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Odžak R, Crnčević D, Sabljić A, Krce L, Paladin A, Primožič I, Šprung M. Further Study of the Polar Group's Influence on the Antibacterial Activity of the 3-Substituted Quinuclidine Salts with Long Alkyl Chains. Antibiotics (Basel) 2023; 12:1231. [PMID: 37627651 PMCID: PMC10451673 DOI: 10.3390/antibiotics12081231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 07/20/2023] [Accepted: 07/24/2023] [Indexed: 08/27/2023] Open
Abstract
Quaternary ammonium compounds (QACs) are among the most potent antimicrobial agents increasingly used by humans as disinfectants, antiseptics, surfactants, and biological dyes. As reports of bacterial co- and cross-resistance to QACs and their toxicity have emerged in recent years, new attempts are being made to develop soft QACs by introducing hydrolyzable groups that allow their controlled degradation. However, the development of such compounds has been hindered by the structural features that affect the bioactivity of QACs, one of them being polarity of the substituent near the quaternary center. To further investigate the influence of the polar group on the bioactivity of QACs, we synthesized 3-aminoquinuclidine salts for comparison with their structural analogues, 3-acetamidoquinuclidines. We found that the less polar amino-substituted compounds exhibited improved antibacterial activity over their more polar amide analogues. In addition to their better minimum inhibitory concentrations, the candidates were excellent at suppressing Staphylococcus aureus biofilm formation and killing bacteria almost immediately, as shown by the flow cytometry measurements. In addition, two candidates, namely QNH2-C14 and QNH2-C16, effectively suppressed bacterial growth even at concentrations below the MIC. QNH2-C14 was particularly effective at subinhibitory concentrations, inhibiting bacterial growth for up to 6 h. In addition, we found that the compounds targeted the bacterial membrane, leading to its perforation and subsequent cell death. Their low toxicity to human cells and low potential to develop bacterial resistance suggest that these compounds could serve as a basis for the development of new QACs.
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Affiliation(s)
- Renata Odžak
- Department of Chemistry, Faculty of Science, University of Split, R. Bošković 33, 21000 Split, Croatia; (R.O.); (D.C.); (A.S.)
| | - Doris Crnčević
- Department of Chemistry, Faculty of Science, University of Split, R. Bošković 33, 21000 Split, Croatia; (R.O.); (D.C.); (A.S.)
- Doctoral Study of Biophysics, Faculty of Science, University of Split, R. Bošković 33, 21000 Split, Croatia
| | - Antonio Sabljić
- Department of Chemistry, Faculty of Science, University of Split, R. Bošković 33, 21000 Split, Croatia; (R.O.); (D.C.); (A.S.)
- Doctoral Study of Biophysics, Faculty of Science, University of Split, R. Bošković 33, 21000 Split, Croatia
| | - Lucija Krce
- Department of Physics, Faculty of Science, University of Split, R. Bošković 33, 21000 Split, Croatia;
| | - Antonela Paladin
- Department of Biology, Faculty of Science, University of Split, R. Bošković 33, 21000 Split, Croatia;
| | - Ines Primožič
- Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000 Zagreb, Croatia;
| | - Matilda Šprung
- Department of Chemistry, Faculty of Science, University of Split, R. Bošković 33, 21000 Split, Croatia; (R.O.); (D.C.); (A.S.)
