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Anjou C, Lotoux A, Morvan C, Martin-Verstraete I. From ubiquity to specificity: The diverse functions of bacterial thioredoxin systems. Environ Microbiol 2024; 26:e16668. [PMID: 38899743 DOI: 10.1111/1462-2920.16668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Accepted: 05/24/2024] [Indexed: 06/21/2024]
Abstract
The thioredoxin (Trx) system, found universally, is responsible for the regeneration of reversibly oxidized protein thiols in living cells. This system is made up of a Trx and a Trx reductase, and it plays a central role in maintaining thiol-based redox homeostasis by reducing oxidized protein thiols, such as disulfide bonds in proteins. Some Trxs also possess a chaperone function that is independent of thiol-disulfide exchange, in addition to their thiol-disulfide reductase activity. These two activities of the Trx system are involved in numerous physiological processes in bacteria. This review describes the diverse physiological roles of the Trx system that have emerged throughout bacterial evolution. The Trx system is essential for responding to oxidative and nitrosative stress. Beyond this primary function, the Trx system also participates in redox regulation and signal transduction, and in controlling metabolism, motility, biofilm formation, and virulence. This range of functions has evolved alongside the diversity of bacterial lifestyles and their specific constraints. This evolution can be characterized by the multiplication of the systems and by the specialization of cofactors or targets to adapt to the constraints of atypical lifestyles, such as photosynthesis, insect endosymbiosis, or spore-forming bacteria.
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Affiliation(s)
- Cyril Anjou
- Institut Pasteur, Université Paris Cité, UMR CNRS 6047, Laboratoire Pathogenèse des Bactéries Anaérobies, Paris, France
| | - Aurélie Lotoux
- Institut Pasteur, Université Paris Cité, UMR CNRS 6047, Laboratoire Pathogenèse des Bactéries Anaérobies, Paris, France
| | - Claire Morvan
- Institut Pasteur, Université Paris Cité, UMR CNRS 6047, Laboratoire Pathogenèse des Bactéries Anaérobies, Paris, France
| | - Isabelle Martin-Verstraete
- Institut Pasteur, Université Paris Cité, UMR CNRS 6047, Laboratoire Pathogenèse des Bactéries Anaérobies, Paris, France
- Institut Universitaire de France, Paris, France
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Díez-Sainz E, Milagro FI, Aranaz P, Riezu-Boj JI, Lorente-Cebrián S. MicroRNAs from edible plants reach the human gastrointestinal tract and may act as potential regulators of gene expression. J Physiol Biochem 2024:10.1007/s13105-024-01023-0. [PMID: 38662188 DOI: 10.1007/s13105-024-01023-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 04/05/2024] [Indexed: 04/26/2024]
Abstract
MicroRNAs (miRNAs) are small single-stranded non-coding RNA molecules that regulate gene expression at the post-transcriptional level. A cross-kingdom regulatory function has been unveiled for plant miRNAs (xenomiRs), which could shape inter-species interactions of plants with other organisms (bacteria and humans) and thus, be key functional molecules of plant-based food in mammals. However, discrepancies regarding the stability and bioavailability of dietary plant miRNAs on the host cast in doubt whether these molecules could have a significant impact on human physiology. The aim of the present study was to identify miRNAs in edible plants and determine their bioavailability on humans after an acute intake of plant-based products. It was found that plant food, including fruits, vegetables and greens, nuts, legumes, and cereals, contains a wide range of miRNAs. XenomiRs miR156e, miR159 and miR162 were detected in great abundance in edible plants and were present among many plant foods, and thus, they were selected as candidates to analyse their bioavailability in humans. These plant miRNAs resisted cooking processes (heat-treatments) and their relative presence increased in faeces after and acute intake of plant-based foods, although they were not detected in serum. Bioinformatic analysis revealed that these miRNAs could potentially target human and bacterial genes involved in processes such as cell signalling and metabolism. In conclusion, edible plants contain miRNAs, such as miR156e, miR159 and miR162, that could resist degradation during cooking and digestion and reach the distal segments of the gastrointestinal tract. Nevertheless, strategies should be developed to improve their absorption to potentially reach host tissues and organs and modulate human physiology.
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Affiliation(s)
- Ester Díez-Sainz
- Department of Nutrition, Food Science and Physiology/Center for Nutrition Research, Faculty of Pharmacy and Nutrition, University of Navarra, 31008, Pamplona, Spain
| | - Fermín I Milagro
- Department of Nutrition, Food Science and Physiology/Center for Nutrition Research, Faculty of Pharmacy and Nutrition, University of Navarra, 31008, Pamplona, Spain.
- Navarra Institute for Health Research (IdiSNA), 31008, Pamplona, Spain.
