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Lee YM, Choi KM, Mun SH, Yoo JW, Jung JH. Gut microbiota composition of the isopod Ligia in South Korea exposed to expanded polystyrene pollution. PLoS One 2024; 19:e0308246. [PMID: 39110709 PMCID: PMC11305568 DOI: 10.1371/journal.pone.0308246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2024] [Accepted: 07/20/2024] [Indexed: 08/10/2024] Open
Abstract
Plastics pose a considerable challenge to aquatic ecosystems because of their increasing global usage and non-biodegradable properties. Coastal plastic debris can persist in ecosystems; however, its effects on resident organisms remain unclear. A metagenomic analysis of the isopoda Ligia, collected from clean (Nae-do, ND) and plastic-contaminated sites (Maemul-do, MD) in South Korea, was conducted to clarify the effects of microplastic contamination on the gut microbiota. Ligia gut microbiota's total operational taxonomic units were higher in ND than in MD. Alpha diversity did not differ significantly between the two Ligia gut microbial communities collected from ND and MD, although richness (Observed species) was lower in MD than in ND. Proteobacteria (67.47%, ND; 57.30%, MD) and Bacteroidetes (13.63%, ND; 20.76%, MD) were the most abundant phyla found at both sites. Significant different genera in Ligia from EPS-polluted sites were observed. Functional gene analysis revealed that 19 plastic degradation-related genes, including those encoding hydrogenase, esterase, and carboxylesterase, were present in the gut microbes of Ligia from MD, indicating the potential role of the Ligia gut microbiota in plastic degradation. This study provides the first comparative field evidence of the gut microbiota dynamics of plastic detritus consumers in marine ecosystems.
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Affiliation(s)
- Young-Mi Lee
- Department of Biotechnology, College of Convergence Engineering, Sangmyung University, Seoul, Republic of Korea
| | - Kwang-Min Choi
- Risk Assessment Research Center, Korea Institute of Ocean Science and Technology, Geoje, Republic of Korea
| | - Seong Hee Mun
- Risk Assessment Research Center, Korea Institute of Ocean Science and Technology, Geoje, Republic of Korea
| | - Je-Won Yoo
- Department of Biotechnology, College of Convergence Engineering, Sangmyung University, Seoul, Republic of Korea
| | - Jee-Hyun Jung
- Risk Assessment Research Center, Korea Institute of Ocean Science and Technology, Geoje, Republic of Korea
- Department of Marine Environmental Science, Korea University of Science and Technology, Daejeon, Republic of Korea
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2
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Luo Z, Li P, Zhang D, Zhu J, Wang W, Zhao W, Li P, Yuan G. A Novel Antimicrobial Mechanism of Azalomycin F Acting on Lipoteichoic Acid Synthase and Cell Envelope. Molecules 2024; 29:856. [PMID: 38398608 PMCID: PMC10893547 DOI: 10.3390/molecules29040856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2023] [Revised: 02/07/2024] [Accepted: 02/09/2024] [Indexed: 02/25/2024] Open
Abstract
Lipoteichoic acid (LTA) plays an essential role in bacterial growth and resistance to antibiotics, and LTA synthetase (LtaS) was considered as an attractive target for combating Gram-positive infections. Azalomycin F, a natural guanidyl-containing polyhydroxy macrolide, can target the LTA of Staphylococcus aureus. Using various technologies including enzyme-linked immunosorbent assay, transmission electron microscope, proteomics, and parallel reaction monitoring, here, the experimental results indicated that azalomycin F can accelerate the LTA release and disrupt the cell envelope, which would also lead to the feedback upregulation on the expressions of LtaS and other related enzymes. Simultaneously, the reconstituted enzyme activity evaluations showed that azalomycin F can significantly inhibit the extracellular catalytic domain of LtaS (eLtaS), while this was vague for LtaS embedded in the liposomes. Subsequently, the fluorescence analyses for five incubation systems containing azalomycin F and eLtaS or the LtaS-embedded liposome indicated that azalomcyin F can spontaneously bind to the active center of LtaS. Combining the mass spectroscopy analyses and the molecular dockings, the results further indicated that this interaction involves the binding sites of substrates and the LTA prolongation, especially the residues Lys299, Phe353, Trp354 and His416. All these suggested that azalomycin F has multiple antibacterial mechanisms against S. aureus. It can not only inhibit LTA biosynthesis through the interactions of its guanidyl side chain with the active center of LtaS but also disrupt the cell envelope through the synergistic effect of accelerating the LTA release, damaging the cell membrane, and electrostatically interacting with LTA. Simultaneously, these antibacterial mechanisms exhibit a synergistic inhibition effect on S. aureus cells, which would eventually cause the cellular autolysis.
