicator. PAHs lowered the activity of the tested enzymes. The activity of

Reduced content of chloroatranol and atranol in oak moss absolute significantly reduces the elicitation potential of this fragrance material.

Science.gov (United States)

Andersen, Flemming; Andersen, Kirsten H; Bernois, Armand; Brault, Christophe; Bruze, Magnus; Eudes, Hervé; Gadras, Catherine; Signoret, Anne-Cécile J; Mose, Kristian F; Müller, Boris P; Toulemonde, Bernard; Andersen, Klaus Ejner

2015-02-01

Oak moss absolute, an extract from the lichen Evernia prunastri, is a valued perfume ingredient but contains extreme allergens. To compare the elicitation properties of two preparations of oak moss absolute: 'classic oak moss', the historically used preparation, and 'new oak moss', with reduced contents of the major allergens atranol and chloroatranol. The two preparations were compared in randomized double-blinded repeated open application tests and serial dilution patch tests in 30 oak moss-sensitive volunteers and 30 non-allergic control subjects. In both test models, new oak moss elicited significantly less allergic contact dermatitis in oak moss-sensitive subjects than classic oak moss. The control subjects did not react to either of the preparations. New oak moss is still a fragrance allergen, but elicits less allergic contact dermatitis in previously oak moss-sensitized individuals, suggesting that new oak moss is less allergenic to non-sensitized individuals. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

GenBank blastx search result: AK104368 [KOME

Lifescience Database Archive (English)

Full Text Available AK104368 001-035-E04 AF056189.1 Synechococcus WH7805 urease accessory protein UreG (ureG), urease... accessory protein UreF (ureF), urease accessory protein UreE (ureE), urease accessory protein UreD (ureD), urease... gamma subunit (ureA), urease beta subunit (ureB), and urease alpha subunit (ureC) genes, complete cds.|BCT BCT 1e-59 +1 ...

GenBank blastx search result: AK104200 [KOME

Lifescience Database Archive (English)

Full Text Available AK104200 006-304-B01 AF056189.1 Synechococcus WH7805 urease accessory protein UreG (ureG), urease... accessory protein UreF (ureF), urease accessory protein UreE (ureE), urease accessory protein UreD (ureD), urease... gamma subunit (ureA), urease beta subunit (ureB), and urease alpha subunit (ureC) genes, complete cds.|BCT BCT 1e-59 +1 ...

Brucella abortus ure2 region contains an acid-activated urea transporter and a nickel transport system

Directory of Open Access Journals (Sweden)

García-Lobo Juan M

2010-04-01

Full Text Available Abstract Background Urease is a virulence factor that plays a role in the resistance of Brucella to low pH conditions, both in vivo and in vitro. Brucella contains two separate urease gene clusters, ure1 and ure2. Although only ure1 codes for an active urease, ure2 is also transcribed, but its contribution to Brucella biology is unknown. Results Re-examination of the ure2 locus showed that the operon includes five genes downstream of ureABCEFGDT that are orthologs to a nikKMLQO cluster encoding an ECF-type transport system for nickel. ureT and nikO mutants were constructed and analyzed for urease activity and acid resistance. A non-polar ureT mutant was unaffected in urease activity at neutral pH but showed a significantly decreased activity at acidic pH. It also showed a decreased survival rate to pH 2 at low concentration of urea when compared to the wild type. The nikO mutant had decreased urease activity and acid resistance at all urea concentrations tested, and this phenotype could be reverted by the addition of nickel to the growth medium. Conclusions Based on these results, we concluded that the operon ure2 codes for an acid-activated urea transporter and a nickel transporter necessary for the maximal activity of the urease whose structural subunits are encoded exclusively by the genes in the ure1 operon.

Next-generation nozzle check valve significantly reduces operating costs

Energy Technology Data Exchange (ETDEWEB)

Roorda, O. [SMX International, Toronto, ON (Canada)

2009-01-15

Check valves perform an important function in preventing reverse flow and protecting plant and mechanical equipment. However, the variety of different types of valves and extreme differences in performance even within one type can change maintenance requirements and life cycle costs, amounting to millions of dollars over the typical 15-year design life of piping components. A next-generation non-slam nozzle check valve which prevents return flow has greatly reduced operating costs by protecting the mechanical equipment in a piping system. This article described the check valve varieties such as the swing check valve, a dual-plate check valve, and nozzle check valves. Advancements in optimized design of a non-slam nozzle check valve were also discussed, with particular reference to computer flow modelling such as computational fluid dynamics; computer stress modelling such as finite element analysis; and flow testing (using rapid prototype development and flow loop testing), both to improve dynamic performance and reduce hydraulic losses. The benefits of maximized dynamic performance and minimized pressure loss from the new designed valve were also outlined. It was concluded that this latest non-slam nozzle check valve design has potential applications in natural gas, liquefied natural gas, and oil pipelines, including subsea applications, as well as refineries, and petrochemical plants among others, and is suitable for horizontal and vertical installation. The result of this next-generation nozzle check valve design is not only superior performance, and effective protection of mechanical equipment but also minimized life cycle costs. 1 fig.

GenBank blastx search result: AK104368 [KOME

Lifescience Database Archive (English)

Full Text Available , ureE, ureF genes for urease beta subunit UreB, urease alpha subunit UreC, urease gamma subunit UreA, urease... accessory protein UreG, urease accessory protein UreD, urease accessory protein UreE, urease accessory protein UreF, complete cds.|BCT BCT 1e-46 +1 ... ...AK104368 001-035-E04 AB119092.1 Haloarcula marismortui ureB, ureC, ureA, ureG, ureD

GenBank blastx search result: AK104368 [KOME

Lifescience Database Archive (English)

Full Text Available AK104368 001-035-E04 AF056321.1 Actinomyces naeslundii urease gamma subunit UreA (ureA), urease... beta subunit UreB (ureB), urease alpha subunit UreC (ureC), urease accessory protein UreE (ureE), urease... accessory protein UreF (ureF), urease accessory protein UreG (ureG), and urease accessory protein UreD (ureD) genes, complete cds.|BCT BCT 3e-48 +1 ...

Characterization of Recombinant, Ureolytic Streptococcus mutans Demonstrates an Inverse Relationship between Dental Plaque Ureolytic Capacity and Cariogenicity

Science.gov (United States)

Clancy, K. Anne; Pearson, Sylvia; Bowen, William H.; Burne, Robert A.

2000-01-01

Dental caries results from prolonged plaque acidification that leads to the establishment of a cariogenic microflora and demineralization of the tooth. Urease enzymes of oral bacteria hydrolyze urea to ammonia, which can neutralize plaque acids. To begin to examine the relationship between plaque ureolytic activity and the incidence of dental caries, recombinant, ureolytic strains of Streptococcus mutans were constructed. Specifically, the ureABCEFGD operon from Streptococcus salivarius 57.I was integrated into the S. mutans chromosome in such a way that the operon was transcribed from a weak, cognate promoter in S. mutans ACUS4 or a stronger promoter in S. mutans ACUS6. Both strains expressed NiCl2-dependent urease activity, but the maximal urease levels in ACUS6 were threefold higher than those in ACUS4. In vitro pH drop experiments demonstrated that the ability of the recombinant S. mutans strains to moderate a decrease in pH during the simultaneous metabolism of glucose and urea increased proportionately with the level of urease activity expressed. Specific-pathogen-free rats that were infected with ACUS6 and fed a cariogenic diet with drinking water containing 25 mM urea and 50 μM NiCl2 had relatively high levels of oral urease activity, as well as dramatic decreases in the prevalence of smooth-surface caries and the severity of sulcal caries, relative to controls. Urease activity appears to influence plaque biochemistry and metabolism in a manner that reduces cariogenicity, suggesting that recombinant, ureolytic bacteria may be useful to promote dental health. PMID:10768953

Intriguing model significantly reduces boarding of psychiatric patients, need for inpatient hospitalization.

Science.gov (United States)

2015-01-01

As new approaches to the care of psychiatric emergencies emerge, one solution is gaining particular traction. Under the Alameda model, which has been put into practice in Alameda County, CA, patients who are brought to regional EDs with emergency psychiatric issues are quickly transferred to a designated emergency psychiatric facility as soon as they are medically stabilized. This alleviates boarding problems in area EDs while also quickly connecting patients with specialized care. With data in hand on the model's effectiveness, developers believe the approach could alleviate boarding problems in other communities as well. The model is funded by through a billing code established by California's Medicaid program for crisis stabilization services. Currently, only 22% of the patients brought to the emergency psychiatric facility ultimately need to be hospitalized; the other 78% are able to go home or to an alternative situation. In a 30-day study of the model, involving five community hospitals in Alameda County, CA, researchers found that ED boarding times were as much as 80% lower than comparable ED averages, and that patients were stabilized at least 75% of the time, significantly reducing the need for inpatient hospitalization.

Significant association between sulfate-reducing bacteria and uranium-reducing microbial communities as revealed by a combined massively parallel sequencing-indicator species approach.

Science.gov (United States)

Cardenas, Erick; Wu, Wei-Min; Leigh, Mary Beth; Carley, Jack; Carroll, Sue; Gentry, Terry; Luo, Jian; Watson, David; Gu, Baohua; Ginder-Vogel, Matthew; Kitanidis, Peter K; Jardine, Philip M; Zhou, Jizhong; Criddle, Craig S; Marsh, Terence L; Tiedje, James M

2010-10-01

Massively parallel sequencing has provided a more affordable and high-throughput method to study microbial communities, although it has mostly been used in an exploratory fashion. We combined pyrosequencing with a strict indicator species statistical analysis to test if bacteria specifically responded to ethanol injection that successfully promoted dissimilatory uranium(VI) reduction in the subsurface of a uranium contamination plume at the Oak Ridge Field Research Center in Tennessee. Remediation was achieved with a hydraulic flow control consisting of an inner loop, where ethanol was injected, and an outer loop for flow-field protection. This strategy reduced uranium concentrations in groundwater to levels below 0.126 μM and created geochemical gradients in electron donors from the inner-loop injection well toward the outer loop and downgradient flow path. Our analysis with 15 sediment samples from the entire test area found significant indicator species that showed a high degree of adaptation to the three different hydrochemical-created conditions. Castellaniella and Rhodanobacter characterized areas with low pH, heavy metals, and low bioactivity, while sulfate-, Fe(III)-, and U(VI)-reducing bacteria (Desulfovibrio, Anaeromyxobacter, and Desulfosporosinus) were indicators of areas where U(VI) reduction occurred. The abundance of these bacteria, as well as the Fe(III) and U(VI) reducer Geobacter, correlated with the hydraulic connectivity to the substrate injection site, suggesting that the selected populations were a direct response to electron donor addition by the groundwater flow path. A false-discovery-rate approach was implemented to discard false-positive results by chance, given the large amount of data compared.

Lime and Phosphate Amendment Can Significantly Reduce Uptake of Cd and Pb by Field-Grown Rice

Directory of Open Access Journals (Sweden)

Rongbo Xiao

2017-03-01

Full Text Available Agricultural soils are suffering from increasing heavy metal pollution, among which, paddy soil polluted by heavy metals is frequently reported and has elicited great public concern. In this study, we carried out field experiments on paddy soil around a Pb-Zn mine to study amelioration effects of four soil amendments on uptake of Cd and Pb by rice, and to make recommendations for paddy soil heavy metal remediation, particularly for combined pollution of Cd and Pb. The results showed that all the four treatments can significantly reduce the Cd and Pb content in the late rice grain compared with the early rice, among which, the combination amendment of lime and phosphate had the best remediation effects where rice grain Cd content was reduced by 85% and 61%, respectively, for the late rice and the early rice, and by 30% in the late rice grain for Pb. The high reduction effects under the Ca + P treatment might be attributed to increase of soil pH from 5.5 to 6.7. We also found that influence of the Ca + P treatment on rice production was insignificant, while the available Cd and Pb content in soil was reduced by 16.5% and 11.7%, respectively.

Soil Enzyme Activities in Pinus tabuliformis (Carriére Plantations in Northern China

Directory of Open Access Journals (Sweden)

Weiwei Wang

2016-05-01

Full Text Available Changes in forest stand structure may alter the activity of invertase, urease, catalase and phenol oxidase after thinning Pinus tabuliformis (Carriére plantations in Yanqing County of Beijing, China. We examined changes in these soil enzymes as influenced by time since thinning (24, 32, and 40 years since thinning for 3 seasons (spring, summer and autumn following harvesting at two depths in the mineral soil (0–10 cm and 10–20 cm. Invertase and urease increased significantly with time since thinning. Catalase activity was highest in the 24-year-old stand and there were no statistically significant differences between the 32- and 40-year-old stands. In addition, maximum invertase, urease, catalase, and phenol oxidase activities occurred during the summer; minimum activities occurred in autumn. Invertase and urease were positively correlated with each other, as were catalase and phenol oxidase. Most soil enzyme activity was higher in the 0–10 cm layer than at the 10–20 cm depth. As time from thinning increased, differences among soil depth became less significant. These results suggest that seasonal changes of these enzymes have different roles, as the time since thinning and thinning treatments may have both short- and long-term impacts on soil microbial activity.

Incorporation of catalytic dehydrogenation into fischer-tropsch synthesis to significantly reduce carbon dioxide emissions

Science.gov (United States)

Huffman, Gerald P.

2012-11-13

A new method of producing liquid transportation fuels from coal and other hydrocarbons that significantly reduces carbon dioxide emissions by combining Fischer-Tropsch synthesis with catalytic dehydrogenation is claimed. Catalytic dehydrogenation (CDH) of the gaseous products (C1-C4) of Fischer-Tropsch synthesis (FTS) can produce large quantities of hydrogen while converting the carbon to multi-walled carbon nanotubes (MWCNT). Incorporation of CDH into a FTS-CDH plant converting coal to liquid fuels can eliminate all or most of the CO.sub.2 emissions from the water-gas shift (WGS) reaction that is currently used to elevate the H.sub.2 level of coal-derived syngas for FTS. Additionally, the FTS-CDH process saves large amounts of water used by the WGS reaction and produces a valuable by-product, MWCNT.

Polymerase chain reaction-hybridization method using urease gene sequences for high-throughput Ureaplasma urealyticum and Ureaplasma parvum detection and differentiation.

Science.gov (United States)

Xu, Chen; Zhang, Nan; Huo, Qianyu; Chen, Minghui; Wang, Rengfeng; Liu, Zhili; Li, Xue; Liu, Yunde; Bao, Huijing

2016-04-15

In this article, we discuss the polymerase chain reaction (PCR)-hybridization assay that we developed for high-throughput simultaneous detection and differentiation of Ureaplasma urealyticum and Ureaplasma parvum using one set of primers and two specific DNA probes based on urease gene nucleotide sequence differences. First, U. urealyticum and U. parvum DNA samples were specifically amplified using one set of biotin-labeled primers. Furthermore, amine-modified DNA probes, which can specifically react with U. urealyticum or U. parvum DNA, were covalently immobilized to a DNA-BIND plate surface. The plate was then incubated with the PCR products to facilitate sequence-specific DNA binding. Horseradish peroxidase-streptavidin conjugation and a colorimetric assay were used. Based on the results, the PCR-hybridization assay we developed can specifically differentiate U. urealyticum and U. parvum with high sensitivity (95%) compared with cultivation (72.5%). Hence, this study demonstrates a new method for high-throughput simultaneous differentiation and detection of U. urealyticum and U. parvum with high sensitivity. Based on these observations, the PCR-hybridization assay developed in this study is ideal for detecting and discriminating U. urealyticum and U. parvum in clinical applications. Copyright © 2016 Elsevier Inc. All rights reserved.

