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Urease is a kind of nickel-dependent metalloenzyme, which exists in the biological world widely, and can catalyse the hydrolysis of urea into ammonia and carbon dioxide to provide a nitrogen source for organisms. Urease has important uses in agriculture and medicine because it can catalyse the production of ammonia. Therefore, in this review, metal-based inhibitors of urease will be summarised according to different transition metal ions. Including the urease inhibition, structure-activity relationship, and molecular docking. Importantly, among these reviewed effective urease inhibitors, most of copper metal complexes exhibited stronger urease inhibition with IC

Aims Soil microbial communities are among the most diverse communities that might be affected due to transgenic crops. Therefore, risk assessment studies on transgenes are essentially required as any adverse effects may depend not only on the specific gene and crop involved but also on soil conditions. Methods and results The present study deals with the comparison of bacterial populations, root exudates and activities of soil enzymes in nontransgenic and AVP1-transgenic wheat rhizosphere, overexpressing vacuolar H + pyrophosphatase for salinity and drought stress tolerance. Amounts of organic acids and sugars produced as root exudates and activities of dehydrogenase, phosphatase and protease enzymes in soil solution showed no significant differences in AVP1-transgenic and nontransgenic wheat rhizosphere, except for urease and phenol oxidase activities. The higher copy number of nifH gene showed the abundance of nitrogen-fixing bacteria in the rhizosphere of AVP1-transgenic wheat compared with nontransgenic wheat. nifH gene sequence analysis indicated the common diazotrophic genera Azospirillum, Bradyrhizobium, Rhizobium and Pseudomonas in AVP1-transgenic and nontransgenic wheat except for Zoogloea detected only in nontransgenic wheat. Using 454-pyrosequencing of 16S rRNA gene from soil DNA, a total of 156, 282 sequences of 18 phyla were obtained, which represented bacterial (128,006), Archeal (7928) and unclassified (21,568) sequences. Proteobacteria, Crenarchaeota and Firmicutes were the most abundant phyla in the transgenic and nontransgenic wheat rhizosphere. Further comparison of different taxonomic units at the genus level showed similar distribution in transgenic and nontransgenic wheat rhizospheres. Conclusion We conclude that the AVP1 gene in transgenic wheat has no apparent adverse effects on the soil environment and different bacterial communities. However, the bacterial community depends on several other factors, not only genetic composition of the host plants. Significance of the study The present research supports introduction and cultivation of transgenic plants in agricultural systems without any adverse effects on indigenous bacterial communities and soil ecosystems.

Home potentiometric sensing devices can real-time monitor personal health status and are widely used in the prevention and management of related diseases. However, variations in the composition and the pH of the sample matrix tend to change the basic potential and response slope of some potentiometric sensors, thus affecting detection reliability. Therefore, this work uses the detection of urea in urine as a model to improve reliability of the potentiometric sensor in home detection. Au@urease nanoparticles were synthesized as the sensing material to improve the stability of the urease-based potentiometric sensor. Meanwhile, a multicalibrated urea potential (MCUP) sensing array was designed, which consists of a urea electrode group, a pH electrode group, and a reference channel. The urea electrode group and the pH electrode group contain respectively a sensing channel and a calibration channel. The basic potential of sensing channels can be calibrated through the corresponding calibration channels. Moreover, the pH electrode group can not only measure the pH values of the samples but also calibrate the response slope of the urea electrode group through the calibration coefficient, thus improving the reliability of home detection. Consequently, the potentiometric sensing array based on the enzyme reaction can be applied in body fluids with a wide pH range.

The interaction between polyamines and phosphate species is found in a wide range of biological and abiotic systems, yielding crucial consequences that range from the formation of supramolecular colloids to structure determination. In this work, the occurrence of phosphate-amino interactions is evidenced from changes in the electronic response of graphene field effect transistors (gFETs). First, the surface of the transistors is modified with poly(allylamine), and the effect of phosphate binding on the transfer characteristics is interpreted in terms of its impact on the surface charge density. The electronic response of the polyamine-functionalized gFETs is shown to be sensitive to the presence of different phosphate anions, such as orthophosphate, adenosine triphosphate, and tripolyphosphate, and a simple binding model is developed to explain the dependence of the shift of the Dirac point potential on the phosphate species concentration. Afterward, the impact of phosphate-amino interactions on the immobilization of enzymes to polyamine-modified graphene surfaces is investigated, and a decrease in the amount of anchored enzyme as the phosphate concentration increases is found. Finally, multilayer polyamine-urease biosensors are fabricated while increasing the phosphate concentration in the enzyme solution, and the sensing properties of the gFETs toward urea are evaluated. It is found that the presence of simple phosphate anions alters the nanoarchitecture of the polyelectrolyte-urease assemblies, with direct implications on urea sensing.

Frequent and improper use of herbicides disrupts a plant's metabolism, causing oxidative stress that degrades crop quality. However, few studies have examined the inhibitory effects of herbicides on plant growth and defense mechanisms in terms of their impact on soil quality and crop rhizosphere. Therefore, the current study investigated the detrimental impacts of six typical and multilevel herbicides on the microbial community and signal molecules in the soil as well as on the levels of hormones and secondary metabolites in wheat seedlings. Interestingly, bensulfuron-methyl, terbutylazine (TBA), and 2,4-D butylate significantly induced oxidative damage while reducing the number of phytohormones (salicylic acid and jasmonic acid) and secondary metabolites (tricin, quercetin, and caffeic acid) in the roots and leaves compared with the controls, isoproturon, fenoxaprop

The cultivated soils in several semi-arid areas have very low organic matter due to climatic constraints that limit primary crop yield. Conservation tillage systems, outlined here as no tillage, no tillage with straw return and straw incorporation into the field, have been accepted as capable systems that preserve soil’s resources and sustain soil productivity. However, in semi-arid climates, there is presently no knowledge about the influence of different conservation tillage techniques on soil’s physical, chemical and biological properties at different soil depths in spring wheat fields and only little information about spring wheat yield in these management systems. Therefore, the present study was carried out with the objective of examining the impact of conservation tillage systems on soil properties (physical, chemical and biological) and spring wheat yield. The three conservation tillage treatments consisted of no tillage system (NT), wheat stubble return with no tillage (NTS) and straw incorporation with conventional tillage (CTS), as well as one conventional tillage (CT) control treatment, which were evaluated under randomized complete block design with three replications. The three conservation tillage treatments were compared with the conventional tillage control. Conservation tillage significantly increased the bulk density, gravimetric water content, water storage, hydraulic conductivity and soil aggregates and decreased the pore space and soil temperature compared to CT; however, no significant difference was found in the case of field capacity. Soil chemical properties in the 0–40 cm soil layer increased with conservation tillage compared to CT. Conservation tillage also notably increased the soil microbial counts, urease, alkaline phosphatase, invertase, cellulase and catalase activities relative to CT. Microbial biomasses (carbon and nitrogen) and wheat yield significantly elevated under conservation tillage compared to CT. Therefore, conservation tillage could significantly improve soil properties and maintain wheat yield for the research zone.

Two urease operons were identified in Klebsiella pneumoniae CG43, ure-1 and ure-2. This study investigates whether a differential regulation of the expression of ure-1 and ure-2 exists and how urease activity influences the acid stress response and expression of type 1 and type 3 fimbriae.The ureA1 and ureA2 gene specific deletion mutants were constructed. Promoter activity was assessed using a LacZ reporter system. The sensitivity to acid stress was determined by assessing the survival after pH 2.5 treatment. The influence on type 1 and type 3 fimbriae expression was assessed using western blotting and mannose-sensitive yeast agglutination and biofilm formation assay, respectively.Bacterial growth analysis in mM9-U or modified Stuart broth revealed that ure-1 was the principal urease system, and ure-2 had a negative effect on ure-1 activity. Deletion of the fur or nac gene had no apparent effect on the activity of Pure-1 is the primary expression system in K. pneumoniae CG43, while ure-2 is active in the absence of hns. Impairment of urease activity increases the sensitivity to acid stress, and the accumulation of urea induces the expression of type 1 fimbriae but represses type 3 fimbriae expression.

