Chlorogenic acid, caffeic acid and luteolin from dandelion as urease inhibitors: insights into the molecular interactions and inhibition mechanism.

BACKGROUND: Dandelion contains hundreds of active compounds capable of inhibiting urease activity, but the individual compounds have not yet been fully identified, and their effects and underlying mechanisms are not clear. The present study aimed to screen the urease inhibition active compounds of dandelion by urease inhibitory activity evaluation HPLC-tandem mass spectrometry analysis, their mechanism of urease inhibition by polyphenols was explored using enzyme kinetic studies via Lineweaver-Burk plots. Other investigations included isothermal titration calorimetry and surface plasmon resonance sensing, fluorescence quenching experiments, and single ligand molecular docking and two-ligand simultaneous docking techniques. RESULTS: The results indicated that the ethyl acetate fraction of dandelion flower exhibited the greatest inhibition (lowest IC50 0.184 ± 0.007 mg mL-1). Chlorogenic acid, caffeic acid and luteolin could be effective urease inhibitors that acted in a non-competitive inhibition manner. Individually, chlorogenic acid could not only fast bind to urease, but also dissociate rapidly, whereas luteolin might interact with urease with the weakest affinity. The chlorogenic acid-caffeic acid combination exhibited an additive effect in urease inhibition. However, the chlorogenic acid-luteolin and caffeic acid-luteolin combinations exhibited antagonistic effects, with the caffeic acid-luteolin combination showing greater antagonism. CONCLUSION: The present study reveals that chlorogenic acid, caffeic acid and luteolin are major bioactive compounds for urease inhibition, indicating the molecular mechanisms. The antagonistic effects were observed between luteolin and chlorogenic acid/caffeic acid, and the interactions of the catalytic site and flap may account for the antagonistic effects. © 2024 Society of Chemical Industry.

Differential expression of urease genes and ureolytic activity of uropathogenic Escherichia coli and Pseudomonas aeruginosa isolates in different nutritional conditions.

Uropathogens have adaptation strategies to survive in the host urinary tract by efficiently utilizing and tolerating the urinary metabolites. Many uropathogens harbour the enzyme urease for the breakdown of urea and the enzymatic breakdown of urea increases the pH and facilitate the struvite crystallization. In this study, the differential urease activity of uropathogenic Escherichia coli and Pseudomonas aeruginosa strains was investigated under different nutritional conditions. The experiments included measurement of growth, pH, urease activity, NH4-N generation and urease gene (ureC) expression among the bacterial strains under different conditions. Further, the implications of urea breakdown on the struvite crystallization in vitro and biofilm formation were also assessed. The study included urease positive isolates and for comparison urease negative isolates were included. Compared to the urease negative strains the urease positive strains formed higher biofilms and motility. The urease positive P. aeruginosa showed significantly higher (p < 0.01) pH and urease activity (A557-A630) compared to E. coli under experimental conditions. Further, supplementation of glucose to the growth media significantly increased the urease activity in P. aeruginosa and in contrast, it was significantly lower in E. coli. The expression profile of urease gene (ureC) was significantly higher (p < 0.001) in P. aeruginosa compared to E. coli and was consistent with the biochemical results of the urease activity under the nutritional conditions. The differential urease activity under two nutritional conditions influenced the biogenic struvite crystallization. It correlated with the urease activity showing higher crystallization rate in P. aeruginosa compared to E. coli. The results highlight the differential urease activity in two common uropathogens under different nutritional conditions that may have significant role on the regulation of virulence, pathogenicity and in the kidney stone disease.

Gut symbiotic bacteria are involved in nitrogen recycling in the tephritid fruit fly Bactrocera dorsalis.

