1
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Langer MK, Rahman A, Dey H, Anderssen T, Blencke HM, Haug T, Stensvåg K, Strøm MB, Bayer A. Investigation of tetrasubstituted heterocycles reveals hydantoins as a promising scaffold for development of novel antimicrobials with membranolytic properties. Eur J Med Chem 2023; 249:115147. [PMID: 36739750 DOI: 10.1016/j.ejmech.2023.115147] [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: 11/13/2022] [Revised: 12/19/2022] [Accepted: 01/21/2023] [Indexed: 01/26/2023]
Abstract
Mimics of antimicrobial peptides (AMPs) have been proposed as a promising class of antimicrobial agents. We report the analysis of five tetrasubstituted, cationic, amphipathic heterocycles as potential AMP mimics. The analysis showed that the heterocyclic scaffold had a strong influence on the haemolytic activity of the compounds, and the hydantoin scaffold was identified as a promising template for drug lead development. Subsequently, a total of 20 hydantoin derivatives were studied for their antimicrobial potency and haemolytic activity. We found 19 of these derivatives to have very low haemolytic toxicity and identified three lead structures, 2dA, 6cG, and 6dG with very promising broad-spectrum antimicrobial activity. Lead structure 6dG displayed minimum inhibitory concentration (MIC) values as low as 1 μg/mL against Gram-positive bacteria and 4-16 μg/mL against Gram-negative bacteria. Initial mode of action (MoA) studies performed on the amine derivative 6cG, utilizing a luciferase-based biosensor assay, suggested a strong membrane disrupting effect on the outer and inner membrane of Escherichia coli. Our findings show that the physical properties and structural arrangement induced by the heterocyclic scaffolds are important factors in the design of AMP mimics.
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Affiliation(s)
- Manuel K Langer
- Department of Chemistry, UiT - The Arctic University of Norway, NO-9037, Tromsø, Norway
| | - Ataur Rahman
- The Norwegian College of Fishery Science, Faculty of Biosciences, Fisheries and Economics, UiT - The Arctic University of Norway, NO-9037, Tromsø, Norway
| | - Hymonti Dey
- The Norwegian College of Fishery Science, Faculty of Biosciences, Fisheries and Economics, UiT - The Arctic University of Norway, NO-9037, Tromsø, Norway
| | - Trude Anderssen
- Department of Pharmacy, Faculty of Health Sciences, UiT - The Arctic University of Norway, NO-9037, Tromsø, Norway
| | - Hans-Matti Blencke
- The Norwegian College of Fishery Science, Faculty of Biosciences, Fisheries and Economics, UiT - The Arctic University of Norway, NO-9037, Tromsø, Norway
| | - Tor Haug
- The Norwegian College of Fishery Science, Faculty of Biosciences, Fisheries and Economics, UiT - The Arctic University of Norway, NO-9037, Tromsø, Norway
| | - Klara Stensvåg
- The Norwegian College of Fishery Science, Faculty of Biosciences, Fisheries and Economics, UiT - The Arctic University of Norway, NO-9037, Tromsø, Norway
| | - Morten B Strøm
- Department of Pharmacy, Faculty of Health Sciences, UiT - The Arctic University of Norway, NO-9037, Tromsø, Norway.
| | - Annette Bayer
- Department of Chemistry, UiT - The Arctic University of Norway, NO-9037, Tromsø, Norway.
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2
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Efficacy of natural antimicrobial peptides versus peptidomimetic analogues: a systematic review. Future Med Chem 2022; 14:1899-1921. [PMID: 36421051 DOI: 10.4155/fmc-2022-0160] [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: 11/25/2022] Open
Abstract
Aims: This systematic review was carried out to determine whether synthetic peptidomimetics exhibit significant advantages over antimicrobial peptides in terms of in vitro potency. Structural features - molecular weight, charge and length - were examined for correlations with activity. Methods: Original research articles reporting minimum inhibitory concentration values against Escherichia coli, indexed until 31 December 2020, were searched in PubMed/ScienceDirect/Google Scholar and evaluated using mixed-effects models. Results: In vitro antimicrobial activity of peptidomimetics resembled that of antimicrobial peptides. Net charge significantly affected minimum inhibitory concentration values (p < 0.001) with a trend of 4.6% decrease for increments in charge by +1. Conclusion: AMPs and antibacterial peptidomimetics exhibit similar potencies, providing an opportunity to exploit the advantageous stability and bioavailability typically associated with peptidomimetics.