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Ilić K, Kalčec N, Krce L, Aviani I, Turčić P, Pavičić I, Vinković Vrček I. Toxicity of nanomixtures to human macrophages: Joint action of silver and polystyrene nanoparticles. Chem Biol Interact 2022; 368:110225. [DOI: 10.1016/j.cbi.2022.110225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 10/10/2022] [Accepted: 10/18/2022] [Indexed: 11/29/2022]
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Ilić K, Krce L, Rodriguez-Ramos J, Rico F, Kalčec N, Aviani I, Turčić P, Pavičić I, Vinković Vrček I. Cytotoxicity of nanomixture: Combined action of silver and plastic nanoparticles on immortalized human lymphocytes. J Trace Elem Med Biol 2022; 73:127004. [PMID: 35617720 DOI: 10.1016/j.jtemb.2022.127004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 04/09/2022] [Accepted: 05/17/2022] [Indexed: 11/25/2022]
Abstract
BACKGROUND Silver nanoparticles (AgNP) are one of the most commercialized types of nanomaterials, with a wide range of applications owing to their antimicrobial activity. They are particularly important in hospitals and other healthcare settings, where they are used to maintain sterility of surfaces, textiles, catheters, medical implants, and more. However, AgNP can not only harm bacteria, but also damage mammalian cells and tissue. While the potential toxicity of AgNP is an understood risk, there is a lack of data on their toxicity in combination with polymeric materials, especially plastic nanoparticles such as polystyrene nanoparticles (PSNP) that can be released from surfaces of polystyrene devices during their medical use. AIM This study aimed to investigate combined effect of AgNP and nanoplastics on human immune response. METHODS Cells were treated with a range of PSNP and AgNP concentrations, either applied alone or in combination. Cytotoxicity, induction of apoptosis, generation of oxidative stress, uptake efficiency, intracellular localization and nanomechanical cell properties were selected as exposure biomarkers. RESULTS Collected experimental data showed that nanomixture induced oxidative stress, apoptosis and mortality of Jurkat cells stronger than its individual components. Cell treatment with AgNP/PSNP mixture also significantly changed cell mechanical properties, evidenced by reduction of cells' Young Modulus. CONCLUSION AgNP and PSNP showed additive toxic effects on immortalized human lymphocytes, evidenced by increase in cellular oxidative stress, induction of apoptosis, and reduction of cell stiffness. These results have important implications for using AgNP and PSNP in medical contexts, particularly for long-term medical implants.
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Affiliation(s)
- Krunoslav Ilić
- Institute for Medical Research and Occupational Health, Zagreb, Croatia
| | - Lucija Krce
- University of Split, Faculty of Science, Department of Physics, Split, Croatia
| | | | - Felix Rico
- Aix-Marseille University, INSERM, CNRS, LAI, 13009 Marseille, France
| | - Nikolina Kalčec
- Institute for Medical Research and Occupational Health, Zagreb, Croatia
| | - Ivica Aviani
- University of Split, Faculty of Science, Department of Physics, Split, Croatia
| | - Petra Turčić
- University of Zagreb, Faculty of Pharmacy and Biochemistry, Zagreb, Croatia
| | - Ivan Pavičić
- Institute for Medical Research and Occupational Health, Zagreb, Croatia
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Rončević T, Gerdol M, Mardirossian M, Maleš M, Cvjetan S, Benincasa M, Maravić A, Gajski G, Krce L, Aviani I, Hrabar J, Trumbić Ž, Derks M, Pallavicini A, Weingarth M, Zoranić L, Tossi A, Mladineo I. Anisaxins, helical antimicrobial peptides from marine parasites, kill resistant bacteria by lipid extraction and membrane disruption. Acta Biomater 2022; 146:131-144. [PMID: 35470073 DOI: 10.1016/j.actbio.2022.04.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 04/12/2022] [Accepted: 04/14/2022] [Indexed: 12/21/2022]
Abstract
An infecting and propagating parasite relies on its innate defense system to evade the host's immune response and to survive challenges from commensal bacteria. More so for the nematode Anisakis, a marine parasite that during its life cycle encounters both vertebrate and invertebrate hosts and their highly diverse microbiotas. Although much is still unknown about how the nematode mitigates the effects of these microbiota, its antimicrobial peptides likely play an important role in its survival. We identified anisaxins, the first cecropin-like helical antimicrobial peptides originating from a marine parasite, by mining available genomic and transcriptomic data for Anisakis spp. These peptides are potent bactericidal agents in vitro, selectively active against Gram-negative bacteria, including multi-drug resistant strains, at sub-micromolar concentrations. Their interaction with bacterial membranes was confirmed by solid state NMR (ssNMR) and is highly dependent on the peptide concentration as well as peptide to lipid ratio, as evidenced by molecular dynamics (MD) simulations. MD results indicated that an initial step in the membranolytic mode of action involves membrane bulging and lipid extraction; a novel mechanism which may underline the peptides' potency. Subsequent steps include membrane permeabilization leading to leakage of molecules and eventually cell death, but without visible macroscopic damage, as shown by atomic force microscopy and flow cytometry. This membranolytic antibacterial activity does not translate to cytotoxicity towards human peripheral blood mononuclear cells (HPBMCs), which was minimal at well above bactericidal concentrations, making anisaxins promising candidates for further drug development. STATEMENT OF SIGNIFICANCE: Witnessing the rapid spread of antibiotic resistance resulting in millions of infected and dozens of thousands dying worldwide every year, we identified anisaxins, antimicrobial peptides (AMPs) from marine parasites, Anisakis spp., with potent bactericidal activity and selectivity towards multi-drug resistant Gram-negative bacteria. Anisaxins are membrane-active peptides, whose activity, very sensitive to local peptide concentrations, involves membrane bulging and lipid extraction, leading to membrane permeabilization and bacterial cell death. At the same time, their toxicity towards host cells is negligible, which is often not the case for membrane-active AMPs, therefore making them suitable drug candidates. Membrane bulging and lipid extraction are novel concepts that broaden our understanding of peptide interactions with bacterial functional structures, essential for future design of such biomaterials.
