scholarly journals Functional Glyco-Nanogels for Multivalent Interaction with Lectins

Molecules ◽  
2019 ◽  
Vol 24 (10) ◽  
pp. 1865 ◽  
Author(s):  
Jo Sing Julia Tang ◽  
Sophia Rosencrantz ◽  
Lucas Tepper ◽  
Sany Chea ◽  
Stefanie Klöpzig ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Lectin Binding ◽  
Host Cells ◽  
Protecting Group ◽  
Reaction Parameters ◽  
Binding Studies ◽  
Huge Number ◽  
Dependent Inhibition ◽  
Tremendous Impact

Interactions between glycans and proteins have tremendous impact in biomolecular interactions. They are important for cell–cell interactions, proliferation and much more. Here, we emphasize the glycan-mediated interactions between pathogens and host cells. Pseudomonas aeruginosa, responsible for a huge number of nosocomial infections, is especially the focus when it comes to glycan-derivatives as pathoblockers. We present a microwave assisted protecting group free synthesis of glycomonomers based on lactose, melibiose and fucose. The monomers were polymerized in a precipitation polymerization in the presence of NiPAm to form crosslinked glyco-nanogels. The influence of reaction parameters like crosslinker type or stabilizer amount was investigated. The gels were characterized in lectin binding studies using model lectins and showed size and composition-dependent inhibition of lectin binding. Due to multivalent presentation of glycans in the gel, the inhibition was clearly stronger than with unmodified saccharides, which was compared after determination of the glycan loading. First studies with Pseudomonas aeruginosa revealed a surprising influence on the secretion of virulence factors. Functional glycogels may be in the future potent alternatives or adjuvants for antibiotic treatment of infections based on glycan interactions between host and pathogen.

Lectin Binding Studies on RNA Tumor Virus-Infected Cells

1975 ◽  
Vol 33 ◽  
pp. 326-327
Author(s):  
D. C. Hixson
Keyword(s):  
Binding Sites ◽  
Lectin Binding ◽  
Culture Conditions ◽  
3T3 Cells ◽  
Binding Studies ◽  
Con A ◽  
Microscopic Studies ◽  
Tumor Virus ◽  
Infected Cells ◽  
Cell Culture Conditions

The abilities of plant lectins to preferentially agglutinate malignant cells and to bind to specific monosaccharide or oligosaccharide sequences of glycoproteins and glycolipids make them a new and important biochemical probe for investigating alterations in plasma membrane structure which may result from malignant transformation. Electron and light microscopic studies have demonstrated clustered binding sites on surfaces of SV40-infected or tryp- sinized 3T3 cells when labeled with concanavalin A (con A). No clustering of con A binding sites was observed in normal 3T3 cells. It has been proposed that topological rearrangement of lectin binding sites into clusters enables con A to agglutinate SV40-infected or trypsinized 3T3 cells (1). However, observations by other investigators have not been consistent with this proposal (2) perhaps due to differences in reagents used, cell culture conditions, or labeling techniques. The present work was undertaken to study the lectin binding properties of normal and RNA tumor virus-infected cells and their associated viruses using lectins and ferritin-conjugated lectins of five different specificities.

scholarly journals Kinetic mechanism of Na+-coupled aspartate transport catalyzed by GltTk

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Gianluca Trinco ◽  
Valentina Arkhipova ◽  
Alisa A. Garaeva ◽  
Cedric A. J. Hutter ◽  
Markus A. Seeger ◽  
...  
Keyword(s):  
Kinetic Mechanism ◽  
Protein Quantification ◽  
Detergent Solution ◽  
Sodium Ions ◽  
Binding Studies ◽  
Equilibrium Binding ◽  
Uptake Rates ◽  
Bona Fide ◽  
Inside Out