Bioscaffolds having electrically conducting polymers (CPs) have become increasingly relevant in tissue engineering (TE) because of their ability to regulate conductivity and promote biological function. With this in mind, the current study shows a conducting polyaniline nanofibers (PNFs) dispersed chitosan (Ch) nanocomposites scaffold with a simple one-step surface functionalization approach using glutaraldehyde for potential neural regeneration applications. According to the findings, 4 wt % PNFs dispersion in Ch matrix is an optimal concentration for achieving desirable biological functions while maintaining required physicochemical properties as evidenced by SEM, XRD, current-voltage (

Strobilanthes glutinosus (family: Acanthaceae) is one of the important medicinal plants and the current research work was carried out to assess the phytochemical, biological, and in-silico evaluations of different solvent extracts of S. glutinosus. The phytochemical composition was assessed by determining qualitative phytochemical testing, total bioactive contents, and GC-MS analysis. For biological evaluation, antioxidant (DPPH and FRAP), antibacterial, and enzyme inhibition (urease) potential were determined. The methanol extract was found to contain the highest total phenolic (247.85 mg GAE/g extract), and flavonoid content (71.91 mg QAE/g extract), which can be correlated to the observed higher antioxidant potential of this extract. On the contrary, the n-hexane extract presented maximum anti-urease activity with IC50 value of 0.244 mg/ml, whereas, in the case of antibacterial assays, a dose-dependent activity was observed. Similarly, the GC-MS investigation of methanol extract and n-hexane fraction revealed the tentative identification of several important classes of secondary metabolites. Furthermore, the main compounds as identified by GC-MS were further studied for in-silico molecular docking studies in order to highlight any interactions between the compounds identified and the urease enzyme. Overall, the present investigation highlighted the studied plant extracts to be considered further for the isolation of bioactive compounds for the pharmaceutical and food industry.

Blocking the catalytic activity of urease has been shown to have a key role in different diseases as well as in different agricultural applications. A vast array of molecules have been tested against ureases of different species, but the clinical translation of these compounds has been limited due to challenges of potency, chemical and metabolic stability as well as promiscuity against other proteins. The design and development of new compounds greatly benefit from insights from previously tested compounds; however, no large-scale studies surveying the urease inhibitors' chemical space exist that can provide an overview of developed compounds to data. Therefore, given the increasing interest in developing new compounds for this target, we carried out a comprehensive analysis of the activity landscape published so far. To do so, we assembled and curated a data set of compounds tested against urease. To the best of our knowledge, this is the largest data set of urease inhibitors to date, composed of 3200 compounds of diverse structures. We characterized the data set in terms of chemical space coverage, molecular scaffolds, distribution with respect to physicochemical properties, as well as temporal trends of drug development. Through these analyses, we highlighted different substructures and functional groups responsible for distinct activity and inactivity against ureases. Furthermore, activity cliffs were assessed, and the chemical space of urease inhibitors was compared to DrugBank. Finally, we extracted meaningful patterns associated with activity using a decision tree algorithm. Overall, this study provides a critical overview of urease inhibitor research carried out in the last few decades and enabled finding underlying SAR patterns such as under-reported chemical functional groups that contribute to the overall activity. With this work, we propose different rules and practical implications that can guide the design or selection of novel compounds to be screened as well as lead optimization.

Hepatic encephalopathy (HE) is the neuropsychiatric complication of liver cirrhosis (LC). The influence of gut microbiota on HE pathogenesis has been suggested but not precisely elucidated. Here, we investigate how the gut microbial profile changed in patients with HE to clarify the functional gut microbial species associated with HE. We focused on their responses to rifaximin (RFX), a nonabsorbable antibiotic used in HE therapy. Feces samples were collected from patients with decompensated LC (all HE), patients with compensated LC, and healthy controls, and fecal gut microbial profiles were compared using 16S ribosomal RNA gene amplicon and metagenomic sequencing. The linear discriminant analysis effect size was used to identify specific species. Urease-positive Streptococcus salivarius, which can produce ammonia, was identified as the most significantly abundant gut microbiota in the HE group, and its ability to elevate the levels of blood ammonia as well as brain glutamine was experimentally verified in mice. Urease-negative Ruminococcus gnavus was also identified as a significantly abundant species in patients with RFX-nonresponsive HE after RFX administration. Interestingly, R. gnavus enhanced urease activity of recombinant urease itself, implying that R. gnavus could amplify ammonia production of surrounding urease-positive microbiota. Furthermore, the sensitivity of S. salivarius and R. gnavus to RFX depended on conjugated secondary bile acid levels, suggesting a therapeutic potential of the combined use of secondary bile acid levels with RFX for enhancing the efficacy of RFX. This study identified specific gut bacterial species abundant in patients with HE and verified their functions linked to HE pathophysiology. Targeting these bacteria could be a potentially effective strategy to treat HE.

Portable hemodialysis has the potential to improve health outcomes and quality of life for patients with kidney failure at reduced costs. Urea removal, required for dialysate regeneration, is a central function of any existing/potential portable dialysis device. Urea in the spent dialysate coexists with non-urea uremic toxins, nutrients, and electrolytes, all of which will interfere with the urea removal efficiency, regardless of whether the underlying urea removal mechanism is based on urease conversion, direct urea adsorption, or oxidation. The aim of the current review is to identify the amount of the most prevalent chemicals being removed during a single dialysis session and evaluate the potential benefits of an urea-selective membrane for portable dialysis.We have performed a literature search using Web of Science and PubMed databases to find available articles reporting (or be able to calculate from blood plasma concentration) 5 mg of individually quantified solutes removed during thrice-weekly hemodialysis sessions. If multiple reports of the same solute were available, the reported values were averaged, and the geometric mean of standard deviations was taken. Further critical literature analysis of reported dialysate regeneration methods was performed using Web of Science and PubMed databases.On average, 46.0 g uremic retention solutes are removed in a single conventional dialysis session, out of which urea is only 23.6 g. For both urease- and sorbent-based urea removal mechanisms, amino acids, with 7.7 g removal per session, could potentially interfere with urea removal efficiency. Additionally for the oxidation-based urea removal system, plentiful nutrients such as glucose (24.0 g) will interfere with urea removal by competition. Using a nanofiltration membrane between dialysate and oxidation unit with a molecular weight cutoff (MWCO) of ~200 Da, 67.6 g of non-electrolyte species will be removed in a single dialysis session, out of which 44.0 g are non-urea molecules. If the membrane MWCO is further decreased to 120 Da, the mass of non-electrolyte non-urea species will drop to 9.3 g. Reverse osmosis membranes have been shown to be both effective at blocking the transport of non-urea species (creatinine for example with ~90% rejection ratio), and permissive for urea transport (~20% rejection ratio), making them a promising urea selective membrane to increase the efficiency of the oxidative urea removal system.Compiled are quantified solute removal amounts greater than 5 mg per session during conventional hemodialysis treatments, to act as a guide for portable dialysis system design. Analysis shows that multiple chemical species in the dialysate interfere with all proposed portable urea removal systems. This suggests the need for an additional protective dialysate loop coupled to urea removal system and an urea-selective membrane.