Improved strength and durability of concrete through metabolic activity of ureolytic bacteria.

Science.gov (United States)

Alonso, Maria Jose Castro; Ortiz, Carlos Eloir Lopez; Perez, Sixto Omar Garcia; Narayanasamy, Rajeswari; Fajardo San Miguel, Gerardo Del Jesús; Hernández, Héctor Herrera; Balagurusamy, Nagamani

2017-06-07

In recent years, biomineralization process is being employed in development of bioconcrete, which is emerging as a sustainable method to enhance the durability of concrete by way of increasing compressive strength and reducing the chloride permeability. In this study, different bacterial strains isolated from the soils of the Laguna Region of Mexico were selected for further study. ACRN5 strain demonstrated higher urease activity than other strains, and the optimum substrate concentration, pH, and temperature were 120 mM, pH 8, and 25 °C, respectively. Further, Km and Vmax of urease activity of ACRN5 were 21.38 mM and 0.212 mM min -1 , respectively. It was observed that addition of ACRN5 at 10 5  cells ml -1 to cement-water mixture significantly increased (14.94%) in compressive strength after 36 days of curing and reduced chloride penetration. Deposition of calcite in bio-mortars was observed in scanning electron microscopy and energy dispersive X-ray diffraction spectrometry analyses. Results of this study demonstrated the role of microbially induced calcium carbonate precipitation in improving the physico-mechanical properties of bio-mortars.

Interaction between FOXO1A-209 Genotype and Tea Drinking is Significantly Associated with Reduced Mortality at Advanced Ages

DEFF Research Database (Denmark)

Zeng, Yi; Chen, Huashuai; Ni, Ting

2016-01-01

Based on the genotypic/phenotypic data from Chinese Longitudinal Healthy Longevity Survey (CLHLS) and Cox proportional hazard model, the present study demonstrates that interactions between carrying FOXO1A-209 genotypes and tea drinking are significantly associated with lower risk of mortality...... at advanced ages. Such significant association is replicated in two independent Han Chinese CLHLS cohorts (p =0.028-0.048 in the discovery and replication cohorts, and p =0.003-0.016 in the combined dataset). We found the associations between tea drinking and reduced mortality are much stronger among carriers...... of the FOXO1A-209 genotype compared to non-carriers, and drinking tea is associated with a reversal of the negative effects of carrying FOXO1A-209 minor alleles, that is, from a substantially increased mortality risk to substantially reduced mortality risk at advanced ages. The impacts are considerably...

Induction-heating MOCVD reactor with significantly improved heating efficiency and reduced harmful magnetic coupling

KAUST Repository

Li, Kuang-Hui; Alotaibi, Hamad S.; Sun, Haiding; Lin, Ronghui; Guo, Wenzhe; Torres-Castanedo, Carlos G.; Liu, Kaikai; Galan, Sergio V.; Li, Xiaohang

2018-01-01

In a conventional induction-heating III-nitride metalorganic chemical vapor deposition (MOCVD) reactor, the induction coil is outside the chamber. Therefore, the magnetic field does not couple with the susceptor well, leading to compromised heating efficiency and harmful coupling with the gas inlet and thus possible overheating. Hence, the gas inlet has to be at a minimum distance away from the susceptor. Because of the elongated flow path, premature reactions can be more severe, particularly between Al- and B-containing precursors and NH3. Here, we propose a structure that can significantly improve the heating efficiency and allow the gas inlet to be closer to the susceptor. Specifically, the induction coil is designed to surround the vertical cylinder of a T-shaped susceptor comprising the cylinder and a top horizontal plate holding the wafer substrate within the reactor. Therefore, the cylinder coupled most magnetic field to serve as the thermal source for the plate. Furthermore, the plate can block and thus significantly reduce the uncoupled magnetic field above the susceptor, thereby allowing the gas inlet to be closer. The results show approximately 140% and 2.6 times increase in the heating and susceptor coupling efficiencies, respectively, as well as a 90% reduction in the harmful magnetic flux on the gas inlet.

Induction-heating MOCVD reactor with significantly improved heating efficiency and reduced harmful magnetic coupling

KAUST Repository

Li, Kuang-Hui

2018-02-23

In a conventional induction-heating III-nitride metalorganic chemical vapor deposition (MOCVD) reactor, the induction coil is outside the chamber. Therefore, the magnetic field does not couple with the susceptor well, leading to compromised heating efficiency and harmful coupling with the gas inlet and thus possible overheating. Hence, the gas inlet has to be at a minimum distance away from the susceptor. Because of the elongated flow path, premature reactions can be more severe, particularly between Al- and B-containing precursors and NH3. Here, we propose a structure that can significantly improve the heating efficiency and allow the gas inlet to be closer to the susceptor. Specifically, the induction coil is designed to surround the vertical cylinder of a T-shaped susceptor comprising the cylinder and a top horizontal plate holding the wafer substrate within the reactor. Therefore, the cylinder coupled most magnetic field to serve as the thermal source for the plate. Furthermore, the plate can block and thus significantly reduce the uncoupled magnetic field above the susceptor, thereby allowing the gas inlet to be closer. The results show approximately 140% and 2.6 times increase in the heating and susceptor coupling efficiencies, respectively, as well as a 90% reduction in the harmful magnetic flux on the gas inlet.

A Recombinant Multi-Stage Vaccine against Paratuberculosis Significantly Reduces Bacterial Level in Tissues without Interference in Diagnostics

DEFF Research Database (Denmark)

Jungersen, Gregers; Thakur, Aneesh; Aagaard, C.

, PPDj-specific IFN-γ responses or positive PPDa or PPDb skin tests developed in vaccinees. Antibodies and cell-mediated immune responses were developed against FET11 antigens, however. At necropsy 8 or 12 months of age, relative Map burden was determined in a number of gut tissues by quantitative IS900...... PCR and revealed significantly reduced levels of Map and reduced histopathology. Diagnostic tests for antibody responses and cell-mediated immune responses, used as surrogates of infection, corroborated the observed vaccine efficacy: Five of seven non‐vaccinated calves seroconverted in ID Screen......-γ assay responses from 40 to 52 weeks compared to non-vaccinated calves. These results indicate the FET11 vaccine can be used to accelerate eradication of paratuberculosis while surveillance or test-and-manage control programs for tuberculosis and Johne’s disease remain in place. Funded by EMIDA ERA...

Significant Association between Sulfate-Reducing Bacteria and Uranium-Reducing Microbial Communities as Revealed by a Combined Massively Parallel Sequencing-Indicator Species Approach▿ †

Science.gov (United States)

Cardenas, Erick; Wu, Wei-Min; Leigh, Mary Beth; Carley, Jack; Carroll, Sue; Gentry, Terry; Luo, Jian; Watson, David; Gu, Baohua; Ginder-Vogel, Matthew; Kitanidis, Peter K.; Jardine, Philip M.; Zhou, Jizhong; Criddle, Craig S.; Marsh, Terence L.; Tiedje, James M.

2010-01-01

Massively parallel sequencing has provided a more affordable and high-throughput method to study microbial communities, although it has mostly been used in an exploratory fashion. We combined pyrosequencing with a strict indicator species statistical analysis to test if bacteria specifically responded to ethanol injection that successfully promoted dissimilatory uranium(VI) reduction in the subsurface of a uranium contamination plume at the Oak Ridge Field Research Center in Tennessee. Remediation was achieved with a hydraulic flow control consisting of an inner loop, where ethanol was injected, and an outer loop for flow-field protection. This strategy reduced uranium concentrations in groundwater to levels below 0.126 μM and created geochemical gradients in electron donors from the inner-loop injection well toward the outer loop and downgradient flow path. Our analysis with 15 sediment samples from the entire test area found significant indicator species that showed a high degree of adaptation to the three different hydrochemical-created conditions. Castellaniella and Rhodanobacter characterized areas with low pH, heavy metals, and low bioactivity, while sulfate-, Fe(III)-, and U(VI)-reducing bacteria (Desulfovibrio, Anaeromyxobacter, and Desulfosporosinus) were indicators of areas where U(VI) reduction occurred. The abundance of these bacteria, as well as the Fe(III) and U(VI) reducer Geobacter, correlated with the hydraulic connectivity to the substrate injection site, suggesting that the selected populations were a direct response to electron donor addition by the groundwater flow path. A false-discovery-rate approach was implemented to discard false-positive results by chance, given the large amount of data compared. PMID:20729318

Pegasus project. DLC coating and low viscosity oil reduce energy losses significantly

Energy Technology Data Exchange (ETDEWEB)

Doerwald, Dave; Jacobs, Ruud [Hauzer Techno Coating (Netherlands). Tribological Coatings

2012-03-15

Pegasus, the flying horse from Greek mythology, is a suitable name for the research project initiated by a German automotive OEM with participation of Hauzer Techno Coating and several automotive suppliers. It will enable future automotive vehicles to reduce fuel consumption without losing power. The project described in this article focuses on the rear differential, because reducing friction here can contribute considerably to efficiency improvement of the whole vehicle. Surfaces, coating and oil viscosity have been investigated and interesting conclusions have been reached. (orig.)

Implementation of standardized follow-up care significantly reduces peritonitis in children on chronic peritoneal dialysis.

Science.gov (United States)

Neu, Alicia M; Richardson, Troy; Lawlor, John; Stuart, Jayne; Newland, Jason; McAfee, Nancy; Warady, Bradley A

2016-06-01

The Standardizing Care to improve Outcomes in Pediatric End stage renal disease (SCOPE) Collaborative aims to reduce peritonitis rates in pediatric chronic peritoneal dialysis patients by increasing implementation of standardized care practices. To assess this, monthly care bundle compliance and annualized monthly peritonitis rates were evaluated from 24 SCOPE centers that were participating at collaborative launch and that provided peritonitis rates for the 13 months prior to launch. Changes in bundle compliance were assessed using either a logistic regression model or a generalized linear mixed model. Changes in average annualized peritonitis rates over time were illustrated using the latter model. In the first 36 months of the collaborative, 644 patients with 7977 follow-up encounters were included. The likelihood of compliance with follow-up care practices increased significantly (odds ratio 1.15, 95% confidence interval 1.10, 1.19). Mean monthly peritonitis rates significantly decreased from 0.63 episodes per patient year (95% confidence interval 0.43, 0.92) prelaunch to 0.42 (95% confidence interval 0.31, 0.57) at 36 months postlaunch. A sensitivity analysis confirmed that as mean follow-up compliance increased, peritonitis rates decreased, reaching statistical significance at 80% at which point the prelaunch rate was 42% higher than the rate in the months following achievement of 80% compliance. In its first 3 years, the SCOPE Collaborative has increased the implementation of standardized follow-up care and demonstrated a significant reduction in average monthly peritonitis rates. Copyright © 2016 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.

Significantly reduced c-axis thermal diffusivity of graphene-based papers

Science.gov (United States)

Han, Meng; Xie, Yangsu; Liu, Jing; Zhang, Jingchao; Wang, Xinwei

2018-06-01

Owing to their very high thermal conductivity as well as large surface-to-volume ratio, graphene-based films/papers have been proposed as promising candidates of lightweight thermal interface materials and lateral heat spreaders. In this work, we study the cross-plane (c-axis) thermal conductivity (k c ) and diffusivity (α c ) of two typical graphene-based papers, which are partially reduced graphene paper (PRGP) and graphene oxide paper (GOP), and compare their thermal properties with highly-reduced graphene paper and graphite. The determined α c of PRGP varies from (1.02 ± 0.09) × 10‑7 m2 s‑1 at 295 K to (2.31 ± 0.18) × 10‑7 m2 s‑1 at 12 K. This low α c is mainly attributed to the strong phonon scattering at the grain boundaries and defect centers due to the small grain sizes and high-level defects. For GOP, α c varies from (1.52 ± 0.05) × 10‑7 m2 s‑1 at 295 K to (2.28 ± 0.08) × 10‑7 m2 s‑1 at 12.5 K. The cross-plane thermal transport of GOP is attributed to the high density of functional groups between carbon layers which provide weak thermal transport tunnels across the layers in the absence of direct energy coupling among layers. This work sheds light on the understanding and optimizing of nanostructure of graphene-based paper-like materials for desired thermal performance.

Molecular identification and characterization of clustered regularly interspaced short palindromic repeats (CRISPRs) in a urease-positive thermophilic Campylobacter sp. (UPTC).

Science.gov (United States)

Tasaki, E; Hirayama, J; Tazumi, A; Hayashi, K; Hara, Y; Ueno, H; Moore, J E; Millar, B C; Matsuda, M

2012-02-01

Novel clustered regularly-interspaced short palindromic repeats (CRISPRs) locus [7,500 base pairs (bp) in length] occurred in the urease-positive thermophilic Campylobacter (UPTC) Japanese isolate, CF89-12. The 7,500 bp gene loci consisted of the 5'-methylaminomethyl-2-thiouridylate methyltransferase gene, putative (P) CRISPR associated (p-Cas), putative open reading frames, Cas1 and Cas2, leader sequence region (146 bp), 12 CRISPRs consensus sequence repeats (each 36 bp) separated by a non-repetitive unique spacer region of similar length (26-31 bp) and the phosphatidyl glycerophosphatase A gene. When the CRISPRs loci in the UPTC CF89-12 and five C. jejuni isolates were compared with one another, these six isolates contained p-Cas, Cas1 and Cas2 within the loci. Four to 12 CRISPRs consensus sequence repeats separated by a non-repetitive unique spacer region occurred in six isolates and the nucleotide sequences of those repeats gave approximately 92-100% similarity with each other. However, no sequence similarity occurred in the unique spacer regions among these isolates. The putative σ(70) transcriptional promoter and the hypothetical ρ-independent terminator structures for the CRISPRs and Cas were detected. No in vivo transcription of p-Cas, Cas1 and Cas2 was confirmed in the UPTC cells.

Monitoring Soil Microbial Activities in Different Cropping Systems Using Combined Methods

Institute of Scientific and Technical Information of China (English)

YUAN Zhimin; LIU Haijun; HAN Jun; SUN Jingjing; WU Xiaoying; YAO Jun

2017-01-01

Cropping activities may affect soil microbial activities and biomass,which would affect C and N cycling in soil and thus the crop yields and quality.In the present study,a combination of microcalorimetric,enzyme activity (sucrase,urease,catalase,and fluorescein diacetate hydrolysis),and real-time polymerase chain reaction (RT-PCR) analyses was used to investigate microbial status of farmland soils,collected from 5 different sites in Huazhong Agriculture University,China.Our results showed that among the 5 sites,both positive and negative impacts of cropping activities on soil microbial activity were observed.Enzyme activity analysis showed that cropping activities reduced soil sucrase and urease activities,which would influence the C and N cycles in soil.Much more attentions should be given to microbial status affected by cropping activities in future.According to the correlation analysis,fluorescein diacetate hydrolysis showed a significantly (P ＜ 0.05) negative correlation with the time to reach the maximum power output (R =--0.898),but a significantly (P ＜ 0.05) positive correlation with bacterial gene copy number (R =0.817).Soil catalase activity also showed a significantly (P ＜ 0.05) positive correlation with bacterial gene copy number (R =0.965).Using combined methods would provide virtual information of soil microbial status.

Stability and enzyme inhibition activities of au nanoparticles using an aqueous extract of clove as a reducing and stabilizing agent

International Nuclear Information System (INIS)

Hameed, A.; Khan, I.; Naz, S.S.; Islam, N.U.