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3
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Synthesis and Antimicrobial Activity of Short Analogues of the Marine Antimicrobial Peptide Turgencin A: Effects of SAR Optimizations, Cys-Cys Cyclization and Lipopeptide Modifications. Int J Mol Sci 2022; 23:ijms232213844. [PMID: 36430320 PMCID: PMC9696794 DOI: 10.3390/ijms232213844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 11/08/2022] [Indexed: 11/12/2022] Open
Abstract
We have synthesised short analogues of the marine antimicrobial peptide Turgencin A from the colonial Arctic ascidian Synoicum turgens. In this study, we focused on a central, cationic 12-residue Cys-Cys loop region within the sequence. Modified (tryptophan- and arginine-enriched) linear peptides were compared with Cys-Cys cyclic derivatives, and both linear and Cys-cyclic peptides were N-terminally acylated with octanoic acid (C8), decanoic acid (C10) or dodecanoic acid (C12). The highest antimicrobial potency was achieved by introducing dodecanoic acid to a cyclic Turgencin A analogue with low intrinsic hydrophobicity, and by introducing octanoic acid to a cyclic analogue displaying a higher intrinsic hydrophobicity. Among all tested synthetic Turgencin A lipopeptide analogues, the most promising candidates regarding both antimicrobial and haemolytic activity were C12-cTurg-1 and C8-cTurg-2. These optimized cyclic lipopeptides displayed minimum inhibitory concentrations of 4 µg/mL against Staphylococcus aureus, Escherichia coli and the fungus Rhodothorula sp. Mode of action studies on bacteria showed a rapid membrane disruption and bactericidal effect of the cyclic lipopeptides. Haemolytic activity against human erythrocytes was low, indicating favorable selective targeting of bacterial cells.
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4
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Wester A, Björkling F, Franzyk H. Evaluation of 1 H-Triazole-1-[ N, N'-Bis( tert-butoxycarbonyl)]carboxamidine in Solution-Phase and On-Resin Guanidinylation. J Org Chem 2021; 86:14371-14380. [PMID: 34661410 DOI: 10.1021/acs.joc.1c00994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Several guanidines and guanidinylated peptides have substantial potential as therapeutics, but efficient guanidinylation reagents are vital for easy access to these compounds. Presently, pyrazole-1-carboxamidine type reagents are commonly used in the transformations of amines into corresponding guanidines. Here, we report a comparative study of the utility of 1H-triazole-1-[N,N'-bis(tert-butoxycarbonyl)]carboxamidine, which was synthesized in two steps and readily upscaled to gram amounts. It exhibited excellent performance in solution-phase reactions, rapidly converting a set of representative aliphatic primary and unhindered secondary amines as well as aniline into the corresponding bis(tert-butoxycarbonyl)-protected guanidines. To enable a direct assessment of the reactivity of guanidinylation reagents, conversions were performed in deuterated solvents (d7-DMF or d8-THF), allowing for continuous analysis of the reaction mixtures by 1H and 13C NMR. Likewise, 1H-triazole-1-[N,N'-bis(tert-butoxycarbonyl)]carboxamidine proved to be a versatile reagent in solid-phase conversions, for example, a resin-bound test peptide (KFFKFFK) was fully guanidinylated in only 2 h by using 2 equivalents of the reagent per free amino group. Also, 1H-triazole-1-[N,N'-bis(tert-butoxycarbonyl)]carboxamidine proved capable of completely guanidinylating more sterically hindered N-terminal residues (e.g., N-methyl amino acids or a peptoid) in resin-bound peptides. Its superior reactivity and stability demonstrated under heating conditions make 1H-triazole-1-[N,N'-bis(tert-butoxycarbonyl)]carboxamidine a valuable guanidinylation reagent both in solution- and solid-phase synthesis.
