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Rainsford P, Rylandsholm FG, Jakubec M, Silk M, Juskewitz E, Ericson JU, Svendsen JS, Engh RA, Isaksson J. Label-free measurement of antimicrobial peptide interactions with lipid vesicles and nanodiscs using microscale thermophoresis. Sci Rep 2023; 13:12619. [PMID: 37537266 PMCID: PMC10400562 DOI: 10.1038/s41598-023-39785-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Accepted: 07/31/2023] [Indexed: 08/05/2023] Open
Abstract
One strategy to combat antimicrobial resistance is the discovery of new classes of antibiotics. Most antibiotics will at some point interact with the bacterial membrane to either interfere with its integrity or to cross it. Reliable and efficient tools for determining the dissociation constant for membrane binding (KD) and the partitioning coefficient between the aqueous- and membrane phases (KP) are therefore important tools for discovering and optimizing antimicrobial hits. Here we demonstrate that microscale thermophoresis (MST) can be used for label-free measurement of KD by utilising the intrinsic fluorescence of tryptophan and thereby removing the need for chromophore labelling. As proof of principle, we have used the method to measure the binding of a set of small cyclic AMPs to large unilamellar vesicles (LUVs) and two types of lipid nanodiscs assembled by styrene maleic acid (SMA) and quaternary ammonium SMA (SMA-QA). The measured KD values correlate well with the corresponding measurements using surface plasmon resonance (SPR), also broadly reflecting the tested AMPs' minimal inhibition concentration (MIC) towards S. aureus and E. coli. We conclude that MST is a promising method for fast and cost-efficient detection of peptide-lipid interactions or mapping of sample conditions in preparation for more advanced studies that rely on expensive sample preparation, labelling and/or instrument time.
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Affiliation(s)
- Philip Rainsford
- Department of Chemistry, Faculty of Science and Technology, UiT the Arctic University of Norway, 9019, Tromsø, Norway
| | - Fredrik G Rylandsholm
- Department of Chemistry, Faculty of Science and Technology, UiT the Arctic University of Norway, 9019, Tromsø, Norway
| | - Martin Jakubec
- Department of Chemistry, Faculty of Science and Technology, UiT the Arctic University of Norway, 9019, Tromsø, Norway
| | - Mitchell Silk
- Department of Chemistry, Faculty of Science and Technology, UiT the Arctic University of Norway, 9019, Tromsø, Norway
| | - Eric Juskewitz
- Research Group for Host Microbe Interactions, Department of Medical Biology, Faculty of Health Sciences, UiT the Arctic University of Norway, 9019, Tromsø, Norway
| | - Johanna U Ericson
- Research Group for Host Microbe Interactions, Department of Medical Biology, Faculty of Health Sciences, UiT the Arctic University of Norway, 9019, Tromsø, Norway
| | - John-Sigurd Svendsen
- Department of Chemistry, Faculty of Science and Technology, UiT the Arctic University of Norway, 9019, Tromsø, Norway
| | - Richard A Engh
- Department of Chemistry, Faculty of Science and Technology, UiT the Arctic University of Norway, 9019, Tromsø, Norway
| | - Johan Isaksson
- Department of Chemistry, Faculty of Science and Technology, UiT the Arctic University of Norway, 9019, Tromsø, Norway.
- Natural Products and Medicinal Chemistry, Department of Pharmacy, Faculty of Health Sciences, UiT the Arctic University of Norway, 9037, Tromsø, Norway.
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Wang Q, Xu Y, Hu J. Intracellular mechanism of antimicrobial peptide HJH-3 against Salmonella pullorum. RSC Adv 2022; 12:14485-14491. [PMID: 35702236 PMCID: PMC9103801 DOI: 10.1039/d2ra01363k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 05/05/2022] [Indexed: 12/05/2022] Open
Abstract
To explore the potential intracellular mechanism of the antimicrobial peptide HJH-3 in killing Salmonella, a DNA blocking test and scanning electron microscopy (SEM) were used to determine the ability of the peptide to bind bacterial DNA in vitro. Laser confocal analysis and electron microscopy were used to observe the binding of antimicrobial peptide HJH-3 and Salmonella DNA, and flow cytometry was used to analyze the effect of antimicrobial peptides on cell division in vivo. The results showed that HJH-3 can bind to DNA to block the diffusion and migration of DNA in agarose gel. Laser confocal microscopy revealed that antimicrobial peptide HJH-3 penetrated the bacterial cell membrane and bound with bacterial DNA. Transmission electron microscopy showed that antimicrobial peptide HJH-3 aggregated in the nucleoid of Salmonella cells, and through a channel in the membrane destroyed by the antimicrobial peptide, DNA and other intracellular contents were excreted, and polymerized DNA was fragmented. The results of the flow cytometry analysis confirmed that the death rate of Salmonella increased significantly after exposure to antimicrobial peptide HJH-3 and increased with increasing antimicrobial peptide concentration. These results suggest that AMP HJH-3 may be a candidate antimicrobial agent to treat infectious diseases caused by Salmonella pullorum. To explore the potential intracellular mechanism of the antimicrobial peptide HJH-3 in killing Salmonella, a DNA blocking test and scanning electron microscopy (SEM) were used to determine the ability of the peptide to bind bacterial DNA in vitro.![]()
