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Mrnjavac N, Nagies FSP, Wimmer JLE, Kapust N, Knopp MR, Trost K, Modjewski L, Bremer N, Mentel M, Esposti MD, Mizrahi I, Allen JF, Martin WF. The radical impact of oxygen on prokaryotic evolution-enzyme inhibition first, uninhibited essential biosyntheses second, aerobic respiration third. FEBS Lett 2024; 598:1692-1714. [PMID: 38750628 DOI: 10.1002/1873-3468.14906] [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: 02/13/2024] [Revised: 04/12/2024] [Accepted: 04/19/2024] [Indexed: 07/15/2024]
Abstract
Molecular oxygen is a stable diradical. All O2-dependent enzymes employ a radical mechanism. Generated by cyanobacteria, O2 started accumulating on Earth 2.4 billion years ago. Its evolutionary impact is traditionally sought in respiration and energy yield. We mapped 365 O2-dependent enzymatic reactions of prokaryotes to phylogenies for the corresponding 792 protein families. The main physiological adaptations imparted by O2-dependent enzymes were not energy conservation, but novel organic substrate oxidations and O2-dependent, hence O2-tolerant, alternative pathways for O2-inhibited reactions. Oxygen-dependent enzymes evolved in ancestrally anaerobic pathways for essential cofactor biosynthesis including NAD+, pyridoxal, thiamine, ubiquinone, cobalamin, heme, and chlorophyll. These innovations allowed prokaryotes to synthesize essential cofactors in O2-containing environments, a prerequisite for the later emergence of aerobic respiratory chains.
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Affiliation(s)
- Natalia Mrnjavac
- Institute of Molecular Evolution, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, Germany
| | - Falk S P Nagies
- Institute of Molecular Evolution, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, Germany
| | - Jessica L E Wimmer
- Institute of Molecular Evolution, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, Germany
| | - Nils Kapust
- Institute of Molecular Evolution, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, Germany
| | - Michael R Knopp
- Institute of Molecular Evolution, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, Germany
| | - Katharina Trost
- Institute of Molecular Evolution, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, Germany
| | - Luca Modjewski
- Institute of Molecular Evolution, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, Germany
| | - Nico Bremer
- Institute of Molecular Evolution, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, Germany
| | - Marek Mentel
- Department of Biochemistry, Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovakia
| | | | - Itzhak Mizrahi
- Department of Life Sciences, Ben-Gurion University of the Negev and The National Institute for Biotechnology in the Negev, Be'er-Sheva, Israel
| | - John F Allen
- Research Department of Genetics, Evolution and Environment, University College London, UK
| | - William F Martin
- Institute of Molecular Evolution, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, Germany
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Detailed analysis of metabolism reveals growth-rate-promoting interactions between Anaerostipes caccae and Bacteroides spp. Anaerobe 2023; 79:102680. [PMID: 36473601 DOI: 10.1016/j.anaerobe.2022.102680] [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: 09/21/2022] [Revised: 11/30/2022] [Accepted: 12/01/2022] [Indexed: 12/12/2022]
Abstract
INTRODUCTION Human gut microbiota species which are next-generation probiotics (NGPs) candidates are of high interest as they have shown the potential to treat intestinal inflammation and other diseases. Unfortunately, these species are often not robust enough for large-scale cultivation, especially in maintaining diversity in co-culture production. OBJECTIVES In this study, we describe interactions between human gut microbiota species in the cultivation process with unique substrates. We also demonstrated that it is possible to change the species ratio in co-culture by changing the ratio of carbon sources. METHODS We screened 25 different bacterial species based on their metabolic capabilities. After evaluating unique substrate possibilities, we chose Anaerostipes caccae (A. caccae), Bacteroides thetaiotaomicron (B. thetaiotaomicron), and Bacteroides vulgatus (B. vulgatus) as subjects for further study. D-sorbitol, D-xylose, and D-galacturonic acid were selected as substrates for A. caccae, B. thetaiotaomicron, and B. vulgatus respectively. All three species were cultivated as both monocultures and in co-cultures in serial batch fermentations in an isothermal microcalorimeter. RESULTS Positive interactions were detected between the species in both co-cultures (A. caccae + B. thetaiotaomicron; A. caccae + B. vulgatus) resulting in higher heat production compared to the sum of the monocultures. The same positive cross-feeding interactions took place in larger-scale cultivation experiments. We confirmed acetate and lactate cross-feeding between A. caccae and B. thetaiotaomicron with flux balance analysis (FBA). CONCLUSION Changing the ratio of the selected carbon sources in the medium changed the species ratio accordingly. Such robustness is the basis for developing more efficient industrial co-culture processes including the production of NGPs.
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Subchronic Oral Cylindrospermopsin Exposure Alters the Host Gut Microbiome and Is Associated with Progressive Hepatic Inflammation, Stellate Cell Activation, and Mild Fibrosis in a Preclinical Study. Toxins (Basel) 2022; 14:toxins14120835. [PMID: 36548732 PMCID: PMC9785749 DOI: 10.3390/toxins14120835] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 11/20/2022] [Accepted: 11/21/2022] [Indexed: 12/02/2022] Open
Abstract
Epidemiological studies have reported a strong association between liver injury and incidences of hepatocellular carcinoma in sections of humans globally. Several preclinical studies have shown a strong link between cyanotoxin exposure and the development of nonalcoholic steatohepatitis, a precursor of hepatocellular carcinoma. Among the emerging threats from cyanotoxins, new evidence shows cylindrospermopsin release in freshwater lakes. A known hepatotoxin in higher concentrations, we examined the possible role of cylindrospermopsin in causing host gut dysbiosis and its association with liver pathology in a mouse model of toxico-pharmacokinetics and hepatic pathology. The results showed that oral exposure to cylindrospermopsin caused decreased diversity of gut bacteria phyla accompanied by an increased abundance of Clostridioides difficile and decreased abundance of probiotic flora such as Roseburia, Akkermanssia, and Bacteroides thetaiotamicron, a signature most often associated with intestinal and hepatic pathology and underlying gastrointestinal disease. The altered gut dysbiosis was also associated with increased Claudin2 protein in the intestinal lumen, a marker of gut leaching and endotoxemia. The study of liver pathology showed marked liver inflammation, the release of damage-associated molecular patterns, and activation of toll-like receptors, a hallmark of consistent and progressive liver damage. Hepatic pathology was also linked to increased Kupffer cell activation and stellate cell activation, markers of progressive liver damage often linked to the development of liver fibrosis and carcinoma. In conclusion, the present study provides additional evidence of cylindrospermopsin-linked progressive liver pathology that may be very well-linked to gut dysbiosis, though definitive evidence involving this link needs to be studied further.
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Dank A, Biel G, Abee T, Smid EJ. Microaerobic metabolism of lactate and propionate enhances vitamin B 12 production in Propionibacterium freudenreichii. Microb Cell Fact 2022; 21:225. [PMID: 36307780 DOI: 10.1186/s12934-022-01945-8] [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: 07/22/2022] [Accepted: 10/02/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Propionibacterium freudenreichii is used in biotechnological applications to produce vitamin B12. Although cultured mainly in anaerobic conditions, microaerobic conditions can greatly enhance biomass formation in P. freudenreichii. Since B12 yields may be coupled to biomass formation, microaerobic conditions show great potential for increasing B12 yields in P. freudenreichii. RESULTS Here we show biomass formation increases 2.7 times for P. freudenreichii grown in microaerobic conditions on lactate versus anaerobic conditions (1.87 g/L vs 0.70 g/L). Consumption of lactate in microaerobic conditions resulted first in production of pyruvate, propionate and acetate. When lactate was depleted, pyruvate and propionate were oxidised with a concomitant sixfold increase in the B12 titer compared to anaerobic conditions, showing potential for propionate and pyruvate as carbon sources for B12 production. Consequently, a fed-batch reactor with anaerobically precultured lactate-grown cells was fed propionate in microaerobic conditions resulting in biomass increase and production of B12. Vitamin yields increased from 0.3 [Formula: see text] B12 per mmol lactate in anaerobic conditions to 2.4 [Formula: see text] B12 per mmol lactate and 8.4 [Formula: see text] B12 per mmol propionate in microaerobic conditions. Yield per cell dry weight (CDW) increased from 41 [Formula: see text] per g CDW in anaerobic conditions on lactate to 92 [Formula: see text] per g CDW on lactate and 184 [Formula: see text] per g CDW on propionate in microaerobic conditions. CONCLUSIONS Here we have shown both B12 yield per substrate and per CDW were highest on cells oxidising propionate in microaerobic conditions, showing the potential of propionate for biotechnological production of vitamin B12 by P. freudenreichii.
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Affiliation(s)
- Alexander Dank
- Food Microbiology, Wageningen University and Research, Wageningen, The Netherlands
| | - Gabriela Biel
- Food Microbiology, Wageningen University and Research, Wageningen, The Netherlands
| | - Tjakko Abee
- Food Microbiology, Wageningen University and Research, Wageningen, The Netherlands
| | - Eddy J Smid
- Food Microbiology, Wageningen University and Research, Wageningen, The Netherlands.