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Affiliation(s)
- Tomislav Rončević
- Department of Biology, Faculty of Science, University of Split, Ruđera Boškovića 33, Split 21000, Croatia.
| | - Marco Gerdol
- Department of Life Sciences, University of Trieste, Trieste 34127, Italy
| | - Mario Mardirossian
- Department of Medical Sciences, University of Trieste, Trieste 34125, Italy
| | - Matko Maleš
- Faculty of Maritime Studies, University of Split, Split 21000, Croatia
| | - Svjetlana Cvjetan
- Laboratory for Aquaculture, Institute of Oceanography and Fisheries, Split 21000, Croatia
| | - Monica Benincasa
- Department of Life Sciences, University of Trieste, Trieste 34127, Italy
| | - Ana Maravić
- Department of Biology, Faculty of Science, University of Split, Ruđera Boškovića 33, Split 21000, Croatia
| | - Goran Gajski
- Mutagenesis Unit, Institute for Medical Research and Occupational Health, Zagreb 10000, Croatia
| | - Lucija Krce
- Department of Physics, Faculty of Science, University of Split, Split 21000, Croatia
| | - Ivica Aviani
- Department of Physics, Faculty of Science, University of Split, Split 21000, Croatia
| | - Jerko Hrabar
- Laboratory for Aquaculture, Institute of Oceanography and Fisheries, Split 21000, Croatia
| | - Željka Trumbić
- University Department of Marine Studies, University of Split, Split 21000, Croatia
| | - Maik Derks
- NMR spectroscopy, Bijvoet Centre for Biomolecular Research, University of Utrecht, Utrecht 3584CH, The Netherlands; Membrane Biochemistry and Biophysics, Bijvoet Centre for Biomolecular Research, Department of Chemistry, Utrecht University, Padualaan 8, Utrecht 3584 CH, The Netherlands
| | - Alberto Pallavicini
- Department of Life Sciences, University of Trieste, Trieste 34127, Italy; Oceanography Division, Istituto Nazionale di Oceanografia e di Geofisica Sperimentale - OGS, Trieste, Italy
| | - Markus Weingarth
- NMR spectroscopy, Bijvoet Centre for Biomolecular Research, University of Utrecht, Utrecht 3584CH, The Netherlands
| | - Larisa Zoranić
- Department of Physics, Faculty of Science, University of Split, Split 21000, Croatia
| | - Alessandro Tossi
- Department of Life Sciences, University of Trieste, Trieste 34127, Italy
| | - Ivona Mladineo
- Laboratory of Functional Helminthology, Biology Centre Czech Academy of Sciences, Institute of Parasitology BC CAS, Branisovska 31, Ceske Budejovice 37005, Czech Republic.