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Affiliation(s)
- Anita Wester
- Center for Peptide-Based Antibiotics, Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Jagtvej 162, DK-2100 Copenhagen East, Denmark
| | - Fredrik Björkling
- Center for Peptide-Based Antibiotics, Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Jagtvej 162, DK-2100 Copenhagen East, Denmark
| | - Henrik Franzyk
- Center for Peptide-Based Antibiotics, Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Jagtvej 162, DK-2100 Copenhagen East, Denmark
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5
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Paulsen MH, Engqvist M, Ausbacher D, Anderssen T, Langer MK, Haug T, Morello GR, Liikanen LE, Blencke HM, Isaksson J, Juskewitz E, Bayer A, Strøm MB. Amphipathic Barbiturates as Mimics of Antimicrobial Peptides and the Marine Natural Products Eusynstyelamides with Activity against Multi-resistant Clinical Isolates. J Med Chem 2021; 64:11395-11417. [PMID: 34314189 DOI: 10.1021/acs.jmedchem.1c00734] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report a series of synthetic cationic amphipathic barbiturates inspired by the pharmacophore model of small antimicrobial peptides (AMPs) and the marine antimicrobials eusynstyelamides. These N,N'-dialkylated-5,5-disubstituted barbiturates consist of an achiral barbiturate scaffold with two cationic groups and two lipophilic side chains. Minimum inhibitory concentrations of 2-8 μg/mL were achieved against 30 multi-resistant clinical isolates of Gram-positive and Gram-negative bacteria, including isolates with extended spectrum β-lactamase-carbapenemase production. The guanidine barbiturate 7e (3,5-di-Br) demonstrated promising in vivo antibiotic efficacy in mice infected with clinical isolates of Escherichia coli and Klebsiella pneumoniae using a neutropenic peritonitis model. Mode of action studies showed a strong membrane disrupting effect and was supported by nuclear magnetic resonance and molecular dynamics simulations. The results express how the pharmacophore model of small AMPs and the structure of the marine eusynstyelamides can be used to design highly potent lead peptidomimetics against multi-resistant bacteria.
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Affiliation(s)
- Marianne H Paulsen
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, NO-9037 Tromsø, Norway
| | - Magnus Engqvist
- Department of Chemistry, UiT The Arctic University of Norway, NO-9037 Tromsø, Norway
| | - Dominik Ausbacher
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, NO-9037 Tromsø, Norway
| | - Trude Anderssen
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, NO-9037 Tromsø, Norway
| | - Manuel K Langer
- Department of Chemistry, UiT The Arctic University of Norway, NO-9037 Tromsø, Norway
| | - Tor Haug
- The Norwegian College of Fishery Science, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, NO-9037 Tromsø, Norway
| | - Glenn R Morello
- Department of Chemistry, UiT The Arctic University of Norway, NO-9037 Tromsø, Norway.,Department of Science, Valley City State University, Valley City, 58072 North Dakota, United States
| | - Laura E Liikanen
- Department of Chemistry, UiT The Arctic University of Norway, NO-9037 Tromsø, Norway
| | - Hans-Matti Blencke
- The Norwegian College of Fishery Science, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, NO-9037 Tromsø, Norway
| | - Johan Isaksson
- Department of Chemistry, UiT The Arctic University of Norway, NO-9037 Tromsø, Norway
| | - Eric Juskewitz
- Department of Medical Biology, Faculty of Health Sciences, UiT The Arctic University of Norway, NO-9037 Tromsø, Norway
| | - Annette Bayer
- Department of Chemistry, UiT The Arctic University of Norway, NO-9037 Tromsø, Norway
