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Rajova J, Zeman M, Seidlerova Z, Vlasatikova L, Matiasovicova J, Sebkova A, Faldynova M, Prikrylova H, Karasova D, Crhanova M, Kulich P, Babak V, Volf J, Rychlik I. In Vivo Expression of Chicken Gut Anaerobes Identifies Carbohydrate- or Amino Acid-Utilising, Motile or Type VI Secretion System-Expressing Bacteria. Int J Mol Sci 2024; 25:6505. [PMID: 38928209 PMCID: PMC11204068 DOI: 10.3390/ijms25126505] [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: 05/07/2024] [Revised: 06/05/2024] [Accepted: 06/09/2024] [Indexed: 06/28/2024] Open
Abstract
Complex gut microbiota increases chickens' resistance to enteric pathogens. However, the principles of this phenomenon are not understood in detail. One of the possibilities for how to decipher the role of gut microbiota in chickens' resistance to enteric pathogens is to systematically characterise the gene expression of individual gut microbiota members colonising the chicken caecum. To reach this aim, newly hatched chicks were inoculated with bacterial species whose whole genomic sequence was known. Total protein purified from the chicken caecum was analysed by mass spectrometry, and the obtained spectra were searched against strain-specific protein databases generated from known genomic sequences. Campylobacter jejuni, Phascolarctobacterium sp. and Sutterella massiliensis did not utilise carbohydrates when colonising the chicken caecum. On the other hand, Bacteroides, Mediterranea, Marseilla, Megamonas, Megasphaera, Bifidobacterium, Blautia, Escherichia coli and Succinatimonas fermented carbohydrates. C. jejuni was the only motile bacterium, and Bacteroides mediterraneensis expressed the type VI secretion system. Classification of in vivo expression is key for understanding the role of individual species in complex microbial populations colonising the intestinal tract. Knowledge of the expression of motility, the type VI secretion system, and preference for carbohydrate or amino acid fermentation is important for the selection of bacteria for defined competitive exclusion products.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | - Ivan Rychlik
- Veterinary Research Institute, CZ6210 Brno, Czech Republic; (J.R.); (M.Z.); (Z.S.); (L.V.); (J.M.); (A.S.); (M.F.); (H.P.); (D.K.); (M.C.); (P.K.); (V.B.); (J.V.)
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2
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Anjou C, Lotoux A, Zhukova A, Royer M, Caulat LC, Capuzzo E, Morvan C, Martin-Verstraete I. The multiplicity of thioredoxin systems meets the specific lifestyles of Clostridia. PLoS Pathog 2024; 20:e1012001. [PMID: 38330058 PMCID: PMC10880999 DOI: 10.1371/journal.ppat.1012001] [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: 09/28/2023] [Revised: 02/21/2024] [Accepted: 01/26/2024] [Indexed: 02/10/2024] Open
Abstract
Cells are unceasingly confronted by oxidative stresses that oxidize proteins on their cysteines. The thioredoxin (Trx) system, which is a ubiquitous system for thiol and protein repair, is composed of a thioredoxin (TrxA) and a thioredoxin reductase (TrxB). TrxAs reduce disulfide bonds of oxidized proteins and are then usually recycled by a single pleiotropic NAD(P)H-dependent TrxB (NTR). In this work, we first analyzed the composition of Trx systems across Bacteria. Most bacteria have only one NTR, but organisms in some Phyla have several TrxBs. In Firmicutes, multiple TrxBs are observed only in Clostridia, with another peculiarity being the existence of ferredoxin-dependent TrxBs. We used Clostridioides difficile, a pathogenic sporulating anaerobic Firmicutes, as a model to investigate the biological relevance of TrxB multiplicity. Three TrxAs and three TrxBs are present in the 630Δerm strain. We showed that two systems are involved in the response to infection-related stresses, allowing the survival of vegetative cells exposed to oxygen, inflammation-related molecules and bile salts. A fourth TrxB copy present in some strains also contributes to the stress-response arsenal. One of the conserved stress-response Trx system was found to be present both in vegetative cells and in the spores and is under a dual transcriptional control by vegetative cell and sporulation sigma factors. This Trx system contributes to spore survival to hypochlorite and ensure proper germination in the presence of oxygen. Finally, we found that the third Trx system contributes to sporulation through the recycling of the glycine-reductase, a Stickland pathway enzyme that allows the consumption of glycine and contributes to sporulation. Altogether, we showed that Trx systems are produced under the control of various regulatory signals and respond to different regulatory networks. The multiplicity of Trx systems and the diversity of TrxBs most likely meet specific needs of Clostridia in adaptation to strong stress exposure, sporulation and Stickland pathways.
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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
| | - Anna Zhukova
- Institut Pasteur, Université Paris Cité, Bioinformatics and Biostatistics Hub, Paris, France
| | - Marie Royer
- Institut Pasteur, Université Paris Cité, UMR CNRS 6047, Laboratoire Pathogenèse des Bactéries Anaérobies, Paris, France
| | - Léo C. Caulat
- Institut Pasteur, Université Paris Cité, UMR CNRS 6047, Laboratoire Pathogenèse des Bactéries Anaérobies, Paris, France
| | - Elena Capuzzo
- 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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3
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Zong W, Friedman ES, Allu SR, Firrman J, Tu V, Daniel SG, Bittinger K, Liu L, Vinogradov SA, Wu GD. Disruption of intestinal oxygen balance in acute colitis alters the gut microbiome. Gut Microbes 2024; 16:2361493. [PMID: 38958039 PMCID: PMC11225921 DOI: 10.1080/19490976.2024.2361493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 05/24/2024] [Indexed: 07/04/2024] Open
Abstract
The juxtaposition of well-oxygenated intestinal colonic tissue with an anerobic luminal environment supports a fundamentally important relationship that is altered in the setting of intestinal injury, a process likely to be relevant to diseases such as inflammatory bowel disease. Herein, using two-color phosphorometry to non-invasively quantify both intestinal tissue and luminal oxygenation in real time, we show that intestinal injury induced by DSS colitis reduces intestinal tissue oxygenation in a spatially defined manner and increases the flux of oxygen from the tissue into the gut lumen. By characterizing the composition of the microbiome in both DSS colitis-affected gut and in a bioreactor containing a stable human fecal community exposed to microaerobic conditions, we provide evidence that the increased flux of oxygen into the gut lumen augments glycan degrading bacterial taxa rich in glycoside hydrolases which are known to inhabit gut mucosal surface. Continued disruption of the intestinal mucus barrier through such a mechanism may play a role in the perpetuation of the intestinal inflammatory process.
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Affiliation(s)
- Wenjing Zong
- Division of Gastroenterology, Hepatology, and Nutrition, The Children’s Hospital of Philadelphia, Philadelphia, PA ,USA
| | - Elliot S. Friedman
- Department of Gastroenterology & Hepatology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Srinivasa Rao Allu
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA, USA
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Jenni Firrman
- Dairy and Functional Foods Research Unit, Eastern Regional Research Center, Agricultural Research Service, US Department of Agriculture, Wyndmoor, PA, USA
| | - Vincent Tu
- Division of Gastroenterology, Hepatology, and Nutrition, The Children’s Hospital of Philadelphia, Philadelphia, PA ,USA
| | - Scott G. Daniel
- Division of Gastroenterology, Hepatology, and Nutrition, The Children’s Hospital of Philadelphia, Philadelphia, PA ,USA
| | - Kyle Bittinger
- Division of Gastroenterology, Hepatology, and Nutrition, The Children’s Hospital of Philadelphia, Philadelphia, PA ,USA
| | - LinShu Liu
- Dairy and Functional Foods Research Unit, Eastern Regional Research Center, Agricultural Research Service, US Department of Agriculture, Wyndmoor, PA, USA
| | - Sergei A. Vinogradov
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA, USA
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Gary D. Wu
- Department of Gastroenterology & Hepatology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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4
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Keitel L, Braun K, Finger M, Kosfeld U, Yordanov S, Büchs J. Carbon dioxide and trace oxygen concentrations impact growth and product formation of the gut bacterium Phocaeicola vulgatus. BMC Microbiol 2023; 23:391. [PMID: 38062358 PMCID: PMC10701953 DOI: 10.1186/s12866-023-03127-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 11/17/2023] [Indexed: 12/18/2023] Open
Abstract
BACKGROUND The promising yet barely investigated anaerobic species Phocaeicola vulgatus (formerly Bacteroides vulgatus) plays a vital role for human gut health and effectively produces organic acids. Among them is succinate, a building block for high-value-added chemicals. Cultivating anaerobic bacteria is challenging, and a detailed understanding of P. vulgatus growth and metabolism is required to improve succinate production. One significant aspect is the influence of different gas concentrations. CO2 is required for the growth of P. vulgatus. However, it is a greenhouse gas that should not be wasted. Another highly interesting aspect is the sensitivity of P. vulgatus towards O2. In this work, the effects of varying concentrations of both gases were studied in the in-house developed Respiratory Activity MOnitoring System (RAMOS), which provides online monitoring of CO2, O2, and pressure under gassed conditions. The RAMOS was combined with a gas mixing system to test CO2 and O2 concentrations in a range of 0.25-15.0 vol% and 0.0-2.5 vol%, respectively. RESULTS Changing the CO2 concentration in the gas supply revealed a CO2 optimum of 3.0 vol% for total organic acid production and 15.0 vol% for succinate production. It was demonstrated that the organic acid composition changed depending on the CO2 concentration. Furthermore, unrestricted growth of P. vulgatus up to an O2 concentration of 0.7 vol% in the gas supply was proven. The viability decreased rapidly at concentrations larger than or equal to 1.3 vol% O2. CONCLUSIONS The study showed that P. vulgatus requires little CO2, has a distinct O2 tolerance and is therefore well suited for industrial applications.
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Affiliation(s)
- Laura Keitel
- Chair of Biochemical Engineering (AVT.BioVT), RWTH Aachen University, Forckenbeckstraße 51, 52074, Aachen, Germany
| | - Kristina Braun
- Chair of Biochemical Engineering (AVT.BioVT), RWTH Aachen University, Forckenbeckstraße 51, 52074, Aachen, Germany
| | - Maurice Finger
- Chair of Biochemical Engineering (AVT.BioVT), RWTH Aachen University, Forckenbeckstraße 51, 52074, Aachen, Germany
| | - Udo Kosfeld
- Chair of Biochemical Engineering (AVT.BioVT), RWTH Aachen University, Forckenbeckstraße 51, 52074, Aachen, Germany
| | - Stanislav Yordanov
- Chair of Biochemical Engineering (AVT.BioVT), RWTH Aachen University, Forckenbeckstraße 51, 52074, Aachen, Germany
| | - Jochen Büchs
- Chair of Biochemical Engineering (AVT.BioVT), RWTH Aachen University, Forckenbeckstraße 51, 52074, Aachen, Germany.
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5
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Botin T, Ramirez-Chamorro L, Vidic J, Langella P, Martin-Verstraete I, Chatel JM, Auger S. The Tolerance of Gut Commensal Faecalibacterium to Oxidative Stress Is Strain Dependent and Relies on Detoxifying Enzymes. Appl Environ Microbiol 2023; 89:e0060623. [PMID: 37382539 PMCID: PMC10370306 DOI: 10.1128/aem.00606-23] [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: 04/12/2023] [Accepted: 06/12/2023] [Indexed: 06/30/2023] Open
Abstract
Obligate anaerobic bacteria in genus Faecalibacterium are among the most dominant taxa in the colon of healthy individuals and contribute to intestinal homeostasis. A decline in the abundance of this genus is associated with the occurrence of various gastrointestinal disorders, including inflammatory bowel diseases. In the colon, these diseases are accompanied by an imbalance between the generation and elimination of reactive oxygen species (ROS), and oxidative stress is closely linked to disruptions in anaerobiosis. In this work, we explored the impact of oxidative stress on several strains of faecalibacteria. An in silico analysis of complete genomes of faecalibacteria revealed the presence of genes encoding O2- and/or ROS-detoxifying enzymes, including flavodiiron proteins, rubrerythrins, reverse rubrerythrins, superoxide reductases, and alkyl peroxidase. However, the presence and the number of these detoxification systems varied greatly among faecalibacteria. These results were confirmed by O2 stress survival tests, in which we found that strains differed widely in their sensitivity. We showed the protective role of cysteine, which limited the production of extracellular O2•- and improved the survival of Faecalibacterium longum L2-6 under high O2 tension. In the strain F. longum L2-6, we observed that the expression of genes encoding detoxifying enzymes was upregulated in the response to O2 or H2O2 stress but with different patterns of regulation. Based on these results, we propose a first model of the gene regulatory network involved in the response to oxidative stress in F. longum L2-6. IMPORTANCE Commensal bacteria in the genus Faecalibacterium have been proposed for use as next-generation probiotics, but efforts to cultivate and exploit the potential of these strains have been limited by their sensitivity to O2. More broadly, little is known about how commensal and health-associated bacterial species in the human microbiome respond to the oxidative stress that occurs as a result of inflammation in the colon. In this work, we provide insights regarding the genes that encode potential mechanisms of protection against O2 or ROS stress in faecalibacteria, which may facilitate future advances in work with these important bacteria.
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Affiliation(s)
- Tatiana Botin
- Université Paris Saclay, INRAE, AgroParisTech, UMR1319, MICALIS, Jouy-en-Josas, France
| | - Luis Ramirez-Chamorro
- Université Paris Saclay, INRAE, AgroParisTech, UMR1319, MICALIS, Jouy-en-Josas, France
| | - Jasmina Vidic
- Université Paris Saclay, INRAE, AgroParisTech, UMR1319, MICALIS, Jouy-en-Josas, France
| | - Philippe Langella
- Université Paris Saclay, INRAE, AgroParisTech, UMR1319, MICALIS, Jouy-en-Josas, France
| | - Isabelle Martin-Verstraete
- Institut Pasteur, Université Paris Cité, UMR CNRS 6047, Laboratoire Pathogénèse des Bactéries Anaérobies, Paris, France
- Institut Universitaire de France, Paris, France
| | - Jean-Marc Chatel
- Université Paris Saclay, INRAE, AgroParisTech, UMR1319, MICALIS, Jouy-en-Josas, France
| | - Sandrine Auger
- Université Paris Saclay, INRAE, AgroParisTech, UMR1319, MICALIS, Jouy-en-Josas, France
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6
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Tawk C, Lim B, Bencivenga-Barry NA, Lees HJ, Ramos RJF, Cross J, Goodman AL. Infection leaves a genetic and functional mark on the gut population of a commensal bacterium. Cell Host Microbe 2023; 31:811-826.e6. [PMID: 37119822 PMCID: PMC10197903 DOI: 10.1016/j.chom.2023.04.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 03/04/2023] [Accepted: 04/04/2023] [Indexed: 05/01/2023]
Abstract
Gastrointestinal infection changes microbiome composition and gene expression. In this study, we demonstrate that enteric infection also promotes rapid genetic adaptation in a gut commensal. Measurements of Bacteroides thetaiotaomicron population dynamics within gnotobiotic mice reveal that these populations are relatively stable in the absence of infection, and the introduction of the enteropathogen Citrobacter rodentium reproducibly promotes rapid selection for a single-nucleotide variant with increased fitness. This mutation promotes resistance to oxidative stress by altering the sequence of a protein, IctA, that is essential for fitness during infection. We identified commensals from multiple phyla that attenuate the selection of this variant during infection. These species increase the levels of vitamin B6 in the gut lumen. Direct administration of this vitamin is sufficient to significantly reduce variant expansion in infected mice. Our work demonstrates that a self-limited enteric infection can leave a stable mark on resident commensal populations that increase fitness during infection.
