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Arunachalam E, Keber FC, Law RC, Kumar CK, Shen Y, Park JO, Wühr M, Needleman DJ. Robustness of mitochondrial biogenesis and respiration explain aerobic glycolysis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.04.601975. [PMID: 39005310 PMCID: PMC11245115 DOI: 10.1101/2024.07.04.601975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
A long-standing observation is that in fast-growing cells, respiration rate declines with increasing growth rate and is compensated by an increase in fermentation, despite respiration being more efficient than fermentation. This apparent preference for fermentation even in the presence of oxygen is known as aerobic glycolysis, and occurs in bacteria, yeast, and cancer cells. Considerable work has focused on understanding the potential benefits that might justify this seemingly wasteful metabolic strategy, but its mechanistic basis remains unclear. Here we show that aerobic glycolysis results from the saturation of mitochondrial respiration and the decoupling of mitochondrial biogenesis from the production of other cellular components. Respiration rate is insensitive to acute perturbations of cellular energetic demands or nutrient supplies, and is explained simply by the amount of mitochondria per cell. Mitochondria accumulate at a nearly constant rate across different growth conditions, resulting in mitochondrial amount being largely determined by cell division time. In contrast, glucose uptake rate is not saturated, and is accurately predicted by the abundances and affinities of glucose transporters. Combining these models of glucose uptake and respiration provides a quantitative, mechanistic explanation for aerobic glycolysis. The robustness of specific respiration rate and mitochondrial biogenesis, paired with the flexibility of other bioenergetic and biosynthetic fluxes, may play a broad role in shaping eukaryotic cell metabolism.
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Affiliation(s)
- Easun Arunachalam
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
| | - Felix C. Keber
- Lewis-Sigler Institute for Integrative Genomics
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Richard C. Law
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, Los Angeles, CA, USA
| | - Chirag K. Kumar
- Lewis-Sigler Institute for Integrative Genomics
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Yihui Shen
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Junyoung O. Park
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, Los Angeles, CA, USA
| | - Martin Wühr
- Lewis-Sigler Institute for Integrative Genomics
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Daniel J. Needleman
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
- Center for Computational Biology, Flatiron Institute, New York, NY, USA
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2
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Wang X, Hong Y, Wang Z, Yuan Y, Sun D. High capacities of carbon capture and photosynthesis of a novel organic carbon-fixing microalgae in municipal wastewater: From mutagenesis, screening, ability evaluation to mechanism analysis. WATER RESEARCH 2024; 257:121722. [PMID: 38723359 DOI: 10.1016/j.watres.2024.121722] [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: 01/01/2024] [Revised: 04/30/2024] [Accepted: 05/03/2024] [Indexed: 05/29/2024]
Abstract
The development of wastewater treatment processes capable of reducing and fixing carbon is currently a hot topic in the wastewater treatment field. Microalgae possess a natural carbon-fixing advantage, and microalgae that can symbiotically coexist with indigenous bacteria in actual wastewater attract more significant attention. Ultraviolet (UV) mutagenesis and dissolved organic carbon (DOC) acclimation were applied to strengthen the carbon-fixing performance of microalgae in this study. The mechanisms associated with microalgal water purification ability, gene regulation at the molecular level and photosynthetic potential under different trophic modes resulting from carbon fixation and transformation were disclosed. The superior performance of Chlorella sp. MHQ2 was eventually screened out among a large number of mutants generated from 3 wild-type Chlorella strains. Results indicated that the dry cell weight of the optimal species Chlorella sp. HQ mutant MHQ2 was 1.91 times that of the wild strain in the pure algal system, more carbon from municipal wastewater (MW) were transferred to the microalgae and re-entered into the biological cycle through resource utilization. In addition, COD, NH3-N and TP removal efficiencies of MW by Chlorella sp. MHQ2 were found to increase to 95.8% (1.1-times), 96.4% (1.4-times), and 92.9% (1.2-times), respectively, under the extra DOC supply and the assistance of indigenous bacteria in the MW. In the transcriptome analysis of the logarithmic phase, the glycolytic pathway was inhibited, and the pentose phosphate pathway was mainly carried out for microalgal life activities, further promoting efficient energy utilization. Upon analysis of carbon capture capacity and photosynthetic potential in trophic mode, the addition of NaHCO3 increased the photosynthetic rate of Chlorella sp. MHQ2 in mixotrophy whereas it was attenuated in autotrophy. This study could provide a new perspective for the study of resource utilization and microalgae carbon- fixing mechanisms in the actual wastewater treatment process.
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Affiliation(s)
- Xiaoyan Wang
- Beijing Key Lab for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China; Engineering Research Center for Water Pollution Source Control & Eco-Remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
| | - Yu Hong
- Beijing Key Lab for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China; Engineering Research Center for Water Pollution Source Control & Eco-Remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China.
| | - Zeyuan Wang
- Beijing Key Lab for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China; Engineering Research Center for Water Pollution Source Control & Eco-Remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
| | - Yaqian Yuan
- Beijing Key Lab for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China; Engineering Research Center for Water Pollution Source Control & Eco-Remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
| | - Dezhi Sun
- Beijing Key Lab for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China; Engineering Research Center for Water Pollution Source Control & Eco-Remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
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3
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Meijnikman AS, Nieuwdorp M, Schnabl B. Endogenous ethanol production in health and disease. Nat Rev Gastroenterol Hepatol 2024:10.1038/s41575-024-00937-w. [PMID: 38831008 DOI: 10.1038/s41575-024-00937-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/23/2024] [Indexed: 06/05/2024]
Abstract
The gut microbiome exerts metabolic actions on distal tissues and organs outside the intestine, partly through microbial metabolites that diffuse into the circulation. The disruption of gut homeostasis results in changes to microbial metabolites, and more than half of the variance in the plasma metabolome can be explained by the gut microbiome. Ethanol is a major microbial metabolite that is produced in the intestine of nearly all individuals; however, elevated ethanol production is associated with pathological conditions such as metabolic dysfunction-associated steatotic liver disease and auto-brewery syndrome, in which the liver's capacity to metabolize ethanol is surpassed. In this Review, we describe the mechanisms underlying excessive ethanol production in the gut and the role of ethanol catabolism in mediating pathogenic effects of ethanol on the liver and host metabolism. We conclude by discussing approaches to target excessive ethanol production by gut bacteria.
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Affiliation(s)
| | - Max Nieuwdorp
- Department of Internal Medicine, Amsterdam University Medical Centers, Location AMC, Amsterdam, Netherlands
- Department of Experimental Vascular Medicine, Amsterdam University Medical Centers, Location AMC, Amsterdam, Netherlands
- Diabeter Centrum Amsterdam, Amsterdam, Netherlands
| | - Bernd Schnabl
- Department of Medicine, University of California San Diego, La Jolla, CA, USA.
- Department of Medicine, VA San Diego Healthcare System, San Diego, CA, USA.
- Center for Innovative Phage Applications and Therapeutics, University of California San Diego, La Jolla, CA, USA.
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4
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Lee JH, Oh HM. Effects of Light and Dark Conditions on the Transcriptome of Aging Cultures of Candidatus Puniceispirillum marinum IMCC1322. J Microbiol 2024; 62:297-314. [PMID: 38662311 DOI: 10.1007/s12275-024-00125-0] [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: 08/22/2023] [Revised: 02/19/2024] [Accepted: 02/19/2024] [Indexed: 04/26/2024]
Abstract
To elucidate the function of proteorhodopsin in Candidatus Puniceispirillum marinum strain IMCC1322, a cultivated representative of SAR116, we produced RNA-seq data under laboratory conditions. We examined the transcriptomes of six different cultures, including sets of expression changes under constant dark (DD), constant light (LL), and diel-cycled (LD; 14 h light: 10 h dark) conditions at the exponential and stationary/death phases. Prepared mRNA extracted from the six samples was analyzed on the Solexa Genome Analyzer with 36 cycles. Differentially expressed genes on the IMCC1322 genome were distinguished as four clusters by K-mean clustering and each CDS (n = 2546) was annotated based on the KEGG BRITE hierarchy. Cluster 0 (n = 1573) covered most constitutive genes including proteorhodopsin, retinoids, and glycolysis/TCA cycle. Cluster 1 genes (n = 754) were upregulated in stationary/death phase under constant dark conditions and included genes associated with bacterial defense, membrane transporters, nitrogen metabolism, and senescence signaling. Cluster 2 genes (n = 197) demonstrated upregulation in exponential phase cultures and included genes involved in genes for oxidative phosphorylation, translation factors, and transcription machinery. Cluster 3 (n = 22) contained light-stimulated upregulated genes expressed under stationary/phases. Stringent response genes belonged to cluster 2, but affected genes spanned various cellular processes such as amino acids, nucleotides, translation, transcription, glycolysis, fatty acids, and cell wall components. The coordinated expression of antagonistic stringent genes, including mazG, ppx/gppA, and spoT/relA may provide insight into the controlled cultural response observed between constant light and constant dark conditions in IMCC1322 cultures, regardless of cell numbers and biomass.
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Affiliation(s)
- Ji Hyen Lee
- Department of Pediatrics, Ewha Womans University School of Medicine, Seoul, 07804, Republic of Korea
| | - Hyun-Myung Oh
- Institute of Liberal Arts Education, Pukyong National University, Busan, 48547, Republic of Korea.
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5
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Chan C, Groisman EA. Chaperone Hsp70 helps Salmonella survive infection-relevant stress by reducing protein synthesis. PLoS Biol 2024; 22:e3002560. [PMID: 38574172 PMCID: PMC10994381 DOI: 10.1371/journal.pbio.3002560] [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: 12/03/2023] [Accepted: 02/23/2024] [Indexed: 04/06/2024] Open
Abstract
In all domains of life, Hsp70 chaperones preserve protein homeostasis by promoting protein folding and degradation and preventing protein aggregation. We now report that the Hsp70 from the bacterial pathogen Salmonella enterica serovar Typhimurium-termed DnaK-independently reduces protein synthesis in vitro and in S. Typhimurium facing cytoplasmic Mg2+ starvation, a condition encountered during infection. This reduction reflects a 3-fold increase in ribosome association with DnaK and a 30-fold decrease in ribosome association with trigger factor, the chaperone normally associated with translating ribosomes. Surprisingly, this reduction does not involve J-domain cochaperones, unlike previously known functions of DnaK. Removing the 74 C-terminal amino acids of the 638-residue long DnaK impeded DnaK association with ribosomes and reduction of protein synthesis, rendering S. Typhimurium defective in protein homeostasis during cytoplasmic Mg2+ starvation. DnaK-dependent reduction in protein synthesis is critical for survival against Mg2+ starvation because inhibiting protein synthesis in a dnaK-independent manner overcame the 10,000-fold loss in viability resulting from DnaK truncation. Our results indicate that DnaK protects bacteria from infection-relevant stresses by coordinating protein synthesis with protein folding capacity.
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Affiliation(s)
- Carissa Chan
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, United States of America
| | - Eduardo A. Groisman
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, United States of America
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6
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Ortega-Arzola E, Higgins PM, Cockell CS. The minimum energy required to build a cell. Sci Rep 2024; 14:5267. [PMID: 38438463 DOI: 10.1038/s41598-024-54303-6] [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: 10/04/2023] [Accepted: 02/11/2024] [Indexed: 03/06/2024] Open
Abstract
Understanding the energy requirements for cell synthesis accurately and comprehensively has been a longstanding challenge. We introduce a computational model that estimates the minimum energy necessary to build any cell from its constituent parts. This method combines omics and internal cell compositions from various sources to calculate the Gibbs Free Energy of biosynthesis independently of specific metabolic pathways. Our public tool, Synercell, can be used with other models for minumum species-specific energy estimations in any well-sequenced species. The energy for synthesising the genome, transcriptome, proteome, and lipid bilayer of four cell types: Escherichia coli, Saccharomyces cerevisiae, an average mammalian cell and JCVI-syn3A were estimated. Their modelled minimum synthesis energies at 298 K were 9.54 × 10 - 11 J/cell, 4.99 × 10 - 9 J/cell, 3.71 × 10 - 7 J/cell and 3.69 × 10 - 12 respectively. Gram-for-gram synthesis of lipid bilayers requires the most energy, followed by the proteome, genome, and transcriptome. The average per gram cost of biomass synthesis is in the 300s of J/g for all four cells. Implications for the generalisability of cell construction and applications to biogeosciences, cellular biology, biotechnology, and astrobiology are discussed.
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Affiliation(s)
- Edwin Ortega-Arzola
- UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh, Edinburgh, UK.
| | - Peter M Higgins
- UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh, Edinburgh, UK
- Department of Earth Sciences, University of Toronto, Toronto, ON, Canada
| | - Charles S Cockell
- UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh, Edinburgh, UK
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Chen J, Shen L, Li Y, Cao H, Chen C, Zhang G, Xu Z, Lu Y. Insights into the nitrogen transformation mechanism of Pseudomonas sp. Y15 capable of heterotrophic nitrification and aerobic denitrification. ENVIRONMENTAL RESEARCH 2024; 240:117595. [PMID: 37926232 DOI: 10.1016/j.envres.2023.117595] [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: 08/27/2023] [Revised: 10/27/2023] [Accepted: 11/02/2023] [Indexed: 11/07/2023]
Abstract
Excessive nitrogen (N) discharged in water is a major cause of eutrophication and other severe environmental issues. Biological N removal via heterotrophic nitrification and aerobic denitrification (HN-AD) has drawn particular attention, owing to the merit of concurrent nitrification and denitrification inside one cell. However, the mechanisms underlying N transformation during HN-AD remain unclear. In the present study, the HN-AD strain Pseudomonas sp. Y15 (Y15) was isolated to explore the N distribution and flow, based on stoichiometry and energetics. The total N removal efficiency by Y15 increased linearly with C/N ratio (in the range of 5-15) to ∼96.8%. Of this, ∼32.2% and ∼64.6% were transformed into gas-N and biomass-N, respectively. A new intracellular N metabolic bypass (NO → NO2) was found, to address the substantial gaseous N production during HN-AD. Concering energetics, the large portion of the biomass-N is ascribed to the synthesis of the amino acids that consume low energy. Finally, two novel stoichiometric equations for different N sources were proposed, to describe the overall HN-AD process. This study deepens the fundamental knowledge on HN-AD bacteria and enlightens their use in treating N-contaminated wastewater.