- Centro de Investigación Biomédica en Red Fisiopatología de La Obesidad y Nutrición (CIBERobn), Instituto de Salud Carlos III, 28029, Madrid, Spain.
| | - Paula Aranaz
- Department of Nutrition, Food Science and Physiology/Center for Nutrition Research, Faculty of Pharmacy and Nutrition, University of Navarra, 31008, Pamplona, Spain
- Navarra Institute for Health Research (IdiSNA), 31008, Pamplona, Spain
| | - José I Riezu-Boj
- Department of Nutrition, Food Science and Physiology/Center for Nutrition Research, Faculty of Pharmacy and Nutrition, University of Navarra, 31008, Pamplona, Spain
- Navarra Institute for Health Research (IdiSNA), 31008, Pamplona, Spain
| | - Silvia Lorente-Cebrián
- Department of Pharmacology, Physiology and Legal and Forensic Medicine, Faculty of Health and Sport Science, University of Zaragoza, 50009, Saragossa, Spain
- Instituto Agroalimentario de Aragón-IA2, Universidad de Zaragoza-CITA, 50013, Saragossa, Spain
- Aragón Health Research Institute (IIS-Aragon), 50009, Saragossa, Spain
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Sun H, Si F, Zhao X, Li F, Qi G. The cellular redox state in Bacillus amyloliquefaciens WH1 affects biofilm formation indirectly in a surfactant direct manner. J Basic Microbiol 2023. [PMID: 37189223 DOI: 10.1002/jobm.202300064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 03/30/2023] [Accepted: 04/27/2023] [Indexed: 05/17/2023]
Abstract
Surfactin is a signal to trigger biofilm formation against harsh environments. Generally, harsh environments can result in change of the cellular redox state to induce biofilm formation, but we know little about whether the cellular redox state influences biofilm formation via surfactin. Here, the reductant glucose could reduce surfactin and enhance biofilm formation by a surfactin-indirect way. The oxidant H2 O2 led to a decrease of surfactin accompanying with weakened biofilm formation. Spx and PerR were both necessary for surfactin production and biofilm formation. H2 O2 improved surfactin production but inhibited biofilm formation by a surfactin-indirect manner in Δspx, while it reduced surfactin production without obvious influence on biofilm formation in ΔperR. The ability against H2 O2 stress was enhanced in Δspx, but weakened in ΔperR. Thereby, PerR was favorable for resisting oxidative stress, while Spx played a negative role in this action. Knockout and compensation of rex also supported that the cells could form biofilm by a surfactin-indirect way. Collectively, surfactin is not a unique signal to trigger biofilm formation, and the cellular redox state can influence biofilm formation by a surfactin-direct or -indirect way in Bacillus amyloliquefaciens WH1.
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Affiliation(s)
- Huiwan Sun
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Fengmei Si
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Xiuyun Zhao
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Feng Li
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Gaofu Qi
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
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Li T, Lu Y, Zhang H, Wang L, Beier RC, Jin Y, Wang W, Li H, Hou X. Antibacterial Activity and Membrane-Targeting Mechanism of Aloe-Emodin Against Staphylococcus epidermidis. Front Microbiol 2021; 12:621866. [PMID: 34484130 PMCID: PMC8415635 DOI: 10.3389/fmicb.2021.621866] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 07/26/2021] [Indexed: 11/17/2022] Open
Abstract
The emergence of multidrug-resistant Staphylococcus epidermidis (S. epidermidis) dwarfs the current antibiotic development and calls for the discovery of new antibacterial agents. Aloe-emodin is a plant-derived compound that holds promise to battle against these strains. This work reports the antimicrobial activity of aloe-emodin against S. epidermidis and other Gram-positive pathogenic species, manifesting minimum inhibitory concentrations (MICs) and minimum bactericidal concentration (MBCs) around 4–32 and 32–128 μg/mL, respectively. For Gram-negative bacteria tested, the MICs and MBCs of aloe-emodin were 128–256 and above 1024 μg/mL, respectively. Aloe-emodin at the MBC for 4 h eradicated 96.9% of S. epidermidis cells. Aloe-emodin treatment led to deformities in the morphology of S. epidermidis cells and the destroy of the selective permeability of the cell membranes. Analysis of the transcriptional profiles of aloe-emodin-treated cells revealed changes of genes involved in sulfur metabolism, L-lysine and peptidoglycan biosynthesis, and biofilm formation. Aloe-emodin therefore can safely control Gram-positive bacterial infections and proves to target the bacterial outer membrane.