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Affiliation(s)
- Caroline Tawk
- Department of Microbial Pathogenesis and Microbial Sciences Institute, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Bentley Lim
- Department of Microbial Pathogenesis and Microbial Sciences Institute, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Natasha A Bencivenga-Barry
- Department of Microbial Pathogenesis and Microbial Sciences Institute, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Hannah J Lees
- The Donald B. and Catherine C. Marron Cancer Metabolism Center, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Ruben J F Ramos
- The Donald B. and Catherine C. Marron Cancer Metabolism Center, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Justin Cross
- The Donald B. and Catherine C. Marron Cancer Metabolism Center, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Andrew L Goodman
- Department of Microbial Pathogenesis and Microbial Sciences Institute, Yale University School of Medicine, New Haven, CT 06510, USA.
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7
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Okabe S, Ye S, Lan X, Nukada K, Zhang H, Kobayashi K, Oshiki M. Oxygen tolerance and detoxification mechanisms of highly enriched planktonic anaerobic ammonium-oxidizing (anammox) bacteria. ISME COMMUNICATIONS 2023; 3:45. [PMID: 37137967 PMCID: PMC10156729 DOI: 10.1038/s43705-023-00251-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 04/11/2023] [Accepted: 04/19/2023] [Indexed: 05/05/2023]
Abstract
Oxygen is a key regulatory factor of anaerobic ammonium oxidation (anammox). Although the inhibitory effect of oxygen is evident, a wide range of oxygen sensitivities of anammox bacteria have been reported so far, which makes it difficult to model the marine nitrogen loss and design anammox-based technologies. Here, oxygen tolerance and detoxification mechanisms of four genera of anammox bacteria; one marine species ("Ca. Scalindua sp.") and four freshwater anammox species ("Ca. Brocadia sinica", "Ca. Brocadia sapporoensis", "Ca. Jettenia caeni", and "Ca. Kuenenia stuttgartiensis") were determined and then related to the activities of anti-oxidative enzymes. Highly enriched planktonic anammox cells were exposed to various levels of oxygen, and oxygen inhibition kinetics (50% inhibitory concentration (IC50) and upper O2 limits (DOmax) of anammox activity) were quantitatively determined. A marine anammox species, "Ca. Scalindua sp.", exhibited much higher oxygen tolerance capability (IC50 = 18.0 µM and DOmax = 51.6 µM) than freshwater species (IC50 = 2.7-4.2 µM and DOmax = 10.9-26.6 µM). The upper DO limit of "Ca. Scalindua sp." was much higher than the values reported so far (~20 µM). Furthermore, the oxygen inhibition was reversible even after exposed to ambient air for 12-24 h. The comparative genome analysis confirmed that all anammox species commonly possess the genes considered to function for reduction of O2, superoxide anion (O2•-), and H2O2. However, the superoxide reductase (Sor)-peroxidase dependent detoxification system alone may not be sufficient for cell survival under microaerobic conditions. Despite the fact that anaerobes normally possess no or little superoxide dismutase (Sod) or catalase (Cat), only Scalindua exhibited high Sod activity of 22.6 ± 1.9 U/mg-protein with moderate Cat activity of 1.6 ± 0.7 U/mg-protein, which was consistent with the genome sequence analysis. This Sod-Cat dependent detoxification system could be responsible for the higher O2 tolerance of Scalindua than other freshwater anammox species lacking the Sod activity.
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Affiliation(s)
- Satoshi Okabe
- Department of Environmental Engineering, Faculty of Engineering, Hokkaido University, North-13, West-8, Kita-ku, Sapporo, Hokkaido, 060-8628, Japan.
| | - Shaoyu Ye
- Department of Environmental Engineering, Faculty of Engineering, Hokkaido University, North-13, West-8, Kita-ku, Sapporo, Hokkaido, 060-8628, Japan
| | - Xi Lan
- Department of Environmental Engineering, Faculty of Engineering, Hokkaido University, North-13, West-8, Kita-ku, Sapporo, Hokkaido, 060-8628, Japan
| | - Keishi Nukada
- Department of Environmental Engineering, Faculty of Engineering, Hokkaido University, North-13, West-8, Kita-ku, Sapporo, Hokkaido, 060-8628, Japan
| | - Haozhe Zhang
- Department of Environmental Engineering, Faculty of Engineering, Hokkaido University, North-13, West-8, Kita-ku, Sapporo, Hokkaido, 060-8628, Japan
| | - Kanae Kobayashi
- Department of Environmental Engineering, Faculty of Engineering, Hokkaido University, North-13, West-8, Kita-ku, Sapporo, Hokkaido, 060-8628, Japan
- Super-cutting-edge Grand and Advanced Research (SUGAR) Program, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, Kanagawa, 237-0061, Japan
| | - Mamoru Oshiki
- Department of Environmental Engineering, Faculty of Engineering, Hokkaido University, North-13, West-8, Kita-ku, Sapporo, Hokkaido, 060-8628, Japan
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8
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Paunkov A, Hummel K, Strasser D, Sóki J, Leitsch D. Proteomic analysis of metronidazole resistance in the human facultative pathogen Bacteroides fragilis. Front Microbiol 2023; 14:1158086. [PMID: 37065137 PMCID: PMC10102347 DOI: 10.3389/fmicb.2023.1158086] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 03/14/2023] [Indexed: 04/03/2023] Open
Abstract
The anaerobic gut bacteria and opportunistic pathogen Bacteroides fragilis can cause life-threatening infections when leaving its niche and reaching body sites outside of the gut. The antimicrobial metronidazole is a mainstay in the treatment of anaerobic infections and also highly effective against Bacteroides spp. Although resistance rates have remained low in general, metronidazole resistance does occur in B. fragilis and can favor fatal disease outcomes. Most metronidazole-resistant Bacteroides isolates harbor nim genes, commonly believed to encode for nitroreductases which deactivate metronidazole. Recent research, however, suggests that the mode of resistance mediated by Nim proteins might be more complex than anticipated because they affect the cellular metabolism, e.g., by increasing the activity of pyruvate:ferredoxin oxidoreductase (PFOR). Moreover, although nim genes confer only low-level metronidazole resistance to Bacteroides, high-level resistance can be much easier induced in the laboratory in the presence of a nim gene than without. Due to these observations, we hypothesized that nim genes might induce changes in the B. fragilis proteome and performed comparative mass-spectrometric analyses with B. fragilis 638R, either with or without the nimA gene. Further, we compared protein expression profiles in both strains after induction of high-level metronidazole resistance. Interestingly, only few proteins were repeatedly found to be differentially expressed in strain 638R with the nimA gene, one of them being the flavodiiron protein FprA, an enzyme involved in oxygen scavenging. After induction of metronidazole resistance, a far higher number of proteins were found to be differentially expressed in 638R without nimA than in 638R with nimA. In the former, factors for the import of hemin were strongly downregulated, indicating impaired iron import, whereas in the latter, the observed changes were not only less numerous but also less specific. Both resistant strains, however, displayed a reduced capability of scavenging oxygen. Susceptibility to metronidazole could be widely restored in resistant 638R without nimA by supplementing growth media with ferrous iron sulfate, but not so in resistant 638R with the nimA gene. Finally, based on the results of this study, we present a novel hypothetic model of metronidazole resistance and NimA function.
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Affiliation(s)
- Ana Paunkov
- Institute for Specific Prophylaxis and Tropical Medicine, Center for Pathophysiology, Infectiology, and Immunology, Medical University of Vienna, Vienna, Austria
| | - Karin Hummel
- VetCore Facility for Research, University of Veterinary Medicine, Vienna, Austria
| | - Doris Strasser
- Institute for Specific Prophylaxis and Tropical Medicine, Center for Pathophysiology, Infectiology, and Immunology, Medical University of Vienna, Vienna, Austria
| | - József Sóki
- Faculty of Medicine, Institute of Medical Microbiology, University of Szeged, Szeged, Hungary
| | - David Leitsch
- Institute for Specific Prophylaxis and Tropical Medicine, Center for Pathophysiology, Infectiology, and Immunology, Medical University of Vienna, Vienna, Austria
- *Correspondence: David Leitsch,
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9
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Meslé MM, Gray CR, Dlakić M, DuBois JL. Bacteroides thetaiotaomicron, a Model Gastrointestinal Tract Species, Prefers Heme as an Iron Source, Yields Protoporphyrin IX as a Product, and Acts as a Heme Reservoir. Microbiol Spectr 2023; 11:e0481522. [PMID: 36862015 PMCID: PMC10100974 DOI: 10.1128/spectrum.04815-22] [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: 12/07/2022] [Accepted: 02/03/2023] [Indexed: 03/03/2023] Open
Abstract
Members of the phylum Bacteroidetes are abundant in healthy gastrointestinal (GI) tract flora. Bacteroides thetaiotaomicron is a commensal heme auxotroph and representative of this group. Bacteroidetes are sensitive to host dietary iron restriction but proliferate in heme-rich environments that are also associated with colon cancer. We hypothesized that B. thetaiotaomicron may act as a host reservoir for iron and/or heme. In this study, we defined growth-promoting quantities of iron for B. thetaiotaomicron. B. thetaiotaomicron preferentially consumed and hyperaccumulated iron in the form of heme when presented both heme and nonheme iron sources in excess of its growth needs, leading to an estimated 3.6 to 8.4 mg iron in a model GI tract microbiome consisting solely of B. thetaiotaomicron. Protoporphyrin IX was identified as an organic coproduct of heme metabolism, consistent with anaerobic removal of iron from the heme leaving the intact tetrapyrrole as the observed product. Notably, no predicted or discernible pathway for protoporphyrin IX generation exists in B. thetaiotaomicron. Heme metabolism in congeners of B. thetaiotaomicron has previously been associated with the 6-gene hmu operon, based on genetic studies. A bioinformatics survey demonstrated that the intact operon is widespread in but confined to members of the Bacteroidetes phylum and ubiquitous in healthy human GI tract flora. Anaerobic heme metabolism by commensal Bacteroidetes via hmu is likely a major contributor to human host metabolism of the heme from dietary red meat and a driver for the selective growth of these species in the GI tract consortium. IMPORTANCE Research on bacterial iron metabolism has historically focused on the host-pathogen relationship, where the host suppresses pathogen growth by cutting off access to iron. Less is known about how host iron is shared with bacterial species that live commensally in the anaerobic human GI tract, typified by members of phylum Bacteroidetes. While many facultative pathogens avidly produce and consume heme iron, most GI tract anaerobes are heme auxotrophs whose metabolic preferences we aimed to describe. Understanding iron metabolism by model microbiome species like Bacteroides thetaiotaomicron is essential for modeling the ecology of the GI tract, which serves the long-term biomedical goals of manipulating the microbiome to facilitate host metabolism of iron and remediate dysbiosis and associated pathologies (e.g., inflammation and cancer).
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Affiliation(s)
- Margaux M. Meslé
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, USA
| | - Chase R. Gray
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, USA
| | - Mensur Dlakić
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, Montana, USA
| | - Jennifer L. DuBois
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, USA
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10
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Ryan D, Bornet E, Prezza G, Alampalli SV, de Carvalho TF, Felchle H, Ebbecke T, Hayward R, Deutschbauer AM, Barquist L, Westermann AJ. An integrated transcriptomics-functional genomics approach reveals a small RNA that modulates Bacteroides thetaiotaomicron sensitivity to tetracyclines. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.16.528795. [PMID: 36824877 PMCID: PMC9949090 DOI: 10.1101/2023.02.16.528795] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Gene expression plasticity allows bacteria to adapt to diverse environments, tie their metabolism to available nutrients, and cope with stress. This is particularly relevant in a niche as dynamic and hostile as the human intestinal tract, yet transcriptional networks remain largely unknown in gut Bacteroides spp. Here, we map transcriptional units and profile their expression levels in Bacteroides thetaiotaomicron over a suite of 15 defined experimental conditions that are relevant in vivo , such as variation of temperature, pH, and oxygen tension, exposure to antibiotic stress, and growth on simple carbohydrates or on host mucin-derived glycans. Thereby, we infer stress- and carbon source-specific transcriptional regulons, including conditional expression of capsular polysaccharides and polysaccharide utilization loci, and expand the annotation of small regulatory RNAs (sRNAs) in this organism. Integrating this comprehensive expression atlas with transposon mutant fitness data, we identify conditionally important sRNAs. One example is MasB, whose inactivation led to increased bacterial tolerance of tetracyclines. Using MS2 affinity purification coupled with RNA sequencing, we predict targets of this sRNA and discuss their potential role in the context of the MasB-associated phenotype. Together, this transcriptomic compendium in combination with functional sRNA genomics-publicly available through a new iteration of the 'Theta-Base' web browser (www.helmholtz-hiri.de/en/datasets/bacteroides-v2)-constitutes a valuable resource for the microbiome and sRNA research communities alike.