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Affiliation(s)
- Jinliang Chen
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, The Key Laboratory for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, 361005, PR China
| | - Liang Shen
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, The Key Laboratory for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, 361005, PR China.
| | - Yu Li
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, The Key Laboratory for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, 361005, PR China
| | - Haipeng Cao
- School of Life Sciences, Guizhou Normal University, Guiyang, 550025, PR China
| | - Cuixue Chen
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, The Key Laboratory for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, 361005, PR China
| | - Guoliang Zhang
- Institute of Oceanic and Environmental Chemical Engineering, State Key Lab Breeding Base of Green Chemical Synthesis Technology, Zhejiang University of Technology, Hangzhou, 310014, PR China
| | - Zehai Xu
- Institute of Oceanic and Environmental Chemical Engineering, State Key Lab Breeding Base of Green Chemical Synthesis Technology, Zhejiang University of Technology, Hangzhou, 310014, PR China
| | - Yinghua Lu
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, The Key Laboratory for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, 361005, PR China.
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8
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Liu H, Wang Y, Zhang Z, Qi H, Zhang Y, Li W, Shi Q, Xie X. Nutrient condition modulates the antibiotic tolerance of Pseudomonas aeruginosa. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 904:166749. [PMID: 37659534 DOI: 10.1016/j.scitotenv.2023.166749] [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: 06/14/2023] [Revised: 08/06/2023] [Accepted: 08/30/2023] [Indexed: 09/04/2023]
Abstract
The variation in nutrient content across diverse environments has a significant impact on the survival and metabolism of microorganisms. In this study, we examined the influence of nutrients on the antibiotic tolerance of the PAO1 strain of Pseudomonas aeruginosa. Our findings indicate that under nutrient-rich conditions, this strain exhibited relatively high tolerance to ceftazidime, chloramphenicol, and tetracycline, but not aminoglycosides and fluoroquinolones. Transcriptome analysis revealed that genes associated with antibiotic tolerance were expressed more efficiently in nutrient-rich media, including ribosomal protein genes and multidrug efflux pump genes, which conferred higher tetracycline tolerance to the strain. Furthermore, the genes responsible for translation, biosynthesis, and oxidative phosphorylation were suppressed when nutrients were limited, resulting in decreased metabolic activity and lower sensitivity to ciprofloxacin. Artificial interference with ATP synthesis utilizing arsenate confirmed that the curtailment of energy provision bolstered the observed tolerance to ciprofloxacin. In general, our results indicate that this strain of P. aeruginosa tends to activate its intrinsic resistance mechanisms in nutrient-rich environments, thereby enhancing resistance to certain antibiotics. Conversely, in nutrient-limited environments, the strain is more likely to enter a dormant state, which enables it to tolerate antibiotics to which it would otherwise be sensitive. These findings further suggest that antibiotics released in environments with varying eutrophication levels may have divergent effects on the development of bacterial antibiotic resistance.
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Affiliation(s)
- Huizhong Liu
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Yingsi Wang
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Zhiqing Zhang
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Hong Qi
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Yu Zhang
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Wenru Li
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Qingshan Shi
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Xiaobao Xie
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China.
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Winter SE, Bäumler AJ. Gut dysbiosis: Ecological causes and causative effects on human disease. Proc Natl Acad Sci U S A 2023; 120:e2316579120. [PMID: 38048456 PMCID: PMC10722970 DOI: 10.1073/pnas.2316579120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 11/02/2023] [Indexed: 12/06/2023] Open
Abstract
The gut microbiota plays a role in many human diseases, but high-throughput sequence analysis does not provide a straightforward path for defining healthy microbial communities. Therefore, understanding mechanisms that drive compositional changes during disease (gut dysbiosis) continues to be a central goal in microbiome research. Insights from the microbial pathogenesis field show that an ecological cause for gut dysbiosis is an increased availability of host-derived respiratory electron acceptors, which are dominant drivers of microbial community composition. Similar changes in the host environment also drive gut dysbiosis in several chronic human illnesses, and a better understanding of the underlying mechanisms informs approaches to causatively link compositional changes in the gut microbiota to an exacerbation of symptoms. The emerging picture suggests that homeostasis is maintained by host functions that control the availability of resources governing microbial growth. Defining dysbiosis as a weakening of these host functions directs attention to the underlying cause and identifies potential targets for therapeutic intervention.
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Affiliation(s)
- Sebastian E. Winter
- Department of Medicine, Division of Infectious Diseases, University of California, Davis, CA95616
- Department of Medical Microbiology and Immunology, University of California, Davis, CA95616
| | - Andreas J. Bäumler
- Department of Medical Microbiology and Immunology, University of California, Davis, CA95616
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10
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Terzioglu M, Veeroja K, Montonen T, Ihalainen TO, Salminen TS, Bénit P, Rustin P, Chang YT, Nagai T, Jacobs HT. Mitochondrial temperature homeostasis resists external metabolic stresses. eLife 2023; 12:RP89232. [PMID: 38079477 PMCID: PMC10712956 DOI: 10.7554/elife.89232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2023] Open
Abstract
Based on studies with a fluorescent reporter dye, Mito Thermo Yellow (MTY), and the genetically encoded gTEMP ratiometric fluorescent temperature indicator targeted to mitochondria, the temperature of active mitochondria in four mammalian and one insect cell line was estimated to be up to 15°C above that of the external environment to which the cells were exposed. High mitochondrial temperature was maintained in the face of a variety of metabolic stresses, including substrate starvation or modification, decreased ATP demand due to inhibition of cytosolic protein synthesis, inhibition of the mitochondrial adenine nucleotide transporter and, if an auxiliary pathway for electron transfer was available via the alternative oxidase, even respiratory poisons acting downstream of oxidative phosphorylation (OXPHOS) complex I. We propose that the high temperature of active mitochondria is an inescapable consequence of the biochemistry of OXPHOS and is homeostatically maintained as a primary feature of mitochondrial metabolism.
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Affiliation(s)
- Mügen Terzioglu
- Faculty of Medicine and Health Technology, Tampere UniversityTampereFinland
| | - Kristo Veeroja
- Faculty of Medicine and Health Technology, Tampere UniversityTampereFinland
| | - Toni Montonen
- Faculty of Medicine and Health Technology, Tampere UniversityTampereFinland
| | - Teemu O Ihalainen
- Faculty of Medicine and Health Technology, Tampere UniversityTampereFinland
| | - Tiina S Salminen
- Faculty of Medicine and Health Technology, Tampere UniversityTampereFinland
| | - Paule Bénit
- Université Paris Cité, Inserm, Maladies Neurodéveloppementales et NeurovasculairesParisFrance
| | - Pierre Rustin
- Université Paris Cité, Inserm, Maladies Neurodéveloppementales et NeurovasculairesParisFrance
| | - Young-Tae Chang
- SANKEN (The Institute of Scientific and Industrial Research), Osaka UniversityIbarakiJapan
| | | | - Howard T Jacobs
- Faculty of Medicine and Health Technology, Tampere UniversityTampereFinland
- Department of Environment and Genetics, La Trobe UniversityMelbourneAustralia
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11
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McDaniel EA, Scarborough M, Mulat DG, Lin X, Sampara PS, Olson HM, Young RP, Eder EK, Attah IK, Markillie LM, Hoyt DW, Lipton MS, Hallam SJ, Ziels RM. Diverse electron carriers drive syntrophic interactions in an enriched anaerobic acetate-oxidizing consortium. THE ISME JOURNAL 2023; 17:2326-2339. [PMID: 37880541 PMCID: PMC10689502 DOI: 10.1038/s41396-023-01542-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 10/09/2023] [Accepted: 10/11/2023] [Indexed: 10/27/2023]
Abstract
In many anoxic environments, syntrophic acetate oxidation (SAO) is a key pathway mediating the conversion of acetate into methane through obligate cross-feeding interactions between SAO bacteria (SAOB) and methanogenic archaea. The SAO pathway is particularly important in engineered environments such as anaerobic digestion (AD) systems operating at thermophilic temperatures and/or with high ammonia. Despite the widespread importance of SAOB to the stability of the AD process, little is known about their in situ physiologies due to typically low biomass yields and resistance to isolation. Here, we performed a long-term (300-day) continuous enrichment of a thermophilic (55 °C) SAO community from a municipal AD system using acetate as the sole carbon source. Over 80% of the enriched bioreactor metagenome belonged to a three-member consortium, including an acetate-oxidizing bacterium affiliated with DTU068 encoding for carbon dioxide, hydrogen, and formate production, along with two methanogenic archaea affiliated with Methanothermobacter_A. Stable isotope probing was coupled with metaproteogenomics to quantify carbon flux into each community member during acetate conversion and inform metabolic reconstruction and genome-scale modeling. This effort revealed that the two Methanothermobacter_A species differed in their preferred electron donors, with one possessing the ability to grow on formate and the other only consuming hydrogen. A thermodynamic analysis suggested that the presence of the formate-consuming methanogen broadened the environmental conditions where ATP production from SAO was favorable. Collectively, these results highlight how flexibility in electron partitioning during SAO likely governs community structure and fitness through thermodynamic-driven mutualism, shedding valuable insights into the metabolic underpinnings of this key functional group within methanogenic ecosystems.
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Affiliation(s)
- Elizabeth A McDaniel
- Department of Civil Engineering, The University of British Columbia, Vancouver, BC, Canada
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC, Canada
| | - Matthew Scarborough
- Department of Civil and Environmental Engineering, University of Vermont, Burlington, VT, USA
| | - Daniel Girma Mulat
- Department of Civil Engineering, The University of British Columbia, Vancouver, BC, Canada
| | - Xuan Lin
- Department of Civil Engineering, The University of British Columbia, Vancouver, BC, Canada
| | - Pranav S Sampara
- Department of Civil Engineering, The University of British Columbia, Vancouver, BC, Canada
| | - Heather M Olson
- Environmental and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Robert P Young
- Environmental and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Elizabeth K Eder
- Environmental and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Isaac K Attah
- Environmental and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Lye Meng Markillie
- Environmental and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - David W Hoyt
- Environmental and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Mary S Lipton
- Environmental and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Steven J Hallam
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC, Canada
- ECOSCOPE Training Program, The University of British Columbia, Vancouver, BC, Canada
- Graduate Program in Bioinformatics, The University of British Columbia, Vancouver, BC, Canada
- Genome Science and Technology Program, The University of British Columbia, Vancouver, BC, Canada
- Life Sciences Institute, The University of British Columbia, Vancouver, BC, Canada
| | - Ryan M Ziels
- Department of Civil Engineering, The University of British Columbia, Vancouver, BC, Canada.
- Genome Science and Technology Program, The University of British Columbia, Vancouver, BC, Canada.
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12
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Westerhoff HV. On paradoxes between optimal growth, metabolic control analysis, and flux balance analysis. Biosystems 2023; 233:104998. [PMID: 37591451 DOI: 10.1016/j.biosystems.2023.104998] [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: 05/01/2023] [Revised: 08/04/2023] [Accepted: 08/08/2023] [Indexed: 08/19/2023]
Abstract
In Microbiology it is often assumed that growth rate is maximal. This may be taken to suggest that the dependence of the growth rate on every enzyme activity is at the top of an inverse-parabolic function, i.e. that all flux control coefficients should equal zero. This might seem to imply that the sum of these flux control coefficients equals zero. According to the summation law of Metabolic Control Analysis (MCA) the sum of flux control coefficients should equal 1 however. And in Flux Balance Analysis (FBA) catabolism is often limited by a hard bound, causing catabolism to fully control the fluxes, again in apparent contrast with a flux control coefficient of zero. Here we resolve these paradoxes (apparent contradictions) in an analysis that uses the 'Edinburgh pathway', the 'Amsterdam pathway', as well as a generic metabolic network providing the building blocks or Gibbs energy for microbial growth. We review and show that (i) optimization depends on so-called enzyme control coefficients rather than the 'catalytic control coefficients' of MCA's summation law, (ii) when optimization occurs at fixed total protein, the former differ from the latter to the extent that they may all become equal to zero in the optimum state, (iii) in more realistic scenarios of optimization where catalytically inert biomass is compensating or maintenance metabolism is taken into consideration, the optimum enzyme concentrations should not be expected to equal those that maximize the specific growth rate, (iv) optimization may be in terms of yield rather than specific growth rate, which resolves the paradox because the sum of catalytic control coefficients on yield equals 0, (v) FBA effectively maximizes growth yield, and for yield the summation law states 0 rather than 1, thereby removing the paradox, (vi) furthermore, FBA then comes more often to a 'hard optimum' defined by a maximum catabolic flux and a catabolic-enzyme control coefficient of 1. The trade-off between maintenance metabolism and growth is highlighted as worthy of further analysis.
