scholarly journals Effect of Titanium Dioxide Nanoparticles on the Expression of Efflux Pump and Quorum-Sensing Genes in MDR Pseudomonas aeruginosa Isolates

Antibiotics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 625
Author(s):  
Fatma Y. Ahmed ◽  
Usama Farghaly Aly ◽  
Rehab Mahmoud Abd El-Baky ◽  
Nancy G. F. M. Waly
Keyword(s):  
Titanium Dioxide ◽  
Quorum Sensing ◽  
Biofilm Formation ◽  
Antimicrobial Agents ◽  
Efflux Pump ◽  
Titanium Dioxide Nanoparticles ◽  
Sol Gel ◽  
Efflux Pumps ◽  
Antibiofilm Activity ◽  
The Impact

Most of the infections caused by multi-drug resistant (MDR) P. aeruginosa strains are extremely difficult to be treated with conventional antibiotics. Biofilm formation and efflux pumps are recognized as the major antibiotic resistance mechanisms in MDR P. aeruginosa. Biofilm formation by P. aeruginosa depends mainly on the cell-to-cell communication quorum-sensing (QS) systems. Titanium dioxide nanoparticles (TDN) have been used as antimicrobial agents against several microorganisms but have not been reported as an anti-QS agent. This study aims to evaluate the impact of titanium dioxide nanoparticles (TDN) on QS and efflux pump genes expression in MDR P. aeruginosa isolates. The antimicrobial susceptibility of 25 P. aeruginosa isolates were performed by Kirby–Bauer disc diffusion. Titanium dioxide nanoparticles (TDN) were prepared by the sol gel method and characterized by different techniques (DLS, HR-TEM, XRD, and FTIR). The expression of efflux pumps in the MDR isolates was detected by the determination of MICs of different antibiotics in the presence and absence of carbonyl cyanide m-chlorophenylhydrazone (CCCP). Biofilm formation and the antibiofilm activity of TDN were determined using the tissue culture plate method. The effects of TDN on the expression of QS genes and efflux pump genes were tested using real-time polymerase chain reaction (RT-PCR). The average size of the TDNs was 64.77 nm. It was found that TDN showed a significant reduction in biofilm formation (96%) and represented superior antibacterial activity against P. aeruginosa strains in comparison to titanium dioxide powder. In addition, the use of TDN alone or in combination with antibiotics resulted in significant downregulation of the efflux pump genes (MexY, MexB, MexA) and QS-regulated genes (lasR, lasI, rhll, rhlR, pqsA, pqsR) in comparison to the untreated isolate. TDN can increase the therapeutic efficacy of traditional antibiotics by affecting efflux pump expression and quorum-sensing genes controlling biofilm production.

scholarly journals Peptide Mix from Olivancillaria hiatula Interferes with Cell-to-Cell Communication in Pseudomonas aeruginosa

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Edward Ntim Gasu ◽  
Hubert Senanu Ahor ◽  
Lawrence Sheringham Borquaye
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Biofilm Formation ◽  
Antimicrobial Agents ◽  
Cell Communication ◽  
Microtiter Plate ◽  
Antibiofilm Activity ◽  
Dependent Manner ◽  
Biofilm Inhibition ◽  
Swarming Motility

Bacteria in biofilms are encased in an extracellular polymeric matrix that limits exposure of microbial cells to lethal doses of antimicrobial agents, leading to resistance. In Pseudomonas aeruginosa, biofilm formation is regulated by cell-to-cell communication, called quorum sensing. Quorum sensing facilitates a variety of bacterial physiological functions such as swarming motility and protease, pyoverdine, and pyocyanin productions. Peptide mix from the marine mollusc, Olivancillaria hiatula, has been studied for its antibiofilm activity against Pseudomonas aeruginosa. Microscopy and microtiter plate-based assays were used to evaluate biofilm inhibitory activities. Effect of the peptide mix on quorum sensing-mediated processes was also evaluated. Peptide mix proved to be a good antibiofilm agent, requiring less than 39 μg/mL to inhibit 50% biofilm formation. Micrographs obtained confirmed biofilm inhibition at 1/2 MIC whereas 2.5 mg/mL was required to degrade preformed biofilm. There was a marked attenuation in quorum sensing-mediated phenotypes as well. At 1/2 MIC of peptide, the expression of pyocyanin, pyoverdine, and protease was inhibited by 60%, 72%, and 54%, respectively. Additionally, swarming motility was repressed by peptide in a dose-dependent manner. These results suggest that the peptide mix from Olivancillaria hiatula probably inhibits biofilm formation by interfering with cell-to-cell communication in Pseudomonas aeruginosa.