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Affiliation(s)
- Zilong Luo
- Biotechnological Engineering Center for Pharmaceutical Research and Development, Jiangxi Agricultural University, Nanchang 330045, China
| | - Pingyi Li
- Biotechnological Engineering Center for Pharmaceutical Research and Development, Jiangxi Agricultural University, Nanchang 330045, China
| | - Duoduo Zhang
- Biotechnological Engineering Center for Pharmaceutical Research and Development, Jiangxi Agricultural University, Nanchang 330045, China
| | - Jianping Zhu
- Laboratory of Natural Medicine and Microbiological Drug, College of Bioscience and Bioengineering, Jiangxi Agricultural University, Nanchang 330045, China
| | - Wan Wang
- School of Basic Medicine, Nanchang Medical College, Nanchang 330006, China
| | - Wenjia Zhao
- Biotechnological Engineering Center for Pharmaceutical Research and Development, Jiangxi Agricultural University, Nanchang 330045, China
| | - Peibo Li
- School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Ganjun Yuan
- Biotechnological Engineering Center for Pharmaceutical Research and Development, Jiangxi Agricultural University, Nanchang 330045, China
- Laboratory of Natural Medicine and Microbiological Drug, College of Bioscience and Bioengineering, Jiangxi Agricultural University, Nanchang 330045, China
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3
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She P, Yang Y, Li L, Li Y, Liu S, Li Z, Zhou L, Wu Y. Repurposing of the antimalarial agent tafenoquine to combat MRSA. mSystems 2023; 8:e0102623. [PMID: 38047647 PMCID: PMC10734505 DOI: 10.1128/msystems.01026-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 10/25/2023] [Indexed: 12/05/2023] Open
Abstract
IMPORTANCE This study represents the first investigation into the antimicrobial effect of TAF against S. aureus and its potential mechanisms. Our data highlighted the effects of TAF against MRSA planktonic cells, biofilms, and persister cells, which is conducive to broadening the application of TAF. Through mechanistic studies, we revealed that TAF targets bacterial cell membranes. In addition, the in vivo experiments in mice demonstrated the safety and antimicrobial efficacy of TAF, suggesting that TAF could be a potential antibacterial drug candidate for the treatment of infections caused by multiple drug-resistant S. aureus.
