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Guo F, Quan R, Cui Y, Cao X, Wen T, Xu F. Effects of OxyR regulator on oxidative stress, Apx toxin secretion and virulence of Actinobacillus pleuropneumoniae. Front Cell Infect Microbiol 2024; 13:1324760. [PMID: 38268788 PMCID: PMC10806198 DOI: 10.3389/fcimb.2023.1324760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 12/18/2023] [Indexed: 01/26/2024] Open
Abstract
Introduction Actinobacillus pleuropneumoniae, the causative agent of porcine pleuropneumonia, poses a significant threat to global swine populations due to its high prevalence, mortality rates, and substantial economic ramifications. Understanding the pathogen's defense mechanisms against host-produced reactive oxygen species is crucial for its survival, with OxyR, a conserved bacterial transcription factor, being pivotal in oxidative stress response. Methods This study investigated the presence and role of OxyR in A. pleuropneumoniae serovar 1-12 reference strains. Transcriptomic analysis was conducted on an oxyR disruption mutant to delineate the biological activities influenced by OxyR. Additionally, specific assays were employed to assess urease activity, catalase expression, ApxI toxin secretion, as well as adhesion and invasion abilities of the oxyR disruption mutant on porcine 3D4/21 and PT cells. A mice challenge experiment was also conducted to evaluate the impact of oxyR inactivation on A. pleuropneumoniae virulence. Results OxyR was identified as a conserved regulator present in A. pleuropneumoniae serovar 1-12 reference strains. Transcriptomic analysis revealed the involvement of OxyR in multiple biological activities. The oxyR disruption resulted in decreased urease activity, elevated catalase expression, enhanced ApxI toxin secretion-attributed to OxyR binding to the apxIBD promoter-and reduced adhesion and invasion abilities on porcine cells. Furthermore, inactivation of oxyR reduced the virulence of A. pleuropneumoniae in a mice challenge experiment. Discussion The findings highlight the pivotal role of OxyR in influencing the virulence mechanisms of A. pleuropneumoniae. The observed effects on various biological activities underscore OxyR as an essential factor contributing to the pathogenicity of this bacterium.
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Affiliation(s)
- Fangfang Guo
- Beijing Key Laboratory for Prevention and Control of Infectious Diseases in Livestock and Poultry, Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
| | - Rong Quan
- Beijing Key Laboratory for Prevention and Control of Infectious Diseases in Livestock and Poultry, Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
| | - Yifang Cui
- Beijing Key Laboratory for Prevention and Control of Infectious Diseases in Livestock and Poultry, Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
| | - Xiaoya Cao
- Beijing Key Laboratory for Prevention and Control of Infectious Diseases in Livestock and Poultry, Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
| | - Tong Wen
- Department of Biology Science and Technology, Baotou Teacher’s College, Baotou, China
| | - Fuzhou Xu
- Beijing Key Laboratory for Prevention and Control of Infectious Diseases in Livestock and Poultry, Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
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Ren G, Zhou X, Long R, Xie M, Kankala RK, Wang S, Zhang YS, Liu Y. Biomedical applications of magnetosomes: State of the art and perspectives. Bioact Mater 2023; 28:27-49. [PMID: 37223277 PMCID: PMC10200801 DOI: 10.1016/j.bioactmat.2023.04.025] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 04/12/2023] [Accepted: 04/29/2023] [Indexed: 05/25/2023] Open
Abstract
Magnetosomes, synthesized by magnetotactic bacteria (MTB), have been used in nano- and biotechnological applications, owing to their unique properties such as superparamagnetism, uniform size distribution, excellent bioavailability, and easily modifiable functional groups. In this review, we first discuss the mechanisms of magnetosome formation and describe various modification methods. Subsequently, we focus on presenting the biomedical advancements of bacterial magnetosomes in biomedical imaging, drug delivery, anticancer therapy, biosensor. Finally, we discuss future applications and challenges. This review summarizes the application of magnetosomes in the biomedical field, highlighting the latest advancements and exploring the future development of magnetosomes.