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Crnčević D, Krce L, Cvitković M, Brkljača Z, Sabljić A, Vuko E, Primožič I, Odžak R, Šprung M. New Membrane Active Antibacterial and Antiviral Amphiphiles Derived from Heterocyclic Backbone of Pyridinium-4-Aldoxime. Pharmaceuticals (Basel) 2022; 15:ph15070775. [PMID: 35890073 PMCID: PMC9315884 DOI: 10.3390/ph15070775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 06/15/2022] [Accepted: 06/20/2022] [Indexed: 02/06/2023] Open
Abstract
Quaternary ammonium salts (QAS) are irreplaceable membrane-active antimicrobial agents that have been widely used for nearly a century. Cetylpyridinium chloride (CPC) is one of the most potent QAS. However, recent data from the literature indicate that CPC activity against resistant bacterial strains is decreasing. The major QAS resistance pathway involves the QacR dimer, which regulates efflux pump expression. A plausible approach to address this issue is to structurally modify the CPC structure by adding other biologically active functional groups. Here, a series of QAS based on pyridine-4-aldoxime were synthesized, characterized, and tested for antimicrobial activity in vitro. Although we obtained several potent antiviral candidates, these candidates had lower antibacterial activity than CPC and were not toxic to human cell lines. We found that the addition of an oxime group to the pyridine backbone resulted in derivatives with large topological polar surfaces and with unfavorable cLog P values. Investigation of the antibacterial mode of action, involving the cell membrane, revealed altered cell morphologies in terms of corrugated and/or disrupted surface, while 87% of the cells studied exhibited a permeabilized membrane after 3 h of treatment at 4 × minimum inhibitory concentration (MIC). Molecular dynamic (MD) simulations of the interaction of QacR with a representative candidate showed rapid dimer disruption, whereas this was not observed for QacR and QacR bound to the structural analog CPC. This might explain the lower bioactivity of our compounds, as they are likely to cause premature expression of efflux pumps and thus activation of resistance.
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Affiliation(s)
- Doris Crnčević
- Department of Chemistry, Faculty of Science, University of Split, R. Bošković 33, 21 000 Split, Croatia; (D.C.); (A.S.)
- Doctoral Study of Biophysics, Faculty of Science, University of Split, R. Bošković 33, 21 000 Split, Croatia
| | - Lucija Krce
- Department of Physics, Faculty of Science, University of Split, R. Bošković 33, 21 000 Split, Croatia; (L.K.); (M.C.)
| | - Mislav Cvitković
- Department of Physics, Faculty of Science, University of Split, R. Bošković 33, 21 000 Split, Croatia; (L.K.); (M.C.)
| | - Zlatko Brkljača
- Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička c. 54, 10 000 Zagreb, Croatia;
- Selvita Ltd., Prilaz Baruna Filipovića 29, 10 000 Zagreb, Croatia
| | - Antonio Sabljić
- Department of Chemistry, Faculty of Science, University of Split, R. Bošković 33, 21 000 Split, Croatia; (D.C.); (A.S.)
- Doctoral Study of Biophysics, Faculty of Science, University of Split, R. Bošković 33, 21 000 Split, Croatia
| | - Elma Vuko
- Department of Biology, Faculty of Science, University of Split, R. Bošković 33, 21 000 Split, Croatia;
| | - Ines Primožič
- Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10 000 Zagreb, Croatia;
| | - Renata Odžak
- Department of Chemistry, Faculty of Science, University of Split, R. Bošković 33, 21 000 Split, Croatia; (D.C.); (A.S.)
- Correspondence: (R.O.); (M.Š.)
| | - Matilda Šprung
- Department of Chemistry, Faculty of Science, University of Split, R. Bošković 33, 21 000 Split, Croatia; (D.C.); (A.S.)
- Correspondence: (R.O.); (M.Š.)
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Pacor S, Benincasa M, Musso MV, Krce L, Aviani I, Pallavicini A, Scocchi M, Gerdol M, Mardirossian M. The proline-rich myticalins from Mytilus galloprovincialis display a membrane-permeabilizing antimicrobial mode of action. Peptides 2021; 143:170594. [PMID: 34118363 DOI: 10.1016/j.peptides.2021.170594] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 05/19/2021] [Accepted: 06/03/2021] [Indexed: 12/15/2022]
Abstract
Bivalve mollusks are continuously exposed to potentially pathogenic microorganisms living in the marine environment. Not surprisingly, these filter-feeders developed a robust innate immunity to protect themselves, which includes a broad panel of antimicrobial peptides. Among these, myticalins represent a recently discovered family of linear cationic peptides expressed in the gills of Mytilus galloprovincialis. Even though myticalins and insect and mammalian proline-rich antimicrobial peptides (PrAMPs) share a similar amino acid composition, we here show that none of the tested mussel peptides use a non-lytic mode of action relying on the bacterial transporter SbmA. On the other hand, all the tested myticalins perturbed and permeabilized the membranes of E. coli BW25113, as shown by flow-cytometry and atomic force microscopy. Circular dichroism spectra revealed that most myticalins did not adopt recognizable secondary structures in the presence of amphipathic environments, such as biological membranes. To explore possible uses of myticalins for biotech, we assessed their biocompatibility with a human cell line. Non-negligible cytotoxic effects displayed by myticalins indicate that their optimization would be required before their further use as lead compounds in the development of new antibiotics.
