Poly(l-ornithine)-Grafted Zinc Phthalocyanines as Dual-Functional Antimicrobial Agents with Intrinsic Membrane Damage and Photothermal Ablation Capacity

2021 ◽  
Author(s):  
Maochao Zheng ◽  
Huanchang Lin ◽  
Wancong Zhang ◽  
Shijie Tang ◽  
Daojun Liu ◽  
...  
Keyword(s):  
Antimicrobial Agents ◽  
Membrane Damage ◽  
Dual Functional ◽  
Photothermal Ablation ◽  
Zinc Phthalocyanines

scholarly journals EcDBS1R6: A new broad-spectrum cationic antibacterial peptide derived from a signal peptide sequence

2019 ◽  
Author(s):  
William F. Porto ◽  
Luz N. Irazazabal ◽  
Vincent Humblot ◽  
Evan F. Haney ◽  
Suzana M. Ribeiro ◽  
...  
Keyword(s):  
Signal Peptide ◽  
Broad Spectrum ◽  
Antimicrobial Agents ◽  
Membrane Damage ◽  
Membrane Integrity ◽  
Peptide Sequence ◽  
World Health ◽  
Signal Peptides ◽  
Microscopy Imaging ◽  
Signal Peptide Sequence

ABSTRACTBacterial infections represent a major worldwide health problem, with an special highlight on Gram-negative bacteria, which were assigned by the World Health Organization (WHO) as the most critical priority for development of novel antimicrobial compounds. Antimicrobial peptides (AMPs) have been considered as potential alternative agents for treating these infections. Here we demonstrated the broad-spectrum activity of EcDBS1R6, a peptide derived from a signal peptide sequence of Escherichia coli that we previously turned into an AMP by making changes predicted through the Joker algorithm. Signal peptides are known to naturally interact with membranes; however, the modifications introduced by Joker made this peptide capable of killing bacteria. Membrane damage of the bacterial cells was observed by measuring membrane integrity using fluorescent probes and through scanning electron microscopy imaging. Structural analysis revealed that the C-terminus was unable to fold into an α-helix, indicating that the EcDBS1R6 antibacterial activity core was located at the N-terminus, corresponding to the signal peptide portion of the parent peptide. Therefore, the strategy of transforming signal peptides into AMPs seems to be promising and could be used for producing novel antimicrobial agents.

scholarly journals Bacterial Killing by Dry Metallic Copper Surfaces

2010 ◽  
Vol 77 (3) ◽  
pp. 794-802 ◽  
Author(s):  
Christophe Espírito Santo ◽  
Ee Wen Lam ◽  
Christian G. Elowsky ◽  
Davide Quaranta ◽  
Dylan W. Domaille ◽  
...  
Keyword(s):  
Antimicrobial Agents ◽  
Scientific Explanation ◽  
Copper Ions ◽  
Metallic Copper ◽  
Membrane Damage ◽  
Dna Lesions ◽  
Cell Integrity ◽  
Copper Uptake ◽  
Bacterial Killing ◽  
Copper Surfaces

ABSTRACTMetallic copper surfaces rapidly and efficiently kill bacteria. Cells exposed to copper surfaces accumulated large amounts of copper ions, and this copper uptake was faster from dry copper than from moist copper. Cells suffered extensive membrane damage within minutes of exposure to dry copper. Further, cells removed from copper showed loss of cell integrity. Acute contact with metallic copper surfaces did not result in increased mutation rates or DNA lesions. These findings are important first steps for revealing the molecular sensitive targets in cells lethally challenged by exposure to copper surfaces and provide a scientific explanation for the use of copper surfaces as antimicrobial agents for supporting public hygiene.

Dual functional ionic liquids as plasticisers and antimicrobial agents for medical polymers

2011 ◽  
Vol 13 (6) ◽  
pp. 1527 ◽  
Author(s):  
Seong Ying Choi ◽  
Héctor Rodríguez ◽  
Arsalan Mirjafari ◽  
Deirdre F. Gilpin ◽  
Stephanie McGrath ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Antimicrobial Agents ◽  
Dual Functional

Dual-functional peptide conjugated gold nanorods for the detection and photothermal ablation of pathogenic bacteria

2018 ◽  
Vol 6 (46) ◽  
pp. 7643-7651 ◽  
Author(s):  
Qingyu Chen ◽  
Liwei Zhang ◽  
Yonghai Feng ◽  
Fan Shi ◽  
Yibing Wang ◽  
...  
Keyword(s):  
Gold Nanorods ◽  
Pathogenic Bacteria ◽  
Specific Binding ◽  
Dual Functional ◽  
Photothermal Ablation ◽  
Functional Peptide

