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Kalapos MP, de Bari L. The evolutionary arch of bioenergetics from prebiotic mechanisms to the emergence of a cellular respiratory chain. Biosystems 2024; 244:105288. [PMID: 39128646 DOI: 10.1016/j.biosystems.2024.105288] [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: 06/04/2024] [Revised: 08/07/2024] [Accepted: 08/07/2024] [Indexed: 08/13/2024]
Abstract
This article proposes an evolutionary trajectory for the development of biological energy producing systems. Six main stages of energy producing system evolution are described, from early evolutionary pyrite-pulled mechanism through the Last Universal Common Ancestor (LUCA) to contemporary systems. We define the Last Pure Chemical Entity (LPCE) as the last completely non-enzymatic entity. LPCE could have had some life-like properties, but lacked genetic information carriers, thus showed greater instability and environmental dependence than LUCA. A double bubble model is proposed for compartmentalization and cellularization as a prerequisite to both highly efficient protein synthesis and transmembrane ion-gradient. The article finds that although LUCA predominantly functioned anaerobically, it was a non-exclusive anaerobe, and sulfur dominated metabolism preceded phosphate dominated one.
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Affiliation(s)
| | - Lidia de Bari
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies, Bari, Italy
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2
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Li X, Chen R, Wen J, Ji R, Chen X, Cao Y, Yu Y, Zhao C. The mechanisms in the gut microbiota regulation and type 2 diabetes therapeutic activity of resistant starches. Int J Biol Macromol 2024; 274:133279. [PMID: 38906356 DOI: 10.1016/j.ijbiomac.2024.133279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 06/12/2024] [Accepted: 06/18/2024] [Indexed: 06/23/2024]
Abstract
Resistant starch (RS) can potentially prevent type 2 diabetes through the modulation of intestinal microbiota and microbial metabolites. Currently, it has been wildly noted that altering the intestinal microbial composition and short-chain fatty acids levels can achieve therapeutic effects, although the specific mechanisms were rarely elucidated. This review systematically explores the structural characteristics of different RS, analyzes the cross-feeding mechanism utilized by intestinal microbiota, and outlines the pathways and targets of butyrate, a primary microbial metabolite, for treating diabetes. Different RS types may have a unique impact on microbiota composition and their cross-feeding, thus exploring regulatory mechanisms of RS on diabetes through intestinal flora interaction and their metabolites could pave the way for more effective treatment outcomes for host health. Furthermore, by understanding the mechanisms of strain-level cross-feeding and metabolites of RS, precise dietary supplementation methods targeted at intestinal composition and metabolites can be achieved to improve T2DM.
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Affiliation(s)
- Xiaoqing Li
- State Key Laboratory of Mariculture Breeding, Key Laboratory of Marine Biotechnology of Fujian Province, Fujian Agriculture and Forestry University, Fuzhou 350002, China; College of Food Science and Engineering, South China University of Technology, Guangzhou 510006, China; Guangdong Provincial Key Laboratory of Nutraceuticals and Functional Foods, College of Food Science, South China Agricultural University, Guangzhou 510642, China; Department of Food Science, University of Massachusetts, Amherst, MA 01003, USA
| | - Ruoxin Chen
- State Key Laboratory of Mariculture Breeding, Key Laboratory of Marine Biotechnology of Fujian Province, Fujian Agriculture and Forestry University, Fuzhou 350002, China; College of Food Science and Engineering, South China University of Technology, Guangzhou 510006, China
| | - Jiahui Wen
- State Key Laboratory of Mariculture Breeding, Key Laboratory of Marine Biotechnology of Fujian Province, Fujian Agriculture and Forestry University, Fuzhou 350002, China; College of Marine Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Ruya Ji
- Department of Food Science, University of Massachusetts, Amherst, MA 01003, USA
| | - Xu Chen
- School of Life and Health Technology, Dongguan University of Technology, Dongguan 523808, China
| | - Yong Cao
- Guangdong Provincial Key Laboratory of Nutraceuticals and Functional Foods, College of Food Science, South China Agricultural University, Guangzhou 510642, China
| | - Yigang Yu
- College of Food Science and Engineering, South China University of Technology, Guangzhou 510006, China
| | - Chao Zhao
- State Key Laboratory of Mariculture Breeding, Key Laboratory of Marine Biotechnology of Fujian Province, Fujian Agriculture and Forestry University, Fuzhou 350002, China; College of Marine Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
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3
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Mook A, Herzog J, Walther P, Dürre P, Bengelsdorf FR. Lactate-mediated mixotrophic co-cultivation of Clostridium drakei and recombinant Acetobacterium woodii for autotrophic production of volatile fatty acids. Microb Cell Fact 2024; 23:213. [PMID: 39061103 PMCID: PMC11282840 DOI: 10.1186/s12934-024-02481-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Accepted: 07/08/2024] [Indexed: 07/28/2024] Open
Abstract
BACKGROUND Acetogens, a diverse group of anaerobic autotrophic bacteria, are promising whole-cell biocatalysts that fix CO2 during their growth. However, because of energetic constraints, acetogens exhibit slow growth and the product spectrum is often limited to acetate. Enabling acetogens to form more valuable products such as volatile fatty acids during autotrophic growth is imperative for cementing their place in the future carbon neutral industry. Co-cultivation of strains with different capabilities has the potential to ease the limiting energetic constraints. The lactate-mediated co-culture of an Acetobacterium woodii mutant strain, capable of lactate production, with the Clostridium drakei SL1 type strain can produce butyrate and hexanoate. In this study, the preceding co-culture is characterized by comparison of monocultures and different co-culture approaches. RESULTS C. drakei grew with H2 + CO2 as main carbon and energy source and thrived when further supplemented with D-lactate. Gas phase components and lactate were consumed in a mixotrophic manner with acetate and butyrate as main products and slight accumulation of hexanoate. Formate was periodically produced and eventually consumed by C. drakei. A lactate-mediated co-culture of the A. woodii [PbgaL_ldhD_NFP] strain, engineered for autotrophic lactate production, and C. drakei produced up to 4 ± 1.7 mM hexanoate and 18.5 ± 5.8 mM butyrate, quadrupling and doubling the respective titers compared to a non-lactate-mediated co-culture. Further co-cultivation experiments revealed the possible advantage of sequential co-culture over concurrent approaches, where both strains are inoculated simultaneously. Scanning electron microscopy of the strains revealed cell-to-cell contact between the co-culture partners. Finally, a combined pathway of A. woodii [PbgaL_ldhD_NFP] and C. drakei for chain-elongation with positive ATP yield is proposed. CONCLUSION Lactate was proven to be a well-suited intermediate to combine the high gas uptake capabilities of A. woodii with the chain-elongation potential of C. drakei. The cell-to-cell contact observed here remains to be further characterized in its nature but hints towards diffusive processes being involved in the co-culture. Furthermore, the metabolic pathways involved are still speculatory for C. drakei and do not fully explain the consumption of formate while H2 + CO2 is available. This study exemplifies the potential of combining metabolically engineered and native bacterial strains in a synthetic co-culture.
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Affiliation(s)
- Alexander Mook
- Institute of Molecular Biology and Biotechnology of Prokaryotes, University of Ulm, Ulm, Germany
| | - Jan Herzog
- Institute of Bioprocess and Biosystems Engineering, Hamburg University of Technology, Hamburg, Germany
| | - Paul Walther
- Central Facility for Electron Microscopy, Ulm University, Ulm, Germany
| | - Peter Dürre
- Institute of Microbiology and Biotechnology, University of Ulm, Ulm, Germany
| | - Frank R Bengelsdorf
- Institute of Molecular Biology and Biotechnology of Prokaryotes, University of Ulm, Ulm, Germany.
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Lyu J, Kapolka N, Gumpper R, Alon A, Wang L, Jain MK, Barros-Álvarez X, Sakamoto K, Kim Y, DiBerto J, Kim K, Glenn IS, Tummino TA, Huang S, Irwin JJ, Tarkhanova OO, Moroz Y, Skiniotis G, Kruse AC, Shoichet BK, Roth BL. AlphaFold2 structures guide prospective ligand discovery. Science 2024; 384:eadn6354. [PMID: 38753765 PMCID: PMC11253030 DOI: 10.1126/science.adn6354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 04/24/2024] [Indexed: 05/18/2024]
Abstract
AlphaFold2 (AF2) models have had wide impact but mixed success in retrospective ligand recognition. We prospectively docked large libraries against unrefined AF2 models of the σ2 and serotonin 2A (5-HT2A) receptors, testing hundreds of new molecules and comparing results with those obtained from docking against the experimental structures. Hit rates were high and similar for the experimental and AF2 structures, as were affinities. Success in docking against the AF2 models was achieved despite differences between orthosteric residue conformations in the AF2 models and the experimental structures. Determination of the cryo-electron microscopy structure for one of the more potent 5-HT2A ligands from the AF2 docking revealed residue accommodations that resembled the AF2 prediction. AF2 models may sample conformations that differ from experimental structures but remain low energy and relevant for ligand discovery, extending the domain of structure-based drug design.
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Affiliation(s)
- Jiankun Lyu
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94158, USA
- The Evnin Family Laboratory of Computational Molecular Discovery, The Rockefeller University, New York, NY 10065, USA
| | - Nicholas Kapolka
- Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599, USA
| | - Ryan Gumpper
- Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599, USA
| | - Assaf Alon
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Liang Wang
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94035, USA
| | - Manish K. Jain
- Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599, USA
| | - Ximena Barros-Álvarez
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94035, USA
| | - Kensuke Sakamoto
- Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599, USA
- National Institute of Mental Health Psychoactive Drug Screening Program (NIMH PDSP), School of Medicine, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599, USA
| | - Yoojoong Kim
- Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599, USA
| | - Jeffrey DiBerto
- Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599, USA
| | - Kuglae Kim
- Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599, USA
| | - Isabella S. Glenn
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94158, USA
| | - Tia A. Tummino
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94158, USA
| | - Sijie Huang
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94158, USA
| | - John J. Irwin
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94158, USA
| | | | - Yurii Moroz
- Chemspace LLC, Kyiv 02094, Ukraine
- Taras Shevchenko National University of Kyiv, Kyiv 01601, Ukraine
- Enamine Ltd., Kyiv 02094, Ukraine
| | - Georgios Skiniotis
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94035, USA
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94304, USA
| | - Andrew C. Kruse
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Brian K. Shoichet
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94158, USA
| | - Bryan L. Roth
- Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599, USA
- National Institute of Mental Health Psychoactive Drug Screening Program (NIMH PDSP), School of Medicine, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599, USA
- Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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Hackmann TJ. The vast landscape of carbohydrate fermentation in prokaryotes. FEMS Microbiol Rev 2024; 48:fuae016. [PMID: 38821505 PMCID: PMC11187502 DOI: 10.1093/femsre/fuae016] [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: 04/05/2024] [Revised: 05/23/2024] [Accepted: 05/29/2024] [Indexed: 06/02/2024] Open
Abstract
Fermentation is a type of metabolism carried out by organisms in environments without oxygen. Despite being studied for over 185 years, the diversity and complexity of this metabolism are just now becoming clear. Our review starts with the definition of fermentation, which has evolved over the years and which we help further refine. We then examine the range of organisms that carry out fermentation and their traits. Over one-fourth of all prokaryotes are fermentative, use more than 40 substrates, and release more than 50 metabolic end products. These insights come from studies analyzing records of thousands of organisms. Next, our review examines the complexity of fermentation at the biochemical level. We map out pathways of glucose fermentation in unprecedented detail, covering over 120 biochemical reactions. We also review recent studies coupling genomics and enzymology to reveal new pathways and enzymes. Our review concludes with practical applications for agriculture, human health, and industry. All these areas depend on fermentation and could be improved through manipulating fermentative microbes and enzymes. We discuss potential approaches for manipulation, including genetic engineering, electrofermentation, probiotics, and enzyme inhibitors. We hope our review underscores the importance of fermentation research and stimulates the next 185 years of study.
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Affiliation(s)
- Timothy J Hackmann
- Department of Animal Science, University of California, Davis, CA 95616, United States
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6
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Dai M, Xu Y, Zhao L, Wu M, Ma H, Zhu L, Li W, Li X, Sun B. Caproicibacter sp. BJN0012, a potential new species isolated from cellar mud for caproic acid production from glucose. J Biotechnol 2024; 388:11-23. [PMID: 38614441 DOI: 10.1016/j.jbiotec.2024.04.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 04/08/2024] [Accepted: 04/09/2024] [Indexed: 04/15/2024]
Abstract
Acids play a crucial role in enhancing the flavor of strong-aroma Baijiu, and among them, caproic acid holds significant importance in determining the flavor of the final product. However, the metabolic synthesis of caproic acid during the production process of Baijiu has received limited attention, resulting in fluctuations in caproic acid content among fermentation batches and generating production instability. Acid-producing bacteria found in the cellar mud are the primary microorganisms responsible for caproic acid synthesis, but there is a lack of research on the related microbial resources and their metabolic properties. Therefore, it is essential to identify and investigate these acid-producing microorganisms from cellar mud to ensure stable caproic acid synthesis. In this study, a unique strain was isolated from the cellar mud, exhibiting a 98.12 % similarity in its 16 S rRNA sequence and an average nucleotide identity of 79.57 % with the reference specie, together with the DNA-DNA hybridization of 23.20 % similarity, confirming the distinct species boundaries. The strain was able to produce 1.22 ± 0.55 g/L caproic acid from glucose. Through genome sequencing, annotation, and bioinformatics analysis, the complete pathway of caproic acid synthesis from glucose was elucidated, and the catalytic mechanism of the key thiolase for caproic acid synthesis was investigated. These findings provide useful fundamental data for revealing the metabolic properties of caproic acid-producing bacteria found in cellar mud.