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Affiliation(s)
- Hans V Westerhoff
- Department of Molecular Cell Biology, Vrije Universiteit Amsterdam, A-Life, De Boelelaan 1085, 1081 HV, Amsterdam, the Netherlands; Synthetic Systems Biology and Nuclear Organization, Swammerdam Institute for Life Sciences, University of Amsterdam, 1098 XH, Amsterdam, the Netherlands; School of Biological Sciences, Medicine and Health, University of Manchester, Manchester, United Kingdom; Stellenbosch Institute for Advanced Study (STIAS), Wallenberg Research Centre at Stellenbosch University, Stellenbosch, 7600, South Africa.
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13
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Nisson DM, Walters CC, Chacón-Patiño ML, Weisbrod CR, Kieft TL, Sherwood Lollar B, Warr O, Castillo J, Perl SM, Cason ED, Freifeld BM, Onstott TC. Radiolytically reworked Archean organic matter in a habitable deep ancient high-temperature brine. Nat Commun 2023; 14:6163. [PMID: 37789019 PMCID: PMC10547683 DOI: 10.1038/s41467-023-41900-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 09/20/2023] [Indexed: 10/05/2023] Open
Abstract
Investigations of abiotic and biotic contributions to dissolved organic carbon (DOC) are required to constrain microbial habitability in continental subsurface fluids. Here we investigate a large (101-283 mg C/L) DOC pool in an ancient (>1Ga), high temperature (45-55 °C), low biomass (102-104 cells/mL), and deep (3.2 km) brine from an uranium-enriched South African gold mine. Excitation-emission matrices (EEMs), negative electrospray ionization (-ESI) 21 tesla Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS), and amino acid analyses suggest the brine DOC is primarily radiolytically oxidized kerogen-rich shales or reefs, methane and ethane, with trace amounts of C3-C6 hydrocarbons and organic sulfides. δ2H and δ13C of C1-C3 hydrocarbons are consistent with abiotic origins. These findings suggest water-rock processes control redox and C cycling, helping support a meagre, slow biosphere over geologic time. A radiolytic-driven, habitable brine may signal similar settings are good targets in the search for life beyond Earth.
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Affiliation(s)
- Devan M Nisson
- Department of Geosciences, Princeton University, Princeton, NJ, 08540, USA.
| | | | | | - Chad R Weisbrod
- National High Magnetic Field Laboratory, Tallahassee, FL, 32310, USA
| | - Thomas L Kieft
- Department of Biology, New Mexico Institute of Mining and Technology, Socorro, NM, 87801, USA
| | - Barbara Sherwood Lollar
- Department of Earth Sciences, University of Toronto, Toronto, ON, M5S 3B1, Canada
- Institut de Physique du Globe de Paris (IPGP), Université Paris Cité, 1 rue Jussieu, 75005, Paris, France
| | - Oliver Warr
- Department of Earth Sciences, University of Ottawa, Ottawa, ON, K1N 6N5, Canada
| | - Julio Castillo
- Department of Microbiology and Biochemistry, University of the Free State, Bloemfontein, 9300, South Africa
| | - Scott M Perl
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, 91109, USA
| | - Errol D Cason
- Department of Animal Sciences, University of the Free State, Bloemfontein, 9300, South Africa
| | | | - Tullis C Onstott
- Department of Geosciences, Princeton University, Princeton, NJ, 08540, USA
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14
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Roberts MD, McCarthy JJ, Hornberger TA, Phillips SM, Mackey AL, Nader GA, Boppart MD, Kavazis AN, Reidy PT, Ogasawara R, Libardi CA, Ugrinowitsch C, Booth FW, Esser KA. Mechanisms of mechanical overload-induced skeletal muscle hypertrophy: current understanding and future directions. Physiol Rev 2023; 103:2679-2757. [PMID: 37382939 PMCID: PMC10625844 DOI: 10.1152/physrev.00039.2022] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 06/12/2023] [Accepted: 06/21/2023] [Indexed: 06/30/2023] Open
Abstract
Mechanisms underlying mechanical overload-induced skeletal muscle hypertrophy have been extensively researched since the landmark report by Morpurgo (1897) of "work-induced hypertrophy" in dogs that were treadmill trained. Much of the preclinical rodent and human resistance training research to date supports that involved mechanisms include enhanced mammalian/mechanistic target of rapamycin complex 1 (mTORC1) signaling, an expansion in translational capacity through ribosome biogenesis, increased satellite cell abundance and myonuclear accretion, and postexercise elevations in muscle protein synthesis rates. However, several lines of past and emerging evidence suggest that additional mechanisms that feed into or are independent of these processes are also involved. This review first provides a historical account of how mechanistic research into skeletal muscle hypertrophy has progressed. A comprehensive list of mechanisms associated with skeletal muscle hypertrophy is then outlined, and areas of disagreement involving these mechanisms are presented. Finally, future research directions involving many of the discussed mechanisms are proposed.
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Affiliation(s)
- Michael D Roberts
- School of Kinesiology, Auburn University, Auburn, Alabama, United States
| | - John J McCarthy
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, Kentucky, United States
| | - Troy A Hornberger
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, Wisconsin, United States
| | - Stuart M Phillips
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Abigail L Mackey
- Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery, Copenhagen University Hospital-Bispebjerg and Frederiksberg, and Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Gustavo A Nader
- Department of Kinesiology and Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, United States
| | - Marni D Boppart
- Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States
| | - Andreas N Kavazis
- School of Kinesiology, Auburn University, Auburn, Alabama, United States
| | - Paul T Reidy
- Department of Kinesiology, Nutrition and Health, Miami University, Oxford, Ohio, United States
| | - Riki Ogasawara
- Healthy Food Science Research Group, Cellular and Molecular Biotechnology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
| | - Cleiton A Libardi
- MUSCULAB-Laboratory of Neuromuscular Adaptations to Resistance Training, Department of Physical Education, Federal University of São Carlos, São Carlos, Brazil
| | - Carlos Ugrinowitsch
- School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil
| | - Frank W Booth
- Department of Biomedical Sciences, University of Missouri, Columbia, Missouri, United States
| | - Karyn A Esser
- Department of Physiology and Aging, College of Medicine, University of Florida, Gainesville, Florida, United States
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15
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Leow BCS, Kok CH, Yeung DT, Hughes TP, White DL, Eadie LN. The acquisition order of leukemic drug resistance mutations is directed by the selective fitness associated with each resistance mechanism. Sci Rep 2023; 13:13110. [PMID: 37567965 PMCID: PMC10421868 DOI: 10.1038/s41598-023-40279-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 08/08/2023] [Indexed: 08/13/2023] Open
Abstract
In Chronic Myeloid Leukemia, the transition from drug sensitive to drug resistant disease is poorly understood. Here, we used exploratory sequencing of gene transcripts to determine the mechanisms of drug resistance in a dasatinib resistant cell line model. Importantly, cell samples were collected sequentially during drug exposure and dose escalation, revealing several resistance mechanisms which fluctuated over time. BCR::ABL1 overexpression, BCR::ABL1 kinase domain mutation, and overexpression of the small molecule transporter ABCG2, were identified as dasatinib resistance mechanisms. The acquisition of mutations followed an order corresponding with the increase in selective fitness associated with each resistance mechanism. Additionally, it was demonstrated that ABCG2 overexpression confers partial ponatinib resistance. The results of this study have broad applicability and help direct effective therapeutic drug usage and dosing regimens and may be useful for clinicians to select the most efficacious therapy at the most beneficial time.
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Affiliation(s)
- Benjamin C S Leow
- Blood Cancer Program, Precision Cancer Medicine Theme, South Australian Health & Medical Research Institute, Adelaide, SA, 5000, Australia
- Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA, 5000, Australia
| | - Chung H Kok
- Blood Cancer Program, Precision Cancer Medicine Theme, South Australian Health & Medical Research Institute, Adelaide, SA, 5000, Australia
- Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA, 5000, Australia
| | - David T Yeung
- Blood Cancer Program, Precision Cancer Medicine Theme, South Australian Health & Medical Research Institute, Adelaide, SA, 5000, Australia
- Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA, 5000, Australia
- Australasian Leukaemia & Lymphoma Group, Richmond, VIC, 3121, Australia
- Royal Adelaide Hospital, Adelaide, SA, 5000, Australia
| | - Timothy P Hughes
- Blood Cancer Program, Precision Cancer Medicine Theme, South Australian Health & Medical Research Institute, Adelaide, SA, 5000, Australia
- Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA, 5000, Australia
- Australasian Leukaemia & Lymphoma Group, Richmond, VIC, 3121, Australia
- Royal Adelaide Hospital, Adelaide, SA, 5000, Australia
| | - Deborah L White
- Blood Cancer Program, Precision Cancer Medicine Theme, South Australian Health & Medical Research Institute, Adelaide, SA, 5000, Australia
- Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA, 5000, Australia
- Australasian Leukaemia & Lymphoma Group, Richmond, VIC, 3121, Australia
- Australian & New Zealand Children's Haematology/Oncology Group, Clayton, VIC, 3168, Australia
- Australian Genomics Health Alliance, Parkville, VIC, 3052, Australia
| | - Laura N Eadie
- Blood Cancer Program, Precision Cancer Medicine Theme, South Australian Health & Medical Research Institute, Adelaide, SA, 5000, Australia.
- Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA, 5000, Australia.
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16
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Mori M, Cheng C, Taylor BR, Okano H, Hwa T. Functional decomposition of metabolism allows a system-level quantification of fluxes and protein allocation towards specific metabolic functions. Nat Commun 2023; 14:4161. [PMID: 37443156 PMCID: PMC10345195 DOI: 10.1038/s41467-023-39724-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 06/20/2023] [Indexed: 07/15/2023] Open
Abstract
Quantifying the contribution of individual molecular components to complex cellular processes is a grand challenge in systems biology. Here we establish a general theoretical framework (Functional Decomposition of Metabolism, FDM) to quantify the contribution of every metabolic reaction to metabolic functions, e.g. the synthesis of biomass building blocks. FDM allowed for a detailed quantification of the energy and biosynthesis budget for growing Escherichia coli cells. Surprisingly, the ATP generated during the biosynthesis of building blocks from glucose almost balances the demand from protein synthesis, the largest energy expenditure known for growing cells. This leaves the bulk of the energy generated by fermentation and respiration unaccounted for, thus challenging the common notion that energy is a key growth-limiting resource. Moreover, FDM together with proteomics enables the quantification of enzymes contributing towards each metabolic function, allowing for a first-principle formulation of a coarse-grained model of global protein allocation based on the structure of the metabolic network.
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Affiliation(s)
- Matteo Mori
- Department of Physics, University of California San Diego, 9500 Gilman Dr. La Jolla, San Diego, CA, 92093, USA.
| | - Chuankai Cheng
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, 90089, USA
| | - Brian R Taylor
- Department of Physics, University of California San Diego, 9500 Gilman Dr. La Jolla, San Diego, CA, 92093, USA
| | - Hiroyuki Okano
- Department of Physics, University of California San Diego, 9500 Gilman Dr. La Jolla, San Diego, CA, 92093, USA
| | - Terence Hwa
- Department of Physics, University of California San Diego, 9500 Gilman Dr. La Jolla, San Diego, CA, 92093, USA
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17
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Nascimento JF, Souza ROO, Alencar MB, Marsiccobetre S, Murillo AM, Damasceno FS, Girard RBMM, Marchese L, Luévano-Martinez LA, Achjian RW, Haanstra JR, Michels PAM, Silber AM. How much (ATP) does it cost to build a trypanosome? A theoretical study on the quantity of ATP needed to maintain and duplicate a bloodstream-form Trypanosoma brucei cell. PLoS Pathog 2023; 19:e1011522. [PMID: 37498954 PMCID: PMC10409291 DOI: 10.1371/journal.ppat.1011522] [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: 03/23/2023] [Revised: 08/08/2023] [Accepted: 06/29/2023] [Indexed: 07/29/2023] Open
Abstract
ATP hydrolysis is required for the synthesis, transport and polymerization of monomers for macromolecules as well as for the assembly of the latter into cellular structures. Other cellular processes not directly related to synthesis of biomass, such as maintenance of membrane potential and cellular shape, also require ATP. The unicellular flagellated parasite Trypanosoma brucei has a complex digenetic life cycle. The primary energy source for this parasite in its bloodstream form (BSF) is glucose, which is abundant in the host's bloodstream. Here, we made a detailed estimation of the energy budget during the BSF cell cycle. As glycolysis is the source of most produced ATP, we calculated that a single parasite produces 6.0 x 1011 molecules of ATP/cell cycle. Total biomass production (which involves biomass maintenance and duplication) accounts for ~63% of the total energy budget, while the total biomass duplication accounts for the remaining ~37% of the ATP consumption, with in both cases translation being the most expensive process. These values allowed us to estimate a theoretical YATP of 10.1 (g biomass)/mole ATP and a theoretical [Formula: see text] of 28.6 (g biomass)/mole ATP. Flagellar motility, variant surface glycoprotein recycling, transport and maintenance of transmembrane potential account for less than 30% of the consumed ATP. Finally, there is still ~5.5% available in the budget that is being used for other cellular processes of as yet unknown cost. These data put a new perspective on the assumptions about the relative energetic weight of the processes a BSF trypanosome undergoes during its cell cycle.
