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Gray MJ. The role of metals in hypothiocyanite resistance in Escherichia coli. J Bacteriol 2024; 206:e0009824. [PMID: 39016617 PMCID: PMC11340325 DOI: 10.1128/jb.00098-24] [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: 03/06/2024] [Accepted: 06/25/2024] [Indexed: 07/18/2024] Open
Abstract
The innate immune system employs a variety of antimicrobial oxidants to control and kill host-associated bacteria. Hypothiocyanite/hypothiocyanous acid (-OSCN/HOSCN) is one such antimicrobial oxidant that is synthesized by lactoperoxidase, myeloperoxidase, and eosinophil peroxidase at sites throughout the human body. HOSCN has potent antibacterial activity while being largely non-toxic toward human cells. The molecular mechanisms by which bacteria sense and defend themselves against HOSCN have only recently begun to be elaborated, notably by the discovery of bacterial HOSCN reductase (RclA), an HOSCN-degrading enzyme widely conserved among bacteria that live on epithelial surfaces. In this paper, I show that Ni2+ sensitizes Escherichia coli to HOSCN by inhibiting glutathione reductase and that inorganic polyphosphate protects E. coli against this effect, probably by chelating Ni2+ ions. I also found that RclA is very sensitive to inhibition by Cu2+ and Zn2+, metals that are accumulated to high levels by innate immune cells, and that, surprisingly, thioredoxin and thioredoxin reductase are not involved in HOSCN stress resistance in E. coli. These results advance our understanding of the contribution of different oxidative stress responses and redox buffering pathways to HOSCN resistance in E. coli and illustrate important interactions between metal ions and the enzymes bacteria use to defend themselves against oxidative stress. IMPORTANCE Hypothiocyanite (HOSCN) is an antimicrobial oxidant produced by the innate immune system. The molecular mechanisms by which host-associated bacteria defend themselves against HOSCN have only recently begun to be understood. The results in this paper are significant because they show that the low molecular weight thiol glutathione and enzyme glutathione reductase are critical components of the Escherichia coli HOSCN response, working by a mechanism distinct from that of the HOSCN-specific defenses provided by the RclA, RclB, and RclC proteins and that metal ions (including nickel, copper, and zinc) may impact the ability of bacteria to resist HOSCN by inhibiting specific defensive enzymes (e.g., glutathione reductase or RclA).
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Affiliation(s)
- Michael J. Gray
- Department of Microbiology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
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Gao Y, Guo L, Liu X, Chen N, Yang X, Zhang Q. Advances in the synthesis and applications of macrocyclic polyamines. ROYAL SOCIETY OPEN SCIENCE 2024; 11:231979. [PMID: 39092147 PMCID: PMC11293801 DOI: 10.1098/rsos.231979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 03/03/2024] [Accepted: 04/10/2024] [Indexed: 08/04/2024]
Abstract
Macrocyclic polyamines constitute a significant class of macrocyclic compounds that play a pivotal role in the realm of supramolecular chemistry. They find extensive applications across diverse domains including industrial and agricultural production, clinical diagnostics, environmental protection and other multidisciplinary fields. Macrocyclic polyamines possess a distinctive cavity structure with varying sizes, depths, electron-richness degrees and flexibilities. This unique feature enables them to form specific supramolecular structures through complexation with diverse objects, thereby attracting considerable attention from chemists, biologists and materials scientists alike. However, there is currently a lack of comprehensive summaries on the synthesis methods for macrocyclic polyamines. In this review article, we provide an in-depth introduction to the synthesis of macrocyclic polyamines while analysing their respective advantages and disadvantages. Furthermore, we also present an overview of the recent 5-year advancements in using macrocyclic polyamines as non-viral gene vectors, fluorescent probes, diagnostic and therapeutic reagents as well as catalysts. Looking ahead to future research directions on the synthesis and application of macrocyclic polyamines across various fields will hopefully inspire new ideas for their synthesis and use.