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Affiliation(s)
- Mengqi Dai
- School of Food and Health, Beijing Technology and Businmmess University, Beijing 100048, China
| | - Youqiang Xu
- School of Food and Health, Beijing Technology and Businmmess University, Beijing 100048, China; Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing Technology and Business University, Beijing 100048, China.
| | - Lei Zhao
- School of Food and Health, Beijing Technology and Businmmess University, Beijing 100048, China
| | - Mengqin Wu
- School of Food and Health, Beijing Technology and Businmmess University, Beijing 100048, China
| | - Huifeng Ma
- Hebei Fenglaiyi Wine Industry Co., Ltd, Xingtai, Hebei province 055550, China
| | - Lining Zhu
- Hebei Fenglaiyi Wine Industry Co., Ltd, Xingtai, Hebei province 055550, China
| | - Weiwei Li
- School of Food and Health, Beijing Technology and Businmmess University, Beijing 100048, China; Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing Technology and Business University, Beijing 100048, China
| | - Xiuting Li
- Key Laboratory of Brewing Microbiome and Enzymatic Molecular Engineering, China General Chamber of Commerce, Beijing 102401, China.
| | - Baoguo Sun
- Key Laboratory of Brewing Molecular Engineering of China Light Industry, Beijing Technology and Business University, Beijing 100048, China; Key Laboratory of Geriatric Nutrition and Health (Beijing Technology and Business University), Ministry of Education, Beijing 100048, China
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7
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Chen H, He X, Jiang HW, Zheng YX, Zhang HN, Wu FL, Xu ZW, Guo SJ, Tao SC. Elucidating the network interactions between 21 secreted Mycobacterium tuberculosis proteins and host proteins: the role of DnaK in enhancing Mtb survival via LDHB. Acta Biochim Biophys Sin (Shanghai) 2024; 56:819-823. [PMID: 38545657 PMCID: PMC11177104 DOI: 10.3724/abbs.2024041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Accepted: 03/12/2024] [Indexed: 05/31/2024] Open
Affiliation(s)
- Hong Chen
- Shanghai Center for Systems BiomedicineKey Laboratory of Systems Biomedicine (Ministry of Education)Shanghai Jiao Tong UniversityShanghai200240China
| | - Xiang He
- College of Basic Medical Science in Shanghai Jiao Tong UniversityShanghai Jiao Tong UniversityShanghai200025China
| | | | - Yun-Xiao Zheng
- Shanghai Center for Systems BiomedicineKey Laboratory of Systems Biomedicine (Ministry of Education)Shanghai Jiao Tong UniversityShanghai200240China
| | - Hai-Nan Zhang
- Institute of NeuroscienceChinese Academy of SciencesShanghai200031China
| | - Fan-Lin Wu
- Key Laboratory of Molecular Module-Based Breeding of High Yield and Abiotic Resistant Plants in Universities of ShandongSchool of AgricultureLudong UniversityYantai264025China
| | - Zhao-Wei Xu
- School of Basic Medical Sciences in Fujian Medical UniversityFujian Medical UniversityFuzhou350112China
| | - Shu-Juan Guo
- Shanghai Center for Systems BiomedicineKey Laboratory of Systems Biomedicine (Ministry of Education)Shanghai Jiao Tong UniversityShanghai200240China
| | - Sheng-Ce Tao
- Shanghai Center for Systems BiomedicineKey Laboratory of Systems Biomedicine (Ministry of Education)Shanghai Jiao Tong UniversityShanghai200240China
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8
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Lyu J, Kapolka N, Gumpper R, Alon A, Wang L, Jain MK, Barros-Álvarez X, Sakamoto K, Kim Y, DiBerto J, Kim K, Tummino TA, Huang S, Irwin JJ, Tarkhanova OO, Moroz Y, Skiniotis G, Kruse AC, Shoichet BK, Roth BL. AlphaFold2 structures template ligand discovery. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.12.20.572662. [PMID: 38187536 PMCID: PMC10769324 DOI: 10.1101/2023.12.20.572662] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
AlphaFold2 (AF2) and RosettaFold have greatly expanded the number of structures available for structure-based ligand discovery, even though retrospective studies have cast doubt on their direct usefulness for that goal. Here, we tested unrefined AF2 models prospectively, comparing experimental hit-rates and affinities from large library docking against AF2 models vs the same screens targeting experimental structures of the same receptors. In retrospective docking screens against the σ2 and the 5-HT2A receptors, the AF2 structures struggled to recapitulate ligands that we had previously found docking against the receptors' experimental structures, consistent with published results. Prospective large library docking against the AF2 models, however, yielded similar hit rates for both receptors versus docking against experimentally-derived structures; hundreds of molecules were prioritized and tested against each model and each structure of each receptor. The success of the AF2 models was achieved despite differences in orthosteric pocket residue conformations for both targets versus the experimental structures. Intriguingly, against the 5-HT2A receptor the most potent, subtype-selective agonists were discovered via docking against the AF2 model, not the experimental structure. To understand this from a molecular perspective, a cryoEM structure was determined for one of the more potent and selective ligands to emerge from docking against the AF2 model of the 5-HT2A receptor. Our findings suggest that AF2 models may sample conformations that are relevant for ligand discovery, much extending the domain of applicability of structure-based ligand discovery.
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Affiliation(s)
- Jiankun Lyu
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94158, USA
- The Evnin Family Laboratory of Computational Molecular Discovery, The Rockefeller University, New York, NY 10065, USA (present address)
| | - Nicholas Kapolka
- Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599-7365, USA
| | - Ryan Gumpper
- Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599-7365, USA
| | - Assaf Alon
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
- Pharmacology Department, Yale School of Medicine, New Haven, CT 06510, USA (present address)
| | - Liang Wang
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Manish K Jain
- Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599-7365, USA
| | - Ximena Barros-Álvarez
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Kensuke Sakamoto
- Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599-7365, USA
- National Institute of Mental Health Psychoactive Drug Screening Program (NIMH PDSP), School of Medicine, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599-7365, USA
| | - Yoojoong Kim
- Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599-7365, USA
| | - Jeffrey DiBerto
- Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599-7365, USA
| | - Kuglae Kim
- Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599-7365, USA
- Department of Pharmacy, College of Pharmacy, Yonsei University, Incheon 21983, Korea (present address)
| | - Tia A Tummino
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94158, USA
| | - Sijie Huang
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94158, USA
| | - John J Irwin
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94158, USA
| | | | - Yurii Moroz
- Chemspace LLC, Kyiv, 02094, Ukraine
- Taras Shevchenko National University of Kyiv, Kyiv, 01601, Ukraine
- Enamine Ltd., Kyiv, 02094, Ukraine
| | - Georgios Skiniotis
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, US
| | - Andrew C Kruse
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Brian K Shoichet
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94158, USA
| | - Bryan L Roth
- Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599-7365, USA
- National Institute of Mental Health Psychoactive Drug Screening Program (NIMH PDSP), School of Medicine, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599-7365, USA
- Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7360, USA
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9
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Park SY, Zhang Y, O'Loughlin EJ, Jo HY, Kwon JS, Kwon MJ. Temperature-dependent microbial reactions by indigenous microbes in bentonite under Fe(III)- and sulfate-reducing conditions. JOURNAL OF HAZARDOUS MATERIALS 2024; 465:133318. [PMID: 38154187 DOI: 10.1016/j.jhazmat.2023.133318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Revised: 12/09/2023] [Accepted: 12/17/2023] [Indexed: 12/30/2023]
Abstract
Bentonite is a promising buffer material for constructing spent nuclear fuel (SNF) repositories. However, indigenous microbes in bentonite can be introduced to the repository and subsequent sealing of the repository develops anoxic conditions over time which may stimulate fermentation and anaerobic respiration, possibly affecting bentonite structure and SNF repository stability. Moreover, the microbial activity in the bentonite can be impacted by the heat generated from radionuclides decay. Therefore, to investigate the temperature effect on microbial activities in bentonite, we created microcosms with WRK bentonil (a commercial bentonite) using lactate as the electron donor, and sulfate and/or ferrihydrite (Fe(III)) as electron acceptors with incubation at 18 ℃ and 50 ℃. Indigenous WRK microbes reduced sulfate and Fe(III) at both temperatures but with different rates and extents. Lactate was metabolized to acetate at both temperatures, but only to propionate at 18 ℃ during early-stage microbial fermentation. More Fe(III)-reduction at 18 ℃ but more sulfate-reduction at 50 ℃ was observed. Thermophilic and/or metabolically flexible microbes were involved in both fermentation and Fe(III)/sulfate reduction. Our findings illustrate the necessity of considering the influence of temperature on microbial activities when employing bentonite as an engineered buffer material in construction of SNF repository barriers.
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Affiliation(s)
- Su-Young Park
- Department of Earth and Environmental Sciences, Korea University, Seoul 02841, South Korea
| | - Yidan Zhang
- Department of Earth and Environmental Sciences, Korea University, Seoul 02841, South Korea
| | | | - Ho Young Jo
- Department of Earth and Environmental Sciences, Korea University, Seoul 02841, South Korea
| | - Jang-Soon Kwon
- Korea Atomic Energy Research Institute, Daejeon 34057, South Korea
| | - Man Jae Kwon
- Department of Earth and Environmental Sciences, Korea University, Seoul 02841, South Korea.
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10
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Martínez-Ruano JA, Suazo A, Véliz F, Otalora F, Conejeros R, González E, Aroca G. Effect of pH on metabolic pathway shift in fermentation and electro-fermentation of xylose by Clostridium autoethanogenum. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 351:119918. [PMID: 38154218 DOI: 10.1016/j.jenvman.2023.119918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 12/06/2023] [Accepted: 12/17/2023] [Indexed: 12/30/2023]
Abstract
Clostridium autoethanogenum can to convert waste gases (CO2, CO, H2) and xylose from hydrolyzed biomass into acetate, lactate, formate, ethanol and 2,3-butanediol, being a candidate for the transformation of waste streams of lignocellulosic biorefineries. Electro-fermentation (EF) modify the pattern of traditional fermentations resulting in improved product yields as has been shown when using Clostridium strains. The aim of this work was to evaluate the influence of pH on microbial growth and product distribution during fermentation and EF of xylose by C. autoethanogenum DSM10061. Fermentation and EF were carried out in a H-type reactor at three controlled pH: 5.0, 5.5 and 5.8, and at a fixed potential of -600 mV (versus Ag/AgCl) in the EF. The experiments showed that maximum biomass concentration increased as the pH increased in fermentation and EF. In accordance with maximum biomass reached, the highest substrate conversion was observed at pH 5.8 for both systems, with 76.80 % in fermentation and 96.18 % in EF. Moreover, the highest concentrations of acetic acid (1.41 ± 0.07 g L-1) and ethanol (1.45 ± 0.15 g L-1) were obtained at the end of cultures in the EF at pH 5.8. The production of lactic and formic acid decreased by the application of the external potential regardless of the pH value, reaching the lowest productivity at pH 5.8. In contrast, the specific productivity of acetic acid and ethanol was lower in both fermentation and EF at the lowest pH. Furthermore, the presence of 0.06 g L-1 of 2,3-butanediol was only detected in EF at pH 5.8. The results revealed that EF modulated microbial metabolism, which can be explained by a possible increased generation of NADP+/NADPH cofactors, which would redirect the metabolic pathway to more reduced products.
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Affiliation(s)
| | - Andrés Suazo
- School of Biochemical Engineering, Pontificia Universidad Católica de Valparaíso, Chile
| | - Fabián Véliz
- School of Biochemical Engineering, Pontificia Universidad Católica de Valparaíso, Chile
| | - Fabián Otalora
- School of Biochemical Engineering, Pontificia Universidad Católica de Valparaíso, Chile
| | - Raúl Conejeros
- School of Biochemical Engineering, Pontificia Universidad Católica de Valparaíso, Chile
| | - Ernesto González
- School of Biochemical Engineering, Pontificia Universidad Católica de Valparaíso, Chile; Department of Chemical and Materials Engineering, Faculty of Chemical Sciences, Universidad Complutense de Madrid, Spain
| | - Germán Aroca
- School of Biochemical Engineering, Pontificia Universidad Católica de Valparaíso, Chile.
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11
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Britton TA, Wu C, Chen YW, Franklin D, Chen Y, Camacho MI, Luong TT, Das A, Ton-That H. The respiratory enzyme complex Rnf is vital for metabolic adaptation and virulence in Fusobacterium nucleatum. mBio 2024; 15:e0175123. [PMID: 38059640 PMCID: PMC10790702 DOI: 10.1128/mbio.01751-23] [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: 07/06/2023] [Accepted: 10/20/2023] [Indexed: 12/08/2023] Open
Abstract
IMPORTANCE This paper illuminates the significant question of how the oral commensal Fusobacterium nucleatum adapts to the metabolically changing environments of several extra-oral sites such as placenta and colon to promote various diseases as an opportunistic pathogen. We demonstrate here that the highly conserved Rhodobacter nitrogen-fixation complex, commonly known as Rnf complex, is key to fusobacterial metabolic adaptation and virulence. Genetic disruption of this Rnf complex causes global defects in polymicrobial interaction, biofilm formation, cell growth and morphology, hydrogen sulfide production, and ATP synthesis. Targeted metabolomic profiling demonstrates that the loss of this respiratory enzyme significantly diminishes catabolism of numerous amino acids, which negatively impacts fusobacterial virulence as tested in a preterm birth model in mice.
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Affiliation(s)
- Timmie A. Britton
- Molecular Biology Institute, University of California, Los Angeles, California, USA
| | - Chenggang Wu
- Department of Microbiology & Molecular Genetics, University of Texas McGovern Medical School, Houston, Texas, USA
| | - Yi-Wei Chen
- Division of Oral & Systemic Health Sciences, School of Dentistry, University of California, Los Angeles, California, USA
| | - Dana Franklin
- Molecular Biology Institute, University of California, Los Angeles, California, USA
| | - Yimin Chen
- Division of Oral & Systemic Health Sciences, School of Dentistry, University of California, Los Angeles, California, USA
| | - Martha I. Camacho
- Division of Oral & Systemic Health Sciences, School of Dentistry, University of California, Los Angeles, California, USA
| | - Truc T. Luong
- Division of Oral & Systemic Health Sciences, School of Dentistry, University of California, Los Angeles, California, USA
| | - Asis Das
- Department of Medicine, Neag Comprehensive Cancer Center, University of Connecticut Health Center, Farmington, Connecticut, USA
| | - Hung Ton-That
- Molecular Biology Institute, University of California, Los Angeles, California, USA
- Division of Oral & Systemic Health Sciences, School of Dentistry, University of California, Los Angeles, California, USA
- Department of Microbiology, Immunology & Molecular Genetics, University of California, Los Angeles, California, USA
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12
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Paudel D, Nair DVT, Tian S, Hao F, Goand UK, Joseph G, Prodes E, Chai Z, Robert CE, Chassaing B, Patterson AD, Singh V. Dietary fiber guar gum-induced shift in gut microbiota metabolism and intestinal immune activity enhances susceptibility to colonic inflammation. Gut Microbes 2024; 16:2341457. [PMID: 38630030 PMCID: PMC11028019 DOI: 10.1080/19490976.2024.2341457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Accepted: 04/04/2024] [Indexed: 04/19/2024] Open
Abstract
With an increasing interest in dietary fibers (DFs) to promote intestinal health and the growth of beneficial gut bacteria, there is a continued rise in the incorporation of refined DFs in processed foods. It is still unclear how refined fibers, such as guar gum, affect the gut microbiota activity and pathogenesis of inflammatory bowel disease (IBD). Our study elucidated the effect and underlying mechanisms of guar gum, a fermentable DF (FDF) commonly present in a wide range of processed foods, on colitis development. We report that guar gum containing diet (GuD) increased the susceptibility to colonic inflammation. Specifically, GuD-fed group exhibited severe colitis upon dextran sulfate sodium (DSS) administration, as evidenced by reduced body weight, diarrhea, rectal bleeding, and shortening of colon length compared to cellulose-fed control mice. Elevated levels of pro-inflammatory markers in both serum [serum amyloid A (SAA), lipocalin 2 (Lcn2)] and colon (Lcn2) and extensive disruption of colonic architecture further affirmed that GuD-fed group exhibited more severe colitis than control group upon DSS intervention. Amelioration of colitis in GuD-fed group pre-treated with antibiotics suggest a vital role of intestinal microbiota in GuD-mediated exacerbation of intestinal inflammation. Gut microbiota composition and metabolite analysis in fecal and cecal contents, respectively, revealed that guar gum primarily enriches Actinobacteriota, specifically Bifidobacterium. Guar gum also altered multiple genera belonging to phyla Bacteroidota and Firmicutes. Such shift in gut microbiota composition favored luminal accumulation of intermediary metabolites succinate and lactate in the GuD-fed mice. Colonic IL-18 and tight junction markers were also decreased in the GuD-fed group. Importantly, GuD-fed mice pre-treated with recombinant IL-18 displayed attenuated colitis. Collectively, unfavorable changes in gut microbiota activity leading to luminal accumulation of lactate and succinate, reduced colonic IL-18, and compromised gut barrier function following guar gum feeding contributed to increased colitis susceptibility.