Urease catalyzes the hydrolysis of urea to form ammonia and carbamate, inducing an overall pH increase that affects both human health and agriculture. Inhibition, mutagenesis, and kinetic studies have provided insights into its enzymatic role, but there have been debates on the substrate binding mode as well as the reaction mechanism. In the present study, we report quatum mechanics-only (QM-only) and quantum mechanics/molecular mechanics molecular dynamics (QM/MM MD) calculations on urease that mainly investigate the binding mode of urea and the mechanism of the urease-catalyzed hydrolysis reaction. Comparison between the experimental data and our QM(GFN2-xTB)/MM metadynamics results demonstrates that urea hydrolysis via a complex with bidentate-bound urea is much more favorable than via that with monodentate-bound urea for both nucleophilic attack and the subsequent proton transfer steps. We also indicate that the bidentate coordination of urea fits the active site with a closed conformation of the mobile flap and can facilitate the stabilization of transition states and intermediates by forming multiple hydrogen bonds with certain active site residues.

Background Ruminants can utilize urea as a dietary nitrogen source owing to their ability to recycle urea-N back to the rumen where numerous ureolytic bacteria hydrolyze urea into ammonia, which is used by numerous bacteria as their nitrogen source. Rumen ureolytic bacteria are the key microbes making ruminants the only type of animals independent of pre-formed amino acids for survival, thus having attracted much research interest. Sequencing-based studies have helped gain new insights into ruminal ureolytic bacterial diversity, but only a limited number of ureolytic bacteria have been isolated into pure cultures or studied, hindering the understanding of ureolytic bacteria with respect to their metabolism, physiology, and ecology, all of which are required to effectively improve urea-N utilization efficiency. Results We established and used an integrated approach, which include urease gene (ureC) guided enrichment plus in situ agarose microsphere embedding and cultivation under rumen-simulating conditions, to isolate ureolytic bacteria from the rumen microbiome. We optimized the dilutions of the rumen microbiome during the enrichment, single-cell embedding, and then in situ cultivation of microsphere-embedded bacteria using dialysis bags placed in rumen fluid. Metabonomic analysis revealed that the dialysis bags had a fermentation profile very similar to the simulated rumen fermentation. In total, we isolated 404 unique strains of bacteria, of which 52 strains were selected for genomic sequencing. Genomic analyses revealed that 28 strains, which were classified into 12 species, contained urease genes. All these ureolytic bacteria represent new species ever identified in the rumen and represented the most abundant ureolytic species. Compared to all the previously isolated ruminal ureolytic species combined, the newly isolated ureolytic bacteria increased the number of genotypically and phenotypically characterized ureolytic species by 34.38% and 45.83%, respectively. These isolated strains have unique genes compared to the known ureolytic strains of the same species indicating their new metabolic functions, especially in energy and nitrogen metabolism. All the ureolytic species were ubiquitous in the rumen of six different species of ruminants and were correlated to dietary urea metabolism in the rumen and milk protein production. We discovered five different organizations of urease gene clusters among the new isolates, and they had varied approaches to hydrolyze urea. The key amino acid residues of the UreC protein that potentially plays critical regulatory roles in urease activation were also identified. Conclusions We established an integrated methodology for the efficient isolation of ureolytic bacteria, which expanded the biological resource of crucial ureolytic bacteria from the rumen. These isolates play a vital role in the incorporation of dietary nitrogen into bacterial biomass and hence contribute to ruminant growth and productivity. Moreover, this methodology can enable efficient isolation and cultivation of other bacteria of interest in the environment and help bridge the knowledge gap between genotypes and phenotypes of uncultured bacteria.

Urease is an enzyme that has a key role in nitrogen metabolism in plant germination. Grains are produced more amount of urease than other plants. Glycine max is also called soya bean, a yearly vegetable of the pea family Fabaceae and it’s an eatable seed. Glycine max is mostly used as protein rich legume only, but it has a lot of medical and industrial applications too. Glycine max is used as a source of urease. The goal of this task is to study the kinetic activities of urease enzyme in Glycine max. The first enzyme was extracted from soya beans and partially purified. The enzyme activity was determined in both crude and partially purified using standard procedure. Further, enzyme kinetics (effect of temperature, pH, and substrate concentration) was studied using urease enzyme extracted from soya beans. The purification fold was 1.8 with a yield of 75%. The factors accustomed for its action was pH 8, temperature 50°C, Vmax and Km in Michaelis-Menten plot is 100 units and 8x10-4 moles/litre and LB Plot is 0.25units and 20x10-4 moles/litre.

Soil bacteria can produce urease, which catalyzes the hydrolysis of urea to ammonia (NH3) and carbamate. A variety of urease inhibitors have been proposed to reduce NH3 volatilization by interfering with the urease activity. We report a quantum mechanics/molecular mechanics molecular dynamics (QM/MM MD) study on the mechanism employed for the inhibition of urease by three representative competitive inhibitors; namely, acetohydroxamic acid (AHA), hydroxyurea (HU), and N-(n-butyl)phosphorictriamide (NBPTO). The possible connections between the structural and thermodynamical properties and the experimentally observed inhibition efficiency were evaluated and characterized. We demonstrate that the binding affinity decreases in the order NBPTO >> AHA > HU in terms of the computed activation and reaction free energies. This trend also indicates that NBPTO shows the highest inhibitory activity and the lowest IC50 value of 2.1 nM, followed by AHA (42 μM) and HU (100 μM). It was also found that the X=O moiety (X = carbon or phosphorous) plays a crucial role in the inhibitor binding process. These findings not only elucidate why the potent urease inhibitors are effective but also have implications for the design of new inhibitors.

Helicobacter pylori urease remains a validated drug target for the eradication of pervasive chronic stomach infection that leads to severe human health diseases such as gastritis and stomach cancer. The increased failure of current treatment protocols because of resistance to broadband antibiotics, severe side effects and low compliance underscore the need for a targeted eradication therapy. Therefore, in the present research, we have developed a new series of acetylphenol-based acyl thioureas that can potentially provide a new template for drug candidates to inhibit urease enzyme. Newly synthesized compounds 7a-j were evaluated for urease inhibitory strength using thiourea as a positive control. In vitro inhibitory results revealed that all the tested compounds were significantly potent than the standard drug. The most active lead 7f competitively inhibited the enzyme and displayed an IC

The present article describes the design, synthesis, in vitro urease inhibition, and in silico molecular docking studies of a novel series of nitrothiazolacetamide conjugated to different thioquinazolinones. Fourteen nitrothiazolacetamide bearing thioquinazolinones derivatives (8a-n) were synthesized through the reaction of isatoic anhydride with different amine, followed by reaction with carbon disulfide and KOH in ethanol. The intermediates were then converted into final products by treating them with 2-chloro-N-(5-nitrothiazol-2-yl)acetamide in DMF. All derivatives were then characterized through different spectroscopic techniques (1H, 13C-NMR, MS, and FTIR). In vitro screening of these molecules against urease demonstrated the potent urease inhibitory potential of derivatives with IC50 values ranging between 2.22 ± 0.09 and 8.43 ± 0.61 μM when compared with the standard thiourea (IC50 = 22.50 ± 0.44 μM). Compound 8h as the most potent derivative exhibited an uncompetitive inhibition pattern against urease in the kinetic study. The high anti-ureolytic activity of 8h was confirmed against two urease-positive microorganisms. According to molecular docking study, 8h exhibited several hydrophobic interactions with Lys10, Leu11, Met44, Ala47, Ala85, Phe87, and Pro88 residues plus two hydrogen bound interactions with Thr86. According to the in silico assessment, the ADME-Toxicity and drug-likeness profile of synthesized compounds were in the acceptable range.

Klebsiella pneumoniae is an opportunistic pathogen that mostly affects those with weakened immune systems. Urease is a vital enzyme that can hydrolyze urea to ammonia and carbon dioxide as a source of nitrogen for growth. Urease is also a K. pneumoniae virulence factor that enables survival of the bacterium under nutrient-limiting conditions. UreF, an important nickel-binding urease accessory protein, is involved in the insertion of Ni2+ into the active site of urease. Here, the crystal structure of UreF from K. pneumoniae (KpUreF) is reported. Functional data show that KpUreF forms a stable dimer in solution. These results may provide a starting point for the design of urease inhibitors.