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Affiliation(s)
- Janaina F. Nascimento
- Laboratory of Biochemistry of Tryps–LaBTryps, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo–São Paulo, Brazil
| | - Rodolpho O. O. Souza
- Laboratory of Biochemistry of Tryps–LaBTryps, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo–São Paulo, Brazil
| | - Mayke B. Alencar
- Laboratory of Biochemistry of Tryps–LaBTryps, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo–São Paulo, Brazil
| | - Sabrina Marsiccobetre
- Laboratory of Biochemistry of Tryps–LaBTryps, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo–São Paulo, Brazil
| | - Ana M. Murillo
- Laboratory of Biochemistry of Tryps–LaBTryps, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo–São Paulo, Brazil
| | - Flávia S. Damasceno
- Laboratory of Biochemistry of Tryps–LaBTryps, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo–São Paulo, Brazil
| | - Richard B. M. M. Girard
- Laboratory of Biochemistry of Tryps–LaBTryps, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo–São Paulo, Brazil
| | - Letícia Marchese
- Laboratory of Biochemistry of Tryps–LaBTryps, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo–São Paulo, Brazil
| | - Luis A. Luévano-Martinez
- Laboratory of Biochemistry of Tryps–LaBTryps, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo–São Paulo, Brazil
| | - Renan W. Achjian
- Laboratory of Biochemistry of Tryps–LaBTryps, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo–São Paulo, Brazil
| | - Jurgen R. Haanstra
- Systems Biology Lab, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Paul A. M. Michels
- School of Biological Sciences, The University of Edinburgh, Edinburgh, United Kingdom
| | - Ariel M. Silber
- Laboratory of Biochemistry of Tryps–LaBTryps, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo–São Paulo, Brazil
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18
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Xie L, Alam MJ, Marques FZ, Mackay CR. A major mechanism for immunomodulation: Dietary fibres and acid metabolites. Semin Immunol 2023; 66:101737. [PMID: 36857894 DOI: 10.1016/j.smim.2023.101737] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 01/17/2023] [Accepted: 02/09/2023] [Indexed: 03/01/2023]
Abstract
Diet and the gut microbiota have a profound influence on physiology and health, however, mechanisms are still emerging. Here we outline several pathways that gut microbiota products, particularly short-chain fatty acids (SCFAs), use to maintain gut and immune homeostasis. Dietary fibre is fermented by the gut microbiota in the colon, and large quantities of SCFAs such as acetate, propionate, and butyrate are produced. Dietary fibre and SCFAs enhance epithelial integrity and thereby limit systemic endotoxemia. Moreover, SCFAs inhibit histone deacetylases (HDAC), and thereby affect gene transcription. SCFAs also bind to 'metabolite-sensing' G-protein coupled receptors (GPCRs) such as GPR43, which promotes immune homeostasis. The enormous amounts of SCFAs produced in the colon are sufficient to lower pH, which affects the function of proton sensors such as GPR65 expressed on the gut epithelium and immune cells. GPR65 is an anti-inflammatory Gαs-coupled receptor, which leads to the inhibition of inflammatory cytokines. The importance of GPR65 in inflammatory diseases is underscored by genetics associated with the missense variant I231L (rs3742704), which is associated with human inflammatory bowel disease, atopic dermatitis, and asthma. There is enormous scope to manipulate these pathways using specialized diets that release very high amounts of specific SCFAs in the gut, and we believe that therapies that rely on chemically modified foods is a promising approach. Such an approach includes high SCFA-producing diets, which we have shown to decrease numerous inflammatory western diseases in mouse models. These diets operate at many levels - increased gut integrity, changes to the gut microbiome, and promotion of immune homeostasis, which represents a new and highly promising way to prevent or treat human disease.
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Affiliation(s)
- Liang Xie
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia; Hypertension Research Laboratory, School of Biological Sciences, Monash University, Clayton, VIC 3800, Australia
| | - Md Jahangir Alam
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia
| | - Francine Z Marques
- Hypertension Research Laboratory, School of Biological Sciences, Monash University, Clayton, VIC 3800, Australia; Heart Failure Research Laboratory, Baker Heart and Diabetes Institute, Melbourne,VIC 3004, Australia
| | - Charles R Mackay
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia; School of Pharmaceutical Sciences, Shandong Analysis and Test Center, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250014, China.
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19
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Lennox-Hvenekilde D, Bali AP, Gronenberg LS, Acevedo-Rocha C, Sommer MOA, Genee HJ. Metabolic engineering of Escherichia coli for high-level production of free lipoic acid. Metab Eng 2023; 76:39-49. [PMID: 36639019 DOI: 10.1016/j.ymben.2023.01.004] [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: 09/26/2022] [Revised: 01/04/2023] [Accepted: 01/07/2023] [Indexed: 01/12/2023]
Abstract
L-Lipoic acid (LA) is an important antioxidant with various industrial applications as a nutraceutical and therapeutic. Currently, LA is produced by chemical synthesis. Cell factory development is complex as LA and its direct precursors only occur naturally in protein-bound forms. Here we report a rationally engineered LA cell factory and demonstrate de novo free LA production from glucose for the first time in E. coli. The pathway represents a significant challenge as the three key enzymes, native Octanoyltransferase (LipB) and Lipoyl Synthase (LipA), and heterologous Lipoamidase (LpA), are all toxic to overexpress in E. coli. To overcome the toxicity of LipB, functional metagenomic selection was used to identify a highly active and non-toxic LipB and LipA from S. liquefaciens. Using high throughput screening, we balanced translation initiation rates and dual, orthogonal induction systems for the toxic genes, LipA and LpA. The optimized strain yielded 2.5 mg free LA per gram of glucose in minimal media, expressing carefully balanced LipB and LipA, Enterococcus faecalis LpA, and a truncated, native, Dihydrolipoyllysine-residue acetyltransferase (AceF) lipoylation domain. When the optimized cell factory strain was cultivated in a fed-batch fermentation, a titer of 87 mg/L free LA in the supernatant was reached after 48 h. This titer is ∼3000-fold higher than previously reported free LA titer and ∼8-fold higher than the previous best total, protein-bound LA titer. The strategies presented here could be helpful in designing, constructing and balancing biosynthetic pathways that harbor toxic enzymes with protein-bound intermediates or products.
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Affiliation(s)
- David Lennox-Hvenekilde
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Kgs, Lyngby, Denmark; Biosyntia ApS, Fruebjergvej 3, 2100, Oesterbro, Denmark
| | - Anne P Bali
- Biosyntia ApS, Fruebjergvej 3, 2100, Oesterbro, Denmark
| | | | | | - Morten O A Sommer
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Kgs, Lyngby, Denmark
| | - Hans J Genee
- Biosyntia ApS, Fruebjergvej 3, 2100, Oesterbro, Denmark.
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20
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Effect of itaconic acid production on Neurospora crassa in consolidated bioprocessing of cellulose. Microb Cell Fact 2023; 22:28. [PMID: 36774527 PMCID: PMC9922455 DOI: 10.1186/s12934-023-02034-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2023] [Accepted: 02/03/2023] [Indexed: 02/13/2023] Open
Abstract
A system for itaconic acid synthesis from cellulose by Neurospora crassa was established, resulting in the highest yield of itaconic acid was 354.08 + 35.99 mg/L. Meanwhile, cellulase activity increased significantly, without any strain modifications for improved cellulase production. Multi-omics analyses showed that itaconic acid synthesis reduced energy production, leading to decreases in trehalose, cell wall, fatty acids synthesis and downregulations in MAPK signaling pathway, cell cycle and meiosis. More importantly, the low-energy environment enhanced the energy-efficient cellobionic acid/gluconic acid pathway, and the cellulase composition also changed significantly, manifested as the up-regulation of LPMOs and the down-regulation of β-glucosidases. Enhancing LPMOs-cellobionic acid/gluconic acid system has the potential to reduce energy consumption of the consolidated bioprocessing. These findings offer an overview of resource allocations by N. crassa in response to itaconic acid synthesis and highlight a series of intriguing connections between itaconic acid synthesis and cellulase synthesis in consolidated bioprocessing.
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21
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Le LQ, Zhu K, Su H. Bridging ribosomal synthesis to cell growth through the lens of kinetics. Biophys J 2023; 122:544-553. [PMID: 36564946 PMCID: PMC9941725 DOI: 10.1016/j.bpj.2022.12.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 07/20/2022] [Accepted: 12/19/2022] [Indexed: 12/24/2022] Open
Abstract
Understanding prokaryotic cell growth requires a multiscale modeling framework from the kinetics perspective. The detailed kinetics pathway of ribosomes exhibits features beyond the scope of the classical Hopfield kinetics model. The complexity of the molecular responses to various nutrient conditions poses additional challenge to elucidate the cell growth. Herein, a kinetics framework is developed to bridge ribosomal synthesis to cell growth. For the ribosomal synthesis kinetics, the competitive binding between cognate and near-cognate tRNAs for ribosomes can be modulated by Mg2+. This results in distinct patterns of the speed - accuracy relation comprising "trade-off" and "competition" regimes. Furthermore, the cell growth rate is optimized by varying the characteristics of ribosomal synthesis through cellular responses to different nutrient conditions. In this scenario, cellular responses to nutrient conditions manifest by two quadratic scaling relations: one for nutrient flux versus cell mass, the other for ribosomal number versus growth rate. Both are in quantitative agreement with experimental measurements.
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Affiliation(s)
- Luan Quang Le
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore; Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
| | - Kaicheng Zhu
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
| | - Haibin Su
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
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22
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Kim H, Mori Y, Plotkin JB. Optimality of intercellular signaling: Direct transport versus diffusion. Phys Rev E 2022; 106:054411. [PMID: 36559352 DOI: 10.1103/physreve.106.054411] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 10/28/2022] [Indexed: 06/17/2023]
Abstract
Intercellular signaling has an important role in organism development, but not all communication occurs using the same mechanism. Here, we analyze the energy efficiency of intercellular signaling by two canonical mechanisms: Diffusion of signaling molecules and direct transport mediated by signaling cellular protrusions. We show that efficient contact formation for direct transport can be established by an optimal rate of projecting protrusions, which depends on the availability of information about the location of the target cell. The optimal projection rate also depends on how signaling molecules are transported along the protrusion, in particular the ratio of the energy cost for contact formation and molecule synthesis. Also, we compare the efficiency of the two signaling mechanisms, under various model parameters. We find that direct transport is favored over diffusion when transporting a large amount of signaling molecules. There is a critical number of signaling molecules at which the efficiencies of the two mechanisms are the same. The critical number is small when the distance between cells is far, which helps explain why protrusion-based mechanisms are observed in long-range cellular communications.
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Affiliation(s)
- Hyunjoong Kim
- Center for Mathematical Biology and Department of Mathematics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Yoichiro Mori
- Center for Mathematical Biology and Department of Mathematics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Joshua B Plotkin
- Center for Mathematical Biology and Department of Mathematics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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23
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Guan X, Erşan S, Hu X, Atallah TL, Xie Y, Lu S, Cao B, Sun J, Wu K, Huang Y, Duan X, Caram JR, Yu Y, Park JO, Liu C. Maximizing light-driven CO 2 and N 2 fixation efficiency in quantum dot-bacteria hybrids. Nat Catal 2022; 5:1019-1029. [PMID: 36844635 PMCID: PMC9956923 DOI: 10.1038/s41929-022-00867-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 09/30/2022] [Indexed: 11/11/2022]
Abstract
Integrating light-harvesting materials with microbial biochemistry is a viable approach to produce chemicals with high efficiency from the air, water, and sunlight. Yet it remains unclear whether all absorbed photons in the materials can be transferred through the material-biology interface for solar-to-chemical production and whether the presence of materials beneficially affect the microbial metabolism. Here we report a microbe-semiconductor hybrid by interfacing CO2/N2-fixing bacterium Xanthobacter autotrophicus with CdTe quantum dots for light-driven CO2 and N2 fixation with internal quantum efficiencies of 47.2 ± 7.3% and 7.1 ± 1.1%, respectively, reaching the biochemical limits of 46.1% and 6.9% imposed by the stoichiometry in biochemical pathways. Photophysical studies suggest fast charge-transfer kinetics at the microbe-semiconductor interfaces, while proteomics and metabolomics indicate a material-induced regulation of microbial metabolism favoring higher quantum efficiencies compared to the biological counterparts alone.
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Affiliation(s)
- Xun Guan
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095, United States
| | - Sevcan Erşan
- Department of Chemical and Biomolecular Engineering, University of California Los Angeles, Los Angeles, California 90095, United States
| | - Xiangchen Hu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Timothy L. Atallah
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095, United States
- Department of Chemistry and Biochemistry, Denison University, Granville, Ohio 43023, United States
| | - Yongchao Xie
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095, United States
| | - Shengtao Lu
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095, United States
| | - Bocheng Cao
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095, United States
- Department of Materials Science and Engineering, University of California Los Angeles, Los Angeles, California 90095, United States
| | - Jingwen Sun
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095, United States
| | - Ke Wu
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095, United States
| | - Yu Huang
- Department of Materials Science and Engineering, University of California Los Angeles, Los Angeles, California 90095, United States
- California NanoSystems Institute, University of California Los Angeles, Los Angeles, California 90095, United States
| | - Xiangfeng Duan
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095, United States
- California NanoSystems Institute, University of California Los Angeles, Los Angeles, California 90095, United States
| | - Justin R. Caram
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095, United States
| | - Yi Yu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Junyoung O. Park
- Department of Chemical and Biomolecular Engineering, University of California Los Angeles, Los Angeles, California 90095, United States
| | - Chong Liu
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095, United States
- California NanoSystems Institute, University of California Los Angeles, Los Angeles, California 90095, United States
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24
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Spatial transcriptome profiling of normal human liver. Sci Data 2022; 9:633. [PMID: 36261431 PMCID: PMC9581974 DOI: 10.1038/s41597-022-01676-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: 04/01/2022] [Accepted: 09/05/2022] [Indexed: 11/21/2022] Open
Abstract
The comprehensive study of the spatial-cellular anatomy of the human liver is critical to addressing the cellular origins of liver disease. Here we conducted spatial transcriptomics on normal human liver tissue sections, providing detailed information of liver zonation at the transcriptional level. We present 6581 high-quality spots from normal livers of two human donors. In this dataset, cells were mainly hepatocytes, and we classified them into four sub-groups. Collectively, these data provide a reliable reference for studies on spatial heterogeneity of liver lobules. Measurement(s) | mRNA Expression | Technology Type(s) | spatial transcriptomics | Sample Characteristic - Organism | Homo sapiens |
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25
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Abstract
Since Jacques Monod's foundational work in the 1940s, investigators studying bacterial physiology have largely (but not exclusively) focused on the exponential phase of bacterial cultures, which is characterized by rapid growth and high biosynthesis activity in the presence of excess nutrients. However, this is not the predominant state of bacterial life. In nature, most bacteria experience nutrient limitation most of the time. In fact, investigators even prior to Monod had identified other aspects of bacterial growth, including what is now known as the stationary phase, when nutrients become limiting. This review will discuss how bacteria transition to growth arrest in response to nutrient limitation through changes in transcription, translation, and metabolism. We will then examine how these changes facilitate survival during potentially extended periods of nutrient limitation, with particular attention to the metabolic strategies that underpin bacterial longevity in this state.