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Affiliation(s)
- Pengfei She
- Department of Laboratory Medicine, The Third Xiangya Hospital of Central South University, Changsha, China
| | - Yifan Yang
- Department of Laboratory Medicine, The Third Xiangya Hospital of Central South University, Changsha, China
| | - Linhui Li
- Department of Laboratory Medicine, The Third Xiangya Hospital of Central South University, Changsha, China
| | - Yimin Li
- Department of Laboratory Medicine, The Third Xiangya Hospital of Central South University, Changsha, China
| | - Shasha Liu
- Department of Laboratory Medicine, The Third Xiangya Hospital of Central South University, Changsha, China
| | - Zehao Li
- Department of Laboratory Medicine, The Third Xiangya Hospital of Central South University, Changsha, China
| | - Linying Zhou
- Department of Laboratory Medicine, The Affiliated Changsha Hospital of Xiangya School of Medicine (The First Hospital of Changsha), Central South University, Changsha, China
| | - Yong Wu
- Department of Laboratory Medicine, The Affiliated Changsha Hospital of Xiangya School of Medicine (The First Hospital of Changsha), Central South University, Changsha, China
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4
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Douglas EA, Marshall B, Alghamadi A, Joseph EA, Duggan S, Vittorio S, De Luca L, Serpi M, Laabei M. Improved Antibacterial Activity of 1,3,4-Oxadiazole-Based Compounds That Restrict Staphylococcus aureus Growth Independent of LtaS Function. ACS Infect Dis 2023; 9:2141-2159. [PMID: 37828912 PMCID: PMC10644342 DOI: 10.1021/acsinfecdis.3c00250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Indexed: 10/14/2023]
Abstract
The lipoteichoic acid (LTA) biosynthesis pathway has emerged as a promising antimicrobial therapeutic target. Previous studies identified the 1,3,4 oxadiazole compound 1771 as an LTA inhibitor with activity against Gram-positive pathogens. We have succeeded in making six 1771 derivatives and, through subsequent hit validation, identified the incorporation of a pentafluorosulfanyl substituent as central in enhancing activity. Our newly described derivative, compound 13, showed a 16- to 32-fold increase in activity compared to 1771 when tested against a cohort of multidrug-resistant Staphylococcus aureus strains while simultaneously exhibiting an improved toxicity profile against mammalian cells. Molecular techniques were employed in which the assumed target, lipoteichoic acid synthase (LtaS), was both deleted and overexpressed. Neither deletion nor overexpression of LtaS altered 1771 or compound 13 susceptibility; however, overexpression of LtaS increased the MIC of Congo red, a previously identified LtaS inhibitor. These data were further supported by comparing the docking poses of 1771 and derivatives in the LtaS active site, which indicated the possibility of an additional target(s). Finally, we show that both 1771 and compound 13 have activity that is independent of LtaS, extending to cover Gram-negative species if the outer membrane is first permeabilized, challenging the classification that these compounds are strict LtaS inhibitors.
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Affiliation(s)
| | - Brandon Marshall
- School
of Chemistry, Cardiff University, Cardiff CF10 3AT, Wales, U.K.
| | - Arwa Alghamadi
- School
of Chemistry, Cardiff University, Cardiff CF10 3AT, Wales, U.K.
| | - Erin A. Joseph
- School
of Chemistry, Cardiff University, Cardiff CF10 3AT, Wales, U.K.
| | - Seána Duggan
- Medical
Research Council Centre for Medical Mycology at the University of
Exeter, University of Exeter, Exeter EX4 4DQ, U.K.
| | - Serena Vittorio
- Department
of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Messina I-98125, Italy
| | - Laura De Luca
- Department
of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Messina I-98125, Italy
| | - Michaela Serpi
- School
of Chemistry, Cardiff University, Cardiff CF10 3AT, Wales, U.K.
| | - Maisem Laabei
- Department
of Life Sciences, University of Bath, Bath BA2 7AY, U.K.
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5
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He B, Sachla AJ, Helmann JD. TerC proteins function during protein secretion to metalate exoenzymes. Nat Commun 2023; 14:6186. [PMID: 37794032 PMCID: PMC10550928 DOI: 10.1038/s41467-023-41896-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 09/14/2023] [Indexed: 10/06/2023] Open
Abstract
Cytosolic metalloenzymes acquire metals from buffered intracellular pools. How exported metalloenzymes are appropriately metalated is less clear. We provide evidence that TerC family proteins function in metalation of enzymes during export through the general secretion (Sec-dependent) pathway. Bacillus subtilis strains lacking MeeF(YceF) and MeeY(YkoY) have a reduced capacity for protein export and a greatly reduced level of manganese (Mn) in the secreted proteome. MeeF and MeeY copurify with proteins of the general secretory pathway, and in their absence the FtsH membrane protease is essential for viability. MeeF and MeeY are also required for efficient function of the Mn2+-dependent lipoteichoic acid synthase (LtaS), a membrane-localized enzyme with an extracytoplasmic active site. Thus, MeeF and MeeY, representative of the widely conserved TerC family of membrane transporters, function in the co-translocational metalation of Mn2+-dependent membrane and extracellular enzymes.