BACKGROUND: Nitrogen is considered the most limiting nutrient element for herbivorous insects. To alleviate nitrogen limitation, insects have evolved various symbiotically mediated strategies that enable them to colonize nitrogen-poor habitats or exploit nitrogen-poor diets. In frugivorous tephritid larvae developing in fruit pulp under nitrogen stress, it remains largely unknown how nitrogen is obtained and larval development is completed. RESULTS: In this study, we used metagenomics and metatranscriptomics sequencing technologies as well as in vitro verification tests to uncover the mechanism underlying the nitrogen exploitation in the larvae of Bactrocera dorsalis. Our results showed that nitrogenous waste recycling (NWR) could be successfully driven by symbiotic bacteria, including Enterobacterales, Lactobacillales, Orbales, Pseudomonadales, Flavobacteriales, and Bacteroidales. In this process, urea hydrolysis in the larval gut was mainly mediated by Morganella morganii and Klebsiella oxytoca. In addition, core bacteria mediated essential amino acid (arginine excluded) biosynthesis by ammonium assimilation and transamination. CONCLUSIONS: Symbiotic bacteria contribute to nitrogen transformation in the larvae of B. dorsalis in fruit pulp. Our findings suggest that the pattern of NWR is more likely to be applied by B. dorsalis, and M. morganii, K. oxytoca, and other urease-positive strains play vital roles in hydrolysing nitrogenous waste and providing metabolizable nitrogen for B. dorsalis.

Bioactive Polyketides from the Natural Complex of the Sea Urchin-Associated Fungi Penicillium sajarovii KMM 4718 and Aspergillus protuberus KMM 4747.

The marine-derived fungal strains KMM 4718 and KMM 4747 isolated from sea urchin Scaphechinus mirabilis as a natural fungal complex were identified as Penicillium sajarovii and Aspergillus protuberus based on Internal Transcribed Spacer (ITS), partial ß-tubulin (BenA), and calmodulin (CaM) molecular markers as well as an ribosomal polymerase two, subunit two (RPB2) region for KMM 4747. From the ethyl acetate extract of the co-culture, two new polyketides, sajaroketides A (1) and B (2), together with (2'S)-7-hydroxy-2-(2'-hydroxypropyl)-5-methylchromone (3), altechromone A (4), norlichexanthone (5), griseoxanthone C (6), 1,3,5,6-tetrahydroxy-8-methylxanthone (7), griseofulvin (8), 6-O-desmethylgriseofulvin (9), dechlorogriseofulvin (10), and 5,6-dihydro-4-methyl-2H-pyran-2-one (11) were identified. The structures of the compounds were elucidated using spectroscopic analyses. The absolute configurations of the chiral centers of sajaroketides A and B were determined using time-dependent density functional theory (TDDFT)-based calculations of the Electronic Circular Dichroism (ECD) spectra. The inhibitory effects of these compounds on urease activity and the growth of Staphylococcus aureus, Escherichia coli, and Candida albicans were observed. Sajaroketide A, altechromone A, and griseofulvin showed significant cardioprotective effects in an in vitro model of S. aureus-induced infectious myocarditis.

Substituting urea with biogas slurry and hydrothermal carbonization aqueous product could decrease NH3 volatilization and increase soil DOM in wheat growth cycle.

Biogas slurry (BS) and hydrothermal carbonization aqueous products (HAP), which are rich in nitrogen (N) and dissolved organic matter (DOM), can be used as organic fertilizer to substitute inorganic N fertilizer. To evaluate the effects of co-application of BS and HAP on the ammonia (NH3) volatilization and soil DOM content in wheat growth season, we compared six treatments that substituting 50%, 75%, and 100% of urea-N with BS plus HAP at low (L) or high (H) ratio, named BCL50, BCL75, BCL100, BCH50, BCH75, BCH100, respectively. Meanwhile, urea alone treatment was set as the control (CKU). The results showed that both BCL and BCH treatments significantly mitigate the NH3 volatilizations by 9.1%-45.6% in comparison with CKU (P < 0.05), whose effects were correlated with soil NH4+-N content. In addition, the decrease in soil urease activity contributed to the lower NH3 volatilization following application of BS plus HAP. Notably, BS plus HAP applications increased the microbial byproduct- and humic acid-like substances in soil by 9.9%-74.5% and 100.7%-451.9%, respectively. Consequently, BS and HAP amended treatments significantly increased soil humification index and DOM content by 13.7%-41.2% and 38.4%-158.7%, respectively (P < 0.05). This study suggested that BS and HAP could be co-applied into agricultural soil as a potential alternative of inorganic fertilizer N, which can decrease NH3 loss but increase soil fertility.

A selected bacterial strain for the self-healing process in cementitious specimens without cell immobilization steps.

