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Narayanan T. Recent advances in synchrotron scattering methods for probing the structure and dynamics of colloids. Adv Colloid Interface Sci 2024; 325:103114. [PMID: 38452431 DOI: 10.1016/j.cis.2024.103114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 02/07/2024] [Accepted: 02/14/2024] [Indexed: 03/09/2024]
Abstract
Recent progress in synchrotron based X-ray scattering methods applied to colloid science is reviewed. An important figure of merit of these techniques is that they enable in situ investigations of colloidal systems under the desired thermophysical and rheological conditions. An ensemble averaged simultaneous structural and dynamical information can be derived albeit in reciprocal space. Significant improvements in X-ray source brilliance and advances in detector technology have overcome some of the limitations in the past. Notably coherent X-ray scattering techniques have become more competitive and they provide complementary information to laboratory based real space methods. For a system with sufficient scattering contrast, size ranges from nm to several μm and time scales down to μs are now amenable to X-ray scattering investigations. A wide variety of sample environments can be combined with scattering experiments further enriching the science that could be pursued by means of advanced X-ray scattering instruments. Some of these recent progresses are illustrated via representative examples. To derive quantitative information from the scattering data, rigorous data analysis or modeling is required. Development of powerful computational tools including the use of artificial intelligence have become the emerging trend.
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Jennings J, Ašćerić D, Semeraro EF, Lohner K, Malanovic N, Pabst G. Combinatorial Screening of Cationic Lipidoids Reveals How Molecular Conformation Affects Membrane-Targeting Antimicrobial Activity. ACS APPLIED MATERIALS & INTERFACES 2023; 15:40178-40190. [PMID: 37602460 PMCID: PMC10472336 DOI: 10.1021/acsami.3c05481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 08/04/2023] [Indexed: 08/22/2023]
Abstract
The search for next-generation antibacterial compounds that overcome the development of resistance can be facilitated by identifying how to target the cell membrane of bacteria. Understanding the key molecular features that enable interactions with lipids and lead to membrane disruption is therefore crucial. Here, we employ a library of lipid-like compounds (lipidoids) comprising modular structures with tunable hydrophobic and hydrophilic architecture to shed light on how the chemical functionality and molecular shape of synthetic amphiphilic compounds determine their activity against bacterial membranes. Synthesized from combinations of 8 different polyamines as headgroups and 13 acrylates as tails, 104 different lipidoids are tested for activity against a model Gram-positive bacterial strain (Bacillus subtilis). Results from the combinatorial screening assay show that lipidoids with the most potent antimicrobial properties (down to 2 μM) have intermediate tail hydrophobicity (i.e., c log P values between 3 and 4) and lower headgroup charge density (i.e., longer spacers between charged amines). However, the most important factor appeared to be the ability of a lipidoid to self-assemble into an inverse hexagonal liquid crystalline phase, as observed by small-angle X-ray scattering (SAXS) analysis. The lipidoids active at lowest concentrations, which induced the most significant membrane damage during propidium iodide (PI) permeabilization assays, were those that aggregated into highly curved inverse hexagonal liquid crystal phases. These observations suggest that the introduction of strong curvature stress into the membrane is one way to maximize membrane disruption and lipidoid antimicrobial activity. Lipidoids that demonstrated the ability to furnish this phase consisted of either (i) branched or linear headgroups with shorter linear tails or (ii) cyclic headgroups with 4 bulky nonlinear tails. On the contrary, lipidoids previously observed to adopt disc-like conformations that pack into bicontinuous cubic phases were significantly less effective against B. subtilis. The discovery of these structure-property relationships demonstrates that it is not simply a balance of hydrophobic and hydrophilic moieties that govern membrane-active antibacterial activity, but also their intrinsic curvature and collective behavior.