2014-01-01

Gold nanoparticles (AuNPs) were synthesized in one pot using aqueous extract of clove buds (CB) to reduce HAuCl/sub 4/ and stabilize gold in its atomic form at room temperature. To determine the potential of gold nanoparticles with clove buds (AuCB) for in vivo applications, the stability of the nanoparticles was explored as a function of temperature, pH and salt concentration. The suspensions were found to be stable for salt concentrations up to 1 mol/L, temperatures of up to 100 degree C and a pH range of 2-13. Our results indicate that CB exhibited comparable activities to standards of urease and carbonic anhydrase, but its conjugation to Au knocks out the enzyme inhibition activity by about two times. In case of xanthine oxidase activity, CB and its gold Au bio-conjugates (AuCB) are found to be absolutely inactive. (author)

Pharmacological kynurenine 3-monooxygenase enzyme inhibition significantly reduces neuropathic pain in a rat model.

Science.gov (United States)

Rojewska, Ewelina; Piotrowska, Anna; Makuch, Wioletta; Przewlocka, Barbara; Mika, Joanna

2016-03-01

Recent studies have highlighted the involvement of the kynurenine pathway in the pathology of neurodegenerative diseases, but the role of this system in neuropathic pain requires further extensive research. Therefore, the aim of our study was to examine the role of kynurenine 3-monooxygenase (Kmo), an enzyme that is important in this pathway, in a rat model of neuropathy after chronic constriction injury (CCI) to the sciatic nerve. For the first time, we demonstrated that the injury-induced increase in the Kmo mRNA levels in the spinal cord and the dorsal root ganglia (DRG) was reduced by chronic administration of the microglial inhibitor minocycline and that this effect paralleled a decrease in the intensity of neuropathy. Further, minocycline administration alleviated the lipopolysaccharide (LPS)-induced upregulation of Kmo mRNA expression in microglial cell cultures. Moreover, we demonstrated that not only indirect inhibition of Kmo using minocycline but also direct inhibition using Kmo inhibitors (Ro61-6048 and JM6) decreased neuropathic pain intensity on the third and the seventh days after CCI. Chronic Ro61-6048 administration diminished the protein levels of IBA-1, IL-6, IL-1beta and NOS2 in the spinal cord and/or the DRG. Both Kmo inhibitors potentiated the analgesic properties of morphine. In summary, our data suggest that in neuropathic pain model, inhibiting Kmo function significantly reduces pain symptoms and enhances the effectiveness of morphine. The results of our studies show that the kynurenine pathway is an important mediator of neuropathic pain pathology and indicate that Kmo represents a novel pharmacological target for the treatment of neuropathy. Copyright © 2015 Elsevier Ltd. All rights reserved.

Reducing Eating Disorder Onset in a Very High Risk Sample with Significant Comorbid Depression: A Randomized Controlled Trial

Science.gov (United States)

Taylor, C. Barr; Kass, Andrea E.; Trockel, Mickey; Cunning, Darby; Weisman, Hannah; Bailey, Jakki; Sinton, Meghan; Aspen, Vandana; Schecthman, Kenneth; Jacobi, Corinna; Wilfley, Denise E.

2015-01-01

Objective Eating disorders (EDs) are serious problems among college-age women and may be preventable. An indicated on-line eating disorder (ED) intervention, designed to reduce ED and comorbid pathology, was evaluated. Method 206 women (M age = 20 ± 1.8 years; 51% White/Caucasian, 11% African American, 10% Hispanic, 21% Asian/Asian American, 7% other) at very high risk for ED onset (i.e., with high weight/shape concerns plus a history of being teased, current or lifetime depression, and/or non-clinical levels of compensatory behaviors) were randomized to a 10-week, Internet-based, cognitive-behavioral intervention or wait-list control. Assessments included the Eating Disorder Examination (EDE to assess ED onset), EDE-Questionnaire, Structured Clinical Interview for DSM Disorders, and Beck Depression Inventory-II. Results ED attitudes and behaviors improved more in the intervention than control group (p = 0.02, d = 0.31); although ED onset rate was 27% lower, this difference was not significant (p = 0.28, NNT = 15). In the subgroup with highest shape concerns, ED onset rate was significantly lower in the intervention than control group (20% versus 42%, p = 0.025, NNT = 5). For the 27 individuals with depression at baseline, depressive symptomatology improved more in the intervention than control group (p = 0.016, d = 0.96); although ED onset rate was lower in the intervention than control group, this difference was not significant (25% versus 57%, NNT = 4). Conclusions An inexpensive, easily disseminated intervention might reduce ED onset among those at highest risk. Low adoption rates need to be addressed in future research. PMID:26795936

Reducing eating disorder onset in a very high risk sample with significant comorbid depression: A randomized controlled trial.

Science.gov (United States)

Taylor, C Barr; Kass, Andrea E; Trockel, Mickey; Cunning, Darby; Weisman, Hannah; Bailey, Jakki; Sinton, Meghan; Aspen, Vandana; Schecthman, Kenneth; Jacobi, Corinna; Wilfley, Denise E

2016-05-01

Eating disorders (EDs) are serious problems among college-age women and may be preventable. An indicated online eating disorder (ED) intervention, designed to reduce ED and comorbid pathology, was evaluated. 206 women (M age = 20 ± 1.8 years; 51% White/Caucasian, 11% African American, 10% Hispanic, 21% Asian/Asian American, 7% other) at very high risk for ED onset (i.e., with high weight/shape concerns plus a history of being teased, current or lifetime depression, and/or nonclinical levels of compensatory behaviors) were randomized to a 10-week, Internet-based, cognitive-behavioral intervention or waitlist control. Assessments included the Eating Disorder Examination (EDE, to assess ED onset), EDE-Questionnaire, Structured Clinical Interview for DSM Disorders, and Beck Depression Inventory-II. ED attitudes and behaviors improved more in the intervention than control group (p = .02, d = 0.31); although ED onset rate was 27% lower, this difference was not significant (p = .28, NNT = 15). In the subgroup with highest shape concerns, ED onset rate was significantly lower in the intervention than control group (20% vs. 42%, p = .025, NNT = 5). For the 27 individuals with depression at baseline, depressive symptomatology improved more in the intervention than control group (p = .016, d = 0.96); although ED onset rate was lower in the intervention than control group, this difference was not significant (25% vs. 57%, NNT = 4). An inexpensive, easily disseminated intervention might reduce ED onset among those at highest risk. Low adoption rates need to be addressed in future research. (c) 2016 APA, all rights reserved).

PA positioning significantly reduces testicular dose during sacroiliac joint radiography

Energy Technology Data Exchange (ETDEWEB)

Mekis, Nejc [Faculty of Health Sciences, University of Ljubljana (Slovenia); Mc Entee, Mark F., E-mail: mark.mcentee@ucd.i [School of Medicine and Medical Science, University College Dublin 4 (Ireland); Stegnar, Peter [Jozef Stefan International Postgraduate School, Ljubljana (Slovenia)

2010-11-15

Radiation dose to the testes in the antero-posterior (AP) and postero-anterior (PA) projection of the sacroiliac joint (SIJ) was measured with and without a scrotal shield. Entrance surface dose, the dose received by the testicles and the dose area product (DAP) was used. DAP measurements revealed the dose received by the phantom in the PA position is 12.6% lower than the AP (p {<=} 0.009) with no statistically significant reduction in image quality (p {<=} 0.483). The dose received by the testes in the PA projection in SIJ imaging is 93.1% lower than the AP projection when not using protection (p {<=} 0.020) and 94.9% lower with protection (p {<=} 0.019). The dose received by the testicles was not changed by the use of a scrotal shield in the AP position (p {<=} 0.559); but was lowered by its use in the PA (p {<=} 0.058). Use of the PA projection in SIJ imaging significantly lowers, the dose received by the testes compared to the AP projection without significant loss of image quality.

Factors influencing bladder stone formation in patients with spinal cord injury.

Science.gov (United States)

Favazza, Terry; Midha, Meena; Martin, Jessicca; Grob, B Mayer

2004-01-01

Bladder stones that form in patients with spinal cord injury (SCI) can cause significant morbidity. This study sought to analyze factors associated with bladder stone formation to determine which patients might be at increased risk to develop bladder stones. A review of 56 SCI patients treated for bladder calculi over a 10-year period at a single institution was performed. These patients were compared with a control population of general SCI patients known to be stone free. The factors compared were patient age, duration of injury, level of injury, completeness of injury, method of bladder management, and the presence of documented urinary tract infections with urease-producing organisms. All patients with stones were male and had a median age of 58.5 years. The median level of injury was C6, the median time since injury was 21 years, 66% had complete injuries, 68% managed their bladders with indwelling catheters or suprapubic tubes, and 83% had a history of infections with urease-producing organisms. When compared with the control group, patients forming bladder stones were older (P = 0.03), were more likely to have indwelling catheters (P < 0.0001), had a history of infections with urease-producing organisms (P = 0.04), and had complete injuries (P = 0.018). This information can be used to identify patients who have an increased risk of bladder stones and measures can be taken to reduce their incidence and morbidity.

Synthesis, biological evaluation and molecular docking studies of ...

African Journals Online (AJOL)

crystal structure of urease (Protein Data Bank ID: 5FSE) as a model enzyme. Furthermore ..... used in the electrostatic, bonding and energy calculations. ... different binding conformations of ligand with receptor ..... Reduced surface: an efficient ...

PA positioning significantly reduces testicular dose during sacroiliac joint radiography

International Nuclear Information System (INIS)

Mekis, Nejc; Mc Entee, Mark F.; Stegnar, Peter

2010-01-01

Radiation dose to the testes in the antero-posterior (AP) and postero-anterior (PA) projection of the sacroiliac joint (SIJ) was measured with and without a scrotal shield. Entrance surface dose, the dose received by the testicles and the dose area product (DAP) was used. DAP measurements revealed the dose received by the phantom in the PA position is 12.6% lower than the AP (p ≤ 0.009) with no statistically significant reduction in image quality (p ≤ 0.483). The dose received by the testes in the PA projection in SIJ imaging is 93.1% lower than the AP projection when not using protection (p ≤ 0.020) and 94.9% lower with protection (p ≤ 0.019). The dose received by the testicles was not changed by the use of a scrotal shield in the AP position (p ≤ 0.559); but was lowered by its use in the PA (p ≤ 0.058). Use of the PA projection in SIJ imaging significantly lowers, the dose received by the testes compared to the AP projection without significant loss of image quality.

The role of nickel in urea assimilation by algae.

Science.gov (United States)

Rees, T A; Bekheet, I A

1982-12-01

Nickel is required for urease synthesis by Phaeodactylum tricornutum and Tetraselmis subcordiformis and for growth on urea by Phaeodactylum. There is no requirement for nickel for urea amidolyase synthesis by Chlorella fusca var. vacuolata. Neither copper nor palladium can substitute for nickel but cobalt partially restored urease activity in Phaeodactylum. The addition of nickel to nickel-deficient cultures of Phaeodactylum or Tetraselmis resulted in a rapid increase of urease activity to 7-30 times the normal level; this increase was not inhibited by cycloheximide. It is concluded that nickel-deficient cells over-produce a non-functional urease protein and that either nickel or the functional urease enzyme participates in the regulation of the production of urease protein.

Soil Enzyme Activities in Pinus tabuliformis (Carriére) Plantations in Northern China

OpenAIRE

Weiwei Wang; Deborah Page-Dumroese; Ruiheng Lv; Chen Xiao; Guolei Li; Yong Liu

2016-01-01

Changes in forest stand structure may alter the activity of invertase, urease, catalase and phenol oxidase after thinning Pinus tabuliformis (Carriére) plantations in Yanqing County of Beijing, China. We examined changes in these soil enzymes as influenced by time since thinning (24, 32, and 40 years since thinning) for 3 seasons (spring, summer and autumn) following harvesting at two depths in the mineral soil (0–10 cm and 10–20 cm). Invertase and urease increased significantly with time sin...

Modest hypoxia significantly reduces triglyceride content and lipid droplet size in 3T3-L1 adipocytes

Energy Technology Data Exchange (ETDEWEB)

Hashimoto, Takeshi, E-mail: thashimo@fc.ritsumei.ac.jp [Faculty of Sport and Health Science, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga 525-8577 (Japan); Yokokawa, Takumi; Endo, Yuriko [Faculty of Sport and Health Science, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga 525-8577 (Japan); Iwanaka, Nobumasa [Ritsumeikan Global Innovation Research Organization, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga 525-8577 (Japan); Higashida, Kazuhiko [Faculty of Sport and Health Science, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga 525-8577 (Japan); Faculty of Sport Science, Waseda University, 2-579-15 Mikajima, Tokorozawa, Saitama 359-1192 (Japan); Taguchi, Sadayoshi [Faculty of Sport and Health Science, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga 525-8577 (Japan)

2013-10-11

Highlights: •Long-term hypoxia decreased the size of LDs and lipid storage in 3T3-L1 adipocytes. •Long-term hypoxia increased basal lipolysis in 3T3-L1 adipocytes. •Hypoxia decreased lipid-associated proteins in 3T3-L1 adipocytes. •Hypoxia decreased basal glucose uptake and lipogenic proteins in 3T3-L1 adipocytes. •Hypoxia-mediated lipogenesis may be an attractive therapeutic target against obesity. -- Abstract: Background: A previous study has demonstrated that endurance training under hypoxia results in a greater reduction in body fat mass compared to exercise under normoxia. However, the cellular and molecular mechanisms that underlie this hypoxia-mediated reduction in fat mass remain uncertain. Here, we examine the effects of modest hypoxia on adipocyte function. Methods: Differentiated 3T3-L1 adipocytes were incubated at 5% O{sub 2} for 1 week (long-term hypoxia, HL) or one day (short-term hypoxia, HS) and compared with a normoxia control (NC). Results: HL, but not HS, resulted in a significant reduction in lipid droplet size and triglyceride content (by 50%) compared to NC (p < 0.01). As estimated by glycerol release, isoproterenol-induced lipolysis was significantly lowered by hypoxia, whereas the release of free fatty acids under the basal condition was prominently enhanced with HL compared to NC or HS (p < 0.01). Lipolysis-associated proteins, such as perilipin 1 and hormone-sensitive lipase, were unchanged, whereas adipose triglyceride lipase and its activator protein CGI-58 were decreased with HL in comparison to NC. Interestingly, such lipogenic proteins as fatty acid synthase, lipin-1, and peroxisome proliferator-activated receptor gamma were decreased. Furthermore, the uptake of glucose, the major precursor of 3-glycerol phosphate for triglyceride synthesis, was significantly reduced in HL compared to NC or HS (p < 0.01). Conclusion: We conclude that hypoxia has a direct impact on reducing the triglyceride content and lipid droplet size via

Modest hypoxia significantly reduces triglyceride content and lipid droplet size in 3T3-L1 adipocytes

International Nuclear Information System (INIS)

Hashimoto, Takeshi; Yokokawa, Takumi; Endo, Yuriko; Iwanaka, Nobumasa; Higashida, Kazuhiko; Taguchi, Sadayoshi

2013-01-01

Highlights: •Long-term hypoxia decreased the size of LDs and lipid storage in 3T3-L1 adipocytes. •Long-term hypoxia increased basal lipolysis in 3T3-L1 adipocytes. •Hypoxia decreased lipid-associated proteins in 3T3-L1 adipocytes. •Hypoxia decreased basal glucose uptake and lipogenic proteins in 3T3-L1 adipocytes. •Hypoxia-mediated lipogenesis may be an attractive therapeutic target against obesity. -- Abstract: Background: A previous study has demonstrated that endurance training under hypoxia results in a greater reduction in body fat mass compared to exercise under normoxia. However, the cellular and molecular mechanisms that underlie this hypoxia-mediated reduction in fat mass remain uncertain. Here, we examine the effects of modest hypoxia on adipocyte function. Methods: Differentiated 3T3-L1 adipocytes were incubated at 5% O 2 for 1 week (long-term hypoxia, HL) or one day (short-term hypoxia, HS) and compared with a normoxia control (NC). Results: HL, but not HS, resulted in a significant reduction in lipid droplet size and triglyceride content (by 50%) compared to NC (p < 0.01). As estimated by glycerol release, isoproterenol-induced lipolysis was significantly lowered by hypoxia, whereas the release of free fatty acids under the basal condition was prominently enhanced with HL compared to NC or HS (p < 0.01). Lipolysis-associated proteins, such as perilipin 1 and hormone-sensitive lipase, were unchanged, whereas adipose triglyceride lipase and its activator protein CGI-58 were decreased with HL in comparison to NC. Interestingly, such lipogenic proteins as fatty acid synthase, lipin-1, and peroxisome proliferator-activated receptor gamma were decreased. Furthermore, the uptake of glucose, the major precursor of 3-glycerol phosphate for triglyceride synthesis, was significantly reduced in HL compared to NC or HS (p < 0.01). Conclusion: We conclude that hypoxia has a direct impact on reducing the triglyceride content and lipid droplet size via

Smoking cessation programmes in radon affected areas: can they make a significant contribution to reducing radon-induced lung cancers?