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Affiliation(s)
- Bixi He
- Department of Microbiology, Cornell University, 370 Wing Hall, 123 Wing Drive, Ithaca, NY, 14853-8101, USA
| | - Ankita J Sachla
- Department of Microbiology, Cornell University, 370 Wing Hall, 123 Wing Drive, Ithaca, NY, 14853-8101, USA
| | - John D Helmann
- Department of Microbiology, Cornell University, 370 Wing Hall, 123 Wing Drive, Ithaca, NY, 14853-8101, USA.
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6
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Jeong GJ, Khan F, Tabassum N, Cho KJ, Kim YM. Controlling biofilm and virulence properties of Gram-positive bacteria by targeting wall teichoic acid and lipoteichoic acid. Int J Antimicrob Agents 2023; 62:106941. [PMID: 37536571 DOI: 10.1016/j.ijantimicag.2023.106941] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 07/19/2023] [Accepted: 07/27/2023] [Indexed: 08/05/2023]
Abstract
Wall teichoic acid (WTA) and lipoteichoic acid (LTA) are structural components of Gram-positive bacteria's peptidoglycan and cell membrane, which are mostly anionic glycopolymers. WTA confers numerous physiological, virulence, and pathogenic features to bacterial pathogens. It controls cell shape, cell division, and the localisation of autolytic enzymes and ion homeostasis. In the context of virulence and pathogenicity, it aids bacterial cell attachment and colonisation and protects against the host defence system and antibiotics. Having such a broad function in pathogenic bacteria's lifecycle, WTA/LTA become one of the potential targets for antibacterial agents to reduce bacterial infection in the host. The number of reports for targeting the WTA/LTA pathway has risen, mostly by focusing on three distinct targets: antivirulence targets, β-lactam potentiator targets, and essential targets. The current review looked at the role of WTA/LTA in biofilm development and virulence in a range of Gram-positive pathogenic bacteria. Furthermore, alternate strategies, such as the application of natural and synthetic compounds that target the WTA/LTA pathway, have been thoroughly discussed. Moreover, the application of nanomaterials and a combination of drugs have also been discussed as a viable method for targeting the WTA/LTA in numerous Gram-positive bacteria. In addition, a future perspective for controlling bacterial infection by targeting the WTA/LTA is proposed.
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Affiliation(s)
- Geum-Jae Jeong
- Department of Food Science and Technology, Pukyong National University, Busan, Republic of Korea
| | - Fazlurrahman Khan
- Marine Integrated Biomedical Technology Center, The National Key Research Institutes in Universities, Pukyong National University, Busan, 48513, Republic of Korea; Research Center for Marine Integrated Bionics Technology, Pukyong National University, Busan 48513, Republic of Korea.
| | - Nazia Tabassum
- Marine Integrated Biomedical Technology Center, The National Key Research Institutes in Universities, Pukyong National University, Busan, 48513, Republic of Korea; Research Center for Marine Integrated Bionics Technology, Pukyong National University, Busan 48513, Republic of Korea
| | - Kyung-Jin Cho
- Department of Food Science and Technology, Pukyong National University, Busan, Republic of Korea
| | - Young-Mog Kim
- Department of Food Science and Technology, Pukyong National University, Busan, Republic of Korea; Marine Integrated Biomedical Technology Center, The National Key Research Institutes in Universities, Pukyong National University, Busan, 48513, Republic of Korea; Research Center for Marine Integrated Bionics Technology, Pukyong National University, Busan 48513, Republic of Korea.