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Fuertes-Perez S, Abele M, Ludwig C, Vogel RF, Hilgarth M. Impact of Modified Atmospheres on Growth and Metabolism of Meat-Spoilage Relevant Photobacterium spp. as Predicted by Comparative Proteomics. Front Microbiol 2022; 13:866629. [PMID: 35722325 PMCID: PMC9201721 DOI: 10.3389/fmicb.2022.866629] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 04/12/2022] [Indexed: 11/25/2022] Open
Abstract
Modified atmosphere packaging (MAP) is a common strategy to selectively prevent the growth of certain species of meat spoiling bacteria. This study aimed to determine the impact of high oxygen MAP (70% O2, 30% CO2, red and white meats) and oxygen-free MAP (70% N2, 30% CO2, also white meat and seafood) on preventing the growth of spoiling photobacteria on meat. Growth of Photobacterium carnosum and P. phosphoreum was monitored in a meat simulation media under different gas mixtures of nitrogen, oxygen, and carbon dioxide, and samples were taken during exponential growth for a comparative proteomic analysis. Growth under air atmosphere appears optimal, particularly for P. carnosum. Enhanced protein accumulation affected energy metabolism, respiration, oxygen consuming reactions, and lipid usage. However, all the other atmospheres show some degree of growth reduction. An increase in oxygen concentration leads to an increase in enzymes counteracting oxidative stress for both species and enhancement of heme utilization and iron-sulfur cluster assembly proteins for P. phosphoreum. Absence of oxygen appears to switch the metabolism toward fermentative pathways where either ribose (P. phosphoreum) or glycogen (P. carnosum) appear to be the preferred substrates. Additionally, it promotes the use of alternative electron donors/acceptors, mainly formate and nitrate/nitrite. Stress response is manifested as an enhanced accumulation of enzymes that is able to produce ammonia (e.g., carbonic anhydrase, hydroxylamine reductase) and regulate osmotic stress. Our results suggest that photobacteria do not sense the environmental levels of carbon dioxide, but rather adapt to their own anaerobic metabolism. The regulation in presence of carbon dioxide is limited and strain-specific under anaerobic conditions. However, when oxygen at air-like concentration (21%) is present together with carbon dioxide (30%), the oxidative stress appears enhanced compared to air conditions (very low carbon dioxide), as explained if both gases have a synergistic effect. This is further supported by the increase in oxygen concentration in the presence of carbon dioxide. The atmosphere is able to fully inhibit P. carnosum, heavily reduce P. phosphoreum growth in vitro, and trigger diversification of energy production with higher energetic cost, highlighting the importance of concomitant bacteria for their growth on raw meat under said atmosphere.
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Affiliation(s)
- Sandra Fuertes-Perez
- Lehrstuhl für Technische Mikrobiologie, Technische Universität München, Munich, Germany
| | - Miriam Abele
- Bayerisches Zentrum für Biomolekulare Massenspektrometrie (BayBioMS), Technische Universität München, Munich, Germany
| | - Christina Ludwig
- Bayerisches Zentrum für Biomolekulare Massenspektrometrie (BayBioMS), Technische Universität München, Munich, Germany
| | - Rudi F Vogel
- Lehrstuhl für Technische Mikrobiologie, Technische Universität München, Munich, Germany
| | - Maik Hilgarth
- Lehrstuhl für Technische Mikrobiologie, Technische Universität München, Munich, Germany
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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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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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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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Kim K, Choe D, Song Y, Kang M, Lee SG, Lee DH, Cho BK. Engineering Bacteroides thetaiotaomicron to produce non-native butyrate based on a genome-scale metabolic model-guided design. Metab Eng 2021; 68:174-186. [PMID: 34655791 DOI: 10.1016/j.ymben.2021.10.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Revised: 10/04/2021] [Accepted: 10/09/2021] [Indexed: 12/29/2022]
Abstract
Bacteroides thetaiotaomicron represents a major symbiont of the human gut microbiome that is increasingly viewed as a promising candidate strain for microbial therapeutics. Here, we engineer B. thetaiotaomicron for heterologous production of non-native butyrate as a proof-of-concept biochemical at therapeutically relevant concentrations. Since B. thetaiotaomicron is not a natural producer of butyrate, we heterologously expressed a butyrate biosynthetic pathway in the strain, which led to the production of butyrate at the final concentration of 12 mg/L in a rich medium. Further optimization of butyrate production was achieved by a round of metabolic engineering guided by an expanded genome-scale metabolic model (GEM) of B. thetaiotaomicron. The in silico knock-out simulation of the expanded model showed that pta and ldhD were the potent knock-out targets to enhance butyrate production. The maximum titer and specific productivity of butyrate in the pta-ldhD double knockout mutant increased by nearly 3.4 and 4.8 folds, respectively. To our knowledge, this is the first engineering attempt that enabled butyrate production from a non-butyrate producing commensal B. thetaiotaomicron. The study also highlights that B. thetaiotaomicron can serve as an effective strain for live microbial therapeutics in human.
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Affiliation(s)
- Kangsan Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Donghui Choe
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Yoseb Song
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Minjeong Kang
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Seung-Goo Lee
- Synthetic Biology & Bioengineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, 34141, Republic of Korea
| | - Dae-Hee Lee
- Synthetic Biology & Bioengineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, 34141, Republic of Korea
| | - Byung-Kwan Cho
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea; KAIST Institute for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea.
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Sun X, Sun J, Sun Y, Li C, Fang J, Zhang T, Wan Y, Xu L, Zhou Y, Wang L, Dong B. Oxygen Self‐Sufficient Nanoplatform for Enhanced and Selective Antibacterial Photodynamic Therapy against Anaerobe‐Induced Periodontal Disease. ADVANCED FUNCTIONAL MATERIALS 2021; 31:2101040. [DOI: 10.1002/adfm.202101040] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Indexed: 07/31/2023]
Affiliation(s)
- Xiaolin Sun
- Department of Oral Implantology School of Dentistry Jilin University Changchun 130021 China
| | - Jiao Sun
- Department of Cell Biology Norman Bethune College of Medicine Jilin University Changchun 130021 China
| | - Yue Sun
- Department of Oral Implantology School of Dentistry Jilin University Changchun 130021 China
| | - Chunyan Li
- Jilin Provincial Key Laboratory of Sciences and Technology for Stomatology Nanoengineering Changchun 130021 China
| | - Jiao Fang
- Department of Oral Implantology School of Dentistry Jilin University Changchun 130021 China
| | - Tianshou Zhang
- Jilin Provincial Key Laboratory of Sciences and Technology for Stomatology Nanoengineering Changchun 130021 China
| | - Yao Wan
- Department of Oral Implantology School of Dentistry Jilin University Changchun 130021 China
| | - Lin Xu
- State Key Laboratory on Integrated Optoelectronics College of Electronic Science and Engineering Jilin University Changchun 130012 China
| | - Yanmin Zhou
- Department of Oral Implantology School of Dentistry Jilin University Changchun 130021 China
| | - Lin Wang
- Department of Oral Implantology School of Dentistry Jilin University Changchun 130021 China
| | - Biao Dong
- State Key Laboratory on Integrated Optoelectronics College of Electronic Science and Engineering Jilin University Changchun 130012 China
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Yekani M, Baghi HB, Vahed SZ, Ghanbari H, Hosseinpur R, Azargun R, Azimi S, Memar MY. Tightly controlled response to oxidative stress; an important factor in the tolerance of Bacteroides fragilis. Res Microbiol 2021; 172:103798. [PMID: 33485914 DOI: 10.1016/j.resmic.2021.103798] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 01/07/2021] [Accepted: 01/08/2021] [Indexed: 12/01/2022]
Abstract
The exposure of Bacteroides fragilis to highly oxygenated tissues induces an oxidative stress due to a shift from the reduced condition of the gastrointestinal tract to an aerobic environment of host tissues. The potent and effective responses to reactive oxygen species (ROS) make the B. fragilis tolerant to atmospheric oxygen for several days. The response to oxidative stress in B. fragilis is a complicated event that is induced and regulated by different agents. In this review, we will focus on the B. fragilis response to oxidative stress and present an overview of the regulators of responses to oxidative stress in this bacterium.
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Affiliation(s)
- Mina Yekani
- Department of Microbiology, Faculty of Medicine, Kashan University of Medical Sciences, Kashan, Iran; Student Research Committee, Kashan University of Medical Sciences, Kashan, Iran
| | - Hossein Bannazadeh Baghi
- Infectious and Tropical Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | | | - Hadi Ghanbari
- Department of Pharmacognosy, Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Rasul Hosseinpur
- Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Robab Azargun
- Department of Microbiology, Faculty of Medicine, Maragheh University of Medical Sciences, Maragheh, Iran
| | - Somayeh Azimi
- Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mohammad Yousef Memar
- Infectious and Tropical Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Microbiology Department, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.
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12
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He Y, Tian Z, Yi Q, Zhang Y, Yang M. Impact of oxytetracycline on anaerobic wastewater treatment and mitigation using enhanced hydrolysis pretreatment. WATER RESEARCH 2020; 187:116408. [PMID: 32949826 DOI: 10.1016/j.watres.2020.116408] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Revised: 09/03/2020] [Accepted: 09/06/2020] [Indexed: 06/11/2023]
Abstract
In this study, two parallel-operated up-flow anaerobic sludge bed reactors, one used to treat synthetic wastewater spiked with oxytetracycline and the other used to treat the same wastewater after enhanced hydrolysis, were used to evaluate the impact of oxytetracycline on anaerobic digestion and resistance development and the efficacy of enhanced hydrolysis pretreatment on the elimination of adverse effects. The reactors were operated under a constant organic-loading rate (10 g/L/d) with increasing oxytetracycline doses (0 mg/L to 200 mg/L) over a period of 15 months. For the reactor without pretreatment, the chemical oxygen demand removal reached up to 89.5%%at oxytetracycline doses ranging from 0 mg/L to 100 mg/L, which collapsed at higher oxytetracycline doses. Miseq sequencing showed that a diverse hydrolysis/fermentation/acetogenesis bacterial community was maintained as the oxytetracycline dose was increased from 0 mg/L to 100 mg/L, while extreme dominance of Macellibacteroides (65.70%%- 71.56%) was found to occur at higher oxytetracycline doses. The total abundance of antibiotic resistance genes increased from 1.3 × 10-1 copies per cell to 2.6 × 10-1 copies per cell with increasing oxytetracycline dose from 0 mg/L to 5 mg/L, remained unchanged at oxytetracycline doses ranging from 25 mg/L to 100 mg/L, and then increased to 4.8 × 10-1 copies per cell and 1.3 copies per cell at oxytetracycline doses of 150 mg/L and 200 mg/L, respectively. Multidrug resistance developed in response to oxytetracycline treatment at 200 mg/L. Poor chemical oxygen demand removal and a marked enrichment in antibiotic resistance genes was validated using a full-scale up-flow anaerobic sludge bed system fed with an influent oxytetracycline concentration of approximately 200 mg/L. For the reactor treating wastewater pretreated with enhanced hydrolysis (85 °C for 6 h), the chemical oxygen demand removal rate and antibiotic resistance genes level over the whole oxytetracycline dose range were found to be similar to those achieved with zero oxytetracycline treatment. These results demonstrated that the control of conventional pollutants and ARGs could be achieved simultaneously in the UASB reactor by employing enhanced hydrolysis pretreatment.