International Nuclear Information System (INIS)

Denman, A.R.; Groves-Kirkby, C.J.; Timson, K.; Shield, G.; Rogers, S.; Phillips, P.S.

2008-01-01

Domestic radon levels in parts of the UK are sufficiently high to increase the risk of lung cancer in the occupants. Public health campaigns in Northamptonshire, a designated radon affected area with 6.3% of homes having average radon levels over the UK action level of 200 Bq m -3 , have encouraged householders to test for radon and then to carry out remediation in their homes, but have been only partially successful. Only 40% of Northamptonshire houses have been tested, and only 15% of householders finding raised levels proceed to remediate. Of those who did remediate, only 9% smoked, compared to a countywide average of 28.8%. This is unfortunate, since radon and smoking combine to place the individual at higher risk by a factor of around 4, and suggests that current strategies to reduce domestic radon exposure are not reaching those most at risk. During 2004-5, the NHS Stop Smoking Services in Northamptonshire assisted 2,808 smokers to quit to the 4-week stage, with some 30% of 4-week quitters remaining quitters at 1 year. We consider whether smoking cessation campaigns make significant contributions to radon risk reduction on their own, by assessing individual occupants' risk of developing lung cancer from knowledge of their age, gender, and smoking habits, together with he radon level in their house. The results demonstrate that smoking cessation programmes have significant added value in radon affected areas, and contribute a greater health benefit than reducing radon levels in the smokers' homes, whilst they remain smokers. Additionally, results are presented from a questionnaire-based survey of quitters, addressing their reasons for seeking help in quitting smoking, and whether knowledge of radon risks influenced this decision. The impact of these findings on future public health campaigns to reduce the impact of radon and smoking are discussed. (author)

The Pathogenic Potential of Proteus mirabilis Is Enhanced by Other Uropathogens during Polymicrobial Urinary Tract Infection.

Science.gov (United States)

Armbruster, Chelsie E; Smith, Sara N; Johnson, Alexandra O; DeOrnellas, Valerie; Eaton, Kathryn A; Yep, Alejandra; Mody, Lona; Wu, Weisheng; Mobley, Harry L T

2017-02-01

Urinary catheter use is prevalent in health care settings, and polymicrobial colonization by urease-positive organisms, such as Proteus mirabilis and Providencia stuartii, commonly occurs with long-term catheterization. We previously demonstrated that coinfection with P. mirabilis and P. stuartii increased overall urease activity in vitro and disease severity in a model of urinary tract infection (UTI). In this study, we expanded these findings to a murine model of catheter-associated UTI (CAUTI), delineated the contribution of enhanced urease activity to coinfection pathogenesis, and screened for enhanced urease activity with other common CAUTI pathogens. In the UTI model, mice coinfected with the two species exhibited higher urine pH values, urolithiasis, bacteremia, and more pronounced tissue damage and inflammation compared to the findings for mice infected with a single species, despite having a similar bacterial burden within the urinary tract. The presence of P. stuartii, regardless of urease production by this organism, was sufficient to enhance P. mirabilis urease activity and increase disease severity, and enhanced urease activity was the predominant factor driving tissue damage and the dissemination of both organisms to the bloodstream during coinfection. These findings were largely recapitulated in the CAUTI model. Other uropathogens also enhanced P. mirabilis urease activity in vitro, including recent clinical isolates of Escherichia coli, Enterococcus faecalis, Klebsiella pneumoniae, and Pseudomonas aeruginosa We therefore conclude that the underlying mechanism of enhanced urease activity may represent a widespread target for limiting the detrimental consequences of polymicrobial catheter colonization, particularly by P. mirabilis and other urease-positive bacteria. Copyright © 2017 American Society for Microbiology.

Enzyme activity and kinetics in substrate-amended river sediments

Energy Technology Data Exchange (ETDEWEB)

Duddridge, J E; Wainwright, M

1982-01-01

In determining the effects of heavy metals in microbial activity and litter degradation in river sediments, one approach is to determine the effects of these pollutants on sediment enzyme activity and synthesis. Methods to assay amylase, cellulase and urease activity in diverse river sediments are reported. Enzyme activity was low in non-amended sediments, but increased markedly when the appropriate substrate was added, paralleling both athropogenic and natural amendment. Linear relationships between enzyme activity, length of incubation, sample size and substrate concentration were established. Sediment enzyme activity generally obeyed Michaelis-Menton kinetics, but of the three enzymes, urease gave least significant correlation coefficients when the data for substrate concentration versus activity was applied to the Eadie-Hofstee transformation of the Michaelis-Menten equation. K/sub m/ and V/sub max/ for amylase, cellulase and urease in sediments are reported. (JMT)

[Soil soluble organic matter, microbial biomass, and enzyme activities in forest plantations in degraded red soil region of Jiangxi Province, China].

Science.gov (United States)

Jiang, Yu-mei; Chen, Cheng-long; Xu, Zhi-hong; Liu, Yuan-qiu; Ouyang, Jing; Wang, Fang

2010-09-01

Taking the adjacent 18-year-old pure Pinus massoniana pure forest (I), P. massoniana, Liquidamber fomosana, and Schima superba mixed forest (II), S. superba pure forest (III), L. fomosana (IV) pure forest, and natural restoration fallow land (CK) in Taihe County of Jiangxi Province as test sites, a comparative study was made on their soil soluble organic carbon (SOC) and nitrogen (SON), soil microbial biomass C (MBC) and N (MBN), and soil urease and asparaginase activities. In 0-10 cm soil layer, the pool sizes of SOC, SON, MBC, and MBN at test sites ranged in 354-1007 mg x kg(-1), 24-73 mg x kg(-1), 203-488 mg x kg(-1), and 24-65 mg x kg(-1), and the soil urease and asparaginase activities were 95-133 mg x kg(-1) x d(-1) and 58-113 mg x kg(-1) x d(-1), respectively. There were significant differences in the pool sizes of SOC, SON, MBC, and MBN and the asparaginase activity among the test sites, but no significant difference was observed in the urease activity. The pool sizes of SOC and SON were in the order of IV > CK > III > I > II, those of MBC and MBN were in the order of CK > IV > III > I > II, and asparaginase activity followed the order of IV > CK > III > II > I. With the increase of soil depth, the pool sizes of SOC, SON, MBC, and MBN and the activities of soil asparaginase and urease decreased. In 0-20 cm soil layer, the SOC, SON, MBC, MBN, total C, and total N were highly correlated with each other, soil asparaginase activity was highly correlated with SOC, SON, TSN, total C, total N, MBC, and MBN, and soil urease activity was highly correlated with SON, TSN, total C, MBC and MBN.

Influence of exogenous lead pollution on enzyme activities and organic matter degradation in the surface of river sediment.

Science.gov (United States)

Huang, Danlian; Xu, Juanjuan; Zeng, Guangming; Lai, Cui; Yuan, Xingzhong; Luo, Xiangying; Wang, Cong; Xu, Piao; Huang, Chao

2015-08-01

As lead is one of the most hazardous heavy metals in river ecosystem, the influence of exogenous lead pollution on enzyme activities and organic matter degradation in the surface of river sediment with high moisture content were studied at laboratory scale. The dynamic changes of urease, catalase, protease activities, organic matter content, and exchangeable or ethylenediaminetetraacetic acid (EDTA)-extractable Pb concentration in sediment were monitored during different levels of exogenous lead infiltrating into sediment. At the early stage of incubation, the activities of catalase and protease were inhibited, whereas the urease activities were enhanced with different levels of exogenous lead. Organic matter content in polluted sediment with exogenous lead was lower than control and correlated with enzyme activities. In addition, the effects of lead on the three enzyme activities were strongly time-dependent and catalase activities showed lower significant difference (P < 0.05) than urease and protease. Correlations between catalase activities and EDTA-extractable Pb in the experiment were significantly negative. The present findings will improve the understandings about the ecotoxicological mechanisms in sediment.

Using lytic bacteriophages to eliminate or significantly reduce contamination of food by foodborne bacterial pathogens.

Science.gov (United States)

Sulakvelidze, Alexander

2013-10-01

Bacteriophages (also called 'phages') are viruses that kill bacteria. They are arguably the oldest (3 billion years old, by some estimates) and most ubiquitous (total number estimated to be 10(30) -10(32) ) known organisms on Earth. Phages play a key role in maintaining microbial balance in every ecosystem where bacteria exist, and they are part of the normal microflora of all fresh, unprocessed foods. Interest in various practical applications of bacteriophages has been gaining momentum recently, with perhaps the most attention focused on using them to improve food safety. That approach, called 'phage biocontrol', typically includes three main types of applications: (i) using phages to treat domesticated livestock in order to reduce their intestinal colonization with, and shedding of, specific bacterial pathogens; (ii) treatments for decontaminating inanimate surfaces in food-processing facilities and other food establishments, so that foods processed on those surfaces are not cross-contaminated with the targeted pathogens; and (iii) post-harvest treatments involving direct applications of phages onto the harvested foods. This mini-review primarily focuses on the last type of intervention, which has been gaining the most momentum recently. Indeed, the results of recent studies dealing with improving food safety, and several recent regulatory approvals of various commercial phage preparations developed for post-harvest food safety applications, strongly support the idea that lytic phages may provide a safe, environmentally-friendly, and effective approach for significantly reducing contamination of various foods with foodborne bacterial pathogens. However, some important technical and nontechnical problems may need to be addressed before phage biocontrol protocols can become an integral part of routine food safety intervention strategies implemented by food industries in the USA. © 2013 Society of Chemical Industry.

Influence of mammal fossorial activity on the soil fermentative activity in conditions of metallurgical production

Directory of Open Access Journals (Sweden)

S. M. Kirienko

2010-09-01

Full Text Available Effect of mammal fossorial activity as an ecological factor of the soil genesis intensification is studied. Enzymatic activity of soil as its ability to demonstrate a catalytic effect for various compounds transformation is examined. Variability of soil urease activity in technogenic conditions with the participation of animals is shown. The positive influence of animals’ activity on the catalitic ability of the investigated soils was determined. The statistically significant characteristics which have an influence on the urease activity in soil are found out.

From meatless Mondays to meatless Sundays: motivations for meat reduction among vegetarians and semi-vegetarians who mildly or significantly reduce their meat intake.

Science.gov (United States)

De Backer, Charlotte J S; Hudders, Liselot

2014-01-01

This study explores vegetarians' and semi-vegetarians' motives for reducing their meat intake. Participants are categorized as vegetarians (remove all meat from their diet); semi-vegetarians (significantly reduce meat intake: at least three days a week); or light semi-vegetarians (mildly reduce meat intake: once or twice a week). Most differences appear between vegetarians and both groups of semi-vegetarians. Animal-rights and ecological concerns, together with taste preferences, predict vegetarianism, while an increase in health motives increases the odds of being semi-vegetarian. Even within each group, subgroups with different motives appear, and it is recommended that future researchers pay more attention to these differences.

GenBank blastx search result: AK104368 [KOME

Lifescience Database Archive (English)

Full Text Available ase accessory protein D (ureD), urease structural subunit A (ureA), urease accessory protein J (ureJ), ureas...e structural subunits B (ureB) and C (ureC), urease accessory proteins EF (ureEF) and G (ureG) genes, complete cds.|BCT BCT 9e-57 +1 ... ...AK104368 001-035-E04 AF000579.1 Bordetella bronchiseptica LysR transcriptional activator homolog (bbuR), ure

Biological mechanisms associated with triazophos (TAP) removal by horizontal subsurface flow constructed wetlands (HSFCW)

International Nuclear Information System (INIS)

Wu, Juan; Feng, Yuqin; Dai, Yanran; Cui, Naxin; Anderson, Bruce; Cheng, Shuiping

2016-01-01

Triazophos (TAP) is a widely used pesticide that is easily accumulated in the environment due to its relatively high stability: this accumulation from agricultural runoff results in potential hazards to aquatic ecosystems. Constructed wetlands are generally considered to be an effective technology for treating TAP polluted surface water. However, knowledge about the biological mechanisms of TAP removal is still lacking. This study investigates the responses of a wetland plant (Canna indica), substrate enzymes and microbial communities in bench-scale horizontal subsurface-flow constructed wetlands (HSCWs) loaded with different TAP concentrations (0, 0.1, 0.5 and 5 mg·L"−"1). The results indicate that TAP stimulated the activities of superoxide dismutase (SOD) and peroxidase (POD) in the roots of C. indica. The highest TAP concentrations significantly inhibited photosynthetic activities, as shown by a reduced effective quantum yield of PS II (Φ_P_S_I_I) and lower electron transport rates (ETR). However, interestingly, the lower TAP loadings exhibited some favorable effects on these two variables, suggesting that C. indica is a suitable species for use in wetlands designed for treatment of low TAP concentrations. Urease and alkaline phosphatase (ALP) in the wetland substrate were activated by TAP. Two-way ANOVA demonstrated that urease activity was influenced by both the TAP concentrations and season, while acidphosphatase (ACP) only responded to seasonal variations. Analysis of high throughput sequencing of 16S rRNA revealed seasonal variations in the microbial community structure of the wetland substrate at the phylum and family levels. In addition, urease activity had a greater correlation with the relative abundance of some functional microbial groups, such as the Bacillaceae family, and the ALP and ACP may be influenced by the plant more than substrate microbial communities. - Highlights: • Physiological responses of the wetland plant to triazophos loads

Biological mechanisms associated with triazophos (TAP) removal by horizontal subsurface flow constructed wetlands (HSFCW)

Energy Technology Data Exchange (ETDEWEB)

Wu, Juan; Feng, Yuqin; Dai, Yanran; Cui, Naxin [State Key Laboratory of Pollution Control and ResourceReuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China); Anderson, Bruce [Department of Civil Engineering, Queen' s University, Kingston K7L3N6 (Canada); Cheng, Shuiping, E-mail: shpcheng@tongji.edu.cn [State Key Laboratory of Pollution Control and ResourceReuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China)

2016-05-15

Triazophos (TAP) is a widely used pesticide that is easily accumulated in the environment due to its relatively high stability: this accumulation from agricultural runoff results in potential hazards to aquatic ecosystems. Constructed wetlands are generally considered to be an effective technology for treating TAP polluted surface water. However, knowledge about the biological mechanisms of TAP removal is still lacking. This study investigates the responses of a wetland plant (Canna indica), substrate enzymes and microbial communities in bench-scale horizontal subsurface-flow constructed wetlands (HSCWs) loaded with different TAP concentrations (0, 0.1, 0.5 and 5 mg·L{sup −1}). The results indicate that TAP stimulated the activities of superoxide dismutase (SOD) and peroxidase (POD) in the roots of C. indica. The highest TAP concentrations significantly inhibited photosynthetic activities, as shown by a reduced effective quantum yield of PS II (Φ{sub PSII}) and lower electron transport rates (ETR). However, interestingly, the lower TAP loadings exhibited some favorable effects on these two variables, suggesting that C. indica is a suitable species for use in wetlands designed for treatment of low TAP concentrations. Urease and alkaline phosphatase (ALP) in the wetland substrate were activated by TAP. Two-way ANOVA demonstrated that urease activity was influenced by both the TAP concentrations and season, while acidphosphatase (ACP) only responded to seasonal variations. Analysis of high throughput sequencing of 16S rRNA revealed seasonal variations in the microbial community structure of the wetland substrate at the phylum and family levels. In addition, urease activity had a greater correlation with the relative abundance of some functional microbial groups, such as the Bacillaceae family, and the ALP and ACP may be influenced by the plant more than substrate microbial communities. - Highlights: • Physiological responses of the wetland plant to triazophos

Effect of antibiotics, prebiotics and probiotics in treatment for hepatic encephalopathy.