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11
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Butler NL, Ito T, Foreman S, Morgan JE, Zagorevsky D, Malamy MH, Comstock LE, Barquera B. Bacteroides fragilis Maintains Concurrent Capability for Anaerobic and Nanaerobic Respiration. J Bacteriol 2023; 205:e0038922. [PMID: 36475831 PMCID: PMC9879120 DOI: 10.1128/jb.00389-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Accepted: 11/02/2022] [Indexed: 12/13/2022] Open
Abstract
Bacteroides species can use fumarate and oxygen as terminal electron acceptors during cellular respiration. In the human gut, oxygen diffuses from intestinal epithelial cells supplying "nanaerobic" oxygen levels. Many components of the anaerobic respiratory pathway have been determined, but such analyses have not been performed for nanaerobic respiration. Here, we present genetic, biochemical, enzymatic, and mass spectrometry analyses to elucidate the nanaerobic respiratory pathway in Bacteroides fragilis. Under anaerobic conditions, the transfer of electrons from NADH to the quinone pool has been shown to be contributed by two enzymes, NQR and NDH2. We find that the activity contributed by each under nanaerobic conditions is 77 and 23%, respectively, similar to the activity levels under anaerobic conditions. Using mass spectrometry, we show that the quinone pool also does not differ under these two conditions and consists of a mixture of menaquinone-8 to menaquinone-11, with menaquinone-10 predominant under both conditions. Analysis of fumarate reductase showed that it is synthesized and active under anaerobic and nanaerobic conditions. Previous RNA sequencing data and new transcription reporter assays show that expression of the cytochrome bd oxidase gene does not change under these conditions. Under nanaerobic conditions, we find both increased CydA protein and increased cytochrome bd activity. Reduced-minus-oxidized spectra of membranes showed the presence of heme d when the bacteria were grown in the presence of protoporphyrin IX and iron under both anaerobic and nanaerobic conditions, suggesting that the active oxidase can be assembled with or without oxygen. IMPORTANCE By performing a comprehensive analysis of nanaerobic respiration in Bacteroides fragilis, we show that this organism maintains capabilities for anaerobic respiration on fumarate and nanaerobic respiration on oxygen simultaneously. The contribution of the two NADH:quinone oxidoreductases and the composition of the quinone pool are the same under both conditions. Fumarate reductase and cytochrome bd are both present, and which of these terminal enzymes is active in electron transfer depends on the availability of the final electron acceptor: fumarate or oxygen. The synthesis of cytochrome bd and fumarate reductase under both conditions serves as an adaptation to an environment with low oxygen concentrations so that the bacteria can maximize energy conservation during fluctuating environmental conditions or occupation of different spatial niches.
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Affiliation(s)
- Nicole L. Butler
- Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, New York, USA
| | - Takeshi Ito
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York, USA
| | - Sara Foreman
- Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, New York, USA
| | - Joel E. Morgan
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York, USA
| | - Dmitry Zagorevsky
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York, USA
| | - Michael H. Malamy
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Laurie E. Comstock
- Duchossois Family Institute and Department of Microbiology, University of Chicago, Chicago, Illinois, USA
| | - Blanca Barquera
- Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, New York, USA
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York, USA
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, New York, USA
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12
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Alsuhaibani MN, Aljuraiban GS, Aljazairy EA, Abudawood M, Hussain SD, Alnaami A, Sabico S, Al-Daghri NM, Al-Musharaf S. Dietary Polyphenols in Relation to Gut Microbiota Composition in Saudi Arabian Females. Metabolites 2022; 13:metabo13010006. [PMID: 36676929 PMCID: PMC9864957 DOI: 10.3390/metabo13010006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 12/11/2022] [Accepted: 12/16/2022] [Indexed: 12/24/2022] Open
Abstract
Polyphenols may modulate gut microbiota; however, limited studies have examined this relationship relative to obesity. We aim to investigate the association between polyphenol intake and gut microbiota composition in relation to obesity indices among Saudi Arabian females. This study included 92 adults stratified by body mass index (BMI) into controls (BMI ≥ 18.5−24.9 kg/m2; n = 48) and cases (BMI ≥ 30.0 kg/m2; n = 44), and further divided into high and low polyphenol intake by median intake (252 mg/1000 kcal/day). Fecal samples were collected to analyze the gut microbiota composition via the whole-genome shotgun sequencing technique. Results showed that Flavonifractor plautii and Clostridium bolteae were positively correlated with polyphenol intake in the total sample (r = 0.22, p = 0.03; r = 0.28, p = 0.01, respectively). There were inverse correlations between Blautia wexlerae and polyphenol intake (r = −0.56, p < 0.01) in the case group, and between Bacteroides thetaiotaomicron and polyphenol intake (r = −0.45, p = 0.03) in the control group. Those in the case group with low polyphenol intake, and those with high waist-to-hip ratio (WHR; ≥0.83), showed significantly lower alpha-diversity than those in the control group with normal WHR (<0.83), (p < 0.05). Findings suggest that polyphenols are correlated with specific bacteria and may play an important role in the modulation of gut microbiota and obesity management.
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Affiliation(s)
- Munirah N. Alsuhaibani
- Department of Community Health Sciences, College of Applied Medical Sciences, King Saud University, Riyadh 11451, Saudi Arabia
| | - Ghadeer S. Aljuraiban
- Department of Community Health Sciences, College of Applied Medical Sciences, King Saud University, Riyadh 11451, Saudi Arabia
| | - Esra’a A. Aljazairy
- Department of Community Health Sciences, College of Applied Medical Sciences, King Saud University, Riyadh 11451, Saudi Arabia
| | - Manal Abudawood
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, King Saud University, Riyadh 11433, Saudi Arabia
| | - Syed D. Hussain
- Chair for Biomarkers of Chronic Diseases, Riyadh Biochemistry Department, College of Science, King Saud University, Riyadh 11451, Saudi Arabia
| | - Abdullah Alnaami
- Chair for Biomarkers of Chronic Diseases, Riyadh Biochemistry Department, College of Science, King Saud University, Riyadh 11451, Saudi Arabia
| | - Shaun Sabico
- Chair for Biomarkers of Chronic Diseases, Riyadh Biochemistry Department, College of Science, King Saud University, Riyadh 11451, Saudi Arabia
| | - Nasser M. Al-Daghri
- Chair for Biomarkers of Chronic Diseases, Riyadh Biochemistry Department, College of Science, King Saud University, Riyadh 11451, Saudi Arabia
| | - Sara Al-Musharaf
- Department of Community Health Sciences, College of Applied Medical Sciences, King Saud University, Riyadh 11451, Saudi Arabia
- Correspondence:
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13
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Bahadur A, Li T, Sajjad W, Nasir F, Zia MA, Wu M, Zhang G, Liu G, Chen T, Zhang W. Transcriptional and biochemical analyses of Planomicrobium strain AX6 from Qinghai-Tibetan Plateau, China, reveal hydrogen peroxide scavenging potential. BMC Microbiol 2022; 22:265. [PMID: 36335290 PMCID: PMC9636757 DOI: 10.1186/s12866-022-02677-w] [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: 03/15/2022] [Accepted: 10/17/2022] [Indexed: 11/06/2022] Open
Abstract
Background The bacterial mechanisms responsible for hydrogen peroxide (H2O2) scavenging have been well-reported, yet little is known about how bacteria isolated from cold-environments respond to H2O2 stress. Therefore, we investigated the transcriptional profiling of the Planomicrobium strain AX6 strain isolated from the cold-desert ecosystem in the Qaidam Basin, Qinghai-Tibet Plateau, China, in response to H2O2 stress aiming to uncover the molecular mechanisms associated with H2O2 scavenging potential. Methods We investigated the H2O2-scavenging potential of the bacterial Planomicrobium strain AX6 isolated from the cold-desert ecosystem in the Qaidam Basin, Qinghai-Tibet Plateau, China. Furthermore, we used high-throughput RNA-sequencing to unravel the molecular aspects associated with the H2O2 scavenging potential of the Planomicrobium strain AX6 isolate. Results In total, 3,427 differentially expressed genes (DEGs) were identified in Planomicrobium strain AX6 isolate in response to 4 h of H2O2 (1.5 mM) exposure. Besides, Kyoto Encyclopedia of Genes and Genomes pathway and Gene Ontology analyses revealed the down- and/or up-regulated pathways following H2O2 treatment. Our study not only identified the H2O2 scavenging capability of the strain nevertheless also a range of mechanisms to cope with the toxic effect of H2O2 through genes involved in oxidative stress response. Compared to control, several genes coding for antioxidant proteins, including glutathione peroxidase (GSH-Px), Coproporphyrinogen III oxidase, and superoxide dismutase (SOD), were relatively up-regulated in Planomicrobium strain AX6, when exposed to H2O2. Conclusions Overall, the results suggest that the up-regulated genes responsible for antioxidant defense pathways serve as essential regulatory mechanisms for removing H2O2 in Planomicrobium strain AX6. The DEGs identified here could provide a competitive advantage for the existence of Planomicrobium strain AX6 in H2O2-polluted environments. Supplementary Information The online version contains supplementary material available at 10.1186/s12866-022-02677-w.
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14
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Yang G, Lin A, Wu X, Lin C, Zhu S, Zhuang L. Geobacter-associated prophages confer beneficial effect on dissimilatory reduction of Fe(III) oxides. FUNDAMENTAL RESEARCH 2022. [DOI: 10.1016/j.fmre.2022.10.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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15
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Li J, Ran X, Zhou M, Wang K, Wang H, Wang Y. Oxidative stress and antioxidant mechanisms of obligate anaerobes involved in biological waste treatment processes: A review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 838:156454. [PMID: 35667421 DOI: 10.1016/j.scitotenv.2022.156454] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 05/23/2022] [Accepted: 05/31/2022] [Indexed: 06/15/2023]
Abstract
In-depth understanding of the molecular mechanisms and physiological consequences of oxidative stress is still limited for anaerobes. Anaerobic biotechnology has become widely accepted by the wastewater/sludge industry as a better alternative to more conventional but costly aerobic processes. However, the functional anaerobic microorganisms used in anaerobic biotechnology are frequently hampered by reactive oxygen/nitrogen species (ROS/RNS)-mediated oxidative stress caused by exposure to stressful factors (e.g., oxygen and heavy metals), which negatively impact treatment performance. Thus, identifying stressful factors and understanding antioxidative defense mechanisms of functional obligate anaerobes are crucial for the optimization of anaerobic bioprocesses. Herein, we present a comprehensive overview of oxidative stress and antioxidant mechanisms of obligate anaerobes involved in anaerobic bioprocesses; as examples, we focus on anaerobic ammonium oxidation bacteria and methanogenic archaea. We summarize the primary stress factors in anaerobic bioprocesses and the cellular antioxidant defense systems of functional anaerobes, a consortia of enzymatic and nonenzymatic mechanisms. The dual role of ROS/RNS in cellular processes is elaborated; at low concentrations, they have vital cell signaling functions, but at high concentrations, they cause oxidative damage. Finally, we highlight gaps in knowledge and future work to uncover antioxidant and damage repair mechanisms in obligate anaerobes. This review provides in-depth insights and guidance for future research on oxidative stress of obligate anaerobes to boost the accurate regulation of anaerobic bioprocesses in challenging and changing operating conditions.
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Affiliation(s)
- Jia Li
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, Tongji University, Shanghai 200092, China
| | - Xiaochuan Ran
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, Tongji University, Shanghai 200092, China
| | - Mingda Zhou
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, Tongji University, Shanghai 200092, China
| | - Kaichong Wang
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, Tongji University, Shanghai 200092, China
| | - Han Wang
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, Tongji University, Shanghai 200092, China.
| | - Yayi Wang
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, Tongji University, Shanghai 200092, China
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16
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Mazenc A, Mervant L, Maslo C, Lencina C, Bézirard V, Levêque M, Ahn I, Alquier-Bacquié V, Naud N, Héliès-Toussaint C, Debrauwer L, Chevolleau S, Guéraud F, Pierre FHF, Théodorou V, Olier M. Maternal heme-enriched diet promotes a gut pro-oxidative status associated with microbiota alteration, gut leakiness and glucose intolerance in mice offspring. Redox Biol 2022; 53:102333. [PMID: 35588638 PMCID: PMC9119830 DOI: 10.1016/j.redox.2022.102333] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 05/06/2022] [Accepted: 05/06/2022] [Indexed: 12/17/2022] Open
Abstract
Maternal environment, including nutrition and microbiota, plays a critical role in determining offspring's risk of chronic diseases such as diabetes later in life. Heme iron requirement is amplified during pregnancy and lactation, while excessive dietary heme iron intake, compared to non-heme iron, has shown to trigger acute oxidative stress in the gut resulting from reactive aldehyde formation in conjunction with microbiota reshape. Given the immaturity of the antioxidant defense system in early life, we investigated the extent to which a maternal diet enriched with heme iron may have a lasting impact on gut homeostasis and glucose metabolism in 60-day-old C3H/HeN mice offspring. As hypothesized, the form of iron added to the maternal diet differentially governed the offspring's microbiota establishment despite identical fecal iron status in the offspring. Importantly, despite female offspring was unaffected, oxidative stress markers were however higher in the gut of male offspring from heme enriched-fed mothers, and were accompanied by increases in fecal lipocalin-2, intestinal para-cellular permeability and TNF-α expression. In addition, male mice displayed blood glucose intolerance resulting from impaired insulin secretion following oral glucose challenge. Using an integrated approach including an aldehydomic analysis, this male-specific phenotype was further characterized and revealed close covariations between unidentified putative reactive aldehydes and bacterial communities belonging to Bacteroidales and Lachnospirales orders. Our work highlights how the form of dietary iron in the maternal diet can dictate the oxidative status in gut offspring in a sex-dependent manner, and how a gut microbiota-driven oxidative challenge in early life can be associated with gut barrier defects and glucose metabolism disorders that may be predictive of diabetes development. Maternal heminic vs. non-heminic iron intake differentially and persistently imprints the offspring's fecal microbiota. Males from heme-fed dams exhibit increased gut lumen reactive aldehydes in absence of direct dietary exposure to heme iron. Some of the increased reactive aldehydes closely covariated with Orders belonging to Bacteroidales and Lachnospirales. Maternal exposure to dietary heme iron impairs gut barrier and glucose tolerance in male offspring.