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Affiliation(s)
- Sabrina Pacor
- Department of Life Sciences, Via Licio Giorgieri 5, University of Trieste, 34127 Trieste, Italy.
| | - Monica Benincasa
- Department of Life Sciences, Via Licio Giorgieri 5, University of Trieste, 34127 Trieste, Italy.
| | - Maria Valentina Musso
- Department of Life Sciences, Via Licio Giorgieri 5, University of Trieste, 34127 Trieste, Italy.
| | - Lucija Krce
- Department of Physics, Faculty of Science, University of Split, Soba B3-18, Ruđera Boškovića 33, 21000 Split, Croatia.
| | - Ivica Aviani
- Department of Physics, Faculty of Science, University of Split, Soba B3-18, Ruđera Boškovića 33, 21000 Split, Croatia.
| | - Alberto Pallavicini
- Department of Life Sciences, Via Licio Giorgieri 5, University of Trieste, 34127 Trieste, Italy.
| | - Marco Scocchi
- Department of Life Sciences, Via Licio Giorgieri 5, University of Trieste, 34127 Trieste, Italy.
| | - Marco Gerdol
- Department of Life Sciences, Via Licio Giorgieri 5, University of Trieste, 34127 Trieste, Italy.
| | - Mario Mardirossian
- Department of Medical Sciences, University of Trieste, Laboratorio Clinica Odontostomatologica, Piazza dell'Ospitale 1, 34125 Trieste, Italy.
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Crnčević D, Krce L, Mastelić L, Maravić A, Soldo B, Aviani I, Primožič I, Odžak R, Šprung M. The mode of antibacterial action of quaternary N-benzylimidazole salts against emerging opportunistic pathogens. Bioorg Chem 2021; 112:104938. [PMID: 33933803 DOI: 10.1016/j.bioorg.2021.104938] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 04/16/2021] [Accepted: 04/19/2021] [Indexed: 12/23/2022]
Abstract
Quaternary ammonium compounds (QACs) are antimicrobial agents displaying a broad spectrum of activity due to their mechanism of action targeting the bacterial membrane. The emergence of bacterial resistance to QACs, especially in times of pandemics, requires the continuous search for new and potent QACs structures. Here we report the synthesis and biological evaluation of QACs based on imidazole derivative, N-benzylimidazole. The antimicrobial activity was tested against a range of pathogenic bacteria and fungi, both ATCC and clinical isolates, showing varying activities ranging in minimal inhibitory concentrations (MICs) from as low as 7 ng/mL. The most promising compound, N-tetradecyl derivative (BnI-14), proved to be very potent against bacterial biofilms, even at sub-MIC doses, suggesting interference with the bacterial growth and/or division process. The BnI-14 treatment induces bacterial membrane disruption, as observed by fluorescence spectroscopy and atomic force microscopy and it also binds to DNA indicating that bacterial membrane might not be the only cellular target of QACs. Most importantly, BnI-14 exhibits low toxicity to healthy human cell lines, suggesting that N-benzylimidazolium-based QACs may be promising new antimicrobial agents.