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Affiliation(s)
- Qing Wang
- College of Animal Science and Veterinary Medicine, Henan Institute of Science and Technology, Xinxiang 453003, China
| | - Yanzhao Xu
- College of Animal Science and Veterinary Medicine, Henan Institute of Science and Technology, Xinxiang 453003, China
| | - Jianhe Hu
- College of Animal Science and Veterinary Medicine, Henan Institute of Science and Technology, Xinxiang 453003, China
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Kuhn B, Picollo F, Carabelli V, Rispoli G. Advanced real-time recordings of neuronal activity with tailored patch pipettes, diamond multi-electrode arrays and electrochromic voltage-sensitive dyes. Pflugers Arch 2020; 473:15-36. [PMID: 33047171 PMCID: PMC7782438 DOI: 10.1007/s00424-020-02472-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 09/29/2020] [Accepted: 10/02/2020] [Indexed: 12/03/2022]
Abstract
To understand the working principles of the nervous system is key to figure out its electrical activity and how this activity spreads along the neuronal network. It is therefore crucial to develop advanced techniques aimed to record in real time the electrical activity, from compartments of single neurons to populations of neurons, to understand how higher functions emerge from coordinated activity. To record from single neurons, a technique will be presented to fabricate patch pipettes able to seal on any membrane with a single glass type and whose shanks can be widened as desired. This dramatically reduces access resistance during whole-cell recording allowing fast intracellular and, if required, extracellular perfusion. To simultaneously record from many neurons, biocompatible probes will be described employing multi-electrodes made with novel technologies, based on diamond substrates. These probes also allow to synchronously record exocytosis and neuronal excitability and to stimulate neurons. Finally, to achieve even higher spatial resolution, it will be shown how voltage imaging, employing fast voltage-sensitive dyes and two-photon microscopy, is able to sample voltage oscillations in the brain spatially resolved and voltage changes in dendrites of single neurons at millisecond and micrometre resolution in awake animals.
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Affiliation(s)
- Bernd Kuhn
- Optical Neuroimaging Unit, OIST Graduate University, 1919-1 Tancha, Onna-son, Okinawa, Japan
| | - Federico Picollo
- Department of Physics, NIS Interdepartmental Centre, University of Torino and Italian Institute of Nuclear Physics, via Giuria 1, 10125, Torino, Italy
| | - Valentina Carabelli
- Department of Drug and Science Technology, NIS Interdepartmental Centre, University of Torino, Corso Raffaello 30, 10125, Torino, Italy
| | - Giorgio Rispoli
- Department of Biomedical and Specialist Surgical Sciences, University of Ferrara, Via Luigi Borsari 46, 44121, Ferrara, Italy.
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Clark GC, Casewell NR, Elliott CT, Harvey AL, Jamieson AG, Strong PN, Turner AD. Friends or Foes? Emerging Impacts of Biological Toxins. Trends Biochem Sci 2019; 44:365-379. [PMID: 30651181 DOI: 10.1016/j.tibs.2018.12.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 11/21/2018] [Accepted: 12/07/2018] [Indexed: 12/19/2022]
Abstract
Toxins are substances produced from biological sources (e.g., animal, plants, microorganisms) that have deleterious effects on a living organism. Despite the obvious health concerns of being exposed to toxins, they are having substantial positive impacts in a number of industrial sectors. Several toxin-derived products are approved for clinical, veterinary, or agrochemical uses. This review sets out the case for toxins as 'friends' that are providing the basis of novel medicines, insecticides, and even nucleic acid sequencing technologies. We also discuss emerging toxins ('foes') that are becoming increasingly prevalent in a range of contexts through climate change and the globalisation of food supply chains and that ultimately pose a risk to health.
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Affiliation(s)
- Graeme C Clark
- CBR Division, Defence Science & Technology Laboratory, DSTL - Porton Down, Salisbury, Wiltshire, SP4 0JQ, UK.
| | - Nicholas R Casewell
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Christopher T Elliott
- Institute for Global Food Security, School of Biological Sciences, Queen's University, Belfast, 97 Lisburn Road, Belfast, BT9 7BL, UK
| | - Alan L Harvey
- Strathclyde Institute of Pharmacy & Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, Glasgow, G4 0RE, UK
| | - Andrew G Jamieson
- School of Chemistry, Joseph Black Building, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Peter N Strong
- Biomolecular Research Centre, Department of Biosciences and Chemistry, Sheffield Hallam University, Sheffield, S1 1WB, UK
| | - Andrew D Turner
- Food Safety Group, Cefas, Barrack Road, The Nothe, Weymouth, Dorset DT4 8UB, UK
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