scholarly journals Impact of Citral and Phloretin, Alone and in Combination, on Major Virulence Traits of Streptococcus pyogenes

Molecules ◽  
2019 ◽  
Vol 24 (23) ◽  
pp. 4237 ◽  
Author(s):  
Mohd Adil ◽  
Mohd Hassan Baig ◽  
H.P. Vasantha Rupasinghe
Keyword(s):  
Quorum Sensing ◽  
Synergistic Effect ◽  
Streptococcus Pyogenes ◽  
Synergistic Effects ◽  
Cell Surface Hydrophobicity ◽  
Free Energy Calculations ◽  
Human Tonsil ◽  
Virulence Traits ◽  
The Individual ◽  
Luxs Protein

Streptococcus pyogenes is well documented as a multi-virulent and exclusively human pathogen. The LuxS-based signaling in these bacteria has a crucial role in causing several infections through pathways that are pathogenic. This study evaluated the individual and synergistic effects of citral and phloretin against S. pyogenes in relation to major virulence traits. The in vitro synergy of citral and phloretin was evaluated by the checkerboard method. The fractional inhibitory concentration (FIC) values were calculated to determine the interactions between the inhibitors. The bacteria’s virulence properties were tested in the presence of the molecules, individually as well as in combination. Molecules’ cytotoxicity was tested using human tonsil epithelial cells. The synergistic effects of the molecules on the expression of biofilm and quorum sensing genes were tested using quantitative real-time polymerase chain reaction (qRT-PCR). The molecules were also tested for their impact on LuxS protein by molecular docking, modeling, and free-energy calculations. When the two molecules were assessed in combination (synergistic effect, FIC Index of 0.5), a stronger growth inhibitory activity was exhibited than the individual molecules. The cell surface hydrophobicity, as well as genes involved in quorum sensing and biofilm formation, showed greater suppression when the molecules were tested in combination. The in silico findings also suggest the inhibitory potential of the two molecules against LuxS protein. The binding orientation and the binding affinity of citral and phloretin well support the notion that there is a synergistic effect of citral and phloretin. The data reveal the combination of citral and phloretin as a potent antibacterial agent to combat the virulence of S. pyogenes.

Etiology, clinical presentation, laboratory diagnostics, pathogenesis of impetigo and treatment methods

2020 ◽  
pp. 64-70
Author(s):  
Anastasiya Laknitskaya
Keyword(s):  
Streptococcus Pyogenes ◽  
Skin Diseases ◽  
Group A Streptococcus ◽  
Antibiotic Sensitivity ◽  
Antioxidant Defense System ◽  
Laboratory Diagnostics ◽  
Treatment Methods ◽  
Group A ◽  
The Individual

Currently, one of the priority medical and social problems is the optimization of treatment methods for pyoderma associated with Streptococcus pyogenes — group A streptococcus (GAS). To date, the proportion of pyoderma, the etiological factor of which is Streptococcus pyogenes, is about 6 % of all skin diseases and is in the range from 17.9 to 43.9 % of all dermatoses. Role of the bacterial factor in the development of streptococcal pyoderma is obvious. Traditional treatment complex includes antibacterial drugs selected individually, taking into account the antibiotic sensitivity of pathognomonic bacteria, and it is not always effective. Currently implemented immunocorrection methods often do not take into account specific immunological features of the disease, the individual, and the fact that the skin performs the function of not only a mechanical barrier, but it is also an immunocompetent organ. Such an approach makes it necessary to conduct additional studies clarifying the role of factors of innate and adaptive immunity, intercellular mediators and antioxidant defense system, that allow to optimize the treatment of this pathology.