Au@peptide937 nanorods for detecting bacteria by specific binding and killing bacteria due to the local hyperthermal effect.

scholarly journals New Functionalized Macroparticles for Environmentally Sustainable Biofilm Control in Water Systems

Antibiotics ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 399
Author(s):  
Ana C. Barros ◽  
Ana Pereira ◽  
Luis F. Melo ◽  
Juliana P. S. Sousa
Keyword(s):  
Cell Membrane ◽  
Antimicrobial Agents ◽  
Membrane Damage ◽  
Membrane Integrity ◽  
Membrane System ◽  
Bacterial Cells ◽  
Cell Membrane Integrity ◽  
Cell Membrane Damage ◽  
Environmentally Sustainable ◽  
Partial Blocking

Reverse osmosis (RO) depends on biocidal agents to control the operating costs associated to biofouling, although this implies the discharge of undesired chemicals into the aquatic environment. Therefore, a system providing pre-treated water free of biocides arises as an interesting solution to minimize the discharge of chemicals while enhancing RO filtration performance by inactivating bacteria that could form biofilms on the membrane system. This work proposes a pretreatment approach based on the immobilization of an industrially used antimicrobial agent (benzalkonium chloride—BAC) into millimetric aluminum oxide particles with prior surface activation with DA—dopamine. The antimicrobial efficacy of the functionalized particles was assessed against Escherichia coli planktonic cells through culturability and cell membrane integrity analysis. The results showed total inactivation of bacterial cells within five min for the highest particle concentration and 100% of cell membrane damage after 15 min for all concentrations. When reusing the same particles, a higher contact time was needed to reach the total inactivation, possibly due to partial blocking of immobilized biocide by dead bacteria adhering to the particles and to the residual leaching of biocide. The overall results support the use of Al2O3-DA-BAC particles as antimicrobial agents for sustainable biocidal applications in continuous water treatment systems.

scholarly journals Antibacterial activities, proposed mode of action and cytotoxicity of leaf extracts from Triumfetta welwitschii against Pseudomonas aeruginosa

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Molly Mombeshora ◽  
Stanley Mukanganyama
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antibacterial Activity ◽  
Nosocomial Infections ◽  
Mode Of Action ◽  
Antimicrobial Agents ◽  
Membrane Damage ◽  
Membrane Integrity ◽  
Antibacterial Activities ◽  
Leaf Extracts ◽  
Broth Microdilution Method

Abstract Background Pseudomonas aeruginosa has become a main cause of Gram-negative infection, particularly in patients with compromised immunity. High rates of resistance to antibiotics are associated with nosocomial infections caused by P. aeruginosa strains. The search for novel antimicrobials has been necessitated by the emergence of antimicrobial resistance in some bacteria Plant-based antimicrobials has great potential to combat microbial infections using a variety of mechanisms. Triumfetta welwitschii plant roots are traditionally used to treat symptoms of diarrhoea and fever, suggesting that it possess antimicrobial and immunomodulatory effects. Since research investigating antimicrobial properties of the roots of Triumfetta welwitschii has been explored, there is need to investigate the antimicrobial activity of its leaf extracts in order to probe their prospective use as new antimicrobial agents that can be used to combat nosocomial infections. The objective of this study was to evaluate the antibacterial activities, the mode of action and cytotoxicity of T. welwitschii leaf extracts. Method Extracts of T. welwitschii leaves were obtained using eight different solvents, the serial exhaustive extraction method and the cold maceration technique. In vitro antibacterial activity evaluation of the extracts was done on eight bacterial isolates using the broth microdilution method. The mode of action for the most potent extracts was investigated using the rhodamine 6G efflux assay and the propidium iodide-based membrane damage assay. Toxicity of the extracts was evaluated using the haemolytic and MTT (3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) assays. Results The results showed that acetone, ethanol and dichlorometane: methanol extracts had the most potent antibacterial activities against Pseudomonas aeruginosa (ATCC 27853). All three extracts caused membrane disruption of P. aeruginosa as shown by nucleic acid leakage. All three extracts were unable to inhibit efflux pumps. Conclusion The presence of antibacterial activities and low toxicity shown by the extracts indicates that the plant may be a source of effective antibacterial against some bacterial infections caused by P. aeruginosa. The disruption of membrane integrity is one possible mode of action of antibacterial activity of the potent extracts.