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Affiliation(s)
- Devendra Paudel
- Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA, USA
| | - Divek V. T. Nair
- Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA, USA
| | - Sangshan Tian
- Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA, USA
| | - Fuhua Hao
- Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, PA, USA
| | - Umesh K. Goand
- Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA, USA
| | - Grace Joseph
- Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA, USA
| | - Eleni Prodes
- Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA, USA
| | - Zhi Chai
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Chloé E.M. Robert
- INSERM U1016, team “Mucosal microbiota in chronic inflammatory diseases”, CNRS UMR 8104, Université Paris Cité, Paris, France
- INSERM U1306, Microbiome-Host Interaction group, Institut Pasteur, Université Paris Cité, Paris, France
| | - Benoit Chassaing
- INSERM U1016, team “Mucosal microbiota in chronic inflammatory diseases”, CNRS UMR 8104, Université Paris Cité, Paris, France
- INSERM U1306, Microbiome-Host Interaction group, Institut Pasteur, Université Paris Cité, Paris, France
| | - Andrew D. Patterson
- Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, PA, USA
| | - Vishal Singh
- Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA, USA
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13
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Ge X, Schut GJ, Tran J, Poole II FL, Niks D, Menjivar K, Hille R, Adams MWW. Characterization of the Membrane-Associated Electron-Bifurcating Flavoenzyme EtfABCX from the Hyperthermophilic Bacterium Thermotoga maritima. Biochemistry 2023; 62:3554-3567. [PMID: 38061393 PMCID: PMC10734219 DOI: 10.1021/acs.biochem.3c00473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 11/20/2023] [Accepted: 11/20/2023] [Indexed: 12/20/2023]
Abstract
Electron bifurcation is an energy-conservation mechanism in which a single enzyme couples an exergonic reaction with an endergonic one. Heterotetrameric EtfABCX drives the reduction of low-potential ferredoxin (E°' ∼ -450 mV) by oxidation of the midpotential NADH (E°' = -320 mV) by simultaneously coupling the reaction to reduction of the high-potential menaquinone (E°' = -74 mV). Electron bifurcation occurs at the NADH-oxidizing bifurcating-flavin adenine dinucleotide (BF-FAD) in EtfA, which has extremely crossed half-potentials and passes the first, high-potential electron to an electron-transferring FAD and via two iron-sulfur clusters eventually to menaquinone. The low-potential electron on the BF-FAD semiquinone simultaneously reduces ferredoxin. We have expressed the genes encodingThermotoga maritimaEtfABCX in E. coli and purified the EtfABCX holoenzyme and the EtfAB subcomplex. The bifurcation activity of EtfABCX was demonstrated by using electron paramagnetic resonance (EPR) to follow accumulation of reduced ferredoxin. To elucidate structural factors that impart the bifurcating ability, EPR and NADH titrations monitored by visible spectroscopy and dye-linked enzyme assays have been employed to characterize four conserved residues, R38, P239, and V242 in EtfA and R140 in EtfB, in the immediate vicinity of the BF-FAD. The R38, P239, and V242 variants showed diminished but still significant bifurcation activity. Despite still being partially reduced by NADH, the R140 variant had no bifurcation activity, and electron transfer to its two [4Fe-4S] clusters was prevented. The role of R140 is discussed in terms of the bifurcation mechanism in EtfABCX and in the other three families of bifurcating enzymes.
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Affiliation(s)
- Xiaoxuan Ge
- Department
of Biochemistry and Molecular Biology, University
of Georgia, Athens, Georgia 30602, United States
| | - Gerrit J. Schut
- Department
of Biochemistry and Molecular Biology, University
of Georgia, Athens, Georgia 30602, United States
| | - Jessica Tran
- Department
of Biochemistry, University of California,
Riverside, Riverside, California 92507, United States
| | - Farris L. Poole II
- Department
of Biochemistry and Molecular Biology, University
of Georgia, Athens, Georgia 30602, United States
| | - Dimitri Niks
- Department
of Biochemistry, University of California,
Riverside, Riverside, California 92507, United States
| | - Kevin Menjivar
- Department
of Biochemistry, University of California,
Riverside, Riverside, California 92507, United States
| | - Russ Hille
- Department
of Biochemistry, University of California,
Riverside, Riverside, California 92507, United States
| | - Michael W. W. Adams
- Department
of Biochemistry and Molecular Biology, University
of Georgia, Athens, Georgia 30602, United States
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14
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Re A. Translational efficiency in gas-fermenting bacteria: Adding a new layer of regulation to gene expression in acetogens. iScience 2023; 26:108383. [PMID: 38034355 PMCID: PMC10684804 DOI: 10.1016/j.isci.2023.108383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2023] Open
Abstract
Major advances in mastering metabolism of single carbon (C1) gaseous feedstocks in acetogenic microorganisms are primed to fuel the transition toward environmentally sustainable and cost-efficient production schemes of biofuels and value-added biochemicals. Since acetogens grow under autotrophic energy-limited conditions, protein synthesis is expected to be controlled. This survey integrated publicly available RNA sequencing and ribosome profiling studies of several acetogens, providing data on genome-scale transcriptional and translational responses of A. woodii, E. limosum, C. drakei, and C. ljungdahlii to autotrophic and heterotrophic growth conditions. The extent of translational efficiency turned out to vary across key functional modules in acetogens' metabolism. Translational control was confirmed to support stoichiometric protein production in multimeric complexes. Comparing the autotrophic to the heterotrophic growth condition revealed growth-dependent regulation of translational efficiency, pointing at translational buffering as a widespread phenomenon shared by acetogens.
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Affiliation(s)
- Angela Re
- Department of Applied Science and Technology, Politecnico di Torino, 10129 Torino, Italy
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15
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Jo SH, Jeon HJ, Song WS, Lee JS, Kwon JE, Park JH, Kim YR, Kim MG, Baek JH, Kwon SY, Kim JS, Yang YH, Kim YG. Unveiling the inhibition mechanism of Clostridioides difficile by Bifidobacterium longum via multiomics approach. Front Microbiol 2023; 14:1293149. [PMID: 38029200 PMCID: PMC10663266 DOI: 10.3389/fmicb.2023.1293149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 10/23/2023] [Indexed: 12/01/2023] Open
Abstract
Antibiotic-induced gut microbiota disruption constitutes a major risk factor for Clostridioides difficile infection (CDI). Further, antibiotic therapy, which is the standard treatment option for CDI, exacerbates gut microbiota imbalance, thereby causing high recurrent CDI incidence. Consequently, probiotic-based CDI treatment has emerged as a long-term management and preventive option. However, the mechanisms underlying the therapeutic effects of probiotics for CDI remain uninvestigated, thereby creating a knowledge gap that needs to be addressed. To fill this gap, we used a multiomics approach to holistically investigate the mechanisms underlying the therapeutic effects of probiotics for CDI at a molecular level. We first screened Bifidobacterium longum owing to its inhibitory effect on C. difficile growth, then observed the physiological changes associated with the inhibition of C. difficile growth and toxin production via a multiomics approach. Regarding the mechanism underlying C. difficile growth inhibition, we detected a decrease in intracellular adenosine triphosphate (ATP) synthesis due to B. longum-produced lactate and a subsequent decrease in (deoxy)ribonucleoside triphosphate synthesis. Via the differential regulation of proteins involved in translation and protein quality control, we identified B. longum-induced proteinaceous stress. Finally, we found that B. longum suppressed the toxin production of C. difficile by replenishing proline consumed by it. Overall, the findings of the present study expand our understanding of the mechanisms by which probiotics inhibit C. difficile growth and contribute to the development of live biotherapeutic products based on molecular mechanisms for treating CDI.
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Affiliation(s)
- Sung-Hyun Jo
- Department of Chemical Engineering, Soongsil University, Seoul, Republic of Korea
| | - Hyo-Jin Jeon
- Department of Chemical Engineering, Soongsil University, Seoul, Republic of Korea
| | - Won-Suk Song
- Department of Chemical Engineering, Soongsil University, Seoul, Republic of Korea
| | - Jae-Seung Lee
- Department of Chemical Engineering, Soongsil University, Seoul, Republic of Korea
| | - Ji-Eun Kwon
- Department of Chemical Engineering, Soongsil University, Seoul, Republic of Korea
| | - Ji-Hyeon Park
- Department of Chemical Engineering, Soongsil University, Seoul, Republic of Korea
| | - Ye-Rim Kim
- Department of Chemical Engineering, Soongsil University, Seoul, Republic of Korea
| | - Min-Gyu Kim
- Department of Chemical Engineering, Soongsil University, Seoul, Republic of Korea
| | - Ji-Hyun Baek
- Department of Chemical Engineering, Soongsil University, Seoul, Republic of Korea
| | - Seo-Young Kwon
- Department of Chemical Engineering, Soongsil University, Seoul, Republic of Korea
| | - Jae-Seok Kim
- Department of Laboratory Medicine, Kangdong Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Republic of Korea
| | - Yung-Hun Yang
- Department of Biological Engineering, College of Engineering, Konkuk University, Seoul, Republic of Korea
| | - Yun-Gon Kim
- Department of Chemical Engineering, Soongsil University, Seoul, Republic of Korea
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16
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Jin S, Chen X, Yang J, Ding J. Lactate dehydrogenase D is a general dehydrogenase for D-2-hydroxyacids and is associated with D-lactic acidosis. Nat Commun 2023; 14:6638. [PMID: 37863926 PMCID: PMC10589216 DOI: 10.1038/s41467-023-42456-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 10/11/2023] [Indexed: 10/22/2023] Open
Abstract
Mammalian lactate dehydrogenase D (LDHD) catalyzes the oxidation of D-lactate to pyruvate. LDHD mutations identified in patients with D-lactic acidosis lead to deficient LDHD activity. Here, we perform a systematic biochemical study of mouse LDHD (mLDHD) and determine the crystal structures of mLDHD in FAD-bound form and in complexes with FAD, Mn2+ and a series of substrates or products. We demonstrate that mLDHD is an Mn2+-dependent general dehydrogenase which exhibits catalytic activity for D-lactate and other D-2-hydroxyacids containing hydrophobic moieties, but no activity for their L-isomers or D-2-hydroxyacids containing hydrophilic moieties. The substrate-binding site contains a positively charged pocket to bind the common glycolate moiety and a hydrophobic pocket with some elasticity to bind the varied hydrophobic moieties of substrates. The structural and biochemical data together reveal the molecular basis for the substrate specificity and catalytic mechanism of LDHD, and the functional roles of mutations in the pathogenesis of D-lactic acidosis.
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Affiliation(s)
- Shan Jin
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai, 200031, China
| | - Xingchen Chen
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai, 200031, China
| | - Jun Yang
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai, 200031, China
| | - Jianping Ding
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai, 200031, China.
- School of Life Science and Technology, ShanghaiTech University, 393 Middle Huaxia Road, Shanghai, 201210, China.
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17
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Moon J, Schubert A, Poehlein A, Daniel R, Müller V. A new metabolic trait in an acetogen: Mixed acid fermentation of fructose in a methylene-tetrahydrofolate reductase mutant of Acetobacterium woodii. ENVIRONMENTAL MICROBIOLOGY REPORTS 2023; 15:339-351. [PMID: 37150590 PMCID: PMC10472528 DOI: 10.1111/1758-2229.13160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 04/20/2023] [Indexed: 05/09/2023]
Abstract
To inactivate the Wood-Ljungdahl pathway in the acetogenic model bacterium Acetobacterium woodii, the genes metVF encoding two of the subunits of the methylene-tetrahydrofolate reductase were deleted. As expected, the mutant did not grow on C1 compounds and also not on lactate, ethanol or butanediol. In contrast to a mutant in which the first enzyme of the pathway (hydrogen-dependent CO2 reductase) had been genetically deleted, cells were able to grow on fructose, albeit with lower rates and yields than the wild-type. Growth was restored by addition of an external electron sink, glycine betaine + CO2 or caffeate. Resting cells pre-grown on fructose plus an external electron acceptor fermented fructose to two acetate and four hydrogen, that is, performed hydrogenogenesis. Cells pre-grown under fermentative conditions on fructose alone redirected carbon and electrons to form lactate, formate, ethanol as well as hydrogen. Apparently, growth on fructose alone induced enzymes for mixed acid fermentation (MAF). Transcriptome analyses revealed enzymes potentially involved in MAF and a quantitative model for MAF from fructose in A. woodii is presented.
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Affiliation(s)
- Jimyung Moon
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular BiosciencesJohann Wolfgang Goethe UniversityFrankfurtGermany
| | - Anja Schubert
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular BiosciencesJohann Wolfgang Goethe UniversityFrankfurtGermany
| | - Anja Poehlein
- Göttingen Genomics Laboratory, Institute for Microbiology and GeneticsGeorg August UniversityGöttingenGermany
| | - Rolf Daniel
- Göttingen Genomics Laboratory, Institute for Microbiology and GeneticsGeorg August UniversityGöttingenGermany
| | - Volker Müller
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular BiosciencesJohann Wolfgang Goethe UniversityFrankfurtGermany
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18
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He Z, Liu R, Wang M, Wang Q, Zheng J, Ding J, Wen J, Fahey AG, Zhao G. Combined effect of microbially derived cecal SCFA and host genetics on feed efficiency in broiler chickens. MICROBIOME 2023; 11:198. [PMID: 37653442 PMCID: PMC10472625 DOI: 10.1186/s40168-023-01627-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 07/18/2023] [Indexed: 09/02/2023]
Abstract
BACKGROUND Improving feed efficiency is the most important goal for modern animal production. The regulatory mechanisms of controlling feed efficiency traits are extremely complex and include the functions related to host genetics and gut microbiota. Short-chain fatty acids (SCFAs), as significant metabolites of microbiota, could be used to refine the combined effect of host genetics and gut microbiota. However, the association of SCFAs with the gut microbiota and host genetics for regulating feed efficiency is far from understood. RESULTS In this study, 464 broilers were housed for RFI measuring and examining the host genome sequence. And 300 broilers were examined for cecal microbial data and SCFA concentration. Genome-wide association studies (GWAS) showed that four out of seven SCFAs had significant associations with genome variants. One locus (chr4: 29414391-29417189), located near or inside the genes MAML3, SETD7, and MGST2, was significantly associated with propionate and had a modest effect on feed efficiency traits and the microbiota. The genetic effect of the top SNP explained 8.43% variance of propionate. Individuals with genotype AA had significantly different propionate concentrations (0.074 vs. 0.131 μg/mg), feed efficiency (FCR: 1.658 vs. 1.685), and relative abundance of 14 taxa compared to those with the GG genotype. Christensenellaceae and Christensenellaceae_R-7_group were associated with feed efficiency, propionate concentration, the top SNP genotypes, and lipid metabolism. Individuals with a higher cecal abundance of these taxa showed better feed efficiency and lower concentrations of caecal SCFAs. CONCLUSION Our study provides strong evidence of the pathway that host genome variants affect the cecal SCFA by influencing caecal microbiota and then regulating feed efficiency. The cecal taxa Christensenellaceae and Christensenellaceae_R-7_group were identified as representative taxa contributing to the combined effect of host genetics and SCFAs on chicken feed efficiency. These findings provided strong evidence of the combined effect of host genetics and gut microbial SCFAs in regulating feed efficiency traits. Video Abstract.