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Affiliation(s)
- Jonathan Dworkin
- Department of Microbiology and Immunology, College of Physicians and Surgeons, Columbia University, New York, NY, USA;
| | - Caroline S Harwood
- Department of Microbiology, University of Washington, Seattle, Washington, USA;
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26
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Nonlinear multi-objective flux balance analysis of the Warburg Effect. J Theor Biol 2022; 550:111223. [PMID: 35853493 DOI: 10.1016/j.jtbi.2022.111223] [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: 01/06/2022] [Revised: 05/28/2022] [Accepted: 07/12/2022] [Indexed: 11/20/2022]
Abstract
Due to its implication in cancer treatment, the Warburg Effect has received extensive in silico investigation. Flux Balance Analysis (FBA), based on constrained optimization, was successfully applied in the Warburg Effect modelling. Yet, the assumption that cell types have one invariant cellular objective severely limits the applicability of the previous FBA models. Meanwhile, we note that cell types with different objectives show different extents of the Warburg Effect. To extend the applicability of the previous model and model the disparate cellular pathway preferences in different cell types, we built a Nonlinear Multi-Objective FBA (NLMOFBA) model by including three key objective terms (ATP production rate, lactate generation rate and ATP yield) into one objective function through linear scalarization. By constructing a cellular objective map and iteratively varying the objective weights, we showed disparate cellular pathway preferences manifested by different cell types driven by their unique cellular objectives, and we gained insights about the causal relationship between cellular objectives and the Warburg Effect. In addition, we obtained other biologically consistent results by using our NLMOFBA model. For example, augmented with the constraint associated with inefficient mitochondria function, low oxygen availability, or limited substrate, NLMOFBA predicts cellular pathways supported by the biology literature. Collectively, our NLMOFBA model can help build a complete understanding towards the Warburg Effect in different cell types. Finally, we investigated the impact of glutaminolysis, an important pathway related to glycolysis, on the occurrence of the Warburg Effect by using linear programming.
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27
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Smith DA, Nakamoto BJ, Suess MK, Fogel ML. Central Metabolism and Growth Rate Impacts on Hydrogen and Carbon Isotope Fractionation During Amino Acid Synthesis in E. coli. Front Microbiol 2022; 13:840167. [PMID: 35910622 PMCID: PMC9335129 DOI: 10.3389/fmicb.2022.840167] [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: 12/20/2021] [Accepted: 06/22/2022] [Indexed: 11/20/2022] Open
Abstract
Compound specific stable isotope analysis (CSIA) of amino acids from bacterial biomass is a newly emerging powerful tool for exploring central carbon metabolism pathways and fluxes. By comparing isotopic values and fractionations relative to water and growth substrate, the impact of variable flow path for metabolites through different central metabolic pathways, perturbations of these paths, and their resultant consequences on intracellular pools and resultant biomass may be elucidated. Here, we explore the effects that central carbon metabolism and growth rate can have on stable hydrogen (δ2H) and carbon (δ13C) compound specific isotopic values of amino acids, and whether diagnostic isotopic fingerprints are revealed by these paired analyses. We measured δ2H and δ13C in amino acids in the wild type Escherichia coli (MG1655) across a range of growth rates in chemostat cultures to address the unknown isotopic consequences as metabolic fluxes are shuffled between catabolic and anabolic metabolisms. Additionally, two E. coli knockout mutants, one with deficiency in glycolysis –pgi (LC1888) and another inhibiting the oxidative pentose phosphate pathway (OPPP) –zwf (LC1889), were grown on glucose and used as a comparison against the wild type E. coli (MG1655) to address the isotopic changes of amino acids produced in these perturbed metabolic pathways. Amino acid δ2H values, which collectively vary in composition by more than 400‰, are altered along with δ13C values demonstrating fundamental shifts in central metabolic pathways and/or fluxes. Within our linear discriminant analysis with a simple model organism to examine potential amino acid fingerprinting, our knockout strains and variable growth rate samples plot across a wider array of organism classification than merely within the boundaries of other bacterial data.
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Affiliation(s)
- Derek A. Smith
- Department of Biology, Case Western Reserve University, Cleveland, OH, United States
- *Correspondence: Derek A. Smith
| | - Bobby James Nakamoto
- Department of Biology, University of New Brunswick Fredericton, Fredericton, NB, Canada
- Department of Earth and Planetary Sciences, EDGE Institute, University of California, Riverside, Riverside, CA, United States
| | - Melanie K. Suess
- Department of Earth and Planetary Sciences, Washington University in St. Louis, St. Louis, MO, United States
| | - Marilyn L. Fogel
- Department of Earth and Planetary Sciences, EDGE Institute, University of California, Riverside, Riverside, CA, United States
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28
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Abstract
Changes in the composition of the gut microbiota are associated with many human diseases. So far, however, we have failed to define homeostasis or dysbiosis by the presence or absence of specific microbial species. The composition and function of the adult gut microbiota is governed by diet and host factors that regulate and direct microbial growth. The host delivers oxygen and nitrate to the lumen of the small intestine, which selects for bacteria that use respiration for energy production. In the colon, by contrast, the host limits the availability of oxygen and nitrate, which results in a bacterial community that specializes in fermentation for growth. Although diet influences microbiota composition, a poor diet weakens host control mechanisms that regulate the microbiota. Hence, quantifying host parameters that control microbial growth could help define homeostasis or dysbiosis and could offer alternative strategies to remediate dysbiosis.
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Affiliation(s)
- Jee-Yon Lee
- Department of Medical Microbiology and Immunology, School of Medicine, University of California at Davis, Davis, CA 95616, USA
| | - Renée M Tsolis
- Department of Medical Microbiology and Immunology, School of Medicine, University of California at Davis, Davis, CA 95616, USA
| | - Andreas J Bäumler
- Department of Medical Microbiology and Immunology, School of Medicine, University of California at Davis, Davis, CA 95616, USA
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29
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Söllinger A, Séneca J, Borg Dahl M, Motleleng LL, Prommer J, Verbruggen E, Sigurdsson BD, Janssens I, Peñuelas J, Urich T, Richter A, Tveit AT. Down-regulation of the bacterial protein biosynthesis machinery in response to weeks, years, and decades of soil warming. SCIENCE ADVANCES 2022; 8:eabm3230. [PMID: 35333567 PMCID: PMC8956259 DOI: 10.1126/sciadv.abm3230] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 02/03/2022] [Indexed: 05/26/2023]
Abstract
How soil microorganisms respond to global warming is key to infer future soil-climate feedbacks, yet poorly understood. Here, we applied metatranscriptomics to investigate microbial physiological responses to medium-term (8 years) and long-term (>50 years) subarctic grassland soil warming of +6°C. Besides indications for a community-wide up-regulation of centralmetabolic pathways and cell replication, we observed a down-regulation of the bacterial protein biosynthesis machinery in the warmed soils, coinciding with a lower microbial biomass, RNA, and soil substrate content. We conclude that permanently accelerated reaction rates at higher temperatures and reduced substrate concentrations result in cellular reduction of ribosomes, the macromolecular complexes carrying out protein biosynthesis. Later efforts to test this, including a short-term warming experiment (6 weeks, +6°C), further supported our conclusion. Down-regulating the protein biosynthesis machinery liberates energy and matter, allowing soil bacteria to maintain high metabolic activities and cell division rates even after decades of warming.
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Affiliation(s)
- Andrea Söllinger
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø, Norway
| | - Joana Séneca
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | - Mathilde Borg Dahl
- Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Liabo L. Motleleng
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø, Norway
| | - Judith Prommer
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | | | | | | | - Josep Peñuelas
- CSIC, Global Ecology Unit CREAF-CSIC-UAB, Barcelona, Spain
- CREAF, Barcelona, Spain
| | - Tim Urich
- Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Andreas Richter
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | - Alexander T. Tveit
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø, Norway
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30
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Developmental energetics: Energy expenditure, budgets and metabolism during animal embryogenesis. Semin Cell Dev Biol 2022; 138:83-93. [PMID: 35317962 DOI: 10.1016/j.semcdb.2022.03.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 02/07/2022] [Accepted: 03/05/2022] [Indexed: 11/22/2022]
Abstract
Developing embryos are metabolically active, open systems that constantly exchange matter and energy with their environment. They function out of thermodynamic equilibrium and continuously use metabolic pathways to obtain energy from maternal nutrients, in order to fulfill the energetic requirements of growth and development. While an increasing number of studies highlight the role of metabolism in different developmental contexts, the physicochemical basis of embryogenesis, or how cellular processes use energy and matter to act together and transform a zygote into an adult organism, remains unknown. As we obtain a better understanding of metabolism, and benefit from current technology development, it is a promising time to revisit the energetic cost of development and how energetic principles may govern embryogenesis. Here, we review recent advances in methodology to measure and infer energetic parameters in developing embryos. We highlight a potential common pattern in embryonic energy expenditure and metabolic strategy across animal embryogenesis, and discuss challenges and open questions in developmental energetics.
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31
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Coordination of Phosphate and Magnesium Metabolism in Bacteria. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1362:135-150. [PMID: 35288878 DOI: 10.1007/978-3-030-91623-7_12] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The majority of cellular phosphate (PO4-3; Pi) exists as nucleoside triphosphates, mainly adenosine triphosphate (ATP), and ribosomal RNA (rRNA). ATP and rRNA are also the largest cytoplasmic reservoirs of magnesium (Mg2+), the most abundant divalent cation in living cells. The co-occurrence of these ionic species in the cytoplasm is not coincidental. Decades of work in the Pi and Mg2+ starvation responses of two model enteric bacteria, Escherichia coli and Salmonella enterica, have led to the realization that the metabolisms of Pi and Mg2+ are interconnected. Bacteria must acquire these nutrients in a coordinated manner to achieve balanced growth and avoid loss of viability. In this chapter, we will review how bacteria sense and respond to fluctuations in environmental and intracellular Pi and Mg2+ levels. We will also discuss how these two compounds are functionally linked, and how cells elicit physiological responses to maintain their homeostasis.
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32
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Meranti (Shorea sp.) Biochar Application Method on the Growth of Sengon (Falcataria moluccana) as a Solution of Phosphorus Crisis. ENERGIES 2022. [DOI: 10.3390/en15062110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Phosphorus (P) is a limiting nutrient mined from non-renewable sources. P is needed to stimulate trees growth in a forest plantation. P-fertilizer addition in the tropical forest field causes P-leaching flux to watershed and induces eutrophication. The high C contained in meranti (Shorea sp.) biochar can avoid the P-leaching process in the soil with a strategic application method. However, the biochar application method is poorly examined. This research aimed to develop a biochar application method to sequestrate P from the environment and examine its effect on the growth of sengon (Falcataria moluccana). Shorea sp. biochar pyrolyzed at 400 °C and 600 °C were added at a dosage of 0 t ha−1, 25 t ha−1, and 50 t ha−1 for six months in the field. The biochar was placed 20 cm under topsoil without soil mixing. This application method significantly increased total P in the soil without any P-fertilizer addition. The results showed that biochar pyrolyzed at 600 °C and a dosage of 25 t ha−1 increased the total P in the soil and CEC by 192.2 mg kg−1 and 25.98 me 100 g−1, respectively. Biochar with a higher pyrolysis temperature increased higher soil pH. In contrast, the higher dosage increased organic-C higher than the lower dosage application. The most significant P-uptake, height, and diameter increments on F.moluccana were achieved using Shorea sp. biochar pyrolyzed at 600 °C with a dosage of 25 t ha−1 by 0.42 mg kg−1, 222 cm, and 2.75 cm, respectively. The total P in the soil positively correlated with the P-uptake of F. moluccana. Furthermore, using the biochar application method P could be absorbed to the biochar layer and desorbed to the topsoil. Consequently, the biochar application method together with P-fertilizer addition could increase the availability of P in the soil and decrease P-leaching to the environment.