Hibernation is a mammalian strategy that uses metabolic plasticity to reduce energy demands and enable long-term fasting. Fasting mitigates winter food scarcity but eliminates dietary nitrogen, jeopardizing body protein balance. Here, we reveal gut microbiome–mediated urea nitrogen recycling in hibernating thirteen-lined ground squirrels ( Ictidomys tridecemlineatus ). Ureolytic gut microbes incorporate urea nitrogen into metabolites that are absorbed by the host, with the nitrogen reincorporated into the squirrel’s protein pool. Urea nitrogen recycling is greatest after prolonged fasting in late winter, when urea transporter abundance in gut tissue and urease gene abundance in the microbiome are highest. These results reveal a functional role for the gut microbiome during hibernation and suggest mechanisms by which urea nitrogen recycling may contribute to protein balance in other monogastric animals.

BACKGROUND: Benzimidazole derivatives are widely used to design and synthesize novel bioactive compounds. There are several approved benzimidazole-based drugs on the market. OBJECTIVES: In this study, we aimed to design and synthesize a series of novel benzimidazole derivatives 8a-n that are urease inhibitors. METHODS: All 8a-n were synthesized in a multistep. To determine the urease inhibitory effect of 8a-n, the urease inhibition kit was used. The cytotoxicity assay of 8a-n was determined using MTT method. Molecular modelling was determined using autodock software. RESULTS: All 8a-n were synthesized in high yield, and their structures were determined using (1)H-NMR, (13)C-NMR, MS, and elemental analyses. In compared to thiourea and hydroxyurea as standards (IC50: 22 and 100 µM, respectively), all 8a-n had stronger urease inhibition activity (IC50: 3.36—10.81 µM). With an IC50 value of 3.36 µM, 8e had the best enzyme inhibitory activity. On two evaluated cell lines, the MTT cytotoxicity experiment revealed that all 8a-n have IC50 values greater than 50 µM. Finally, a docking investigation revealed a plausible way of interaction between the 8e and 8d and the enzyme's active site's key residues. CONCLUSION: The synthesized benzimidazole derivatives exhibit high activity, suggesting that further research on this family of compounds would be beneficial to finding a potent urease inhibitor. GRAPHICAL ABSTRACT: [Image: see text]

Nickel is an essential element as the cofactor in the enzyme urease, and pecan (Carya illinoinensis (Wangenh.) K. Koch) is known to suffer from commercially important nickel deficiency manifested in “mouse-ear” disease. Foliar application of nickel has been shown to increase foliar nickel concentrations and foliar urease activity and to cure the nickel deficiency syndrome. However, there is currently no detailed knowledge on the uptake pathways of nickel into pecan leaves and subsequent internal redistribution of nickel after foliar application. In this study, we cultivated pecan seedlings for a period of 6 months after germination (growing to 250–350 mm tall with mature compound leaves) under low nickel availability in hydroponics solutions. The solution was purified to < 0.001 mg L−1 of nickel, and plants displayed severe “mouse-ear” deficiency symptoms. Half of the plants were then treated with a foliar nickel spray (100 mg L−1 nickel), and leaves were analysed using instrumental micro-X-ray fluorescence (µXRF) analysis, and total leaf nickel concentrations and urease activities were determined. The results show that nickel is rapidly taken up in the leaf and distributed into the vascular bundles. Application of nickel leads to a major increase in urease activity as well as in leaf nickel concentrations, and young emerging growth no longer display deficiency symptoms. The uptake pathway of nickel following foliar application is via the main vein into the secondary veins towards other tissues.

The capture and detection of cells expressing a breast-cancer related membrane protein, namely a BT474 cell line expressing HER2, is demonstrated using ion-sensitive field effect transistors (ISFETs). BT474 cells were exposed to anti-HER2 antibodies and urease-conjugated secondary antibodies to induce chemical signal amplification by adding urea.

5-Pentylresorcinol is a type of the group of resorcinol compounds that is resorcinol in that has hydrogen atom at position 5 is replaced by a pentyl group. It has a role as a lichen metabolite. This compound showed excellent to good inhibitory activities against studied these enzymes with IC

Urease is a metallo-protein in which two nickel (Ni) atoms are present at the active site. It is found in all the organisms such as, bacteria, fungi, plants, and in algae. Urease enzymes are also involved in catalyzing the hydrolysis of urea into CO2 and NH3. 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. Current research work aimed to purify the three di-naphthodiospyrols namely; 5,4 -dihydroxy-1-methoxy-6,6 -dimethyl7,3-binaphthyl-1,4,5,8-tetraone (1), 5,8 -dihydroxy-5-methoxy-6,6-dimethyl-7,3-binaphthyl-1,4,1,4 -tetraone (2) and 8,5,8-trihydroxy-6,6-dimethyl-7,3-binaphthyl-1,4,1,4-tetraone (3) from the chloroform fraction of Diospyros lotus roots. The pure constituents (1-3) were evaluated for their urease inhibitory activity. Compounds (1-3) exhibited potent activity with IC50 value of 28.27 ± 1.68, 20.57 ± 2.00, 27.12 ± 2.45 µM respectively, when compared with standard thiourea (IC50 = 21.23 ± 0.12 µM). The pure isolated compounds (1-3) were also subjected to in silico studies to know their binding pattern with enzyme. The binding orientation and interactions with the important residues of urease enzyme revealed that the three compounds inactivate the enzyme activity by interacting with Ni bi-center as well as with the tailpiece residues.

Syzygium cumini L. (Jamun) is a Pakistani indigenous plant, which exhibits various diseases biological activities including antidiabetic, antiulcer, hepatoprotective, and even diuretic. The present work was carried out to provide a scientific justification to its use in folk medicine. In the current research work, the crude methanol extract and subsequent fractions of S. cumini fruits were subjected to phytochemical studies, along with urease, α-glucosidase, and phosphodiesterase inhibition profiling. Results showed that the plant is a rich source of various classes of compounds such as alkaloids, steroids, flavonoids, carbohydrates, phenols, glycosides, saponins, and tannins. In addition, results indicated that the crude extract and fractions significantly inhibit the aforementioned enzymes at tested concentrations. The observed urease inhibitory activity (IC50 values) of methanol, ethyl acetate, n-butanol, and chloroform were 10.17 ± 1.00, 7.09 ± 2.00, 8.32 ± 1.76, and 12.23 ± 1.09 µg, respectively. Similarly, the crude methanol extract, ethyl acetate, chloroform, and n-butanol factions exhibited significant α-glucosidase inhibitory potential with IC50 values of 129.98 ± 1.23, 702.74 ± 1.65, 430.21 ± 1.98, and 650.11 ± 1 0.00 µg, respectively, as compared to the standard. On the other hand, the ethyl acetate and n-butanol factions showed excellent phosphodiesterase inhibitory effect with IC50 values of 270.77 ± 1.98 and 87.09 µg, respectively. The antagonistic effect of these samples is attributed to the presence of different phytochemicals. Moreover, the inhibition of these enzymes provided a sound scientific backup to the mentioned folklores.