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Affiliation(s)
- Doris Crnčević
- Department of Chemistry, Faculty of Science, University of Split, Ruđera Boškovića 33, Split, Croatia.
| | - Lucija Krce
- Department of Physics, Faculty of Science, University of Split, Ruđera Boškovića 33, Split, Croatia.
| | - Linda Mastelić
- Department of Chemistry, Faculty of Science, University of Split, Ruđera Boškovića 33, Split, Croatia.
| | - Ana Maravić
- Department of Biology, Faculty of Science, University of Split, Ruđera Boškovića 33, Split, Croatia.
| | - Barbara Soldo
- Department of Chemistry, Faculty of Science, University of Split, Ruđera Boškovića 33, Split, Croatia.
| | - Ivica Aviani
- Department of Physics, Faculty of Science, University of Split, Ruđera Boškovića 33, Split, Croatia.
| | - Ines Primožič
- Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, Zagreb, Croatia.
| | - Renata Odžak
- Department of Chemistry, Faculty of Science, University of Split, Ruđera Boškovića 33, Split, Croatia.
| | - Matilda Šprung
- Department of Chemistry, Faculty of Science, University of Split, Ruđera Boškovića 33, Split, Croatia.
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Krce L, Šprung M, Rončević T, Maravić A, Čikeš Čulić V, Blažeka D, Krstulović N, Aviani I. Probing the Mode of Antibacterial Action of Silver Nanoparticles Synthesized by Laser Ablation in Water: What Fluorescence and AFM Data Tell Us. Nanomaterials (Basel) 2020; 10:nano10061040. [PMID: 32485869 PMCID: PMC7352602 DOI: 10.3390/nano10061040] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 05/26/2020] [Accepted: 05/27/2020] [Indexed: 12/17/2022]
Abstract
We aim to elucidate the mode of antibacterial action of the laser-synthesized silver colloid against Escherichia coli. Membrane integrity was studied by flow cytometry, while the strain viability of the treated culture was determined by plating. The spectrofluorometry was used to obtain the time development of the reactive oxygen species (ROS) inside the nanoparticle-treated bacterial cells. An integrated atomic force and bright-field/fluorescence microscopy system enabled the study of the cell morphology, Young modulus, viability, and integrity before and during the treatment. Upon lethal treatment, not all bacterial cells were shown to be permeabilized and have mostly kept their morphology with an indication of cell lysis. Young modulus of untreated cells was shown to be distinctly bimodal, with randomly distributed softer parts, while treated cells exhibited exponential softening of the stiffer parts in time. Silver nanoparticles and bacteria have shown a masking effect on the raw fluorescence signal through absorbance and scattering. The contribution of cellular ROS in the total fluorescence signal was resolved and it was proven that the ROS level inside the lethally treated cells is not significant. It was found that the laser-synthesized silver nanoparticles mode of antibacterial action includes reduction of the cell's Young modulus in time and subsequently the cell leakage.
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Affiliation(s)
- Lucija Krce
- Department of Physics, Faculty of Science, University of Split, Ruđera Boškovića 33, 21000 Split, Croatia;
- Correspondence:
| | - Matilda Šprung
- Department of Chemistry, Faculty of Science, University of Split, Ruđera Boškovića 33, 21000 Split, Croatia;
| | - Tomislav Rončević
- Department of Biology, Faculty of Science, University of Split, Ruđera Boškovića 33, 21000 Split, Croatia; (T.R.); (A.M.)
| | - Ana Maravić
- Department of Biology, Faculty of Science, University of Split, Ruđera Boškovića 33, 21000 Split, Croatia; (T.R.); (A.M.)
| | - Vedrana Čikeš Čulić
- Department of Medical Chemistry and Biochemistry, School of Medicine, University of Split, Šoltanska ulica 2, 21000 Split, Croatia;
| | - Damjan Blažeka
- Institute of Physics, Bijenička cesta 46, 10000 Zagreb, Croatia; (D.B.); (N.K.)
| | - Nikša Krstulović
- Institute of Physics, Bijenička cesta 46, 10000 Zagreb, Croatia; (D.B.); (N.K.)