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33
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Lobritz MA, Andrews IW, Braff D, Porter CBM, Gutierrez A, Furuta Y, Cortes LBG, Ferrante T, Bening SC, Wong F, Gruber C, Bakerlee C, Lambert G, Walker GC, Dwyer DJ, Collins JJ. Increased energy demand from anabolic-catabolic processes drives β-lactam antibiotic lethality. Cell Chem Biol 2022; 29:276-286.e4. [PMID: 34990601 PMCID: PMC8857051 DOI: 10.1016/j.chembiol.2021.12.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 10/11/2021] [Accepted: 12/06/2021] [Indexed: 12/22/2022]
Abstract
β-Lactam antibiotics disrupt the assembly of peptidoglycan (PG) within the bacterial cell wall by inhibiting the enzymatic activity of penicillin-binding proteins (PBPs). It was recently shown that β-lactam treatment initializes a futile cycle of PG synthesis and degradation, highlighting major gaps in our understanding of the lethal effects of PBP inhibition by β-lactam antibiotics. Here, we assess the downstream metabolic consequences of treatment of Escherichia coli with the β-lactam mecillinam and show that lethality from PBP2 inhibition is a specific consequence of toxic metabolic shifts induced by energy demand from multiple catabolic and anabolic processes, including accelerated protein synthesis downstream of PG futile cycling. Resource allocation into these processes is coincident with alterations in ATP synthesis and utilization, as well as a broadly dysregulated cellular redox environment. These results indicate that the disruption of normal anabolic-catabolic homeostasis by PBP inhibition is an essential factor for β-lactam antibiotic lethality.
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Affiliation(s)
- Michael A. Lobritz
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115, USA,Institute for Medical Engineering & Science, Department of Biological Engineering, and Synthetic Biology Center, Massachusetts Institute of Technology, Cambridge, MA 02139, USA,Broad Institute of MIT and Harvard, Cambridge, MA 02139, USA,Division of Infectious Diseases, Massachusetts General Hospital, Boston, MA 02114, USA,Present address: Roche Pharma Research and Early Development, Roche Innovation Center Basel, 4070 Basel, Switzerland,These authors contributed equally
| | - Ian W. Andrews
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115, USA,Institute for Medical Engineering & Science, Department of Biological Engineering, and Synthetic Biology Center, Massachusetts Institute of Technology, Cambridge, MA 02139, USA,Broad Institute of MIT and Harvard, Cambridge, MA 02139, USA,These authors contributed equally
| | - Dana Braff
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115, USA,Institute for Medical Engineering & Science, Department of Biological Engineering, and Synthetic Biology Center, Massachusetts Institute of Technology, Cambridge, MA 02139, USA,Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA,Present address: GRO Biosciences, Cambridge, MA 02139, USA
| | - Caroline B. M. Porter
- Institute for Medical Engineering & Science, Department of Biological Engineering, and Synthetic Biology Center, Massachusetts Institute of Technology, Cambridge, MA 02139, USA,Broad Institute of MIT and Harvard, Cambridge, MA 02139, USA
| | - Arnaud Gutierrez
- Institute for Medical Engineering & Science, Department of Biological Engineering, and Synthetic Biology Center, Massachusetts Institute of Technology, Cambridge, MA 02139, USA,Broad Institute of MIT and Harvard, Cambridge, MA 02139, USA,Present address: Institut Cochin, INSERM U1016 – CNRS UMR8104 – Université Paris Descartes, 75014 Paris, France
| | - Yoshikazu Furuta
- Institute for Medical Engineering & Science, Department of Biological Engineering, and Synthetic Biology Center, Massachusetts Institute of Technology, Cambridge, MA 02139, USA,Present address: Research Center for Zoonosis Control, Hokkaido University, Sapporo 001-0020, Japan
| | - Louis B. G. Cortes
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY 14853, USA
| | - Thomas Ferrante
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115, USA
| | - Sarah C. Bening
- Institute for Medical Engineering & Science, Department of Biological Engineering, and Synthetic Biology Center, Massachusetts Institute of Technology, Cambridge, MA 02139, USA,Broad Institute of MIT and Harvard, Cambridge, MA 02139, USA
| | - Felix Wong
- Institute for Medical Engineering & Science, Department of Biological Engineering, and Synthetic Biology Center, Massachusetts Institute of Technology, Cambridge, MA 02139, USA,Broad Institute of MIT and Harvard, Cambridge, MA 02139, USA
| | - Charley Gruber
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Chris Bakerlee
- Institute for Medical Engineering & Science, Department of Biological Engineering, and Synthetic Biology Center, Massachusetts Institute of Technology, Cambridge, MA 02139, USA,Broad Institute of MIT and Harvard, Cambridge, MA 02139, USA
| | - Guillaume Lambert
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY 14853, USA
| | - Graham C. Walker
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Daniel J. Dwyer
- Department of Cell Biology and Molecular Genetics, Institute for Physical Science and Technology, Department of Biomedical Engineering, and Maryland Pathogen Research Institute, University of Maryland, College Park, MD 20742, USA,Corresponding authors: ,
| | - James J. Collins
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115, USA,Institute for Medical Engineering & Science, Department of Biological Engineering, and Synthetic Biology Center, Massachusetts Institute of Technology, Cambridge, MA 02139, USA,Broad Institute of MIT and Harvard, Cambridge, MA 02139, USA,Harvard-MIT Program in Health Sciences and Technology, Cambridge, MA 02139, USA,Lead contact,Corresponding authors: ,
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34
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Aye IL, Aiken CE, Charnock-Jones DS, Smith GC. Placental energy metabolism in health and disease-significance of development and implications for preeclampsia. Am J Obstet Gynecol 2022; 226:S928-S944. [PMID: 33189710 DOI: 10.1016/j.ajog.2020.11.005] [Citation(s) in RCA: 44] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 11/02/2020] [Accepted: 11/03/2020] [Indexed: 02/08/2023]
Abstract
The placenta is a highly metabolically active organ fulfilling the bioenergetic and biosynthetic needs to support its own rapid growth and that of the fetus. Placental metabolic dysfunction is a common occurrence in preeclampsia although its causal relationship to the pathophysiology is unclear. At the outset, this may simply be seen as an "engine out of fuel." However, placental metabolism plays a vital role beyond energy production and is linked to physiological and developmental processes. In this review, we discuss the metabolic basis for placental dysfunction and propose that the alterations in energy metabolism may explain many of the placental phenotypes of preeclampsia such as reduced placental and fetal growth, redox imbalance, oxidative stress, altered epigenetic and gene expression profiles, and the functional consequences of these aberrations. We propose that placental metabolic reprogramming reflects the dynamic physiological state allowing the tissue to adapt to developmental changes and respond to preeclampsia stress, whereas the inability to reprogram placental metabolism may result in severe preeclampsia phenotypes. Finally, we discuss common tested and novel therapeutic strategies for treating placental dysfunction in preeclampsia and their impact on placental energy metabolism as possible explanations into their potential benefits or harm.
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35
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Thornburg ZR, Bianchi DM, Brier TA, Gilbert BR, Earnest TM, Melo MC, Safronova N, Sáenz JP, Cook AT, Wise KS, Hutchison CA, Smith HO, Glass JI, Luthey-Schulten Z. Fundamental behaviors emerge from simulations of a living minimal cell. Cell 2022; 185:345-360.e28. [PMID: 35063075 PMCID: PMC9985924 DOI: 10.1016/j.cell.2021.12.025] [Citation(s) in RCA: 60] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 11/01/2021] [Accepted: 12/17/2021] [Indexed: 01/18/2023]
Abstract
We present a whole-cell fully dynamical kinetic model (WCM) of JCVI-syn3A, a minimal cell with a reduced genome of 493 genes that has retained few regulatory proteins or small RNAs. Cryo-electron tomograms provide the cell geometry and ribosome distributions. Time-dependent behaviors of concentrations and reaction fluxes from stochastic-deterministic simulations over a cell cycle reveal how the cell balances demands of its metabolism, genetic information processes, and growth, and offer insight into the principles of life for this minimal cell. The energy economy of each process including active transport of amino acids, nucleosides, and ions is analyzed. WCM reveals how emergent imbalances lead to slowdowns in the rates of transcription and translation. Integration of experimental data is critical in building a kinetic model from which emerges a genome-wide distribution of mRNA half-lives, multiple DNA replication events that can be compared to qPCR results, and the experimentally observed doubling behavior.
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Affiliation(s)
- Zane R. Thornburg
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - David M. Bianchi
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Troy A. Brier
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Benjamin R. Gilbert
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Tyler M. Earnest
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Marcelo C.R. Melo
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Nataliya Safronova
- Technische Universität Dresden, B CUBE Center for Molecular Bioengineering, 01307 Dresden, Germany
| | - James P. Sáenz
- Technische Universität Dresden, B CUBE Center for Molecular Bioengineering, 01307 Dresden, Germany
| | | | - Kim S. Wise
- J. Craig Venter Institute, La Jolla, CA 92037, USA
| | | | | | | | - Zaida Luthey-Schulten
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; NSF Center for the Physics of Living Cells, Urbana, IL 61801, USA; NIH Center for Macromolecular Modeling and Bioinformatics, Urbana, IL 61801, USA.
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Piatek P, Humphreys C, Raut MP, Wright PC, Simpson S, Köpke M, Minton NP, Winzer K. Agr Quorum Sensing influences the Wood-Ljungdahl pathway in Clostridium autoethanogenum. Sci Rep 2022; 12:411. [PMID: 35013405 PMCID: PMC8748961 DOI: 10.1038/s41598-021-03999-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 12/07/2021] [Indexed: 01/04/2023] Open
Abstract
Acetogenic bacteria are capable of fermenting CO2 and carbon monoxide containing waste-gases into a range of platform chemicals and fuels. Despite major advances in genetic engineering and improving these biocatalysts, several important physiological functions remain elusive. Among these is quorum sensing, a bacterial communication mechanism known to coordinate gene expression in response to cell population density. Two putative agr systems have been identified in the genome of Clostridium autoethanogenum suggesting bacterial communication via autoinducing signal molecules. Signal molecule-encoding agrD1 and agrD2 genes were targeted for in-frame deletion. During heterotrophic growth on fructose as a carbon and energy source, single deletions of either gene did not produce an observable phenotype. However, when both genes were simultaneously inactivated, final product concentrations in the double mutant shifted to a 1.5:1 ratio of ethanol:acetate, compared to a 0.2:1 ratio observed in the wild type control, making ethanol the dominant fermentation product. Moreover, CO2 re-assimilation was also notably reduced in both hetero- and autotrophic growth conditions. These findings were supported through comparative proteomics, which showed lower expression of carbon monoxide dehydrogenase, formate dehydrogenase A and hydrogenases in the ∆agrD1∆agrD2 double mutant, but higher levels of putative alcohol and aldehyde dehydrogenases and bacterial micro-compartment proteins. These findings suggest that Agr quorum sensing, and by inference, cell density play a role in carbon resource management and use of the Wood-Ljungdahl pathway as an electron sink.
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Affiliation(s)
- Pawel Piatek
- Department of Biotechnology and Nanomedicine, SINTEF Industry, 7465, Trondheim, Norway
- BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences, University Park, The University of Nottingham, Nottingham, UK
| | - Christopher Humphreys
- BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences, University Park, The University of Nottingham, Nottingham, UK
| | - Mahendra P Raut
- Department of Chemical and Biological Engineering, The ChELSI Institute, University of Sheffield, Mappin Street, Sheffield, S1 3JD, UK
| | - Phillip C Wright
- University of Southampton, University Road, Southampton, SO17 1BJ, UK
| | - Sean Simpson
- LanzaTech Inc., 8045 Lamon Ave, Suite 400, Skokie, IL, 60077, USA
| | - Michael Köpke
- LanzaTech Inc., 8045 Lamon Ave, Suite 400, Skokie, IL, 60077, USA
| | - Nigel P Minton
- BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences, University Park, The University of Nottingham, Nottingham, UK
| | - Klaus Winzer
- BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences, University Park, The University of Nottingham, Nottingham, UK.
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Pavan M, Reinmets K, Garg S, Mueller AP, Marcellin E, Köpke M, Valgepea K. Advances in systems metabolic engineering of autotrophic carbon oxide-fixing biocatalysts towards a circular economy. Metab Eng 2022; 71:117-141. [DOI: 10.1016/j.ymben.2022.01.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 01/24/2022] [Accepted: 01/25/2022] [Indexed: 12/16/2022]
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Wilkes RA, Waldbauer J, Aristilde L. Analogous Metabolic Decoupling in Pseudomonas putida and Comamonas testosteroni Implies Energetic Bypass to Facilitate Gluconeogenic Growth. mBio 2021; 12:e0325921. [PMID: 34903058 PMCID: PMC8669468 DOI: 10.1128/mbio.03259-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 11/04/2021] [Indexed: 11/30/2022] Open
Abstract
Gluconeogenic carbon metabolism is not well understood, especially within the context of flux partitioning between energy generation and biomass production, despite the importance of gluconeogenic carbon substrates in natural and engineered carbon processing. Here, using multiple omics approaches, we elucidate the metabolic mechanisms that facilitate gluconeogenic fast-growth phenotypes in Pseudomonas putida and Comamonas testosteroni, two Proteobacteria species with distinct metabolic networks. In contrast to the genetic constraint of C. testosteroni, which lacks the enzymes required for both sugar uptake and a complete oxidative pentose phosphate (PP) pathway, sugar metabolism in P. putida is known to generate surplus NADPH by relying on the oxidative PP pathway within its characteristic cyclic connection between the Entner-Doudoroff (ED) and Embden-Meyerhoff-Parnas (EMP) pathways. Remarkably, similar to the genome-based metabolic decoupling in C. testosteroni, our 13C-fluxomics reveals an inactive oxidative PP pathway and disconnected EMP and ED pathways in P. putida during gluconeogenic feeding, thus requiring transhydrogenase reactions to supply NADPH for anabolism in both species by leveraging the high tricarboxylic acid cycle flux during gluconeogenic growth. Furthermore, metabolomics and proteomics analyses of both species during gluconeogenic feeding, relative to glycolytic feeding, demonstrate a 5-fold depletion in phosphorylated metabolites and the absence of or up to a 17-fold decrease in proteins of the PP and ED pathways. Such metabolic remodeling, which is reportedly lacking in Escherichia coli exhibiting a gluconeogenic slow-growth phenotype, may serve to minimize futile carbon cycling while favoring the gluconeogenic metabolic regime in relevant proteobacterial species. IMPORTANCE Glycolytic metabolism of sugars is extensively studied in the Proteobacteria, but gluconeogenic carbon sources (e.g., organic acids, amino acids, aromatics) that feed into the tricarboxylic acid (TCA) cycle are widely reported to produce a fast-growth phenotype, particularly in species with biotechnological relevance. Much remains unknown about the importance of glycolysis-associated pathways in the metabolism of gluconeogenic carbon substrates. Here, we demonstrate that two distinct proteobacterial species, through genetic constraints or metabolic regulation at specific metabolic nodes, bypass the oxidative PP pathway during gluconeogenic growth and avoid unnecessary carbon fluxes by depleting protein investment into connected glycolysis pathways. Both species can leverage instead the high TCA cycle flux during gluconeogenic feeding to meet NADPH demand. Importantly, lack of a complete oxidative pentose phosphate pathway is a widespread metabolic trait in Proteobacteria with a gluconeogenic carbon preference, thus highlighting the important relevance of our findings toward elucidating the metabolic architecture in these bacteria.