| | - Morten B Strøm
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, NO-9037 Tromsø, Norway
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6
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Hansen IKØ, Lövdahl T, Simonovic D, Hansen KØ, Andersen AJC, Devold H, Richard CSM, Andersen JH, Strøm MB, Haug T. Antimicrobial Activity of Small Synthetic Peptides Based on the Marine Peptide Turgencin A: Prediction of Antimicrobial Peptide Sequences in a Natural Peptide and Strategy for Optimization of Potency. Int J Mol Sci 2020; 21:ijms21155460. [PMID: 32751755 PMCID: PMC7432809 DOI: 10.3390/ijms21155460] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 07/28/2020] [Accepted: 07/29/2020] [Indexed: 02/06/2023] Open
Abstract
Turgencin A, a potent antimicrobial peptide isolated from the Arctic sea squirt Synoicum turgens, consists of 36 amino acid residues and three disulfide bridges, making it challenging to synthesize. The aim of the present study was to develop a truncated peptide with an antimicrobial drug lead potential based on turgencin A. The experiments consisted of: (1) sequence analysis and prediction of antimicrobial potential of truncated 10-mer sequences; (2) synthesis and antimicrobial screening of a lead peptide devoid of the cysteine residues; (3) optimization of in vitro antimicrobial activity of the lead peptide using an amino acid replacement strategy; and (4) screening the synthesized peptides for cytotoxic activities. In silico analysis of turgencin A using various prediction software indicated an internal, cationic 10-mer sequence to be putatively antimicrobial. The synthesized truncated lead peptide displayed weak antimicrobial activity. However, by following a systematic amino acid replacement strategy, a modified peptide was developed that retained the potency of the original peptide. The optimized peptide StAMP-9 displayed bactericidal activity, with minimal inhibitory concentrations of 7.8 µg/mL against Staphylococcus aureus and 3.9 µg/mL against Escherichia coli, and no cytotoxic effects against mammalian cells. Preliminary experiments indicate the bacterial membranes as immediate and primary targets.
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Affiliation(s)
- Ida K. Ø. Hansen
- Norwegian College of Fishery Science, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, 9037 Tromsø, Norway; (A.J.C.A.); (H.D.); (C.S.M.R.)
- Correspondence: (I.K.Ø.H.); (T.H.)
| | - Tomas Lövdahl
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, 9037 Tromsø, Norway; (T.L.); (D.S.); (M.B.S.)
| | - Danijela Simonovic
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, 9037 Tromsø, Norway; (T.L.); (D.S.); (M.B.S.)
| | - Kine Ø. Hansen
- Marbio, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Breivika, N-9037 Tromsø, Norway; (K.Ø.H.); (J.H.A.)
| | - Aaron J. C. Andersen
- Norwegian College of Fishery Science, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, 9037 Tromsø, Norway; (A.J.C.A.); (H.D.); (C.S.M.R.)
| | - Hege Devold
- Norwegian College of Fishery Science, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, 9037 Tromsø, Norway; (A.J.C.A.); (H.D.); (C.S.M.R.)
| | - Céline S. M. Richard
- Norwegian College of Fishery Science, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, 9037 Tromsø, Norway; (A.J.C.A.); (H.D.); (C.S.M.R.)
| | - Jeanette H. Andersen
- Marbio, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Breivika, N-9037 Tromsø, Norway; (K.Ø.H.); (J.H.A.)
| | - Morten B. Strøm
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, 9037 Tromsø, Norway; (T.L.); (D.S.); (M.B.S.)
| | - Tor Haug
- Norwegian College of Fishery Science, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, 9037 Tromsø, Norway; (A.J.C.A.); (H.D.); (C.S.M.R.)
- Correspondence: (I.K.Ø.H.); (T.H.)