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Affiliation(s)
- Yongguang Gao
- Department of Chemistry, Tangshan Normal University, Tangshan063000, People’s Republic of China
- Hebei Key Laboratory of Degradable Polymers, Tangshan Normal University, Tangshan063000, People’s Republic of China
- Tangshan Silicone Key Laboratory, Tangshan Normal University, Tangshan063000, People’s Republic of China
| | - Lina Guo
- Tangshan First Vocational Secondary Specialized School, Tangshan 063000, People’s Republic of China
| | - Xinhua Liu
- Department of Chemistry, Tangshan Normal University, Tangshan063000, People’s Republic of China
- Hebei Key Laboratory of Degradable Polymers, Tangshan Normal University, Tangshan063000, People’s Republic of China
- Tangshan Silicone Key Laboratory, Tangshan Normal University, Tangshan063000, People’s Republic of China
| | - Na Chen
- Department of Chemistry, Tangshan Normal University, Tangshan063000, People’s Republic of China
- Hebei Key Laboratory of Degradable Polymers, Tangshan Normal University, Tangshan063000, People’s Republic of China
- Tangshan Silicone Key Laboratory, Tangshan Normal University, Tangshan063000, People’s Republic of China
| | - Xiaochun Yang
- Department of Chemistry, Tangshan Normal University, Tangshan063000, People’s Republic of China
- Hebei Key Laboratory of Degradable Polymers, Tangshan Normal University, Tangshan063000, People’s Republic of China
- Tangshan Silicone Key Laboratory, Tangshan Normal University, Tangshan063000, People’s Republic of China
| | - Qing Zhang
- Department of Chemistry, Tangshan Normal University, Tangshan063000, People’s Republic of China
- Hebei Key Laboratory of Degradable Polymers, Tangshan Normal University, Tangshan063000, People’s Republic of China
- Tangshan Silicone Key Laboratory, Tangshan Normal University, Tangshan063000, People’s Republic of China
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Gray MJ. The role of metals in hypothiocyanite resistance in Escherichia coli. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.07.583962. [PMID: 38496647 PMCID: PMC10942458 DOI: 10.1101/2024.03.07.583962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
The innate immune system employs a variety of antimicrobial oxidants to control and kill host-associated bacteria. Hypothiocyanite/hypothiocyanous acid (-OSCN/HOSCN) is one such antimicrobial oxidant that is synthesized by lactoperoxidase, myeloperoxidase, and eosinophil peroxidase at sites throughout the human body. HOSCN has potent antibacterial activity while being largely non-toxic towards human cells. The molecular mechanisms by which bacteria sense and defend themselves against HOSCN have only recently begun to be elaborated, notably by the discovery of bacterial HOSCN reductase (RclA), an HOSCN-degrading enzyme widely conserved among bacteria that live on epithelial surfaces. In this paper, I show that Ni2+ sensitizes Escherichia coli to HOSCN by inhibiting glutathione reductase, and that inorganic polyphosphate protects E. coli against this effect, probably by chelating Ni2+ ions. I also found that RclA is very sensitive to inhibition by Cu2+ and Zn2+, metals that are accumulated to high levels by innate immune cells, and that, surprisingly, thioredoxin and thioredoxin reductase are not involved in HOSCN stress resistance in E. coli. These results advance our understanding of the contribution of different oxidative stress response and redox buffering pathways to HOSCN resistance in E. coli and illustrate important interactions between metal ions and the enzymes bacteria use to defend themselves against oxidative stress.
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Affiliation(s)
- Michael J. Gray
- Department of Microbiology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
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Han X, Mi Y, Ji Y, Sun M, Tang H, Dong F, Guo Z. A novel chitosan antioxidant bearing sulfhydryl group: Synthesis, characterization and activity assessment. Int J Biol Macromol 2024; 261:129816. [PMID: 38290626 DOI: 10.1016/j.ijbiomac.2024.129816] [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: 10/15/2023] [Revised: 01/04/2024] [Accepted: 01/26/2024] [Indexed: 02/01/2024]
Abstract
To improve the antioxidant activity, sulfhydryl groups (-SH) were introduced into chitosan. Acylated chitosan derivatives, chitosan cationic salt derivatives, hydroxypropyl trimethylammonium chloride chitosan quaternary ammonium salt (HACC) derivatives and N,N,N-trimethyl chitosan iodine (TMC) derivatives were obtained. The chitosan derivatives were characterized by FTIR and 1H NMR to confirm the successful synthesis. Ellman's reagent was used to determine that the compound contained free sulfhydryl groups. The water solubility and thermal stability of chitosan and derivatives were evaluated. The antioxidant activities of the derivatives were verified, including DPPH radical scavenging activity, superoxide anion radical scavenging activity and reducing power activity. The novel chitosan derivatives showed excellent antioxidant activities. Toxicity assay used L929 cells proved that the derivatives had no significant toxic. The results showed that the chitosan derivatives bearing sulfhydryl groups described in this paper has a certain antioxidant effect, which provides a practical approach for further study of chitosan.
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Affiliation(s)
- Xiangru Han
- Key Laboratory of Coastal Biology and Bioresource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yingqi Mi
- Key Laboratory of Coastal Biology and Bioresource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuting Ji
- Key Laboratory of Coastal Biology and Bioresource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Mingzhi Sun
- Yantai Fuhui Agricultural Technology Co., Ltd, Yantai 264100, China
| | - Hongxia Tang
- Yantai Fuhui Agricultural Technology Co., Ltd, Yantai 264100, China
| | - Fang Dong
- Key Laboratory of Coastal Biology and Bioresource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhanyong Guo
- Key Laboratory of Coastal Biology and Bioresource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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