The aim of the present study was focused on experimental analysis for medicinal use of Micromeria biflora Benth. The plant was collected and subjected to extraction and fractionation; the chloroform fraction resulted in the isolation of a new constituent salicylalazine, using preparative HPLC. The Chemical structure of salicylalazine was confirmed through NMR and high-resolution mass spectrometry. Salicylalazine was evaluated (in vitro) against various biological targets such as urease, phosphodiesterase-1, tyrosinase, and anti-glycation studies. Furthermore, the binding orientation and interaction pattern of salicylalazine with crucial amino acid residues of the respective targets were used to explore the mechanism of enzymes inhibition. Results indicated that salicylalazine caused potent urease inhibition with an IC50 value of 12.4 ± 1.10 µM, in comparison of standard thiourea (IC50 = 21.0 ± 0.21 µM). The compound exhibited excellent inhibition potential against tyrosinase (89.4%), phosphodiesterase-1 (94.7%) compared to the standards kojic acid (86.3%) and EDTA (86.4%), respectively. Besides, salicylalazine possessed good anti-glycation activity with % inhibition of 86% and IC50 value of 248.7 ± 2.09 µM, compared to the standard Rutin (96%, IC50 value of 295 ± 3.14). Thus, it is concluded that salicylalazine, the active constituent Micromeria biflora Benth, exhibited remarkable in vitro inhibition of urease, phosphodiesterase-1, tyrosinase, and anti-glycation.

The plants of the Erythrina genus possess tremendous pharmacological properties and thus are utilized in traditional medicines owing to their bioactivities. In the present study, methanolic extract (EsM) of flowers of Erythrina suberosa Roxb. and its fractions (n-hexane (EsH), chloroform (EsC) and aqueous (EsW) parts) were tested for preliminary phytochemical analysis, antioxidant and urease inhibition activities. The EsM extract was found to be most active for antioxidant activity, whereas the EsH extract showed the highest anti-urease potential with an inhibition value of 62.9 % (at a concentration of 100 µg/ml), while the other extracts were least active. The EsH extract being most active against urease enzyme, was further subjected to gas chromatography-mass spectrometry (GC-MS) analysis, which revealed the tentative presence of 18 secondary metabolites of various classes. Furthermore, the in-silico studies of the major compounds as detected in EsH extract by GC-MS analysis were performed to correlate the potential interaction of compounds with the active site of the enzyme. The selected compounds were docked against the urease enzyme, and their affinities were compared. Binding affinity data and interaction patterns of all the studied phytochemicals indicated that these compounds could inhibit urease enzyme synergistically and can be further studied to prevent ulcer and related problems. It is, therefore concluded that E. suberosa flowers possess interesting antioxidant and anti-urease potential and thus could further be adopted for industrial and biopharmaceutical applications.

Objective: The present study was conducted to assess the effect of urease inhibitor (hydroquinone [HQ]) and nitrification inhibitor (dicyandiamide [DCD]) on nitrogen (N) use efficiency of pig slurry for perennial ryegrass regrowth yield and its environmental impacts.Methods: A micro-plot experiment was conducted using pig slurry-urea 15N treated with HQ and/or DCD and applied at a rate of 200 kg N/ha. The flows of N derived from the pig slurry urea to herbage regrowth and soils as well as soil N mineralization were estimated by tracing pig slurry-urea 15N, and the N losses via ammonia (NH3), nitrous oxide (N2O) emission, and nitrate (NO3–) leaching were quantified for a 56 d regrowth of perennial ryegrass (Lolium perenne) sward.Results: Herbage dry matter at the final regrowth at 56 d was significantly higher in the HQ and/or DCD applied plots, with a 24.5% to 42.2% increase in 15N recovery by herbage compared with the control. Significant increases in soil 15N recovery were also observed in the plots applied with the inhibitors, accompanied by the increased N content converted to soil inorganic N (NH4+ +NO3–) (17.3% to 28.8% higher than that of the control). The estimated loss, which was not accounted for in the herbage-soil system, was lower in the plots applied with the inhibitors (25.6% on average) than that of control (38.0%). Positive effects of urease and/or nitrification inhibitors on reducing N losses to the environment were observed at the final regrowth (56 d), at which cumulative NH3 emission was reduced by 26.8% (on average 3 inhibitor treatments), N2O emission by 50.2% and NO3– leaching by 10.6% compared to those of the control.Conclusion: The proper application of urease and nitrification inhibitors would be an efficient strategy to improve the N use efficiency of pig slurry while mitigating hazardous environmental impacts.

Microbial-induced calcite precipitation is a promising technology to solve the problem of cracks in soil concrete. The most intensively investigated microorganisms are urease-producing bacteria. Lysinibacillus that is used as urease-producing bacteria in concrete repair has rarely been reported. In this study, Lysinibacillus boronitolerans with a high urease activity was isolated from soil samples. This strain is salt- and alkali-tolerance, and at pH 13, can grow to ~OD(600) 2.0 after 24 h. At a salt concentration of 6%, the strain can still grow to ~OD(600) 1.0 after 24 h. The feasibility of using this strain in self-healing concrete was explored. The data showed that cracks within ~0.6 mm could be repaired naturally with hydration when spores and substrates were added to the concrete in an appropriate proportion. Moreover, the number and morphology of CaCO(3) crystals that were produced by bacteria can be influenced by the concrete environment. An efficiency method to elucidate the process of microbial-induced calcium carbonate crystal formation was established with Particle Track G400. This study provides a template for future studies on the theory of mineralization based on microorganisms. IMPORTANCE The formation of calcium carbonate crystals in concrete by urease-producing bacteria is not understood fully. In this study, a Lysinibacillus boronitolerans strain with a high urease activity was isolated and used to analyze the counts and sizes of the crystals and the relationship with time. The data showed that the number of crystal particles increases exponentially in a short period with sufficient substrate, after which the crystals grow, precipitate or break. In concrete, the rate-limiting steps of calcium carbonate crystal accumulation are spore germination and urease production. These results provided data support for the rational design of urease-producing bacteria in concrete repair.

Brazil is an important peanut producer, but despite its high production, there still needs to be an inoculant for the peanut crop. In addition, the use of microorganisms that promote plant growth (PGPM) is not common, and this crop is highly dependent on chemical fertilizers. An excellent alternative to reduce the use of fertilizers and chemical inputs in peanut crops while reducing the production cost and environmental impact is the use of PGPM. The objective of this study was to evaluate the effects of Azospirillum brasilense, Bacillus subtilis, Bradyrhizobium japonicum, and Trichoderma harzianum as single inoculants and co-inoculants on the growth promotion and productivity of peanuts in greenhouse and field conditions. In the greenhouse, the experiment was conducted with 12 treatments with six repetitions. In the field conditions, the experiment was conducted with five treatments with four repetitions. Both experiments were conducted in randomized blocks. In general, all the microorganisms evaluated in the present study promoted increases in root dry mass, shoot dry mass, phosphorus concentrations, and plant height in the greenhouse and under field conditions compared with the control. Interestingly, the mixtures of microorganisms inoculated in peanut plants did not promote greater plant growth and development compared with inoculations of the microorganisms separately. Specifically, in the field, the highest productivity was found for the inoculation of B. japonicum alone. The PGPM evaluated in the present study for peanut crops generally promoted some increases in productivity in greenhouse and field conditions.

Objective: The purposes of this multi-center study were to evaluate the rate of infection stones and to evaluate the urine cultures of patients with infection stones. Materials: Charts of adulpatients with urinary stones were reviewed and data on stone analyses and urine cultures were collected. Results: In total, 1204 renal stone formers (RSFs) from 10 countries were included (776 males, 428 females). Fifty-six patients (4.6%) had struvite stones. The highest frequency of struvite stones was observed in India (23%) and Pakistan (18%). Lower rates were reported in Canada (2%), China (3%), Argentina (3%), Iraq (3%), Italy (3.5%) and Poland (3%), and intermediate rates in Egypt (5.5%) and Bulgaria (5.4%). Urine cultures were retrieved from 508 patients. Patients with struvite stones had a positive culture in 64.3% of the samples and patients with other stones, in 26.7%. In struvite stones, the most common isolates were Escherichia coli (27.7%) and Proteus spp. (27.7%), followed by Klebsiella spp. (16.7%); in other types of stone, it was Escherichia coli (47.6%), followed by Gram-positive bacteria (14.0%) Conclusions: The struvite stone composition was associated with a urinary infection, although an infection was not demonstrable with a conventional midstream urine culture in about 30%.