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Affiliation(s)
- Rebecca A. Wilkes
- Department of Biological and Environmental Engineering, Cornell University, Ithaca, New York, USA
- Department of Civil and Environmental Engineering, Northwestern University, Evanston, Illinois, USA
| | - Jacob Waldbauer
- Department of the Geophysical Sciences, University of Chicago, Chicago, Illinois, USA
| | - Ludmilla Aristilde
- Department of Biological and Environmental Engineering, Cornell University, Ithaca, New York, USA
- Department of Civil and Environmental Engineering, Northwestern University, Evanston, Illinois, USA
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Exploiting Aerobic Carboxydotrophic Bacteria for Industrial Biotechnology. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2021; 180:1-32. [PMID: 34894287 DOI: 10.1007/10_2021_178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Aerobic carboxydotrophic bacteria are a group of microorganisms which possess the unique trait to oxidize carbon monoxide (CO) as sole energy source with molecular oxygen (O2) to produce carbon dioxide (CO2) which subsequently is used for biomass formation via the Calvin-Benson-Bassham cycle. Moreover, most carboxydotrophs are also able to oxidize hydrogen (H2) with hydrogenases to drive the reduction of carbon dioxide in the absence of CO. As several abundant industrial off-gases contain significant amounts of CO, CO2, H2 as well as O2, these bacteria come into focus for industrial application to produce chemicals and fuels from such gases in gas fermentation approaches. Since the group of carboxydotrophic bacteria is rather unknown and not very well investigated, we will provide an overview about their lifestyle and the underlying metabolic characteristics, introduce promising members for industrial application, and give an overview of available genetic engineering tools. We will point to limitations and discuss challenges, which have to be overcome to apply metabolic engineering approaches and to utilize aerobic carboxydotrophs in the industrial environment.
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Xu J, Xie Y, Paul NC, Roopesh MS, Shah DH, Tang J. Water sorption characteristics of freeze-dried bacteria in low-moisture foods. Int J Food Microbiol 2021; 362:109494. [PMID: 34895752 DOI: 10.1016/j.ijfoodmicro.2021.109494] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 10/08/2021] [Accepted: 11/22/2021] [Indexed: 11/17/2022]
Abstract
Water sorption isotherms of bacteria reflect the water activity with the change of moisture content of bacteria at a specific temperature. The temperature-dependency of water activity change can help to understand the thermal resistance of bacteria during a thermal process. Thermal resistance of bacteria in low-moisture foods may differ significantly depending on the physiological characteristics of microorganisms, including cell structure, existence of biofilms, and growth state. Previous studies demonstrated that the incremental change of aw in bacterial cells during thermal treatments resulted in changes in their thermotolerance. In this study, a pathogen associated with low-moisture foods outbreaks, Salmonella Enteritidis PT30 (in planktonic and biofilm forms), and its validated surrogate, Enterococcus faecium, were lyophilized and their water sorption isotherms (WSI) at 20, 40, and 60 °C were determined by using a vapor sorption analyzer and simulated by the Guggenheim, Anderson and De Boer model (GAB). The published thermal death times at 80 °C (D80 °C-values) of these bacteria in low-moisture environments were related with their WSI-derived aw changes. The results showed that planktonic E. faecium and biofilms of Salmonella, exhibiting higher thermal resistance compared to the planktonic cultures of Salmonella, had a smaller increase in aw when thermally treated from 20 to 60 °C in sealed test cells. The computational modeling also showed that when temperature increased from 20 to 60 °C, with an increase in relative humidity from 10% to 60%, freeze-dried planktonic E. faecium and Salmonella cells would equilibrate to their surrounding environments in 0.15 s and 0.25 s, respectively, suggesting a rapid equilibration of bacterial cells to their microenvironment. However, control of bacteria with different cell structure and growth state would require further attentions on process design adjustment because of their different water sorption characteristics.
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Affiliation(s)
- Jie Xu
- Department of Biological Systems Engineering, Washington State University, P.O. Box 646120, Pullman, WA 99164-6120, USA; Center for Nanotechnology and Nanotoxicology, Harvard T.H. Chan School of Public Health, Harvard University, Boston, MA 02115, USA.
| | - Yucen Xie
- Department of Biological Systems Engineering, Washington State University, P.O. Box 646120, Pullman, WA 99164-6120, USA
| | - Narayan C Paul
- Texas A&M Veterinary Medical Diagnostic Laboratory, 483 Agronomy Rd, College Station, TCX 77843, USA
| | - M S Roopesh
- Department of Agricultural, Food and Nutritional Science, University of Alberta, 3-16 Agriculture/Forestry Centre, Edmonton, AB T6G 2P5, Canada
| | - Devendra H Shah
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, WA 99164-6120, USA
| | - Juming Tang
- Department of Biological Systems Engineering, Washington State University, P.O. Box 646120, Pullman, WA 99164-6120, USA
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Yang X, Ha G, Needleman D. A coarse-grained NADH redox model enables inference of subcellular metabolic fluxes from fluorescence lifetime imaging. eLife 2021; 10:73808. [PMID: 34806591 PMCID: PMC8935353 DOI: 10.7554/elife.73808] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Accepted: 11/19/2021] [Indexed: 11/13/2022] Open
Abstract
Mitochondrial metabolism is of central importance to diverse aspects of cell and developmental biology. Defects in mitochondria are associated with many diseases, including cancer, neuropathology, and infertility. Our understanding of mitochondrial metabolism in situ and dysfunction in diseases are limited by the lack of techniques to measure mitochondrial metabolic fluxes with sufficient spatiotemporal resolution. Herein, we developed a new method to infer mitochondrial metabolic fluxes in living cells with subcellular resolution from fluorescence lifetime imaging of NADH. This result is based on the use of a generic coarse-grained NADH redox model. We tested the model in mouse oocytes and human tissue culture cells subject to a wide variety of perturbations by comparing predicted fluxes through the electron transport chain (ETC) to direct measurements of oxygen consumption rate. Interpreting the fluorescence lifetime imaging microscopy measurements of NADH using this model, we discovered a homeostasis of ETC flux in mouse oocytes: perturbations of nutrient supply and energy demand of the cell do not change ETC flux despite significantly impacting NADH metabolic state. Furthermore, we observed a subcellular spatial gradient of ETC flux in mouse oocytes and found that this gradient is primarily a result of a spatially heterogeneous mitochondrial proton leak. We concluded from these observations that ETC flux in mouse oocytes is not controlled by energy demand or supply, but by the intrinsic rates of mitochondrial respiration.
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Affiliation(s)
- Xingbo Yang
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, United States
| | - Gloria Ha
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, United States
| | - Dan Needleman
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, United States
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42
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Krueger BC, Fowler GD, Templeton MR, Septien S. Faecal sludge pyrolysis: Understanding the relationships between organic composition and thermal decomposition. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 298:113456. [PMID: 34364246 DOI: 10.1016/j.jenvman.2021.113456] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 07/26/2021] [Accepted: 07/30/2021] [Indexed: 06/13/2023]
Abstract
Sludge treatment is an integral part of faecal sludge management in non-sewered sanitation settings. Development of pyrolysis as a suitable sludge treatment method requires thorough knowledge about the properties and thermal decomposition mechanisms of the feedstock. This study aimed to improve the current lack of understanding concerning relevant sludge properties and their influence on the thermal decomposition characteristics. Major organic compounds (hemicellulose, cellulose, lignin, protein, oil and grease, other carbohydrates) were quantified in 30 faecal sludge samples taken from different sanitation technologies, providing the most comprehensive organic faecal sludge data set to date. This information was used to predict the sludge properties crucial to pyrolysis (calorific value, fixed carbon, volatile matter, carbon, hydrogen). Samples were then subjected to thermogravimetric analysis to delineate the influence of organic composition on thermal decomposition. Septic tanks showed lower median fractions of lignin (9.4%dwb) but higher oil and grease (10.7%dwb), compared with ventilated improved pit latrines (17.4%dwb and 4.6%dwb respectively) and urine diverting dry toilets (17.9%dwb and 4.7%dwb respectively). High fixed carbon fractions in lignin (45.1%dwb) and protein (18.8%dwb) suggested their importance for char formation, while oil and grease fully volatilised. For the first time, this study provided mechanistic insights into faecal sludge pyrolysis as a function of temperature and feedstock composition. Classification into the following three phases was proposed: decomposition of hemicellulose, cellulose, other carbohydrates, proteins and, partially, lignin (200-380 °C), continued decomposition of lignin and thermal cracking of oil and grease (380-500 °C) and continued carbonisation (>500 °C). The findings will facilitate the development and optimisation of faecal sludge pyrolysis, emphasising the importance of considering the organic composition of the feedstock.
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Affiliation(s)
- Benedict C Krueger
- Department of Civil and Environmental Engineering, Imperial College London, SW7 2AZ, UK.
| | - Geoffrey D Fowler
- Department of Civil and Environmental Engineering, Imperial College London, SW7 2AZ, UK
| | - Michael R Templeton
- Department of Civil and Environmental Engineering, Imperial College London, SW7 2AZ, UK
| | - Santiago Septien
- Water, Sanitation & Hygiene Research & Development Centre, University of KwaZulu-Natal, Durban, 4041, South Africa
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43
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Gardner JG, Schreier HJ. Unifying themes and distinct features of carbon and nitrogen assimilation by polysaccharide-degrading bacteria: a summary of four model systems. Appl Microbiol Biotechnol 2021; 105:8109-8127. [PMID: 34611726 DOI: 10.1007/s00253-021-11614-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 09/20/2021] [Accepted: 09/21/2021] [Indexed: 11/24/2022]
Abstract
Our current understanding of enzymatic polysaccharide degradation has come from a huge number of in vitro studies with purified enzymes. While this vast body of work has been invaluable in identifying and characterizing novel mechanisms of action and engineering desirable traits into these enzymes, a comprehensive picture of how these enzymes work as part of a native in vivo system is less clear. Recently, several model bacteria have emerged with genetic systems that allow for a more nuanced study of carbohydrate active enzymes (CAZymes) and how their activity affects bacterial carbon metabolism. With these bacterial model systems, it is now possible to not only study a single nutrient system in isolation (i.e., carbohydrate degradation and carbon metabolism), but also how multiple systems are integrated. Given that most environmental polysaccharides are carbon rich but nitrogen poor (e.g., lignocellulose), the interplay between carbon and nitrogen metabolism in polysaccharide-degrading bacteria can now be studied in a physiologically relevant manner. Therefore, in this review, we have summarized what has been experimentally determined for CAZyme regulation, production, and export in relation to nitrogen metabolism for two Gram-positive (Caldicellulosiruptor bescii and Clostridium thermocellum) and two Gram-negative (Bacteroides thetaiotaomicron and Cellvibrio japonicus) polysaccharide-degrading bacteria. By comparing and contrasting these four bacteria, we have highlighted the shared and unique features of each, with a focus on in vivo studies, in regard to carbon and nitrogen assimilation. We conclude with what we believe are two important questions that can act as guideposts for future work to better understand the integration of carbon and nitrogen metabolism in polysaccharide-degrading bacteria. KEY POINTS: • Regardless of CAZyme deployment system, the generation of a local pool of oligosaccharides is a common strategy among Gram-negative and Gram-positive polysaccharide degraders as a means to maximally recoup the energy expenditure of CAZyme production and export. • Due to the nitrogen deficiency of insoluble polysaccharide-containing substrates, Gram-negative and Gram-positive polysaccharide degraders have a diverse set of strategies for supplementation and assimilation. • Future work needs to precisely characterize the energetic expenditures of CAZyme deployment and bolster our understanding of how carbon and nitrogen metabolism are integrated in both Gram-negative and Gram-positive polysaccharide-degrading bacteria, as both of these will significantly influence a given bacterium's suitability for biotechnology applications.