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Affiliation(s)
- Yupeng He
- State Key Laboratory of Environmental Aquatic Chemistry,Research Center for Eco-Environmental Sciences, Chinese Academy of Science, Post Office Box 2871, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhe Tian
- State Key Laboratory of Environmental Aquatic Chemistry,Research Center for Eco-Environmental Sciences, Chinese Academy of Science, Post Office Box 2871, Beijing 100085, China; National Engineering Laboratory for Industrial Wastewater Treatment, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Qizhen Yi
- State Key Laboratory of Environmental Aquatic Chemistry,Research Center for Eco-Environmental Sciences, Chinese Academy of Science, Post Office Box 2871, Beijing 100085, China; National Engineering Laboratory for Industrial Wastewater Treatment, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Yu Zhang
- State Key Laboratory of Environmental Aquatic Chemistry,Research Center for Eco-Environmental Sciences, Chinese Academy of Science, Post Office Box 2871, Beijing 100085, China; National Engineering Laboratory for Industrial Wastewater Treatment, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Min Yang
- State Key Laboratory of Environmental Aquatic Chemistry,Research Center for Eco-Environmental Sciences, Chinese Academy of Science, Post Office Box 2871, Beijing 100085, China; National Engineering Laboratory for Industrial Wastewater Treatment, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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13
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Chathoth K, Martin B, Cornelis P, Yvenou S, Bonnaure-Mallet M, Baysse C. The events that may contribute to subgingival dysbiosis: a focus on the interplay between iron, sulfide and oxygen. FEMS Microbiol Lett 2020; 367:5860280. [DOI: 10.1093/femsle/fnaa100] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 06/19/2020] [Indexed: 12/21/2022] Open
Abstract
ABSTRACT
This minireview considers the disruption of the host–microbiota harmless symbiosis in the subgingival niche. The establishment of a chronic infection by subversion of a commensal microbiota results from a complex and multiparametric sequence of events. This review narrows down to the interplay between oxygen, iron and sulfide that can result in a vicious cycle that would favor peroxygenic and glutathione producing streptococci as well as sulfidogenic anaerobic pathogens in the subgingival niche. We propose hypothesis and discuss strategies for the therapeutic modulation of the microbiota to prevent periodontitis and promote oral health.
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Affiliation(s)
- Kanchana Chathoth
- NuMeCan INSERM U1241, CIMIAD, Université de Rennes 1, F-35043 Rennes, France
| | - Bénédicte Martin
- NuMeCan INSERM U1241, CIMIAD, Université de Rennes 1, F-35043 Rennes, France
| | - Pierre Cornelis
- Department of Bioengineering Sciences, Laboratory of Microbiology, Vrije Universiteit Brussel, B-1050 Brussels, Belgium
- Laboratoire de Microbiologie Signaux et Microenvironnement, LMSM EA4312, Université de Rouen Normandie, Normandie Université, F-27000 Évreux, France
| | - Stéven Yvenou
- NuMeCan INSERM U1241, CIMIAD, Université de Rennes 1, F-35043 Rennes, France
| | - Martine Bonnaure-Mallet
- NuMeCan INSERM U1241, CIMIAD, Université de Rennes 1, F-35043 Rennes, France
- CHU Pontchaillou Rennes, 35000 Rennes, France
| | - Christine Baysse
- NuMeCan INSERM U1241, CIMIAD, Université de Rennes 1, F-35043 Rennes, France
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14
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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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15
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Kolbeck S, Ludwig C, Meng C, Hilgarth M, Vogel RF. Comparative Proteomics of Meat Spoilage Bacteria Predicts Drivers for Their Coexistence on Modified Atmosphere Packaged Meat. Front Microbiol 2020; 11:209. [PMID: 32117190 PMCID: PMC7033586 DOI: 10.3389/fmicb.2020.00209] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 01/29/2020] [Indexed: 12/19/2022] Open
Abstract
Besides intrinsic and extrinsic factors such as antagonism for organic substrates or temperature, the storage atmosphere of meat has a high influence on the development of its initial microbiota. Specific modified atmospheres (MAs) selectively suppress growth of aerobic and anaerobic bacteria, thus reshaping the initial microbiota. As some microorganisms are more tolerant to MA, they overgrow competitors and produce metabolites that cause rejection of the product. In order to elucidate responses to different MA by means of metabolic adaptation and competition for organic substrates on meat, the typical representative meat spoilage bacteria Brochothrix (B.) thermosphacta TMW2.2101 and four lactic acid bacteria Carnobacterium (C.) divergens TMW2.1577, C. maltaromaticum TMW2.1581, Leuconostoc (L.) gelidum subsp. gelidum TMW2.1618 and L. gelidum subsp. gasicomitatum TMW2.1619 were chosen. Bacteria were grown in sterile glass bottles filled with a meat simulation medium, which was aerated constantly with either air, 100%_N2, 30%_CO2/70%_O2 or 30%_CO2/70%_N2. Growth of bacteria during incubation at 25°C and stirring at 120 rpm was monitored over 48 h and a label-free quantitative mass spectrometric approach was employed to determine changes within the bacterial proteomes in response to oxygen and carbon dioxide. Both Leuconostoc subsp. were intrinsically tolerant to MA, exhibiting no proteomic regulation of enzymes, whereas the other species provide a set of metabolic adaptation mechanism, enabling higher resistance to the detrimental effects of MA. Those mechanisms comprise: enhanced oxidative stress reduction, adjustment of the pyruvate metabolism and catabolic oxygen consumption in response to oxygen and intracellular pH homeostasis, maintenance of osmotic balance and alteration of the fatty acid composition in response to carbon dioxide. We further evaluated the potential of industrial used MA to inhibit specific bacterial spoilage. No bacterial inhibition is predicted for 30%_CO2/70%_O2 for the analyzed species, whereas 30%_CO2/70%_N2 predictively inhibits C. divergens TMW21577 and B. thermosphacta TMW2.2101. Furthermore, species-specific metabolic pathways enabling different and preferential carbon source utilization were identified, which enable non-competitive coexistence of respective bacteria on meat, resulting in synergistic spoilage. In conclusion, this study gives mechanistically explanations of their acknowledged status as typical spoilage organisms on MAP meats.
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Affiliation(s)
- Sandra Kolbeck
- Lehrstuhl für Technische Mikrobiologie, Technische Universität München, Freising, Germany
| | - Christina Ludwig
- Bayerisches Zentrum für Biomolekulare Massenspektrometrie, Technische Universität München, Freising, Germany
| | - Chen Meng
- Bayerisches Zentrum für Biomolekulare Massenspektrometrie, Technische Universität München, Freising, Germany
| | - Maik Hilgarth
- Lehrstuhl für Technische Mikrobiologie, Technische Universität München, Freising, Germany
| | - Rudi F Vogel
- Lehrstuhl für Technische Mikrobiologie, Technische Universität München, Freising, Germany
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16
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Glowacki RWP, Pudlo NA, Tuncil Y, Luis AS, Sajjakulnukit P, Terekhov AI, Lyssiotis CA, Hamaker BR, Martens EC. A Ribose-Scavenging System Confers Colonization Fitness on the Human Gut Symbiont Bacteroides thetaiotaomicron in a Diet-Specific Manner. Cell Host Microbe 2019; 27:79-92.e9. [PMID: 31901520 DOI: 10.1016/j.chom.2019.11.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 10/03/2019] [Accepted: 11/18/2019] [Indexed: 12/17/2022]
Abstract
Efficient nutrient acquisition in the human gut is essential for microbial persistence. Although polysaccharides have been well-studied nutrients for the gut microbiome, other resources such as nucleic acids and nucleosides are less studied. We describe several ribose-utilization systems (RUSs) that are broadly represented in Bacteroidetes and appear to have diversified to access ribose from a variety of substrates. One Bacteroides thetaiotaomicron RUS variant is critical for competitive gut colonization in a diet-specific fashion. We used molecular genetics to probe the required functions of the system and the nature of the nutrient source(s) underlying this phenotype. Two RUS-encoded ribokinases were the only components required for this effect, presumably because they generate ribose-phosphate derivatives from products of an unlinked but essential nucleoside phosphorylase. Our results underscore the extensive mechanisms that gut symbionts have evolved to access nutrients and the potential for unexpected dependencies among systems that mediate colonization and persistence.