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Affiliation(s)
- Anaïs Mazenc
- Toxalim (Research Centre in Food Toxicology), INRAE, Université de Toulouse, ENVT, INP-Purpan, UPS, Toulouse, France
| | - Loïc Mervant
- Toxalim (Research Centre in Food Toxicology), INRAE, Université de Toulouse, ENVT, INP-Purpan, UPS, Toulouse, France; Metatoul-AXIOM Plaform, National Infrastructure for Metabolomics and Fluxomics, MetaboHUB, Toulouse, France
| | - Claire Maslo
- Toxalim (Research Centre in Food Toxicology), INRAE, Université de Toulouse, ENVT, INP-Purpan, UPS, Toulouse, France
| | - Corinne Lencina
- Toxalim (Research Centre in Food Toxicology), INRAE, Université de Toulouse, ENVT, INP-Purpan, UPS, Toulouse, France
| | - Valérie Bézirard
- Toxalim (Research Centre in Food Toxicology), INRAE, Université de Toulouse, ENVT, INP-Purpan, UPS, Toulouse, France
| | - Mathilde Levêque
- Toxalim (Research Centre in Food Toxicology), INRAE, Université de Toulouse, ENVT, INP-Purpan, UPS, Toulouse, France
| | - Ingrid Ahn
- Toxalim (Research Centre in Food Toxicology), INRAE, Université de Toulouse, ENVT, INP-Purpan, UPS, Toulouse, France
| | - Valérie Alquier-Bacquié
- Toxalim (Research Centre in Food Toxicology), INRAE, Université de Toulouse, ENVT, INP-Purpan, UPS, Toulouse, France
| | - Nathalie Naud
- Toxalim (Research Centre in Food Toxicology), INRAE, Université de Toulouse, ENVT, INP-Purpan, UPS, Toulouse, France
| | - Cécile Héliès-Toussaint
- Toxalim (Research Centre in Food Toxicology), INRAE, Université de Toulouse, ENVT, INP-Purpan, UPS, Toulouse, France
| | - Laurent Debrauwer
- Toxalim (Research Centre in Food Toxicology), INRAE, Université de Toulouse, ENVT, INP-Purpan, UPS, Toulouse, France; Metatoul-AXIOM Plaform, National Infrastructure for Metabolomics and Fluxomics, MetaboHUB, Toulouse, France
| | - Sylvie Chevolleau
- Toxalim (Research Centre in Food Toxicology), INRAE, Université de Toulouse, ENVT, INP-Purpan, UPS, Toulouse, France; Metatoul-AXIOM Plaform, National Infrastructure for Metabolomics and Fluxomics, MetaboHUB, Toulouse, France
| | - Françoise Guéraud
- Toxalim (Research Centre in Food Toxicology), INRAE, Université de Toulouse, ENVT, INP-Purpan, UPS, Toulouse, France
| | - Fabrice H F Pierre
- Toxalim (Research Centre in Food Toxicology), INRAE, Université de Toulouse, ENVT, INP-Purpan, UPS, Toulouse, France
| | - Vassilia Théodorou
- Toxalim (Research Centre in Food Toxicology), INRAE, Université de Toulouse, ENVT, INP-Purpan, UPS, Toulouse, France
| | - Maïwenn Olier
- Toxalim (Research Centre in Food Toxicology), INRAE, Université de Toulouse, ENVT, INP-Purpan, UPS, Toulouse, France.
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17
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Lin L, Zou M, Lu Z. The aerobic electron flux is deficient in fumarate respiration of a strict anaerobe Bacteroides thetaiotaomicron. Biochem Biophys Res Commun 2022; 614:213-218. [PMID: 35623108 DOI: 10.1016/j.bbrc.2022.05.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 05/05/2022] [Indexed: 11/28/2022]
Abstract
Why oxygen ceases the growth of strictly anaerobic bacteria is a longstanding question, yet the answer remains unclear. Studies have confirmed that the dehydratase-fumarase containing an iron-sulfur cluster ([4Fe-4S]) is inactivated upon exposure to oxygen in the intestinal obligate anaerobe, Bacteroides thetaiotaomicron (B. thetaiotaomicron); this blocks fumarate respiration, which is the essential energy-producing pathway in anaerobes. Here, we substituted the [4Fe-4S]-dependent fumarase in B. thetaiotaomicron with an iron-free isozyme from E. coli (Ec-FumC). Results show that Ec-FumC successfully performed the catalytic function of fumarase in B. thetaiotaomicron, as the fum-mutant strain that expressed Ec-FumC exhibited succinate-producing ability under anaerobic growth conditions. Ec-FumC is oxygen-resistant and remains active to produce fumarate upon aeration; however, B. thetaiotaomicron mutant that expressed Ec-FumC did not convert fumarate to succinate during air exposure. Biochemical assays of inverted membrane vesicles from wild-type B. thetaiotaomicron confirmed that the electron flux from NADH to fumarate was less efficient in the presence of air as compared to that without oxygen. Our findings suggest that the anaerobic fumarate respiration might be paralyzed due to electron dissipations upon aeration of the obligate anaerobe.
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Affiliation(s)
- Luyou Lin
- Department of Biology, Guangdong Provincial Key Laboratory of Marine Biotechnology, Institute of Marine Sciences, Shantou University, Shantou, 515063, China
| | - Meng Zou
- Department of Biology, Guangdong Provincial Key Laboratory of Marine Biotechnology, Institute of Marine Sciences, Shantou University, Shantou, 515063, China
| | - Zheng Lu
- Department of Biology, Guangdong Provincial Key Laboratory of Marine Biotechnology, Institute of Marine Sciences, Shantou University, Shantou, 515063, China.
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18
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Paunkov A, Gutenbrunner K, Sóki J, Leitsch D. Haemin deprivation renders Bacteroides fragilis hypersusceptible to metronidazole and cancels high-level metronidazole resistance. J Antimicrob Chemother 2022; 77:1027-1031. [PMID: 35040989 PMCID: PMC8969417 DOI: 10.1093/jac/dkab485] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Accepted: 12/07/2021] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Infections with Bacteroides fragilis are routinely treated with metronidazole, a 5-nitroimidazole antibiotic that is active against most anaerobic microorganisms. Metronidazole has remained a reliable treatment option, but resistance does occur, including in B. fragilis. OBJECTIVES In this study we tested whether haemin, a growth supplement for B. fragilis in vivo and in vitro, had an influence on the susceptibility of resistant B. fragilis strains to metronidazole. We further tested whether haemin-deprived B. fragilis would be more susceptible to oxygen and oxidative stress. Metronidazole has been described to cause oxidative stress, which we argued would be exacerbated in haemin-deprived B. fragilis because the bacteria harness haemin, and the iron released from it, in antioxidant enzymes such as catalase and superoxide dismutase. METHODS Haemin was omitted from growth media and the effect on metronidazole susceptibility was monitored in susceptible and resistant B. fragilis strains. Further, haemin-deprived B. fragilis were tested for resistance to aeration and hydrogen peroxide and the capacity for the removal of oxygen. RESULTS Omission of haemin from the growth medium rendered metronidazole-resistant B. fragilis strains, including an MDR isolate from the UK, highly susceptible to metronidazole. Haemin deprivation further rendered B. fragilis highly susceptible to oxygen, which was further exacerbated in resistant strains. B. fragilis was incapable of scavenging oxygen when haemin was omitted. CONCLUSIONS We propose that haemin deprivation overrules resistance mechanisms by rendering B. fragilis hypersusceptible to metronidazole due to a compromised antioxidant defence. Monitoring of haemin concentrations is imperative when conducting metronidazole susceptibility testing in B. fragilis.
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Affiliation(s)
- Ana Paunkov
- Institute for Specific Prophylaxis and Tropical Medicine Center for Pathophysiology, Infectiology, and Immunology, Medical University of Vienna, Kinderspitalgasse 15, A-1090 Vienna, Austria
| | - Katrin Gutenbrunner
- Institute for Specific Prophylaxis and Tropical Medicine Center for Pathophysiology, Infectiology, and Immunology, Medical University of Vienna, Kinderspitalgasse 15, A-1090 Vienna, Austria
| | - József Sóki
- Institute of Medical Microbiology, Faculty of Medicine, University of Szeged, Semmelweis 6, H-6725 Szeged, Hungary
| | - David Leitsch
- Institute for Specific Prophylaxis and Tropical Medicine Center for Pathophysiology, Infectiology, and Immunology, Medical University of Vienna, Kinderspitalgasse 15, A-1090 Vienna, Austria
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19
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When anaerobes encounter oxygen: mechanisms of oxygen toxicity, tolerance and defence. Nat Rev Microbiol 2021; 19:774-785. [PMID: 34183820 PMCID: PMC9191689 DOI: 10.1038/s41579-021-00583-y] [Citation(s) in RCA: 84] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/19/2021] [Indexed: 02/06/2023]
Abstract
The defining trait of obligate anaerobes is that oxygen blocks their growth, yet the underlying mechanisms are unclear. A popular hypothesis was that these microorganisms failed to evolve defences to protect themselves from reactive oxygen species (ROS) such as superoxide and hydrogen peroxide, and that this failure is what prevents their expansion to oxic habitats. However, studies reveal that anaerobes actually wield most of the same defences that aerobes possess, and many of them have the capacity to tolerate substantial levels of oxygen. Therefore, to understand the structures and real-world dynamics of microbial communities, investigators have examined how anaerobes such as Bacteroides, Desulfovibrio, Pyrococcus and Clostridium spp. struggle and cope with oxygen. The hypoxic environments in which these organisms dwell - including the mammalian gut, sulfur vents and deep sediments - experience episodic oxygenation. In this Review, we explore the molecular mechanisms by which oxygen impairs anaerobes and the degree to which bacteria protect their metabolic pathways from it. The emergent view of anaerobiosis is that optimal strategies of anaerobic metabolism depend upon radical chemistry and low-potential metal centres. Such catalytic sites are intrinsically vulnerable to direct poisoning by molecular oxygen and ROS. Observations suggest that anaerobes have evolved tactics that either minimize the extent to which oxygen disrupts their metabolism or restore function shortly after the stress has dissipated.
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20
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Distribution of Sulfate-Reducing Bacteria in the Environment: Cryopreservation Techniques and Their Potential Storage Application. Processes (Basel) 2021. [DOI: 10.3390/pr9101843] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Sulfate-reducing bacteria (SRB) are a heterogeneous group of anaerobic microorganisms that play an important role in producing hydrogen sulfide not only in the natural environment, but also in the gastrointestinal tract and oral cavity of animals and humans. The present review was written with the inclusion of 110 references including the time period from 1951 to 2021. The following databases were evaluated: Web of Science, Scopus and Google Scholar. The articles chosen to be included in the review were written mainly in the English and Czech languages. The molecular mechanisms of microbial cryoprotection differ depending on the environment where microorganisms were initially isolated. It was observed that the viability of microorganisms after cryopreservation is dependent on a number of factors, primarily colony age, amount of inoculum, cell size or rate of cooling, and their molecular inventory. Therefore, this paper is devoted to assessing the performance and suitability of various cryopreservation methods of intestinal bacteria, including molecular mechanisms of their protection. In order to successfully complete the cryopreservation process, selecting the correct laboratory equipment and cryopreservation methodology is important. Our analysis revealed that SRB should be stored in glass vials to help mitigate the corrosive nature of hydrogen sulfide, which can affect their physiology on a molecular level. Furthermore, it is recommended that their storage be performed in distilled water or in a suspension with a low salt concentration. From a molecular biological and bioengineering perspective, this contribution emphasizes the need to consider the potential impact associated with SRB in the medical, construction, and environmental sectors.
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Haran JP, Zeamer A, Ward DV, Dutta P, Bucci V, McCormick BA. The Nursing Home Older Adult Gut Microbiome Composition Shows Time-dependent Dysbiosis and Is Influenced by Medication Exposures, Age, Environment, and Frailty. J Gerontol A Biol Sci Med Sci 2021; 76:1930-1938. [PMID: 34125200 PMCID: PMC8514073 DOI: 10.1093/gerona/glab167] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Indexed: 12/30/2022] Open
Abstract
Older adults in nursing homes (NHs) have increased frailty, medication, and antimicrobial exposures, all factors that are known to affect the composition of gut microbiota. Our objective was to define which factors have the greatest association with the NH resident gut microbiota, explore patterns of dysbiosis and compositional changes in gut microbiota over time in this environment. We collected serial stool samples from NH residents. Residents were assessed using the Mini Nutritional Assessment tool and Clinical Frailty Scale. Bacterial composition of resident stool samples was determined by metagenomic sequencing. We used mixed-effect random forest modeling to identify clinical covariates that associate with microbiota. We enrolled and followed 166 residents from 5 NHs collecting 512 stool samples and following 15 residents for > 1 year. Medications, particularly psychoactive and antihypertensive medications, had the greatest effect on the microbiota. Age and frailty also contributed, and were associated with increased and decreased diversity, respectively. The microbiota of residents who had lived in the NH for > 1 year were enriched in inflammatory and pathogenic species and reduced in anti-inflammatory and symbiotic species. We observed intraindividual stability of the microbiome among older adults who had lived in the NH already for >1 year followed with sample collections 1 year apart. Older adult NH gut microbiome is heavily influenced by medications, age, and frailty. This microbiome is influenced by the length of NH residency with dysbiosis becoming evident at 12 months, however, after this point there is demonstrated relative stability over time.
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Affiliation(s)
- John P Haran
- Department of Emergency Medicine, University of Massachusetts Medical School, Worcester, USA
- Program in Microbiome Dynamics, University of Massachusetts Medical School, Worcester, USA
| | - Abigail Zeamer
- Program in Microbiome Dynamics, University of Massachusetts Medical School, Worcester, USA
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, USA
| | - Doyle V Ward
- Program in Microbiome Dynamics, University of Massachusetts Medical School, Worcester, USA
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, USA
| | - Protiva Dutta
- Department of Emergency Medicine, University of Massachusetts Medical School, Worcester, USA
| | - Vanni Bucci
- Program in Microbiome Dynamics, University of Massachusetts Medical School, Worcester, USA
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, USA
| | - Beth A McCormick
- Program in Microbiome Dynamics, University of Massachusetts Medical School, Worcester, USA
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, USA
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22
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Abstract
When attempting to propagate infections, bacterial pathogens encounter phagocytes that encase them in vacuoles called phagosomes. Within phagosomes, bacteria are bombarded with a plethora of stresses that often lead to their demise. However, pathogens have evolved numerous strategies to counter those host defenses and facilitate survival. Given the importance of phagosome-bacteria interactions to infection outcomes, they represent a collection of targets that are of interest for next-generation antibacterials. To facilitate such therapies, different approaches can be employed to increase understanding of phagosome-bacteria interactions, and these can be classified broadly as top down (starting from intact systems and breaking down the importance of different parts) or bottom up (developing a knowledge base on simplified systems and progressively increasing complexity). Here we review knowledge of phagosomal compositions and bacterial survival tactics useful for bottom-up approaches, which are particularly relevant for the application of reaction engineering to quantify and predict the time evolution of biochemical species in these death-dealing vacuoles. Further, we highlight how understanding in this area can be built up through the combination of immunology, microbiology, and engineering.