NARCIS (Netherlands)

Bongaerts, G.P.A.; Severijnen, R.S.V.M.; Timmerman, H.

2005-01-01

In order to reduce ammonia production by urease-positive bacteria Solga recently hypothesised (S.F. Solga, Probiotics can treat hepatic encephalopathy, Medical Hypotheses 2003; 61: 307-13), that probiotics are new therapeutics for hepatic encephalopathy (HE), and that they may replace antibiotics

Sol-Gel Derived Adsorbents with Enzymatic and Complexonate Functions for Complex Water Remediation

Directory of Open Access Journals (Sweden)

Roman P. Pogorilyi

2017-09-01

Full Text Available Sol-gel technology is a versatile tool for preparation of complex silica-based materials with targeting functions for use as adsorbents in water purification. Most efficient removal of organic pollutants is achieved by using enzymatic reagents grafted on nano-carriers. However, enzymes are easily deactivated in the presence of heavy metal cations. In this work, we avoided inactivation of immobilized urease by Cu (II and Cd (II ions using magnetic nanoparticles provided with additional complexonate (diethylene triamine pentaacetic acid or DTPA functions. Obtained nanomaterials were characterized by Fourier transform infrared spectroscopy (FTIR, thermogravimetric analysis (TGA, and scanning electron microscopy (SEM. According to TGA, the obtained Fe3O4/SiO2-NH2-DTPA nanoadsorbents contained up to 0.401 mmol/g of DTPA groups. In the concentration range Ceq = 0–50 mmol/L, maximum adsorption capacities towards Cu (II and Cd (II ions were 1.1 mmol/g and 1.7 mmol/g, respectively. Langmuir adsorption model fits experimental data in concentration range Ceq = 0–10 mmol/L. The adsorption mechanisms have been evaluated for both of cations. Crosslinking of 5 wt % of immobilized urease with glutaraldehyde prevented the loss of the enzyme in repeated use of the adsorbent and improved the stability of the enzymatic function leading to unchanged activity in at least 18 cycles. Crosslinking of 10 wt % urease on the surface of the particles allowed a decrease in urea concentration in 20 mmol/L model solutions to 2 mmol/L in up to 10 consequent decomposition cycles. Due to the presence of DTPA groups, Cu2+ ions in concentration 1 µmol/L did not significantly affect the urease activity. Obtained magnetic Fe3O4/SiO2-NH2-DTPA-Urease nanocomposite sorbents revealed a high potential for urease decomposition, even in presence of heavy metal ions.

Walking with a four wheeled walker (rollator) significantly reduces EMG lower-limb muscle activity in healthy subjects.

Science.gov (United States)

Suica, Zorica; Romkes, Jacqueline; Tal, Amir; Maguire, Clare

2016-01-01

To investigate the immediate effect of four-wheeled- walker(rollator)walking on lower-limb muscle activity and trunk-sway in healthy subjects. In this cross-sectional design electromyographic (EMG) data was collected in six lower-limb muscle groups and trunk-sway was measured as peak-to-peak angular displacement of the centre-of-mass (level L2/3) in the sagittal and frontal-planes using the SwayStar balance system. 19 subjects walked at self-selected speed firstly without a rollator then in randomised order 1. with rollator 2. with rollator with increased weight-bearing. Rollator-walking caused statistically significant reductions in EMG activity in lower-limb muscle groups and effect-sizes were medium to large. Increased weight-bearing increased the effect. Trunk-sway in the sagittal and frontal-planes showed no statistically significant difference between conditions. Rollator-walking reduces lower-limb muscle activity but trunk-sway remains unchanged as stability is likely gained through forces generated by the upper-limbs. Short-term stability is gained but the long-term effect is unclear and requires investigation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Potent corticosteroid cream (mometasone furoate) significantly reduces acute radiation dermatitis: results from a double-blind, randomized study

International Nuclear Information System (INIS)

Bostroem, Aasa; Lindman, Henrik; Swartling, Carl; Berne, Berit; Bergh, Jonas

2001-01-01

Purpose: Radiation-induced dermatitis is a very common side effect of radiation therapy, and may necessitate interruption of the therapy. There is a substantial lack of evidence-based treatments for this condition. The aim of this study was to investigate the effect of mometasone furoate cream (MMF) on radiation dermatitis in a prospective, double-blind, randomized study. Material and methods: The study comprised 49 patients with node-negative breast cancer. They were operated on with sector resection and scheduled for postoperative radiotherapy using photons with identical radiation qualities and dosage to the breast parenchyma. The patients were randomized to receive either MMF or emollient cream. The cream was applied on the irradiated skin twice a week from the start of radiotherapy until the 12th fraction (24 Gy) and thereafter once daily until 3 weeks after completion of radiation. Both groups additionally received non-blinded emollient cream daily. The intensity of the acute radiation dermatitis was evaluated on a weekly basis regarding erythema and pigmentation, using a reflectance spectrophotometer together with visual scoring of the skin reactions. Results: MMF in combination with emollient cream treatment significantly decreased acute radiation dermatitis (P=0.0033) compared with emollient cream alone. There was no significant difference in pigmentation between the two groups. Conclusions: Adding MMF, a potent topical corticosteroid, to an emollient cream is statistically significantly more effective than emollient cream alone in reducing acute radiation dermatitis

Utilization of C-14 settled urease for diagnosing Campylobacter Pylori in the stomach. Utilizacao de ureia marcada com carbono quatorze para diagnostico da presenca do Campylobacter Pylori no estomago

Energy Technology Data Exchange (ETDEWEB)

Chausson, Y; Coelho, L G.V. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN), Belo Horizonte, MG (Brazil)

1990-01-01

A new method for diagnosing the Campylobacter Pylori in the stomach is described, using C-14 settled urease. Campylobacter Pylori is now being considered the most probable causative agent of antral chronic gastritis, pepitic ulcer and non-ulcerous dyspepsia. The technique is based on ingestion of the tracer, its recovery by exhalation in etanol hyamine solution, followed by counting and dates evaluation. The test was applied to forty two voluntary male and female patients, after their written acquiescence. Their ages varied from 19 to 62 years old. Thirty of the results were positive and twelve negative. All of them were comproved by microbiological (cultura) and hystologycal studies of gastric biopsy gotten by gastroscopy. They were performed at the Gastroentherology Departament of the 'Hospital das Clinicas' that belongs to the Federal University of Minas Gerais. Repetitivity of the breath test was confirmed by repetition of the results in five positive patients and five negative ones. (author).

Environmental program with operational cases to reduce risk to the marine environment significantly

International Nuclear Information System (INIS)

Cline, J.T.; Forde, R.

1991-01-01

In this paper Amoco Norway Oil Company's environmental program is detailed, followed by example operational programs and achievements aimed to minimize environmental risks to the marine environment at Valhall platform. With a corporate goal to be a leader in protecting the environment, the appropriate strategies and policies that form the basis of the environmental management system are incorporated in the quality assurance programs. Also, included in the program are necessary organizational structures, responsibilities of environmental affairs and line organization personnel, compliance procedures and a waste task force obliged to implement operations improvements. An internal environmental audit system has been initiated, in addition to corporate level audits, which, when communicated to the line organization closes the environmental management loop through experience feed back. Environmental projects underway are significantly decreasing the extent and/or risk of pollution from offshore activities. The cradle to grave responsibility is assumed with waste separated offshore and onshore followed by disposal in audited sites. A $5 MM program is underway to control produced oily solids and reduce oil in produced water aiming to less than 20 ppm. When oil-based mud is used in deeper hole sections, drill solids disposed at sea average less than 60 g oil/kg dry cuttings using appropriate shaker screens, and a washing/centrifuge system to remove fines. Certain oily liquid wastes are being injected down hole whereas previously they were burned using a mud burner. Finally, a program is underway with a goal to eliminate sea discharge of oil on cuttings through injection disposal of oily wastes, drilling with alternative muds such as a cationic water base mud, and/or proper onshore disposal of oily wastes

GenBank blastx search result: AK104368 [KOME

Lifescience Database Archive (English)

Full Text Available AK104368 001-035-E04 L03308.1 E.coli urease gene cluster: urease accessory protein F (UreF), 3' end cds; ure...ase accessory protein G (UreG) gene, complete cds.|BCT BCT 2e-56 +1 ...

Speciation and Biofilm Production of Coagulase Negative Staphylococcal Isolates from Clinically Significant Specimens and their Antibiogram

Directory of Open Access Journals (Sweden)

S. S. Vijayasri Badampudi

2016-04-01

Full Text Available Background: Coagulase Negative Staphylococci (CONS are increasingly recognized as significant nosocomial pathogens. Their ability of biofilm formation and multiple drug resistance are causing serious human infections. Aim and Objectives: To isolate, identify, speciate clinically significant CONS from various specimens, to study antibiotic resistance pattern and biofilm production. Material and Methods: Specimens were collected aseptically, processed and identified upto the species level by a simple scheme of tests urease, novobiocin resistance, mannose and mannitol fermentation, ornithine decarboxylase. Antibiotic sensitivity was done with special reference to methicillin resistance. Biofilm formation was detected by Congo Red Agar (CRA method and Tube Method (TM. Results: Study groupOf 100 isolates majority were pus (40, followed by urine (28, blood (16, CSF (5, body fluids (4 and catheter tips and implants (7. The most common species isolated was S. epidermidis (40% followed by S. haemolyticus (26%, S. saprophyticus (15%, S. schleiferi (13%, S. simulans (2%, S. cohnii (2% and S. warneri and S. capitis each 1%. Resistance to penicillin was 91% followed by ampicillin (79%, cotrimoxazole (67%. Methicillin resistance was 72%. Biofilm producers were 69% by CRAmethod and 33% by TM with majority species S. epidermidis (82.5%- CRA and 55%-TM. Biofilm production was significantly associated with MRCONS (p value 0.0036. Control group-Of 30 isolates were S. epidermidis 66.6% followed by S. haemolyticus (16.66%. Biofilm producers were 53.33% by CRA method and 26.65% by TM with majority species S. epidermidis (65%-CRA and 30%-TM.Methicillin resistance was 26.6%. Conclusion: Clinical significance of CONS is increasing day by day, so there is a need for accurate identification to species level and their antibiogram to avoid multidrug resistance. Biofilm producing CONS species pose a risk and CRA method for screening biofilm can be used in all conventional

Short-Term Effect of Vermicompost Application on Biological Properties of an Alkaline Soil with High Lime Content from Mediterranean Region of Turkey

Science.gov (United States)

Uz, Ilker; Tavali, Ismail Emrah

2014-01-01

This study was conducted to investigate direct short-term impact of vermicompost on some soil biological properties by monitoring changes after addition of vermicompost as compared to farmyard manure in an alkaline soil with high lime content from semiarid Mediterranean region of Turkey. For this purpose, mixtures of soil and organic fertilizers in different doses were incubated under greenhouse condition. Soil samples collected in regular intervals were analyzed for biological parameters including dehydrogenase, β-glucosidase, urease, alkaline phosphatase activities, and total number of aerobic mesophilic bacteria. Even though soil dehydrogenase activity appeared to be dose-independent based on overall evaluation, organic amendments were found to elevate dehydrogenase activity when sampling periods are evaluated individually. β-glucosidase, urease, alkaline phosphatase activity, and aerobic mesophilic bacterial numbers in vermicompost treatments fluctuated but remained significantly above the control. A slight but statistically significant difference was detected between organic amendments in terms of urease activity. Vermicompost appeared to more significantly increase bacterial number in soil. Clearly, vermicompost has a potential to be used as an alternative to farmyard manure to improve and maintain soil biological activity in alkaline calcareous soils from the Mediterranean region of Turkey. Further studies are needed to assess its full potential for these soils. PMID:25254238

Role of ureolytic activity in Bacillus cereus nitrogen metabolism and acid survival

NARCIS (Netherlands)

Mols, J.M.; Abee, T.

2008-01-01

The presence and activities of urease genes were investigated in 49 clinical, food, and environmental Bacillus cereus isolates. Ten strains were shown to have urease genes, with eight of these strains showing growth on urea as the sole nitrogen source. Two of the urease-positive strains, including

[Effects of long-term fertilization on enzyme activities in black soil of Northeast China].

Science.gov (United States)

Wang, Shu-Qi; Han, Xiao-Zeng; Qiao, Yun-Fa; Wang, Shou-Yu

2008-03-01

In this paper, black soil samples at the depths of 0-20 cm and 20-40 cm were collected from the Hailun Agricultural Ecology Station of Chinese Academy of Sciences to study the effects of long-term fertilization on their urease, invertase, phosphatase and catalase activities and total C and N contents. The results showed that long-term application of chemical fertilizers and organic manure increased the activities of urease, invertase and phosphatase in 0-20 cm and 20-40 cm soil layers in different degree, and the combined application of them increased the activities of the three enzymes significantly, with an increment of 43.6%-113.2%, 25.9%-79.5% and 14.7%-134.4% in 0-20 cm soil layer and 56.1%-127.2%, 14.5%-113.8% and 16.2%-207.2% in 20-40 cm soil layer, respectively. However, long-term application of chemical fertilizers without organic manure had little effects on catalase activity. The activities of urease, invertase and phosphatase decreased with increasing soil depth. Long-term application of N fertilizer increased urease activity, and P fertilization had obvious positive effect on phosphatase activity. Long-term fertilization also had obvious effects on the soil total C and N contents and C/N ratio.