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Affiliation(s)
- Zhengxiao He
- State Key Laboratory of Animal Nutrition; Key Laboratory of Animal (Poultry) Genetics Breeding and Reproduction, Ministry of Agriculture, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100193 China
- School of Agriculture and Food Science, University College Dublin, Dublin, Ireland
| | - Ranran Liu
- State Key Laboratory of Animal Nutrition; Key Laboratory of Animal (Poultry) Genetics Breeding and Reproduction, Ministry of Agriculture, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100193 China
| | - Mengjie Wang
- State Key Laboratory of Animal Nutrition; Key Laboratory of Animal (Poultry) Genetics Breeding and Reproduction, Ministry of Agriculture, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100193 China
| | - Qiao Wang
- State Key Laboratory of Animal Nutrition; Key Laboratory of Animal (Poultry) Genetics Breeding and Reproduction, Ministry of Agriculture, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100193 China
| | - Jumei Zheng
- State Key Laboratory of Animal Nutrition; Key Laboratory of Animal (Poultry) Genetics Breeding and Reproduction, Ministry of Agriculture, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100193 China
| | - Jiqiang Ding
- State Key Laboratory of Animal Nutrition; Key Laboratory of Animal (Poultry) Genetics Breeding and Reproduction, Ministry of Agriculture, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100193 China
| | - Jie Wen
- State Key Laboratory of Animal Nutrition; Key Laboratory of Animal (Poultry) Genetics Breeding and Reproduction, Ministry of Agriculture, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100193 China
| | - Alan G. Fahey
- School of Agriculture and Food Science, University College Dublin, Dublin, Ireland
| | - Guiping Zhao
- State Key Laboratory of Animal Nutrition; Key Laboratory of Animal (Poultry) Genetics Breeding and Reproduction, Ministry of Agriculture, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100193 China
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19
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Katsyv A, Essig M, Bedendi G, Sahin S, Milton RD, Müller V. Characterization of ferredoxins from the thermophilic, acetogenic bacterium Thermoanaerobacter kivui. FEBS J 2023; 290:4107-4125. [PMID: 37074156 DOI: 10.1111/febs.16801] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 03/21/2023] [Accepted: 04/19/2023] [Indexed: 04/20/2023]
Abstract
A major electron carrier involved in energy and carbon metabolism in the acetogenic model organism Thermoanaerobacter kivui is ferredoxin, an iron-sulfur-containing, electron-transferring protein. Here, we show that the genome of T. kivui encodes four putative ferredoxin-like proteins (TKV_c09620, TKV_c16450, TKV_c10420 and TKV_c19530). All four genes were cloned, a His-tag encoding sequence was added and the proteins were produced from a plasmid in T. kivui. The purified proteins had an absorption peak at 430 nm typical for ferredoxins. The determined iron-sulfur content is consistent with the presence of two predicted [4Fe4S] clusters in TKV_c09620 and TKV_c19530 or one predicted [4Fe4S] cluster in TKV_c16450 and TKV_c10420 respectively. The reduction potential (Em ) for TKV_c09620, TKV_c16450, TKV_c10420 and TKV_c19530 was determined to be -386 ± 4 mV, -386 ± 2 mV, -559 ± 10 mV and -557 ± 3 mV, respectively. TKV_c09620 and TKV_c16450 served as electron carriers for different oxidoreductases from T. kivui. Deletion of the ferredoxin genes led to only a slight reduction of growth on pyruvate or autotrophically on H2 + CO2 . Transcriptional analysis revealed that TKV_c09620 was upregulated in a ΔTKV_c16450 mutant and vice versa TKV_c16450 in a ΔTKV_c09620 mutant, indicating that TKV_c09620 and TKV_c16450 can replace each other. In sum, our data are consistent with the hypothesis that TKV_c09620 and TKV_c16450 are ferredoxins involved in autotrophic and heterotrophic metabolism of T. kivui.
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Affiliation(s)
- Alexander Katsyv
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University, Frankfurt am Main, Germany
| | - Melanie Essig
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University, Frankfurt am Main, Germany
| | - Giada Bedendi
- Department of Inorganic and Analytical Chemistry, University of Geneva, Geneva, Switzerland
| | - Selmihan Sahin
- Department of Inorganic and Analytical Chemistry, University of Geneva, Geneva, Switzerland
| | - Ross D Milton
- Department of Inorganic and Analytical Chemistry, University of Geneva, Geneva, Switzerland
| | - Volker Müller
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University, Frankfurt am Main, Germany
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20
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Moon J, Waschinger LM, Müller V. Lactate formation from fructose or C1 compounds in the acetogen Acetobacterium woodii by metabolic engineering. Appl Microbiol Biotechnol 2023:10.1007/s00253-023-12637-7. [PMID: 37417977 PMCID: PMC10390620 DOI: 10.1007/s00253-023-12637-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 06/12/2023] [Accepted: 06/15/2023] [Indexed: 07/08/2023]
Abstract
Anaerobic, acetogenic bacteria are promising biocatalysts for a sustainable bioeconomy since they capture and convert carbon dioxide to acetic acid. Hydrogen is an intermediate in acetate formation from organic as well as C1 substrates. Here, we analyzed mutants of the model acetogen Acetobacterium woodii in which either one of the two hydrogenases or both together were genetically deleted. In resting cells of the double mutant, hydrogen formation from fructose was completely abolished and carbon was redirected largely to lactate. The lactate/fructose and lactate/acetate ratios were 1.24 and 2.76, respectively. We then tested for lactate formation from methyl groups (derived from glycine betaine) and carbon monoxide. Indeed, also under these conditions lactate and acetate were formed in equimolar amounts with a lactate/acetate ratio of 1.13. When the electron-bifurcating lactate dehydrogenase/ETF complex was genetically deleted, lactate formation was completely abolished. These experiments demonstrate the capability of A. woodii to produce lactate from fructose but also from promising C1 substrates, methyl groups and carbon monoxide. This adds an important milestone towards generation of a value chain leading from CO2 to value-added compounds. KEY POINTS: • Resting cells of the ΔhydBA/hdcr mutant of Acetobacterium woodii produced lactate from fructose or methyl groups + CO • Lactate formation from methyl groups + CO was completely abolished after deletion of lctBCD • Metabolic engineering of a homoacetogen to lactate formation gives a potential for industrial applications.
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Affiliation(s)
- Jimyung Moon
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University, Max-von-Laue-Str. 9, D-60438, Frankfurt, Germany
| | - Lara M Waschinger
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University, Max-von-Laue-Str. 9, D-60438, Frankfurt, Germany
| | - Volker Müller
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University, Max-von-Laue-Str. 9, D-60438, Frankfurt, Germany.
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21
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Britton TA, Wu C, Chen YW, Franklin D, Chen Y, Camacho MI, Luong TT, Das A, Ton-That H. The respiratory enzyme complex Rnf is vital for metabolic adaptation and virulence in Fusobacterium nucleatum. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.13.544113. [PMID: 37398403 PMCID: PMC10312631 DOI: 10.1101/2023.06.13.544113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
A prominent oral commensal and opportunistic pathogen, Fusobacterium nucleatum can traverse to extra-oral sites such as placenta and colon, promoting adverse pregnancy outcomes and colorectal cancer, respectively. How this anaerobe sustains many metabolically changing environments enabling its virulence potential remains unclear. Informed by our genome-wide transposon mutagenesis, we report here that the highly conserved Rnf complex, encoded by the rnfCDGEAB gene cluster, is key to fusobacterial metabolic adaptation and virulence. Genetic disruption of the Rnf complex via non-polar, in-frame deletion of rnfC (Δ rnfC ) abrogates polymicrobial interaction (or coaggregation) associated with adhesin RadD and biofilm formation. The defect in coaggregation is not due to reduced cell surface of RadD, but rather an increased level of extracellular lysine, which binds RadD and inhibits coaggregation. Indeed, removal of extracellular lysine via washing Δ rnfC cells restores coaggregation, while addition of lysine inhibits this process. These phenotypes mirror that of a mutant (Δ kamAΔ ) that fails to metabolize extracellular lysine. Strikingly, the Δ rnfC mutant is defective in ATP production, cell growth, cell morphology, and expression of the enzyme MegL that produces hydrogen sulfide from cysteine. Targeted metabolic profiling demonstrated that catabolism of many amino acids, including histidine and lysine, is altered in Δ rnfC cells, thereby reducing production of ATP and metabolites including H2S and butyrate. Most importantly, we show that the Δ rnfC mutant is severely attenuated in a mouse model of preterm birth. The indispensable function of Rnf complex in fusobacterial pathogenesis via modulation of bacterial metabolism makes it an attractive target for developing therapeutic intervention.
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22
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Feregrino-Mondragón RD, Santiago-Martínez MG, Silva-Flores M, Encalada R, Reyes-Prieto A, Rodríguez-Zavala JS, Peña-Ocaña BA, Moreno-Sánchez R, Saavedra E, Jasso-Chávez R. Lactate oxidation is linked to energy conservation and to oxygen detoxification via a putative terminal cytochrome oxidase in Methanosarcina acetivorans. Arch Biochem Biophys 2023:109667. [PMID: 37327962 DOI: 10.1016/j.abb.2023.109667] [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: 12/27/2022] [Revised: 06/09/2023] [Accepted: 06/11/2023] [Indexed: 06/18/2023]
Abstract
The marine archaeon Methanosarcina acetivorans contains a putative NAD + -independent d-lactate dehydrogenase (D-iLDH/glycolate oxidase) encoded by the MA4631 gene, belonging to the FAD-oxidase C superfamily. Nucleotide sequences similar to MA4631 gene, were identified in other methanogens and Firmicutes with >90 and 35-40% identity, respectively. Therefore, the lactate metabolism in M. acetivorans is reported here. Cells subjected to intermittent pulses of oxygen (air-adapted; AA-Ma cells) consumed lactate only in combination with acetate, increasing methane production and biomass yield. In AA-Ma cells incubated with d-lactate plus [14C]-l-lactate, the radioactive label was found in methane, CO2 and glycogen, indicating that lactate metabolism fed both methanogenesis and gluconeogenesis. Moreover, d-lactate oxidation was coupled to O2-consumption which was sensitive to HQNO; also, AA-Ma cells showed high transcript levels of gene dld and those encoding subunits A (MA1006) and B (MA1007) of a putative cytochrome bd quinol oxidase, compared to anaerobic control cells. An E. coli mutant deficient in dld complemented with the MA4631 gene, grew with d-lactate as carbon source and showed membrane-bound d-lactate:quinone oxidoreductase activity. The product of the MA4631 gene is a FAD-containing monomer showing activity of iLDH with preference to d-lactate. The results suggested that air adapted M. acetivorans is able to co-metabolize lactate and acetate with associated oxygen consumption by triggering the transcription and synthesis of the D-iLDH and a putative cytochrome bd: methanophenazine (quinol) oxidoreductase. Biomass generation and O2 consumption, suggest a potentially new oxygen detoxification mechanism coupled to energy conservation in this methanogen.
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Affiliation(s)
| | - Michel Geovanni Santiago-Martínez
- Departamento de Bioquímica, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, 14080, Mexico; Department of Molecular and Cell Biology, The University of Connecticut, Storrs, 06269, Connecticut, USA
| | - Mayel Silva-Flores
- Departamento de Bioquímica, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, 14080, Mexico
| | - Rusely Encalada
- Departamento de Bioquímica, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, 14080, Mexico
| | - Adrián Reyes-Prieto
- Department of Biology, University of New Brunswick, Fredericton, New Brunswick, Canada
| | - José S Rodríguez-Zavala
- Departamento de Bioquímica, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, 14080, Mexico
| | - Betsy Anaid Peña-Ocaña
- Departamento de Bioquímica, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, 14080, Mexico
| | - Rafael Moreno-Sánchez
- Departamento de Bioquímica, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, 14080, Mexico
| | - Emma Saavedra
- Departamento de Bioquímica, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, 14080, Mexico
| | - Ricardo Jasso-Chávez
- Departamento de Bioquímica, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, 14080, Mexico.
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23
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Walters KA, Mohan G, Myers KS, Ingle AT, Donohue TJ, Noguera DR. A metagenome-level analysis of a microbial community fermenting ultra-filtered milk permeate. Front Bioeng Biotechnol 2023; 11:1173656. [PMID: 37324413 PMCID: PMC10263058 DOI: 10.3389/fbioe.2023.1173656] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 05/03/2023] [Indexed: 06/17/2023] Open
Abstract
Fermentative microbial communities have the potential to serve as biocatalysts for the conversion of low-value dairy coproducts into renewable chemicals, contributing to a more sustainable global economy. To develop predictive tools for the design and operation of industrially relevant strategies that utilize fermentative microbial communities, there is a need to determine the genomic features of community members that are characteristic to the accumulation of different products. To address this knowledge gap, we performed a 282-day bioreactor experiment with a microbial community that was fed ultra-filtered milk permeate, a low-value coproduct from the dairy industry. The bioreactor was inoculated with a microbial community from an acid-phase digester. A metagenomic analysis was used to assess microbial community dynamics, construct metagenome-assembled genomes (MAGs), and evaluate the potential for lactose utilization and fermentation product synthesis of community members represented by the assembled MAGs. This analysis led us to propose that, in this reactor, members of the Actinobacteriota phylum are important in the degradation of lactose, via the Leloir pathway and the bifid shunt, and the production of acetic, lactic, and succinic acids. In addition, members of the Firmicutes phylum contribute to the chain-elongation-mediated production of butyric, hexanoic, and octanoic acids, with different microbes using either lactose, ethanol, or lactic acid as the growth substrate. We conclude that genes encoding carbohydrate utilization pathways, and genes encoding lactic acid transport into the cell, electron confurcating lactate dehydrogenase, and its associated electron transfer flavoproteins, are genomic features whose presence in Firmicutes needs to be established to infer the growth substrate used for chain elongation.
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Affiliation(s)
- Kevin A. Walters
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, United States
- Wisconsin Energy Institute, University of Wisconsin-Madison, Madison, WI, United States
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, United States
| | - Geethaanjali Mohan
- Wisconsin Energy Institute, University of Wisconsin-Madison, Madison, WI, United States
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, United States
| | - Kevin S. Myers
- Wisconsin Energy Institute, University of Wisconsin-Madison, Madison, WI, United States
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, United States
| | - Abel T. Ingle
- Wisconsin Energy Institute, University of Wisconsin-Madison, Madison, WI, United States
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, United States
- Department of Civil and Environmental Engineering, University of Wisconsin-Madison, Madison, WI, United States
| | - Timothy J. Donohue
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, United States
- Wisconsin Energy Institute, University of Wisconsin-Madison, Madison, WI, United States
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, United States
| | - Daniel R. Noguera
- Wisconsin Energy Institute, University of Wisconsin-Madison, Madison, WI, United States
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, United States
- Department of Civil and Environmental Engineering, University of Wisconsin-Madison, Madison, WI, United States
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24
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Abstract
Microbial communities are shaped by positive and negative interactions ranging from competition to mutualism. In the context of the mammalian gut and its microbial inhabitants, the integrated output of the community has important impacts on host health. Cross-feeding, the sharing of metabolites between different microbes, has emergent roles in establishing communities of gut commensals that are stable, resistant to invasion, and resilient to external perturbation. In this review, we first explore the ecological and evolutionary implications of cross-feeding as a cooperative interaction. We then survey mechanisms of cross-feeding across trophic levels, from primary fermenters to H2 consumers that scavenge the final metabolic outputs of the trophic network. We extend this analysis to also include amino acid, vitamin, and cofactor cross-feeding. Throughout, we highlight evidence for the impact of these interactions on each species' fitness as well as host health. Understanding cross-feeding illuminates an important aspect of microbe-microbe and host-microbe interactions that establishes and shapes our gut communities.
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Affiliation(s)
- Elizabeth J Culp
- Department of Microbial Pathogenesis and Microbial Sciences Institute, Yale University School of Medicine, New Haven, CT, USA
| | - Andrew L Goodman
- Department of Microbial Pathogenesis and Microbial Sciences Institute, Yale University School of Medicine, New Haven, CT, USA.