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Affiliation(s)
- James Jennings
- Institute
of Molecular Biosciences, University of
Graz, NAWI Graz, 8010 Graz, Austria
- Field
of Excellence BioHealth, University of Graz, 8010 Graz, Austria
| | - Dunja Ašćerić
- Institute
of Molecular Biosciences, University of
Graz, NAWI Graz, 8010 Graz, Austria
- Field
of Excellence BioHealth, University of Graz, 8010 Graz, Austria
| | - Enrico Federico Semeraro
- Institute
of Molecular Biosciences, University of
Graz, NAWI Graz, 8010 Graz, Austria
- Field
of Excellence BioHealth, University of Graz, 8010 Graz, Austria
| | - Karl Lohner
- Institute
of Molecular Biosciences, University of
Graz, NAWI Graz, 8010 Graz, Austria
- Field
of Excellence BioHealth, University of Graz, 8010 Graz, Austria
| | - Nermina Malanovic
- Institute
of Molecular Biosciences, University of
Graz, NAWI Graz, 8010 Graz, Austria
- Field
of Excellence BioHealth, University of Graz, 8010 Graz, Austria
| | - Georg Pabst
- Institute
of Molecular Biosciences, University of
Graz, NAWI Graz, 8010 Graz, Austria
- Field
of Excellence BioHealth, University of Graz, 8010 Graz, Austria
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Hilpert K, Rumancev C, Gani J, Collis DWP, Lopez-Perez PM, Garamus VM, Mikut R, Rosenhahn A. Can BioSAXS detect ultrastructural changes of antifungal compounds in Candida albicans?-an exploratory study. Front Pharmacol 2023; 14:1141785. [PMID: 37533629 PMCID: PMC10393279 DOI: 10.3389/fphar.2023.1141785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 07/06/2023] [Indexed: 08/04/2023] Open
Abstract
The opportunistic yeast Candida albicans is the most common cause of candidiasis. With only four classes of antifungal drugs on the market, resistance is becoming a problem in the treatment of fungal infections, especially in immunocompromised patients. The development of novel antifungal drugs with different modes of action is urgent. In 2016, we developed a groundbreaking new medium-throughput method to distinguish the effects of antibacterial agents. Using small-angle X-ray scattering for biological samples (BioSAXS), it is now possible to screen hundreds of new antibacterial compounds and select those with the highest probability for a novel mode of action. However, yeast (eukaryotic) cells are highly structured compared to bacteria. The fundamental question to answer was if the ultrastructural changes induced by the action of an antifungal drug can be detected even when most structures in the cell stay unchanged. In this exploratory work, BioSAXS was used to measure the ultrastructural changes of C. albicans that were directly or indirectly induced by antifungal compounds. For this, the well-characterized antifungal drug Flucytosine was used. BioSAXS measurements were performed on the synchrotron P12 BioSAXS beamline, EMBL (DESY, Hamburg) on treated and untreated yeast C. albicans. BioSAXS curves were analysed using principal component analysis (PCA). The PCA showed that Flucytosine-treated and untreated yeast were separated. Based on that success further measurements were performed on five antifungal peptides {1. Cecropin A-melittin hybrid [CA (1-7) M (2-9)], KWKLFKKIGAVLKVL; 2. Lasioglossin LL-III, VNWKKILGKIIKVVK; 3. Mastoparan M, INLKAIAALAKKLL; 4. Bmkn2, FIGAIARLLSKIFGKR; and 5. optP7, KRRVRWIIW}. The ultrastructural changes of C. albicans indicate that the peptides may have different modes of action compared to Flucytosine as well as to each other, except for the Cecropin A-melittin hybrid [CA (1-7) M (2-9)] and optP7, showing very similar effects on C. albicans. This very first study demonstrates that BioSAXS shows promise to be used for antifungal drug development. However, this first study has limitations and further experiments are necessary to establish this application.