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Affiliation(s)
- Robert W P Glowacki
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Nicholas A Pudlo
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Yunus Tuncil
- Department of Food Science and Whistler Center for Carbohydrate Research, Purdue University, West Lafayette, IN 47907, USA
| | - Ana S Luis
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Peter Sajjakulnukit
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Anton I Terekhov
- Department of Food Science and Whistler Center for Carbohydrate Research, Purdue University, West Lafayette, IN 47907, USA
| | - Costas A Lyssiotis
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Bruce R Hamaker
- Department of Food Science and Whistler Center for Carbohydrate Research, Purdue University, West Lafayette, IN 47907, USA
| | - Eric C Martens
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
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17
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Bui TPN, Schols HA, Jonathan M, Stams AJM, de Vos WM, Plugge CM. Mutual Metabolic Interactions in Co-cultures of the Intestinal Anaerostipes rhamnosivorans With an Acetogen, Methanogen, or Pectin-Degrader Affecting Butyrate Production. Front Microbiol 2019; 10:2449. [PMID: 31736896 PMCID: PMC6839446 DOI: 10.3389/fmicb.2019.02449] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 10/11/2019] [Indexed: 12/31/2022] Open
Abstract
The human intestinal tract harbors diverse and complex microbial communities that have a vast metabolic capacity including the breakdown of complex carbohydrates into short chain fatty acids, acetate, propionate, and butyrate. As butyrate is beneficial for gut health there is much attention on butyrogenic bacteria and their role in the colonic anaerobic food chain. However, our understanding how production of butyrate by gut microorganisms is controlled by interactions between different species and environmental nutrient availability is very limited. To address this, we set up experimental in vitro co-culture systems to study the metabolic interactions of Anaerostipes rhamnosivorans, a butyrate producer with each of its partners; Blautia hydrogenotrophica, an acetogen; Methanobrevibacter smithii, a methanogen and Bacteroides thetaiotaomicron, a versatile degrader of plant cell wall pectins; through corresponding specific cross-feeding. In all co-cultures, A. rhamnosivorans was able to benefit from its partner for enhanced butyrate formation compared to monocultures. Interspecies transfer of hydrogen or formate from A. rhamnosivorans to the acetogen B. hydrogenotrophica and in turn of acetate from the acetogen to the butyrogen were essential for butyrate formation. A. rhamnosivorans grown on glucose supported growth of M. smithii via interspecies formate/hydrogen transfer enhancing butyrate formation. In the co-culture with pectin, lactate was released by B. thetaiotaomicron which was concomitantly used by A. rhamnosivorans for the production of butyrate. Our findings indicate enhanced butyrate formation through microbe-microbe interactions between A. rhamnosivorans and an acetogen, a methanogen or a pectin-degrader. Such microbial interactions enhancing butyrate formation may be beneficial for colonic health.
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Affiliation(s)
- Thi Phuong Nam Bui
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, Netherlands
| | - Henk A Schols
- Laboratory of Food Chemistry, Wageningen University & Research, Wageningen, Netherlands
| | - Melliana Jonathan
- Laboratory of Food Chemistry, Wageningen University & Research, Wageningen, Netherlands
| | - Alfons J M Stams
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, Netherlands
| | - Willem M de Vos
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, Netherlands.,Human Microbiome Research Programme, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Caroline M Plugge
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, Netherlands
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18
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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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19
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Imlay JA, Sethu R, Rohaun SK. Evolutionary adaptations that enable enzymes to tolerate oxidative stress. Free Radic Biol Med 2019; 140:4-13. [PMID: 30735836 PMCID: PMC6684875 DOI: 10.1016/j.freeradbiomed.2019.01.048] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Accepted: 01/31/2019] [Indexed: 10/27/2022]
Abstract
Biochemical mechanisms emerged and were integrated into the metabolic plan of cellular life long before molecular oxygen accumulated in the biosphere. When oxygen levels finaly rose, they threatened specific types of enzymes: those that use organic radicals as catalysts, and those that depend upon iron centers. Nature has found ways to ensure that such enzymes are still used by contemporary organisms. In some cases they are restricted to microbes that reside in anoxic habitats, but in others they manage to function inside aerobic cells. In the latter case, it is frequently true that the ancestral enzyme has been modified to fend off poisoning. In this review we survey a range of protein adaptations that permit radical-based and low-potential iron chemistry to succeed in oxic environments. In many cases, accessory domains shield the vulnerable radical or metal center from oxygen. In others, the structures of iron cofactors evolved to less oxidizable forms, or alternative metals replaced iron altogether. The overarching view is that some classes of biochemical mechanism are intrinsically incompatible with the presence of oxygen. The structural modification of target enzymes is an under-recognized response to this problem.
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Affiliation(s)
- James A Imlay
- Department of Microbiology, University of Illinois, 601 S. Goodwin Ave, Urbana, IL, 61801, USA.
| | - Ramakrishnan Sethu
- Department of Microbiology, University of Illinois, 601 S. Goodwin Ave, Urbana, IL, 61801, USA
| | - Sanjay Kumar Rohaun
- Department of Microbiology, University of Illinois, 601 S. Goodwin Ave, Urbana, IL, 61801, USA
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20
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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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21
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Stairs CW, Kokla A, Ástvaldsson Á, Jerlström-Hultqvist J, Svärd S, Ettema TJG. Oxygen induces the expression of invasion and stress response genes in the anaerobic salmon parasite Spironucleus salmonicida. BMC Biol 2019; 17:19. [PMID: 30823887 PMCID: PMC6397501 DOI: 10.1186/s12915-019-0634-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 02/06/2019] [Indexed: 01/01/2023] Open
Abstract
Background Spironucleus salmonicida is an anaerobic parasite that can cause systemic infections in Atlantic salmon. Unlike other diplomonad parasites, such as the human pathogen Giardia intestinalis, Spironucleus species can infiltrate the blood stream of their hosts eventually colonizing organs, skin and gills. How this presumed anaerobe can persist and invade oxygenated tissues, despite having a strictly anaerobic metabolism, remains elusive. Results To investigate how S. salmonicida response to oxygen stress, we performed RNAseq transcriptomic analyses of cells grown in the presence of oxygen or antioxidant-free medium. We found that over 20% of the transcriptome is differentially regulated in oxygen (1705 genes) and antioxidant-depleted (2280 genes) conditions. These differentially regulated transcripts encode proteins related to anaerobic metabolism, cysteine and Fe-S cluster biosynthesis, as well as a large number of proteins of unknown function. S. salmonicida does not encode genes involved in the classical elements of oxygen metabolism (e.g., catalases, superoxide dismutase, glutathione biosynthesis, oxidative phosphorylation). Instead, we found that genes encoding bacterial-like oxidoreductases were upregulated in response to oxygen stress. Phylogenetic analysis revealed some of these oxygen-responsive genes (e.g., nadh oxidase, rubrerythrin, superoxide reductase) are rare in eukaryotes and likely derived from lateral gene transfer (LGT) events into diplomonads from prokaryotes. Unexpectedly, we observed that many host evasion- and invasion-related genes were also upregulated under oxidative stress suggesting that oxygen might be an important signal for pathogenesis. Conclusion While oxygen is toxic for related organisms, such as G. intestinalis, we find that oxygen is likely a gene induction signal for host invasion- and evasion-related pathways in S. salmonicida. These data provide the first molecular evidence for how S. salmonicida could tolerate oxic host environments and demonstrate how LGT can have a profound impact on the biology of anaerobic parasites. Electronic supplementary material The online version of this article (10.1186/s12915-019-0634-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Courtney W Stairs
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden.
| | - Anna Kokla
- Present Address: Department of Plant Biology, Swedish University of Agricultural Sciences (SLU), Almas Allé 5, BioCentrum, room D-444, Uppsala, Sweden
| | - Ásgeir Ástvaldsson
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Jon Jerlström-Hultqvist
- Present Address: Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Canada
| | - Staffan Svärd
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Thijs J G Ettema
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden.,Laboratory of Microbiology, Department of Agrotechnology and Food Sciences, Wageningen University, Stippeneng 4, 6708WE, Wageningen, The Netherlands
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22
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Spiga L, Winter SE. Using Enteric Pathogens to Probe the Gut Microbiota. Trends Microbiol 2019; 27:243-253. [DOI: 10.1016/j.tim.2018.11.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 11/08/2018] [Accepted: 11/19/2018] [Indexed: 12/23/2022]
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23
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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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24
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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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25
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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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Endogenous superoxide is a key effector of the oxygen sensitivity of a model obligate anaerobe. Proc Natl Acad Sci U S A 2018; 115:E3266-E3275. [PMID: 29559534 DOI: 10.1073/pnas.1800120115] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
It has been unclear whether superoxide and/or hydrogen peroxide play important roles in the phenomenon of obligate anaerobiosis. This question was explored using Bacteroides thetaiotaomicron, a major fermentative bacterium in the human gastrointestinal tract. Aeration inactivated two enzyme families-[4Fe-4S] dehydratases and nonredox mononuclear iron enzymes-whose homologs, in contrast, remain active in aerobic Escherichia coli Inactivation-rate measurements of one such enzyme, B. thetaiotaomicron fumarase, showed that it is no more intrinsically sensitive to oxidants than is an E. coli fumarase. Indeed, when the E. coli enzymes were expressed in B. thetaiotaomicron, they no longer could tolerate aeration; conversely, the B. thetaiotaomicron enzymes maintained full activity when expressed in aerobic E. coli Thus, the aerobic inactivation of the B. thetaiotaomicron enzymes is a feature of their intracellular environment rather than of the enzymes themselves. B. thetaiotaomicron possesses superoxide dismutase and peroxidases, and it can repair damaged enzymes. However, measurements confirmed that the rate of reactive oxygen species production inside aerated B. thetaiotaomicron is far higher than in E. coli Analysis of the damaged enzymes recovered from aerated B. thetaiotaomicron suggested that they had been inactivated by superoxide rather than by hydrogen peroxide. Accordingly, overproduction of superoxide dismutase substantially protected the enzymes from aeration. We conclude that when this anaerobe encounters oxygen, its internal superoxide levels rise high enough to inactivate key catabolic and biosynthetic enzymes. Superoxide thus comprises a major element of the oxygen sensitivity of this anaerobe. The extent to which molecular oxygen exerts additional direct effects remains to be determined.