AbstractIt is well-established that the secondary active transporters GltTk and GltPh catalyze coupled uptake of aspartate and three sodium ions, but insight in the kinetic mechanism of transport is fragmentary. Here, we systematically measured aspartate uptake rates in proteoliposomes containing purified GltTk, and derived the rate equation for a mechanism in which two sodium ions bind before and another after aspartate. Re-analysis of existing data on GltPh using this equation allowed for determination of the turnover number (0.14 s−1), without the need for error-prone protein quantification. To overcome the complication that purified transporters may adopt right-side-out or inside-out membrane orientations upon reconstitution, thereby confounding the kinetic analysis, we employed a rapid method using synthetic nanobodies to inactivate one population. Oppositely oriented GltTk proteins showed the same transport kinetics, consistent with the use of an identical gating element on both sides of the membrane. Our work underlines the value of bona fide transport experiments to reveal mechanistic features of Na+-aspartate symport that cannot be observed in detergent solution. Combined with previous pre-equilibrium binding studies, a full kinetic mechanism of structurally characterized aspartate transporters of the SLC1A family is now emerging.

scholarly journals Immobilization of Pseudomonas aeruginosa static biomass on eggshell powder for on-line preconcentration and determination of Cr (VI)

2020 ◽  
Vol 18 (1) ◽  
pp. 303-313 ◽  
Author(s):  
Aamir Rasheed ◽  
Tahseen Ghous ◽  
Sumaira Mumtaz ◽  
Muhammad Nadeem Zafar ◽  
Kalsoom Akhter ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Low Cost ◽  
Colorimetric Detection ◽  
Time Flow ◽  
Highly Sensitive ◽  
Glass Column ◽  
On Line ◽  
Preconcentration Time ◽  
Ultra Trace

AbstractIn the present work, a novel continuous flow system (CFS) is developed for the preconcentration and determination of Cr (VI) using Pseudomonas aeruginosa static biomass immobilized onto an effective and low-cost solid support of powdered eggshells. A mini glass column packed with the immobilized biosorbent is incorporated in a CFS for the preconcentration and determination of Cr (VI) from aqueous solutions. The method is based on preconcentration, washing and elution steps followed by colorimetric detection with 1,5-diphenyl carbazide in sulphuric acid. The effects of several variables such as pH, retention time, flow rate, eluent concentration and loaded volume are studied. Under optimal conditions, the CFS method has a linear range between 10 and 100 μg L-1 and a detection limit of 6.25 μg L-1 for the determination of Cr (VI). The sampling frequency is 10 samples per hour with a preconcentration time of 5 mins. Furthermore, after washing with a 0.1 M buffer (pH 3.0), the activity of the biosorbent is regenerated and remained comparable for more than 200 cycles. Scanning electron microscopy reveals a successful immobilization of biomass on eggshells powder and precipitation of Cr (VI) on the bacterial cell surface. The proposed method proves highly sensitive and could be suitable for the determination of Cr (VI) at an ultra-trace level.

Antimicrobial and antibiofilm activities of meropenem loaded-mesoporous silica nanoparticles against carbapenem-resistant Pseudomonas aeruginosa

2021 ◽  
pp. 088532822110038
Author(s):  
Mohammad Yousef Memar ◽  
Mina Yekani ◽  
Hadi Ghanbari ◽  
Edris Nabizadeh ◽  
Sepideh Zununi Vahed ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Mesoporous Silica ◽  
Silica Nanoparticles ◽  
Mesoporous Silica Nanoparticles ◽  
Carbapenem Resistant ◽  
Toxicity In Vitro ◽  
Different Levels

The aims of the present study were the determination of antimicrobial and antibiofilm effects of meropenem-loaded mesoporous silica nanoparticles (MSNs) on carbapenem resistant Pseudomonas aeruginosa ( P. aeruginosa) and cytotoxicity properties in vitro. The meropenem-loaded MSNs had shown antibacterial and biofilm inhibitory activities on all isolates at different levels lower than MICs and BICs of meropenem. The viability of HC-04 cells treated with serial concentrations as MICs and BICs of meropenem-loaded MSNs was 92–100%. According to the obtained results, meropenem-loaded MSNs display the significant antibacterial and antibiofilm effects against carbapenem resistant and biofilm forming P. aeruginosa and low cell toxicity in vitro. Then, the prepared system can be an appropriate option for the delivery of carbapenem for further evaluation in vivo assays.