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7
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Douglas EJA, Wulandari SW, Lovell SD, Laabei M. Novel antimicrobial strategies to treat multi-drug resistant Staphylococcus aureus infections. Microb Biotechnol 2023; 16:1456-1474. [PMID: 37178319 PMCID: PMC10281381 DOI: 10.1111/1751-7915.14268] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 04/12/2023] [Accepted: 04/18/2023] [Indexed: 05/15/2023] Open
Abstract
Antimicrobial resistance is a major obstacle for the treatment of infectious diseases and currently represents one of the most significant threats to global health. Staphylococcus aureus remains a formidable human pathogen with high mortality rates associated with severe systemic infections. S. aureus has become notorious as a multidrug resistant bacterium, which when combined with its extensive arsenal of virulence factors that exacerbate disease, culminates in an incredibly challenging pathogen to treat clinically. Compounding this major health issue is the lack of antibiotic discovery and development, with only two new classes of antibiotics approved for clinical use in the last 20 years. Combined efforts from the scientific community have reacted to the threat of dwindling treatment options to combat S. aureus disease in several innovative and exciting developments. This review describes current and future antimicrobial strategies aimed at treating staphylococcal colonization and/or disease, examining therapies that show significant promise at the preclinical development stage to approaches that are currently being investigated in clinical trials.
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8
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He B, Sachla AJ, Helmann JD. TerC Proteins Function During Protein Secretion to Metalate Exoenzymes. RESEARCH SQUARE 2023:rs.3.rs-2860473. [PMID: 37292672 PMCID: PMC10246235 DOI: 10.21203/rs.3.rs-2860473/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Cytosolic metalloenzymes acquire metals from buffered intracellular pools. How exported metalloenzymes are appropriately metalated is less clear. We provide evidence that TerC family proteins function in metalation of enzymes during export through the general secretion (Sec-dependent) pathway. Bacillus subtilis strains lacking MeeF(YceF) and MeeY(YkoY) have a reduced capacity for protein export and a greatly reduced level of manganese (Mn) in the secreted proteome. MeeF and MeeY copurify with proteins of the general secretory pathway, and in their absence the FtsH membrane protease is essential for viability. MeeF and MeeY are also required for efficient function of the Mn2+-dependent lipoteichoic acid synthase (LtaS), a membrane-localized enzyme with an extracytoplasmic active site. Thus, MeeF and MeeY, representative of the widely conserved TerC family of membrane transporters, function in the co-translocational metalation of Mn2+-dependent membrane and extracellular enzymes.
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Affiliation(s)
- Bixi He
- Department of Microbiology, Cornell University, 370 Wing Hall, 123 Wing Drive, Ithaca, New York 14853-8101, USA
| | - Ankita J. Sachla
- Department of Microbiology, Cornell University, 370 Wing Hall, 123 Wing Drive, Ithaca, New York 14853-8101, USA
| | - John D. Helmann
- Department of Microbiology, Cornell University, 370 Wing Hall, 123 Wing Drive, Ithaca, New York 14853-8101, USA
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9
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Serpi M, Pertusati F, Morozzi C, Novelli G, Giannantonio D, Duggan K, Vittorio S, Fallis IA, De Luca L, Williams D. Synthesis, molecular docking and antibacterial activity of an oxadiazole-based lipoteichoic acid inhibitor and its metabolites. J Mol Struct 2023; 1278:None. [PMID: 38312219 PMCID: PMC10836577 DOI: 10.1016/j.molstruc.2023.134977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 01/12/2023] [Accepted: 01/14/2023] [Indexed: 01/16/2023]
Abstract
Amongst drug resistant Gram-positive bacteria, Staphylococcus aureus is a pathogen of great concern as it is the leading cause of life-threatening nosocomial and community acquired infections which are often associated with implanted medical devices. The biosynthesis of lipotheicoic acid (LTA) by S. aureus has been recognized as a promising antibacterial target, owing its critical role in the growth and survival of Gram-positive bacteria. Here we report for the first time the chemical synthesis and characterisation of an oxadiazole based compound (1771), previously described as an inhibitor of LTA biosynthesis by targeting Lta synthase enzyme (LtaS). To investigate its controversial mode of action, we also performed molecular docking studies, which indicated that 1771 behaves as a competitive inhibitor against LtaS. We also synthesised and evaluated the antimicrobial activity of 1771 metabolites which we have identified from its decomposition in mouse serum, proving that the biological activity was caused by intact 1771.