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7
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Antimicrobial activity of amphipathic α,α-disubstituted β-amino amide derivatives against ESBL - CARBA producing multi-resistant bacteria; effect of halogenation, lipophilicity and cationic character. Eur J Med Chem 2019; 183:111671. [PMID: 31536892 DOI: 10.1016/j.ejmech.2019.111671] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 08/27/2019] [Accepted: 08/30/2019] [Indexed: 02/06/2023]
Abstract
The rapid emergence and spread of multi-resistant bacteria have created an urgent need for new antimicrobial agents. We report here a series of amphipathic α,α-disubstituted β-amino amide derivatives with activity against 30 multi-resistant clinical isolates of Gram-positive and Gram-negative bacteria, including isolates with extended spectrum β-lactamase - carbapenemase (ESBL-CARBA) production. A variety of halogenated aromatic side-chains were investigated to improve antimicrobial potency and minimize formation of Phase I metabolites. Net positive charge and cationic character of the derivatives had an important effect on toxicity against human cell lines. The most potent and selective derivative was the diguanidine derivative 4e with 3,5-di-brominated benzylic side-chains. Derivative 4e displayed minimum inhibitory concentrations (MIC) of 0.25-8 μg/mL against Gram-positive and Gram-negative reference strains, and 2-32 μg/mL against multi-resistant clinical isolates. Derivative 4e showed also low toxicity against human red blood cells (EC50 > 200 μg/mL), human hepatocyte carcinoma cells (HepG2: EC50 > 64 μg/mL), and human lung fibroblast cells (MRC-5: EC50 > 64 μg/mL). The broad-spectrum antimicrobial activity and low toxicity of diguanylated derivatives such as 4e make them attractive as lead compounds for development of novel antimicrobial drugs.
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8
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Igumnova EM, Mishchenko E, Haug T, Blencke HM, Sollid JUE, Fredheim EGA, Lauksund S, Stensvåg K, Strøm MB. Amphipathic sulfonamidobenzamides mimicking small antimicrobial marine natural products; investigation of antibacterial and anti-biofilm activity against antibiotic resistant clinical isolates. Bioorg Med Chem 2018; 26:4930-4941. [PMID: 30185388 DOI: 10.1016/j.bmc.2018.08.032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 08/22/2018] [Accepted: 08/26/2018] [Indexed: 01/20/2023]
Abstract
There is an urgent need for novel antimicrobial agents to address the threat of bacterial resistance to modern society. We have used a structural motif found in antimicrobial marine hit compounds as a basis for synthesizing a library of antimicrobial sulfonamidobenzamide lead compounds. Potent in vitro antimicrobial activity against clinically relevant bacterial strains was demonstrated for two compounds, G6 and J18, with minimal inhibitory concentrations (MIC) of 4-16 μg/ml against clinical methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecium (VRE). The two compounds G6 and J18, together with several other compounds of this library, also caused ≥90% eradication of pre-established biofilm of methicillin-resistant S. epidermidis (MRSE) at 40 μg/ml. Using a luciferase assay, the mechanism of action of G6 was shown to resemble the biocide chlorhexidine by targeting the bacterial cell membrane.
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Affiliation(s)
- Elizaveta M Igumnova
- Department of Pharmacy, Faculty of Health Sciences, UiT - The Arctic University of Norway, NO-9037 Tromsø, Norway
| | - Ekaterina Mishchenko
- The Norwegian College of Fishery Science, Faculty of Biosciences, Fisheries and Economics, UiT - The Arctic University of Norway, NO-9037 Tromsø, Norway
| | - Tor Haug
- The Norwegian College of Fishery Science, Faculty of Biosciences, Fisheries and Economics, UiT - The Arctic University of Norway, NO-9037 Tromsø, Norway
| | - Hans-Matti Blencke
- The Norwegian College of Fishery Science, Faculty of Biosciences, Fisheries and Economics, UiT - The Arctic University of Norway, NO-9037 Tromsø, Norway
| | - Johanna U Ericson Sollid
- Department of Medical Biology, Faculty of Health Sciences, UiT - The Arctic University of Norway, NO-9037 Tromsø, Norway
| | - Elizabeth G Aarag Fredheim
- Department of Pharmacy, Faculty of Health Sciences, UiT - The Arctic University of Norway, NO-9037 Tromsø, Norway
| | - Silje Lauksund
- Department of Pharmacy, Faculty of Health Sciences, UiT - The Arctic University of Norway, NO-9037 Tromsø, Norway
| | - Klara Stensvåg
- The Norwegian College of Fishery Science, Faculty of Biosciences, Fisheries and Economics, UiT - The Arctic University of Norway, NO-9037 Tromsø, Norway
| | - Morten B Strøm
- Department of Pharmacy, Faculty of Health Sciences, UiT - The Arctic University of Norway, NO-9037 Tromsø, Norway.