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Affiliation(s)
- Kai Hilpert
- Institute of Infection and Immunology, St. George’s, University of London (SGUL), London, United Kingdom
| | - Christoph Rumancev
- Laboratory Analytical Chemistry—Biointerfaces, Ruhr-University Bochum, Bochum, Germany
| | - Jurnorain Gani
- Institute of Infection and Immunology, St. George’s, University of London (SGUL), London, United Kingdom
| | | | | | | | - Ralf Mikut
- Institute for Automation and Applied Informatics (IAI), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Axel Rosenhahn
- Laboratory Analytical Chemistry—Biointerfaces, Ruhr-University Bochum, Bochum, Germany
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Troiano C, De Ninno A, Casciaro B, Riccitelli F, Park Y, Businaro L, Massoud R, Mangoni ML, Bisegna P, Stella L, Caselli F. Rapid Assessment of Susceptibility of Bacteria and Erythrocytes to Antimicrobial Peptides by Single-Cell Impedance Cytometry. ACS Sens 2023. [PMID: 37421371 PMCID: PMC10391704 DOI: 10.1021/acssensors.3c00256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/10/2023]
Abstract
Antimicrobial peptides (AMPs) represent a promising class of compounds to fight antibiotic-resistant infections. In most cases, they kill bacteria by making their membrane permeable and therefore exhibit low propensity to induce bacterial resistance. In addition, they are often selective, killing bacteria at concentrations lower than those at which they are toxic to the host. However, clinical applications of AMPs are hindered by a limited understanding of their interactions with bacteria and human cells. Standard susceptibility testing methods are based on the analysis of the growth of a bacterial population and therefore require several hours. Moreover, different assays are required to assess the toxicity to host cells. In this work, we propose the use of microfluidic impedance cytometry to explore the action of AMPs on both bacteria and host cells in a rapid manner and with single-cell resolution. Impedance measurements are particularly well-suited to detect the effects of AMPs on bacteria, due to the fact that the mechanism of action involves perturbation of the permeability of cell membranes. We show that the electrical signatures of Bacillus megaterium cells and human red blood cells (RBCs) reflect the action of a representative antimicrobial peptide, DNS-PMAP23. In particular, the impedance phase at high frequency (e.g., 11 or 20 MHz) is a reliable label-free metric for monitoring DNS-PMAP23 bactericidal activity and toxicity to RBCs. The impedance-based characterization is validated by comparison with standard antibacterial activity assays and absorbance-based hemolytic activity assays. Furthermore, we demonstrate the applicability of the technique to a mixed sample of B. megaterium cells and RBCs, which paves the way to study AMP selectivity for bacterial versus eukaryotic cells in the presence of both cell types.
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Affiliation(s)
- Cassandra Troiano
- Department of Chemical Science and Technologies, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Adele De Ninno
- Institute for Photonics and Nanotechnologies, Italian National Research Council, 00133 Rome, Italy
| | - Bruno Casciaro
- Laboratory affiliated to Pasteur Italia-Fondazione Cenci Bolognetti, Department of Biochemical Sciences "A. Rossi Fanelli", Sapienza University of Rome, 00185 Rome, Italy
| | - Francesco Riccitelli
- Department of Chemical Science and Technologies, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Yoonkyung Park
- Department of Biomedical Science, College of Natural science, Chosun University, Gwangju 61452, Republic of Korea
| | - Luca Businaro
- Institute for Photonics and Nanotechnologies, Italian National Research Council, 00133 Rome, Italy
| | - Renato Massoud