scholarly journals Bacteriophage-Based Biosensing of Pseudomonas aeruginosa: An Integrated Approach for the Putative Real-Time Detection of Multi-Drug-Resistant Strains

Biosensors ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 124
Author(s):  
Liliam K. Harada ◽  
Waldemar Bonventi Júnior ◽  
Erica C. Silva ◽  
Thais J. Oliveira ◽  
Fernanda C. Moreli ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Bacterial Infections ◽  
Research Effort ◽  
Acquired Resistance ◽  
Integrated Approach ◽  
Healthcare Services ◽  
Host Cells ◽  
Color Changes ◽  
Metabolic Versatility ◽  
The Matrix

During the last decennium, it has become widely accepted that ubiquitous bacterial viruses, or bacteriophages, exert enormous influences on our planet’s biosphere, killing between 4–50% of the daily produced bacteria and constituting the largest genetic diversity pool on our planet. Currently, bacterial infections linked to healthcare services are widespread, which, when associated with the increasing surge of antibiotic-resistant microorganisms, play a major role in patient morbidity and mortality. In this scenario, Pseudomonas aeruginosa alone is responsible for ca. 13–15% of all hospital-acquired infections. The pathogen P. aeruginosa is an opportunistic one, being endowed with metabolic versatility and high (both intrinsic and acquired) resistance to antibiotics. Bacteriophages (or phages) have been recognized as a tool with high potential for the detection of bacterial infections since these metabolically inert entities specifically attach to, and lyse, bacterial host cells, thus, allowing confirmation of the presence of viable cells. In the research effort described herein, three different phages with broad lytic spectrum capable of infecting P. aeruginosa were isolated from environmental sources. The isolated phages were elected on the basis of their ability to form clear and distinctive plaques, which is a hallmark characteristic of virulent phages. Next, their structural and functional stabilization was achieved via entrapment within the matrix of porous alginate, biopolymeric, and bio-reactive, chromogenic hydrogels aiming at their use as sensitive matrices producing both color changes and/or light emissions evolving from a reaction with (released) cytoplasmic moieties, as a bio-detection kit for P. aeruginosa cells. Full physicochemical and biological characterization of the isolated bacteriophages was the subject of a previous research paper.

The synthesis of a carbohydrate-like dihydrooxazine and tetrahydrooxazine as putative inhibitors of glycoside hydrolases: A direct synthesis of isofagomine

2002 ◽  
Vol 80 (8) ◽  
pp. 857-865 ◽  
Author(s):  
Wayne M Best ◽  
James M Macdonald ◽  
Brian W Skelton ◽  
Robert V Stick ◽  
D Matthew G Tilbrook ◽  
...  
Keyword(s):  
Direct Synthesis ◽  
Glycoside Hydrolases ◽  
Crystalline Solid ◽  
Glycosidase Inhibitors ◽  
Protecting Group ◽  
Mild Acid Hydrolysis ◽  
Catalytic Hydrogenolysis ◽  
Palladium On Carbon ◽  
Mild Acid

