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Keydel T, Link A. Synthetic Approaches, Properties, and Applications of Acylals in Preparative and Medicinal Chemistry. Molecules 2024; 29:4451. [PMID: 39339447 PMCID: PMC11434492 DOI: 10.3390/molecules29184451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2024] [Revised: 09/16/2024] [Accepted: 09/17/2024] [Indexed: 09/30/2024] Open
Abstract
Diesters of geminal diols (R-CH(O-CO-R')2, RR'C(OCOR″)2, etc. with R = H, aryl or alkyl) are termed acylals according to IUPAC recommendations (Rule P-65.6.3.6 Acylals) if the acids involved are carboxylic acids. Similar condensation products can be obtained from various other acidic structures as well, but these related "non-classical acylals", as one might call them, differ in various aspects from classical acylals and will not be discussed in this article. Carboxylic acid diesters of geminal diols play a prominent role in organic chemistry, not only in their application as protective groups for aldehydes and ketones but also as precursors in the total synthesis of natural compounds and in a variety of organic reactions. What is more, acylals are useful as a key structural motif in clinically validated prodrug approaches. In this review, we summarise the syntheses and chemical properties of such classical acylals and show what potentially under-explored possibilities exist in the field of drug design, especially prodrugs, and classify this functional group in medicinal chemistry.
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Affiliation(s)
| | - Andreas Link
- Institute of Pharmacy, University of Greifswald, 17489 Greifswald, Germany;
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Henriksen NNSE, Lindqvist LL, Wibowo M, Sonnenschein EC, Bentzon-Tilia M, Gram L. Role is in the eye of the beholder-the multiple functions of the antibacterial compound tropodithietic acid produced by marine Rhodobacteraceae. FEMS Microbiol Rev 2022; 46:fuac007. [PMID: 35099011 PMCID: PMC9075582 DOI: 10.1093/femsre/fuac007] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 01/24/2022] [Accepted: 01/27/2022] [Indexed: 11/13/2022] Open
Abstract
Many microbial secondary metabolites have been studied for decades primarily because of their antimicrobial properties. However, several of these metabolites also possess nonantimicrobial functions, both influencing the physiology of the producer and their ecological neighbors. An example of a versatile bacterial secondary metabolite with multiple functions is the tropone derivative tropodithietic acid (TDA). TDA is a broad-spectrum antimicrobial compound produced by several members of the Rhodobacteraceae family, a major marine bacterial lineage, within the genera Phaeobacter, Tritonibacter, and Pseudovibrio. The production of TDA is governed by the mode of growth and influenced by the availability of nutrient sources. The antibacterial effect of TDA is caused by disruption of the proton motive force of target microorganisms and, potentially, by its iron-chelating properties. TDA also acts as a signaling molecule, affecting gene expression in other bacteria, and altering phenotypic traits such as motility, biofilm formation, and antibiotic production in the producer. In microbial communities, TDA-producing bacteria cause a reduction of the relative abundance of closely related species and some fast-growing heterotrophic bacteria. Here, we summarize the current understanding of the chemical ecology of TDA, including the environmental niches of TDA-producing bacteria, and the molecular mechanisms governing the function and regulation of TDA.
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Affiliation(s)
- Nathalie N S E Henriksen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts, Plads Bldg. 221, DK-2800 Kgs. Lyngby, Denmark
| | - Laura L Lindqvist
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts, Plads Bldg. 221, DK-2800 Kgs. Lyngby, Denmark
| | - Mario Wibowo
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts, Plads Bldg. 221, DK-2800 Kgs. Lyngby, Denmark
| | - Eva C Sonnenschein
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts, Plads Bldg. 221, DK-2800 Kgs. Lyngby, Denmark
| | - Mikkel Bentzon-Tilia
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts, Plads Bldg. 221, DK-2800 Kgs. Lyngby, Denmark
| | - Lone Gram
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts, Plads Bldg. 221, DK-2800 Kgs. Lyngby, Denmark
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The Roseobacter-Group Bacterium Phaeobacter as a Safe Probiotic Solution for Aquaculture. Appl Environ Microbiol 2021; 87:e0258120. [PMID: 33310713 DOI: 10.1128/aem.02581-20] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Phaeobacter inhibens has been assessed as a probiotic bacterium for application in aquaculture. Studies addressing the efficacy and safety indicate that P. inhibens maintains its antagonistic activity against pathogenic vibrios in aquaculture live cultures (live feed and fish egg/larvae) while having no or a positive effect on the host organisms and a minor impact on the host microbiomes. While P. inhibens produces antibacterial and algicidal compounds, no study has so far found a virulent phenotype of P. inhibens cells against higher organisms. Additionally, an in silico search for antibiotic resistance genes using published genomes of representative strains did not raise concerns regarding the risk for antimicrobial resistance. P. inhibens occurs naturally in aquaculture systems, supporting its safe usage in this environment. In conclusion, at the current state of knowledge, P. inhibens is a "safe-to-use" organism.