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Affiliation(s)
- Darshan M Sivaloganathan
- Program in Quantitative and Computational Biology, Princeton University, Princeton, New Jersey 08544, USA
| | - Mark P Brynildsen
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, USA;
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23
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Do Primocolonizing Bacteria Enable Bacteroides thetaiotaomicron Intestinal Colonization Independently of the Capacity To Consume Oxygen? mSphere 2021; 6:6/3/e00232-19. [PMID: 33952662 PMCID: PMC8103986 DOI: 10.1128/msphere.00232-19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Aerobic bacteria are frequent primocolonizers of the human naive intestine. Their generally accepted role is to eliminate oxygen, which would allow colonization by anaerobes that subsequently dominate bacterial gut populations. Aerobic bacteria are frequent primocolonizers of the human naive intestine. Their generally accepted role is to eliminate oxygen, which would allow colonization by anaerobes that subsequently dominate bacterial gut populations. In this hypothesis-based study, we revisited this dogma experimentally in a germfree mouse model as a mimic of the germfree newborn. We varied conditions leading to the establishment of the dominant intestinal anaerobe Bacteroides thetaiotaomicron. Two variables were introduced: Bacteroides inoculum size and preestablishment by bacteria capable or not of consuming oxygen. High Bacteroides inoculum size enabled its primocolonization. At low inocula, we show that bacterial preestablishment was decisive for subsequent Bacteroides colonization. However, even non-oxygen-respiring bacteria, a hemAEscherichia coli mutant and the intestinal obligate anaerobe Clostridium scindens, facilitated Bacteroides establishment. These findings, which are supported by recent reports, revise the long-held assumption that oxygen scavenging is the main role for aerobic primocolonizing bacteria. Instead, we suggest that better survival of aerobic bacteria ex vivo during vectorization between hosts could be a reason for their frequent primocolonization.
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24
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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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25
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Wu ZC, Wu L, Zhang M, Zhou W. Genome sequence and annotation of Bacteroides sp aff. Thetaiotaomicron strain isolated from blood. INFECTION GENETICS AND EVOLUTION 2021; 91:104816. [PMID: 33771725 DOI: 10.1016/j.meegid.2021.104816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 01/13/2021] [Accepted: 03/21/2021] [Indexed: 11/27/2022]
Abstract
This study is focused on genome sequence and annotation of the Bacteroides strain isolated from the blood of a patient with descending colon cancer. According to a comparison of the 16S ribosomal RNA sequence with the National Center for Biotechnology Information database, this strain was identified as Bacteroides sp. aff. Thetaiotaomicron. The next-generation sequencing of the strain was performed in a GENEWIZ laboratory (Jiangsu, China) on Illumina HiSeq device. According to CAZy classification, metabolic pathways related to carbohydrate metabolism of this strain engage the following enzymes: 427 glycosylhydrolases, 277 glycosyltransferases, 137 carbohydrate-binding modules, 48 carbohydrate esterases, and 24 polysaccharide lyases. According to the KEGG pathway database, Bacteroides sp. aff thetaiotaomicron strain is reported to incorporate 199 pathway associated genes. Bacteroides sp. aff. Thetaiotaomicron exposes the capacity of metabolizing a variety of polysaccharides. Its genome is enriched with an expanded repertoire of enzymes for the hydrolysis of glycosidic bonds and, thus, likely to hydrolyze most of glycosidic bonds in biological polysaccharides. The advanced capabilities of the studied strain to recognize and respond to environmental signals are expressed in the rich representation of one- and two-component signal transduction systems.
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Affiliation(s)
- Zhi Cheng Wu
- Clinical Laboratory, The First Affiliated Hospital of Hainan Medical University, 31 Longhua Road, Haikou, Hainan Province 570102, China.
| | - Lin Wu
- School of Tropical and Laboratory Medicine, Hainan Medical University, 31 Longhua Road, Haikou City, Hainan Province 571199, China; Faculty of Biotechnology and Biotechnics, National Technical University of Ukraine, Kyiv, Ukraine; Key Laboratory of Tropical Translational Medicine, Ministry of Education, Hainan Medical University, Haikou City, Hainan Province, China.
| | - Meng Zhang
- Sanya People's Hospital, Jiefang Third Road, 558, Sanya City, Hainan Province 572000, China
| | - WeiLan Zhou
- Clinical Laboratory, The First Affiliated Hospital of Hainan Medical University, 31 Longhua Road, Haikou, Hainan Province 570102, China
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26
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Insertional Inactivation of Prevotella intermedia OxyR Results in Reduced Survival with Oxidative Stress and in the Presence of Host Cells. Microorganisms 2021; 9:microorganisms9030551. [PMID: 33800047 PMCID: PMC7999485 DOI: 10.3390/microorganisms9030551] [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: 02/06/2021] [Revised: 02/25/2021] [Accepted: 02/27/2021] [Indexed: 11/17/2022] Open
Abstract
One of the most abundant bacteria in the subgingival pockets of patients with bleeding following mechanical periodontal therapy is Prevotella intermedia. However, despite its abundance, the molecular mechanisms of its contribution to periodontal disease are not well known. This is mainly due to the lack of genetic tools that would allow examination of the role of predicted virulence factors in the pathogenesis of this bacterium. Here, we report on the first mutant in the P. intermedia OMA14 strain. The mutation is an allelic exchange replacement of the sequences coding for a putative OxyR regulator with ermF sequences coding for the macrolide-lincosamide resistance in anaerobic bacteria. The mutant is severely impaired in its ability to grow with eukaryotic cells, indicating that it is an important target for interventional strategies. Further analyses reveal that its ability to grow with oxidative stress species, in the form of hydrogen peroxide and oxygen, is severely affected. Transcriptome analysis reveals that the major deregulated genes code for the alkylhydroperoxide reductase system, AhpCF, mediating protection from peroxide stress. Moreover, genes coding for Dps, CydA and Ftn are downregulated in the mutant strain, as further verified using qRT-PCR analysis. In conclusion, we succeeded in generating the first P. intermedia mutant and show that the OxyR-deficient strain is unable to survive with a variety of host cells as well as with oxidative stress.
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27
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Liu H, Shiver AL, Price MN, Carlson HK, Trotter VV, Chen Y, Escalante V, Ray J, Hern KE, Petzold CJ, Turnbaugh PJ, Huang KC, Arkin AP, Deutschbauer AM. Functional genetics of human gut commensal Bacteroides thetaiotaomicron reveals metabolic requirements for growth across environments. Cell Rep 2021; 34:108789. [PMID: 33657378 PMCID: PMC8121099 DOI: 10.1016/j.celrep.2021.108789] [Citation(s) in RCA: 68] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 11/30/2020] [Accepted: 02/03/2021] [Indexed: 12/12/2022] Open
Abstract
Harnessing the microbiota for beneficial outcomes is limited by our poor understanding of the constituent bacteria, as the functions of most of their genes are unknown. Here, we measure the growth of a barcoded transposon mutant library of the gut commensal Bacteroides thetaiotaomicron on 48 carbon sources, in the presence of 56 stress-inducing compounds, and during mono-colonization of gnotobiotic mice. We identify 516 genes with a specific phenotype under only one or a few conditions, enabling informed predictions of gene function. For example, we identify a glycoside hydrolase important for growth on type I rhamnogalacturonan, a DUF4861 protein for glycosaminoglycan utilization, a 3-keto-glucoside hydrolase for disaccharide utilization, and a tripartite multidrug resistance system specifically for bile salt tolerance. Furthermore, we show that B. thetaiotaomicron uses alternative enzymes for synthesizing nitrogen-containing metabolic precursors based on ammonium availability and that these enzymes are used differentially in vivo in a diet-dependent manner.
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Affiliation(s)
- Hualan Liu
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Anthony L Shiver
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Morgan N Price
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Hans K Carlson
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Valentine V Trotter
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Yan Chen
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Veronica Escalante
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Jayashree Ray
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Kelsey E Hern
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Christopher J Petzold
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Peter J Turnbaugh
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94143, USA; Chan Zuckerberg Biohub, San Francisco, CA 94158, USA
| | - Kerwyn Casey Huang
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA; Chan Zuckerberg Biohub, San Francisco, CA 94158, USA; Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Adam P Arkin
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; Department of Bioengineering, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Adam M Deutschbauer
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA 94720, USA.
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28
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Yan Y, Wang W, Wu M, Jetten MSM, Guo J, Ma J, Wang H, Dai X, Wang Y. Transcriptomics Uncovers the Response of Anammox Bacteria to Dissolved Oxygen Inhibition and the Subsequent Recovery Mechanism. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:14674-14685. [PMID: 33147001 DOI: 10.1021/acs.est.0c02842] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Understanding the recovery of anaerobic ammonium-oxidizing (anammox) bacteria after inhibition by dissolved oxygen (DO) is critical for the successful applications of anammox-based processes. Therefore, the effects of oxygen exposure (2 mg L-1 DO for 90 min) and subsequent recovery treatments [N2 purging or nano zero-valent iron (nZVI) addition] on the activity and gene expression in a Kuenenia stuttgartiensis enrichment culture were examined. Combining the self-organizing map clustering and enrichment analysis, we proposed the oxidative stress response of anammox bacteria based on the existing concepts of oxidative stress in microbes: the DO exposure triggered a stringent response in K. stuttgartiensis, which downregulated the transcription levels of genes involved in the central metabolism and diverted energy to a flagellar assembly and metal transport modules; these changes possibly promoted survival during the inhibition of anammox activity. According to the cotranscription with central catabolism genes, putative reactive oxygen species (ROS) scavenger genes (kat and sod) were presumed to detoxify the anammox intermediates rather than ROS. In addition, both activity and mRNA profiles with appropriate amount of nZVI addition (5 and 25 mg L-1) were close to that of control, which proved the effectiveness of nZVI addition in anammox recovery. These results would be relevant to the physio-biochemistry development of anammox bacteria and further enhancement of nitrogen removal in wastewater treatment.
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Affiliation(s)
- Yuan Yan
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Siping Road, Shanghai 200092, P. R. China
| | - Weigang Wang
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Siping Road, Shanghai 200092, P. R. China
| | - Mengxiong Wu
- Advanced Water Management Centre (AWMC), The University of Queensland, St. Lucia, Brisbane, Queensland 4072, Australia
| | - Mike S M Jetten
- Microbiology, IWWR, Faculty of Science, Radboud University Nijmegen, Heyendaalseweg 135, AJ Nijmegen 6525, The Netherlands
| | - Jianhua Guo
- Advanced Water Management Centre (AWMC), The University of Queensland, St. Lucia, Brisbane, Queensland 4072, Australia
| | - Jie Ma
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Siping Road, Shanghai 200092, P. R. China
| | - Han Wang
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Siping Road, Shanghai 200092, P. R. China
| | - Xiaohu Dai
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Siping Road, Shanghai 200092, P. R. China
| | - Yayi Wang
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Siping Road, Shanghai 200092, P. R. China
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29
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Janßen D, Dworschak L, Ludwig C, Ehrmann MA, Vogel RF. Interspecies assertiveness of Lactobacillus curvatus and Lactobacillus sakei in sausage fermentations. Int J Food Microbiol 2020; 331:108689. [PMID: 32623291 DOI: 10.1016/j.ijfoodmicro.2020.108689] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 05/18/2020] [Accepted: 05/24/2020] [Indexed: 12/25/2022]
Abstract
Lactobacillus (L.) curvatus and L. sakei contain strains, which are assertive in sausage fermentation. Previous work has demonstrated differences in assertiveness at strain level within one species, and revealed either exclusion of competitors by complementary partner strains or their inhibition by single strains. This work addresses interspecies differences in the assertiveness of L. curvatus and L. sakei. Strain sets of L. curvatus and L. sakei were employed as starters in a fermented sausage model and their abundancy upon fermentation was determined by strain-specific MALDI-TOF MS identification. Generally, single or groups of L. sakei strains outcompeted L. curvatus strains. In multiple growth tests employing mMRS and mMSM it could be shown that assertive L. sakei strains can be predicted along their μ max in mMSM. Still, L. curvatus TMW 1.624 could suppress all L. curvatus and most L. sakei strains in competitive settings. This could be referred to its expression of several bacteriocins, which are active against all of the L. curvatus strains. Strain specific differences could be demonstrated in the susceptibility of L. sakei to bacteriocins, and in oxidative stress tolerance, which is higher in co-existing L. sakei strains than in the bacteriocin producer. This suggests that tolerance to bacteriocins and oxidative stress represent additional determinants for assertiveness, above previously reported bacteriocin production versus metabolic complementarism of partner strains.
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Affiliation(s)
- Dorothee Janßen
- Technische Universität München, Lehrstuhl für Technische Mikrobiologie, Freising, Germany
| | - Lena Dworschak
- Technische Universität München, Lehrstuhl für Technische Mikrobiologie, Freising, Germany
| | - Christina Ludwig
- Bayerisches Zentrum für biomolekulare Massenspektrometrie (BayBioMS), Technische Universität München, Freising, Germany
| | - Matthias A Ehrmann
- Technische Universität München, Lehrstuhl für Technische Mikrobiologie, Freising, Germany
| | - Rudi F Vogel
- Technische Universität München, Lehrstuhl für Technische Mikrobiologie, Freising, Germany.
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30
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Zhang J, Huang YJ, Yoon JY, Kemmitt J, Wright C, Schneider K, Sphabmixay P, Hernandez-Gordillo V, Holcomb SJ, Bhushan B, Rohatgi G, Benton K, Carpenter D, Kester JC, Eng G, Breault DT, Yilmaz O, Taketani M, Voigt CA, Carrier RL, Trumper DL, Griffith LG. Primary human colonic mucosal barrier crosstalk with super oxygen-sensitive Faecalibacterium prausnitzii in continuous culture. MED 2020; 2:74-98.e9. [PMID: 33511375 DOI: 10.1016/j.medj.2020.07.001] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Background The gut microbiome plays an important role in human health and disease. Gnotobiotic animal and in vitro cell-based models provide some informative insights into mechanistic crosstalk. However, there is no existing system for a long-term co-culture of a human colonic mucosal barrier with super oxygen-sensitive commensal microbes, hindering the study of human-microbe interactions in a controlled manner. Methods Here, we investigated the effects of an abundant super oxygen-sensitive commensal anaerobe, Faecalibacterium prausnitzii, on a primary human mucosal barrier using a Gut-MIcrobiome (GuMI) physiome platform that we designed and fabricated. Findings Long-term continuous co-culture of F. prausnitzii for two days with colon epithelia, enabled by continuous flow of completely anoxic apical media and aerobic basal media, resulted in a strictly anaerobic apical environment fostering growth of and butyrate production by F. prausnitzii, while maintaining a stable colon epithelial barrier. We identified elevated differentiation and hypoxia-responsive genes and pathways in the platform compared with conventional aerobic static culture of the colon epithelia, attributable to a combination of anaerobic environment and continuous medium replenishment. Furthermore, we demonstrated anti-inflammatory effects of F. prausnitzii through HDAC and the TLR-NFKB axis. Finally, we identified that butyrate largely contributes to the anti-inflammatory effects by downregulating TLR3 and TLR4. Conclusions Our results are consistent with some clinical observations regarding F. prausnitzii, thus motivating further studies employing this platform with more complex engineered colon tissues for understanding the interaction between the human colonic mucosal barrier and microbiota, pathogens, or engineered bacteria.