Platinum and cobalt intermetallic nanoparticles confined within MIL-101(Cr) for enhanced selective hydrogenation of the carbonyl bond in α,β-unsaturated aldehydes: synergistic effects of electronically modified Pt sites and Lewis acid sites

2021 ◽  
Author(s):  
Muhammad Zahid ◽  
Jiang Li ◽  
Ahmed Ismail ◽  
Francisco Zaera ◽  
Yujun Zhu
Keyword(s):  
Synergistic Effect ◽  
Reduction Method ◽  
Synergistic Effects ◽  
Acid Sites ◽  
Lewis Acid Sites ◽  
Unsaturated Aldehydes ◽  
Uniform Dispersion ◽  
Carbonyl Bond ◽  
Method Show ◽  
Intermetallic Nanoparticles

PtCo/MIL-101(Cr) with high uniform dispersion Pt–Co IMNs synthesized by a polyol reduction method show higher activity for selective catalytic hydrogenation of α,β-unsaturated aldehydes due to the synergistic effect of PtCo and MIL-101(Cr) support.

scholarly journals Identification of New Potential Inhibitors of Quorum Sensing through a Specialized Multi-Level Computational Approach

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2600
Author(s):  
Fábio G. Martins ◽  
André Melo ◽  
Sérgio F. Sousa
Keyword(s):  
Virtual Screening ◽  
Quorum Sensing ◽  
In Silico ◽  
Bacterial Infections ◽  
Extracellular Polymeric Substances ◽  
Free Energy Calculations ◽  
Ligand Docking ◽  
Screening Tests ◽  
Scoring Functions ◽  
Potential Inhibitors

Biofilms are aggregates of microorganisms anchored to a surface and embedded in a self-produced matrix of extracellular polymeric substances and have been associated with 80% of all bacterial infections in humans. Because bacteria in biofilms are less amenable to antibiotic treatment, biofilms have been associated with developing antibiotic resistance, a problem that urges developing new therapeutic options and approaches. Interfering with quorum-sensing (QS), an important process of cell-to-cell communication by bacteria in biofilms is a promising strategy to inhibit biofilm formation and development. Here we describe and apply an in silico computational protocol for identifying novel potential inhibitors of quorum-sensing, using CviR—the quorum-sensing receptor from Chromobacterium violaceum—as a model target. This in silico approach combines protein-ligand docking (with 7 different docking programs/scoring functions), receptor-based virtual screening, molecular dynamic simulations, and free energy calculations. Particular emphasis was dedicated to optimizing the discrimination ability between active/inactive molecules in virtual screening tests using a target-specific training set. Overall, the optimized protocol was used to evaluate 66,461 molecules, including those on the ZINC/FDA-Approved database and to the Mu.Ta.Lig Virtual Chemotheca. Multiple promising compounds were identified, yielding good prospects for future experimental validation and for drug repurposing towards QS inhibition.

Synergistic Effects of 5-Fluorouracil in Combination with Diosmetin in Colorectal Cancer Cells

2021 ◽  
Vol 7 (1) ◽  
pp. 6
Author(s):  
Sareh Kamran ◽  
Ajantha Sinniah ◽  
Mohammed Abdullah Alshawsh
Keyword(s):  
Colorectal Cancer ◽  
Flow Cytometry ◽  
Synergistic Effect ◽  
Cancer Cells ◽  
Synergistic Effects ◽  
Neoadjuvant Treatment ◽  
Software Tool ◽  
New Combination ◽  
Combination Regimen ◽  
Colorectal Cancer Cells

Colorectal cancer (CRC) is among the most commonly occurring cancers. The management of CRC includes laparoscopic surgery, radiotherapy, chemotherapies and neoadjuvant treatment. However, conventional chemotherapies have poor impact on combating CRC and are associated with severe toxic effects and high rates of relapse. Therefore, searching for a new combination regimen is a favorable consideration. The aim of this study was to elucidate the synergistic effect of 5-fluorouracil (5-FU) and diosmetin in an in vitro model on colorectal cancer cells. An MTT assay was conducted on HCT-116 cancer cells and they were treated with a concentration gradient of 5-FU and diosmetin individually and in combination. The combination index (CI) and dose reduction index (DRI) were calculated using CompuSyn software. Isobologram analysis and synergism determination were performed using the Combenefit software tool and the synergy score was calculated using the SynergyFinder 2.0 software tool. The apoptotic features of the cells were determined via an AO/PI double staining assay and an annexin V assay using a fluorescent microscope and the flow cytometry technique, respectively. The findings showed that the DRI of 5-FU was three-fold lower in the combination with a CI value of less than one, which indicates that there was a synergistic effect. The AO/PI microscopic results revealed signs of apoptosis and dead cells after 72 h of treatment. Flow cytometry analysis confirmed that the apoptotic effect of the combination was more prominent compared to 5-FU alone. The findings of this study offer a potential strategy for reducing the cytotoxicity and enhancing the efficacy of 5-FU on colorectal cancer cells through a synergistic study model.