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Duan Y, Petzold M, Saleem‐Batcha R, Teufel R. Bacterial Tropone Natural Products and Derivatives: Overview of their Biosynthesis, Bioactivities, Ecological Role and Biotechnological Potential. Chembiochem 2020; 21:2384-2407. [PMID: 32239689 PMCID: PMC7497051 DOI: 10.1002/cbic.201900786] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 04/02/2020] [Indexed: 12/05/2022]
Abstract
Tropone natural products are non-benzene aromatic compounds of significant ecological and pharmaceutical interest. Herein, we highlight current knowledge on bacterial tropones and their derivatives such as tropolones, tropodithietic acid, and roseobacticides. Their unusual biosynthesis depends on a universal CoA-bound precursor featuring a seven-membered carbon ring as backbone, which is generated by a side reaction of the phenylacetic acid catabolic pathway. Enzymes encoded by separate gene clusters then further modify this key intermediate by oxidation, CoA-release, or incorporation of sulfur among other reactions. Tropones play important roles in the terrestrial and marine environment where they act as antibiotics, algaecides, or quorum sensing signals, while their bacterial producers are often involved in symbiotic interactions with plants and marine invertebrates (e. g., algae, corals, sponges, or mollusks). Because of their potent bioactivities and of slowly developing bacterial resistance, tropones and their derivatives hold great promise for biomedical or biotechnological applications, for instance as antibiotics in (shell)fish aquaculture.
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Affiliation(s)
- Ying Duan
- Faculty of BiologyUniversity of Freiburg79104FreiburgGermany
| | - Melanie Petzold
- Faculty of BiologyUniversity of Freiburg79104FreiburgGermany
| | | | - Robin Teufel
- Faculty of BiologyUniversity of Freiburg79104FreiburgGermany
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Dittmann KK, Porsby CH, Goncalves P, Mateiu RV, Sonnenschein EC, Bentzon-Tilia M, Egan S, Gram L. Tropodithietic acid induces oxidative stress response, cell envelope biogenesis and iron uptake in Vibrio vulnificus. ENVIRONMENTAL MICROBIOLOGY REPORTS 2019; 11:581-588. [PMID: 31102321 DOI: 10.1111/1758-2229.12771] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 05/14/2019] [Accepted: 05/15/2019] [Indexed: 06/09/2023]
Abstract
The Roseobacter group is a widespread marine bacterial group, of which some species produce the broad-spectrum antibiotic tropodithietic acid (TDA). A mode of action for TDA has previously been proposed in Escherichia coli, but little is known about its effect on non-producing marine bacteria at in situ concentrations. The purpose of this study was to investigate how a sub-lethal level of TDA affects Vibrio vulnificus at different time points (30 and 60 min) using a transcriptomic approach. Exposure to TDA for as little as 30 min resulted in the differential expression of genes associated with cell regeneration, including the up-regulation of those involved in biogenesis of the cell envelope. Defence mechanisms including oxidative stress defence proteins and iron uptake systems were also up-regulated in response to TDA, while motility-related genes were down-regulated. Gene expression data and scanning electron microscopy imaging revealed a switch to a biofilm phenotype in the presence of TDA. Our study shows that a low concentration of this antibiotic triggers a defence response to reactive oxygen species and iron depletion in V. vulnificus, which indicates that the mode of action of TDA is likely more complex in this bacterium than what is known for E. coli.