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27
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Tegtmeier D, Belitz A, Radek R, Heimerl T, Brune A. Ereboglobus luteus gen. nov. sp. nov. from cockroach guts, and new insights into the oxygen relationship of the genera Opitutus and Didymococcus ( Verrucomicrobia : Opitutaceae ). Syst Appl Microbiol 2018; 41:101-112. [DOI: 10.1016/j.syapm.2017.10.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 10/19/2017] [Accepted: 10/28/2017] [Indexed: 11/25/2022]
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28
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Iwadate Y, Kato JI. Involvement of the ytfK gene from the PhoB regulon in stationary-phase H 2 O 2 stress tolerance in Escherichia coli. Microbiology (Reading) 2017; 163:1912-1923. [DOI: 10.1099/mic.0.000534] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Yumi Iwadate
- Department of Biological Sciences, Graduate Schools of Science and Engineering, Tokyo Metropolitan University, Tokyo 192-0397, Japan
| | - Jun-ichi Kato
- Department of Biological Sciences, Graduate Schools of Science and Engineering, Tokyo Metropolitan University, Tokyo 192-0397, Japan
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29
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Pineda E, Perdomo D. Entamoeba histolytica under Oxidative Stress: What Countermeasure Mechanisms Are in Place? Cells 2017; 6:cells6040044. [PMID: 29160807 PMCID: PMC5755502 DOI: 10.3390/cells6040044] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 11/17/2017] [Accepted: 11/17/2017] [Indexed: 02/06/2023] Open
Abstract
Entamoeba histolytica is the causative agent of human amoebiasis; it affects 50 million people worldwide and causes approximately 100,000 deaths per year. Entamoeba histolytica is an anaerobic parasite that is primarily found in the colon; however, for unknown reasons, it can become invasive, breaching the gut barrier and migrating toward the liver causing amoebic liver abscesses. During the invasive process, it must maintain intracellular hypoxia within the oxygenated human tissues and cellular homeostasis during the host immune defense attack when it is confronted with nitric oxide and reactive oxygen species. But how? This review will address the described and potential mechanisms available to counter the oxidative stress generated during invasion and the possible role that E. histolytica’s continuous endoplasmic reticulum (Eh-ER) plays during these events.
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Affiliation(s)
- Erika Pineda
- Laboratory of Fundamental Microbiology and Pathogenicity (MFP), University of Bordeaux, CNRS UMR-5234, 33000 Bordeaux, France.
| | - Doranda Perdomo
- Laboratory of Fundamental Microbiology and Pathogenicity (MFP), University of Bordeaux, CNRS UMR-5234, 33000 Bordeaux, France.
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30
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Yahara K, Méric G, Taylor AJ, de Vries SPW, Murray S, Pascoe B, Mageiros L, Torralbo A, Vidal A, Ridley A, Komukai S, Wimalarathna H, Cody AJ, Colles FM, McCarthy N, Harris D, Bray JE, Jolley KA, Maiden MCJ, Bentley SD, Parkhill J, Bayliss CD, Grant A, Maskell D, Didelot X, Kelly DJ, Sheppard SK. Genome-wide association of functional traits linked with Campylobacter jejuni survival from farm to fork. Environ Microbiol 2017; 19:361-380. [PMID: 27883255 DOI: 10.1111/1462-2920.13628] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 11/16/2016] [Accepted: 11/18/2016] [Indexed: 01/07/2023]
Abstract
Campylobacter jejuni is a major cause of bacterial gastroenteritis worldwide, primarily associated with the consumption of contaminated poultry. C. jejuni lineages vary in host range and prevalence in human infection, suggesting differences in survival throughout the poultry processing chain. From 7343 MLST-characterised isolates, we sequenced 600 C. jejuni and C. coli isolates from various stages of poultry processing and clinical cases. A genome-wide association study (GWAS) in C. jejuni ST-21 and ST-45 complexes identified genetic elements over-represented in clinical isolates that increased in frequency throughout the poultry processing chain. Disease-associated SNPs were distinct in these complexes, sometimes organised in haplotype blocks. The function of genes containing associated elements was investigated, demonstrating roles for cj1377c in formate metabolism, nuoK in aerobic survival and oxidative respiration, and cj1368-70 in nucleotide salvage. This work demonstrates the utility of GWAS for investigating transmission in natural zoonotic pathogen populations and provides evidence that major C. jejuni lineages have distinct genotypes associated with survival, within the host specific niche, from farm to fork.
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Affiliation(s)
- Koji Yahara
- Department of Bacteriology II, National Institute of Infectious Diseases, Tokyo, Japan
| | - Guillaume Méric
- The Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath, Bath, UK
| | - Aidan J Taylor
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, UK
| | - Stefan P W de Vries
- Department of Veterinary Medicine, University of Cambridge, Madingley, Cambridge, UK
| | - Susan Murray
- Swansea University Medical School, Institute of Life Science, Swansea University, Swansea, UK
| | - Ben Pascoe
- The Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath, Bath, UK.,MRC CLIMB Consortium, Oxford Bath, UK
| | - Leonardos Mageiros
- Swansea University Medical School, Institute of Life Science, Swansea University, Swansea, UK
| | - Alicia Torralbo
- Swansea University Medical School, Institute of Life Science, Swansea University, Swansea, UK
| | - Ana Vidal
- Animal and Plant Health Agency (APHA), Addlestone, UK
| | - Anne Ridley
- Animal and Plant Health Agency (APHA), Addlestone, UK
| | - Sho Komukai
- Department of Bacteriology II, National Institute of Infectious Diseases, Tokyo, Japan
| | | | - Alison J Cody
- Department of Zoology, Oxford University, Oxford, UK
| | | | - Noel McCarthy
- Department of Zoology, Oxford University, Oxford, UK.,NIHR Health Protections Research Unit in Gastrointestinal Infections, University of Oxford, Oxford, UK
| | - David Harris
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
| | - James E Bray
- Department of Zoology, Oxford University, Oxford, UK
| | | | - Martin C J Maiden
- Department of Zoology, Oxford University, Oxford, UK.,NIHR Health Protections Research Unit in Gastrointestinal Infections, University of Oxford, Oxford, UK
| | - Stephen D Bentley
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
| | - Julian Parkhill
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
| | | | - Andrew Grant
- Department of Veterinary Medicine, University of Cambridge, Madingley, Cambridge, UK
| | - Duncan Maskell
- Department of Veterinary Medicine, University of Cambridge, Madingley, Cambridge, UK
| | - Xavier Didelot
- Department of Infectious Disease Epidemiology, Imperial College, London, UK
| | - David J Kelly
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, UK
| | - Samuel K Sheppard
- The Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath, Bath, UK.,MRC CLIMB Consortium, Oxford Bath, UK.,Department of Zoology, Oxford University, Oxford, UK
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31
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The Fumarate Reductase of Bacteroides thetaiotaomicron, unlike That of Escherichia coli, Is Configured so that It Does Not Generate Reactive Oxygen Species. mBio 2017; 8:mBio.01873-16. [PMID: 28049145 PMCID: PMC5210497 DOI: 10.1128/mbio.01873-16] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The impact of oxidative stress upon organismal fitness is most apparent in the phenomenon of obligate anaerobiosis. The root cause may be multifaceted, but the intracellular generation of reactive oxygen species (ROS) likely plays a key role. ROS are formed when redox enzymes accidentally transfer electrons to oxygen rather than to their physiological substrates. In this study, we confirm that the predominant intestinal anaerobe Bacteroides thetaiotaomicron generates intracellular ROS at a very high rate when it is aerated. Fumarate reductase (Frd) is a prominent enzyme in the anaerobic metabolism of many bacteria, including B. thetaiotaomicron, and prior studies of Escherichia coli Frd showed that the enzyme is unusually prone to ROS generation. Surprisingly, in this study biochemical analysis demonstrated that the B. thetaiotaomicron Frd does not react with oxygen at all: neither superoxide nor hydrogen peroxide is formed. Subunit-swapping experiments indicated that this difference does not derive from the flavoprotein subunit at which ROS normally arise. Experiments with the related enzyme succinate dehydrogenase discouraged the hypothesis that heme moieties are responsible. Thus, resistance to oxidation may reflect a shift of electron density away from the flavin moiety toward the iron-sulfur clusters. This study shows that the autoxidizability of a redox enzyme can be suppressed by subtle modifications that do not compromise its physiological function. One implication is that selective pressures might enhance the oxygen tolerance of an organism by manipulating the electronic properties of its redox enzymes so they do not generate ROS. IMPORTANCE Whether in sediments or pathogenic biofilms, the structures of microbial communities are configured around the sensitivities of their members to oxygen. Oxygen triggers the intracellular formation of reactive oxygen species (ROS), and the sensitivity of a microbe to oxygen likely depends upon the rates at which ROS are formed inside it. This study supports that idea, as an obligate anaerobe was confirmed to generate ROS very rapidly upon aeration. However, the suspected source of the ROS was disproven, as the fumarate reductase of the anaerobe did not display the high oxidation rate of its E. coli homologue. Evidently, adjustments in its electronic structure can suppress the tendency of an enzyme to generate ROS. Importantly, this outcome suggests that evolutionary pressure may succeed in modifying redox enzymes and thereby diminishing the stress that an organism experiences in oxic environments. The actual source of ROS in the anaerobe remains to be discovered.
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32
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Tomin M, Tomić S. Dynamic properties of dipeptidyl peptidase III from Bacteroides thetaiotaomicron and the structural basis for its substrate specificity – a computational study. MOLECULAR BIOSYSTEMS 2017; 13:2407-2417. [PMID: 28971197 DOI: 10.1039/c7mb00310b] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Dynamics and enzyme activity of dipeptidyl peptidase III, wild type and mutants, from the human gut symbiont Bacteroides thetaiotaomicron.