#99: Streptococcus pyogenes Utilizes the Peptide-Based Rgg 2/3 Quorum Sensing System During Oropharyngeal Colonization

2021 ◽  
Vol 10 (Supplement_1) ◽  
pp. S10-S10
Author(s):  
Artemis Gogos ◽  
Michael J Federle
Keyword(s):  
Quorum Sensing ◽  
Streptococcus Pyogenes ◽  
Lymphoid Tissue ◽  
Transcriptional Activator ◽  
Rt Pcr ◽  
Sensing System ◽  
Bacterial Rna ◽  
Quorum Sensing System ◽  
Luciferase Reporters

Abstract Background Streptococcus pyogenes is a human-restricted pathogen most often found in the human nasopharynx. Multiple bacterial factors have been found to contribute to persistent colonization of this niche, and many of these factors are important in mucosal immunity and vaccine development. In this work, we infected mice intranasally with transcriptional regulator mutants of the Rgg2/3 quorum sensing (QS) system—a peptide-based signaling system conserved in all sequenced isolates of S. pyogenes. Methods Three-week-old CD1 mice were intranasally infected with ~107 CFU of S. pyogenes strain MGAS315. Calcium alginate throat swabs were used to monitor nasopharyngeal colonization by the bacteria over time. Luciferase reporters used alongside an IVIS camera were able to show quorum sensing activity levels after inoculation into the mouse nose. Bacterial RNA was isolated from the throat of the mice and quantitative RT–PCR was performed on the samples to corroborate the luciferase reporter data. The nasal-associated lymphoid tissue (NALT) was excised and its supernatants were subjected to 32-plex murine cytokine and chemokine analysis (Millipore). Results Deletion of the QS system’s transcriptional activator (Δrgg2) dramatically diminished the percentage of colonized mice. Deletion of the transcriptional repressor (Δrgg3) increased the percentage of colonized mice compared with wild type. Stimulation of the QS system using synthetic pheromones prior to inoculation did not significantly increase the percentage of animals colonized, indicating that activity of the QS system is responsive to conditions of the host nasopharynx. Mice inoculated with QS-dependent luciferase reporters were subjected to in vivo imaging and showed activation within 1 hour. Bacterial RNA extracted directly from oropharyngeal swabs and evaluated by quantitative RT–PCR subsequently confirmed QS upregulation within 1 hour of inoculation. In the nasal-associated lymphoid tissue (NALT), a muted inflammatory response to the Δrgg2 bacteria suggests that their rapid elimination fails to elicit the previously characterized response to intranasal inoculation of GAS. Conclusions Deletion of the Rgg2 transcriptional activator of the Rgg 2/3 quorum sensing system eliminates colonization of the murine nasopharynx and changes the transcriptional profile of the bacteria in this niche. An existing small-molecule inhibitor of the Rgg2/3 system was unable to inhibit QS activation in vivo, likely due to the suboptimal achievable doses; however, results of our study indicate inhibition of QS may diminish the oropharyngeal colonization of S. pyogenes and argue for further development.

scholarly journals Assessment of Impact of Capital Acquisitions on the Economic Situation of Consolidated Entities in the Czech Republic

2019 ◽  
Vol 67 (5) ◽  
pp. 1335-1345
Author(s):  
Jaroslava Rajchlová ◽  
Anna Fedorová ◽  
Kristina Somerlíková ◽  
Libor Grega
Keyword(s):  
Czech Republic ◽  
Synergistic Effects ◽  
Business Environment ◽  
Fundamental Aspect ◽  
Consolidated Financial Statements ◽  
The Czech Republic ◽  
Individual Assessment ◽  
Research Level ◽  
The Individual ◽  
Parent Companies