- Department of Experimental Medicine, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Maria Luisa Mangoni
- Laboratory affiliated to Pasteur Italia-Fondazione Cenci Bolognetti, Department of Biochemical Sciences "A. Rossi Fanelli", Sapienza University of Rome, 00185 Rome, Italy
| | - Paolo Bisegna
- Department of Civil Engineering and Computer Science, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Lorenzo Stella
- Department of Chemical Science and Technologies, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Federica Caselli
- Department of Civil Engineering and Computer Science, University of Rome Tor Vergata, 00133 Rome, Italy
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Wang CB, Yan X, Wang GH, Liu WQ, Wang Y, Hao DF, Liu HM, Zhang M. NKHs27, a sevenband grouper NK-Lysin peptide that possesses immunoregulatory and antimicrobial activity. FISH & SHELLFISH IMMUNOLOGY 2023; 136:108715. [PMID: 37001746 DOI: 10.1016/j.fsi.2023.108715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Revised: 03/22/2023] [Accepted: 03/26/2023] [Indexed: 06/19/2023]
Abstract
As an effective and broad-spectrum antimicrobial peptide, NK-Lysin is attracted more and more attention at present. However, the functions and action mechanism of NK-Lysin peptides are still not comprehensive enough at present. In this study, a sevenband grouper (Hyporthodus septemfasciatus) NK-Lysin peptide, NKHs27, was identified and synthesized, and its biological functions were studied. The results indicated that NKHs27 shares 44.44%∼88.89% overall sequence identities with other teleost NK-Lysin peptides. The following antibacterial activity assay exhibited that NKHs27 was active against both Gram-negative and Gram-positive bacteria, including Staphylococcus aureus, Listonella anguillarum, Vibrio parahaemolyticus and Vibrio vulnificus. Additionally, NKHs27 showed a synergistic effect when it was combined with rifampicin or erythromycin. In the process of interaction with the L. anguillarum cells, NKHs27 changed the cell membrane permeability and retained its morphological integrity, then penetrated into the cytoplasm to act on genomic DNA or total RNA. Then, in vitro studies showed that NKHs27 could enhance the respiratory burst ability of macrophages and upregulate immune-related genes expression in it. Moreover, NKHs27 incubation improved the proliferation of peripheral blood leukocytes significantly. Finally, in vivo studies showed that administration of NKHs27 prior to bacterial infection significantly reduced pathogen dissemination and replication in tissues. In summary, these results provide new insights into the function of NK-Lysin peptides in teleost and support that NKHs27, as a novel broad-spectrum antibacterial peptide, has potential applications in aquaculture against pathogenic infections.
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Affiliation(s)
- Chang-Biao Wang
- School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, Shandong Province, 266109, China
| | - Xue Yan
- School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, Shandong Province, 266109, China
| | - Guang-Hua Wang
- School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, Shandong Province, 266109, China
| | - Wen-Qing Liu
- School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, Shandong Province, 266109, China
| | - Yue Wang
- School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, Shandong Province, 266109, China
| | - Dong-Fang Hao
- School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, Shandong Province, 266109, China
| | - Hong-Mei Liu
- School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, Shandong Province, 266109, China
| | - Min Zhang
- School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, Shandong Province, 266109, China; Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, Shandong Province, 266109, China.