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Affiliation(s)
- Gang Ren
- Institute of Pharmaceutical Engineering, Huaqiao University, Xiamen, Fujian, 361021, China
- College of Materials Science and Engineering, Huaqiao University, Xiamen, Fujian, 361021, China
| | - Xia Zhou
- Institute of Pharmaceutical Engineering, Huaqiao University, Xiamen, Fujian, 361021, China
- College of Chemical Engineering, Huaqiao University, Xiamen, Fujian, 361021, China
| | - Ruimin Long
- College of Chemical Engineering, Huaqiao University, Xiamen, Fujian, 361021, China
| | - Maobin Xie
- Division of Engineering in Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Cambridge, MA, 02139, USA
- The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan People's Hospital, School of Biomedical Engineering, Guangzhou Medical University, Guangzhou, 511436, China
| | - Ranjith Kumar Kankala
- College of Chemical Engineering, Huaqiao University, Xiamen, Fujian, 361021, China
- Fujian Provincial Key Laboratory of Biochemical Technology, Xiamen, Fujian, 361021, China
| | - Shibin Wang
- Institute of Pharmaceutical Engineering, Huaqiao University, Xiamen, Fujian, 361021, China
- College of Materials Science and Engineering, Huaqiao University, Xiamen, Fujian, 361021, China
- Fujian Provincial Key Laboratory of Biochemical Technology, Xiamen, Fujian, 361021, China
| | - Yu Shrike Zhang
- Division of Engineering in Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Cambridge, MA, 02139, USA
| | - Yuangang Liu
- Institute of Pharmaceutical Engineering, Huaqiao University, Xiamen, Fujian, 361021, China
- College of Chemical Engineering, Huaqiao University, Xiamen, Fujian, 361021, China
- Fujian Provincial Key Laboratory of Biochemical Technology, Xiamen, Fujian, 361021, China
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The Magnetosome Protein, Mms6 from Magnetospirillum magneticum Strain AMB-1, Is a Lipid-Activated Ferric Reductase. Int J Mol Sci 2022; 23:ijms231810305. [PMID: 36142217 PMCID: PMC9499114 DOI: 10.3390/ijms231810305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Revised: 09/02/2022] [Accepted: 09/03/2022] [Indexed: 11/26/2022] Open
Abstract
Magnetosomes of magnetotactic bacteria consist of magnetic nanocrystals with defined morphologies enclosed in vesicles originated from cytoplasmic membrane invaginations. Although many proteins are involved in creating magnetosomes, a single magnetosome protein, Mms6 from Magnetospirillum magneticum strain AMB-1, can direct the crystallization of magnetite nanoparticles in vitro. The in vivo role of Mms6 in magnetosome formation is debated, and the observation that Mms6 binds Fe3+ more tightly than Fe2+ raises the question of how, in a magnetosome environment dominated by Fe3+, Mms6 promotes the crystallization of magnetite, which contains both Fe3+ and Fe2+. Here we show that Mms6 is a ferric reductase that reduces Fe3+ to Fe2+ using NADH and FAD as electron donor and cofactor, respectively. Reductase activity is elevated when Mms6 is integrated into either liposomes or bicelles. Analysis of Mms6 mutants suggests that the C-terminal domain binds iron and the N-terminal domain contains the catalytic site. Although Mms6 forms multimers that involve C-terminal and N-terminal domain interactions, a fusion protein with ubiquitin remains a monomer and displays reductase activity, which suggests that the catalytic site is fully in the monomer. However, the quaternary structure of Mms6 appears to alter the iron binding characteristics of the C-terminal domain. These results are consistent with a hypothesis that Mms6, a membrane protein, promotes the formation of magnetite in vivo by a mechanism that involves reducing iron.
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Biomineralization and biotechnological applications of bacterial magnetosomes. Colloids Surf B Biointerfaces 2022; 216:112556. [PMID: 35605573 DOI: 10.1016/j.colsurfb.2022.112556] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 04/27/2022] [Accepted: 05/07/2022] [Indexed: 01/13/2023]
Abstract
Magnetosomes intracellularly biomineralized by Magnetotactic bacteria (MTB) are membrane-enveloped nanoparticles of the magnetic minerals magnetite (Fe3O4) or greigite (Fe3S4). MTB thrive in oxic-anoxic interface and exhibit magnetotaxis due to the presence of magnetosomes. Because of the unique characteristic and bionavigation inspiration of magnetosomes, MTB has been a subject of study focused on by biologists, medical pharmacologists, geologists, and physicists since the discovery. We herein first briefly review the features of MTB and magnetosomes. The recent insights into the process and mechanism for magnetosome biomineralization including iron uptake, magnetosome membrane invagination, iron mineralization and magnetosome chain assembly are summarized in detail. Additionally, the current research progress in biotechnological applications of magnetosomes is also elucidated, such as drug delivery, MRI image contrast, magnetic hyperthermia, wastewater treatment, and cell separation. This review would expand our understanding of biomineralization and biotechnological applications of bacterial magnetosomes.