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9
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Paulsen MH, Karlsen EA, Ausbacher D, Anderssen T, Bayer A, Ochtrop P, Hedberg C, Haug T, Ericson Sollid JU, Strøm MB. An amphipathic cyclic tetrapeptide scaffold containing halogenated β2,2-amino acids with activity against multiresistant bacteria. J Pept Sci 2018; 24:e3117. [DOI: 10.1002/psc.3117] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 06/26/2018] [Accepted: 07/07/2018] [Indexed: 01/28/2023]
Affiliation(s)
- Marianne H. Paulsen
- Department of Pharmacy, Faculty of Health Sciences; UiT-The Arctic University of Norway; Tromsø Norway
| | - Eskil André Karlsen
- Department of Pharmacy, Faculty of Health Sciences; UiT-The Arctic University of Norway; Tromsø Norway
| | | | - Trude Anderssen
- Department of Pharmacy, Faculty of Health Sciences; UiT-The Arctic University of Norway; Tromsø Norway
| | - Annette Bayer
- Department of Chemistry; UiT-The Arctic University of Norway; Tromsø Norway
| | | | | | - Tor Haug
- Norwegian College of Fishery Science, Faculty of Biosciences, Fisheries and Economics; UiT-The Arctic University of Norway; Tromsø Norway
| | - Johanna U. Ericson Sollid
- Department of Medical Biology, Faculty of Health Sciences; UiT-The Arctic University of Norway; Tromsø Norway
| | - Morten B. Strøm
- Department of Pharmacy, Faculty of Health Sciences; UiT-The Arctic University of Norway; Tromsø Norway
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10
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Wagner A, Norris S, Chatterjee P, Morris PF, Wildschutte H. Aquatic Pseudomonads Inhibit Oomycete Plant Pathogens of Glycine max. Front Microbiol 2018; 9:1007. [PMID: 29896163 PMCID: PMC5986895 DOI: 10.3389/fmicb.2018.01007] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 04/30/2018] [Indexed: 11/17/2022] Open
Abstract
Seedling root rot of soybeans caused by the host-specific pathogen Phytophthora sojae, and a large number of Pythium species, is an economically important disease across the Midwest United States that negatively impacts soybean yields. Research on biocontrol strategies for crop pathogens has focused on compounds produced by microbes from soil, however, recent studies suggest that aquatic bacteria express distinct compounds that efficiently inhibit a wide range of pathogens. Based on these observations, we hypothesized that freshwater strains of pseudomonads might be producing novel antagonistic compounds that inhibit the growth of oomycetes. To test this prediction, we utilized a collection of 330 Pseudomonas strains isolated from soil and freshwater habitats, and determined their activity against a panel of five oomycetes: Phytophthora sojae, Pythium heterothalicum, Pythium irregulare, Pythium sylvaticum, and Pythium ultimum, all of which are pathogenic on soybeans. Among the bacterial strains, 118 exhibited antagonistic activity against at least one oomycete species, and 16 strains were inhibitory to all pathogens. Antagonistic activity toward oomycetes was significantly more common for aquatic isolates than for soil isolates. One water-derived strain, 06C 126, was predicted to express a siderophore and exhibited diverse antagonistic profiles when tested on nutrient rich and iron depleted media suggesting that more than one compound was produced that effectively inhibited oomycetes. These results support the concept that aquatic strains are an efficient source of compounds that inhibit pathogens. We outline a strategy to identify other strains that express unique compounds that may be useful biocontrol agents.