Lipid Replacement Therapy Drink Containing a Glycophospholipid Formulation Rapidly and Significantly Reduces Fatigue While Improving Energy and Mental Clarity

Directory of Open Access Journals (Sweden)

Robert Settineri

2011-08-01

Full Text Available Background: Fatigue is the most common complaint of patients seeking general medical care and is often treated with stimulants. It is also important in various physical activities of relatively healthy men and women, such as sports performance. Recent clinical trials using patients with chronic fatigue have shown the benefit of Lipid Replacement Therapy in restoring mitochondrial electron transport function and reducing moderate to severe chronic fatigue. Methods: Lipid Replacement Therapy was administered for the first time as an all-natural functional food drink (60 ml containing polyunsaturated glycophospholipids but devoid of stimulants or herbs to reduce fatigue. This preliminary study used the Piper Fatigue Survey instrument as well as a supplemental questionnaire to assess the effects of the glycophospholipid drink on fatigue and the acceptability of the test drink in adult men and women. A volunteer group of 29 subjects of mean age 56.2±4.5 years with various fatigue levels were randomly recruited in a clinical health fair setting to participate in an afternoon open label trial on the effects of the test drink. Results: Using the Piper Fatigue instrument overall fatigue among participants was reduced within the 3-hour seminar by a mean of 39.6% (p<0.0001. All of the subcategories of fatigue showed significant reductions. Some subjects responded within 15 minutes, and the majority responded within one hour with increased energy and activity and perceived improvements in cognitive function, mental clarity and focus. The test drink was determined to be quite acceptable in terms of taste and appearance. There were no adverse events from the energy drink during the study.Functional Foods in Health and Disease 2011; 8:245-254Conclusions: The Lipid Replacement Therapy functional food drink appeared to be a safe, acceptable and potentially useful new method to reduce fatigue, sustain energy and improve perceptions of mental function.

Scenario analysis of fertilizer management practices for N2O mitigation from corn systems in Canada.

Science.gov (United States)

Abalos, Diego; Smith, Ward N; Grant, Brian B; Drury, Craig F; MacKell, Sarah; Wagner-Riddle, Claudia

2016-12-15

Effective management of nitrogen (N) fertilizer application by farmers provides great potential for reducing emissions of the potent greenhouse gas nitrous oxide (N 2 O). However, such potential is rarely achieved because our understanding of what practices (or combination of practices) lead to N 2 O reductions without compromising crop yields remains far from complete. Using scenario analysis with the process-based model DNDC, this study explored the effects of nine fertilizer practices on N 2 O emissions and crop yields from two corn production systems in Canada. The scenarios differed in: timing of fertilizer application, fertilizer rate, number of applications, fertilizer type, method of application and use of nitrification/urease inhibitors. Statistical analysis showed that during the initial calibration and validation stages the simulated results had no significant total error or bias compared to measured values, yet grain yield estimations warrant further model improvement. Sidedress fertilizer applications reduced yield-scaled N 2 O emissions by c. 60% compared to fall fertilization. Nitrification inhibitors further reduced yield-scaled N 2 O emissions by c. 10%; urease inhibitors had no effect on either N 2 O emissions or crop productivity. The combined adoption of split fertilizer application with inhibitors at a rate 10% lower than the conventional application rate (i.e. 150kgNha -1 ) was successful, but the benefits were lower than those achieved with single fertilization at sidedress. Our study provides a comprehensive assessment of fertilizer management practices that enables policy development regarding N 2 O mitigation from agricultural soils in Canada. Copyright © 2016 Elsevier B.V. All rights reserved.

Soil nitrate reducing processes - drivers, mechanisms for spatial variation, and significance for nitrous oxide production.

Science.gov (United States)

Giles, Madeline; Morley, Nicholas; Baggs, Elizabeth M; Daniell, Tim J

2012-01-01

The microbial processes of denitrification and dissimilatory nitrate reduction to ammonium (DNRA) are two important nitrate reducing mechanisms in soil, which are responsible for the loss of nitrate ([Formula: see text]) and production of the potent greenhouse gas, nitrous oxide (N(2)O). A number of factors are known to control these processes, including O(2) concentrations and moisture content, N, C, pH, and the size and community structure of nitrate reducing organisms responsible for the processes. There is an increasing understanding associated with many of these controls on flux through the nitrogen cycle in soil systems. However, there remains uncertainty about how the nitrate reducing communities are linked to environmental variables and the flux of products from these processes. The high spatial variability of environmental controls and microbial communities across small sub centimeter areas of soil may prove to be critical in determining why an understanding of the links between biotic and abiotic controls has proved elusive. This spatial effect is often overlooked as a driver of nitrate reducing processes. An increased knowledge of the effects of spatial heterogeneity in soil on nitrate reduction processes will be fundamental in understanding the drivers, location, and potential for N(2)O production from soils.

Significantly reduced hypoxemic events in morbidly obese patients undergoing gastrointestinal endoscopy: Predictors and practice effect

Directory of Open Access Journals (Sweden)

Basavana Gouda Goudra

2014-01-01

Full Text Available Background: Providing anesthesia for gastrointestinal (GI endoscopy procedures in morbidly obese patients is a challenge for a variety of reasons. The negative impact of obesity on the respiratory system combined with a need to share the upper airway and necessity to preserve the spontaneous ventilation, together add to difficulties. Materials and Methods: This retrospective cohort study included patients with a body mass index (BMI >40 kg/m 2 that underwent out-patient GI endoscopy between September 2010 and February 2011. Patient data was analyzed for procedure, airway management technique as well as hypoxemic and cardiovascular events. Results: A total of 119 patients met the inclusion criteria. Our innovative airway management technique resulted in a lower rate of intraoperative hypoxemic events compared with any published data available. Frequency of desaturation episodes showed statistically significant relation to previous history of obstructive sleep apnea (OSA. These desaturation episodes were found to be statistically independent of increasing BMI of patients. Conclusion: Pre-operative history of OSA irrespective of associated BMI values can be potentially used as a predictor of intra-procedural desaturation. With suitable modification of anesthesia technique, it is possible to reduce the incidence of adverse respiratory events in morbidly obese patients undergoing GI endoscopy procedures, thereby avoiding the need for endotracheal intubation.

Significantly reduced hypoxemic events in morbidly obese patients undergoing gastrointestinal endoscopy: Predictors and practice effect.

Science.gov (United States)

Goudra, Basavana Gouda; Singh, Preet Mohinder; Penugonda, Lakshmi C; Speck, Rebecca M; Sinha, Ashish C

2014-01-01

Providing anesthesia for gastrointestinal (GI) endoscopy procedures in morbidly obese patients is a challenge for a variety of reasons. The negative impact of obesity on the respiratory system combined with a need to share the upper airway and necessity to preserve the spontaneous ventilation, together add to difficulties. This retrospective cohort study included patients with a body mass index (BMI) >40 kg/m(2) that underwent out-patient GI endoscopy between September 2010 and February 2011. Patient data was analyzed for procedure, airway management technique as well as hypoxemic and cardiovascular events. A total of 119 patients met the inclusion criteria. Our innovative airway management technique resulted in a lower rate of intraoperative hypoxemic events compared with any published data available. Frequency of desaturation episodes showed statistically significant relation to previous history of obstructive sleep apnea (OSA). These desaturation episodes were found to be statistically independent of increasing BMI of patients. Pre-operative history of OSA irrespective of associated BMI values can be potentially used as a predictor of intra-procedural desaturation. With suitable modification of anesthesia technique, it is possible to reduce the incidence of adverse respiratory events in morbidly obese patients undergoing GI endoscopy procedures, thereby avoiding the need for endotracheal intubation.

Dermal application of nitric oxide releasing acidified nitrite-containing liniments significantly reduces blood pressure in humans.

Science.gov (United States)

Opländer, Christian; Volkmar, Christine M; Paunel-Görgülü, Adnana; Fritsch, Thomas; van Faassen, Ernst E; Mürtz, Manfred; Grieb, Gerrit; Bozkurt, Ahmet; Hemmrich, Karsten; Windolf, Joachim; Suschek, Christoph V

2012-02-15

Vascular ischemic diseases, hypertension, and other systemic hemodynamic and vascular disorders may be the result of impaired bioavailability of nitric oxide (NO). NO but also its active derivates like nitrite or nitroso compounds are important effector and signal molecules with vasodilating properties. Our previous findings point to a therapeutical potential of cutaneous administration of NO in the treatment of systemic hemodynamic disorders. Unfortunately, no reliable data are available on the mechanisms, kinetics and biological responses of dermal application of nitric oxide in humans in vivo. The aim of the study was to close this gap and to explore the therapeutical potential of dermal nitric oxide application. We characterized with human skin in vitro and in vivo the capacity of NO, applied in a NO-releasing acidified form of nitrite-containing liniments, to penetrate the epidermis and to influence local as well as systemic hemodynamic parameters. We found that dermal application of NO led to a very rapid and significant transepidermal translocation of NO into the underlying tissue. Depending on the size of treated skin area, this translocation manifests itself through a significant systemic increase of the NO derivates nitrite and nitroso compounds, respectively. In parallel, this translocation was accompanied by an increased systemic vasodilatation and blood flow as well as reduced blood pressure. We here give evidence that in humans dermal application of NO has a therapeutic potential for systemic hemodynamic disorders that might arise from local or systemic insufficient availability of NO or its bio-active NO derivates, respectively. Copyright © 2012 Elsevier Inc. All rights reserved.

Synthesis, biological evaluation and molecular docking studies of ...

African Journals Online (AJOL)

Synthesis, biological evaluation and molecular docking studies of Mannich bases derived from 1, 3, 4-oxadiazole- 2-thiones as potential urease inhibitors. ... Mannich bases (5-17) were subjected to in silico screening as urease inhibitors, using crystal structure of urease (Protein Data Bank ID: 5FSE) as a model enzyme.

Application of 13C-urea breath test in patients diagnosed as H. pylori-negative by gastroscopy

International Nuclear Information System (INIS)

Li Long; Liu Changjiang; Gao Jianqing; Xu Sumei; Chen Linna; Zhou Jianming

2006-01-01

13 C-urea breath test( 13 C-UBT)was used to evaluate infection rate of H. pylori(HP) and effect of HP eradication in patients diagnosed as HP-negative by histology and rapid urease test. Patiens without gastrointestinal disorders were set as control group. Within 640 patients diagnosed as HP-negative by histology and rapid urease test, there were 389 patients showed HP-positive by 13 C-UBT. The positive rate of HP was 60.8%. 389 patients diagnosed as HP- positive by 13 C-UBT were treated with PPI-based triple therapy, PPI-based double therapy and single PPI therapy, respectively. After treatment, the negative rate of 13 C-UBT was 83.8%, 18.4% and 3.3%, respectively. The results showed significant difference between three kinds of therapy (P 13 C-UBT could improve the diagnostic rate of HP to patients who diagnosed as HP-negative by histology and rapid urease test. (authors)

Expanded metabolic versatility of ubiquitous nitrite-oxidizing bacteria from the genus Nitrospira

DEFF Research Database (Denmark)

Koch, Hanna; Lücker, Sebastian; Albertsen, Mads

2015-01-01

, we identified ecophysiological traits that contribute to the ecological success of Nitrospira. Unexpectedly, N. moscoviensis possesses genes coding for a urease and cleaves urea to ammonia and CO2. Ureolysis was not observed yet in nitrite oxidizers and enables N. moscoviensis to supply ammonia...... oxidizers lacking urease with ammonia from urea, which is fully nitrified by this consortium through reciprocal feeding. The presence of highly similar urease genes in Nitrospira lenta from activated sludge, in metagenomes from soils and freshwater habitats, and of other ureases in marine nitrite oxidizers...

Role of inhibitors and biodegradable material in mitigation of ...

African Journals Online (AJOL)

Loss of N, occurring mainly through NH3 volatilization, biological denitrification, and NO3 - leaching, has both economic and environmental implications. Therefore, the economic benefits of reduced environmental pollution and future damage to our environment as a result of the use of urease inhibitors are of higher ...

Cerebral Embolic Protection During Transcatheter Aortic Valve Replacement Significantly Reduces Death and Stroke Compared With Unprotected Procedures.

Science.gov (United States)

Seeger, Julia; Gonska, Birgid; Otto, Markus; Rottbauer, Wolfgang; Wöhrle, Jochen

2017-11-27

The aim of this study was to evaluate the impact of cerebral embolic protection on stroke-free survival in patients undergoing transcatheter aortic valve replacement (TAVR). Imaging data on cerebral embolic protection devices have demonstrated a significant reduction in number and volume of cerebral lesions. A total of 802 consecutive patients were enrolled. The Sentinel cerebral embolic protection device (Claret Medical Inc., Santa Rosa, California) was used in 34.9% (n = 280) of consecutive patients. In 65.1% (n = 522) of patients TAVR was performed in the identical setting except without cerebral embolic protection. Neurological follow-up was done within 7 days post-procedure. The primary endpoint was a composite of all-cause mortality or all-stroke according to Valve Academic Research Consortium-2 criteria within 7 days. Propensity score matching was performed to account for possible confounders. Both filters of the device were successfully positioned in 280 of 305 (91.8%) consecutive patients. With use of cerebral embolic protection rate of disabling and nondisabling stroke was significantly reduced from 4.6% to 1.4% (p = 0.03; odds ratio: 0.29, 95% confidence interval: 0.10 to 0.93) in the propensity-matched population (n = 560). The primary endpoint occurred significantly less frequently, with 2.1% (n = 6 of 280) in the protected group compared with 6.8% (n = 19 of 280) in the control group (p = 0.01; odds ratio: 0.30; 95% confidence interval: 0.12 to 0.77). In multivariable analysis Society of Thoracic Surgeons score for mortality (p = 0.02) and TAVR without protection (p = 0.02) were independent predictors for the primary endpoint. In patients undergoing TAVR use of a cerebral embolic protection device demonstrated a significant higher rate of stroke-free survival compared with unprotected TAVR. Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Soil nitrate reducing processes drivers, mechanisms for spatial variation, and significance for nitrous oxide production

OpenAIRE

Giles, M.; Morley, N.; Baggs, E.M.; Daniell, T.J.

2012-01-01

The microbial processes of denitrification and dissimilatory nitrate reduction to ammonium\\ud (DNRA) are two important nitrate reducing mechanisms in soil, which are responsible for\\ud the loss of nitrate (NO−\\ud 3 ) and production of the potent greenhouse gas, nitrous oxide (N2O).\\ud A number of factors are known to control these processes, including O2 concentrations and\\ud moisture content, N, C, pH, and the size and community structure of nitrate reducing organisms\\ud responsible for the ...

Synthesis, Characterization and Biological Activities of Creatinine Amides and Creatinine Schiff Bases.