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25
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Kronen M, Vázquez-Campos X, Wilkins MR, Lee M, Manefield MJ. Evidence for a Putative Isoprene Reductase in Acetobacterium wieringae. mSystems 2023; 8:e0011923. [PMID: 36943133 PMCID: PMC10134865 DOI: 10.1128/msystems.00119-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2023] Open
Abstract
Recent discoveries of isoprene-metabolizing microorganisms suggest they might play an important role in the global isoprene budget. Under anoxic conditions, isoprene can be used as an electron acceptor and is reduced to methylbutene. This study describes the proteogenomic profiling of an isoprene-reducing bacterial culture to identify organisms and genes responsible for the isoprene hydrogenation reaction. A metagenome-assembled genome (MAG) of the most abundant (89% relative abundance) lineage in the enrichment, Acetobacterium wieringae, was obtained. Comparative proteogenomics and reverse transcription-PCR (RT-PCR) identified a putative five-gene operon from the A. wieringae MAG upregulated during isoprene reduction. The operon encodes a putative oxidoreductase, three pleiotropic nickel chaperones (2 × HypA, HypB), and one 4Fe-4S ferredoxin. The oxidoreductase is proposed as the putative isoprene reductase with a binding site for NADH, flavin adenine dinucleotide (FAD), two pairs of canonical [4Fe-4S] clusters, and a putative iron-sulfur cluster site in a Cys6-bonding environment. Well-studied Acetobacterium strains, such as A. woodii DSM 1030, A. wieringae DSM 1911, or A. malicum DSM 4132, do not encode the isoprene-regulated operon but encode, like many other bacteria, a homolog of the putative isoprene reductase (~47 to 49% amino acid sequence identity). Uncharacterized homologs of the putative isoprene reductase are observed across the Firmicutes, Spirochaetes, Tenericutes, Actinobacteria, Chloroflexi, Bacteroidetes, and Proteobacteria, suggesting the ability of biohydrogenation of unfunctionalized conjugated doubled bonds in other unsaturated hydrocarbons. IMPORTANCE Isoprene was recently shown to act as an electron acceptor for a homoacetogenic bacterium. The focus of this study is the molecular basis for isoprene reduction. By comparing a genome from our isoprene-reducing enrichment culture, dominated by Acetobacterium wieringae, with genomes of other Acetobacterium lineages that do not reduce isoprene, we shortlisted candidate genes for isoprene reduction. Using comparative proteogenomics and reverse transcription-PCR we have identified a putative five-gene operon encoding an oxidoreductase referred to as putative isoprene reductase.
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Affiliation(s)
- Miriam Kronen
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, Australia
| | - Xabier Vázquez-Campos
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Marc R Wilkins
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Matthew Lee
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, Australia
| | - Michael J Manefield
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, Australia
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26
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Firkins JL, Mitchell KE. Invited review: Rumen modifiers in today's dairy rations. J Dairy Sci 2023; 106:3053-3071. [PMID: 36935236 DOI: 10.3168/jds.2022-22644] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 11/23/2022] [Indexed: 03/19/2023]
Abstract
Our aim was to review feed additives that have a potential ruminal mechanism of action when fed to dairy cattle. We discuss how additives can influence ruminal fermentation stoichiometry through electron transfer mechanisms, particularly the production and usage of dihydrogen. Lactate accumulation should be avoided, especially when acidogenic conditions suppress ruminal neutral detergent fiber digestibility or lead to subclinical acidosis. Yeast products and other probiotics are purported to influence lactate uptake, but growing evidence also supports that yeast products influence expression of gut epithelial genes promoting barrier function and resulting inflammatory responses by the host to various stresses. We also have summarized methane-suppressing additives for potential usage in dairy rations. We focused on those with potential to decrease methane production without decreasing fiber digestibility or milk production. We identified some mitigating factors that need to be addressed more fully in future research. Growth factors such as branched-chain volatile fatty acids also are part of crucial cross-feeding among groups of microbes, particularly to optimize fiber digestibility in the rumen. Our developments of mechanisms of action for various rumen-active modifiers should help nutrition advisors anticipate when a benefit in field conditions is more likely.
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Affiliation(s)
- J L Firkins
- Department of Animal Sciences, The Ohio State University, Columbus 43210.
| | - K E Mitchell
- Department of Animal Sciences, The Ohio State University, Columbus 43210
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27
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Yang Z, Zeng X, Zhao Y, Chen R. AlphaFold2 and its applications in the fields of biology and medicine. Signal Transduct Target Ther 2023; 8:115. [PMID: 36918529 PMCID: PMC10011802 DOI: 10.1038/s41392-023-01381-z] [Citation(s) in RCA: 78] [Impact Index Per Article: 78.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Revised: 12/27/2022] [Accepted: 02/16/2023] [Indexed: 03/16/2023] Open
Abstract
AlphaFold2 (AF2) is an artificial intelligence (AI) system developed by DeepMind that can predict three-dimensional (3D) structures of proteins from amino acid sequences with atomic-level accuracy. Protein structure prediction is one of the most challenging problems in computational biology and chemistry, and has puzzled scientists for 50 years. The advent of AF2 presents an unprecedented progress in protein structure prediction and has attracted much attention. Subsequent release of structures of more than 200 million proteins predicted by AF2 further aroused great enthusiasm in the science community, especially in the fields of biology and medicine. AF2 is thought to have a significant impact on structural biology and research areas that need protein structure information, such as drug discovery, protein design, prediction of protein function, et al. Though the time is not long since AF2 was developed, there are already quite a few application studies of AF2 in the fields of biology and medicine, with many of them having preliminarily proved the potential of AF2. To better understand AF2 and promote its applications, we will in this article summarize the principle and system architecture of AF2 as well as the recipe of its success, and particularly focus on reviewing its applications in the fields of biology and medicine. Limitations of current AF2 prediction will also be discussed.
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Affiliation(s)
- Zhenyu Yang
- West China Biomedical Big Data Center, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Xiaoxi Zeng
- West China Biomedical Big Data Center, West China Hospital, Sichuan University, Chengdu, 610041, China.
| | - Yi Zhao
- West China Biomedical Big Data Center, West China Hospital, Sichuan University, Chengdu, 610041, China.
- Key Laboratory of Intelligent Information Processing, Advanced Computer Research Center, Institute of Computing Technology, Chinese Academy of Sciences, Beijing, 100190, China.
| | - Runsheng Chen
- West China Biomedical Big Data Center, West China Hospital, Sichuan University, Chengdu, 610041, China.
- Key Laboratory of RNA Biology, Center for Big Data Research in Health, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.
- Pingshan Translational Medicine Center, Shenzhen Bay Laboratory, Shenzhen, 518118, China.
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28
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New Insights into the Physiology of the Propionate Producers Anaerotignum propionicum and Anaerotignum neopropionicum (Formerly Clostridium propionicum and Clostridium neopropionicum). Microorganisms 2023; 11:microorganisms11030685. [PMID: 36985257 PMCID: PMC10053330 DOI: 10.3390/microorganisms11030685] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 02/23/2023] [Accepted: 03/03/2023] [Indexed: 03/10/2023] Open
Abstract
Propionate is an important platform chemical that is available through petrochemical synthesis. Bacterial propionate formation is considered an alternative, as bacteria can convert waste substrates into valuable products. In this regard, research primarily focused on propionibacteria due to high propionate titers achieved from different substrates. Whether other bacteria could also be attractive producers is unclear, mostly because little is known about these strains. Therefore, two thus far less researched strains, Anaerotignum propionicum and Anaerotignum neopropionicum, were investigated with regard to their morphologic and metabolic features. Microscopic analyses revealed a negative Gram reaction despite a Gram-positive cell wall as well as surface layers for both strains. Furthermore, growth, product profiles, and the potential for propionate formation from sustainable substrates, i.e., ethanol or lignocellulosic sugars, were assessed. Results showed that both strains can oxidize ethanol to different extents. While A. propionicum only partially used ethanol, A. neopropionicum converted 28.3 mM ethanol to 16.4 mM propionate. Additionally, the ability of A. neopropionicum to produce propionate from lignocellulose-derived substrates was analyzed, leading to propionate concentrations of up to 14.5 mM. Overall, this work provides new insights into the physiology of the Anaerotignum strains, which can be used to develop effective propionate producer strains.
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29
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Jin H, Huo L, Yang Y, Lv Y, Wang J, Maillard J, Holliger C, Löffler FE, Yan J. Sulfurospirillum diekertiae sp. nov., a tetrachloroethene-respiring bacterium isolated from contaminated soil. Int J Syst Evol Microbiol 2023; 73. [PMID: 36735579 DOI: 10.1099/ijsem.0.005693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Two anaerobic, tetrachloroethene- (PCE-) respiring bacterial isolates, designated strain ACSDCE
T and strain ACSTCE, were characterized using a polyphasic approach. Cells were Gram-stain-negative, motile, non-spore-forming and shared a vibrioid- to spirillum-shaped morphology. Optimum growth occurred at 30 °C and 0.1–0.4 % salinity. The pH range for growth was pH 5.5–7.5, with an optimum at pH 7.2. Hydrogen, formate, pyruvate and lactate as electron donors supported respiratory reductive dechlorination of PCE to cis-1,2-dichloroethene (cDCE) in strain ACSDCE
T and of PCE to trichloroethene (TCE) in strain ACSTCE. Both strains were able to grow with pyruvate under microaerobic conditions. Nitrate, elemental sulphur, and thiosulphate were alternative electron acceptors. Autotrophic growth was not observed and acetate served as carbon source for both strains. The major cellular fatty acids were C16 : 1
ω7c, C16 : 0, C14 : 0 and C18 : 1
ω7c. Both genomes feature a circular plasmid. Strains ACSDCE
T and ACSTCE were previously assigned to the candidate species 'Sulfurospirillum acididehalogenans'. Here, based on key genomic features and pairwise comparisons of whole-genome sequences, including average nucleotide identity, digital DNA–DNA hybridization and average amino acid identity, strains ACSDCE
T and ACSTCE, 'Ca. Sulfurospirillum diekertiae' strains SL2-1 and SL2-2, and the unclassified
Sulfurospirillum
sp. strain SPD-1 are grouped into one distinct species separate from previously described
Sulfurospirillum
species. Compared to
Sulfurospirillum multivorans
and
Sulfurospirillum halorespirans
, which dechlorinate PCE to cDCE without substantial TCE accumulation, these five strains produce TCE or cDCE as the end product. In addition, some cellular fatty acids (e.g., C16 : 0 3OH, C17 : 0 iso 3OH, C17 : 0 2OH) were detected in strains ACSDCE
T and ACSTCE but not in other
Sulfurospirillum
species. On the basis of phylogenetic, physiological and phenotypic characteristics, 'Ca. Sulfurospirillum acididehalogenans' and 'Ca. Sulfurospirillum diekertiae' are proposed to be merged into one novel species within the genus
Sulfurospirillum
, for which the name
Sulfurospirillum diekertiae
sp. nov. is proposed. The type strain is ACSDCE
T (=JCM 33349T= KCTC 15819T=CGMCC 1.5292T).
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Affiliation(s)
- Huijuan Jin
- Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, Liaoning 110016, PR China
- University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Leitao Huo
- Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, Liaoning 110016, PR China
- University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Yi Yang
- Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, Liaoning 110016, PR China
| | - Yan Lv
- Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, Liaoning 110016, PR China
- University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Jingjing Wang
- Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, Liaoning 110016, PR China
| | - Julien Maillard
- Ecole Polytechnique Fédérale de Lausanne (EPFL), School of Architecture, Civil and Environmental Engineering, Laboratory for Environmental Biotechnology, Station 6, CH-1015 Lausanne, Switzerland
| | - Christof Holliger
- Ecole Polytechnique Fédérale de Lausanne (EPFL), School of Architecture, Civil and Environmental Engineering, Laboratory for Environmental Biotechnology, Station 6, CH-1015 Lausanne, Switzerland
| | - Frank E Löffler
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee 37996, USA
- Center for Environmental Biotechnology, University of Tennessee, Knoxville, Tennessee 37996, USA
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
- Department of Civil and Environmental Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA
- Department of Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Jun Yan
- Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, Liaoning 110016, PR China
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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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Bioinformatics and metabolic flux analysis highlight a new mechanism involved in lactate oxidation in Clostridium tyrobutyricum. INTERNATIONAL MICROBIOLOGY : THE OFFICIAL JOURNAL OF THE SPANISH SOCIETY FOR MICROBIOLOGY 2023:10.1007/s10123-022-00316-y. [PMID: 36609955 PMCID: PMC10397141 DOI: 10.1007/s10123-022-00316-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2022] [Revised: 12/04/2022] [Accepted: 12/20/2022] [Indexed: 01/09/2023]
Abstract
Climate change and environmental issues compel us to find alternatives to the production of molecules of interest from petrochemistry. This study aims at understanding the production of butyrate, hydrogen, and CO2 from the oxidation of lactate with acetate in Clostridium tyrobutyricum and thus proposes an alternative carbon source to glucose. This specie is known to produce more butyrate than the other butyrate-producing clostridia species due to a lack of solvent genesis phase. The recent discoveries on flavin-based electron bifurcation and confurcation mechanism as a mode of energy conservation led us to suggest a new metabolic scheme for the formation of butyrate from lactate-acetate co-metabolism. While searching for genes encoding for EtfAB complexes and neighboring genes in the genome of C. tyrobutyricum, we identified a cluster of genes involved in butyrate formation and another cluster involved in lactate oxidation homologous to Acetobacterium woodii. A phylogenetic approach encompassing other butyrate-producing and/or lactate-oxidizing species based on EtfAB complexes confirmed these results. A metabolic scheme on the production of butyrate, hydrogen, and CO2 from the lactate-acetate co-metabolism in C. tyrobutyricum was constructed and then confirmed with data of steady-state continuous culture. This in silico metabolic carbon flux analysis model showed the coherence of the scheme from the carbon recovery, the cofactor ratio, and the ATP yield. This study improves our understanding of the lactate oxidation metabolic pathways and the role of acetate and intracellular redox balance, and paves the way for the production of molecules of interest as butyrate and hydrogen with C. tyrobutyricum.
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Acosta-Grinok M, Vázquez S, Guiliani N, Marín S, Demergasso C. Looking for the mechanism of arsenate respiration of Fusibacter sp. strain 3D3, independent of ArrAB. Front Microbiol 2022; 13:1029886. [PMID: 36532432 PMCID: PMC9751042 DOI: 10.3389/fmicb.2022.1029886] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Accepted: 11/08/2022] [Indexed: 12/02/2022] Open
Abstract
The literature has reported the isolation of arsenate-dependent growing microorganisms which lack a canonical homolog for respiratory arsenate reductase, ArrAB. We recently isolated an arsenate-dependent growing bacterium from volcanic arsenic-bearing environments in Northern Chile, Fusibacter sp. strain 3D3 (Fas) and studied the arsenic metabolism in this Gram-positive isolate. Features of Fas deduced from genome analysis and comparative analysis with other arsenate-reducing microorganisms revealed the lack of ArrAB coding genes and the occurrence of two arsC genes encoding for putative cytoplasmic arsenate reductases named ArsC-1 and ArsC-2. Interestingly, ArsC-1 and ArsC-2 belong to the thioredoxin-coupled family (because of the redox-active disulfide protein used as reductant), but they conferred differential arsenate resistance to the E. coli WC3110 ΔarsC strain. PCR experiments confirmed the absence of arrAB genes and results obtained using uncouplers revealed that Fas growth is linked to the proton gradient. In addition, Fas harbors ferredoxin-NAD+ oxidoreductase (Rnf) and electron transfer flavoprotein (etf) coding genes. These are key molecular markers of a recently discovered flavin-based electron bifurcation mechanism involved in energy conservation, mainly in anaerobic metabolisms regulated by the cellular redox state and mostly associated with cytoplasmic enzyme complexes. At least three electron-bifurcating flavoenzyme complexes were evidenced in Fas, some of them shared in conserved genomic regions by other members of the Fusibacter genus. These physiological and genomic findings permit us to hypothesize the existence of an uncharacterized arsenate-dependent growth metabolism regulated by the cellular redox state in the Fusibacter genus.