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Affiliation(s)
- Karen K Dittmann
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kgs. Lyngby, DK-2800, Denmark
- School of Biological, Earth and Environmental Sciences, The University of New South Wales, Randwick, NSW, 2052, Australia
| | - Cisse H Porsby
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kgs. Lyngby, DK-2800, Denmark
| | - Priscila Goncalves
- School of Biological, Earth and Environmental Sciences, The University of New South Wales, Randwick, NSW, 2052, Australia
| | - Ramona Valentina Mateiu
- Center for Electron Nanoscopy, Technical University of Denmark, Kgs. Lyngby, DK-2800, Denmark
| | - Eva C Sonnenschein
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kgs. Lyngby, DK-2800, Denmark
| | - Mikkel Bentzon-Tilia
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kgs. Lyngby, DK-2800, Denmark
| | - Suhelen Egan
- School of Biological, Earth and Environmental Sciences, The University of New South Wales, Randwick, NSW, 2052, Australia
| | - Lone Gram
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kgs. Lyngby, DK-2800, Denmark
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Beyersmann PG, Tomasch J, Son K, Stocker R, Göker M, Wagner-Döbler I, Simon M, Brinkhoff T. Dual function of tropodithietic acid as antibiotic and signaling molecule in global gene regulation of the probiotic bacterium Phaeobacter inhibens. Sci Rep 2017; 7:730. [PMID: 28389641 PMCID: PMC5429656 DOI: 10.1038/s41598-017-00784-7] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 03/13/2017] [Indexed: 01/12/2023] Open
Abstract
Antibiotics are typically regarded as microbial weapons, but whereas their function at concentrations lethal for bacteria is often well characterized, the role of antibiotics at much lower concentrations as possibly found under natural conditions remains poorly understood. By using whole-transcriptome analyses and phenotypic screenings of the marine bacterium Phaeobacter inhibens we found that the broad-spectrum antibiotic tropodithietic acid (TDA) causes the same regulatory effects in quorum sensing (QS) as the common signaling molecule N-acyl-homoserine lactone (AHL) at concentrations 100-fold lower than the minimal inhibitory concentration against bacteria. Our results show that TDA has a significant impact on the expression of ~10% of the total genes of P. inhibens, in the same manner as the AHL. Furthermore, TDA needs the AHL associated LuxR-type transcriptional regulator, just as the AHL molecule. Low concentrations of antibiotics can obviously have a strong influence on the global gene expression of the bacterium that produces it and drastically change the metabolism and behaviour of the bacterium. For P. inhibens this includes motility, biofilm formation and antibiotic production, all important for settlement on new host-associated surfaces. Our results demonstrate that bacteria can produce antibiotics not only to antagonise other bacteria, but also to mediate QS like endogenous AHL molecules.
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Affiliation(s)
- Paul G Beyersmann
- Institute for Chemistry and Biology of the Marine Environment (ICBM), University of Oldenburg, 26129, Oldenburg, Germany
| | - Jürgen Tomasch
- Helmholtz Centre for Infection Research, 38124, Braunschweig, Germany
| | - Kwangmin Son
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Roman Stocker
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- Institute for Environmental Engineering, Department of Civil, Environmental and Geomatic Engineering, Eidgenössische Technische Hochschule (ETH) Zürich, Zurich, 8093, Switzerland
| | - Markus Göker
- Leibniz-Institute DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, 38124, Braunschweig, Germany
| | | | - Meinhard Simon
- Institute for Chemistry and Biology of the Marine Environment (ICBM), University of Oldenburg, 26129, Oldenburg, Germany
| | - Thorsten Brinkhoff
- Institute for Chemistry and Biology of the Marine Environment (ICBM), University of Oldenburg, 26129, Oldenburg, Germany.