Numerous applications of silver nanoparticles (AgNPs), as well as the toxic effects of these particles on soil organisms and microorganisms, raise the question of how reasonable the entry of these nanoparticles into the environment is. Studying the behavior of these nanoparticles with soil organisms and also their effect on soil microorganisms may be the first step to finding out the answer. Structural and form differences in these nanoparticles for use in different conditions can change their behavior. The surface of these nanoparticles is covered with diverse coatings with differing surface charges affecting their fate in soil environments. Naturally, studying this aspect is essential to better understand how these particles impact the environment. In the present study, urease and dehydrogenase enzymes were used as soil health indicators to evaluate the effect of AgNPs and silver nitrate (AgNO3). In order to investigate the effect of surface charge, concentration, and exposure time, three concentration levels (5, 25, 125 mg/kg soil), three different types of charged coatings (citrate (Cit), polyvinylpyrrolidone (PVP) and polyethyleneimine (PEI)) were added to the soil as a treatment and the activities of dehydrogenase (as an indicator of overall microbial activity) and urease (indicator of nitrogen cycle) were measured at three times (1 h, 1 day and 90 days) after soil contamination. The results showed that with increasing the concentration of AgNO3 and AgNPs, the amount of dehydrogenase and urease activity decreased significantly. In the case of urease enzyme, nanoparticles with PEI coating (positive charge) had the greatest effect on reducing activity. In the case of dehydrogenase the opposite was true, and nanoparticles with Cit coating (negative charged) showed a greater inhibitory effect. With increasing incubation time, the amount of enzymatic activity of both types of enzymes showed less decrease, so that the greatest decrease in activity was in the first hour, then in the first day, and finally in 90 days. By comparing silver nitrate and nanoparticles it was found that the effect of AgNPs on enzymatic activity was greater than silver nitrate.

Coumarins, a heterocyclic benzo-α-pyrones and naturally occurring ring structure that possess significant pharmacological properties, have attracted the attention of researchers and medicinal chemists to reveal the suitability of both natural and synthetic coumarins as drugs. Many compounds have been synthesized utilizing the basic coumarin structure. The diverse synthetic methods resulted in the synthesis of important coumarin derivatives that offer a wide range of biological properties as antimicrobial, anticancer, anti-inflammatory, antioxidant, antidiabetic and antidepressant that make them potential drug candidates. With a particular interest in ulcers, coumarins have shown potential inhibition against urease enzyme. In recent years, scientists have emphasized the anti-urease activity of coumarins due to their low toxicity. The aim of this review is to compile data from recent research about anti-urease activities of coumarins and structure-activity relationship studies of the coumarin ring structure. Investigation of different structural substitutions in coumarin rings may help researchers to design new compounds with strong and effective anti- urease abilities.

This study tried to examine the feasibility of enzyme-induced calcium carbonate precipitation (EICP) for CO2 leakage prevention in a subsurface condition. For this, the effects of 1) concentrations of urease enzyme and reactants (urea and CaCl2), 2) initial pH (3–9), and 3) temperature (30–50 °C) on the precipitation of calcium carbonate were tested in the batch experiments. In addition, the core-plugging experiment was conducted to test the potential application of EICP to a porous medium with high permeability. The batch experiments showed that the 0.25 M urea was completely hydrolyzed by urease (above 1000 U/l). However, 0.4 M and 0.5 M urea were not completely decomposed because of the insufficient quantity of urease. Our result also showed that urea hydrolysis was not observed at pH 3, while the efficiency of calcite precipitation was not affected in the pH range of 5 to 9. Temperature also affected the hydrolysis of urea. The efficiency of calcite precipitation increased with increasing temperature from 30 °C to 50 °C. In addition, the result of the core-plugging experiment showed that the permeability of the sandstone core decrease by approximately 42% due to the precipitation of calcite in the pores. From our results, this study suggested that EICP can be a potential for CO2 leakage prevention from a storage reservoir within the pH and temperature ranges of this study.

Urease is a metalloenzyme that catalyzes the hydrolysis of urea into ammonia and carbon dioxide, which has a negative impact on human health and agriculture. In this study, the inactivation of jack bean urease by nitidine chloride (NC) was investigated to elucidate the inhibitory effect, kinetics, and underlying mechanism of action. The results showed that NC acted as a concentration- and time-dependent inhibitor with an IC50 value of 33.2 ± 4.8 μM and exhibited a similar inhibitory effect to acetohydroxamic acid (IC50 = 31.7 ± 5.8 μM). Further kinetic analysis demonstrated that NC was a slow-binding and non-competitive inhibitor for urease. Thiol-blocking reagents (dithiothreitol, glutathione, and l-cysteine) significantly retarded urease inactivation, while Ni2+ competitive inhibitors (boric acid and sodium fluoride) synergetically suppressed urease with NC, suggesting that the active site sulfhydryl groups were possibly obligatory for NC blocking urease. Molecular docking simulation further argued its inhibition mechanism. Additionally, NC-induced deactivation of urease was verified to be reversible since the inactivated enzyme could be reactivated by glutathione. Taking together, NC was a non-competitive inhibitor targeting the thiol group at the active site of urease with characteristics of concentration dependence, reversibility, and slow binding, serving as a promising novel urease suppressant.

Context Enhanced-efficiency nitrogen (N) fertilisers (EEFs) can reduce N loss, but productivity and environmental benefits vary. A field experiment on rainfed ryegrass dominant pastures in southern Australia examined the effect of EEFs combined with reduced N rate on agronomic N efficiency (AE) (additional biomass per unit N applied) and apparent NUE (ApNUE) (additional plant N uptake per unit N applied) relative to urea. Methods EEFs examined were granular urea coated with (i) urease inhibitor N-(n-butyl)thiophosphoric triamide (NBPT), (ii) nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) or (iii) polymer coating (PCU). Nitrogen was applied five times over 9 months at 0–84 kg N ha−1 per application. Key results AE varied with season from –0.5 to 22.3 kg DM kg N−1 in late (dry conditions) and early spring (ideal conditions), respectively. AE of PCU was significantly lower than urea for the first harvest due to slow N release. Using DMPP led to higher AE than equivalent urea rates in August (at 34 and 50 kg N ha−1) and early October (34 kg N ha−1). At the lowest rate (17 kg N ha−1), NBPT generally led to higher AE than at higher N rates. Using NBPT at 17 kg N ha−1 led to higher AE than urea at the same rate in July, August and February. The ApNUE ranged from 3.6% (summer) to 68% (early spring), and decreased with increasing N rate. Using DMPP did not significantly change cumulative ApNUE (entire experiment) (34%) due to limited leaching and denitrifying conditions. Cumulative ApNUE was lowest with PCU (23%) due to initial slow N release. Conclusion Seasonal variations in pasture responses to fertiliser N affected the efficiency outcomes from using EEFs. Implications Benefits in ApNUE and AE from using EEFs rely on their seasonal strategic use combined with reduced N inputs. The initial slow release of N from the PCU could be overcome by strategies such as combining the PCU with uncoated urea, to improve ApNUE.

