Enhanced 1,3-propanediol production in Klebsiella pneumoniae
 by a combined strategy of strengthening the TCA cycle and weakening the glucose effect

ABSTRACT 1,3-Propanediol (1,3-PDO) is an important synthetic monomer for the production of polytrimethylene terephthalate (PTT). Here, we engineered Klebsiella pneumoniae by a multi-strategy to improve 1,3-PDO production and reduce by-products synthesis. First, the 2,3-butanediol (2,3-BDO) synthesis pathway was blocked by deleting the budB gene, resulting in a 74% decrease of 2,3-BDO titer. The synthesis of lactate was decreased by 79% via deleting the ldhA gene, leading to a 10% increase of 1,3-PDO titer. Further, reducing ethanol synthesis by deleting the aldA gene led to a 64% decrease of ethanol titer, and the 1,3-PDO titer and yield on glycerol increased by 12 and 10%, respectively. Strengthening the TCA cycle by overexpressing the mdh gene improved 1,3-PDO synthesis effectively. Under 5-L fed-batch fermentation conditions, compared to wild type strain, the production of 2,3-BDO, lactate and ethanol in the mutant strain decreased by 73, 65 and 50%, respectively. Finally, the production of 1,3-PDO was 73.5 g/L with a molar yield of 0.67 mol/mol glycerol, improved 16% and 20%, respectively. This work provides a combined strategy for improving 1,3-PDO production by strengthening the TCA cycle to relieve metabolic stress by deleting genes of by-products synthesis, which was also beneficial for the extraction and separation of downstream products.

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A systematic analysis of hypermucoviscosity and capsule reveals distinct and overlapping genes that impact Klebsiella pneumoniae fitness

10.1101/2020.06.22.164582 ◽

2020 ◽

Cited By ~ 1

Author(s):

Laura A. Mike ◽

Andrew J. Stark ◽

Valerie S. Forsyth ◽

Jay Vornhagen ◽

Sara N. Smith ◽

...

Keyword(s):

Klebsiella Pneumoniae ◽

Capsular Polysaccharide ◽

Tca Cycle ◽

Central Metabolism ◽

Healthy Individuals ◽

Systematic Analysis ◽

Optimal Balance ◽

The Tca Cycle ◽

Cellular Factors

AbstractHypervirulent K. pneumoniae (hvKp) is a distinct pathotype that causes invasive community-acquired infections in healthy individuals. Hypermucoviscosity (hmv) is a major phenotype associated with hvKp characterized by copious capsule production and poor sedimentation. Dissecting the individual functions of CPS production and hmv in hvKp has been stymied by the conflation of these two properties. Although hmv requires capsular polysaccharide (CPS) biosynthesis, other cellular factors may also be required and some fitness phenotypes ascribed to CPS may be distinctly attributed to hmv. To address this challenge, we systematically identified genes that impact capsule and hmv. We generated a condensed, ordered transposon library in hypervirulent strain KPPR1, then evaluated the CPS production and hmv phenotypes of the 3,733 transposon mutants, representing 72% of all open reading frames in the genome. We employed forward and reverse genetic screens to evaluate effects of novel and known genes on CPS biosynthesis and hmv. These screens expand our understanding of core genes that coordinate CPS biosynthesis and hmv, as well as identify central metabolism genes that distinctly impact CPS biosynthesis or hmv, specifically those related to purine metabolism, pyruvate metabolism and the TCA cycle. Six representative mutants, with varying levels of CPS production and hmv, were all significantly out-competed by wildtype in a murine model of disseminating pneumonia. This suggests that an optimal balance between cellular energetics, CPS biosynthesis and hmv are required for maximal fitness. Altogether, these data demonstrate that hmv requires both CPS biosynthesis and other cellular factors, and that these processes are integrated into the metabolic status of the cell. Therefore, hvKp may require certain nutrients to fully elaborate its virulence-associated properties to specifically cause deep tissue infections.Author summaryKlebsiella pneumoniae is a common multi-drug resistant hospital-associated pathogen, however some isolates are capable of causing community-acquired infections in otherwise healthy individuals. The strains causing community-acquired infections have some distinguishing characteristics, which include overproduction of capsule and hypermucoviscosity. Hypermucoviscous strains are very tacky and sediment poorly when centrifuged. Historically, hypermucoviscosity has been attributed to overproduction of capsular polysaccharide, but recent data suggest that other factors contribute to this bacterial phenotype. Moreover, it seems that capsule and hypermucoviscosity may have distinct roles in pathogenesis. In this study, we sought to systematically investigate the genes that contribute to capsule and hypermucoviscosity. We found that in most cases, genes coordinately impact both capsule biosynthesis and hypermucoviscosity. Some metabolic genes linked to the TCA cycle, however, only affect one of these properties. Here, we identify that capsule biosynthesis and hypermucoviscosity are tightly tied to central metabolism and that an optimal balance between metabolism, capsule, and hypermucoviscosity are important for in vivo fitness of K. pneumoniae. These results identify genes that can be further probed to dissect how capsule and hypermucoviscosity are coordinated in response to niche-specific nutrients. Such studies will expand our understanding of the factors that drive the pathobiology of hypervirulent K. pneumoniae.