The treatment of benzyl 2,3-O-isopropylidene-β-L-xylopyranoside with N-hydroxyphthalimide under Mitsunobu conditions, followed by protecting-group interchange, gave benzyl 4-O-[(tert-butoxycarbonyl)amino]-2,3- O-isopropylidene-α-D-arabinoside. Mild acid hydrolysis and catalytic hydrogenolysis afforded 4-O-[(tert-butoxycarbonyl)amino]-D-arabinose that, upon heating in water, gave the dihydrooxazine [(4R,5S,6R)-5,6-dihydro-4,5-dihydroxy-6-hydroxymethyl-4H-1,2-oxazine] as a crystalline solid. A single-crystal structure determination of this solid showed it to exist in the 5H6 conformation. Reduction of the dihydrooxazine gave the tetrahydrooxazine [(4R,5S,6R)-4,5-dihydroxy-6-hydroxymethyl-3,4,5,6-tetrahydro-2H-1,2-oxazine]. The dihydrooxazine was an effective inhibitor of two β-glucosidases (Ki = 27 and 35 µM). Benzyl 2,3-O-isopropylidene-β-L-xylopyranoside, via the derived imidazylate, was converted into a nitrile that, upon reduction and protecting-group manipulations, gave benzyl 4-C-aminomethyl-4-deoxy-α-D-arabinoside. Treatment of this amine with hydrogen and palladium-on-carbon gave isofagomine.Key words: dihydrooxazine, tetrahydrooxazine, isofagomine, iminosugars, glycosidase inhibitors.

scholarly journals Screening of a Library of Oligosaccharides Targeting Lectin LecB of Pseudomonas Aeruginosa and Synthesis of High Affinity Oligoglycoclusters

Molecules ◽  
2018 ◽  
Vol 23 (12) ◽  
pp. 3073 ◽  
Author(s):  
Lucie Dupin ◽  
Mathieu Noël ◽  
Silvère Bonnet ◽  
Albert Meyer ◽  
Thomas Géhin ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Binding Sites ◽  
Biofilm Formation ◽  
Selective Advantage ◽  
Host Cells ◽  
Host Defenses ◽  
Negative Bacterium ◽  
High Affinity ◽  
Structure Relationship ◽  
Relationship Of

The Gram negative bacterium Pseudomonas aeruginosa (PA) is an opportunistic bacterium that causes severe and chronic infection of immune-depressed patients. It has the ability to form a biofilm that gives a selective advantage to the bacteria with respect to antibiotherapy and host defenses. Herein, we have focused on the tetrameric soluble lectin which is involved in bacterium adherence to host cells, biofilm formation, and cytotoxicity. It binds to l-fucose, d-mannose and glycan exposing terminal fucose or mannose. Using a competitive assay on microarray, 156 oligosaccharides and polysaccharides issued from fermentation or from the biomass were screened toward their affinity to LecB. Next, the five best ligands (Lewisa, Lewisb, Lewisx, siayl-Lewisx and 3-fucosyllactose) were derivatized with a propargyl aglycon allowing the synthesis of 25 trivalent, 25 tetravalent and 5 monovalent constructions thanks to copper catalyzed azide alkyne cycloaddition. The 55 clusters were immobilized by DNA Directed immobilization leading to the fabrication of a glycocluster microarray. Their binding to LecB was studied. Multivalency improved the binding to LecB. The binding structure relationship of the clusters is mainly influenced by the carbohydrate residues. Molecular simulations indicated that the simultaneous contact of both binding sites of monomer A and D seems to be energetically possible.

scholarly journals Pseudomonas aeruginosa serotypes and resistance to antibiotics from wound swabs

2015 ◽  
Vol 72 (11) ◽  
pp. 996-1003 ◽  
Author(s):  
Natasa Stankovic-Nedeljkovic ◽  
Branislav Tiodorovic ◽  
Branislava Kocic ◽  
Vojislav Ciric ◽  
Marko Milojkovic ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antibiotic Resistance ◽  
Susceptibility Testing ◽  
Wound Infections ◽  
Common Cause ◽  
Resistance To Antibiotics ◽  
Mucous Membranes ◽  
Common Serotypes ◽  
Antibiotics Susceptibility