Science.gov (United States)

Mumtaz, Amara; Zahoor, Fareeha; Zaib, Sumera; Nawaz, Muhammad Azhar H; Saeed, Aamer; Waseem, Amir; Khan, Afsar; Hussain, Izhar; Iqbal, Jamshed

2017-01-30

In spite of substantial progress in scientific cognizance and medical technology, still infectious diseases are among the leading cause of morbidity and mortality. Creatinine and Schiff bases are well known for their diverse range of biological activities and thought to be emerging and useful therapeutic target for the treatment of several diseases. The present work was aimed to illustrate the influence of substitution of amides and Schiff bases on creatinine and their antimicrobial, antioxidant and anti-urease effectiveness was determined. Creatinine substituted amides (1-2) and creatinine Schiff bases (3-7) were synthesized and characterized by NMR and IR spectral data in combination with elemental analysis. All the compounds (1-7) were investigated on Jack bean urease for their urease inhibitory potential. Investigation of antimicrobial activity of the compounds was made by the agar dilution method. Moreover, 1,1-diphenyl-2- picrylhydrazyl (DPPH) method was used to determine their antioxidant potential. Molecular docking studies were also carried out to elucidate their relationship with the binding pockets of the enzyme. The compounds were found to be potent inhibitors of urease. The synthesized derivatives exhibited significant inhibition against Gram-positive and Gram-negative bacterial strains, as compared to standard, ciprofloxacin. Creatinine based derivatives exhibited potential antifungal activity when tested on infectious and pathogenic fungal strains. Similarly, most of the compounds exhibited good antioxidant activity. These derivatives may serve as a source of potential antioxidants and also help to retard microbial growth in food industry. Similarly, the studies provide a basis for further research to develop more potent urease inhibitory compounds of medicinal /agricultural interest. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Prenatal prochloraz treatment significantly increases pregnancy length and reduces offspring weight but does not affect social-olfactory memory in rats

DEFF Research Database (Denmark)

Dmytriyeva, Oksana; Klementiev, Boris; Berezin, Vladimir

2013-01-01

Metabolites of the commonly used imidazole fungicide prochloraz are androgen receptor antagonists. They have been shown to block androgen-driven development and compromise reproductive function. We tested the effect of prochloraz on cognitive behavior following exposure to this fungicide during...... the perinatal period. Pregnant Wistar rats were administered a 200mg/kg dose of prochloraz on gestational day (GD) 7, GD11, and GD15. The social recognition test (SRT) was performed on 7-week-old male rat offspring. We found an increase in pregnancy length and a significantly reduced pup weight on PND15 and PND...

Diagnosis of Helicobacter pylori infection in patients with bleeding ulcer disease: rapid urease test and histology Diagnóstico mediante endoscopia de la infección por Helicobacter pylori en pacientes con úlcera gastroduodenal y hemorragia digestiva: test rápido de ureasa e histología

Directory of Open Access Journals (Sweden)

M. Castro-Fernández

2004-06-01

Full Text Available Introduction: the endoscopic diagnosis of Helicobacter pylori infection in patients with bleeding peptic ulcer is limited by a decreased sensitivity in standard invasive tests, rapid urease test and histology. There is controversy about the convenience of using one, neither, or both diagnostic tests. Aims: to evaluate the results of simultaneously performed rapid urease test and histology in the diagnosis of Helicobacter pylori infection (H. pylori in patients with bleeding peptic ulcer. Patients and methods: we included 173 patients, 98 male and 75 female, with an average age of 62 years (18-88, with upper gastrointestinal bleeding secondary to duodenal ulcer (115 or gastric ulcer (58, diagnosed within 24 hours after hospital admission. None of the patients had received treatment for H. pylori, proton pump inhibitors or antibiotics in the two weeks prior to the upper gastrointestinal bleeding episode. H. pylori infection was investigated in all patients by two antral biopsy samples for histological study (hematoxilin-eosin and one or two antral biopsies for rapid urease test (Jatrox®-H.p.-test. In cases with a negative urease test and histology, a 13C urea breath test was performed. Infection was considered present when at least one invasive test or the breath test was positive, whereas both invasive tests and the breath test had to be negative to establish an absent infection. Results: 152 patients (88% showed H. pylori infection, 104 patients (90% with duodenal ulcer and 48 patients (83% with gastric ulcer. In all 119 cases (78% were diagnosed by the urease test and 112 cases (74% by histology. Both methods were used to diagnose 134 of 152 cases (88% (p Introducción: el diagnóstico de la infección por Helicobacter pylori, mediante endoscopia, en pacientes con úlcera gastroduodenal y hemorragia digestiva está limitado por la disminución de la sensibilidad de los métodos invasivos habituales, test de la ureasa e histología. Existen

Ecotoxicological effects of copper and selenium combined pollution on soil enzyme activities in planted and unplanted soils.

Science.gov (United States)

Hu, Bin; Liang, Dongli; Liu, Juanjuan; Xie, Junyu

2013-04-01

The present study explored the joint effects of Cu and Se pollution mechanisms on soil enzymes to provide references for the phytoremediation of contaminated areas and agricultural environmental protection. Pot experiments and laboratory analyses were carried out to study the individual and combined influences of Cu and Se on soil enzyme activities. The activities of four soil enzymes (urease, catalase, alkaline phosphatase, and nitrate reductase) were chosen. All soil enzyme activities tested were inhibited by Cu and Se pollution, either individually or combined, in varying degrees, following the order nitrate reductase>urease>catalase>alkaline phosphatase. Growing plants stimulated soil enzyme activity in a similar trend compared with treatments without plants. The joint effects of Cu and Se on catalase activity showed synergism at low concentrations and antagonism at high concentrations, whereas the opposite was observed for urease activity. However, nitrate reductase activity showed synergism both with and without plant treatments. The half maximal effective concentration (EC50) of exchangeable fractions had a similar trend with the EC50 of total content and was lower than that of total content. The EC50 values of nitrate reductase and urease activities were significantly lower for both Se and Cu (p<0.05), which indicated that they were more sensitive than the other two enzymes. Copyright © 2013 SETAC.

Dynamic of biochemical soil properties in rainfed agave angustifolia haw. fields in semiard zone

International Nuclear Information System (INIS)

Cruz, A. B.; Cervantes, T. L.; Pacheco, R. P.; Martinez, M. D. L. R.; Perez, A. B.

2015-01-01

This study determined (a) the activity of the selected enzymes of C (invertase and cellulase), N (urease), P (acid phosphatase, AcP and alkaline phosphatase, AlkP) cycling, as well as soil microbial biomass carbon (SMBC) in the rhizosphere of Agave angustifolia Haw. (maguey espadin) cultivated in valley, hill and mountain soils in Tlacolula, Oaxaca (Mexico), and (b) changes in selected biochemical soil properties associated with seasonality and plant age. Three maguey espadin plantations with two replicates per topography were selected. Rhizosphere soil sampling was carried out for one year. AcP and urease activities were highest in mountain sites. AlkP and cellulase activities were highest in hill and mountain sites. Invertase activity and SMBC were not different among sites. Phosphatase activity showed no temporal changes. Cellulase and invertase activities were highest in December; maximum urease activity was in October and February. SMBC was highest in August. AcP activity was highest in 0-2 years old plants. AlkP activity and SMBC were highest in 2.1-4 years old plants. Urease, cellulase and invertase activity was not affected by plant age. Significant effects for the site*seasonality*plant age interaction suggest that biochemical soil properties were influenced by site. Mountain soils displayed the highest enzyme activity, which can accelerate soil organic matter turnover and contribute to the longterm sustainability of maguey espadin cropping under rainfed conditions. (author)

Tailoring of analytical performances of urea biosensors using nanomaterials

International Nuclear Information System (INIS)

Nouira, W; Barhoumi, H; Maaref, A; Renault, N Jaffrézic; Siadat, M

2013-01-01

This paper is a contribution to the study of enzymatic sensors based on nanoparticles of iron oxide (FeNPs). Urease enzyme was immobilized on FeNPs using layer-by-layer (LbL) deposition method. FeNPs were first coated with polyelectrolytes (PE): Poly (allylamine hydrochloride), PAH and Poly (sodium 4-styrenesulfonate), PSS for enzyme immobilization and then with enzyme. It has been confirmed through zeta potential measurements of FeNPs that the enzyme is immobilized on the surface. We evaluated the sensitivity of biosensors for urea by potentiometric and capacitive measurements on silicon / silica / FeNP-LBL-urease structures. The recorded capacity-potential curves (C-V) show a significant shift of flat band potential towards negative potentials in the presence of urea, the observed values of sensitivity vary between 30 and 40 mV/p[urea]. It has been shown that the proposed method for the immobilization of urease can increase the dynamic range of urea detection (10 −4 M to 10 −1 M) compared to the immobilization of urease without FeNP (10 −3.5 M to 10 −2.5 M). When the number of PAH-PSS layers was increased the sensitivity of detection was modified. This effect is due to partial inhibition of the enzyme in presence of FeNPs, which was shown by measurements in homogeneous phase.

Use of CdSe/ZnS luminescent quantum dots incorporated within sol-gel matrix for urea detection

International Nuclear Information System (INIS)

Duong, Hong Dinh; Rhee, Jong Il

2008-01-01

In this work, urea detection techniques based on the pH sensitivity of CdSe/ZnS QDs were developed using three types of sol-gel membranes: a QD-entrapped membrane, urease-immobilized membrane and double layer consisting of a QD-entrapped membrane and urease-immobilized membrane. The surface morphology of the sol-gel membranes deposited on the wells in a 24-well microtiter plate was investigated. The linear detection range of urea was in the range of 0-10 mM with the three types of sol-gel membranes. The urea detection technique based on the double layer consisting of the QD-entrapped membrane and urease-immobilized membrane resulted in the highest sensitivity to urea due to the Michaelis-Menten kinetic parameters. That is, the Michaelis-Menten constant (K m =2.0745 mM) of the free urease in the QD-entrapped membrane was about 4-fold higher than that (K m =0.549 mM) of the immobilized urease in the urease-immobilized membrane and about 12-fold higher than that (K m =0.1698 mM) of the immobilized urease in the double layer. The good stability of the three sol-gel membranes for urea sensing over 2 months showed that the use of sol-gel membranes immobilized with QDs or an enzyme is suitable for biomedical and environmental applications

Use of CdSe/ZnS luminescent quantum dots incorporated within sol-gel matrix for urea detection.

Science.gov (United States)

Duong, Hong Dinh; Rhee, Jong Il

2008-09-19

In this work, urea detection techniques based on the pH sensitivity of CdSe/ZnS QDs were developed using three types of sol-gel membranes: a QD-entrapped membrane, urease-immobilized membrane and double layer consisting of a QD-entrapped membrane and urease-immobilized membrane. The surface morphology of the sol-gel membranes deposited on the wells in a 24-well microtiter plate was investigated. The linear detection range of urea was in the range of 0-10mM with the three types of sol-gel membranes. The urea detection technique based on the double layer consisting of the QD-entrapped membrane and urease-immobilized membrane resulted in the highest sensitivity to urea due to the Michaelis-Menten kinetic parameters. That is, the Michaelis-Menten constant (K(m)=2.0745mM) of the free urease in the QD-entrapped membrane was about 4-fold higher than that (K(m)=0.549mM) of the immobilized urease in the urease-immobilized membrane and about 12-fold higher than that (K(m)=0.1698mM) of the immobilized urease in the double layer. The good stability of the three sol-gel membranes for urea sensing over 2 months showed that the use of sol-gel membranes immobilized with QDs or an enzyme is suitable for biomedical and environmental applications.

Reduced frontal and occipital lobe asymmetry on the CT-scans of schizophrenic patients. Its specificity and clinical significance

International Nuclear Information System (INIS)

Falkai, P.; Schneider, T.; Greve, B.; Klieser, E.; Bogerts, B.

1995-01-01

Frontal and occipital lobe widths were determined in the computed tomographic (CT) scans of 135 schizophrenic patients, 158 neuro psychiatrically healthy and 102 psychiatric control subjects, including patients with affective psychosis, neurosis and schizoaffective psychosis. Most healthy right-handed subjects demonstrate a relative enlargement of the right frontal as well as left occipital lobe compared to the opposite hemisphere. These normal frontal and occipital lobe asymmetries were selectively reduced in schizophrenics (f.: 5%, p < .0005; o.: 3%, p < .05), irrespective of the pathophysiological subgroup. Schizophrenic neuroleptic non-responders revealed a significant reduction of frontal lobe asymmetry (3%, p < .05), while no correlation between BPRS-sub scores and disturbed cerebral laterality could be detected. In sum the present study demonstrates the disturbed cerebral lateralisation in schizophrenic patients supporting the hypothesis of interrupted early brain development in schizophrenia. (author)

Reducing dysfunctional beliefs about sleep does not significantly improve insomnia in cognitive behavioral therapy.

Science.gov (United States)

Okajima, Isa; Nakajima, Shun; Ochi, Moeko; Inoue, Yuichi

2014-01-01

The present study examined to examine whether improvement of insomnia is mediated by a reduction in sleep-related dysfunctional beliefs through cognitive behavioral therapy for insomnia. In total, 64 patients with chronic insomnia received cognitive behavioral therapy for insomnia consisting of 6 biweekly individual treatment sessions of 50 minutes in length. Participants were asked to complete the Athens Insomnia Scale and the Dysfunctional Beliefs and Attitudes about Sleep scale both at the baseline and at the end of treatment. The results showed that although cognitive behavioral therapy for insomnia greatly reduced individuals' scores on both scales, the decrease in dysfunctional beliefs and attitudes about sleep with treatment did not seem to mediate improvement in insomnia. The findings suggest that sleep-related dysfunctional beliefs endorsed by patients with chronic insomnia may be attenuated by cognitive behavioral therapy for insomnia, but changes in such beliefs are not likely to play a crucial role in reducing the severity of insomnia.

Diagnosis of Helicobacter pylori infection

International Nuclear Information System (INIS)

Nysaeter, G.; Berstad, K.; Weberg, R.; Berstad, A.; Hardardottir, H.

1992-01-01

By employing the 14 C-urea breath test as the reference methods the authors determined the specificity and sensitivity of three bioptic methods for diagnosis of Helicobacter pylori infection in 103 subjects. All biopsy specimens were obtained from the gastric antrum. For culture the specificity was 100%. Its applicability was reduced, however, by a low sensitivity (73.8%) and a delay of several days before the final result was available. Microscopy of Loeffler-stained biopsy smears yielded a specificity of 100% and a sensitivity of 92.9%, but the method was regarded time-consuming. The rapid urease test yielded a specificity of 98.4% and a sensitivity of 85.7%. Being quick, simple and inexpensive, the rapid urease test is well suited for routine use in gastroscopy. 17 refs., 4 tabs

Avaliação de fontes de amônia para o tratamento de fenos de gramíneas tropicais. 1. Constituintes da parede celular, poder tampão e atividade ureática Evaluation of ammonia sources to tropical grasses hays treatment. 1. Cell wall contents, buffer capacity and urease activity

Directory of Open Access Journals (Sweden)

Ricardo Andrade Reis

2001-06-01

Full Text Available Avaliaram-se as alterações da fração fibrosa e as características químicas dos fenos de braquiária decumbens (Brachiaria decumbnes Stapf e jaraguá (Hyparrhenia rufa Ness Stapf não-tratados, tratados com uréia (U-5,4% da MS, uréia (UL-5,4% da MS mais labe-labe (Lablab purpureus L. Sweet, cv. Highworth-3,0% da MS ou amônia anidra (NH3 -3,0% da MS. O tratamento químico com uréia ou NH3 aumentou o pH e a digestibilidade in vitro verdadeira dos fenos. A amonização não alterou os teores de fibra em detergente ácido e celulose, mas diminuiu os de fibra em detergente neutro, hemicelulose e lignina. O uso do labe-labe como fonte adicional de urease não aumentou a eficiência da uréia no tratamento dos volumosos. As avaliações do conteúdo de umidade, do poder tampão e da atividade ureática são técnicas que podem auxiliar na previsão das respostas dos volumosos à amonização com o uso de uréia.The experiment was conducted to evaluate the changes on the chemical composition and the in vitro dry matter digestibility (IVDMD of the Brachiaria decumbens Stapf, jaraguá (Hyparrhenia rufa Ness Stapf hays, untreated, treated with urea (5.4% DM, urea (UL-5.4% DM and lab lab (Lablab purpureus L. Sweet, cv. Highworth-3.0% DM; and anhydrous ammonia (NH3 3.0% DM. The chemical treatment increased the pH and the in vitro digestibility of the hays Ammoniation did not affect ADF and cellulose contents. The NDF, hemicellulose and lignin contents decreased due to ammoniation with NH3. The urea utilization had the same efficiency that anhydrous ammonia on the hemicellulose content of the hays. The use of an external source of urease did not affect the urea treatment efficiency. The evaluation of the chemical characteristics of the forages, as the dry matter content, buffering capacity, and urease activity can be helpful on the prediction of their responses to the ammoniation.