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Affiliation(s)
- Tao Li
- Shanghai Veterinary Research Institute, CAAS, Shanghai, China
| | - Yan Lu
- Beijing Key Laboratory of Chinese Veterinary Medicine, Department of Veterinary Medicine, National Demonstration Center for Experimental Animal Education, Beijing University of Agriculture, Beijing, China
| | - Hua Zhang
- Beijing Key Laboratory of Chinese Veterinary Medicine, Department of Veterinary Medicine, National Demonstration Center for Experimental Animal Education, Beijing University of Agriculture, Beijing, China
| | - Lei Wang
- Beijing Huafukang Bioscience Co., Ltd., Beijing, China
| | - Ross C Beier
- Food and Feed Safety Research Unit, Southern Plains Agricultural Research Center, Agricultural Research Service, United States Department of Agriculture, College Station, TX, United States
| | - Yajie Jin
- Shanghai Veterinary Research Institute, CAAS, Shanghai, China
| | - Wenjing Wang
- Shanghai Veterinary Research Institute, CAAS, Shanghai, China
| | - Huanrong Li
- Beijing Key Laboratory of Chinese Veterinary Medicine, Department of Veterinary Medicine, National Demonstration Center for Experimental Animal Education, Beijing University of Agriculture, Beijing, China
| | - Xiaolin Hou
- Beijing Key Laboratory of Chinese Veterinary Medicine, Department of Veterinary Medicine, National Demonstration Center for Experimental Animal Education, Beijing University of Agriculture, Beijing, China
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Abstract
Biofilm dispersion is the final stage of biofilm development, during which biofilm cells actively escape from biofilms in response to deteriorating conditions within the biofilm. Biofilm dispersion allows cells to spread to new locations and form new biofilms in better locations. However, dispersal mechanisms have been elucidated only in a limited number of bacteria. Here, we investigated biofilm dispersion in Bacillus subtilis. Biofilm dispersion was clearly observed when B. subtilis was grown under static conditions in modified LB medium containing glycerol and manganese. Biofilm dispersion was synergistically caused by two mechanisms: decreased expression of the epsA operon encoding exopolysaccharide synthetases and the induction of sporulation. Indeed, constitutive expression of the epsA operon in the sporulation-defective ΔsigK mutant prevented biofilm dispersion. The addition of calcium to the medium prevented biofilm dispersion without significantly affecting the expression of the epsA operon and sporulation genes. In synthetic medium, eliminating calcium did not prevent the expression of biofilm matrix genes and, thereby, biofilm formation, but it attenuated biofilm architecture. These results indicate that calcium structurally stabilizes biofilms and causes resistance to biofilm dispersion mechanisms. Sporulation-dependent biofilm dispersion required the spoVF operon, encoding dipicolinic acid (DPA) synthase. During sporulation, an enormous amount of DPA is synthesized and stored in spores as a chelate with calcium. We speculate that, during sporulation, calcium bound to biofilm matrix components may be transported to spores as a calcium-DPA complex, which weakens biofilm structure and leads to biofilm dispersion. IMPORTANCE Bacteria growing as biofilms are notoriously difficult to eradicate and sometimes pose serious threats to public health. Bacteria escape from biofilms by degrading them when biofilm conditions deteriorate. This process, called biofilm dispersion, has been studied as a promising strategy for safely controlling biofilms. However, the regulation and mechanism of biofilm dispersion has been elucidated only in a limited number of bacteria. Here, we identified two biofilm dispersion mechanisms in the Gram-positive, spore-forming bacterium Bacillus subtilis. The addition of calcium to the medium stabilized biofilms and caused resistance to dispersal mechanisms. Our findings provide new insights into biofilm dispersion and biofilm control.
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Roy R, You RI, Chang CH, Yang CY, Lin NT. Carboxy-Terminal Processing Protease Controls Production of Outer Membrane Vesicles and Biofilm in Acinetobacter baumannii. Microorganisms 2021; 9:microorganisms9061336. [PMID: 34203028 PMCID: PMC8234194 DOI: 10.3390/microorganisms9061336] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 06/14/2021] [Accepted: 06/17/2021] [Indexed: 12/12/2022] Open
Abstract
Carboxy-terminal processing protease (Ctp) is a serine protease that controls multiple cellular processes through posttranslational modification of proteins. Acinetobacter baumannii ATCC 17978 ctp mutant, namely MR14, is known to cause cell wall defects and autolysis. The objective of this study was to investigate the role of ctp mutation-driven autolysis in regulating biofilms in A. baumannii and to evaluate the vesiculation caused by cell wall defects. We found that in A. baumannii, Ctp is localized in the cytoplasmic membrane, and loss of Ctp function enhances the biofilm-forming ability of A. baumannii. Quantification of the matrix components revealed that extracellular DNA (eDNA) and proteins were the chief constituents of MR14 biofilm, and the transmission electron microscopy further indicated the presence of numerous dead cells compared with ATCC 17978. The large number of MR14 dead cells is potentially the result of compromised outer membrane integrity, as demonstrated by its high sensitivity to sodium dodecyl sulfate (SDS) and ethylenediaminetetraacetic acid (EDTA). MR14 also exhibited the hypervesiculation phenotype, producing outer-membrane vesicles (OMVs) of large mean size. The MR14 OMVs were more cytotoxic toward A549 cells than ATCC 17978 OMVs. Our overall results indicate that A. baumanniictp negatively controls pathogenic traits through autolysis and OMV biogenesis.