Reliable diagnostics are a major challenge for the detection and treatment of Helicobacter pylori (H. pylori) infection. Currently at the forefront are non-invasive urea breath test (UBT) and stool antigen test (SAT). Polymerase chain reaction (PCR) is not endorsed due to nonspecific primers and the threat of false-positives. The specificity of DNA amplification can be achieved by nested PCR (NPCR), which involves two rounds of PCR. If the primers are properly designed for the variable regions of the 16S rRNA gene, it is not difficult to develop an NPCR assay for the unambiguous identification of H. pylori. Elaborate NPCR for a 454 bp amplicon was validated on 81 clinical biopsy, stool, and saliva samples, each from the same individuals, and compared with available H. pylori assays, namely histology, rapid urease test, SAT, and 13C-UBT. The assay was much more sensitive than simple PCR, and it was equally sensitive in biopsy samples as the 13C-UBT test, which is considered the gold standard. In addition, it is sufficiently specific because sequencing of the PCR products exclusively confirmed the presence of H. pylori-specific DNA. However, due to the threshold and lower abundance, the sensitivity was much lower in amplifications from stool or saliva. Reliable detection in saliva also complicates the ability of H. pylori to survive in the oral cavity aside from and independent of the stomach. The reason for the lower sensitivity in stool is DNA degradation; therefore, a new NPCR assay was developed to obtain a shorter 148 bp 16S rRNA amplicon. The assay was validated on stool samples from 208 gastroenterological patients and compared to SAT results. Surprisingly, this NPCR revealed the presence of H. pylori in twice the number of samples as SAT, indicating that many patients are misdiagnosed, not treated by antibiotics, and their problems are interpreted as chronic. Thus, it is unclear how to properly diagnose H. pylori in practice. In the first approach, SAT or UBT is sufficient. If samples are negative, the 148 bp amplicon NPCR assay should be performed. If problems persist, patients should not be considered negative, but due to threshold H. pylori abundance, they should be periodically tested. The advantage of NPCR over UBT is that it can be used universally, including questionable samples taken from patients with achlorhydria, receiving proton pump inhibitors, antibiotics, bismuth compound, intestinal metaplasia, or gastric ulcer bleeding.

Ureases are moonlighting proteins displaying non-catalytic properties, including platelet activation, antifungal and entomotoxic effects. The structure-activity mapping of these properties is poorly developed. Proteus mirabilis urease (PMU) consists of three subunits, PmUreα, PmUreβ and PmUreγ, in an (αβγ)3 organization. In order to study the structure-activity relationships of PMU we obtained the recombinant subunits of this urease and evaluated their biological activities. The holo-urease promoted platelet aggregation, and toxicity in fungal and insect models. Similar to Jaburetox, a plant urease-derived polypeptide, PmUreβ showed the highest toxicity against yeasts and insects, and activated human platelets. PmUreγ and PmUreα presented insecticidal action upon injection. In addition, only PmUreγ and PmUreβ promote hemocytes aggregation. Bioinformatics analyses revealed gene/segment duplication and evolutionary divergence among ureases. Our findings show that PmUreβ (and probably its counterparts in other ureases) carries most of the non-enzymatic activities of these proteins.

Our objective was to determine the within and between laboratory performance of an enzymatic spectrophotometric method for milk urea nitrogen (MUN) determination. This method first uses urease to hydrolyze urea into ammonia and carbon dioxide. Next, ammonia (as ammonium ions) reacts with 2-oxoglutarate, in the presence of reduced nicotinamide-adenine dinucleotide phosphate (NADPH) and the enzyme glutamate dehydrogenase (GlDH), to form l-glutamic acid, water, and NADP+. The change in light absorption at 340 nm due to the conversion of NADPH to NADP+ is stoichiometrically a function of the MUN content of a milk sample. The relative within (RSDr) and between (RSDR) laboratory method performance values for the MUN enzymatic spectrophotometric method were 0.57% and 0.85%, respectively, when testing individual farm milks. The spectrophotometric MUN method demonstrated better within and between laboratory performance than the International Dairy Federation differential pH MUN method with a much lower RSDr (0.57 vs. 1.40%) and RSDR (0.85 vs. 4.64%). The spectrophotometric MUN method also had similar method performance statistics as other AOAC International official validated chemical methods for primary milk component determinations, with the average of all RSDr and RSDR values being

Background: Thiourea is a classical urease inhibitor which is usually used as a positive control, and many N,N'-disubstituted thioureas have been determined as urease inhibitors. However, due to steric hindrance, N,N'-disubstituted thiourea motif could not bind urease as thiourea. On the contrary, N-monosubstituted thiourea with a tiny thiourea motif could theoretically bind into the active pocket as thiourea. Objective: A series of N-monosubstituted aroylthioureas were designed and synthesized for evaluation as urease inhibitors. Methods: Urease inhibition was determined by the indophenol method and IC50 values were calculated using computerized linear regression analysis of quantal log dose-probit functions. The kinetic parameters were estimated via surface plasmon resonance (SPR) and by nonlinear regression analysis based on the mixed type inhibition model derived from Michaelis-Menten kinetics. Results: Compounds b2, b11, and b19 reversibly inhibited urease with a mixed mechanism, and showed excellent potency against both cell-free urease and urease in the intact cell, with IC50 values being 90- to 450-fold and 5- to 50-fold lower than the positive control acetohydroxamic acid, respectively. The most potent compound b11 showed an IC50 value of 0.060 ± 0.004μM against cell-free urease, which bound to urea binding site with a very low KD value (0.420±0.003nM) and a very long residence time (6.7 min). Compound b11 was also demonstrated to have very low cytotoxicity to mammalian cells. Conclusion: The results revealed that N-monosubstituted aroylthioureas bound to the active site of urease as expected, and represent a new class of urease inhibitors for the development of potential therapeutics against infections caused by urease-containing pathogens.

Urease is a biocatalyst that serves to hydrolyze urea into ammonia and carbon dioxide. Since it is an imported product, the price of urea is still high. Urease can be found in grains. One of the grains that has not been explored for its urease content is durian (Durio zibethinus L.) seeds. This study aims to determine the effect of germination time on the activity of urease from durian seeds and its characteristics including the effect of pH, incubation temperature, enzymatic reaction time, addition of EDTA and metals, and storage time on the activity of urease from durian seeds. The first step of this study was seed germination which was carried out in the dark for 0, 3, 5, 7, and 9 days. Durian seed sprouts were extracted by mashing them using a mortar and pestle. They were then homogenized using a stirrer and centrifuged in a cold state. The crude urease extract obtained was then tested for its activity using the Nessler method. The acquired data was tested statistically using ANOVA. The results showed that the activity of urease from durian seeds was optimum at 3-day germination time, pH 7, incubation temperature at 30 °C, and 15-minute enzymatic reaction time with an activity of 163.6 U/mL. Urease is a metalloenzyme with its inhibitor being the Cu2+ and Na+ metal ions and its activator being Ba2+ metal ion. Tukey's test analysis showed that the effect of urease storage time at 4 °C resulted in a stable urease activity for 8 days while at room temperature it decreased its activity significantly to 72.8%.

A series of Zn(II) complexes, supported with N-substituted phenylethanamine derivatives, [LnZnCl2] (where Ln = LA ((R)-1-phenyl-N-(thiophene-2-ylmethyl)ethanamine; LB (R)-N-(5-meyhylthiophene-2-yl)methyl-1-phenylethanamine; LC ((R)-N-(furan-2-ylmeththyl)-1-phenylethanamine and LD (R)-N-((5-methylfuran-2-yl)methyl)-1-phenylethanamine) were synthesized and characterized. The urease inhibitory activities of these complexes were determined against selected urease inhibitors where [LBZnCl2] was found to be the most prominent inhibitor of Jack bean urease (J. B. urease) (IC50 = 10.39±0.78 μM), whereas the activity of Bacillus pasteurii urease (B. P. urease) was predominantly inhibited by [LAZnCl2] (IC50 = 8.68±0.7 μM). Additionally, MOE-Dock program was used to affirm the probable binding modes of these complexes into the crystal structure of J. B. urease which certainly verified the inhibitory mechanism of these novel complexes. KEY WORDS: Zn(II) complexes, (R)-Phenylethanamine, Urease inhibition, Molecular docking Bull. Chem. Soc. Ethiop. 2021, 35(2), 301-314. DOI: https://dx.doi.org/10.4314/bcse.v35i2.7