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Abstract
Magnetotactic bacteria (MTB) belong to several phyla. This class of microorganisms exhibits the ability of magneto-aerotaxis. MTB synthesize biominerals in organelle-like structures called magnetosomes, which contain single-domain crystals of magnetite (Fe3O4) or greigite (Fe3S4) characterized by a high degree of structural and compositional perfection. Magnetosomes from dead MTB could be preserved in sediments (called fossil magnetosomes or magnetofossils). Under certain conditions, magnetofossils are capable of retaining their remanence for millions of years. This accounts for the growing interest in MTB and magnetofossils in paleo- and rock magnetism and in a wider field of biogeoscience. At the same time, high biocompatibility of magnetosomes makes possible their potential use in biomedical applications, including magnetic resonance imaging, hyperthermia, magnetically guided drug delivery, and immunomagnetic analysis. In this review, we attempt to summarize the current state of the art in the field of MTB research and applications.
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Genome-Wide Screening of Oxidizing Agent Resistance Genes in Escherichia coli. Antioxidants (Basel) 2021; 10:antiox10060861. [PMID: 34072091 PMCID: PMC8228696 DOI: 10.3390/antiox10060861] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Revised: 05/25/2021] [Accepted: 05/26/2021] [Indexed: 01/31/2023] Open
Abstract
The use of oxidizing agents is one of the most favorable approaches to kill bacteria in daily life. However, bacteria have been evolving to survive in the presence of different oxidizing agents. In this study, we aimed to obtain a comprehensive list of genes whose expression can make Escherichiacoli cells resistant to different oxidizing agents. For this purpose, we utilized the ASKA library and performed a genome-wide screening of ~4200 E. coli genes. Hydrogen peroxide (H2O2) and hypochlorite (HOCl) were tested as representative oxidizing agents in this study. To further validate our screening results, we used different E. coli strains as host cells to express or inactivate selected resistance genes individually. More than 100 genes obtained in this screening were not known to associate with oxidative stress responses before. Thus, this study is expected to facilitate both basic studies on oxidative stress and the development of antibacterial agents.
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Sen A, Imlay JA. How Microbes Defend Themselves From Incoming Hydrogen Peroxide. Front Immunol 2021; 12:667343. [PMID: 33995399 PMCID: PMC8115020 DOI: 10.3389/fimmu.2021.667343] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 03/19/2021] [Indexed: 12/02/2022] Open
Abstract
Microbes rely upon iron as a cofactor for many enzymes in their central metabolic processes. The reactive oxygen species (ROS) superoxide and hydrogen peroxide react rapidly with iron, and inside cells they can generate both enzyme and DNA damage. ROS are formed in some bacterial habitats by abiotic processes. The vulnerability of bacteria to ROS is also apparently exploited by ROS-generating host defense systems and bacterial competitors. Phagocyte-derived O 2 - can toxify captured bacteria by damaging unidentified biomolecules on the cell surface; it is unclear whether phagocytic H2O2, which can penetrate into the cell interior, also plays a role in suppressing bacterial invasion. Both pathogenic and free-living microbes activate defensive strategies to defend themselves against incoming H2O2. Most bacteria sense the H2O2via OxyR or PerR transcription factors, whereas yeast uses the Grx3/Yap1 system. In general these regulators induce enzymes that reduce cytoplasmic H2O2 concentrations, decrease the intracellular iron pools, and repair the H2O2-mediated damage. However, individual organisms have tailored these transcription factors and their regulons to suit their particular environmental niches. Some bacteria even contain both OxyR and PerR, raising the question as to why they need both systems. In lab experiments these regulators can also respond to nitric oxide and disulfide stress, although it is unclear whether the responses are physiologically relevant. The next step is to extend these studies to natural environments, so that we can better understand the circumstances in which these systems act. In particular, it is important to probe the role they may play in enabling host infection by microbial pathogens.
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Affiliation(s)
| | - James A. Imlay
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
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