| | - Ivica Aviani
- Department of Physics, Faculty of Science, University of Split, Ruđera Boškovića 33, 21000 Split, Croatia;
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Krce L, Šprung M, Maravić A, Umek P, Salamon K, Krstulović N, Aviani I. Bacteria Exposed to Silver Nanoparticles Synthesized by Laser Ablation in Water: Modelling E. coli Growth and Inactivation. Materials (Basel) 2020; 13:E653. [PMID: 32024125 PMCID: PMC7040691 DOI: 10.3390/ma13030653] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 01/29/2020] [Accepted: 01/30/2020] [Indexed: 12/19/2022]
Abstract
This study is aimed to better understand the bactericidal mode of action of silver nanoparticles. Here we present the production and characterization of laser-synthesized silver nanoparticles along with growth curves of bacteria treated at sub-minimal and minimal inhibitory concentrations, obtained by optical density measurements. The main effect of the treatment is the increase of the bacterial apparent lag time, which is very well described by the novel growth model as well as the entire growth curves for different concentrations. The main assumption of the model is that the treated bacteria uptake the nanoparticles and inactivate, which results in the decrease of both the nanoparticles and the bacteria concentrations. The lag assumes infinitive value for the minimal inhibitory concentration treatment. This apparent lag phase is not postponed bacterial growth. It is a dynamic state in which the bacterial growth and death rates are close in value. Our results strongly suggest that the predominant mode of antibacterial action of silver nanoparticles is the penetration inside the membrane.
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Affiliation(s)
- Lucija Krce
- Faculty of Science, Department of Physics, University of Split, Ruđera Boškovića 33, 21000 Split, Croatia;
| | - Matilda Šprung
- Faculty of Science, Department of Chemistry, University of Split, Ruđera Boškovića 33, 21000 Split, Croatia;
| | - Ana Maravić
- Faculty of Science, Department of Biology, University of Split, Ruđera Boškovića 33, 21000 Split, Croatia;
| | - Polona Umek
- Jožef Stefan Institute, Jamova cesta 39, 1000 Ljubljana, Slovenia;
| | - Krešimir Salamon
- Ruđer Bošković Institute, Bijenička cesta 54, 10 000 Zagreb, Croatia;
| | - Nikša Krstulović
- Institute of Physics, Bijenička cesta 46, 10000 Zagreb, Croatia;
| | - Ivica Aviani
- Faculty of Science, Department of Physics, University of Split, Ruđera Boškovića 33, 21000 Split, Croatia;
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Abstract
We present a simple growth model which was developed to explain Escherichia coli growth in batch culture. Optical density measurements are used to obtain E. coli growth curves for different inoculum sizes and nutrients concentrations. The model is described by two nonlinear mutually dependent differential equations that describe time evolution of bacteria and nutrients concentration. Introduction of the negative bacterium-bacterium interaction term is specific for the model and leads to the population decay. The proposed model describes entire experimental growth curves. The growth rate, as a function of initial nutrients concentration, follows the Monod function, whilst during the growth it decreases proportionally with the concentration of nutrients. The parameters in our equations can be related to the parameters of the logistic model. The proposed model can be applied to different E. coli strains and, because of the universality of the equations, might be applied to other bacterial strains.
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Affiliation(s)
- Lucija Krce
- Faculty of Science, Department of Physics, University of Split, Split, Croatia. Author to whom any correspondence should be addressed
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Maravić A, Rončević T, Krce L, Ilić N, Galić B, Čulić Čikeš V, Carev I. Halogenated boroxine dipotassium trioxohydroxytetrafluorotriborate K 2[B 3O 3F 4OH] inhibits emerging multidrug-resistant and β-lactamase-producing opportunistic pathogens. Drug Dev Ind Pharm 2019; 45:1770-1776. [PMID: 31418595 DOI: 10.1080/03639045.2019.1656736] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Halogenated boroxine dipotassium trioxohydroxytetrafluorotriborate, K2[B3O3F4OH] (boroxine) was previously shown to be very effective in inhibition of several carcinoma cell lines, including the skin cancer. Here, we investigated its antimicrobial potential by targeting the multidrug-resistant opportunistic pathogens associated with skin and wound infections. The antimicrobial testing against eleven bacterial and four fungal species revealed good activity of boroxine against pathogenic filamentous fungi Penicillium funiculosum and Aspergillus niger (MIC50 64 and 128 µg/ml), and a moderate bioactivity against the yeast Candida albicans (MIC50 512 µg/ml). Among the tested multidrug-resistant bacteria, the best antibacterial effect, stable over a 24-h period, was observed against the methicillin-resistant Staphylococcus aureus strain (MRSA) at MIC of 1024 µg/ml. The atomic force microscopy (AFM) used to investigate the morphology of S. aureus cells revealed indentations on its cell envelope after the boroxine exposure. These results show that in addition to the antitumor effect, boroxine exerts wide spectrum antimicrobial activity, thus may help preventing the development of skin and wound-related opportunistic infections.
