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Campbell IH, Campbell H. The metabolic overdrive hypothesis: hyperglycolysis and glutaminolysis in bipolar mania. Mol Psychiatry 2024; 29:1521-1527. [PMID: 38273108 PMCID: PMC11189810 DOI: 10.1038/s41380-024-02431-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 12/12/2023] [Accepted: 01/11/2024] [Indexed: 01/27/2024]
Abstract
Evidence from diverse areas of research including chronobiology, metabolomics and magnetic resonance spectroscopy indicate that energy dysregulation is a central feature of bipolar disorder pathophysiology. In this paper, we propose that mania represents a condition of heightened cerebral energy metabolism facilitated by hyperglycolysis and glutaminolysis. When oxidative glucose metabolism becomes impaired in the brain, neurons can utilize glutamate as an alternative substrate to generate energy through oxidative phosphorylation. Glycolysis in astrocytes fuels the formation of denovo glutamate, which can be used as a mitochondrial fuel source in neurons via transamination to alpha-ketoglutarate and subsequent reductive carboxylation to replenish tricarboxylic acid cycle intermediates. Upregulation of glycolysis and glutaminolysis in this manner causes the brain to enter a state of heightened metabolism and excitatory activity which we propose to underlie the subjective experience of mania. Under normal conditions, this mechanism serves an adaptive function to transiently upregulate brain metabolism in response to acute energy demand. However, when recruited in the long term to counteract impaired oxidative metabolism it may become a pathological process. In this article, we develop these ideas in detail, present supporting evidence and propose this as a novel avenue of investigation to understand the biological basis for mania.
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Affiliation(s)
- Iain H Campbell
- Division of Psychiatry, Centre for Clinical Brain Sciences, University of Edinburgh, Kennedy Tower, Royal Edinburgh Hospital, Edinburgh, EH10 5HF, UK.
| | - Harry Campbell
- Usher Institute, Centre for Global Health Research, University of Edinburgh, Craigour House, 450 Old Dalkeith Rd, Edinburgh, EH16 4SS, UK
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Fonseca GG. Metabolic engineering of Kluyveromyces marxianus for biomass-based applications. 3 Biotech 2022; 12:259. [PMID: 36068842 PMCID: PMC9440961 DOI: 10.1007/s13205-022-03324-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 08/22/2022] [Indexed: 11/01/2022] Open
Abstract
Kluyveromyces marxianus ATCC 26,548 was cultivated in aerobic chemostats with [1-13C] and [U-13C] glucose as carbon source under three different growth conditions (0.10, 0.25, and 0.5 h-1) to evaluate metabolic fluxes. Carbon balances closed always within 97-102%. Growth was carbon limited, and the cell yield on glucose was the same. The extracellular side-product formation was very low, totaling 0.0008 C-mol C-mol-1 substrate at 0.5 h-1. The intracellular flux ratios did not show significant variation for metabolic flux analysis from labelling and biomass composition and metabolic flux ratio analysis from labelling. The observed strictly oxidative metabolism and the stability of the metabolism in terms of fluxes even at high growth rates, without triggering out the synthesis of by-products, is an extremely desired condition that underlines the potential of K. marxianus for biotechnological biomass-related applications and the comprehension of the metabolic pools and pathways is an important step to engineering this organism. Supplementary Information The online version contains supplementary material available at 10.1007/s13205-022-03324-x.