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Affiliation(s)
| | - Susana Vázquez
- Cátedra de Biotecnología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina,Instituto de Nanobiotecnología (NANOBIOTEC), Universidad de Buenos Aires (UBA) - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Nicolás Guiliani
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Antofagasta, Chile
| | - Sabrina Marín
- Biotechnology Center, Universidad Católica del Norte, Antofagasta, Chile
| | - Cecilia Demergasso
- Biotechnology Center, Universidad Católica del Norte, Antofagasta, Chile,Nucleus for the Study of Cancer at a Basic, Applied, and Clinical Level, Universidad Católica del Norte, Antofagasta, Chile,*Correspondence: Cecilia Demergasso,
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Simultaneous Production of Biohydrogen (bioH2) and Poly-Hydroxy-Alkanoates (PHAs) by a Photoheterotrophic Consortium Bioaugmented with Syntrophomonas wolfei. FERMENTATION-BASEL 2022. [DOI: 10.3390/fermentation8110644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Mixed cultures represent better alternatives to ferment organic waste and dark fermentation products in anerobic conditions because the microbial associations contribute to electron transfer mechanisms and combine metabolic possibilities. The understanding of the microbial interactions in natural and synthetic consortia and the strategies to improve the performance of the processes by bioaugmentation provide insight into the physiology and ecology of the mixed cultures used for biotechnological purposes. Here, synthetic microbial communities were built from three hydrogen (bioH2) and poly-hydroxy-alkanoates (PHA) producers, Clostridium pasteurianum, Rhodopseudomonas palustris and Syntrophomonas wolfei, and a photoheterotrophic mixed consortium C4, and their performance was evaluated during photofermentation. Higher hydrogen volumetric production rates (H2VPR) were determined with the consortia (28–40 mL/Lh) as compared with individual strains (20–27 mL/Lh). The designed consortia reached the highest bioH2 and PHA productions of 44.3 mmol and 50.46% and produced both metabolites simultaneously using dark fermentation effluents composed of a mixture of lactic, butyric, acetic, and propionic acids. When the mixed culture C4 was bioaugmented with S. wolfei, the bioH2 and PHA production reached 32 mmol and 50%, respectively. Overall, the consumption of organic acids was above 50%, which accounted up to 55% of total chemical oxygen demand (COD) removed. Increased bioH2 was observed in the condition when S. wolfei was added as the bioaugmentation agent, reaching up to 562 mL of H2 produced per gram of COD. The enhanced production of bioH2 and PHA can be explained by the metabolic interaction between the three selected strains, which likely include thermodynamic equilibrium, the assimilation of organic acids via beta-oxidation, and the production of bioH2 using a proton driving force derived from reduced menaquinone or via electron bifurcation.
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Revealing the Characteristics of Glucose- and Lactate-Based Chain Elongation for Caproate Production by Caproicibacterium lactatifermentans through Transcriptomic, Bioenergetic, and Regulatory Analyses. mSystems 2022; 7:e0053422. [PMID: 36073803 PMCID: PMC9600882 DOI: 10.1128/msystems.00534-22] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Caproate, an important medium-chain fatty acid, can only be synthesized by limited bacterial species by using ethanol, lactate, or certain saccharides. Caproicibacterium lactatifermentans is a promising caproate producer due to its glucose and lactate utilization capabilities. However, the global cellular responses of this bacterium to different carbon sources were not well understood. Here, C. lactatifermentans showed robust growth on glucose but more active caproate synthesis on lactate. Comparative transcriptome revealed that the genes involved in reverse β-oxidation for caproate synthesis and V-type ATPase-dependent ATP generation were upregulated under lactate condition, while several genes responsible for biomass synthesis were upregulated under glucose condition. Based on metabolic pathway reconstructions and bioenergetics analysis, the biomass accumulation on glucose condition may be supported by sufficient supplies of ATP and metabolite intermediates via glycolysis. In contrast, the ATP yield per glucose equivalent from lactate conversion into caproate was only 20% of that from glucose. Thus, the upregulation of the reverse β-oxidation genes may be essential for cell survival under lactate conditions. Furthermore, the remarkably decreased lactate utilization was observed after glucose acclimatization, indicating the negative modulation of lactate utilization by glucose metabolism. Based on the cotranscription of the lactate utilization repressor gene lldR with sugar-specific PTS genes and the opposite expression patterns of lldR and lactate utilization genes, a novel regulatory mechanism of glucose-repressed lactate utilization mediated via lldR was proposed. The results of this study suggested the molecular mechanism underlying differential physiologic and metabolic characteristics of C. lactatifermentans grown on glucose and lactate. IMPORTANCE Caproicibacterium lactatifermentans is a unique and robust caproate-producing bacterium in the family Oscillospiraceae due to its lactate utilization capability, whereas its close relatives such as Caproicibacterium amylolyticum, Caproiciproducens galactitolivorans, and Caproicibacter fermentans cannot utilize lactate but produce lactate as the main fermentation end product. Moreover, C. lactatifermentans can also utilize several saccharides such as glucose and maltose. Although the metabolic versatility of the bacterium makes it to be a promising industrial caproate producer, the cellular responses of C. lactatifermentans to different carbon sources were unknown. Here, the molecular mechanisms of biomass synthesis supported by glucose utilization and the cell survival supported by lactate utilization were revealed. A novel insight into the regulatory machinery in which glucose negatively regulates lactate utilization was proposed. This study provides a valuable basis to control and optimize caproate production, which will contribute to achieving a circular economy and environmental sustainability.
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Meier AB, Oppermann S, Drake HL, Schmidt O. The root zone of graminoids: A niche for H2-consuming acetogens in a minerotrophic peatland. Front Microbiol 2022; 13:978296. [PMID: 35992704 PMCID: PMC9391049 DOI: 10.3389/fmicb.2022.978296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Accepted: 07/19/2022] [Indexed: 11/13/2022] Open
Abstract
The importance of acetogens for H2 turnover and overall anaerobic degradation in peatlands remains elusive. In the well-studied minerotrophic peatland fen Schlöppnerbrunnen, H2-consuming acetogens are conceptualized to be largely outcompeted by iron reducers, sulfate reducers, and hydrogenotrophic methanogens in bulk peat soil. However, in root zones of graminoids, fermenters thriving on rhizodeposits and root litter might temporarily provide sufficient H2 for acetogens. In the present study, root-free peat soils from around the roots of Molinia caerulea and Carex rostrata (i.e., two graminoids common in fen Schlöpnnerbrunnen) were anoxically incubated with or without supplemental H2 to simulate conditions of high and low H2 availability in the fen. In unsupplemented soil treatments, H2 concentrations were largely below the detection limit (∼10 ppmV) and possibly too low for acetogens and methanogens, an assumption supported by the finding that neither acetate nor methane substantially accumulated. In the presence of supplemental H2, acetate accumulation exceeded CH4 accumulation in Molinia soil whereas acetate and methane accumulated equally in Carex soil. However, reductant recoveries indicated that initially, additional unknown processes were involved either in H2 consumption or the consumption of acetate produced by H2-consuming acetogens. 16S rRNA and 16S rRNA gene analyses revealed that potential acetogens (Clostridium, Holophagaceae), methanogens (Methanocellales, Methanobacterium), iron reducers (Geobacter), and physiologically uncharacterized phylotypes (Acidobacteria, Actinobacteria, Bacteroidetes) were stimulated by supplemental H2 in soil treatments. Phylotypes closely related to clostridial acetogens were also active in soil-free Molinia and Carex root treatments with or without supplemental H2. Due to pronounced fermentation activities, H2 consumption was less obvious in root treatments, and acetogens likely thrived on root organic carbon and fermentation products (e.g., ethanol) in addition to H2. Collectively, the data highlighted that in fen Schlöppnerbrunnen, acetogens are associated to graminoid roots and inhabit the peat soil around the roots, where they have to compete for H2 with methanogens and iron reducers. Furthermore, the study underscored that the metabolically flexible acetogens do not rely on H2, potentially a key advantage over other H2 consumers under the highly dynamic conditions characteristic for the root-zones of graminoids in peatlands.
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Affiliation(s)
- Anja B. Meier
- Department of Ecological Microbiology, University of Bayreuth, Bayreuth, Germany
| | - Sindy Oppermann
- Department of Ecological Microbiology, University of Bayreuth, Bayreuth, Germany
| | - Harold L. Drake
- Department of Ecological Microbiology, University of Bayreuth, Bayreuth, Germany
| | - Oliver Schmidt
- Department of Ecological Microbiology, University of Bayreuth, Bayreuth, Germany
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø, Norway
- *Correspondence: Oliver Schmidt,
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Schut GJ, Haja DK, Feng X, Poole FL, Li H, Adams MWW. An Abundant and Diverse New Family of Electron Bifurcating Enzymes With a Non-canonical Catalytic Mechanism. Front Microbiol 2022; 13:946711. [PMID: 35875533 PMCID: PMC9304861 DOI: 10.3389/fmicb.2022.946711] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 06/15/2022] [Indexed: 11/13/2022] Open
Abstract
Microorganisms utilize electron bifurcating enzymes in metabolic pathways to carry out thermodynamically unfavorable reactions. Bifurcating FeFe-hydrogenases (HydABC) reversibly oxidize NADH (E′∼−280 mV, under physiological conditions) and reduce protons to H2 gas (E°′−414 mV) by coupling this endergonic reaction to the exergonic reduction of protons by reduced ferredoxin (Fd) (E′∼−500 mV). We show here that HydABC homologs are surprisingly ubiquitous in the microbial world and are represented by 57 phylogenetically distinct clades but only about half are FeFe-hydrogenases. The others have replaced the hydrogenase domain with another oxidoreductase domain or they contain additional subunits, both of which enable various third reactions to be reversibly coupled to NAD+ and Fd reduction. We hypothesize that all of these enzymes carry out electron bifurcation and that their third substrates can include hydrogen peroxide, pyruvate, carbon monoxide, aldehydes, aryl-CoA thioesters, NADP+, cofactor F420, formate, and quinones, as well as many yet to be discovered. Some of the enzymes are proposed to be integral membrane-bound proton-translocating complexes. These different functionalities are associated with phylogenetically distinct clades and in many cases with specific microbial phyla. We propose that this new and abundant class of electron bifurcating enzyme be referred to as the Bfu family whose defining feature is a conserved bifurcating BfuBC core. This core contains FMN and six iron sulfur clusters and it interacts directly with ferredoxin (Fd) and NAD(H). Electrons to or from the third substrate are fed into the BfuBC core via BfuA. The other three known families of electron bifurcating enzyme (abbreviated as Nfn, EtfAB, and HdrA) contain a special FAD that bifurcates electrons to high and low potential pathways. The Bfu family are proposed to use a different electron bifurcation mechanism that involves a combination of FMN and three adjacent iron sulfur clusters, including a novel [2Fe-2S] cluster with pentacoordinate and partial non-Cys coordination. The absolute conservation of the redox cofactors of BfuBC in all members of the Bfu enzyme family indicate they have the same non-canonical mechanism to bifurcate electrons. A hypothetical catalytic mechanism is proposed as a basis for future spectroscopic analyses of Bfu family members.
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Affiliation(s)
- Gerrit J. Schut
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
| | - Dominik K. Haja
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
| | - Xiang Feng
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI, United States
| | - Farris L. Poole
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
| | - Huilin Li
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI, United States
| | - Michael W. W. Adams
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
- *Correspondence: Michael W. W. Adams, ; orcid.org/0000-0002-9796-5014
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Mariën Q, Ulčar B, Verleyen J, Vanthuyne B, Ganigué R. High-rate conversion of lactic acid-rich streams to caproic acid in a fermentative granular system. BIORESOURCE TECHNOLOGY 2022; 355:127250. [PMID: 35562021 DOI: 10.1016/j.biortech.2022.127250] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 04/26/2022] [Accepted: 04/27/2022] [Indexed: 06/15/2023]
Abstract
Lactic acid-driven chain elongation enables upgrading low-value organic streams into caproic acid. Recently, volumetric production rates over 0.5 g L-1 h-1have been reported for carbohydrate-rich streams in expanded granular sludge bed (EGSB) reactors. However, many target streams contain mixtures of carbohydrates and lactic acid, and little is known about their impact on product profile and microbial ecology, or the importance of carbohydrates as substrate to achieve high rates. This manuscript investigated varying glucose-to-lactate ratios and observed that decreasing glucose-content eliminated odd-chain by-products, while glucose omission required acetic acid addition to support lactic acid conversion. Decreasing the glucose-content fed resulted in decreasing amounts of granular biomass, with the disappearance of granules when no glucose was fed. Lowering the HRT to 0.3 days while feeding only lactic and acetic acid likely triggered re-granulation, enabling the highest lactic acid-driven caproic acid production rates reported thus far at 16.4 ± 1.7 g L-1 d-1.
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Affiliation(s)
- Quinten Mariën
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000 Ghent, Belgium; Center for Advanced Process Technology for Urban Resource Recovery (CAPTURE), Frieda Saeysstraat 1, 9000 Ghent, Belgium
| | - Barbara Ulčar
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000 Ghent, Belgium; Center for Advanced Process Technology for Urban Resource Recovery (CAPTURE), Frieda Saeysstraat 1, 9000 Ghent, Belgium
| | - Jesper Verleyen
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000 Ghent, Belgium
| | - Benjamin Vanthuyne
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000 Ghent, Belgium
| | - Ramon Ganigué
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000 Ghent, Belgium; Center for Advanced Process Technology for Urban Resource Recovery (CAPTURE), Frieda Saeysstraat 1, 9000 Ghent, Belgium.
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Wang C, Wang Y, Wang Y, Liu L, Wang D, Ju F, Xia Y, Zhang T. Impacts of food waste to sludge ratios on microbial dynamics and functional traits in thermophilic digesters. WATER RESEARCH 2022; 219:118590. [PMID: 35597218 DOI: 10.1016/j.watres.2022.118590] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 04/18/2022] [Accepted: 05/10/2022] [Indexed: 06/15/2023]
Abstract
A self-stabilizing microbial community lays the foundation of the efficient biochemical reactions of the anaerobic digestion (AD) process. Despite extensive profiling of microbial community dynamics under varying operating parameters, the effects of food waste (FW) to feeding sewage sludge (FSS) ratios on the microbial assembly, functional traits, and syntrophic interspecies interactions in thermophilic microbial consortia remain poorly understood. Here, we investigated the long-term impacts of the FW: FSS ratio on the thermophilic AD microbiome using genome-centric metagenomics. Both the short reads (SRs) assembly, and the iterative hybrid assembly (IHA) of SRs and nanopore long reads (LRs) were used to reconstruct metagenome-assembled genomes (MAGs) and four microbial clusters were identified, demonstrating different microbial dynamics patterns in response to varying FW:FSS ratios. Cluster C1-C3 were comprised of full functional members with genetic potentials in fulfilling empirical AD biochemical reactions, wherein, syntrophic decarboxylating acetogens could interact with methanogens, and some microbes could be energized by the electron bifurcation mechanism to drive thermodynamics unfavorable reactions. We found the co-existence of both acetogenic and hydrogenotrophic methanogens in the AD microbiome, and they altered their trophic groups to scavenge the methanogenic substrates in ensuring the methane generation in digesters with different FW:FSS ratios. Another interesting observation was that two phylogenetically close Thermotogota species showed a possible strong competition on carbon source inferred by the nearly complete genetic overlap of their relevant pathways.