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Affiliation(s)
- Ana Maravić
- Department of Biology, Faculty of Science, University of Split , Split , Croatia
| | - Tomislav Rončević
- Department of Physics, Faculty of Science, University of Split , Split , Croatia
| | - Lucija Krce
- Department of Physics, Faculty of Science, University of Split , Split , Croatia
| | - Nada Ilić
- Department of Physics, Faculty of Science, University of Split , Split , Croatia
| | - Borivoj Galić
- Faculty of Natural Sciences, University of Sarajevo , Sarajevo , Bosnia And Herzegovina
| | - Vedrana Čulić Čikeš
- Department of Medicinal Chemistry and Biochemistry, Medical School, University of Split , Split , Croatia
| | - Ivana Carev
- Department of Biochemistry, Faculty of Chemistry and Engineering, University of Split , Split , Croatia
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Rončević T, Vukičević D, Krce L, Benincasa M, Aviani I, Maravić A, Tossi A. Selection and redesign for high selectivity of membrane-active antimicrobial peptides from a dedicated sequence/function database. Biochimica et Biophysica Acta (BBA) - Biomembranes 2019; 1861:827-834. [DOI: 10.1016/j.bbamem.2019.01.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 01/25/2019] [Accepted: 01/29/2019] [Indexed: 12/19/2022]
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Bazina L, Maravić A, Krce L, Soldo B, Odžak R, Popović VB, Aviani I, Primožič I, Šprung M. Discovery of novel quaternary ammonium compounds based on quinuclidine-3-ol as new potential antimicrobial candidates. Eur J Med Chem 2019; 163:626-635. [DOI: 10.1016/j.ejmech.2018.12.023] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 12/06/2018] [Accepted: 12/11/2018] [Indexed: 01/18/2023]
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Rončević T, Vukičević D, Ilić N, Krce L, Gajski G, Tonkić M, Goić-Barišić I, Zoranić L, Sonavane Y, Benincasa M, Juretić D, Maravić A, Tossi A. Antibacterial Activity Affected by the Conformational Flexibility in Glycine–Lysine Based α-Helical Antimicrobial Peptides. J Med Chem 2018; 61:2924-2936. [DOI: 10.1021/acs.jmedchem.7b01831] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Tomislav Rončević
- Department of Physics, Faculty of Science, University of Split, 21000 Split, Croatia
| | - Damir Vukičević
- Department of Mathematics, Faculty of Science, University of Split, 21000 Split, Croatia
| | - Nada Ilić
- Department of Physics, Faculty of Science, University of Split, 21000 Split, Croatia
| | - Lucija Krce
- Department of Physics, Faculty of Science, University of Split, 21000 Split, Croatia
| | - Goran Gajski
- Mutagenesis Unit, Institute for Medical Research and Occupational Health, 10000 Zagreb, Croatia
| | - Marija Tonkić
- Department of Clinical Microbiology, University Hospital of Split, 21000 Split, Croatia
- School of Medicine, University of Split, 21000 Split, Croatia
| | - Ivana Goić-Barišić
- Department of Clinical Microbiology, University Hospital of Split, 21000 Split, Croatia
- School of Medicine, University of Split, 21000 Split, Croatia
| | - Larisa Zoranić
- Department of Physics, Faculty of Science, University of Split, 21000 Split, Croatia
| | - Yogesh Sonavane
- Department of Physics, Faculty of Science, University of Split, 21000 Split, Croatia
| | - Monica Benincasa
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy
| | - Davor Juretić
- Department of Physics, Faculty of Science, University of Split, 21000 Split, Croatia
- Mediterranean Institute for Life Sciences, 21000 Split, Croatia
| | - Ana Maravić
- Department of Biology, Faculty of Science, University of Split, Ruđera Boškovića 33, 21000 Split, Croatia
| | - Alessandro Tossi
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy
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