The use of microorganisms capable of mediating the bioprecipitation process can be an important application in the self-healing processes of cement specimens. Thus, the present study identified and evaluated five Bacillus strains for potential application in the protocol of self-healing via bioprecipitation. Cell growth, enzyme production, and kinetic parameters conditions were evaluated during the fermentation process. Based on the analysis of 16S rDNA in conjunction with biochemical testing, results demonstrate that the strains are either Bacillus cereus or Bacillus thuringiensis. Strategically it was found that the addition of glycerol to fermentative medium was essential to increase the bacterial concentration (≈ 4.2 × 107 cells mL-1) and production of the enzyme urease (≈ 3.623,2 U.mL-1). The addition of this medium after 40 days of fermentation promoted the self-healing of cracks and increased compressive strength in ≈ 14.2% of the cementitious specimens; therefore, increasing the sustainability and engineering properties of cement-based materials.

Biochar and urea co-application regulates nitrogen availability in soil.

Overuse of nitrogenous fertilizers especially urea has been considered a significant source of reactive N causing acute environmental impacts through leaching, volatilization, and N2O gas emission from fertilized crop fields. However, some recent studies have proposed that such environmental losses of N can be ignored by adapting an alternative way of combining nitrogenous fertilizer with pyrolyzed biomass (biochar). Therefore, the effect of co-application of rice-residue biochar (RB) or poultry manure biochar (PB) along with urea on N dynamics was investigated by conducting a 60-day incubation experiment. The results showed that urea led to greater N mineralization (0.2 µg N g-1 soil day-1) due to the easy availability of ammonical-N (NH4+-N) produced from hydrolysis that acted as a substrate for nitrification. Sole application of biochars (RB or PB) or their co-application with urea resulted in 38-45% and 19-28% lower N mineralization than the sole urea amended soil, respectively. The lower N mineralization in sole biochar or biochar plus urea amended soil was most likely caused due to (1) increased C:N ratio of the biochar amended soil, (2) adsorption of NH4+-N by biochar, (3) microbial immobilization of the nitrogen in the amended soil, and (4) lower urease activity in the treatments amended with biochar. Thus, it may be concluded that the co-application of biochar with urea can reduce N losses through moderation of N mineralization and make it available to plants for longer periods.

Biosynthesis of the starch is improved by the supplement of nickel (Ni2+) in duckweed (Landoltia punctata).

Duckweed is a kind of floating aquatic plant and increasing its starch production is favorable for bioenergy. In this study, we found that starch biosynthesis was greatly promoted by the supplement of nickel ion (Ni2+) through the comparison of other different ions. The starch content in duckweed was increased by nearly eightfold when duckweed was treated with 20 µM Ni2+. The analysis of paraffin sections visually found that starch granules were more complete and dark blue in Ni2+ treated duckweed than the control. Quantitative real-time PCR demonstrated that the expressions of starch synthesis-related enzymes were up-regulated in Ni2+ treated duckweed. Further analysis revealed that the accumulation of Ni2+ in duckweed effectively increased the activity of urease, which compensated for the deficiency of certain decrease in biomass and accelerated biosynthesis of the starch. Thus, our results represent another strategy to improve starch production of duckweed.

Chitosan Inhibits Helicobacter pylori Growth and Urease Production and Prevents Its Infection of Human Gastric Carcinoma Cells.

This study investigated the effects of shrimp chitosan with 95% degree of deacetylation (DD95) in combination with clinical antibiotics on the growth and urease production of Helicobacter pylori. The inhibitory effect of DD95 on the adherence of H. pylori to the human intestinal carcinoma cells (TSGH9201) was also investigated. Five strains of H. pylori, including three standard strains and two strains of clinical isolates were used as the test strains. The inhibitory effects of DD95 on growth and urease production of various strains of H. pylori increased with increasing DD95 concentration and decreasing pH values from pH 6.0 to pH 2.0. Urease activity of H. pylori at pH 2.0 in the presence of 4000 µg/mL of DD95 decreased by 37.86% to 46.53%. In the presence of 50 µg/mL antibiotics of amoxicillin, tetracycline, or metronidazole at pH 6.0 and pH 2.0, H. pylori counts were decreased by 1.51-3.19, and 1.47-2.82 Log CFU/mL, respectively. Following the addition of 4000 µg/mL DD95 into the 50 µg/mL antibiotic-containing culture medium with pH 6.0 and pH 2.0, overall H. pylori counts were strongly decreased by 3.67-7.61 and 6.61-6.70 Log CFU/mL, respectively. Further, DD95 could inhibit the adherence of H. pylori on TSGH 9201 cells, as evidenced by fluorescent microscopy and thus may potentially protect against H. pylori infection.