One of the latest developments in biocementation is the use of one-phase-low-pH MICP or EICP method as a more effective and efficient alternative to the traditional two-phase method for the treatment of sandy soil. However, the one-phase-low-pH method has its own limitation. The pH of the solution has to be adjusted before every treatment. In this study, a modified one-phase-low-pH MICP or EICP method is proposed in order to simplify the treatment procedure to improve the efficiency of biotreatment in real constructions. In this method, the low-pH bacteria or urease solution is only used together with the cementation solution (i.e., CaCl2 and urea) for the first treatment and for the subsequent treatment, only cementation solution is used. The test results show that using the modified one-phase-low-pH MICP method with a bacterial solution of a volume ratio of 0.75 is comparable to that using the original one-phase-low-pH method, and 80% of the calcium conversion efficiency can be maintained for up to 5 treatments. However, the modified one-phase-low-pH EICP method may only be used for the first 2 or 3 treatments due to the relatively poor durability of urease enzyme in inducing calcium carbonate during the subsequent injections of cementation solution. Ministry of Education (MOE) Singapore Maritime Institute (SMI) The authors would like to thank the financial supports provided through Grant No. MOE2015-T2-2-142 by the Ministry of Education, Singapore, and the Grant No. SMI-2018-MA02 by the Singapore Maritime Institute which are gratefully acknowledged.

Goal: on the basis of the veterinary and laboratory diagnostics department with a testing laboratory, surveillance studies of fodder of vegetable origin from different manufacturers were carried out for the following indicators: urease activity, mass content of soluble protein. An experiment on the activity of urease in full-fat soybean feed was also performed. To assess the quality of heat treatment of soybeans and products of its processing, to analyze the stability of the parameter of urease in fodder soybeans. Methods. These studies were performed in accordance with GOST 13979.9-69; GOST 13979.3-68. Results. As a result of statistical processing, it was revealed that over the past five years, urease activity was above the maximum permissible value in 33 % of feed samples. In some samples of soybeans, this indicator was exceeded by 2.6 times, in the experimental sample of soybeans – by 5.8 times. It was also experimentally confirmed that this indicator is a stable parameter. Additionally, studies of the cumulative mass content of soluble proteins were conducted in these samples. It was found that in 13 % of soybean samples and its processed products, the result of soluble protein was in the range of 68.20–74.50 %, which indicates excessive heat treatment of this raw material. Based on the results of the research conducted, it was found that this feedstock did not always meet the stated requirements. In this regard, the conduct of these studies is necessary for further control of the technological process. Scientific novelty. Currently, the issue of the quality of fodder of vegetable origin and soybean-processed products remains relevant. Full-fat soybean, soybean extracted meal, soybean expeller meal are increasingly used for the preparation of animal feed for farm animals and poultry. In this regard, it became necessary to control the quality and safety of this feedstock.

Honey has long been used as a food and has been reported to have potential health benefits. In this work, total phenol content, colour and antioxidant and hepatoprotective activities of honey samples of different floral origins from the State of Hidalgo, Mexico were explored using in vitro assays. Hepatoprotective activity was measured by inhibitition of β-glucuronidase; gastroprotective activity was determined by inhibition of urease; antioxidant activity was evaluated by 2,2'-Azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and 2, 2-diphenyl-1-picrylhydrazyl (DPPH) methods. All the parameters showed significant differences (p

As ureases são enzimas que catalisam a hidrólise da ureia, formando amônia, gás carbônico e água. A hidrólise da ureia desempenha um papel importante no ciclo do nitrogênio, pois fornece esse elemento para o crescimento de microrganismos e plantas. Entretanto, a ação excessiva da urease leva à vários problemas em organismos vivos e, também, pode causar danos ambientais e econômicos. Os inibidores de urease podem ser uma boa alternativa para o tratamento de doenças causadas por microrganismos patogênicos dependentes da enzima urease. A curcumina, um produto natural obtido da Curcuma longa, é conhecida no Brasil como açafrão, e possui uma estrutura com capacidade de complexar metais, tornando-a um potencial inibidor de metaloproteínas, como a urease. Por esse motivo, nesse trabalho foi avaliado o potencial de interação da curcumina e de onze análogos com o sítio ativo da enzima urease utilizando os programas Autodock e Mopac2016. Os resultados mostraram que nove compostos possuem maior interação com o sítio ativo da enzima urease quando comparados com o substrato ureia, apresentando energias de ligação entre -7,24 e -5,12 kcal/mol, enquanto a ureia apresentou energia de ligação igual a -4,10 kcal/mol. O produto natural curcumina ficou na quinta posição, apresentando energia de ligação de -6,21 kcal/mol, demonstrando grande potencial para o uso como inibidor da enzima urease.

The use of a biological dust suppressant for the prevention of mine dust was explored. A biological dust suppressant was prepared with Bacillus pasteurii, CaCl2 and urea as raw materials. The results show that the surface tension of the bacterial solution and the CaCl2-urea solution was 32.517 and 32.595 mN/m, respectively, which had a good effect on wetting coal dust. When the concentration of CaCl2-urea solution was 0.6 mol/L, the yield of mineralized products was the highest. In addition, the urease activity was the strongest. According to the wind resistance test, when the volume ratio of the bacterial solution to the CaCl2-urea solution was 1:1 and the CaCl2-urea solution was 0.6 mol/L, the dust suppression effect was the best. The above results show that MICP is a mine dust control technology with strong development prospects.

The popularized application of annual ryegrass—maize rotation (ARMR) in southern China has been proposed to fully utilize the farmlands and to increase forage yield and quality. Herein, one growth cycle of ARMR was conducted and soil bacteria were analyzed by 16S rRNA sequencing for control (CK), after the preceding crop (monoculture, or mixed sowing of annual ryegrass and oat) and the successive crop (maize). Our results indicated that the α-diversity of soil bacteria was changed in the ARMR system, which was related to the activity of urease and available phosphatase. The mixed sowing of annual ryegrass and oat in preceding crop could improve the yield and quality, while it was accompanied by unbalanced soil community. With the increased sowing proportion of oat to annual ryegrass, the soil pH increased while the soil available phosphatase decreased. The ARMR system was found to benefit the soil microenvironment by increasing the beneficial soil bacteria and enzyme activity or decreasing the harmful soil bacteria. Considering the soil bacteria α-diversity index and physicochemical properties comprehensively, the recommended sowing regime is the mixed sowing of M2 (22.5 kg·hm−2 annual ryegrass with 75 kg·hm−2 oat).

Construction of optical pH sensor as a new platform optical urea biosensor based on polyelectrolyte complex (PEC) pectin-chitosan membrane and total phenolic (anthocyanin) of Tapak Dara flower (Catharanthus roseus) has been successfully carried out. The anthocyanin was extracted by a maceration method for 72 hours using methanol, and a total extract yield was 21.56% or 1.803 mg/L. Flavonoid and phenol tests showed positive results indicated by the formation of red and black colours. The anthocyanins showed maximum absorption at 578 nm for phosphate buffer and 575 nm for tris HCl buffer solution. The sensor fabrication was performed using a mixture of pectin and chitosan solutions with a ratio of 3:7. The anthocyanin was mixed into the solution with various concentrations. The sensor has an optimum sensitivity at the anthocyanin concentration of 0.05 mg/L (phosphate buffer) in the pH range of 7.0-9.5 and 0.025 mg/L (Tris HCl buffer) with a narrower pH range of 6.0-7.5. This sensor produced higher sensitivity, a wider linear range, and good linearity when it was exposed in 0.03M PBS. Reproducibility test with a relative standard deviation percentage (% RSD) was 9.20. The sensor showed a stable response after 5 minutes exposed to PBS solution, and it can be used to measure pH within the 20th day. The optimized optical pH sensor has been successfully developed as a urea optical biosensor by immobilizing urease on its surface. The biosensor showed a linear response in a series of 10-1-10-10 M urea concentrations and has good linearity.