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Affiliation(s)
- Michaela Serpi
- School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff, Wales CF10 3AT, United Kingdom
| | - Fabrizio Pertusati
- School of Pharmacy and Pharmaceutical Sciences, Redwood Building, King Edwards VII avenue, Cardiff, Wales CF10 3NB, United Kingdom
| | - Chiara Morozzi
- School of Pharmacy and Pharmaceutical Sciences, Redwood Building, King Edwards VII avenue, Cardiff, Wales CF10 3NB, United Kingdom
| | - Giulia Novelli
- School of Pharmacy and Pharmaceutical Sciences, Redwood Building, King Edwards VII avenue, Cardiff, Wales CF10 3NB, United Kingdom
| | - Daniele Giannantonio
- School of Pharmacy and Pharmaceutical Sciences, Redwood Building, King Edwards VII avenue, Cardiff, Wales CF10 3NB, United Kingdom
| | - Katrina Duggan
- Oral and Biomedical Sciences, School of Dentistry, Cardiff University, Cardiff, United Kingdom
| | - Serena Vittorio
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Viale F. Stagno D'Alcontres 31, Messina I-98125, Italy
| | - Ian A. Fallis
- School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff, Wales CF10 3AT, United Kingdom
| | - Laura De Luca
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Viale F. Stagno D'Alcontres 31, Messina I-98125, Italy
| | - David Williams
- Oral and Biomedical Sciences, School of Dentistry, Cardiff University, Cardiff, United Kingdom
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10
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He B, Sachla AJ, Helmann JD. TerC Proteins Function During Protein Secretion to Metalate Exoenzymes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.10.536223. [PMID: 37090602 PMCID: PMC10120614 DOI: 10.1101/2023.04.10.536223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
Cytosolic metalloenzymes acquire metals from buffered intracellular pools. How exported metalloenzymes are appropriately metalated is less clear. We provide evidence that TerC family proteins function in metalation of enzymes during export through the general secretion (Sec-dependent) pathway. Bacillus subtilis strains lacking MeeF(YceF) and MeeY(YkoY) have a reduced capacity for protein export and a greatly reduced level of manganese (Mn) in the secreted proteome. MeeF and MeeY copurify with proteins of the general secretory pathway, and in their absence the FtsH membrane protease is essential for viability. MeeF and MeeY are also required for efficient function of the Mn 2+ -dependent lipoteichoic acid synthase (LtaS), a membrane-localized enzyme with an extracytoplasmic active site. Thus, MeeF and MeeY, representative of the widely conserved TerC family of membrane transporters, function in the co-translocational metalation of Mn 2+ -dependent membrane and extracellular enzymes.