Confocal and SEM imaging to demonstrate food pathogen- biofilm biocontrol by pyocyanin from Pseudomonas aeruginosa BTRY1

2016 ◽  
Vol 6 (01) ◽  
pp. 5218
Author(s):  
Laxmi Mohandas ◽  
Anju T. R. ◽  
Sarita G. Bhat*
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Antibiofilm Activity ◽  
Opportunistic Pathogens ◽  
Redox Active ◽  
Sem Imaging ◽  
The Impact

An assortment of redox-active phenazine compounds like pyocyanin with their characteristic blue-green colour are synthesized by Pseudomonas aeruginosa, Gram-negative opportunistic pathogens, which are also considered one of the most commercially valuable microorganisms. In this study, pyocyanin from Pseudomonas aeruginosa BTRY1 from food sample was assessed for its antibiofilm activity by micro titer plate assay against strong biofilm producers belonging to the genera Bacillus, Staphylococcus, Brevibacterium and Micrococcus. Pyocyanin inhibited biofilm activity in very minute concentrations. This was also confirmed by Scanning Electron Microscopy (SEM) and Confocal Laser Scanning Microscopy (CLSM). Both SEM and CLSM helped to visualize the biocontrol of biofilm formation by eight pathogens. The imaging and quantification by CLSM also established the impact of pyocyanin on biofilm-biocontrol mainly in the food industry.

Composition and Properties of TiO2 Sol to Produce a Photocatalytic Composite Material

2020 ◽  
Vol 854 ◽  
pp. 45-50
Author(s):  
Ekaterina N. Gubareva ◽  
Valeria V. Strokova ◽  
Yulia N. Ogurtsova ◽  
Pavel S. Baskakov ◽  
Lok Pratap Singh
Keyword(s):  
Composite Material ◽  
Titanium Dioxide ◽  
Ethyl Alcohol ◽  
Titanium Dioxide Nanoparticles ◽  
Sol Gel ◽  
Component Composition ◽  
Optimal Composition ◽  
Optimal Ratio ◽  
Nanosized Titanium Dioxide ◽  
Sol Gel Synthesis

The paper presents the process of sol-gel synthesis of titanium dioxide nanoparticles, the peculiarities of the influence of component composition (titanium precursor content, solvent and stabilizer − surfactant) on the properties of sol and powder obtained on its basis. As a result of the study, the nature of the influence of the type and content of the surfactant in the solution of tetrabutoxytitanium in ethanol on the size of the synthesized particles of titanium dioxide was revealed. The optimal composition of the reaction mixture of TiO–R sol was obtained and the optimal ratio of tetrabutoxytitanium and ethyl alcohol was revealed using which a material with a high content of nanosized titanium dioxide was obtained.

scholarly journals Antimicrobial and Antibiofilm Peptides

Biomolecules ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 652 ◽  
Author(s):  
Angela Di Somma ◽  
Antonio Moretta ◽  
Carolina Canè ◽  
Arianna Cirillo ◽  
Angela Duilio
Keyword(s):  
Antimicrobial Peptides ◽  
Biofilm Formation ◽  
Bacterial Resistance ◽  
Antimicrobial Agents ◽  
Multidrug Resistant ◽  
Resistant Bacteria ◽  
Antibiofilm Activity ◽  
Chronic Infections ◽  
Planktonic Bacteria ◽  
Hostile Environments

The increasing onset of multidrug-resistant bacteria has propelled microbiology research towards antimicrobial peptides as new possible antibiotics from natural sources. Antimicrobial peptides are short peptides endowed with a broad range of activity against both Gram-positive and Gram-negative bacteria and are less prone to trigger resistance. Besides their activity against planktonic bacteria, many antimicrobial peptides also show antibiofilm activity. Biofilms are ubiquitous in nature, having the ability to adhere to virtually any surface, either biotic or abiotic, including medical devices, causing chronic infections that are difficult to eradicate. The biofilm matrix protects bacteria from hostile environments, thus contributing to the bacterial resistance to antimicrobial agents. Biofilms are very difficult to treat, with options restricted to the use of large doses of antibiotics or the removal of the infected device. Antimicrobial peptides could represent good candidates to develop new antibiofilm drugs as they can act at different stages of biofilm formation, on disparate molecular targets and with various mechanisms of action. These include inhibition of biofilm formation and adhesion, downregulation of quorum sensing factors, and disruption of the pre-formed biofilm. This review focuses on the proprieties of antimicrobial and antibiofilm peptides, with a particular emphasis on their mechanism of action, reporting several examples of peptides that over time have been shown to have activity against biofilm.

scholarly journals Control of Biofilm Formation in Healthcare: Recent Advances Exploiting Quorum-Sensing Interference Strategies and Multidrug Efflux Pump Inhibitors

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1676 ◽  
Author(s):  
Bindu Subhadra ◽  
Dong Kim ◽  
Kyungho Woo ◽  
Surya Surendran ◽  
Chul Choi
Keyword(s):  
Quorum Sensing ◽  
Biofilm Formation ◽  
Efflux Pump ◽  
Financial Burden ◽  
Multidrug Efflux ◽  
Multidrug Efflux Pump ◽  
Persistent Infections ◽  
Healthcare Settings ◽  
Recent Advances ◽  
Multidrug Efflux Pumps