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Affiliation(s)
- Chunxiao Wang
- Environmental Microbiome Engineering and Biotechnology Laboratory, Center for Environmental Engineering Research, Department of Civil Engineering, The University of Hong Kong, Hong Kong SAR, China
| | - Yulin Wang
- Environmental Microbiome Engineering and Biotechnology Laboratory, Center for Environmental Engineering Research, Department of Civil Engineering, The University of Hong Kong, Hong Kong SAR, China; State Key Laboratory of Microbial Biotechnology, Shandong University, Qingdao 266237, China
| | - Yubo Wang
- Key Laboratory of Coastal Environment and Resources of Zhejiang Province, School of Engineering, Westlake University, 18 Shilongshan Road, Hangzhou 310024, China
| | - Lei Liu
- Environmental Microbiome Engineering and Biotechnology Laboratory, Center for Environmental Engineering Research, Department of Civil Engineering, The University of Hong Kong, Hong Kong SAR, China
| | - Dou Wang
- Environmental Microbiome Engineering and Biotechnology Laboratory, Center for Environmental Engineering Research, Department of Civil Engineering, The University of Hong Kong, Hong Kong SAR, China
| | - Feng Ju
- Key Laboratory of Coastal Environment and Resources of Zhejiang Province, School of Engineering, Westlake University, 18 Shilongshan Road, Hangzhou 310024, China
| | - Yu Xia
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Tong Zhang
- Environmental Microbiome Engineering and Biotechnology Laboratory, Center for Environmental Engineering Research, Department of Civil Engineering, The University of Hong Kong, Hong Kong SAR, China.
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Kayastha K, Katsyv A, Himmrich C, Welsch S, Schuller JM, Ermler U, Müller V. Structure-based electron-confurcation mechanism of the Ldh-EtfAB complex. eLife 2022; 11:77095. [PMID: 35748623 PMCID: PMC9232219 DOI: 10.7554/elife.77095] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 05/22/2022] [Indexed: 01/22/2023] Open
Abstract
Lactate oxidation with NAD+ as electron acceptor is a highly endergonic reaction. Some anaerobic bacteria overcome the energetic hurdle by flavin-based electron bifurcation/confurcation (FBEB/FBEC) using a lactate dehydrogenase (Ldh) in concert with the electron-transferring proteins EtfA and EtfB. The electron cryo-microscopically characterized (Ldh-EtfAB)2 complex of Acetobacterium woodii at 2.43 Å resolution consists of a mobile EtfAB shuttle domain located between the rigid central Ldh and the peripheral EtfAB base units. The FADs of Ldh and the EtfAB shuttle domain contact each other thereby forming the D (dehydrogenation-connected) state. The intermediary Glu37 and Glu139 may harmonize the redox potentials between the FADs and the pyruvate/lactate pair crucial for FBEC. By integrating Alphafold2 calculations a plausible novel B (bifurcation-connected) state was obtained allowing electron transfer between the EtfAB base and shuttle FADs. Kinetic analysis of enzyme variants suggests a correlation between NAD+ binding site and D-to-B-state transition implicating a 75° rotation of the EtfAB shuttle domain. The FBEC inactivity when truncating the ferredoxin domain of EtfA substantiates its role as redox relay. Lactate oxidation in Ldh is assisted by the catalytic base His423 and a metal center. On this basis, a comprehensive catalytic mechanism of the FBEC process was proposed.
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Affiliation(s)
- Kanwal Kayastha
- Departments of Molecular Membrane Biology of the Max-Planck-Institut for Biophysics, Frankfurt am Main, Germany
| | - Alexander Katsyv
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Goethe University, Frankfurt am Main, Germany
| | - Christina Himmrich
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Goethe University, Frankfurt am Main, Germany
| | - Sonja Welsch
- Central Electron Microscopy Facility, Max Planck Institute of Biophysics, Frankfurt am Main, Germany
| | - Jan M Schuller
- SYNMICRO Research Center and Department of Chemistry, Philipps University, Marburg, Germany
| | - Ulrich Ermler
- Departments of Molecular Membrane Biology of the Max-Planck-Institut for Biophysics, Frankfurt am Main, Germany
| | - Volker Müller
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Goethe University, Frankfurt am Main, Germany
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Stickland metabolism in the gut. Nat Microbiol 2022; 7:603-604. [PMID: 35505246 DOI: 10.1038/s41564-022-01115-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Solchaga JI, Busalmen JP, Nercessian D. Unraveling Anaerobic Metabolisms in a Hypersaline Sediment. Front Microbiol 2022; 13:811432. [PMID: 35369499 PMCID: PMC8966722 DOI: 10.3389/fmicb.2022.811432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 01/31/2022] [Indexed: 11/13/2022] Open
Abstract
The knowledge on the microbial diversity inhabiting hypersaline sediments is still limited. In particular, existing data about anaerobic hypersaline archaea and bacteria are scarce and refer to a limited number of genera. The approach to obtain existing information has been almost exclusively attempting to grow every organism in axenic culture on the selected electron acceptor with a variety of electron donors. Here, a different approach has been used to interrogate the microbial community of submerged hypersaline sediment of Salitral Negro, Argentina, aiming at enriching consortia performing anaerobic respiration of different electron acceptor compounds, in which ecological associations can maximize the possibilities of successful growth. Growth of consortia was demonstrated on all offered electron acceptors, including fumarate, nitrate, sulfate, thiosulfate, dimethyl sulfoxide, and a polarized electrode. Halorubrum and Haloarcula representatives are here shown for the first time growing on lactate, using fumarate or a polarized electrode as the electron acceptor; in addition, they are shown also growing in sulfate-reducing consortia. Halorubrum representatives are for the first time shown to be growing in nitrate-reducing consortia, probably thanks to reduction of N2O produced by other consortium members. Fumarate respiration is indeed shown for the first time supporting growth of Halanaeroarchaeum and Halorhabdus belonging to the archaea, as well as growth of Halanaerobium, Halanaerobaculum, Sporohalobacter, and Acetohalobium belonging to the bacteria. Finally, evidence is presented suggesting growth of nanohaloarchaea in anaerobic conditions.
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Affiliation(s)
- Juan Ignacio Solchaga
- Instituto de Investigaciones Biológicas, Universidad Nacional de Mar del Plata - CONICET, Mar del Plata, Argentina
| | - Juan Pablo Busalmen
- Laboratorio de Bioelectroquímica, INTEMA - CONICET, Universidad Nacional de Mar del Plata, Mar del Plata, Argentina
| | - Débora Nercessian
- Instituto de Investigaciones Biológicas, Universidad Nacional de Mar del Plata - CONICET, Mar del Plata, Argentina
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Establishing Butyribacterium methylotrophicum as a platform organism for the production of biocommodities from liquid C1 metabolites. Appl Environ Microbiol 2022; 88:e0239321. [PMID: 35138930 DOI: 10.1128/aem.02393-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Using the Wood-Ljungdahl pathway, acetogens can non-photosynthetically fix gaseous C1 molecules preventing them from entering the atmosphere. Many acetogens can also grow on liquid C1 compounds such as formate and methanol which avoid the storage and mass transfer issues associated with gaseous C1 compounds. Substrate redox state also plays an important role in acetogen metabolism and can modulate products formed by these organisms. Butyribacterium methylotrophicum is an acetogen known for its ability to synthesize longer-chained molecules such as butyrate and butanol, which have significantly higher value than acetate or ethanol, from one-carbon (C1) compounds. We explored B. methylotrophicum's C1 metabolism by varying substrates, substrate concentrations and substrate feeding strategies to improve four-carbon product titers. Our results showed that formate utilization by B. methylotrophicum favored acetate production and methanol utilization favored butyrate production. Co-feeding of both substrates produced a high butyrate titer of 4 g/L when methanol was supplied in excess to formate. Testing of formate feeding strategies, in the presence of methanol, led to further increases in the butyrate to acetate ratio. Mixotrophic growth of liquid and gaseous C1 substrates expanded the B. methylotrophicum product profile as ethanol, butanol and lactate were produced in these conditions. We also showed that B. methylotrophicum is capable of producing caproate, a six-carbon product, presumably through chain elongation cycles of the reverse β-oxidation pathway. Furthermore, we demonstrated butanol production via heterologous gene expression. Our results indicate that both selection of appropriate substrates and genetic engineering play important roles in determining titers of desired products. Importance. Acetogenic bacteria can fix single-carbon (C1) molecules. However, improvements are needed to overcome poor product titers. Butyribacterium methylotrophicum can naturally ferment C1 compounds into longer-chained molecules such as butyrate alongside traditional acetate. Here we show that B. methylotrophicum can effectively grow on formate and methanol to produce high titers of butyrate. We improved ratios of butyrate to acetate through adjusted formate feeding strategies and produced higher value six-carbon molecules. We also expanded the B. methylotrophicum product profile with the addition of C1 gases as the organism produced ethanol, butanol and lactate. Furthermore, we developed a transformation protocol for B. methylotrophicum to facilitate genetic engineering of this organism for the circular bioeconomy.
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Autotrophic lactate production from H2 + CO2 using recombinant and fluorescent FAST-tagged Acetobacterium woodii strains. Appl Microbiol Biotechnol 2022; 106:1447-1458. [PMID: 35092454 PMCID: PMC8882112 DOI: 10.1007/s00253-022-11770-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 12/23/2021] [Accepted: 01/07/2022] [Indexed: 12/12/2022]
Abstract
AbstractLactate has various uses as industrial platform chemical, poly-lactic acid precursor or feedstock for anaerobic co-cultivations. The aim of this study was to construct and characterise Acetobacterium woodii strains capable of autotrophic lactate production. Therefore, the lctBCD genes, encoding the native Lct dehydrogenase complex, responsible for lactate consumption, were knocked out. Subsequently, a gene encoding a d-lactate dehydrogenase (LDHD) originating from Leuconostoc mesenteroides was expressed in A. woodii, either under the control of the anhydrotetracycline-inducible promoter Ptet or under the lactose-inducible promoter PbgaL. Moreover, LDHD was N-terminally fused to the oxygen-independent fluorescence-activating and absorption-shifting tag (FAST) and expressed in respective A. woodii strains. Cells that produced the LDHD fusion protein were capable of lactate production of up to 18.8 mM in autotrophic batch experiments using H2 + CO2 as energy and carbon source. Furthermore, cells showed a clear and bright fluorescence during exponential growth, as well as in the stationary phase after induction, mediated by the N-terminal FAST. Flow cytometry at the single-cell level revealed phenotypic heterogeneities for cells expressing the FAST-tagged LDHD fusion protein. This study shows that FAST provides a new reporter tool to quickly analyze gene expression over the course of growth experiments of A. woodii. Consequently, fluorescence-based reporters allow for faster and more targeted optimization of production strains.Key points
•Autotrophic lactate production was achieved with A. woodii.
•FAST functions as fluorescent marker protein in A. woodii.
•Fluorescence measurements on single-cell level revealed population heterogeneity.
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Sheridan PO, Louis P, Tsompanidou E, Shaw S, Harmsen HJ, Duncan SH, Flint HJ, Walker AW. Distribution, organization and expression of genes concerned with anaerobic lactate utilization in human intestinal bacteria. Microb Genom 2022; 8. [PMID: 35077342 PMCID: PMC8914356 DOI: 10.1099/mgen.0.000739] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Lactate accumulation in the human gut is linked to a range of deleterious health impacts. However, lactate is consumed and converted to the beneficial short-chain fatty acids butyrate and propionate by indigenous lactate-utilizing bacteria. To better understand the underlying genetic basis for lactate utilization, transcriptomic analyses were performed for two prominent lactate-utilizing species from the human gut, Anaerobutyricum soehngenii and Coprococcus catus, during growth on lactate, hexose sugar or hexose plus lactate. In A. soehngenii L2-7 six genes of the lactate utilization (lct) cluster, including NAD-independent d-lactate dehydrogenase (d-iLDH), were co-ordinately upregulated during growth on equimolar d- and l-lactate (dl-lactate). Upregulated genes included an acyl-CoA dehydrogenase related to butyryl-CoA dehydrogenase, which may play a role in transferring reducing equivalents between reduction of crotonyl-CoA and oxidation of lactate. Genes upregulated in C. catus GD/7 included a six-gene cluster (lap) encoding propionyl CoA-transferase, a putative lactoyl-CoA epimerase, lactoyl-CoA dehydratase and lactate permease, and two unlinked acyl-CoA dehydrogenase genes that are candidates for acryloyl-CoA reductase. A d-iLDH homologue in C. catus is encoded by a separate, partial lct, gene cluster, but not upregulated on lactate. While C. catus converts three mols of dl-lactate via the acrylate pathway to two mols propionate and one mol acetate, some of the acetate can be re-used with additional lactate to produce butyrate. A key regulatory difference is that while glucose partially repressed lct cluster expression in A. soehngenii, there was no repression of lactate-utilization genes by fructose in the non-glucose utilizer C. catus. This suggests that these species could occupy different ecological niches for lactate utilization in the gut, which may be important factors to consider when developing lactate-utilizing bacteria as novel candidate probiotics.
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Affiliation(s)
- Paul O Sheridan
- Gut Health Group, Rowett Institute, University of Aberdeen, Foresterhill, AB25 2ZD Aberdeen, UK
| | - Petra Louis
- Gut Health Group, Rowett Institute, University of Aberdeen, Foresterhill, AB25 2ZD Aberdeen, UK
| | - Eleni Tsompanidou
- Medical Microbiology and Infection Prevention, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, The Netherlands
| | - Sophie Shaw
- Centre for Genome-Enabled Biology and Medicine, 23 St. Machar Drive, AB24 3RY Aberdeen, UK
| | - Hermie J Harmsen
- Medical Microbiology and Infection Prevention, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, The Netherlands
| | - Sylvia H Duncan
- Gut Health Group, Rowett Institute, University of Aberdeen, Foresterhill, AB25 2ZD Aberdeen, UK
| | - Harry J Flint
- Gut Health Group, Rowett Institute, University of Aberdeen, Foresterhill, AB25 2ZD Aberdeen, UK
| | - Alan W Walker
- Gut Health Group, Rowett Institute, University of Aberdeen, Foresterhill, AB25 2ZD Aberdeen, UK
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Mostafa A, Im S, Kim J, Lim KH, Kim I, Kim DH. Electron bifurcation reactions in dark fermentation: An overview for better understanding and improvement. BIORESOURCE TECHNOLOGY 2022; 344:126327. [PMID: 34785332 DOI: 10.1016/j.biortech.2021.126327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 11/07/2021] [Accepted: 11/09/2021] [Indexed: 06/13/2023]
Abstract
Electron bifurcation (EB) is the most recently found mode of energy conservation, which involves both exergonic and endergonic electron transfer reactions to minimize energy loss. Several works have been devoted on EB reactions (EBRs) in anaerobic digestion but limited in dark fermentative hydrogen production (DF). Two main electron carriers in DF are ferredoxin (Fd) and reduced nicotinamide adenine dinucleotide (NADH), complicatedly involved in EB. Here, i) the importance of EB involvement in DF, ii) all EBRs possible to present in DF, as well as iii) the limitation of previous studies that tried incorporating any of EBRs in DF metabolic model, were highlighted. In addition, the concept of using metagenomic analysis for estimating the share of each EB reaction in the metabolic model, was proposed. This review is expected to initiate a new wave for studying EB, as a tool for explaining and predicting DF products.