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Rasmussen BB, Grotkjær T, D'Alvise PW, Yin G, Zhang F, Bunk B, Spröer C, Bentzon-Tilia M, Gram L. Vibrio anguillarum Is Genetically and Phenotypically Unaffected by Long-Term Continuous Exposure to the Antibacterial Compound Tropodithietic Acid. Appl Environ Microbiol 2016; 82:4802-4810. [PMID: 27235441 PMCID: PMC4984299 DOI: 10.1128/aem.01047-16] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 05/24/2016] [Indexed: 01/12/2023] Open
Abstract
UNLABELLED Minimizing the use of antibiotics in the food production chain is essential for limiting the development and spread of antibiotic-resistant bacteria. One alternative intervention strategy is the use of probiotic bacteria, and bacteria of the marine Roseobacter clade are capable of antagonizing fish-pathogenic vibrios in fish larvae and live feed cultures for fish larvae. The antibacterial compound tropodithietic acid (TDA), an antiporter that disrupts the proton motive force, is key in the antibacterial activity of several roseobacters. Introducing probiotics on a larger scale requires understanding of any potential side effects of long-term exposure of the pathogen to the probionts or any compounds they produce. Here we exposed the fish pathogen Vibrio anguillarum to TDA for several hundred generations in an adaptive evolution experiment. No tolerance or resistance arose during the 90 days of exposure, and whole-genome sequencing of TDA-exposed lineages and clones revealed few mutational changes, compared to lineages grown without TDA. Amino acid-changing mutations were found in two to six different genes per clone; however, no mutations appeared unique to the TDA-exposed lineages or clones. None of the virulence genes of V. anguillarum was affected, and infectivity assays using fish cell lines indicated that the TDA-exposed lineages and clones were less invasive than the wild-type strain. Thus, long-term TDA exposure does not appear to result in TDA resistance and the physiology of V. anguillarum appears unaffected, supporting the application of TDA-producing roseobacters as probiotics in aquaculture. IMPORTANCE It is important to limit the use of antibiotics in our food production, to reduce the risk of bacteria developing antibiotic resistance. We showed previously that marine bacteria of the Roseobacter clade can prevent or reduce bacterial diseases in fish larvae, acting as probiotics. Roseobacters produce the antimicrobial compound tropodithietic acid (TDA), and we were concerned regarding whether long-term exposure to this compound could induce resistance or affect the disease-causing ability of the fish pathogen. Therefore, we exposed the fish pathogen Vibrio anguillarum to increasing TDA concentrations over 3 months. We did not see the development of any resistance to TDA, and subsequent infection assays revealed that none of the TDA-exposed clones had increased virulence toward fish cells. Hence, this study supports the use of roseobacters as a non-risk-based disease control measure in aquaculture.
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Affiliation(s)
| | - Torben Grotkjær
- Department of Systems Biology, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Paul W D'Alvise
- Department of Systems Biology, Technical University of Denmark, Kongens Lyngby, Denmark
| | | | - Faxing Zhang
- Beijing Genomics Institute Europe, Copenhagen, Denmark
| | - Boyke Bunk
- Leibniz Institute, DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Cathrin Spröer
- Leibniz Institute, DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Mikkel Bentzon-Tilia
- Department of Systems Biology, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Lone Gram
- Department of Systems Biology, Technical University of Denmark, Kongens Lyngby, Denmark
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Wichmann H, Brinkhoff T, Simon M, Richter-Landsberg C. Dimethylsulfoniopropionate Promotes Process Outgrowth in Neural Cells and Exerts Protective Effects against Tropodithietic Acid. Mar Drugs 2016; 14:md14050089. [PMID: 27164116 PMCID: PMC4882563 DOI: 10.3390/md14050089] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 04/22/2016] [Accepted: 04/27/2016] [Indexed: 01/10/2023] Open
Abstract
The marine environment harbors a plethora of bioactive substances, including drug candidates of potential value in the field of neuroscience. The present study was undertaken to investigate the effects of dimethylsulfoniopropionate (DMSP), produced by several algae, corals and higher plants, on cells of the mammalian nervous system, i.e., neuronal N2a and OLN-93 cells as model system for nerve cells and glia, respectively. Additionally, the protective capabilities of DMSP were assessed in cells treated with tropodithietic acid (TDA), a marine metabolite produced by several Roseobacter clade bacteria. Both cell lines, N2a and OLN-93, have previously been shown to be a sensitive target for the action of TDA, and cytotoxic effects of TDA have been connected to the induction of oxidative stress. Our data shows that DMSP promotes process outgrowth and microtubule reorganization and bundling, accompanied by an increase in alpha-tubulin acetylation. Furthermore, DMSP was able to prevent the cytotoxic effects exerted by TDA, including the breakdown of the mitochondrial membrane potential, upregulation of heat shock protein Hsp32 and activation of the extracellular signal-regulated kinases 1/2 (ERK1/2). Our study points to the conclusion that DMSP provides an antioxidant defense, not only in algae but also in mammalian neural cells.
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Affiliation(s)
- Heidi Wichmann
- Aquatic Microbial Ecology Group, Institute for Chemistry and Biology of the Marine Environment (ICBM), University of Oldenburg, Oldenburg 26129, Germany.
| | - Thorsten Brinkhoff
- Aquatic Microbial Ecology Group, Institute for Chemistry and Biology of the Marine Environment (ICBM), University of Oldenburg, Oldenburg 26129, Germany.
| | - Meinhard Simon
- Aquatic Microbial Ecology Group, Institute for Chemistry and Biology of the Marine Environment (ICBM), University of Oldenburg, Oldenburg 26129, Germany.
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