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Affiliation(s)
- Jeffrey G Gardner
- Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, MD, USA.
| | - Harold J Schreier
- Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, MD, USA.,Department of Marine Biotechnology, Institute of Marine and Environmental Technology, University of Maryland, Baltimore County, Baltimore, MD, USA
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Belliveau NM, Chure G, Hueschen CL, Garcia HG, Kondev J, Fisher DS, Theriot JA, Phillips R. Fundamental limits on the rate of bacterial growth and their influence on proteomic composition. Cell Syst 2021; 12:924-944.e2. [PMID: 34214468 PMCID: PMC8460600 DOI: 10.1016/j.cels.2021.06.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 04/12/2021] [Accepted: 06/04/2021] [Indexed: 12/11/2022]
Abstract
Despite abundant measurements of bacterial growth rate, cell size, and protein content, we lack a rigorous understanding of what sets the scale of these quantities and when protein abundances should (or should not) depend on growth rate. Here, we estimate the basic requirements and physical constraints on steady-state growth by considering key processes in cellular physiology across a collection of Escherichia coli proteomic data covering ≈4,000 proteins and 36 growth rates. Our analysis suggests that cells are predominantly tuned for the task of cell doubling across a continuum of growth rates; specific processes do not limit growth rate or dictate cell size. We present a model of proteomic regulation as a function of nutrient supply that reconciles observed interdependences between protein synthesis, cell size, and growth rate and propose that a theoretical inability to parallelize ribosomal synthesis places a firm limit on the achievable growth rate. A record of this paper's transparent peer review process is included in the supplemental information.
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Affiliation(s)
- Nathan M Belliveau
- Department of Biology, Howard Hughes Medical Institute, University of Washington, Seattle, WA 98105, USA
| | - Griffin Chure
- Department of Applied Physics, California Institute of Technology, Pasadena, CA 91125, USA
| | - Christina L Hueschen
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Hernan G Garcia
- Department of Molecular Cell Biology and Department of Physics, University of California Berkeley, Berkeley, CA 94720, USA
| | - Jane Kondev
- Department of Physics, Brandeis University, Waltham, MA 02453, USA
| | - Daniel S Fisher
- Department of Applied Physics, Stanford University, Stanford, CA 94305, USA
| | - Julie A Theriot
- Department of Biology, Howard Hughes Medical Institute, University of Washington, Seattle, WA 98105, USA.
| | - Rob Phillips
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA; Department of Physics, California Institute of Technology, Pasadena, CA 91125, USA.
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The soil microbial food web revisited: Predatory myxobacteria as keystone taxa? THE ISME JOURNAL 2021; 15:2665-2675. [PMID: 33746204 PMCID: PMC8397742 DOI: 10.1038/s41396-021-00958-2] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 02/24/2021] [Accepted: 03/04/2021] [Indexed: 02/07/2023]
Abstract
Trophic interactions are crucial for carbon cycling in food webs. Traditionally, eukaryotic micropredators are considered the major micropredators of bacteria in soils, although bacteria like myxobacteria and Bdellovibrio are also known bacterivores. Until recently, it was impossible to assess the abundance of prokaryotes and eukaryotes in soil food webs simultaneously. Using metatranscriptomic three-domain community profiling we identified pro- and eukaryotic micropredators in 11 European mineral and organic soils from different climes. Myxobacteria comprised 1.5-9.7% of all obtained SSU rRNA transcripts and more than 60% of all identified potential bacterivores in most soils. The name-giving and well-characterized predatory bacteria affiliated with the Myxococcaceae were barely present, while Haliangiaceae and Polyangiaceae dominated. In predation assays, representatives of the latter showed prey spectra as broad as the Myxococcaceae. 18S rRNA transcripts from eukaryotic micropredators, like amoeba and nematodes, were generally less abundant than myxobacterial 16S rRNA transcripts, especially in mineral soils. Although SSU rRNA does not directly reflect organismic abundance, our findings indicate that myxobacteria could be keystone taxa in the soil microbial food web, with potential impact on prokaryotic community composition. Further, they suggest an overlooked, yet ecologically relevant food web module, independent of eukaryotic micropredators and subject to separate environmental and evolutionary pressures.
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Wen Y, Wang J, Liu X, Li S, Hu J, Luo Y. Regulating glycolysis and heat shock proteins in Gannan yaks ( Bos grunniens) in response to hypoxia of the Qinghai-Tibet Plateau. Arch Anim Breed 2021; 64:345-353. [PMID: 34458561 PMCID: PMC8386194 DOI: 10.5194/aab-64-345-2021] [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: 05/08/2021] [Accepted: 07/21/2021] [Indexed: 11/11/2022] Open
Abstract
Glycolysis and heat shock proteins (HSPs) play an important role in
hypoxia-intolerant species during hypoxia conditions. This study was
conducted to evaluate the differences of glycolysis and heat shock proteins
(HSPs) in Gannan yaks (Bos grunniens), with the main goal of understanding how the response
to hypoxia changes with altitude. Here, the genes and enzymes of glycolysis
and HSPs were detected in heart, liver, lung, kidney, and longissimus dorsi
from Gannan yaks at different altitude (2500 and 3500 m) using qPCR,
western blot, and enzyme kits. The results showed that the expression of
HIF1A and PDK4 was increased with altitude (P<0.01) in above tissues.
Significantly increased lactate
dehydrogenase (LDH), adenosine triphosphate (ATP), and nicotinamide adenine
dinucleotide (NADH) levels and the ratio of
NADH/NAD+ were also observed in heart, lung, and longissimus dorsi tissues
(P<0.05), as well as a decreased citric acid (CA) level (P<0.05).
Furthermore, we observed significant global increases in the protein and
mRNA expression levels of both the ATP-independent HSP27 and the
ATP-dependent HSP60 during hypoxic conditions (P<0.01). These
findings revealed that hypoxia-reprogrammed glucose metabolism promotes
energy supply via up-regulated glycolysis and weakness of the tricarboxylic acid
(TCA) cycle. HSPs were activated and the prioritization of cytoprotective
protein chaperone functions over energy conservation in yak under hypoxic conditions.
These results are useful to better understand the unique adaptability of yak, allowing them to survive in hypoxia conditions.
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Affiliation(s)
- Yuliang Wen
- Faculty of Animal Science and Technology, Gansu Agricultural University, Gansu Key Laboratory of Herbivorous Animal Biotechnology, Lanzhou 730070, China
| | - Jiqing Wang
- Faculty of Animal Science and Technology, Gansu Agricultural University, Gansu Key Laboratory of Herbivorous Animal Biotechnology, Lanzhou 730070, China
| | - Xiu Liu
- Faculty of Animal Science and Technology, Gansu Agricultural University, Gansu Key Laboratory of Herbivorous Animal Biotechnology, Lanzhou 730070, China
| | - Shaobin Li
- Faculty of Animal Science and Technology, Gansu Agricultural University, Gansu Key Laboratory of Herbivorous Animal Biotechnology, Lanzhou 730070, China
| | - Jiang Hu
- Faculty of Animal Science and Technology, Gansu Agricultural University, Gansu Key Laboratory of Herbivorous Animal Biotechnology, Lanzhou 730070, China
| | - Yuzhu Luo
- Faculty of Animal Science and Technology, Gansu Agricultural University, Gansu Key Laboratory of Herbivorous Animal Biotechnology, Lanzhou 730070, China
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Groisman EA, Duprey A, Choi J. How the PhoP/PhoQ System Controls Virulence and Mg 2+ Homeostasis: Lessons in Signal Transduction, Pathogenesis, Physiology, and Evolution. Microbiol Mol Biol Rev 2021; 85:e0017620. [PMID: 34191587 PMCID: PMC8483708 DOI: 10.1128/mmbr.00176-20] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The PhoP/PhoQ two-component system governs virulence, Mg2+ homeostasis, and resistance to a variety of antimicrobial agents, including acidic pH and cationic antimicrobial peptides, in several Gram-negative bacterial species. Best understood in Salmonella enterica serovar Typhimurium, the PhoP/PhoQ system consists o-regulated gene products alter PhoP-P amounts, even under constant inducing conditions. PhoP-P controls the abundance of hundreds of proteins both directly, by having transcriptional effects on the corresponding genes, and indirectly, by modifying the abundance, activity, or stability of other transcription factors, regulatory RNAs, protease regulators, and metabolites. The investigation of PhoP/PhoQ has uncovered novel forms of signal transduction and the physiological consequences of regulon evolution.
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Affiliation(s)
- Eduardo A. Groisman
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA
- Yale Microbial Sciences Institute, West Haven, Connecticut, USA
| | - Alexandre Duprey
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA
| | - Jeongjoon Choi
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA
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48
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Effect of glycolysis and heat shock proteins on hypoxia adaptation of Tibetan sheep at different altitude. Gene 2021; 803:145893. [PMID: 34384864 DOI: 10.1016/j.gene.2021.145893] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 08/04/2021] [Accepted: 08/06/2021] [Indexed: 12/30/2022]
Abstract
Glycolysis and heat shock proteins (HSPs) play an important role in mediating the physiological response to hypoxia. The changes of glycolysis and HSPs with altitude would provide important information regarding ways to prevent hypoxia-related sickness in both animals and humans. In this study, the expression pattern of HIF1A, PDK4, HSP27 and HSP60, indexes activity and content of glucose metabolism were detected in heart, lung, brain, and quadriceps femoris taken from Tibetan sheep (Ovis aries) that were raised at different altitudes (2,500 m, 3,500 m and 4,500 m). The expression of HIF1A and PDK4 was increased with increasing altitude in all of the tissues. The lactate dehydrogenase (LDH) activities and adenosine triphosphate (ATP), nicotinamide adenine dinucleotide (NADH (redox state), NAD+), lactic acid (LA), pyruvic acid (PA) contents were all increased with increasing altitude in all of the tissues. The ratio of NADH/NAD+ and LA/PA were higher in sheep at an altitude of 4,500 m than of 3,500 m and 2,500 m in all tissues, except for the NADH/NAD+ ratio in lung and quadriceps femoris. An increase in the protein and mRNA expression of ATP-independent HSP27 during hypoxia condition was detected. The expression of ATP-dependent HSP60 mRNA and protein was increased in all of the tissues at an altitude of 3,500 m than of 2,500 m, but was decreased at an altitude of 4,500 m. These results suggest that glycolysis and HSPs are upregulated to ensure energy supply and proteostasis during hypoxia, but energy conservation may be prioritized over cytoprotective protein chaperoning in Tibetan sheep tissues during extreme hypoxia.
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Physical bioenergetics: Energy fluxes, budgets, and constraints in cells. Proc Natl Acad Sci U S A 2021; 118:2026786118. [PMID: 34140336 DOI: 10.1073/pnas.2026786118] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Cells are the basic units of all living matter which harness the flow of energy to drive the processes of life. While the biochemical networks involved in energy transduction are well-characterized, the energetic costs and constraints for specific cellular processes remain largely unknown. In particular, what are the energy budgets of cells? What are the constraints and limits energy flows impose on cellular processes? Do cells operate near these limits, and if so how do energetic constraints impact cellular functions? Physics has provided many tools to study nonequilibrium systems and to define physical limits, but applying these tools to cell biology remains a challenge. Physical bioenergetics, which resides at the interface of nonequilibrium physics, energy metabolism, and cell biology, seeks to understand how much energy cells are using, how they partition this energy between different cellular processes, and the associated energetic constraints. Here we review recent advances and discuss open questions and challenges in physical bioenergetics.
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Inclusion of maintenance energy improves the intracellular flux predictions of CHO. PLoS Comput Biol 2021; 17:e1009022. [PMID: 34115746 PMCID: PMC8221792 DOI: 10.1371/journal.pcbi.1009022] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 06/23/2021] [Accepted: 04/28/2021] [Indexed: 11/19/2022] Open
Abstract
Chinese hamster ovary (CHO) cells are the leading platform for the production of biopharmaceuticals with human-like glycosylation. The standard practice for cell line generation relies on trial and error approaches such as adaptive evolution and high-throughput screening, which typically take several months. Metabolic modeling could aid in designing better producer cell lines and thus shorten development times. The genome-scale metabolic model (GSMM) of CHO can accurately predict growth rates. However, in order to predict rational engineering strategies it also needs to accurately predict intracellular fluxes. In this work we evaluated the agreement between the fluxes predicted by parsimonious flux balance analysis (pFBA) using the CHO GSMM and a wide range of 13C metabolic flux data from literature. While glycolytic fluxes were predicted relatively well, the fluxes of tricarboxylic acid (TCA) cycle were vastly underestimated due to too low energy demand. Inclusion of computationally estimated maintenance energy significantly improved the overall accuracy of intracellular flux predictions. Maintenance energy was therefore determined experimentally by running continuous cultures at different growth rates and evaluating their respective energy consumption. The experimentally and computationally determined maintenance energy were in good agreement. Additionally, we compared alternative objective functions (minimization of uptake rates of seven nonessential metabolites) to the biomass objective. While the predictions of the uptake rates were quite inaccurate for most objectives, the predictions of the intracellular fluxes were comparable to the biomass objective function. There is an increasing demand for protein pharmaceuticals, especially monoclonal antibodies. Chinese Hamster Ovary (CHO) are currently the leading production host due to their ability to perform human-like post-translational modifications. However, it typically takes several months of trial-and-error approaches to develop a high-producer cell line. Metabolic modelling has the potential to make cell line and process development faster and cheaper by predicting targeted modifications to the cell line genome, cultivation medium or bioprocess. In fact, genome-scale metabolic reconstructions of CHO are already available, and ready for use in cell line development. However, in order to successfully use these models, we need to make sure that they are able to accurately predict metabolic phenotypes. Here we use genome-scale metabolic models of CHO to evaluate the models’ ability to correctly predict intracellular flux distributions. We find that a crucial key ingredient for the correct estimation of central carbon fluxes is the non-growth associated maintenance energy (mATP). We estimated mATP computationally and confirmed it experimentally. Adding this single constraint leads to significantly better predictions of intracellular fluxes, especially in glycolysis and the tricarboxylic acid cycle.
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