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Affiliation(s)
- M. Tomin
- Division of Organic Chemistry and Biochemistry
- Rudjer Boskovic Institute
- Croatia
| | - S. Tomić
- Division of Organic Chemistry and Biochemistry
- Rudjer Boskovic Institute
- Croatia
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33
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Hochart-Behra AC, Drobecq H, Tourret M, Dubreuil L, Behra-Miellet J. Anti-stress proteins produced by Bacteroides thetaiotaomicron after nutrient starvation. Anaerobe 2014; 28:18-23. [DOI: 10.1016/j.anaerobe.2014.04.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Revised: 04/02/2014] [Accepted: 04/17/2014] [Indexed: 11/24/2022]
Affiliation(s)
- Anne-Cécile Hochart-Behra
- Univ Lille Nord de France, F-59000 Lille, France; UDSL, EA 4481, UFR Pharmacie, F-59000 Lille, France; CHArmentières, F-59280, France; Faculté de Pharmacie, Laboratoire de Bactériologie, 3 rue du Pr Laguesse, BP 83, 59006 Lille Cedex, France.
| | - Hervé Drobecq
- Univ Lille Nord de France, F-59000 Lille, France; Peptide CSB Platform, IBL, 59000, Lille, France; Institut de Biologie de Lille, 1 rue du Pr Calmette, 59000 Lille, France.
| | - Mélissa Tourret
- Univ Lille Nord de France, F-59000 Lille, France; UDSL, EA 4481, UFR Pharmacie, F-59000 Lille, France; Faculté de Pharmacie, Laboratoire de Bactériologie, 3 rue du Pr Laguesse, BP 83, 59006 Lille Cedex, France.
| | - Luc Dubreuil
- Univ Lille Nord de France, F-59000 Lille, France; UDSL, U995, 59000 Lille, France; Faculté de Pharmacie, Laboratoire de Bactériologie, 3 rue du Pr Laguesse, BP 83, 59006 Lille Cedex, France.
| | - Josette Behra-Miellet
- Univ Lille Nord de France, F-59000 Lille, France; UDSL, EA 4481, UFR Pharmacie, F-59000 Lille, France; Faculté de Pharmacie, Laboratoire de Bactériologie, 3 rue du Pr Laguesse, BP 83, 59006 Lille Cedex, France.
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34
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Sheng Y, Abreu IA, Cabelli DE, Maroney MJ, Miller AF, Teixeira M, Valentine JS. Superoxide dismutases and superoxide reductases. Chem Rev 2014; 114:3854-918. [PMID: 24684599 PMCID: PMC4317059 DOI: 10.1021/cr4005296] [Citation(s) in RCA: 587] [Impact Index Per Article: 58.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Indexed: 11/30/2022]
Affiliation(s)
- Yuewei Sheng
- Department
of Chemistry and Biochemistry, University
of California Los Angeles, Los
Angeles, California 90095, United States
| | - Isabel A. Abreu
- Instituto
de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157, Oeiras, Portugal
- Instituto
de Biologia Experimental e Tecnológica, Av. da República,
Qta. do Marquês, Estação Agronómica Nacional,
Edificio IBET/ITQB, 2780-157, Oeiras, Portugal
| | - Diane E. Cabelli
- Chemistry
Department, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Michael J. Maroney
- Department
of Chemistry, University of Massachusetts
Amherst, Amherst, Massachusetts 01003, United States
| | - Anne-Frances Miller
- Department
of Chemistry, University of Kentucky, Lexington, Kentucky 40506-0055, United States
| | - Miguel Teixeira
- Instituto
de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157, Oeiras, Portugal
| | - Joan Selverstone Valentine
- Department
of Chemistry and Biochemistry, University
of California Los Angeles, Los
Angeles, California 90095, United States
- Department
of Bioinspired Sciences, Ewha Womans University, Seoul 120-750, Republic of Korea
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35
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H(2)O(2) production in species of the Lactobacillus acidophilus group: a central role for a novel NADH-dependent flavin reductase. Appl Environ Microbiol 2014; 80:2229-39. [PMID: 24487531 DOI: 10.1128/aem.04272-13] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Hydrogen peroxide production is a well-known trait of many bacterial species associated with the human body. In the presence of oxygen, the probiotic lactic acid bacterium Lactobacillus johnsonii NCC 533 excretes up to 1 mM H(2)O(2), inducing growth stagnation and cell death. Disruption of genes commonly assumed to be involved in H(2)O(2) production (e.g., pyruvate oxidase, NADH oxidase, and lactate oxidase) did not affect this. Here we describe the purification of a novel NADH-dependent flavin reductase encoded by two highly similar genes (LJ_0548 and LJ_0549) that are conserved in lactobacilli belonging to the Lactobacillus acidophilus group. The genes are predicted to encode two 20-kDa proteins containing flavin mononucleotide (FMN) reductase conserved domains. Reductase activity requires FMN, flavin adenine dinucleotide (FAD), or riboflavin and is specific for NADH and not NADPH. The Km for FMN is 30 ± 8 μM, in accordance with its proposed in vivo role in H(2)O(2) production. Deletion of the encoding genes in L. johnsonii led to a 40-fold reduction of hydrogen peroxide formation. H(2)O(2) production in this mutant could only be restored by in trans complementation of both genes. Our work identifies a novel, conserved NADH-dependent flavin reductase that is prominently involved in H(2)O(2) production in L. johnsonii.
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36
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Kendall JJ, Barrero-Tobon AM, Hendrixson DR, Kelly DJ. Hemerythrins in the microaerophilic bacterium Campylobacter jejuni help protect key iron-sulphur cluster enzymes from oxidative damage. Environ Microbiol 2013; 16:1105-21. [PMID: 24245612 PMCID: PMC4257069 DOI: 10.1111/1462-2920.12341] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Accepted: 11/12/2013] [Indexed: 01/27/2023]
Abstract
Microaerophilic bacteria are adapted to low oxygen environments, but the mechanisms by which their growth in air is inhibited are not well understood. The citric acid cycle in the microaerophilic pathogen Campylobacter jejuni is potentially vulnerable, as it employs pyruvate and 2-oxoglutarate:acceptor oxidoreductases (Por and Oor), which contain labile (4Fe-4S) centres. Here, we show that both enzymes are rapidly inactivated after exposure of cells to a fully aerobic environment. We investigated the mechanisms that might protect enzyme activity and identify a role for the hemerythrin HerA (Cj0241). A herA mutant exhibits an aerobic growth defect and reduced Por and Oor activities after exposure to 21% (v/v) oxygen. Slow anaerobic recovery of these activities after oxygen damage was observed, but at similar rates in both wild-type and herA strains, suggesting the role of HerA is to prevent Fe-S cluster damage, rather than promote repair. Another hemerythrin (HerB; Cj1224) also plays a protective role. Purified HerA and HerB exhibited optical absorption, ligand binding and resonance Raman spectra typical of μ-oxo-bridged di-iron containing hemerythrins. We conclude that oxygen lability and poor repair of Por and Oor are major contributors to microaerophily in C. jejuni; hemerythrins help prevent enzyme damage microaerobically or during oxygen transients.
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Affiliation(s)
- John J Kendall
- Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield, UK
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37
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Mishra S, Imlay JA. An anaerobic bacterium, Bacteroides thetaiotaomicron, uses a consortium of enzymes to scavenge hydrogen peroxide. Mol Microbiol 2013; 90:1356-71. [PMID: 24164536 DOI: 10.1111/mmi.12438] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/19/2013] [Indexed: 12/17/2022]
Abstract
Obligate anaerobes are periodically exposed to oxygen, and it has been conjectured that on such occasions their low-potential biochemistry will predispose them to rapid ROS formation. We sought to identify scavenging enzymes that might protect the anaerobe Bacteroides thetaiotaomicron from the H2 O2 that would be formed. Genetic analysis of eight candidate enzymes revealed that four of these scavenge H2 O2 in vivo: rubrerythrins 1 and 2, AhpCF, and catalase E. The rubrerythrins served as key peroxidases under anoxic conditions. However, they quickly lost activity upon aeration, and AhpCF and catalase were induced to compensate. The AhpCF is an NADH peroxidase that effectively degraded low micromolar levels of H2 O2 , while the catalytic cycle of catalase enabled it to quickly degrade higher concentrations that might arise from exogenous sources. Using a non-scavenging mutant we verified that endogenous H2 O2 formation was much higher in aerated B. thetaiotaomicron than in Escherichia coli. Indeed, the OxyR stress response to H2 O2 was induced when B. thetaiotaomicron was aerated, and in that circumstance this response was necessary to forestall cell death. Thus aeration is a serious threat for this obligate anaerobe, and to cope it employs a set of defences that includes a repertoire of complementary scavenging enzymes.
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Affiliation(s)
- Surabhi Mishra
- Department of Microbiology, University of Illinois, Urbana, IL, 61801, USA
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38
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Vukelić B, Salopek-Sondi B, Špoljarić J, Sabljić I, Meštrović N, Agić D, Abramić M. Reactive cysteine in the active-site motif of Bacteroides thetaiotaomicron dipeptidyl peptidase III is a regulatory residue for enzyme activity. Biol Chem 2013; 393:37-46. [PMID: 22628297 DOI: 10.1515/bc-2011-193] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Accepted: 11/17/2011] [Indexed: 11/15/2022]
Abstract
Dipeptidyl peptidase III (DPP III), a member of the metallopeptidase family M49, was considered as an exclusively eukaryotic enzyme involved in intracellular peptide catabolism and pain modulation. In 2003, new data on genome sequences revealed the first prokaryotic orthologs, which showed low sequence similarity to eukaryotic ones and a cysteine (Cys) residue in the zinc-binding motif HEXXGH. Here we report the cloning and heterologous expression of DPP III from the human gut symbiont Bacteroides thetaiotaomicron. The catalytic efficiency of bacterial DPP III for preferred synthetic substrate hydrolysis was very similar to that of the human host enzyme. Substitution of Cys450 from the active-site motif by serine did not substantially change the enzymatic activity. However, this residue was wholly responsible for the inactivation effect of sulfhydryl reagents. Molecular modeling indicated seven basic amino acid residues in the local environment of Cys450 as a possible cause for its high reactivity. Sequence analysis of 81 bacterial M49 peptidases showed conservation of the HECLGH motif in 68 primary structures with the majority of proteins lacking an active-site Cys originated from aerobic bacteria. Data obtained suggest that Cys450 of B. thetaiotaomicron DPP III is a regulatory residue for the enzyme activity.