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Affiliation(s)
| | | | - Jun Young Yoon
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.,School of Mechanical Engineering, Yonsei University, Seoul 03722, South Korea
| | | | | | | | | | | | | | - Brij Bhushan
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Gar Rohatgi
- EPAM Continuum, 41 University Drive, Newtown, PA 18940, USA
| | - Kyle Benton
- EPAM Continuum, 41 University Drive, Newtown, PA 18940, USA
| | | | | | | | - David T Breault
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | | | | | | | - Rebecca L Carrier
- Department of Chemical Engineering, Northeastern University, Boston, MA, USA
| | - David L Trumper
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Linda G Griffith
- Department of Biological Engineering.,Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.,Center for Gynepathology Research, Massachusetts Institute of Technology, Cambridge, MA, USA
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31
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Khazaei T, Williams RL, Bogatyrev SR, Doyle JC, Henry CS, Ismagilov RF. Metabolic multistability and hysteresis in a model aerobe-anaerobe microbiome community. SCIENCE ADVANCES 2020; 6:eaba0353. [PMID: 32851161 PMCID: PMC7423363 DOI: 10.1126/sciadv.aba0353] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 06/26/2020] [Indexed: 05/20/2023]
Abstract
Major changes in the microbiome are associated with health and disease. Some microbiome states persist despite seemingly unfavorable conditions, such as the proliferation of aerobe-anaerobe communities in oxygen-exposed environments in wound infections or small intestinal bacterial overgrowth. Mechanisms underlying transitions into and persistence of these states remain unclear. Using two microbial taxa relevant to the human microbiome, we combine genome-scale mathematical modeling, bioreactor experiments, transcriptomics, and dynamical systems theory to show that multistability and hysteresis (MSH) is a mechanism describing the shift from an aerobe-dominated state to a resilient, paradoxically persistent aerobe-anaerobe state. We examine the impact of changing oxygen and nutrient regimes and identify changes in metabolism and gene expression that lead to MSH and associated multi-stable states. In such systems, conceptual causation-correlation connections break and MSH must be used for analysis. Using MSH to analyze microbiome dynamics will improve our conceptual understanding of stability of microbiome states and transitions between states.
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Affiliation(s)
- Tahmineh Khazaei
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Rory L. Williams
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Said R. Bogatyrev
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - John C. Doyle
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
- Division of Engineering and Applied Science, California Institute of Technology, Pasadena, CA, USA
| | - Christopher S. Henry
- Data Science and Learning Division, Argonne National Laboratory, Lemont, IL, USA
| | - Rustem F. Ismagilov
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA
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32
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A high-resolution transcriptome map identifies small RNA regulation of metabolism in the gut microbe Bacteroides thetaiotaomicron. Nat Commun 2020; 11:3557. [PMID: 32678091 PMCID: PMC7366714 DOI: 10.1038/s41467-020-17348-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 06/23/2020] [Indexed: 12/15/2022] Open
Abstract
Bacteria of the genus Bacteroides are common members of the human intestinal microbiota and important degraders of polysaccharides in the gut. Among them, the species Bacteroides thetaiotaomicron has emerged as the model organism for functional microbiota research. Here, we use differential RNA sequencing (dRNA-seq) to generate a single-nucleotide resolution transcriptome map of B. thetaiotaomicron grown under defined laboratory conditions. An online browser, called ‘Theta-Base’ (www.helmholtz-hiri.de/en/datasets/bacteroides), is launched to interrogate the obtained gene expression data and annotations of ~4500 transcription start sites, untranslated regions, operon structures, and 269 noncoding RNA elements. Among the latter is GibS, a conserved, 145 nt-long small RNA that is highly expressed in the presence of N-acetyl-D-glucosamine as sole carbon source. We use computational predictions and experimental data to determine the secondary structure of GibS and identify its target genes. Our results indicate that sensing of N-acetyl-D-glucosamine induces GibS expression, which in turn modifies the transcript levels of metabolic enzymes. Bacteroides thetaiotaomicron is a human gut microbe and an emergent model organism. Here, Ryan et al. generate single-nucleotide resolution RNA-seq data for this bacterium and map transcription start sites and noncoding RNAs, one of which modulates expression of metabolic enzymes.
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Zheng Y, Fang Z, Xue Y, Zhang J, Zhu J, Gao R, Yao S, Ye Y, Wang S, Lin C, Chen S, Huang H, Hu L, Jiang GN, Qin H, Zhang P, Chen J, Ji H. Specific gut microbiome signature predicts the early-stage lung cancer. Gut Microbes 2020; 11:1030-1042. [PMID: 32240032 PMCID: PMC7524275 DOI: 10.1080/19490976.2020.1737487] [Citation(s) in RCA: 127] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Alterations of gut microbiota have been implicated in multiple diseases including cancer. However, the gut microbiota spectrum in lung cancer remains largely unknown. Here we profiled the gut microbiota composition in a discovery cohort containing 42 early-stage lung cancer patients and 65 healthy individuals through the 16S ribosomal RNA (rRNA) gene sequencing analysis. We found that lung cancer patients displayed a significant shift of microbiota composition in contrast to the healthy populations. To identify the optimal microbiota signature for noninvasive diagnosis purpose, we took advantage of Support-Vector Machine (SVM) and found that the predictive model with 13 operational taxonomic unit (OTU)-based biomarkers achieved a high accuracy in lung cancer prediction (area under curve, AUC = 97.6%). This signature performed reasonably well in the validation cohort (AUC = 76.4%), which contained 34 lung cancer patients and 40 healthy individuals. To facilitate potential clinical practice, we further constructed a 'patient discrimination index' (PDI), which largely retained the prediction efficiency in both the discovery cohort (AUC = 92.4%) and the validation cohort (AUC = 67.7%). Together, our study uncovered the microbiota spectrum of lung cancer patients and established the specific gut microbial signature for the potential prediction of the early-stage lung cancer.
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Affiliation(s)
- Yajuan Zheng
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Zhaoyuan Fang
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Yun Xue
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Jian Zhang
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Junjie Zhu
- Department of Thoracic Surgery, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Renyuan Gao
- Department of General Surgery, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
| | - Shun Yao
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Yi Ye
- School of Life Science and Technology, Shanghai Tech University, Shanghai, China
| | - Shihui Wang
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Changdong Lin
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Shiyang Chen
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Hsinyi Huang
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Liang Hu
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Ge-Ning Jiang
- Department of Thoracic Surgery, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Huanlong Qin
- Department of General Surgery, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
| | - Peng Zhang
- Department of Thoracic Surgery, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China,Peng Zhang Department of Thoracic Surgery, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai200433, China
| | - Jianfeng Chen
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China,CONTACT Hongbin Ji ; JianFeng Chen Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 320 YueYang Road, Shanghai200031, China
| | - Hongbin Ji
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China,School of Life Science and Technology, Shanghai Tech University, Shanghai, China
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Jones KR, Belvin BR, Macrina FL, Lewis JP. Sequence and characterization of shuttle vectors for molecular cloning in Porphyromonas, Bacteroides and related bacteria. Mol Oral Microbiol 2020; 35:181-191. [PMID: 32592236 DOI: 10.1111/omi.12304] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 06/19/2020] [Accepted: 06/19/2020] [Indexed: 11/28/2022]
Abstract
There is a lack of shuttle vectors to be needed for investigations into the genetics of Porphyromonas gingivalis and related species. To better understand the prevalence of candidates for such tools, we have examined multiple strains of black-pigmented anaerobes (clinical and laboratory isolates) for plasmids. As no plasmids were found in P. gingivalis strains, we have used the pYH420 plasmid, derived from P. asaccharolytica, as backbone to construct a shuttle vector in combination with pUC19 from Escherichia coli. Nucleotide sequence determination of the pYH420 plasmid revealed that it contained a gene with similarity to rep from plasmid pTS1 (isolated from Treponema denticola) as well as a homolog of mobA, a member of a gene family found on mobilizable genetic elements found in the genus Bacteroides. We constructed the pG106 and pG108 shuttle vectors using parts of the pUC19 and pYH420 vectors. This resulted in a vector with a multiple cloning site (MCS) in the lacZ gene enabling us to perform blue-white colony selection. The pG106 and pG108 shuttle vectors are electro-transformable into E. coli, P. gingivalis and B. thetaiotaomicron, where they are stable. We demonstrated that these vectors were suitable in these species for applications of molecular cloning including complementation and gene expression studies. Using the pG108 vector, we complement the hcpR mutant strain of P. gingivalis and rescued its NO 2 - -sensitive phenotype. We also performed a gene expression study using the P-glow BS2 fluorescent reporter gene and the ahpC promoter in B. thetaiotaomicron.
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Affiliation(s)
- Kevin R Jones
- The Philips Institute for Oral Health Research, Virginia Commonwealth University, Richmond, VA, USA
| | - Benjamin Ross Belvin
- The Philips Institute for Oral Health Research, Virginia Commonwealth University, Richmond, VA, USA
| | - Francis L Macrina
- The Philips Institute for Oral Health Research, Virginia Commonwealth University, Richmond, VA, USA.,Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, VA, USA
| | - Janina P Lewis
- The Philips Institute for Oral Health Research, Virginia Commonwealth University, Richmond, VA, USA.,Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, VA, USA.,Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA, USA
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Role of Superoxide Reductase FA796 in Oxidative Stress Resistance in Filifactor alocis. Sci Rep 2020; 10:9178. [PMID: 32513978 PMCID: PMC7280497 DOI: 10.1038/s41598-020-65806-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 05/07/2020] [Indexed: 12/20/2022] Open
Abstract
Filifactor alocis, a Gram-positive anaerobic bacterium, is now a proposed diagnostic indicator of periodontal disease. Because the stress response of this bacterium to the oxidative environment of the periodontal pocket may impact its pathogenicity, an understanding of its oxidative stress resistance strategy is vital. Interrogation of the F. alocis genome identified the HMPREF0389_00796 gene that encodes for a putative superoxide reductase (SOR) enzyme. SORs are non-heme, iron-containing enzymes that can catalyze the reduction of superoxide radicals to hydrogen peroxide and are important in the protection against oxidative stress. In this study, we have functionally characterized the putative SOR (FA796) from F. alocis ATCC 35896. The recombinant FA796 protein, which is predicted to be a homotetramer of the 1Fe-SOR class, can reduce superoxide radicals. F. alocis FLL141 (∆FA796::ermF) was significantly more sensitive to oxygen/air exposure compared to the parent strain. Sensitivity correlated with the level of intracellular superoxide radicals. Additionally, the FA796-defective mutant had increased sensitivity to hydrogen peroxide-induced stress, was inhibited in its ability to form biofilm and had reduced survival in epithelial cells. Collectively, these results suggest that the F. alocis SOR protein is a key enzymatic scavenger of superoxide radicals and protects the bacterium from oxidative stress conditions.
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Khademian M, Imlay JA. Do reactive oxygen species or does oxygen itself confer obligate anaerobiosis? The case of Bacteroides thetaiotaomicron. Mol Microbiol 2020; 114:333-347. [PMID: 32301184 DOI: 10.1111/mmi.14516] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 04/07/2020] [Accepted: 04/07/2020] [Indexed: 02/06/2023]
Abstract
Bacteroides thetaiotaomicron was examined to determine whether its obligate anaerobiosis is imposed by endogenous reactive oxygen species or by molecular oxygen itself. Previous analyses established that aerated B. thetaiotaomicron loses some enzyme activities due to a high rate of endogenous superoxide formation. However, the present study establishes that another key step in central metabolism is poisoned by molecular oxygen itself. Pyruvate dissimilation was shown to depend upon two enzymes, pyruvate:formate lyase (PFL) and pyruvate:ferredoxin oxidoreductase (PFOR), that lose activity upon aeration. PFL is a glycyl-radical enzyme whose vulnerability to oxygen is already understood. The rate of PFOR damage was unaffected by the level of superoxide or peroxide, showing that molecular oxygen itself is the culprit. The cell cannot repair PFOR, which amplifies the impact of damage. The rates of PFOR and fumarase inactivation are similar, suggesting that superoxide dismutase is calibrated so the oxygen- and superoxide-sensitive enzymes are equally sensitive to aeration. The physiological purpose of PFL and PFOR is to degrade pyruvate without disrupting the redox balance, and they do so using catalytic mechanisms that are intrinsically vulnerable to oxygen. In this way, the anaerobic excellence and oxygen sensitivity of B. thetaiotaomicron are two sides of the same coin.
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Affiliation(s)
- Maryam Khademian
- Department of Microbiology, University of Illinois, Urbana, IL, USA
| | - James A Imlay
- Department of Microbiology, University of Illinois, Urbana, IL, USA
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Seth D, Hausladen A, Stamler JS. Anaerobic Transcription by OxyR: A Novel Paradigm for Nitrosative Stress. Antioxid Redox Signal 2020; 32:803-816. [PMID: 31691575 PMCID: PMC7074925 DOI: 10.1089/ars.2019.7921] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Significance: S-nitrosylation, the post-translational modification by nitric oxide (NO) to form S-nitrosothiols (SNOs), regulates diverse aspects of cellular function, and aberrant S-nitrosylation (nitrosative stress) is implicated in disease, from neurodegeneration to cancer. Essential roles for S-nitrosylation have been demonstrated in microbes, plants, and animals; notably, bacteria have often served as model systems for elucidation of general principles. Recent Advances: Recent conceptual advances include the idea of a molecular code through which proteins sense and differentiate S-nitrosothiol (SNO) from alternative oxidative modifications, providing the basis for specificity in SNO signaling. In Escherichia coli, S-nitrosylation relies on an enzymatic cascade that regulates, and is regulated by, the transcription factor OxyR under anaerobic conditions. S-nitrosylated OxyR activates an anaerobic regulon of >100 genes that encode for enzymes that both mediate S-nitrosylation and protect against nitrosative stress. Critical Issues: Mitochondria originated from endosymbiotic bacteria and generate NO under hypoxic conditions, analogous to conditions in E. coli. Nitrosative stress in mitochondria has been implicated in Alzheimer's and Parkinson's disease, among others. Many proteins that are S-nitrosylated in mitochondria are also S-nitrosylated in E. coli. Insights into enzymatic regulation of S-nitrosylation in E. coli may inform the identification of disease-relevant regulatory machinery in mammalian systems. Future Directions: Using E. coli as a model system, in-depth analysis of the anaerobic response controlled by OxyR may lead to the identification of enzymatic mechanisms regulating S-nitrosylation in particular, and hypoxic signaling more generally, providing novel insights into analogous mechanisms in mammalian cells and within dysfunctional mitochondria that characterize neurodegenerative diseases.