Biofilm formation in healthcare is an issue of considerable concern, as it results in increased morbidity and mortality, imposing a significant financial burden on the healthcare system. Biofilms are highly resistant to conventional antimicrobial therapies and lead to persistent infections. Hence, there is a high demand for novel strategies other than conventional antibiotic therapies to control biofilm-based infections. There are two approaches which have been employed so far to control biofilm formation in healthcare settings: one is the development of biofilm inhibitors based on the understanding of the molecular mechanism of biofilm formation, and the other is to modify the biomaterials which are used in medical devices to prevent biofilm formation. This review will focus on the recent advances in anti-biofilm approaches by interrupting the quorum-sensing cellular communication system and the multidrug efflux pumps which play an important role in biofilm formation. Research efforts directed towards these promising strategies could eventually lead to the development of better anti-biofilm therapies than the conventional treatments.

scholarly journals Impact of Titanium Dioxide Nanoparticles on Cd Phytotoxicity and Bioaccumulation in Rice (Oryza sativa L.)

2020 ◽  
Vol 17 (9) ◽  
pp. 2979 ◽  
Author(s):  
Wei Zhang ◽  
Jinghua Long ◽  
Jianmin Geng ◽  
Jie Li ◽  
Zhongyi Wei
Keyword(s):  
Titanium Dioxide ◽  
Oryza Sativa ◽  
Plant Height ◽  
Oryza Sativa L ◽  
Titanium Dioxide Nanoparticles ◽  
Engineered Nanoparticles ◽  
Control Treatment ◽  
Booting Stage ◽  
Tio2 Nps ◽  
The Impact

The impact of engineered nanoparticles (ENPs) on the migration and toxicity of coexisting pollutants is still unclear, especially in soil media. This study aims to evaluate the impact of titanium dioxide nanoparticles (TiO2 NPs) on the phytotoxicity of cadmium (Cd) to Oryza sativa L., and the migration of cadmium (Cd) in the soil-rice system. Three different Cd stress groups (C1 group: 1.0 mg kg−1, C2 group: 2.5 mg kg−1 and C3 group: 5.0 mg kg−1) were set in the pot experiment, and the target concentration of TiO2 NPs in each group were 0 mg kg−1 (T0), 50 mg kg−1 (T1), 100 mg kg−1 (T2) and 500 mg kg−1 (T3). Plant height and biomass decreased with the increasing of Cd content in paddy soil. TiO2 NPs could lower the phytotoxicity of Cd in terms of the changes in the morphological and biochemical characteristics, especially in the tillering and booting stage. In the tillering stage, TiO2 NPs addition caused a significant increase in plant height, biomass and the total chlorophyll content in the leaves of Oryza saliva L. In the booting stage, TiO2 NPs addition caused a 15% to 32% and 24% to 48% reduction of malondialdehyde (MDA) content for the C2 and C3 group, respectively, compared to that of the respective control treatment (T0). TiO2-NPs addition reduced the activity of peroxidase (POD) in the leaves in the booting and heading stage, and the activity of catalase (CAT) in the tillering stage. In the C1 and C2 group, the grain Cd content in the 100 and 500 mg kg−1 TiO2 NPs treatments reached 0.47–0.84 mg kg−1, obviously higher than that of the treatment without TiO2 NPs (0.27–0.32 mg kg−1), suggesting that TiO2-NPs could promote Cd migration in the soil-rice system.

scholarly journals The impact of quorum sensing and swarming motility on Pseudomonas aeruginosa biofilm formation is nutritionally conditional

2006 ◽  
Vol 62 (5) ◽  
pp. 1264-1277 ◽  
Author(s):  
Joshua D. Shrout ◽  
David L. Chopp ◽  
Collin L. Just ◽  
Morten Hentzer ◽  
Michael Givskov ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Biofilm Formation ◽  
Swarming Motility ◽  
The Impact

Photoconversion of CO2 using copper-modified titanium dioxide nanoparticles

2011 ◽  
Vol 76 (11) ◽  
pp. 1335-1346 ◽  
Author(s):  
Jing Wei ◽  
Xin Tan ◽  
Tao Yu ◽  
Lin Zhao
Keyword(s):  
Titanium Dioxide ◽  
Photoelectron Spectroscopy ◽  
Titanium Dioxide Nanoparticles ◽  
Sol Gel ◽  
Chemical Properties ◽  
High Photocatalytic Activity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Uv Illumination ◽  
One Step

A series of copper-modified titanium dioxide (Cu/TiO2) nanoparticles were synthesized via one-step sol-gel method. The crystal structure and chemical properties were characterized using X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The Cu/TiO2nanoparticles were applied to CO2photoconversion and the yield of formaldehyde was used to evaluate the photocatalytic performance. The optimum amount of copper modifying was 0.6 wt.% and the yield of formaldehyde was 946 μmol/gcatunder UV illumination for 6 h. 20 wt.% Cu/TiO2also performed a high photocatalytic activity, which yielded 433 μmol/gcatformaldehyde under UV illumination for 6 h.

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