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Affiliation(s)
| | | | | | - Paul F. Morris
- Department of Biological Sciences, Bowling Green State University, Bowling Green, OH, United States
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11
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Bakka TA, Strøm MB, Andersen JH, Gautun OR. Methyl propiolate and 3-butynone: Starting points for synthesis of amphiphilic 1,2,3-triazole peptidomimetics for antimicrobial evaluation. Bioorg Med Chem 2017; 25:5380-5395. [PMID: 28797773 DOI: 10.1016/j.bmc.2017.07.060] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 07/28/2017] [Indexed: 11/16/2022]
Abstract
A library of 29 small 1,4-substituted 1,2,3-triazoles was prepared for studies of antimicrobial activity. The pharmacophore model investigated with these substrates was based on small peptidomimetics of antimicrobial peptides and antimicrobials isolated from marine organisms from sub-arctic regions. Using methyl 1,2,3-triazole-carboxylates and 1,2,3-triazole methyl ketones prepared through "click" chemistry we were able to synthesize the different cationic amphiphiles through three steps or less. Several structural modifications to the lipopohilic side and hydrophilic sides of the amphiphiles were investigated and compared with regards to antimicrobial activity and cytotoxicity in particular. The most promising amphiphile 10f displayed minimum inhibitory concentrations (MICs) between 4-16µg/mL against Gram-positive Enterococcus faecalis, Staphylococcus aureus, Streptococcus agalacticae, and Gram-negative Escherichia coli and Pseudomonas aeruginosa. The decent level of antimicrobial activity and biofilm inhibition, short synthesis, and accessible reagents, makes this type of amphiphilic mimics interesting leads for further development.
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Affiliation(s)
- Thomas A Bakka
- Department of Chemistry, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim, Norway
| | - Morten B Strøm
- Department of Pharmacy, Faculty of Health Sciences, UiT - The Arctic University of Norway, NO-9037 Tromsø, Norway
| | - Jeanette H Andersen
- Marbio, Faculty of Biosciences, Fisheries and Economics, UiT - The Arctic University of Norway, NO-9037 Tromsø, Norway
| | - Odd R Gautun
- Department of Chemistry, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim, Norway.
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12
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Michael P, Hansen KØ, Isaksson J, Andersen JH, Hansen E. A Novel Brominated Alkaloid Securidine A, Isolated from the Marine Bryozoan Securiflustra securifrons. Molecules 2017; 22:molecules22071236. [PMID: 28737700 PMCID: PMC6152195 DOI: 10.3390/molecules22071236] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 07/12/2017] [Accepted: 07/17/2017] [Indexed: 02/02/2023] Open
Abstract
A novel brominated alkaloid, Securidine A, was isolated from the cold water marine bryozoan Securiflustra securifrons. Securidine A was isolated using semi-preparative HPLC, and the structure was elucidated by spectroscopic methods. The isolated Securidine A was tested for cytotoxic, antibacterial, and anti-diabetic activities as well as for its potential for inhibition of biofilm formation. No significant biological activity was observed in the applied bioassays, thus expanded bioactivity profiling is required, in order to reveal any potential applications for Securidine A.
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Affiliation(s)
- Priyanka Michael
- MARBIO, UiT-The Arctic University of Norway, Breivika, Tromsø N-9037, Norway.
| | - Kine Ø Hansen
- MARBIO, UiT-The Arctic University of Norway, Breivika, Tromsø N-9037, Norway.
| | - Johan Isaksson
- Department of Chemistry, UiT-The Arctic University of Norway, Breivika, Tromsø N-9037, Norway.
| | - Jeanette H Andersen
- MARBIO, UiT-The Arctic University of Norway, Breivika, Tromsø N-9037, Norway.
| | - Espen Hansen
- MARBIO, UiT-The Arctic University of Norway, Breivika, Tromsø N-9037, Norway.
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Bakka TA, Strøm MB, Andersen JH, Gautun OR. Synthesis and antimicrobial evaluation of cationic low molecular weight amphipathic 1,2,3-triazoles. Bioorg Med Chem Lett 2017; 27:1119-1123. [DOI: 10.1016/j.bmcl.2017.01.092] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 01/28/2017] [Indexed: 11/24/2022]
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