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Affiliation(s)
- Divya Seth
- Institute for Transformative Molecular Medicine and Department of Medicine, Case Western Reserve University School of Medicine and University Hospitals Cleveland Medical Center, Cleveland, Ohio
| | - Alfred Hausladen
- Institute for Transformative Molecular Medicine and Department of Medicine, Case Western Reserve University School of Medicine and University Hospitals Cleveland Medical Center, Cleveland, Ohio
| | - Jonathan S Stamler
- Institute for Transformative Molecular Medicine and Department of Medicine, Case Western Reserve University School of Medicine and University Hospitals Cleveland Medical Center, Cleveland, Ohio.,Harrington Discovery Institute, University Hospitals Cleveland Medical Center, Cleveland, Ohio
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Zhang J, Wang S, Zeng Z, Qin Y, Li P. The complete genome sequence of Bifidobacterium animalis subsp. lactis 01 and its integral components of antioxidant defense system. 3 Biotech 2019; 9:352. [PMID: 31501753 DOI: 10.1007/s13205-019-1890-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Accepted: 08/27/2019] [Indexed: 12/13/2022] Open
Abstract
The strain Bifidobacterium animalis 01, isolated from centenarians, showed promising antioxidant potential in our previous studies. In this study, the genome information on strain 01 and the important antioxidant components are presented. The complete genome comprises a single circular chromosome (1,931,632 bp; 60.49% G + C content) with 1569 coding DNA sequences, 52 tRNA, and 9 rRNA operons. Based on phylogenomic analyses, strain 01 was designated as B. animalis subsp. lactis 01. The genomic analysis reveals that at least eight protein-coding genes are antioxidant-related genes. The conditions for simulating the oxidative stress have been determined. The results of quantitative reverse transcription PCR further demonstrated that the genes encoding the thioredoxin system (ahpC, ahpF, bcp, trxB, trxA, nrdH, and msrAB) and non-enzyme factors of the divalent cation transporter gene (mntH) were upregulated under the H2O2 challenge, indicating that the eight genes were effective components of the antioxidant system. The results of this study could benefit for understanding the antioxidant mechanism of B. animalis 01 and future utilization of it as a potential antioxidant agent.
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Affiliation(s)
- Jinlan Zhang
- 1Beijing Advanced Innovation Center for Food Nutrition and Human Health, Key Laboratory of Functional Dairy, College of Food Science and Nutritional Engineering, China Agricultural University, No. 17 Tsinghua East Road, HaiDian District, Beijing, 10083 China
| | - Shibo Wang
- 1Beijing Advanced Innovation Center for Food Nutrition and Human Health, Key Laboratory of Functional Dairy, College of Food Science and Nutritional Engineering, China Agricultural University, No. 17 Tsinghua East Road, HaiDian District, Beijing, 10083 China
| | - Zhu Zeng
- 2College of Biotechnology, Southwest University, No. 2 Tiansheng, Beibei District, Chongqing, 400715 China
| | - Yuxuan Qin
- 1Beijing Advanced Innovation Center for Food Nutrition and Human Health, Key Laboratory of Functional Dairy, College of Food Science and Nutritional Engineering, China Agricultural University, No. 17 Tsinghua East Road, HaiDian District, Beijing, 10083 China
| | - Pinglan Li
- 1Beijing Advanced Innovation Center for Food Nutrition and Human Health, Key Laboratory of Functional Dairy, College of Food Science and Nutritional Engineering, China Agricultural University, No. 17 Tsinghua East Road, HaiDian District, Beijing, 10083 China
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Complex Responses to Hydrogen Peroxide and Hypochlorous Acid by the Probiotic Bacterium Lactobacillus reuteri. mSystems 2019; 4:4/5/e00453-19. [PMID: 31481604 PMCID: PMC6722424 DOI: 10.1128/msystems.00453-19] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Inflammatory diseases of the gut are associated with increased intestinal oxygen concentrations and high levels of inflammatory oxidants, including hydrogen peroxide (H2O2) and hypochlorous acid (HOCl), which are antimicrobial compounds produced by the innate immune system. This contributes to dysbiotic changes in the gut microbiome, including increased populations of proinflammatory enterobacteria (Escherichia coli and related species) and decreased levels of health-associated anaerobic Firmicutes and Bacteroidetes The pathways for H2O2 and HOCl resistance in E. coli have been well studied, but little is known about how commensal and probiotic bacteria respond to inflammatory oxidants. In this work, we have characterized the transcriptomic response of the anti-inflammatory, gut-colonizing Gram-positive probiotic Lactobacillus reuteri to both H2O2 and HOCl. L. reuteri mounts distinct but overlapping responses to each of these stressors, and both gene expression and survival were strongly affected by the presence or absence of oxygen. Oxidative stress response in L. reuteri required several factors not found in enterobacteria, including the small heat shock protein Lo18, polyphosphate kinase 2, and RsiR, an L. reuteri-specific regulator of anti-inflammatory mechanisms.IMPORTANCE Reactive oxidants, including hydrogen peroxide and hypochlorous acid, are antimicrobial compounds produced by the immune system during inflammation. Little is known, however, about how many important types of bacteria present in the human microbiome respond to these oxidants, especially commensal and other health-associated species. We have now mapped the stress response to both H2O2 and HOCl in the intestinal lactic acid bacterium Lactobacillus reuteri.
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Lu Z, Imlay JA. A conserved motif liganding the [4Fe-4S] cluster in [4Fe-4S] fumarases prevents irreversible inactivation of the enzyme during hydrogen peroxide stress. Redox Biol 2019; 26:101296. [PMID: 31465957 PMCID: PMC6831887 DOI: 10.1016/j.redox.2019.101296] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Revised: 08/04/2019] [Accepted: 08/07/2019] [Indexed: 11/16/2022] Open
Abstract
Organisms have evolved two different classes of the ubiquitous enzyme fumarase: the [4Fe–4S] cluster-containing class I enzymes are oxidant-sensitive, whereas the class II enzymes are iron-free and therefore oxidant-resistant. When hydrogen peroxide (H2O2) attacks the most-studied [4Fe–4S] fumarases, only the cluster is damaged, and thus the cell can rapidly repair the enzyme. However, this study shows that when elevated levels of H2O2 oxidized the class I fumarase of the obligate anaerobe Bacteroides thetaiotaomicron (Bt-Fum), a hydroxyl-like radical species was produced that caused irreversible covalent damage to the polypeptide. Unlike the fumarase of oxygen-tolerant bacteria, Bt-Fum lacks a key cysteine residue in the typical “CXnCX2C″ motif that ligands [4Fe–4S] clusters. Consequently H2O2 can access and oxidize an iron atom other than the catalytic one in its cluster. Phylogenetic analysis showed that certain clades of bacteria may have evolved the full “CXnCX2C″ motif to shield the [4Fe–4S] cluster of fumarase. This effect was reproduced by the construction of a chimeric enzyme. These data demonstrate the irreversible oxidation of Fe–S cluster enzymes and may recapitulate evolutionary steps that occurred when microorganisms originally confronted oxidizing environments. It is also suggested that, if H2O2 is generated within the colon as a consequence of inflammation or the action of lactic acid bacteria, the inactivation of fumarase could potentially impair the central fermentation pathway of Bacteroides species and contribute to gut dysbiosis.
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Affiliation(s)
- Zheng Lu
- Department of Biology, Guangdong Provincial Key Laboratory of Marine Biotechnology, STU-UNIVPM Joint Algal Research Center, Shantou University, Shantou, 515063, China.
| | - James A Imlay
- Department of Microbiology, University of Illinois, 601 S. Goodwin Ave., Urbana, IL, 61801, USA
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Ślesak I, Kula M, Ślesak H, Miszalski Z, Strzałka K. How to define obligatory anaerobiosis? An evolutionary view on the antioxidant response system and the early stages of the evolution of life on Earth. Free Radic Biol Med 2019; 140:61-73. [PMID: 30862543 DOI: 10.1016/j.freeradbiomed.2019.03.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 03/01/2019] [Accepted: 03/05/2019] [Indexed: 10/27/2022]
Abstract
One of the former definitions of "obligate anaerobiosis" was based on three main criteria: 1) it occurs in organisms, so-called obligate anaerobes, which live in environments without oxygen (O2), 2) O2-dependent (aerobic) respiration, and 3) antioxidant enzymes are absent in obligate anaerobes. In contrast, aerobes need O2 in order to grow and develop properly. Obligate (or strict) anaerobes belong to prokaryotic microorganisms from two domains, Bacteria and Archaea. A closer look at anaerobiosis covers a wide range of microorganisms that permanently or in a time-dependent manner tolerate different concentrations of O2 in their habitats. On this basis they can be classified as obligate/facultative anaerobes, microaerophiles and nanaerobes. Paradoxically, O2 tolerance in strict anaerobes is usually, as in aerobes, associated with the activity of the antioxidant response system, which involves different antioxidant enzymes responsible for removing excess reactive oxygen species (ROS). In our opinion, the traditional definition of "obligate anaerobiosis" loses its original sense. Strict anaerobiosis should only be restricted to the occurrence of O2-independent pathways involved in energy generation. For that reason, a term better than "obligate anaerobes" would be O2/ROS tolerant anaerobes, where the role of the O2/ROS detoxification system is separated from O2-independent metabolic pathways that supply energy. Ubiquitous key antioxidant enzymes like superoxide dismutase (SOD) and superoxide reductase (SOR) in contemporary obligate anaerobes might suggest that their origin is ancient, maybe even the beginning of the evolution of life on Earth. It cannot be ruled out that c. 3.5 Gyr ago, local microquantities of O2/ROS played a role in the evolution of the last universal common ancestor (LUCA) of all modern organisms. On the basis of data in the literature, the hypothesis that LUCA could be an O2/ROS tolerant anaerobe is discussed together with the question of the abiotic sources of O2/ROS and/or the early evolution of cyanobacteria that perform oxygenic photosynthesis.
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Affiliation(s)
- Ireneusz Ślesak
- The Franciszek Górski Institute of Plant Physiology, Polish Academy of Sciences, Niezapominajek 21, 30-239, Krakow, Poland.
| | - Monika Kula
- The Franciszek Górski Institute of Plant Physiology, Polish Academy of Sciences, Niezapominajek 21, 30-239, Krakow, Poland.
| | - Halina Ślesak
- Institute of Botany, Jagiellonian University, Gronostajowa 9, 30-387, Krakow, Poland.
| | - Zbigniew Miszalski
- The Franciszek Górski Institute of Plant Physiology, Polish Academy of Sciences, Niezapominajek 21, 30-239, Krakow, Poland.
| | - Kazimierz Strzałka
- Malopolska Centre of Biotechnology, Jagiellonian University, Gronostajowa 7A, 30-387, Krakow, Poland; Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387, Krakow, Poland.
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Satoh T, Todoroki M, Kobayashi K, Niimura Y, Kawasaki S. Purified thioredoxin reductase from O 2-sensitive Bifidobacterium bifidum degrades H 2O 2 by interacting with alkyl hydroperoxide reductase. Anaerobe 2019; 57:45-54. [PMID: 30880149 DOI: 10.1016/j.anaerobe.2019.03.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 02/28/2019] [Accepted: 03/13/2019] [Indexed: 01/17/2023]
Abstract
Bifidobacterium is beneficial for host health and exhibits different O2 sensitivity levels among species or strains via unknown mechanisms. Bifidobacterium bifidum JCM1255T, a type species of Bifidobacterium, is an O2-sensitive bacterium that can grow under low-O2 (5%) conditions, and the growth of this species is inhibited under high-O2 conditions (10% ∼) with accumulation of H2O2. We previously reported that NADH or NAD(P)H oxidase-active fractions were detected during purification using microaerobically grown B. bifidum cells, and the active enzyme was purified from the NADH oxidase-active fraction. The purified enzyme was identified as b-type dihydroorotate dehydrogenase (DHODb) and characterized as a dominant H2O2 producer in B. bifidum. In this study, we performed further purification of the enzyme from the NAD(P)H oxidase-active fraction and characterized the purified enzyme as a part of the H2O2 degradation system in B. bifidum. This purified enzyme was identified as thioredoxin reductase (TrxR); the NAD(P)H oxidase activity of this enzyme was not expressed in anaerobically grown B. bifidum, and mRNA expression was induced by O2 exposure. Furthermore, the purified B. bifidum TrxR interacted with recombinant alkyl hydroperoxide reductase (rAhpC) and exhibited NAD(P)H peroxidase activity. These results suggest that TrxR responds to O2 and protects B. bifidum from oxidative stress by degrading H2O2 via the TrxR-AhpC system.
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Affiliation(s)
- Takumi Satoh
- Department of Molecular Microbiology, Tokyo University of Agriculture, Tokyo, Japan.
| | | | - Kazuya Kobayashi
- Department of Bioscience, Tokyo University of Agriculture, Tokyo, Japan
| | - Youichi Niimura
- Department of Molecular Microbiology, Tokyo University of Agriculture, Tokyo, Japan; Department of Bioscience, Tokyo University of Agriculture, Tokyo, Japan
| | - Shinji Kawasaki
- Department of Molecular Microbiology, Tokyo University of Agriculture, Tokyo, Japan; Department of Bioscience, Tokyo University of Agriculture, Tokyo, Japan
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Ferrentino R, Langone M, Andreottola G. Progress toward full scale application of the anaerobic side-stream reactor (ASSR) process. BIORESOURCE TECHNOLOGY 2019; 272:267-274. [PMID: 30359880 DOI: 10.1016/j.biortech.2018.10.028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 10/09/2018] [Accepted: 10/11/2018] [Indexed: 06/08/2023]
Abstract
In order to reduce the investment costs of the anaerobic side-stream reactor (ASSR) process coupled with an activated sludge system and promote the full scale application, the impact of 1 d anaerobic solid retention time (SRTASSR) and 100% interchange ratio (IR) has been investigated on sludge reduction, carbon and nutrient removal efficiency and microbial community, in a sequencing batch reactor (SBR)-ASSR system. The SBR-ASSR achieved good removal efficiencies in COD (91.5 ± 3.4%), ammonium nitrogen (98.8 ± 0.5%), total nitrogen (87.9 ± 4.9%) and phosphate (92.8 ± 6.7). The sludge yield of the system was 0.1648 g TSS g-1COD; 54% lower compared to a conventional activated sludge (CAS) system. Real time quantitative polymerase chain reaction (q-PCR) showed an abundance of hydrolyzing and fermentative bacteria. Comparison at class and genus level confirmed an abundance of anaerobic hydrolyzing and fermentative bacteria, denitrifying bacteria able to simultaneous perform nitrogen and phosphate removal and phosphate accumulating organisms.