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Affiliation(s)
- Bojana Vukelić
- Division of Organic Chemistry and Biochemistry, Rudjer Bošković Institute, Bijenička cesta 54, 10002 Zagreb, Croatia
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39
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Inactivation of a single gene enables microaerobic growth of the obligate anaerobe Bacteroides fragilis. Proc Natl Acad Sci U S A 2012; 109:12153-8. [PMID: 22778399 DOI: 10.1073/pnas.1203796109] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Bacteroides fragilis can replicate in atmospheres containing ≤0.05% oxygen, but higher concentrations arrest growth by an unknown mechanism. Here we show that inactivation of a single gene, oxe (i.e., oxygen enabled) in B. fragilis allows for growth in concentrations as high as 2% oxygen while increasing the tolerance of this organism to room air. Known components of the oxidative stress response including the ahpC, kat, batA-E, and tpx genes were not individually important for microaerobic growth. However, a Δoxe strain scavenged H(2)O(2) at a faster rate than WT, indicating that reactive oxygen species may play a critical role in limiting growth of this organism to low-oxygen environments. Clinical isolates of B. fragilis displayed a greater capacity for growth under microaerobic conditions than fecal isolates, with some encoding polymorphisms in oxe. Additionally, isolation of oxygen-enabled mutants of Bacteroides thetaiotaomicron suggests that Oxe may mediate growth arrest of other anaerobes in oxygenated environments.
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40
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Koropatkin NM, Cameron EA, Martens EC. How glycan metabolism shapes the human gut microbiota. Nat Rev Microbiol 2012; 10:323-35. [PMID: 22491358 DOI: 10.1038/nrmicro2746] [Citation(s) in RCA: 933] [Impact Index Per Article: 77.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Symbiotic microorganisms that reside in the human intestine are adept at foraging glycans and polysaccharides, including those in dietary plants (starch, hemicellulose and pectin), animal-derived cartilage and tissue (glycosaminoglycans and N-linked glycans), and host mucus (O-linked glycans). Fluctuations in the abundance of dietary and endogenous glycans, combined with the immense chemical variation among these molecules, create a dynamic and heterogeneous environment in which gut microorganisms proliferate. In this Review, we describe how glycans shape the composition of the gut microbiota over various periods of time, the mechanisms by which individual microorganisms degrade these glycans, and potential opportunities to intentionally influence this ecosystem for better health and nutrition.
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Affiliation(s)
- Nicole M Koropatkin
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA
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41
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Meehan BM, Malamy MH. Fumarate reductase is a major contributor to the generation of reactive oxygen species in the anaerobe Bacteroides fragilis. MICROBIOLOGY-SGM 2011; 158:539-546. [PMID: 22075026 DOI: 10.1099/mic.0.054403-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Despite the detrimental role that endogenously generated reactive oxygen species (ROS) may play in bacteria exposed to aerobic environments, very few sources of ROS have been identified in vivo. Such studies are often precluded by the presence of efficient ROS-scavenging pathways, like those found in the aerotolerant anaerobe Bacteroides fragilis. Here we demonstrate that deletion of the genes encoding catalase (Kat), alkylhydroperoxide reductase (AhpC) and thioredoxin-dependent peroxidase (Tpx) strongly inhibits H(2)O(2) detoxification in B. fragilis, thereby allowing for the quantification of ROS production. Exogenous fumarate significantly reduced H(2)O(2) production in a ΔahpCΔkatΔtpx B. fragilis strain, as did deletion of fumarate reductase subunit c (frdC). Deletion of frdC also increased the aerotolerance of a strain lacking superoxide dismutase, indicating that fumarate reductase is a major contributor to ROS formation in B. fragilis exposed to oxygen.
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Affiliation(s)
- Brian M Meehan
- Department of Molecular Biology and Microbiology, Tufts University Sackler School of Graduate Biomedical Sciences, Boston, MA 02111, USA
| | - Michael H Malamy
- Department of Molecular Biology and Microbiology, Tufts University Sackler School of Graduate Biomedical Sciences, Boston, MA 02111, USA
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42
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Hunger S, Gößner AS, Drake HL. Trophic links between the acetogen Clostridium glycolicum KHa and the fermentative anaerobe Bacteroides xylanolyticus KHb, isolated from Hawaiian forest soil. Appl Environ Microbiol 2011; 77:6281-5. [PMID: 21764978 PMCID: PMC3165425 DOI: 10.1128/aem.05519-11] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2011] [Accepted: 07/02/2011] [Indexed: 11/20/2022] Open
Abstract
Isolate KH was obtained from Hawaiian forest soil and found to be composed of two functionally linked anaerobes, KHa and KHb. Gene analyses (16S rRNA, fhs, cooS) identified KHa as an acetogenic strain of Clostridium glycolicum and KHb as Bacteroides xylanolyticus. KHb fermented xylan and other saccharides that KHa could not utilize and formed products (e.g., ethanol and H(2)) that supported the acetogenic growth of KHa.
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Affiliation(s)
| | | | - Harold L. Drake
- Department of Ecological Microbiology, University of Bayreuth, 95440 Bayreuth, Germany
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43
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Voidarou C, Bezirtzoglou E, Alexopoulos A, Plessas S, Stefanis C, Papadopoulos I, Vavias S, Stavropoulou E, Fotou K, Tzora A, Skoufos I. Occurrence of Clostridium perfringens from different cultivated soils. Anaerobe 2011; 17:320-4. [PMID: 21621626 DOI: 10.1016/j.anaerobe.2011.05.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2011] [Accepted: 05/12/2011] [Indexed: 11/25/2022]
Abstract
The occurrence of Clostridium perfringens was estimated in 750 samples originated from a variety of soils bearing various bulb crops: Brawnica oderacea (vegetable), Olea europaea, Daucus carota (carote), Solanum tuberosum (potato), Phaseolus vulgaris (green haricot), Beta vulgaris var. rapaceum (beetroot), Cucurbita pepo (squash), Allium cepa (onion), Cucumis sativus (cucumber) and Capsicum annum (pepper). All isolated strains were tested for their antimicrobial activities to amoxicillin, penicillin G, kanamycin, tetracycline, streptomycin, erythromycin, chloramphenicol and metronidazole. When considering the type of the bulb production, it was observed increased number of C. perfringens spore densities in the most undersurface bulb soils. Moreover, C. perfringens spore are likely to occur in particularly large numbers in soil contaminated by fecal matter. Additionally, there is a close relationship between the spore amount and nature of organic content. Presence of C. perfringens was associated with acidic soil. Most of our strains showed resistance to the studied antibiotics applied usually for human and veterinary care. A systematic monitoring of the cultivated soil ecosystems must include bacteriological parameters together with chemical indices of organic pollution in order to obtain information adequate for assessing their overall quality.
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Affiliation(s)
- C Voidarou
- Technological Educational Institute of Epirus, Arta GR47100, Greece
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44
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Pineda E, Encalada R, Rodríguez-Zavala JS, Olivos-García A, Moreno-Sánchez R, Saavedra E. Pyruvate:ferredoxin oxidoreductase and bifunctional aldehyde-alcohol dehydrogenase are essential for energy metabolism under oxidative stress in Entamoeba histolytica. FEBS J 2010; 277:3382-95. [DOI: 10.1111/j.1742-4658.2010.07743.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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45
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Abstract
Mechanisms of hydrogen peroxide generation in Escherichia coli were investigated using a strain lacking scavenging enzymes. Surprisingly, the deletion of many abundant flavoenzymes that are known to autoxidize in vitro did not substantially lessen overall H(2)O(2) formation. However, H(2)O(2) production diminished by 25-30% when NadB turnover was eliminated. The flavin-dependent desaturating dehydrogenase, NadB uses fumarate as an electron acceptor in anaerobic cells. Experiments showed that aerobic NadB turnover depends upon its oxidation by molecular oxygen, with H(2)O(2) as a product. This reaction appears to be mechanistically adventitious. In contrast, most desaturating dehydrogenases are associated with the respiratory chain and deliver electrons to fumarate anaerobically or oxygen aerobically without the formation of toxic by-products. Presumably, NadB can persist as an H(2)O(2)-generating enzyme because its flux is limited. The anaerobic respiratory enzyme fumarate reductase uses a flavoprotein subunit that is homologous to NadB and accordingly forms substantial H(2)O(2) upon aeration. This tendency is substantially suppressed by cytochrome oxidase. Thus cytochrome d oxidase, which is prevalent among anaerobes, may diminish intracellular H(2)O(2) formation by the anaerobic respiratory chain, whenever these organisms encounter oxygen. These two examples reveal biochemical and physiological arrangements through which evolution has minimized the rate of intracellular oxidant formation.