Paper chip-based colorimetric assay for detection of Salmonella typhimurium by combining aptamer-modified Fe3O4@Ag nanoprobes and urease activity inhibition.

A rapid and sensitive colorimetric assay is described for Salmonella typhimurium (S. typhimurium) detection using urea/phenol red impregnated test paper. Aptamer-modified Fe3O4@Ag multifunctional hybrid nanoprobes (apt-Fe3O4@Ag NPs) were used to specifically captured S. typhimurium; the nanoprobes were quickly etched by H2O2 to form Ag+. The generated Ag+ can inhibit the urease-catalyzed hydrolysis reaction of urea to produce NH4+. Consequently, the as-prepared test paper displayed a yellow color. In the presence of S. typhimurium, the target bacteria can cause aggregation of apt-Fe3O4@Ag NPs, and the deposited Ag on the nanoprobe's surface is shielded against H2O2-induced oxidative decomposition leading to reduced Ag+ production. The catalytic activity of urease cannot be inhibited completely by inadequate amount of Ag+. An obvious color change from yellow to pink can be monitored directly using our test paper as a result of increased NH4+. The entire assay procedure could be completed within 1 h. A limit of detection of 48 cfu/mL is achieved with a linear range of 1 × 102 to 1 × 106 cfu/mL. The recoveries of S. typhimurium spiked in pure milk samples were 92.48-94.05%. Graphical abstract Schematic diagram of the proposed colorimetric assay for S. typhimurium detection based on etching of bifunctional apt-Fe3O4@Ag NPs and inhibiting catalytic activity of urease by Ag+. A color change from yellow to pink can be observed and correlated to the concentration of S. typhimurium.

Virescenosides From the Holothurian-Associated Fungus Acremonium Striatisporum Kmm 4401.

Ten new diterpene glycosides virescenosides Z9-Z18 (1-10) together with three known analogues (11-13) and aglycon of virescenoside A (14) were isolated from the marine-derived fungus Acremonium striatisporum KMM 4401. These compounds were obtained by cultivating fungus on wort agar medium with the addition of potassium bromide. Structures of the isolated metabolites were established based on spectroscopic methods. The effects of some isolated glycosides and aglycons 15-18 on urease activity and regulation of Reactive Oxygen Species (ROS) and Nitric Oxide (NO) production in macrophages stimulated with lipopolysaccharide (LPC) were evaluated.

Synthesis, biological activity and structure activity relationship studies of novel conazole analogues via conventional, microwave and ultrasound mediated techniques.

1,2,4-Triazole derivatives containing a piperazine nucleus (4a-d and 10) were prepared starting from 1-(2-methoxyphenyl)piperazine or ethyl 4-(4-amino-2-fluorophenyl)piperazine-1-carboxylate via several steps. The synthesis of fifteen compounds (7a-l and 13a-c), which can be considered as new analogues of azole class antifungals was performed starting from 1,2,4-triazoles (4a-d and 10) via three steps containing the condensation with 2-bromo-1-(4-chlorophenyl)ethanone, reduction of carbonyl group to alcohol and alkylation of OH group, respectively. All the reactions were examined under conventional, ultrasound and microwave irradiation conditions as green chemistry techniques, and optimum conditions were defined. The newly synthesized compounds were screened for their biological potentials including antimicrobial, antioxidant, antiurease and anti α-glucosidase activities and promising results were obtained. The enzyme inhibitory potentials of these compounds were further validated through molecular docking.

Synthesis, in vitro urease inhibitory activity, and molecular docking studies of thiourea and urea derivatives.