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Affiliation(s)
- Alsayed Mostafa
- Department of Smart-city Engineering, Inha University, 100 Inha-ro, Michuhol-gu, Incheon 22212, Republic of Korea
| | - Seongwon Im
- Department of Smart-city Engineering, Inha University, 100 Inha-ro, Michuhol-gu, Incheon 22212, Republic of Korea
| | - Jimin Kim
- Department of Smart-city Engineering, Inha University, 100 Inha-ro, Michuhol-gu, Incheon 22212, Republic of Korea
| | - Kyeong-Ho Lim
- Department of Civil and Environmental Engineering, Kongju National University, Cheonan, Chungnam 31080, Republic of Korea
| | - Ijung Kim
- Department of Civil and Environmental Engineering, Hongik University, 94 Wausan-ro, Mapo-gu, Seoul 04066, Republic of Korea
| | - Dong-Hoon Kim
- Department of Smart-city Engineering, Inha University, 100 Inha-ro, Michuhol-gu, Incheon 22212, Republic of Korea.
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Wang H, Gu Y, Zhao D, Qiao Z, Zheng J, Gao J, Ren C, Xu Y. Caproicibacterium lactatifermentans sp. nov., isolated from pit clay used for the production of Chinese strong aroma-type liquor. Int J Syst Evol Microbiol 2022; 72. [PMID: 35085065 DOI: 10.1099/ijsem.0.005206] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Two recently reported bacterial strains that were identified as the dominant caproate-producing bacteria in pit clay, were further characterized to determine their phylogeny and taxonomy. The two strains, designated as LBM19010T and JNU-WLY1368, were short rod-shaped, Gram-stain-positive, non-motile and strictly anaerobic. Analysis of the 16S rRNA gene sequences revealed that strains LBM19010T and JNU-WLY1368 shared a 16S rRNA gene sequence similarity of 99.93 % and belonged to a recent proposed genus Caproicibacterium in the family Oscillospiraceae. The proposed type strain, LBM19010T, showed the highest 16S rRNA gene sequence similarity to Caproicibacterium amylolyticum LBM18003T (96.34%), followed by Caproiciproducens galactitolivorans JCM 30532T (94.14 %). The pairwise average nucleotide identity and average amino acid identity values between strains LBM19010T and LBM18003T were 74.84 and 76.18 %, respectively. Growth of strain LBM19010T occurred at pH 4.5-7.5 (optimum, pH 5.0-5.5), 20-40 °C (optimum, 35 °C) and with 0-1 % (w/v) NaCl (optimum, 0 %). Strains LBM19010T and JNU-WLY1368 were both able to ferment several hexoses, disaccharides, starch and lactate but not pentoses. Caproate and butyrate were the major end-products from glucose. The predominant cellular fatty acids (>10 %) of strain LBM19010T were C16 : 0 (56.3 %), C14 : 0 DMA (19.5 %) and C14 : 0 (14.9 %). The identified polar lipids of strain LBM19010T were diphosphatidylglycerol, phosphatidylglycerol, three unidentified phospholipids and nine unidentified glycolipids. Based on phylogenetic, phenotypic and chemotaxonomic evidence, strains LBM19010T and JNU-WLY1368 belong to a novel species of the genus Caproicibacterium, for which the name Caproicibacterium lactatifermentans sp. nov. is proposed. The type strain is LBM19010T (=GDMCC 1.1627T=JCM 33782T).
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Affiliation(s)
- Huilin Wang
- Lab of Brewing Microbiology and Applied Enzymology, Key Laboratory of Industrial Biotechnology of Ministry of Education, Jiangnan University, Wuxi 214122, PR China
| | - Yang Gu
- Lab of Brewing Microbiology and Applied Enzymology, Key Laboratory of Industrial Biotechnology of Ministry of Education, Jiangnan University, Wuxi 214122, PR China
| | - Dong Zhao
- China Light Industry Key Laboratory of Solid-state Fermentation for Strong Aroma-type Liquor, Yibin 644007, PR China
| | - Zongwei Qiao
- China Light Industry Key Laboratory of Solid-state Fermentation for Strong Aroma-type Liquor, Yibin 644007, PR China
| | - Jia Zheng
- China Light Industry Key Laboratory of Solid-state Fermentation for Strong Aroma-type Liquor, Yibin 644007, PR China
| | - Jiangjing Gao
- Lab of Brewing Microbiology and Applied Enzymology, Key Laboratory of Industrial Biotechnology of Ministry of Education, Jiangnan University, Wuxi 214122, PR China
| | - Cong Ren
- Lab of Brewing Microbiology and Applied Enzymology, Key Laboratory of Industrial Biotechnology of Ministry of Education, Jiangnan University, Wuxi 214122, PR China
| | - Yan Xu
- Lab of Brewing Microbiology and Applied Enzymology, Key Laboratory of Industrial Biotechnology of Ministry of Education, Jiangnan University, Wuxi 214122, PR China
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Lu S, Jin H, Wang Y, Tao Y. Genome-Wide Transcriptomic Analysis of n-Caproic Acid Production in Ruminococcaceae Bacterium CPB6 with Lactate Supplementation. J Microbiol Biotechnol 2021; 31:1533-1544. [PMID: 34489376 PMCID: PMC9705837 DOI: 10.4014/jmb.2107.07009] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 08/25/2021] [Accepted: 08/25/2021] [Indexed: 12/15/2022]
Abstract
n-Caproic acid (CA) is gaining increased attention due to its high value as a chemical feedstock. Ruminococcaceae bacterium strain CPB6 is an anaerobic mesophilic bacterium that is highly prolific in its ability to perform chain elongation of lactate to CA. However, little is known about the genome-wide transcriptional analysis of strain CPB6 for CA production triggered by the supplementation of exogenous lactate. In this study, cultivation of strain CPB6 was carried out in the absence and presence of lactate. Transcriptional profiles were analyzed using RNA-seq, and differentially expressed genes (DEGs) between the lactate-supplemented cells and control cells without lactate were analyzed. The results showed that lactate supplementation led to earlier CA p,roduction, and higher final CA titer and productivity. 295 genes were substrate and/or growth dependent, and these genes cover crucial functional categories. Specifically, 5 genes responsible for the reverse β-oxidation pathway, 11 genes encoding ATP-binding cassette (ABC) transporters, 6 genes encoding substrate-binding protein (SBP), and 4 genes encoding phosphotransferase system (PTS) transporters were strikingly upregulated in response to the addition of lactate. These genes would be candidates for future studies aiming at understanding the regulatory mechanism of lactate conversion into CA, as well as for the improvement of CA production in strain CPB6. The findings presented herein reveal unique insights into the biomolecular effect of lactate on CA production at the transcriptional level.
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Affiliation(s)
- Shaowen Lu
- CAS Key Laboratory of Environmental and Applied Microbiology and Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, P.R. China
| | - Hong Jin
- School of Basic Medical Science, Chengdu Medical College, Chengdu 610083, P.R. China
| | - Yi Wang
- Department of Biosystems Engineering, Auburn University, Auburn, Alabama, Alabama 36849, USA
| | - Yong Tao
- CAS Key Laboratory of Environmental and Applied Microbiology and Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, P.R. China,Faculty of Bioengineering, Sichuan University of Science and Engineering, Xueyuan Street 180#, Huixing Rd. Zigong 643000, P.R. China,Corresponding author Phone: 86-028-82890211 Fax: 86-028-82890211 E-mail:
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Meier AB, Oppermann S, Drake HL, Schmidt O. Organic carbon from graminoid roots as a driver of fermentation in a fen. FEMS Microbiol Ecol 2021; 97:6412523. [PMID: 34718537 DOI: 10.1093/femsec/fiab143] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 10/25/2021] [Indexed: 11/13/2022] Open
Abstract
Fen Schlöppnerbrunnen is a moderately acidic methane-emitting peatland overgrown by Molinia caerulea and other wetland graminoids (e.g. Carex rostrata). Recently, the accumulation of H2, an indicator for fermentation, was observed with anoxically incubated C. rostrata roots but not with root-free fen soil. Based on this finding, we hypothesized that root-derived organic carbon has a higher capacity to promote fermentation processes than peat organic carbon from root-free fen soil. To address this hypothesis, C. rostrata and M. caerulea roots were anoxically incubated with or without fen soil and the product profiles of root treatments were compared with those of root-free soil treatments. Ethanol, acetate, propionate, butyrate, H2 and CO2 accumulated in root treatments and collective amounts of carbon in accumulating products were 20-200 times higher than those in root-free soil treatments, in which mainly CO2 accumulated. Analyses of 16S rRNA and 16S rRNA gene sequences revealed that Clostridium, Propionispira and Rahnella, representatives of butyrate, propionate and mixed acid fermenters, respectively, were relatively enriched in root treatments. In contrast, differences of the microbial community before and after incubation were marginal in root-free soil treatments. Collectively, these findings supported the assumed stimulatory effect of root-derived organic carbon on fen fermenters.
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Affiliation(s)
- Anja B Meier
- Department of Ecological Microbiology, University of Bayreuth, Bayreuth 95440, Germany
| | - Sindy Oppermann
- Department of Ecological Microbiology, University of Bayreuth, Bayreuth 95440, Germany
| | - Harold L Drake
- Department of Ecological Microbiology, University of Bayreuth, Bayreuth 95440, Germany
| | - Oliver Schmidt
- Department of Ecological Microbiology, University of Bayreuth, Bayreuth 95440, Germany
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Li Y, Kreuzer M, Clayssen Q, Ebert MO, Ruscheweyh HJ, Sunagawa S, Kunz C, Attwood G, Amelchanka S, Terranova M. The rumen microbiome inhibits methane formation through dietary choline supplementation. Sci Rep 2021; 11:21761. [PMID: 34741032 PMCID: PMC8571420 DOI: 10.1038/s41598-021-01031-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Accepted: 10/18/2021] [Indexed: 11/11/2022] Open
Abstract
Enteric fermentation from ruminants is a primary source of anthropogenic methane emission. This study aims to add another approach for methane mitigation by manipulation of the rumen microbiome. Effects of choline supplementation on methane formation were quantified in vitro using the Rumen Simulation Technique. Supplementing 200 mM of choline chloride or choline bicarbonate reduced methane emissions by 97–100% after 15 days. Associated with the reduction of methane formation, metabolomics analysis revealed high post-treatment concentrations of ethanol, which likely served as a major hydrogen sink. Metagenome sequencing showed that the methanogen community was almost entirely lost, and choline-utilizing bacteria that can produce either lactate, ethanol or formate as hydrogen sinks were enriched. The taxa most strongly associated with methane mitigation were Megasphaera elsdenii and Denitrobacterium detoxificans, both capable of consuming lactate, which is an intermediate product and hydrogen sink. Accordingly, choline metabolism promoted the capability of bacteria to utilize alternative hydrogen sinks leading to a decline of hydrogen as a substrate for methane formation. However, fermentation of fibre and total organic matter could not be fully maintained with choline supplementation, while amino acid deamination and ethanolamine catabolism produced excessive ammonia, which would reduce feed efficiency and adversely affect live animal performance.
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Affiliation(s)
- Yang Li
- Institute of Agricultural Sciences, ETH Zurich, Universitaetstrasse 2, 8092, Zurich, Switzerland.
| | - Michael Kreuzer
- Institute of Agricultural Sciences, ETH Zurich, Universitaetstrasse 2, 8092, Zurich, Switzerland
| | - Quentin Clayssen
- Institute of Microbiology, ETH Zurich, Vladimir-Prelog-Weg 4, 8093, Zurich, Switzerland
| | - Marc-Olivier Ebert
- Laboratory of Organic Chemistry, ETH Zurich, Vladimir-Prelog-Weg 3, 8093, Zurich, Switzerland
| | | | - Shinichi Sunagawa
- Institute of Microbiology, ETH Zurich, Vladimir-Prelog-Weg 4, 8093, Zurich, Switzerland
| | - Carmen Kunz
- Institute of Agricultural Sciences, ETH Zurich, Universitaetstrasse 2, 8092, Zurich, Switzerland
| | - Graeme Attwood
- AgResearch Ltd. Grasslands Research Centre, Palmerston North, 4442, New Zealand
| | - Sergej Amelchanka
- ETH Zurich, AgroVet-Strickhof, Eschikon 27, 8315, Lindau, Switzerland
| | - Melissa Terranova
- ETH Zurich, AgroVet-Strickhof, Eschikon 27, 8315, Lindau, Switzerland
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50
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Shenbakam, Rao RJ, Prabhu S, Srirangarajan S, Rudresh V. Influence of antibacterial effects of tetracycline, laser, and photodynamic therapy on cell viability, cell damage, and virulence of Porphyromonas gingivalis. Photodiagnosis Photodyn Ther 2021; 36:102617. [PMID: 34740837 DOI: 10.1016/j.pdpdt.2021.102617] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 10/18/2021] [Accepted: 10/29/2021] [Indexed: 10/19/2022]
Abstract
INTRODUCTION This study compares and evaluates the efficacy of tetracycline, laser and photodynamic therapy on bacterial counts, cell damage, cell viability and neutralization of gingipains. MATERIAL AND METHODS P.gingivalis (ATCC 33,277) was cultured anaerobically. The minimal inhibitory concentration (MIC) for 50% inhibition of P.gingivalis by tetracycline, laser, and toluidine blue (TB) was determined using spectrophotometry. The antibacterial effects, cell viability, cell damage and neutralization of gingipains of the treated groups was evaluated by microbial culture and counting, 2,3 Bis 2 Methyloxy-4 Nitro-5 Sulphophenyl 2 H tetrazolium-5-Carboxaanilide (MTT) assay, lactate dehydrogenase (LDH) assay, and gingipain assay (BAPNA). RESULTS The MIC of tetracycline, toulidine, diode laser (810nmm; 0.5 Watts) is 1 µg/mL, 50 µg/mL and 15 s respectively. Comparative analysis for bacterial colony reduction was highest in tetracycline followed by PDT and then laser group at p < 0.01. MTT assay shows a significantly lesser number of viable cells in the tetracycline and PDT group when compared to laser group p < 0.01. Comparative analysis for cell damage using LDH shows the highest results for PDT followed by tetracycline and laser at p < 0.01. The highest neutralization of the gingipains is seen in the PDT group followed by tetracycline and laser groups at p < 0.01. CONCLUSION PDT shows highest antibacterial activity, gingipain neutralization, cell damage, and least number of viable cells in comparison with tetracycline and laser.
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Affiliation(s)
- Shenbakam
- Department of Periodontics, Bangalore Institute of Dental Sciences and Postgraduate research center, 5/3, Hosur road; Next to NIMHANS Convention center, Bangalore, Karnataka 560089, India
| | - Ravi J Rao
- Department of Periodontics, Bangalore Institute of Dental Sciences and Postgraduate research center, 5/3, Hosur road; Next to NIMHANS Convention center, Bangalore, Karnataka 560089, India
| | - Srikumar Prabhu
- Department of Periodontics, Bangalore Institute of Dental Sciences and Postgraduate research center, 5/3, Hosur road; Next to NIMHANS Convention center, Bangalore, Karnataka 560089, India
| | - S Srirangarajan
- Department of Periodontics, Bangalore Institute of Dental Sciences and Postgraduate research center, 5/3, Hosur road; Next to NIMHANS Convention center, Bangalore, Karnataka 560089, India.
| | - Vinaya Rudresh
- Department of Periodontics, Bangalore Institute of Dental Sciences and Postgraduate research center, 5/3, Hosur road; Next to NIMHANS Convention center, Bangalore, Karnataka 560089, India
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