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Affiliation(s)
- Gustavo Graciano Fonseca
- Faculty of Natural Resource Sciences, School of Business and Science, University of Akureyri, Borgir v. Nordurslod, 600 Akureyri, Iceland
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Zhang H, Li S, Ma B, Huang T, Qiu H, Zhao Z, Huang X, Liu K. Nitrate removal characteristics and 13C metabolic pathways of aerobic denitrifying bacterium Paracoccus denitrificans Z195. BIORESOURCE TECHNOLOGY 2020; 307:123230. [PMID: 32222687 DOI: 10.1016/j.biortech.2020.123230] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 03/17/2020] [Accepted: 03/19/2020] [Indexed: 06/10/2023]
Abstract
Strain Z195 was isolated and identified as Paracoccus denitrificans. Z195 exhibited efficient aerobic denitrification and carbon removal abilities, and removed 93.74% of total nitrogen (TN) and 97.81% of total organic carbon.71.88% of nitrogen was lost as gaseous products.13C-metabolic flux analysis revealed that 95% and 132% of the carbon fluxes entered the Entner-Doudoroff (ED) pathway and tricarboxylic acid (TCA) cycle, respectively. Electrons produced by carbon metabolism markedly promoted the processes of nitrogen metabolism process and aerobic respiration. A response surface methodology model demonstrated that the optimal conditions for the maximum TN removal were a C/N ratio of 7.47, shaking speed of 108 rpm, temperature of 31 °C and initial pH of 8.02. Additionally, the average TN and chemical oxygen demand removal efficiencies of raw wastewater were 89% and 91%, respectively. The results give new insight for understanding metabolic flux analysis of aerobic denitrifying bacteria.
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Affiliation(s)
- Haihan Zhang
- Shaanxi Key Laboratory of Environmental Engineering, Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China.
| | - Sulin Li
- Shaanxi Key Laboratory of Environmental Engineering, Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Ben Ma
- Shaanxi Key Laboratory of Environmental Engineering, Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Tinglin Huang
- Shaanxi Key Laboratory of Environmental Engineering, Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Hui Qiu
- Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Zhenfang Zhao
- Shaanxi Key Laboratory of Environmental Engineering, Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Xin Huang
- Shaanxi Key Laboratory of Environmental Engineering, Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Kaiwen Liu
- Shaanxi Key Laboratory of Environmental Engineering, Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China
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Worland AM, Czajka JJ, Li Y, Wang Y, Tang YJ, Su WW. Biosynthesis of terpene compounds using the non-model yeast Yarrowia lipolytica: grand challenges and a few perspectives. Curr Opin Biotechnol 2020; 64:134-140. [PMID: 32299032 DOI: 10.1016/j.copbio.2020.02.020] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 01/24/2020] [Accepted: 02/25/2020] [Indexed: 12/17/2022]
Abstract
Yarrowia lipolytica has emerged as an important non-model host for terpene production. However, three main challenges remain in industrial production using this yeast. First, considerable knowledge gaps exist in metabolic flux across multiple compartments, cofactor generation, and catabolism of non-sugar carbon sources. Second, many enzymatic steps in the complex-terpene synthesis pathway can pose rate-limitations, causing accumulation of toxic intermediates and increased metabolic burdens. Third, metabolic shifts, morphological changes, and genetic mutations are poorly characterized under industrial fermentation conditions. To overcome these challenges, systems metabolic analysis, protein engineering, novel pathway engineering, model-guided strain design, and fermentation optimization have been attempted with some successes. Further developments that address these challenges are needed to advance the Yarrowia lipolytica platform for industrial-scale production of high-value terpenes, including those with highly complex structures such as anticancer molecules withanolides and insecticidal limonoids.
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Affiliation(s)
- Alyssa M Worland
- Department of Energy, Environmental and Chemical Engineering, Washington University, St. Louis, MO 63130, United States
| | - Jeffrey J Czajka
- Department of Energy, Environmental and Chemical Engineering, Washington University, St. Louis, MO 63130, United States
| | - Yanran Li
- Department of Chemical and Environmental Engineering, University of California, Riverside, CA 92521, United States
| | - Yechun Wang
- Arch Innotek, LLC, 4320 Forest Park Ave, St. Louis, MO 63108, United States
| | - Yinjie J Tang
- Department of Energy, Environmental and Chemical Engineering, Washington University, St. Louis, MO 63130, United States
| | - Wei Wen Su
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, HI 96822, United States.
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