Introduction/Aim. Pseudomonas aeruginosa (P. aeruginosa) is the most common cause of wound infections, following the disruption of the skin or mucous membranes integrity. The aim of this study was to analyze of the presence P. aeruginosa in wound swabs, antibiotics susceptibility testing, determination of the minimum inhibitory concentrations (MICs) of antibiotics, testing of the metallo-?-lactamases (MBLs) production, isolates serotyping and analysis of the most common serotypes resistance. Methods. A total of 90 outpatients and 55 intpatients wound swabs were cultivated. Wound swabs were taken from the patients with wound infections symptoms. Antibiotics susceptibility testing was performed to: meropenem, imipenem, piperacillin-tazobactam, ceftazidime, cefepime, amikacin, gentamicin, netilmicin, ofloxacin, ciprofloxacin and colistin (HiMedia). Polyvalent and monovalent antisera for agglutination (Biorad) were used in P. aeruginosa agglutination. Results. P. aeruginosa was isolated from 36.55% wound swabs (36.66% of the inpatients wounds and 36.36% of the outpatients). The analyzed isolates showed the highest degree of sensitivity to colistin (100%) and meropenem (93.44%) and the lowest to cefepime (19.54%). The majority of the inpatients isolates had 12 ?g/mL (28.57%) MIC for piperacillin-tazobactam and 16 ?g/mL (28.57%) for the outpatients. The most common MICs for ciprofloxacin were 0.19 ?g/mL (31.81%) for the nosocomial isolates, and 0.25 ?g/mL (28.57%) for the outpatients? ones. The most common MICs for amikacin of the nosocomial isolates were 6 ?g/ml (40.9%), and for the outpatients ones 4 ?g/mL (33.33%). Five (9.43%) isolates produced MBLs. The most common serotypes were P11 (22.64%), P6 (15.09%) and P1 (11.32%). Conclusion. Neither the increased presence of P. aeruginosa was noticed in wounds swabs, nor the antibiotic resistance in the nosocomial isolates compared to those from outpatients. The analyzed isolates had the higest sensitivity to colistin and meropenem, and the lowest to cefepime.

scholarly journals Quercetin attenuates the production of pro-inflammatory cytokines in H292 human lung epithelial cells infected with Pseudomonas aeruginosa, by modulating ExoS production

2020 ◽  
Author(s):  
Hye In Ahn ◽  
Ji-Won Park ◽  
Hyun-Jae Jang ◽  
Ok-kyoung Kwon ◽  
Jung Hee Kim ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Mrna Level ◽  
Inhibitory Effect ◽  
Lung Epithelial Cells ◽  
Host Cells ◽  
Enzyme Linked Immunosorbent Assay ◽  
Elisa System ◽  
Type Three Secretion System ◽  
Sandwich Type ◽  
Needle Protein

Abstract Background: The type three secretion system (T3SS) is a major virulence system of Pseudomonas aeruginosa (P. aeruginosa). The effector protein Exotoxin S (ExoS) produced by P. aeruginosa is secreted into the host cells via the T3SS. For the purpose of screening the inhibitors with regard to ExoS secretion, we developed the sandwich-type enzyme-linked immunosorbent assay (ELISA) system. From the initial screening, quercetin was selected because it has the prominent effect of ExoS inhibition and also is known to have anti-inflammatory and antioxidant effects on mammalian cells.Results: In this study, we investigated the effects of quercetin on the expression and secretion of ExoS using the ELISA and Western blot analysis methods. The results showed that the secretion of ExoS was significantly decreased by 10, 20uM quercetin. Also, pscF and popD, which are composed of the T3SS needle, are reduced by quercetin at the mRNA level, and we confirmed the inhibitory effect of quercetin on cytokines in P. aeruginosa-infected H292 cells by real-time polymerase chain reaction (PCR). Conclusion: Collectively, quercetin inhibits the secretion of ExoS by reducing both ExoS production and the expression of the needle protein of T3SS. Furthermore, these results suggest that quercetin has the potential to be used as an anti-toxic treatment for the disease caused by P. aeruginosa infection.

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