The Influence of Visible Light on the Sulfhydryl Content of Yeast Cells After Ionizing and Ultraviolet Irradiation

Science.gov (United States)

1951-12-15

be irradiated. ?A liquid filter consisting of a 1 cm layer of 5% CUSO4 was used to remove most of the infrared. F. Cell Counts n f. The...Protein sulfhydryl groups and the reversible inactivation of the enzyme „our ease. The reducing groups of egg albumin and of urease . Jt

Biomasa microbiana y actividad ureasa del suelo en una pradera permanente pastoreada de Chile Soil microbial biomass and urease activity in a grazed permanent pasture from Chile

Directory of Open Access Journals (Sweden)

Pedro Antonio Núñez Ramos

2012-12-01

Full Text Available En los sistemas de pasturas; la productividad de la pradera puede estar influenciada por el manejo; debido a su impacto sobre los microorganismos del suelo y el reciclaje de nutrientes. El objetivo de este trabajo fue evaluar la biomasa microbiana (BM del suelo asociada al nitrógeno (BMN; carbono (BMC y la actividad ureasa (AU en una pradera permanente del sur de Chile. Entre la primavera de 2005 y el invierno de 2006 fueron evaluados dos sistemas de pastoreo: pastoreo intenso (PI; pastoreo suave (PS y un tratamiento control (C. El diseño fue en bloques al azar con tres repeticiones. En relación a los valores promedios medidos de las variables en pre y post pastoreo; se produjo un incremento en los contenidos de CB en un 21,8 y 8,6% para PI y PS; mientras que en el control fue sólo de 1,9%. Los contenidos de NB también fueron incrementados en un 16 y 19% para PI y PS; respectivamente en comparación con el control (4%. La actividad ureasa aumentó en 13 y 27% para PI y PS; respectivamente en comparación con el control (5%. El pastoreo; produce un flujo más alto de residuos orgánicos en el suelo; lo que estimula la actividad de la biomasa microbiana y; por tanto; aumentó la AU y los contenidos de CB y NB. Esto sugiere que; en los sistemas de pastoreo; se mejora la fertilidad biológica de los suelos y la disponibilidad de nutrientes.In pasture systems, management practices can affect pasture productivity differently due to their impact on soil microorganisms and nutrient cycling. The objective of this study was to evaluate the relationship between soil microbial biomass (MB nitrogen (MBN, carbon (MBC and urease activity (UA in a permanent pasture in southern Chile. Two grazing systems were evaluated between spring 2005 and winter 2006 : heavy grazing (HG, light grazing (LG and a control treatment (C. Treatments were arranged in a randomized block design with three replications. Concerning the average values of the variables measured at

Impact of chlortetracycline and sulfapyridine antibiotics on soil enzyme activities

Science.gov (United States)

Molaei, Ali; Lakzian, Amir; Datta, Rahul; Haghnia, Gholamhosain; Astaraei, Alireza; Rasouli-Sadaghiani, MirHassan; Ceccherini, Maria T.

2017-10-01

Pharmaceutical antibiotics are frequently used in the livestock and poultry industries to control infectious diseases. Due to the lack of proper guidance for use, the majority of administrated antibiotics and their metabolites are excreted to the soil environment through urine and feces. In the present study, we used chlortetracycline and sulfapyridine antibiotics to screen out their effects on dehydrogenase, alkaline phosphatase and urease activity. Factorial experiments were conducted with different concentrations of antibiotic (0, 10, 25 and 100 mg kg-1 of soil) mixed with soil samples, and the enzyme activity was measured at intervals of 1, 4 and 21 days. The results show that the chlortetracycline and sulfapyridine antibiotics negatively affect the dehydrogenase activity, but the effect of sulfapyridine decreases with time of incubation. Indeed, sulfapyridine antibiotic significantly affect the alkaline phosphatase activity for the entire three-time interval, while chlortetracycline seems to inhibit its activity within 1 and 4 days of incubation. The effects of chlortetracycline and sulfapyridine antibiotics on urease activity appear similar, as they both significantly affect the urease activity on day 1 of incubation. The present study concludes that chlortetracycline and sulfapyridine antibiotics have harmful effects on soil microbes, with the extent of effects varying with the duration of incubation and the type of antibiotics used.

Diagnosis of Helicobacter pylori infection using urease rapid test in patients with bleeding duodenal ulcer: influence of endoscopic signs and simultaneous corporal and antral biopsies Diagnóstico de la infección por Helicobacter pylori mediante el test rápido de la ureasa en pacientes con hemorragia por úlcera duodenal: influencia de los signos endoscópicos de sangrado y de la obtención simultánea de biopsias de cuerpo y antro gástrico

Directory of Open Access Journals (Sweden)

M. Castro Fernández

2004-09-01

Full Text Available Introduction: the sensitivity of invasive diagnostic methods for Helicobacter pylori (H. pylori infection, particularly of urease rapid test, is decreased in cases of gastroduodenal ulcer and upper gastrointestinal bleeding. Objectives: to assess the influence of blood in the stomach or recent bleeding endoscopic signs in the diagnostic sensitivity of urease rapid test among patients with bleeding duodenal ulcer, as well as the influence of simultaneously collected corporal and antral biopsy samples. Patients and methods: 120 patients, 85 male and 35 female, with an average age of 62 (18-88 years, who were admitted to our Hospital due to bleeding duodenal ulcer and who received an endoscopic diagnosis within 24 hours of admission were included. None of the patients had been under treatment with non-steroideal antiinflammatory drugs, proton-pump inhibitors or antimicrobial drugs in the two weeks prior to the bleeding event, and none had received eradicating therapy for H. pylori. In this group of selected patients an H. pylori infection rate nearing 100% was assumed. H. pylori infection was ruled out using antral biopsy (69 cases or both antral and fundic biopsies (51 cases for urease rapid testing (Jatrox®-H.p.-Test. Patients were classified in three groups according to their endoscopic bleeding signs: a presence of blood in the stomach or recent bleeding ulcer (21 cases; b ulcer showing non-recent bleeding signs (38 cases; and c ulcer without bleeding signs (61 cases. The sensitivity of the urease rapid test was compared between patient groups. Similarly, urease test results with an antral biopsy sample were compared in 100 patients with non-bleeding duodenal ulcer. Results: urease test was positive in 93% of patients with non-bleeding duodenal ulcer, and in 83% of patients with upper gastrointestinal bleeding, which reached statistical significance (p = 0.019. This test was positive in 82.6% of patients with an antral biopsy, and in 82.3% of

Significant change of local atomic configurations at surface of reduced activation Eurofer steels induced by hydrogenation treatments

Energy Technology Data Exchange (ETDEWEB)

Greculeasa, S.G.; Palade, P.; Schinteie, G. [National Institute for Materials Physics, P.O. Box MG-7, 77125, Bucharest-Magurele (Romania); Kuncser, A.; Stanciu, A. [National Institute for Materials Physics, P.O. Box MG-7, 77125, Bucharest-Magurele (Romania); University of Bucharest, Faculty of Physics, 77125, Bucharest-Magurele (Romania); Lungu, G.A. [National Institute for Materials Physics, P.O. Box MG-7, 77125, Bucharest-Magurele (Romania); Porosnicu, C.; Lungu, C.P. [National Institute for Laser, Plasma and Radiation Physics, 77125, Bucharest-Magurele (Romania); Kuncser, V., E-mail: kuncser@infim.ro [National Institute for Materials Physics, P.O. Box MG-7, 77125, Bucharest-Magurele (Romania)

2017-04-30

Highlights: • Engineering of Eurofer slab properties by hydrogenation treatments. • Hydrogenation modifies significantly the local atomic configurations at the surface. • Hydrogenation increases the expulsion of the Cr atoms toward the very surface. • Approaching binomial atomic distribution by hydrogenation in the next surface 100 nm. - Abstract: Reduced-activation steels such as Eurofer alloys are candidates for supporting plasma facing components in tokamak-like nuclear fusion reactors. In order to investigate the impact of hydrogen/deuterium insertion in their crystalline lattice, annealing treatments in hydrogen atmosphere have been applied on Eurofer slabs. The resulting samples have been analyzed with respect to local structure and atomic configuration both before and after successive annealing treatments, by X-ray diffractometry (XRD), scanning electron microscopy and energy dispersive spectroscopy (SEM-EDS), X-ray photoelectron spectroscopy (XPS) and conversion electron Mössbauer spectroscopy (CEMS). The corroborated data point out for a bcc type structure of the non-hydrogenated alloy, with an average alloy composition approaching Fe{sub 0.9}Cr{sub 0.1} along a depth of about 100 nm. EDS elemental maps do not indicate surface inhomogeneities in concentration whereas the Mössbauer spectra prove significant deviations from a homogeneous alloying. The hydrogenation increases the expulsion of the Cr atoms toward the surface layer and decreases their oxidation, with considerable influence on the surface properties of the steel. The hydrogenation treatment is therefore proposed as a potential alternative for a convenient engineering of the surface of different Fe-Cr based alloys.

Soil nitrate reducing processes – drivers, mechanisms for spatial variation, and significance for nitrous oxide production

Science.gov (United States)

Giles, Madeline; Morley, Nicholas; Baggs, Elizabeth M.; Daniell, Tim J.

2012-01-01

The microbial processes of denitrification and dissimilatory nitrate reduction to ammonium (DNRA) are two important nitrate reducing mechanisms in soil, which are responsible for the loss of nitrate (NO3−) and production of the potent greenhouse gas, nitrous oxide (N2O). A number of factors are known to control these processes, including O2 concentrations and moisture content, N, C, pH, and the size and community structure of nitrate reducing organisms responsible for the processes. There is an increasing understanding associated with many of these controls on flux through the nitrogen cycle in soil systems. However, there remains uncertainty about how the nitrate reducing communities are linked to environmental variables and the flux of products from these processes. The high spatial variability of environmental controls and microbial communities across small sub centimeter areas of soil may prove to be critical in determining why an understanding of the links between biotic and abiotic controls has proved elusive. This spatial effect is often overlooked as a driver of nitrate reducing processes. An increased knowledge of the effects of spatial heterogeneity in soil on nitrate reduction processes will be fundamental in understanding the drivers, location, and potential for N2O production from soils. PMID:23264770

Soil nitrate reducing processes – drivers, mechanisms for spatial variation and significance for nitrous oxide production

Directory of Open Access Journals (Sweden)

Madeline Eleanore Giles

2012-12-01

Full Text Available The microbial processes of denitrification and dissimilatory nitrate reduction to ammonium (DNRA are two important nitrate reducing mechanisms in soil, which are responsible for the loss of nitrate (NO3-¬ and production of the potent greenhouse gas, nitrous oxide (N2O. A number of factors are known to control these processes, including O2 concentrations and moisture content, N, C, pH and the size and community structure of nitrate reducing organisms responsible for the processes. There is an increasing understanding associated with many of these controls on flux through the nitrogen cycle in soil systems. However, there remains uncertainty about how the nitrate reducing communities are linked to environmental variables and the flux of products from these processes. The high spatial variability of environmental controls and microbial communities across small sub cm areas of soil may prove to be critical in determining why an understanding of the links between biotic and abiotic controls has proved elusive. This spatial effect is often overlooked as a driver of nitrate reducing processes. An increased knowledge of the effects of spatial heterogeneity in soil on nitrate reduction processes will be fundamental in understanding the drivers, location and potential for N2O production from soils.

Optical trapping of nanoparticles with significantly reduced laser powers by using counter-propagating beams (Presentation Recording)

Science.gov (United States)

Zhao, Chenglong; LeBrun, Thomas W.

2015-08-01

Gold nanoparticles (GNP) have wide applications ranging from nanoscale heating to cancer therapy and biological sensing. Optical trapping of GNPs as small as 18 nm has been successfully achieved with laser power as high as 855 mW, but such high powers can damage trapped particles (particularly biological systems) as well heat the fluid, thereby destabilizing the trap. In this article, we show that counter propagating beams (CPB) can successfully trap GNP with laser powers reduced by a factor of 50 compared to that with a single beam. The trapping position of a GNP inside a counter-propagating trap can be easily modulated by either changing the relative power or position of the two beams. Furthermore, we find that under our conditions while a single-beam most stably traps a single particle, the counter-propagating beam can more easily trap multiple particles. This (CPB) trap is compatible with the feedback control system we recently demonstrated to increase the trapping lifetimes of nanoparticles by more than an order of magnitude. Thus, we believe that the future development of advanced trapping techniques combining counter-propagating traps together with control systems should significantly extend the capabilities of optical manipulation of nanoparticles for prototyping and testing 3D nanodevices and bio-sensing.

Improving soil enzyme activities and related quality properties of reclaimed soil by applying weathered coal in opencast-mining areas of the Chinese loess plateau

Energy Technology Data Exchange (ETDEWEB)

Li, Hua [College of Environment and Resources, Shanxi University, Taiyuan (China); CAS/Shandong Provincial Key Laboratory of Coastal Environmental Process, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences (CAS), Yantai (China); Shao, Hongbo [CAS/Shandong Provincial Key Laboratory of Coastal Environmental Process, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences (CAS), Yantai (China); Institute for Life Sciences, Qingdao University of Science and Technology (QUST), Qingdao (China); Li, Weixiang; Bi, Rutian [Shanxi Agricultural University, Taigu (China); Bai, Zhongke [Department of Land Science Technology, University of Geosciences, Beijing (China)

2012-03-15

There are many problems for the reclaimed soil in opencast-mining areas of the Loess Plateau of China such as poor soil structure and extreme poverty in soil nutrients and so on. For the sake of finding a better way to improve soil quality, the current study was to apply the weathered coal for repairing soil media and investigate the physicochemical properties of the reclaimed soil and the changes in enzyme activities after planting Robinia pseucdoacacia. The results showed that the application of the weathered coal significantly improved the quality of soil aggregates, increased the content of water stable aggregates, and the organic matter, humus, and the cation exchange capacity of topsoil were significantly improved, but it did not have a significant effect on soil pH. Planting R. pseucdoacacia significantly enhanced the activities of soil catalase, urease, and invertase, but the application of the weathered coal inhibited the activity of catalase. Although the application of appropriate weathered coal was able to significantly increase urease activity, the activities of catalase, urease, or invertase had a close link with the soil profile levels and time. This study suggests that applying weathered coals could improve the physicochemical properties and soil enzyme activities of the reclaimed soil in opencast-mining areas of the Loess Plateau of China and the optimum applied amount of the weathered coal for reclaimed soil remediation is about 27 000 kg hm{sup -2}. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Influence of Different soil Management Effects on Chemical Parameters and Soil Enzyme Activities in a Long-Time Viticultural Trial. Part I: The Lanes

Directory of Open Access Journals (Sweden)

Klaus Schaller

2016-11-01

Biological activity was determined with enzyme assays. Glucosidases are significantly higher in grassed plots and extensive tilling; same is true for phosphatases. Urease is also highest in grassed plots and extensive tilling. A strong and significant stratification with soil depth could be demonstrated for all analyzed parameters.

Evaluation of diagnostic methods for the detection of Helicobacter pylori in gastric biopsy specimens of dyspeptic patients