Business acquisition constitutes a fundamental aspect of business environment formation. Our research has focused on assessment of impact of capital acquisition on the economic condition of the company. Therefore, the second research level has been initiated, focusing on the individual assessment of the single companies to identify allocation of synergy between consolidated units and parent companies in the Czech Republic. For our research, taking into consideration availability of data and subsequent explanatory value of the results, we will consider synergistic effect as presented in the Ansoff’s concept. Consolidated financial statements of totally 719 groups of accounting entities – business concerns in the Czech Republic has been studied in the research. A composite indicator, as the modern tool for comparison and evaluation of development of entities, has been selected to compare individual economic indicators of parent companies and group of their companies. We believe that developed arguments allow us to formulate conclusion that capital acquisitions, resulting in the years 2008–2013 in the obligation to compile consolidated financial statement, have brought positive financial synergistic effects in majority of cases, and we can rank them among successful business activities.

scholarly journals Bypassing Energy Barriers in Fiber-Polymer Torrefaction

2021 ◽  
Vol 9 ◽  
Author(s):  
Zhuo Xu ◽  
Shreyas S. Kolapkar ◽  
Stas Zinchik ◽  
Ezra Bar-Ziv ◽  
Lucky Ewurum ◽  
...  
Keyword(s):  
Mass Loss ◽  
Synergistic Effects ◽  
Mass Loss Rate ◽  
Reactive Extrusion ◽  
Extrusion Process ◽  
Energy Barriers ◽  
Natural Energy ◽  
Plastic Wastes ◽  
The Individual ◽  
Blend Ratios

The amount of waste generation has been increasing with a significant amount being landfilled. These non-recyclable wastes contain large number of fiber and plastic wastes which can be treated with thermal processes to turn them into energy sources since they have high calorific values, are abundant and usually tipping fees are paid to handle them. This paper studied the torrefaction of non-recyclable paper (fiber) wastes, mixed plastic wastes (MPW) and their blends at different ratios in the temperature range of 250–400°C through thermogravimetric analysis (TGA). The solid residues after the experiments were analyzed by nuclear magnetic resonance (NMR) spectroscopy. Significant synergy between fiber and MPW were observed at the range 250–300°C, showing both increase in the reaction rate as well as the overall mass loss. At 250°C, the maximum mass loss rate was more than two times higher and the mass loss at the end of the experiments were also much higher compared to the expected results. In addition, synergy was weakened with an increase of temperature, disappearing at 400°C. The existence of such interactions between fiber and plastic wastes indicates that the natural energy barriers during the individual torrefaction in paper waste or plastic waste could be bypassed, and the torrefaction of fiber and plastic blend can be achieved at lower temperatures and/or shorter residence times. The MPW and fiber wastes were also compounded by extrusion (to produce pellets) at 220°C with different blend ratios. The fiber-MPW pellets from extrusion were characterized by IR spectroscopy, rheology, thermal analysis and flexural properties and showed significant chemical changes from the non-extruded blends at the same ratios. From IR characterization, it was found that there was significant increase in hydroxyl (OH) group on account of the carbonyl (C = O) and etheric (C-O-C) groups. The interaction between paper and MPW can be attributed to the plastic polymers acting as a hydrogen donor during the reactive extrusion process. Synergistic effects were also found from mechanical and rheological properties.

Modifiable risk factors for coronary heart disease in women

1994 ◽  
Vol 3 (3) ◽  
pp. 177-184 ◽  
Author(s):  
MJ Hanson
Keyword(s):  
Risk Factors ◽  
Coronary Heart Disease ◽  
Heart Disease ◽  
Disease Risk ◽  
Synergistic Effects ◽  
Modifiable Risk Factors ◽  
Additional Risk ◽  
Heart Disease Risk Factors ◽  
The Individual ◽  
Heart Disease Risk

Research in human coronary heart disease has been conducted primarily on males; however, investigators have begun to focus research efforts on female subjects as well. A literature review that identified studies on women and coronary heart disease was done to describe modifiable risk factors for coronary heart disease in women. Several modifiable risk factors such as smoking, hypertension, and disorders of lipid metabolism previously identified for men are also risk factors for women. However, the mechanisms by which some of these risk factors work in women are different from those in men. Moreover, women have additional risk factors related to menopause and, in some cases, the use of oral contraceptives. Significant initial information has been gained concerning women and coronary heart disease risk factors. However, gaps persist in information regarding the individual and synergistic effects of risk factors for CHD in women.

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