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Affiliation(s)
- R Ferrentino
- Department of Civil, Environmental and Mechanical Engineering, University of Trento, Via Mesiano 77, 30123 Trento, Italy.
| | - M Langone
- Department of Civil, Environmental and Mechanical Engineering, University of Trento, Via Mesiano 77, 30123 Trento, Italy
| | - G Andreottola
- Department of Civil, Environmental and Mechanical Engineering, University of Trento, Via Mesiano 77, 30123 Trento, Italy
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44
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Imlay JA. Where in the world do bacteria experience oxidative stress? Environ Microbiol 2018; 21:521-530. [PMID: 30307099 DOI: 10.1111/1462-2920.14445] [Citation(s) in RCA: 174] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 10/02/2018] [Accepted: 10/07/2018] [Indexed: 11/26/2022]
Abstract
Reactive oxygen species - superoxide, hydrogen peroxide and hydroxyl radicals - have long been suspected of constraining bacterial growth in important microbial habitats and indeed of shaping microbial communities. Over recent decades, studies of paradigmatic organisms such as Escherichia coli, Salmonella typhimurium, Bacillus subtilis and Saccharomyces cerevisiae have pinpointed the biomolecules that oxidants can damage and the strategies by which microbes minimize their injuries. What is lacking is a good sense of the circumstances under which oxidative stress actually occurs. In this MiniReview several potential natural sources of oxidative stress are considered: endogenous ROS formation, chemical oxidation of reduced species at oxic-anoxic interfaces, H2 O2 production by lactic acid bacteria, the oxidative burst of phagocytes and the redox-cycling of secreted small molecules. While all of these phenomena can be reproduced and verified in the lab, the actual quantification of stress in natural habitats remains lacking - and, therefore, we have a fundamental hole in our understanding of the role that oxidative stress actually plays in the biosphere.
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Affiliation(s)
- James A Imlay
- Department of Microbiology, University of Illinois, 601 S. Goodwin Ave, Urbana, IL, 61801, USA
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Teixeira FL, Pauer H, Costa SB, Smith CJ, Domingues RMCP, Rocha ER, Lobo LA. Deletion of BmoR affects the expression of genes related to thiol/disulfide balance in Bacteroides fragilis. Sci Rep 2018; 8:14405. [PMID: 30258073 PMCID: PMC6158253 DOI: 10.1038/s41598-018-32880-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Accepted: 09/10/2018] [Indexed: 01/03/2023] Open
Abstract
Bacteroides fragilis, an opportunistic pathogen and commensal bacterium in the gut, is one the most aerotolerant species among strict anaerobes. However, the mechanisms that control gene regulation in response to oxidative stress are not completely understood. In this study, we show that the MarR type regulator, BmoR, regulates the expression of genes involved in the homeostasis of intracellular redox state. Transcriptome analysis showed that absence of BmoR leads to altered expression in total of 167 genes. Sixteen of these genes had a 2-fold or greater change in their expression. Most of these genes are related to LPS biosynthesis and carbohydrates metabolism, but there was a significant increase in the expression of genes related to the redox balance inside the cell. A pyridine nucleotide-disulfide oxidoreductase located directly upstream of bmoR was shown to be repressed by direct binding of BmoR to the promoter region. The expression of two other genes, coding for a thiosulphate:quinone-oxidoreductase and a thioredoxin, are indirectly affected by bmoR mutation during oxygen exposure. Phenotypic assays showed that BmoR is important to maintain the thiol/disulfide balance in the cell, confirming its relevance to B. fragilis response to oxidative stress.
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Affiliation(s)
- Felipe L Teixeira
- Departamento de Microbiologia Médica, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, NC, USA.
| | - Heidi Pauer
- Departamento de Microbiologia Médica, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, NC, USA
| | - Scarlathe B Costa
- Departamento de Microbiologia Médica, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - C Jeffrey Smith
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, NC, USA
| | - Regina M C P Domingues
- Departamento de Microbiologia Médica, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Edson R Rocha
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, NC, USA
| | - Leandro A Lobo
- Departamento de Microbiologia Médica, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
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O 2-inducible H 2O 2-forming NADPH oxidase is responsible for the hyper O 2 sensitivity of Bifidobacterium longum subsp. infantis. Sci Rep 2018; 8:10750. [PMID: 30013208 PMCID: PMC6048055 DOI: 10.1038/s41598-018-29030-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 07/04/2018] [Indexed: 01/04/2023] Open
Abstract
Bifidobacteria are beneficial anaerobes, and their O2 sensitivity levels differ among species as a function of unknown molecular mechanisms. Bifidobacterium longum subspecies infantis (B. infantis), a predominant colonizer of the gastrointestinal tract of infants, showed a hyper O2-sensitive growth profile with accompanying a production of H2O2. In this study, we characterized an NADPH oxidase as a key enzyme responsible for this microbe’s hyper O2 sensitivity. A dominant active elution peak of H2O2-forming NADPH oxidase activity was detected in the first step of column chromatography, and the purified NADPH oxidase (NPOX) was identified as a homolog of nitroreductase family proteins. The introduction of the gene encoding B. infantis NPOX (npoxA) into O2-tolerant Bifidobacterium minimum made the strain O2 sensitive and allowed it to produce H2O2. Knockout of the npoxA gene in B. infantis decreased the production of H2O2 and mitigated its B. infantis hyper O2 sensitivity. A transcript of B. infantis npoxA is induced by O2, suggesting that the aerobic production of toxic H2O2 is functionally conserved in B. infantis.
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Müller V, Chowdhury NP, Basen M. Electron Bifurcation: A Long-Hidden Energy-Coupling Mechanism. Annu Rev Microbiol 2018; 72:331-353. [PMID: 29924687 DOI: 10.1146/annurev-micro-090816-093440] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A decade ago, a novel mechanism to drive thermodynamically unfavorable redox reactions was discovered that is used in prokaryotes to drive endergonic electron transfer reactions by a direct coupling to an exergonic redox reaction in one soluble enzyme complex. This process is referred to as flavin-based electron bifurcation, or FBEB. An important function of FBEB is that it allows the generation of reduced low-potential ferredoxin (Fdred) from comparably high-potential electron donors such as NADH or molecular hydrogen (H2). Fdred is then the electron donor for anaerobic respiratory chains leading to the synthesis of ATP. In many metabolic scenarios, Fd is reduced by metabolic oxidoreductases and Fdred then drives endergonic metabolic reactions such as H2 production by the reverse, electron confurcation. FBEB is energetically more economical than ATP hydrolysis or reverse electron transport as a driving force for endergonic redox reactions; thus, it does "save" cellular ATP. It is essential for autotrophic growth at the origin of life and also allows for heterotrophic growth on certain low-energy substrates.
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Affiliation(s)
- Volker Müller
- Department of Molecular Microbiology and Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University Frankfurt/Main, 60438 Frankfurt, Germany;
| | - Nilanjan Pal Chowdhury
- Department of Molecular Microbiology and Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University Frankfurt/Main, 60438 Frankfurt, Germany;
| | - Mirko Basen
- Department of Molecular Microbiology and Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University Frankfurt/Main, 60438 Frankfurt, Germany;
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Li X, Imlay JA. Improved measurements of scant hydrogen peroxide enable experiments that define its threshold of toxicity for Escherichia coli. Free Radic Biol Med 2018; 120:217-227. [PMID: 29550333 PMCID: PMC5940505 DOI: 10.1016/j.freeradbiomed.2018.03.025] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 03/12/2018] [Accepted: 03/13/2018] [Indexed: 01/06/2023]
Abstract
Escherichia coli is a model organism that has been exploited to reveal key details of hydrogen peroxide stress: the biomolecules that H2O2 most rapidly damages and the defensive tactics that organisms use to fend it off. Much less clear is the amount of exogenous H2O2 that is sufficient to injure the bacterium and/or to trigger its stress response. To fill this gap, we need to study the behavior of cells when they are exposed to defined amounts of H2O2 on an hours-long time scale. Such experiments are difficult because bacteria rapidly consume H2O2 that is added to test cultures. Further, lab media itself can generate H2O2, and media components interfere with the quantification of H2O2 levels. In this study we describe mechanisms by which media components interfere with H2O2 determinations, and we identify simple ways to minimize and correct for this interference. Using these techniques, it was shown that standard media generate so much H2O2 that most intracellular H2O2 derives from the medium rather than from endogenous metabolism. Indeed, bacteria spread on plates must induce their stress response or else perish. Finally, two straightforward methods were used to sustain low-micromolar steady-state concentrations of H2O2. In this way we determined that > 2 μM extracellular H2O2 is sufficient to trigger the intracellular OxyR stress response, and > 5 μM begins to impair cell growth in a minimal medium. These concentrations are orders of magnitude lower than the doses that have typically been used in lab experiments. The new approaches should enable workers to study how various organisms cope with natural levels of H2O2 stress.
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Affiliation(s)
- Xin Li
- College of Food and Bioengineering, Henan University of Science and Technology, No. 263, Kaiyuan Ave., Luoyang, Henan 471023, China.
| | - James A Imlay
- Department of Microbiology, University of Illinois, 601 S. Goodwin Ave., Urbana, IL 61801, USA.
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49
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Wang L, Yan J, Wise MJ, Liu Q, Asenso J, Huang Y, Dai S, Liu Z, Du Y, Tang D. Distribution Patterns of Polyphosphate Metabolism Pathway and Its Relationships With Bacterial Durability and Virulence. Front Microbiol 2018; 9:782. [PMID: 29755430 PMCID: PMC5932413 DOI: 10.3389/fmicb.2018.00782] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 04/06/2018] [Indexed: 12/15/2022] Open
Abstract
Inorganic polyphosphate (polyP) is a linear polymer of orthophosphate residues. It is reported to be present in all life forms. Experimental studies showed that polyP plays important roles in bacterial durability and virulence. Here we investigated the relationships of polyP with bacterial durability and virulence theoretically. Bacterial lifestyle, environmental persistence, virulence factors (VFs), and species evolution are all included in the analysis. The presence of seven genes involved in polyP metabolism (ppk1, ppk2, pap, surE, gppA, ppnK, and ppgK) and 2595 core VFs were verified in 944 bacterial reference proteomes for distribution patterns via HMMER. Proteome size and VFs were compared in terms of gain and loss of polyP pathway. Literature mining and phylogenetic analysis were recruited to support the study. Our analyzes revealed that the presence of polyP metabolism is positively correlated with bacterial proteome size and the number of virulence genes. A potential relationship of polyP in bacterial lifestyle and environmental durability is suggested. Evolutionary analysis shows that polyP genes are randomly lost along the phylogenetic tree. In sum, based on our theoretical analysis, we confirmed that bacteria with polyP metabolism are associated with high environmental durability and more VFs.
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Affiliation(s)
- Liang Wang
- Department of Bioinformatics, School of Medical Informatics, Xuzhou Medical University, Xuzhou, China
| | - Jiawei Yan
- Xuzhou Infectious Diseases Hospital, Xuzhou, China
| | - Michael J Wise
- School of Computer Science and Software Engineering, University of Western Australia, Perth, WA, Australia.,The Marshall Centre for Infectious Diseases Research and Training, University of Western Australia, Perth, WA, Australia
| | - Qinghua Liu
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, School of Pharmacy, Xuzhou Medical University, Xuzhou, China
| | - James Asenso
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, School of Pharmacy, Xuzhou Medical University, Xuzhou, China
| | - Yue Huang
- Department of Bioinformatics, School of Medical Informatics, Xuzhou Medical University, Xuzhou, China
| | - Shiyun Dai
- School of Anesthesiology, Xuzhou Medical University, Xuzhou, China
| | | | - Yan Du
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, School of Pharmacy, Xuzhou Medical University, Xuzhou, China
| | - Daoquan Tang
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, School of Pharmacy, Xuzhou Medical University, Xuzhou, China.,Center for Experimental Animals, Xuzhou Medical University, Xuzhou, China
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50
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Bircher L, Geirnaert A, Hammes F, Lacroix C, Schwab C. Effect of cryopreservation and lyophilization on viability and growth of strict anaerobic human gut microbes. Microb Biotechnol 2018; 11:721-733. [PMID: 29663668 PMCID: PMC6011992 DOI: 10.1111/1751-7915.13265] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 02/22/2018] [Accepted: 03/08/2018] [Indexed: 01/22/2023] Open
Abstract
Strict anaerobic gut microbes have been suggested as ‘next‐generation probiotics’ for treating several intestinal disorders. The development of preservation techniques is of major importance for therapeutic application. This study investigated cryopreservation (−80°C) and lyophilization survival and storage stability (4°C for 3 months) of the strict anaerobic gut microbes Bacteroides thetaiotaomicron, Faecalibacterium prausnitzii, Roseburia intestinalis, Anaerostipes caccae, Eubacterium hallii and Blautia obeum. To improve preservation survival, protectants sucrose and inulin (both 5% w/v) were added for lyophilization and were also combined with glycerol (15% v/v) for cryopreservation. Bacterial fitness, evaluated by maximum growth rate and lag phase, viability and membrane integrity were determined using a standardized growth assay and by flow cytometry as markers for preservation resistance. Lyophilization was more detrimental to viability and fitness than cryopreservation, but led to better storage stability. Adding sucrose and inulin enhanced viability and the proportion of intact cells during lyophilization of all strains. Viability of protectant‐free B. thetaiotaomicron, A. caccae and F. prausnitzii was above 50% after cryopreservation and storage and increased to above 80% if protectants were present. The addition of glycerol, sucrose and inulin strongly enhanced the viability of B. obeum, E. hallii and R. intestinalis from 0.03–2% in protectant‐free cultures to 11–37%. This is the first study that quantitatively compared the effect of cryopreservation and lyophilization and the addition of selected protectants on viability and fitness of six strict anaerobic gut microbes. Our results suggest that efficiency of protectants is process‐ and species‐specific.
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Affiliation(s)
- Lea Bircher
- Laboratory of Food Biotechnology, Institute of Food, Nutrition and Health, ETH Zürich, Schmelzbergstrasse 7, 8092, Zürich, Switzerland
| | - Annelies Geirnaert
- Laboratory of Food Biotechnology, Institute of Food, Nutrition and Health, ETH Zürich, Schmelzbergstrasse 7, 8092, Zürich, Switzerland
| | | | - Christophe Lacroix
- Laboratory of Food Biotechnology, Institute of Food, Nutrition and Health, ETH Zürich, Schmelzbergstrasse 7, 8092, Zürich, Switzerland
| | - Clarissa Schwab
- Laboratory of Food Biotechnology, Institute of Food, Nutrition and Health, ETH Zürich, Schmelzbergstrasse 7, 8092, Zürich, Switzerland
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