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Affiliation(s)
- Sergei Korshunov
- Department of Microbiology, University of Illinois, Urbana, IL 61801
| | - James A. Imlay
- Department of Microbiology, University of Illinois, Urbana, IL 61801
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Baughn AD, Garforth SJ, Vilchèze C, Jacobs WR. An anaerobic-type alpha-ketoglutarate ferredoxin oxidoreductase completes the oxidative tricarboxylic acid cycle of Mycobacterium tuberculosis. PLoS Pathog 2009; 5:e1000662. [PMID: 19936047 PMCID: PMC2773412 DOI: 10.1371/journal.ppat.1000662] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2009] [Accepted: 10/22/2009] [Indexed: 11/29/2022] Open
Abstract
Aerobic organisms have a tricarboxylic acid (TCA) cycle that is functionally distinct from those found in anaerobic organisms. Previous reports indicate that the aerobic pathogen Mycobacterium tuberculosis lacks detectable α-ketoglutarate (KG) dehydrogenase activity and drives a variant TCA cycle in which succinyl-CoA is replaced by succinic semialdehyde. Here, we show that M. tuberculosis expresses a CoA-dependent KG dehydrogenase activity, albeit one that is typically found in anaerobic bacteria. Unlike most enzymes of this family, the M. tuberculosis KG: ferredoxin oxidoreductase (KOR) is extremely stable under aerobic conditions. This activity is absent in a mutant strain deleted for genes encoding a previously uncharacterized oxidoreductase, and this strain is impaired for aerobic growth in the absence of sufficient amounts of CO2. Interestingly, inhibition of the glyoxylate shunt or exclusion of exogenous fatty acids alleviates this growth defect, indicating the presence of an alternate pathway that operates in the absence of β-oxidation. Simultaneous disruption of KOR and the first enzyme of the succinic semialdehyde pathway (KG decarboxylase; KGD) results in strict dependence upon the glyoxylate shunt for growth, demonstrating that KG decarboxylase is also functional in M. tuberculosis intermediary metabolism. These observations demonstrate that unlike most organisms M. tuberculosis utilizes two distinct TCA pathways from KG, one that functions concurrently with β-oxidation (KOR-dependent), and one that functions in the absence of β-oxidation (KGD-dependent). As these pathways are regulated by metabolic cues, we predict that their differential utilization provides an advantage for growth in different environments within the host. Knowledge of the basic biology of Mycobacterium tuberculosis is essential to identifying novel ways to combat the emerging threat of drug-resistant tuberculosis. Since the tricarboxylic acid (TCA) cycle is a cornerstone of metabolism and M. tuberculosis does not possess a “typical” TCA cycle enzyme set, much effort has been focused on elucidating the components of this pathway. Previous reports indicate that M. tuberculosis possesses a variant TCA cycle in which succinic semialdehyde replaces succinyl-CoA. Since this pathway does not conserve as much metabolic energy as the canonical pathway, we considered an alternative hypothesis: that M. tuberculosis might possess an anaerobic type α-ketoglutarate dehydrogenase. In this manuscript, we investigate this previously unknown activity for mycobacteria using a combination of genetic and biochemical approaches, and demonstrate that M. tuberculosis is capable of driving a conventional TCA cycle in an unconventional way. We also validate the existence of the previously described variant pathway and provide evidence that these two pathways are differentially utilized in response to a metabolic signal, fatty acid catabolism.
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Affiliation(s)
- Anthony D. Baughn
- Howard Hughes Medical Institute, Albert Einstein College of Medicine, Bronx, New York, United States of America
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Scott J. Garforth
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Catherine Vilchèze
- Howard Hughes Medical Institute, Albert Einstein College of Medicine, Bronx, New York, United States of America
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - William R. Jacobs
- Howard Hughes Medical Institute, Albert Einstein College of Medicine, Bronx, New York, United States of America
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, United States of America
- * E-mail:
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The role of PerR in O2-affected gene expression of Clostridium acetobutylicum. J Bacteriol 2009; 191:6082-93. [PMID: 19648241 DOI: 10.1128/jb.00351-09] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
In the strict anaerobe Clostridium acetobutylicum, a PerR-homologous protein has recently been identified as being a key repressor of a reductive machinery for the scavenging of reactive oxygen species and molecular O(2). In the absence of PerR, the full derepression of its regulon resulted in increased resistance to oxidative stress and nearly full tolerance of an aerobic environment. In the present study, the complementation of a Bacillus subtilis PerR mutant confirmed that the homologous protein from C. acetobutylicum acts as a functional peroxide sensor in vivo. Furthermore, we used a transcriptomic approach to analyze gene expression in the aerotolerant PerR mutant strain and compared it to the O(2) stimulon of wild-type C. acetobutylicum. The genes encoding the components of the alternative detoxification system were PerR regulated. Only few other targets of direct PerR regulation were identified, including two highly expressed genes encoding enzymes that are putatively involved in the central energy metabolism. All of them were highly induced when wild-type cells were exposed to sublethal levels of O(2). Under these conditions, C. acetobutylicum also activated the repair and biogenesis of DNA and Fe-S clusters as well as the transcription of a gene encoding an unknown CO dehydrogenase-like enzyme. Surprisingly few genes were downregulated when exposed to O(2), including those involved in butyrate formation. In summary, these results show that the defense of this strict anaerobe against oxidative stress is robust and by far not limited to the removal of O(2) and its reactive derivatives.
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Mastropaolo MD, Thorson ML, Stevens AM. Comparison of Bacteroides thetaiotaomicron and Escherichia coli 16S rRNA gene expression signals. MICROBIOLOGY-SGM 2009; 155:2683-2693. [PMID: 19443545 DOI: 10.1099/mic.0.027748-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
There are barriers to cross-expression of genes between Bacteroides spp. and Escherichia coli. In this study, a lux-based reporter system was developed for Bacteroides and used to compare the promoter structure and function of a Bacteroides thetaiotaomicron 4001 (BT4001) 16S rRNA promoter with those of E. coli in vivo. Analysis of the BT4001 sequences upstream of the 16S rRNA gene revealed the same overall structure known for E. coli 16S rRNA promoters in that there were two promoters separated by approximately 150 bp. However, the BT4001 16S rRNA promoter contains the proposed Bacteroides -7 and -33 consensus sequences instead of the E. coli -10 and -35 consensus sequences. The biological activity of various configurations of the BT4001 16S rRNA promoter was analysed. Experiments pairing the BT4001 16S rRNA promoter with an E. coli RBS, and vice-versa, confirmed that gene expression between the two species is restricted at the level of transcription. In Bacteroides, a difference in translation initiation also appears to limit expression of foreign genes.
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MESH Headings
- Bacteroides/genetics
- Bacteroides/metabolism
- Base Sequence
- Consensus Sequence
- DNA, Bacterial/analysis
- DNA, Bacterial/genetics
- Escherichia coli/genetics
- Escherichia coli/metabolism
- Gene Expression
- Genes, Reporter
- Genes, rRNA
- Luminescent Measurements/methods
- Molecular Sequence Data
- Photorhabdus/genetics
- Promoter Regions, Genetic
- RNA, Ribosomal, 16S/genetics
- RNA, Ribosomal, 16S/metabolism
- Sequence Analysis, DNA
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Affiliation(s)
- Matthew D Mastropaolo
- Department of Biological Sciences, Virginia Tech, 219 Life Sciences 1, Washington Street, Blacksburg, VA 24061-0910, USA
| | - Mary L Thorson
- Department of Biological Sciences, Virginia Tech, 219 Life Sciences 1, Washington Street, Blacksburg, VA 24061-0910, USA
| | - Ann M Stevens
- Department of Biological Sciences, Virginia Tech, 219 Life Sciences 1, Washington Street, Blacksburg, VA 24061-0910, USA
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Olivos-García A, Saavedra E, Ramos-Martínez E, Nequiz M, Pérez-Tamayo R. Molecular nature of virulence in Entamoeba histolytica. INFECTION GENETICS AND EVOLUTION 2009; 9:1033-7. [PMID: 19376272 DOI: 10.1016/j.meegid.2009.04.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2008] [Revised: 03/30/2009] [Accepted: 04/03/2009] [Indexed: 01/07/2023]
Abstract
For many years virulence of pathogenic Entamoeba histolytica has been attributed to the capacity of the parasite to destroy tissues through the expression and/or secretion of various molecules. Such view is supported mainly by in vitro experimentation, whereas data obtained by using animal models of the disease have clearly demonstrated that the host's inflammatory response is primarily responsible for tissue damage. This review analyzes the content and/or activity of some of the presumed toxic amebic molecules present in amebic strains with different degrees of virulence compared to various parasite in vitro functions that are supposed to correlate with in vivo virulence. The analysis suggests that amebic virulence is primarily determined by the parasite's capacity to adapt and survive the aerobic conditions present in animal tissues. This initial episode in the host-parasite relationship is an absolute requirement for the further development of tissue lesions, which result from the concerted action of many molecules derived from both, the host and the parasite.
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Affiliation(s)
- Alfonso Olivos-García
- Departamento de Medicina Experimental Facultad de Medicina, Universidad Nacional Autónoma de México, México DF, Mexico.
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50
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Thioredoxins in redox maintenance and survival during oxidative stress of Bacteroides fragilis. J Bacteriol 2009; 191:3384-91. [PMID: 19286811 DOI: 10.1128/jb.01665-08] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The anaerobe Bacteroides fragilis is a gram-negative, opportunistic pathogen that is highly aerotolerant and can persist in aerobic environments for extended periods. In this study, the six B. fragilis thioredoxins (Trxs) were investigated to determine their role during oxidative stress. Phylogenetic analyses of Trx protein sequences indicated that four of the six Trxs (TrxA, TrxC, TrxD, and TrxF) belong to the M-type Trx class but were associated with two different M-type lineages. TrxE and TrxG were most closely associated to Y-type Trxs found primarily in cyanobacteria. Single and multiple trx gene deletions were generated to determine functional differences between the Trxs. The trxA gene was essential, but no anaerobic growth defects were observed for any other single trx deletion or for the DeltatrxC DeltatrxD::cfxA DeltatrxE DeltatrxF DeltatrxG quintuple mutant. Regulation of the trx genes was linked to the oxidative stress response, and all were induced by aerobic conditions. The DeltatrxC DeltatrxE DeltatrxF DeltatrxG and the DeltatrxC DeltatrxD::cfxA DeltatrxE DeltatrxF DeltatrxG multiple deletion strains were impaired during growth in oxidized media, but single trx gene mutants did not have a phenotype in this assay. TrxD was protective during exposure to the thiol oxidant diamide, and expression of trxD was induced by diamide. Diamide-induced expression of trxC, trxE, and trxF increased significantly in a trxD mutant strain, suggesting that there is some capacity for compensation in this complex Trx system. These data provide insight into the role of individual Trxs in the B. fragilis oxidative stress response.
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