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Affiliation(s)
- Bixi He
- Department of Microbiology, Cornell University, 370 Wing Hall, 123 Wing Drive, Ithaca, New York 14853-8101, USA
| | - Ankita J. Sachla
- Department of Microbiology, Cornell University, 370 Wing Hall, 123 Wing Drive, Ithaca, New York 14853-8101, USA
| | - John D. Helmann
- Department of Microbiology, Cornell University, 370 Wing Hall, 123 Wing Drive, Ithaca, New York 14853-8101, USA
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11
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Dhanda G, Acharya Y, Haldar J. Antibiotic Adjuvants: A Versatile Approach to Combat Antibiotic Resistance. ACS OMEGA 2023; 8:10757-10783. [PMID: 37008128 PMCID: PMC10061514 DOI: 10.1021/acsomega.3c00312] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 02/21/2023] [Indexed: 06/13/2023]
Abstract
The problem of antibiotic resistance is on the rise, with multidrug-resistant strains emerging even to the last resort antibiotics. The drug discovery process is often stalled by stringent cut-offs required for effective drug design. In such a scenario, it is prudent to delve into the varying mechanisms of resistance to existing antibiotics and target them to improve antibiotic efficacy. Nonantibiotic compounds called antibiotic adjuvants which target bacterial resistance can be used in combination with obsolete drugs for an improved therapeutic regime. The field of "antibiotic adjuvants" has gained significant traction in recent years where mechanisms other than β-lactamase inhibition have been explored. This review discusses the multitude of acquired and inherent resistance mechanisms employed by bacteria to resist antibiotic action. The major focus of this review is how to target these resistance mechanisms by the use of antibiotic adjuvants. Different types of direct acting and indirect resistance breakers are discussed including enzyme inhibitors, efflux pump inhibitors, inhibitors of teichoic acid synthesis, and other cellular processes. The multifaceted class of membrane-targeting compounds with poly pharmacological effects and the potential of host immune-modulating compounds have also been reviewed. We conclude with providing insights about the existing challenges preventing clinical translation of different classes of adjuvants, especially membrane-perturbing compounds, and a framework about the possible directions which can be pursued to fill this gap. Antibiotic-adjuvant combinatorial therapy indeed has immense potential to be used as an upcoming orthogonal strategy to conventional antibiotic discovery.
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Affiliation(s)
- Geetika Dhanda
- Antimicrobial
Research Laboratory, New Chemistry Unit and School of Advanced
Materials, Jawaharlal Nehru Centre for Advanced
Scientific Research (JNCASR), Jakkur, Bengaluru 560064, Karnataka, India
| | - Yash Acharya
- Antimicrobial
Research Laboratory, New Chemistry Unit and School of Advanced
Materials, Jawaharlal Nehru Centre for Advanced
Scientific Research (JNCASR), Jakkur, Bengaluru 560064, Karnataka, India
| | - Jayanta Haldar
- Antimicrobial
Research Laboratory, New Chemistry Unit and School of Advanced
Materials, Jawaharlal Nehru Centre for Advanced
Scientific Research (JNCASR), Jakkur, Bengaluru 560064, Karnataka, India
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12
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Abstract
Gram-positive bacterial cells are protected from the environment by a cell envelope that is comprised of a thick layer of peptidoglycan that maintains cell shape and teichoic acid polymers whose biological function remains unclear. In Bacillus subtilis, the loss of all class A penicillin-binding proteins (aPBPs), which function in peptidoglycan synthesis, is conditionally lethal. Here, we show that this lethality is associated with an alteration of lipoteichoic acids (LTAs) and the accumulation of the major autolysin LytE in the cell wall. Our analysis provides further evidence that the length and abundance of LTAs act to regulate the cellular level and activity of autolytic enzymes, specifically LytE. Importantly, we identify a novel function for the aminoacyl-phosphatidylglycerol synthase MprF in the modulation of LTA biosynthesis in both B. subtilis and Staphylococcus aureus. This finding has implications for our understanding of antimicrobial resistance (particularly to daptomycin) in clinically relevant bacteria and the involvement of MprF in the virulence of pathogens such as methicillin-resistant S. aureus (MRSA). IMPORTANCE In Gram-positive bacteria such as Bacillus subtilis and Staphylococcus aureus, the cell envelope is a structure that protects the cells from the environment but is also dynamic in that it must be modified in a controlled way to allow cell growth. In this study, we show that lipoteichoic acids (LTAs), which are anionic polymers attached to the membrane, have a direct role in modulating the cellular abundance of cell wall-degrading enzymes. We also find that the apparent length of the LTA is modulated by the activity of the enzyme MprF, previously implicated in modifications of the cell membrane leading to resistance to antimicrobial peptides. These findings are important contributions to our understanding of how bacteria balance cell wall synthesis and degradation to permit controlled growth and division. These results also have implications for the interpretation of antibiotic resistance, particularly for the clinical treatment of MRSA infections.
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