The current study deals with the synthesis of urea and thiourea derivatives 1-37 which were characterized by various spectroscopic techniques including FAB-MS, 1H-, and 13C NMR. The synthetic compounds were subjected to urease inhibitory activity and compounds exhibited good to moderate urease inhibitory activity having IC50 values in range of 10.11-69.80 µM. Compound 1 (IC50 = 10.11 ±â€¯0.11 µM) was found to be most active and even better as compared to the standard acetohydroxamic acid (IC50 = 27.0 ±â€¯0.5 µM). A limited structure-activity relationship (SAR) was established and the compounds were also subjected to docking studies to confirm the binding interactions of ligands (compounds) with the active site of enzyme.

Phytochemicals in Helicobacter pylori Infections: What Are We Doing Now?

In this critical review, plant sources used as effective antibacterial agents against Helicobacter pylori infections are carefully described. The main intrinsic bioactive molecules, responsible for the observed effects are also underlined and their corresponding modes of action specifically highlighted. In addition to traditional uses as herbal remedies, in vitro and in vivo studies focusing on plant extracts and isolated bioactive compounds with anti-H. pylori activity are also critically discussed. Lastly, special attention was also given to plant extracts with urease inhibitory effects, with emphasis on involved modes of action.

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

BACKGROUND: 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. METHODS: 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. RESULTS: 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). CONCLUSION: The rapid urease test (RUT) in a micro-plate format can be used as a simple and rapid method to test urease activity in bacterial strains in vitro and as a chair-side method for testing urease activity in site-specific supragingival plaque samples ex vivo.

[Mechanism of anti-Helicobacter pylori urease activity of patchouli alcohol].

To investigate the effect of patchouli alcohol on inhibiting Helicobater pylori urease activity, and its effect on expression levels of related genes, and lay the foundation for further research on the effect of patchouli alcohol on H. pylori colonization and infection. H. pyloriwas cultured and identified by gram staining, rapid urease test (RUT) and PCR method. Then agar dilution method was used to detect the bacterial survival after 1 h intervention by different concentrations of patchouli alcoholin the acidic (pH 5.3) and neutral (pH 7.0) conditions; berthelot method was used to detect urease activity and RT-qPCR method was used to detect the expression changes of ureA, ureB, ureE, ureH, ureI, and nixA related urease genes. The results showed that the survival rate of H. pyloriwas not significantly changed but the urease activity was obviously decreased after intervention by different concentrations of patchouli alcohol; meanwhile, the expression levels of ureA, ureB, ureE, ureH, ureI, and nixA were decreased to different degrees. Therefore, patchouli alcohol could inhibit H. pylori urease activity in both acidic and neutral conditions, and the mechanism may be related to down-regulation of urease gene expression.

[Corynebacterium riegelii as an unusual species separated from female patient with tuberculosis.]

The article describes a clinical case of tuberculosis of of urinary tracts of a female patient with massive discharge of strain Corynebacterium riegelii from urogenital tract. The data of clinical laboratory examination of female patient are analyzed. The characteristics of isolated strain C. riegelii (high degree of isolation rate (106 and higher) expressed urease activity (decomposition of urease during 5 min), presence of hemolytic activity) with consideration for estimation of its antibiotics sensitivity. The etiologic significance of isolated species C. riegelii in development of infection process in urogenital tract is demonstrated.

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

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 associa-tion was found between the lack of cagA and increased urease activity among the isolated strains (P = 0.036). While the greatest sequencevariation 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.

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

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.

Synthesis of novel derivatives of oxindole, their urease inhibition and molecular docking studies.

We synthesized a series of novel 5-24 derivatives of oxindole. The synthesis started from 5-chlorooxindole, which was condensed with methyl 4-carboxybezoate and result in the formation of benzolyester derivatives of oxindole which was then treated with hydrazine hydrate. The oxindole benzoylhydrazide was treated with aryl acetophenones and aldehydes to get target compounds 5-24. The synthesized compounds were evaluated for urease inhibition; the compound 5 (IC50 = 13.00 ± 0.35 µM) and 11 (IC50 = 19.20 ± 0.50 µM) showed potent activity as compared to the standard drug thiourea (IC50 = 21.00 ± 0.01 µM). Other compounds showed moderate to weak activity. All synthetic compounds were characterized by different spectroscopic techniques including (1)H NMR, (13)C NMR, IR and EI MS. The molecular interactions of the active compounds within the binding site of urease enzyme were studied through molecular docking simulations.