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6
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Vejzovic D, Iftic A, Ön A, Semeraro EF, Malanovic N. Octenidine's Efficacy: A Matter of Interpretation or the Influence of Experimental Setups? Antibiotics (Basel) 2022; 11:1665. [PMID: 36421309 PMCID: PMC9686575 DOI: 10.3390/antibiotics11111665] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 11/14/2022] [Accepted: 11/15/2022] [Indexed: 07/30/2023] Open
Abstract
With its broad antimicrobial spectrum and non-specific mode of action via membrane disruption, any resistance to octenidine (OCT) seems unlikely and has not been observed in clinical settings so far. In this study, we aimed to investigate the efficacy of OCT against Escherichia coli and mutants lacking specific lipid head groups which, due to altered membrane properties, might be the root cause for resistance development of membrane-active compounds. Furthermore, we aimed to test its efficacy under different experimental conditions including different solvents for OCT, bacterial concentration and methods for analysis. Our primary goal was to estimate how many OCT molecules are needed to kill one bacterium. We performed susceptibility assays by observing bacterial growth behavior, using a Bioscreen in an analogous manner for every condition. The growth curves were recorded for 20 h at 420-580 nm in presence of different OCT concentrations and were used to assess the inhibitory concentrations (IC100%) for OCT. Bacterial concentrations given in cell numbers were determined, followed by Bioscreen measurement by manual colony counting on agar plates and QUANTOMTM cell staining. This indicated a significant variance between both methods, which influenced IC100% of OCT, especially when used at low doses. The binding capacity of OCT to E. coli was investigated by measuring UV-absorbance of OCT exposed to bacteria and a common thermodynamic framework based on Bioscreen measurements. Results showed that OCT's antimicrobial activity in E. coli is not affected by changes at the membrane level but strongly dependent on experimental settings in respect to solvents and applied bacterial counts. More OCT was required when the active was dissolved in phosphate or Hepes buffers instead of water and when higher bacterial concentration was used. Furthermore, binding studies revealed that 107-108 OCT molecules bind to bacteria, which is necessary for the saturation of the bacterial surface to initiate the killing cascade. Our results clearly demonstrate that in vitro data, depending on the applied materials and the methods for determination of IC100%, can easily be misinterpreted as reduced bacterial susceptibility towards OCT.
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Affiliation(s)
- Djenana Vejzovic
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | - Azra Iftic
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | - Ayse Ön
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | - Enrico F. Semeraro
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
- Field of Excellence BioHealth, University of Graz, 8010 Graz, Austria
- Bio TechMed Graz, 8010 Graz, Austria
| | - Nermina Malanovic
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
- Field of Excellence BioHealth, University of Graz, 8010 Graz, Austria
- Bio TechMed Graz, 8010 Graz, Austria
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7
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Takahashi H, Sovadinova I, Yasuhara K, Vemparala S, Caputo GA, Kuroda K. Biomimetic antimicrobial polymers—Design, characterization, antimicrobial, and novel applications. WIRES NANOMEDICINE AND NANOBIOTECHNOLOGY 2022; 15:e1866. [PMID: 36300561 DOI: 10.1002/wnan.1866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Revised: 09/15/2022] [Accepted: 09/27/2022] [Indexed: 11/05/2022]
Abstract
Biomimetic antimicrobial polymers have been an area of great interest as the need for novel antimicrobial compounds grows due to the development of resistance. These polymers were designed and developed to mimic naturally occurring antimicrobial peptides in both physicochemical composition and mechanism of action. These antimicrobial peptide mimetic polymers have been extensively investigated using chemical, biophysical, microbiological, and computational approaches to gain a deeper understanding of the molecular interactions that drive function. These studies have helped inform SARs, mechanism of action, and general physicochemical factors that influence the activity and properties of antimicrobial polymers. However, there are still lingering questions in this field regarding 3D structural patterning, bioavailability, and applicability to alternative targets. In this review, we present a perspective on the development and characterization of several antimicrobial polymers and discuss novel applications of these molecules emerging in the field. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease.
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Affiliation(s)
- Haruko Takahashi
- Graduate School of Integrated Sciences for Life Hiroshima University Higashi‐Hiroshima Hiroshima Japan
| | - Iva Sovadinova
- RECETOX, Faculty of Science Masaryk University Brno Czech Republic
| | - Kazuma Yasuhara
- Division of Materials Science, Graduate School of Science and Technology Nara Institute of Science and Technology Nara Japan
- Center for Digital Green‐Innovation Nara Institute of Science and Technology Nara Japan
| | - Satyavani Vemparala
- The Institute of Mathematical Sciences CIT Campus Chennai India
- Homi Bhabha National Institute Training School Complex Mumbai India
| | - Gregory A. Caputo
- Department of Chemistry & Biochemistry Rowan University Glassboro New Jersey USA
| | - Kenichi Kuroda
- Department of Biologic and Materials Sciences & Prosthodontics, School of Dentistry University of Michigan Ann Arbor Michigan USA
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