Synthesis of dual functional pyrimidinium ionic liquids as reaction media and antimicrobial agents

RSC Advances ◽  
2016 ◽  
Vol 6 (108) ◽  
pp. 106806-106820 ◽  
Author(s):  
Kamna Goel ◽  
Smritilekha Bera ◽  
Man Singh ◽  
Dhananjoy Mondal
Keyword(s):  
Ionic Liquids ◽  
Antibacterial Agents ◽  
Antimicrobial Agents ◽  
Dual Functional ◽  
Reaction Media

This article describes a two-step synthesis of twenty N-alkyl pyrimidinium ionic liquids through N-alkylation of pyrimidine with n-alkyl (C1–C10) halides followed by anion metathesis and their dual applications as reaction media and antibacterial agents.

Antibacterial Effects of Phytic Acid against Foodborne Pathogens and Investigation of Its Mode of Action

2019 ◽  
Vol 82 (5) ◽  
pp. 826-833 ◽  
Author(s):  
QI ZHOU ◽  
YU ZHAO ◽  
HUI DANG ◽  
YUANYUE TANG ◽  
BAOSHAN ZHANG
Keyword(s):  
Cell Membrane ◽  
Phytic Acid ◽  
Foodborne Pathogens ◽  
Cell Morphology ◽  
Antimicrobial Agents ◽  
Membrane Damage ◽  
Membrane Integrity ◽  
Bacterial Cells ◽  
Antibacterial Effects ◽  
Intracellular Atp

ABSTRACTThis study investigated the antimicrobial mechanism of phytic acid (PA) and its antibacterial effects in combination with ethanol. The MIC of PA on Escherichia coli ATCC 11229, Staphylococcus aureus ATCC 6538P, Bacillus subtilis ATCC 6633, and Salmonella Typhimurium CICC 27483 were 0.24, 0.20, 0.26, and 0.28% (w/w), respectively. E. coli ATCC 11229 and S. aureus ATCC 6538P were selected to investigate the mechanism of PA by analyzing its effects at 1/2MIC and at MIC on the cell morphology, intracellular ATP, and cell membrane integrity. Environmental scanning electron microscope images revealed that PA was able to change the cell morphology and disrupt the intercellular adhesion. PA retarded bacterial growth and caused cell membrane dysfunction, which was accompanied by decreased intracellular ATP concentrations. Flow cytometry analysis further revealed that almost all the bacterial cells were damaged after treatment with PA at its MIC for 2 h. Moreover, PA has a synergistic antimicrobial ability when used in combination with ethanol. These results suggested that PA is effective in inhibiting growth of foodborne pathogens mainly by the mechanism of cell membrane damage and to provide a theoretical basis for the development of natural antimicrobial agents in the food industry.

Facile synthesis of polypyrrole–rhodamine B nanoparticles for self-monitored photothermal therapy of cancer cells

2020 ◽  
Vol 8 (5) ◽  
pp. 1033-1039 ◽  
Author(s):  
Xiao-Hui Wang ◽  
Xue-Qiao Chen ◽  
Hong-Shang Peng ◽  
Xiao-Fei Wei ◽  
Xiao-Juan Wang ◽  
...  
Keyword(s):  
Cancer Cells ◽  
Real Time ◽  
Rhodamine B ◽  
Photothermal Therapy ◽  
Temperature Monitoring ◽  
Facile Synthesis ◽  
Functional Nanoparticles ◽  
Dual Functional ◽  
Photothermal Ablation

Biocompatible dual-functional nanoparticles combining polypyrrole with rhodamine B are constructed for photothermal ablation of cancer cells and real-time temperature monitoring during PTT.

scholarly journals Isopropoxy Benzene Guanidine Kills Staphylococcus aureus Without Detectable Resistance

2021 ◽  
Vol 12 ◽  
Author(s):  
Xiufeng Zhang ◽  
Wenguang Xiong ◽  
Xianfeng Peng ◽  
Yixing Lu ◽  
Jie Hao ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Agents ◽  
Drug Repositioning ◽  
Membrane Damage ◽  
Membrane Integrity ◽  
Multidrug Resistant ◽  
Lower Probability ◽  
Conventional Antibiotics ◽  
Effective Drugs

Serious infections caused by multidrug-resistant Staphylococcus aureus clearly urge the development of new antimicrobial agents. Drug repositioning has emerged as an alternative approach that enables us to rapidly identify effective drugs. We first reported a guanidine compound, isopropoxy benzene guanidine, had potent antibacterial activity against S. aureus. Unlike conventional antibiotics, repeated use of isopropoxy benzene guanidine had a lower probability of resistance section. We found that isopropoxy benzene guanidine triggered membrane damage by disrupting the cell membrane potential and cytoplasmic membrane integrity. Furthermore, we demonstrated that isopropoxy benzene guanidine is capable of treating invasive MRSA infections in vivo studies. These findings provided strong evidence that isopropoxy benzene guanidine represents a new chemical lead for novel antibacterial agent against multidrug-resistant S. aureus infections.

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