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Affiliation(s)
- Rakesh Roy
- Institute of Medical Sciences, Tzu Chi University, No. 701, Sec. 3, Zhongyang Rd., Hualien 97004, Taiwan;
| | - Ren-In You
- Department of Laboratory Medicine and Biotechnology, Tzu Chi University, No. 701, Sec. 3, Zhongyang Rd., Hualien 97004, Taiwan;
| | - Chan-Hua Chang
- Institute of Molecular Biology, National Chung Hsing University, Taichung 40227, Taiwan;
| | - Chiou-Ying Yang
- Institute of Molecular Biology, National Chung Hsing University, Taichung 40227, Taiwan;
- Correspondence: (C.-Y.Y.); (N.-T.L.); Tel.: +886-3-856 5301 (ext. 2080) (N.-T.L.); Fax: +886-3-8566724 (N.-T.L.)
| | - Nien-Tsung Lin
- Institute of Medical Sciences, Tzu Chi University, No. 701, Sec. 3, Zhongyang Rd., Hualien 97004, Taiwan;
- Department of Microbiology, School of Medicine, Tzu Chi University, No. 701, Sec. 3, Zhongyang Rd., Hualien 97004, Taiwan
- Correspondence: (C.-Y.Y.); (N.-T.L.); Tel.: +886-3-856 5301 (ext. 2080) (N.-T.L.); Fax: +886-3-8566724 (N.-T.L.)
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Sharipova MR, Mardanova AM, Rudakova NL, Pudova DS. Bistability and Formation of the Biofilm Matrix as Adaptive Mechanisms during the Stationary Phase of Bacillus subtilis. Microbiology (Reading) 2021. [DOI: 10.1134/s002626172006017x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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Role of Glutamate Synthase in Biofilm Formation by Bacillus subtilis. J Bacteriol 2020; 202:JB.00120-20. [PMID: 32393519 DOI: 10.1128/jb.00120-20] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 05/04/2020] [Indexed: 11/20/2022] Open
Abstract
Bacillus subtilis forms robust biofilms in the presence of large amounts of carbon sources, such as glycerol. However, little is known about the importance of the metabolic systems, or the relationship between metabolic systems and regulatory systems, involved in biofilm formation. Glutamate synthase, encoded by gltAB, is an enzyme that converts 2-ketoglutarate (a tricarboxylic acid [TCA] cycle intermediate) and glutamine into glutamate, which is a general amino group donor in metabolism. Here, we show that a ΔgltA mutant exhibited early arrest of biofilm formation in complex medium containing glycerol. This phenotype was not due to glutamate auxotrophy. Consistent with its biofilm formation phenotype, the ΔgltA mutant exhibited an early decrease in expression of the epsA and tapA operons, which are responsible for production of biofilm matrix polymers. This resulted from decreased activity of their regulator, Spo0A, as evidenced by reduced expression of other Spo0A-regulated genes in the ΔgltA mutant. The ΔgltA mutation prevented biofilm formation only in the presence of large amounts of glycerol. Moreover, limited expression of citrate synthase (but not other TCA enzymes) restored biofilm-forming ability to the ΔgltA mutant. These results indicate that the ΔgltA mutant accumulates an inhibitory intermediate (citrate) in the TCA cycle in the presence of large amounts of glycerol. The ΔgltA mutant formed biofilms when excess iron was added to the medium. Taken together, the data suggest that accumulation of citrate ions by the ΔgltA mutant causes iron shortage due to chelation, which prevents activation of Spo0A and causes defective biofilm formation.IMPORTANCE Bacillus subtilis, a model organism for bacterial biofilm formation, forms robust biofilms in a medium-dependent manner. Although the regulatory network that controls biofilm formation has been well studied, the importance of the underlying metabolic systems remains to be elucidated. The present study demonstrates that a metabolic disorder in a well-conserved metabolic system causes accumulation of an inhibitory metabolic intermediate that prevents activation of the system that regulates biofilm formation. These findings increase our understanding of the coordination between cellular metabolic status and the regulatory networks governing biofilm formation.
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Schäfer H, Turgay K. Spx, a versatile regulator of the Bacillus subtilis stress response. Curr Genet 2019; 65:871-876. [DOI: 10.1007/s00294-019-00950-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 02/26/2019] [Accepted: 02/28/2019] [Indexed: 01/16/2023]
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