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Liquid-liquid extraction of succinate using a dicopper cryptate

10.26434/chemrxiv.11786784 ◽

2020 ◽

Author(s):

Riccardo Mobili ◽

Sonia La Cognata ◽

Francesca Merlo ◽

Andrea Speltini ◽

Massimo Boiocchi ◽

...

Keyword(s):

Aqueous Phase ◽

Visible Spectrum ◽

Tca Cycle ◽

Residual Concentration ◽

Waste Products ◽

Liquid Liquid Extraction ◽

The Tca Cycle ◽

Quantitative Extraction ◽

Uv Visible

<div> <p>The extraction of the succinate dianion from a neutral aqueous solution into dichloromethane is obtained using a lipophilic cage-like dicopper(II) complex as the extractant. The quantitative extraction exploits the high affinity of the succinate anion for the cavity of the azacryptate. The anion is effectively transferred from the aqueous phase, buffered at pH 7 with HEPES, into dichloromethane. A 1:1 extractant:anion adduct is obtained. Extraction can be easily monitored by following changes in the UV-visible spectrum of the dicopper complex in dichloromethane, and by measuring the residual concentration of succinate in the aqueous phase by HPLC−UV. Considering i) the relevance of polycarboxylates in biochemistry, as e.g. normal intermediates of the TCA cycle, ii) the relevance of dicarboxylates in the environmental field, as e.g. waste products of industrial processes, and iii) the recently discovered role of succinate and other dicarboxylates in pathophysiological processes including cancer, our results open new perspectives for research in all contexts where selective recognition, trapping and extraction of polycarboxylates is required. </p> </div>

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Resolving the TCA cycle and pentose-phosphate pathway of Clostridium acetobutylicum ATCC 824: Isotopomer analysis, in vitro activities and expression analysis

Biotechnology Journal ◽

10.1002/biot.201000282 ◽

2010 ◽

Vol 6 (3) ◽

pp. 300-305 ◽

Cited By ~ 69

Author(s):

Scott B. Crown ◽

Dinesh C. Indurthi ◽

Woo Suk Ahn ◽

Jungik Choi ◽

Eleftherios T. Papoutsakis ◽

...

Keyword(s):

Expression Analysis ◽

Pentose Phosphate Pathway ◽

Clostridium Acetobutylicum ◽

Tca Cycle ◽

Pentose Phosphate ◽

The Tca Cycle ◽

Isotopomer Analysis ◽

Clostridium Acetobutylicum Atcc 824

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Mitochondrial Mistranslation in Brain Provokes a Metabolic Response Which Mitigates the Age-Associated Decline in Mitochondrial Gene Expression

International Journal of Molecular Sciences ◽

10.3390/ijms22052746 ◽

2021 ◽

Vol 22 (5) ◽

pp. 2746

Author(s):

Dimitri Shcherbakov ◽

Reda Juskeviciene ◽

Adrián Cortés Sanchón ◽

Margarita Brilkova ◽

Hubert Rehrauer ◽

...

Keyword(s):

Gene Expression ◽

Metabolic Response ◽

Mitochondrial Gene ◽

Tca Cycle ◽

Brain Mitochondria ◽

Mitochondrial Gene Expression ◽

Rna Seq ◽

The Tca Cycle ◽

Neurological Phenotype

Mitochondrial misreading, conferred by mutation V338Y in mitoribosomal protein Mrps5, in-vivo is associated with a subtle neurological phenotype. Brain mitochondria of homozygous knock-in mutant Mrps5V338Y/V338Y mice show decreased oxygen consumption and reduced ATP levels. Using a combination of unbiased RNA-Seq with untargeted metabolomics, we here demonstrate a concerted response, which alleviates the impaired functionality of OXPHOS complexes in Mrps5 mutant mice. This concerted response mitigates the age-associated decline in mitochondrial gene expression and compensates for impaired respiration by transcriptional upregulation of OXPHOS components together with anaplerotic replenishment of the TCA cycle (pyruvate, 2-ketoglutarate).

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Metabolomics of aging in primary fibroblasts from small and large breed dogs

GeroScience ◽

10.1007/s11357-021-00388-0 ◽

2021 ◽

Author(s):

Paul S. Brookes ◽

Ana Gabriela Jimenez

Keyword(s):

Aging Process ◽

Tca Cycle ◽

Therapeutic Strategies ◽

Targeted Metabolomics ◽

The Tca Cycle ◽

Age Dependent ◽

Primary Fibroblasts ◽

Aging Rates ◽

Underlying Mechanisms ◽

Coenzyme A Biosynthesis

AbstractAmong several animal groups (eutherian mammals, birds, reptiles), lifespan positively correlates with body mass over several orders of magnitude. Contradicting this pattern are domesticated dogs, with small dog breeds exhibiting significantly longer lifespans than large dog breeds. The underlying mechanisms of differing aging rates across body masses are unclear, but it is generally agreed that metabolism is a significant regulator of the aging process. Herein, we performed a targeted metabolomics analysis on primary fibroblasts isolated from small and large breed young and old dogs. Regardless of size, older dogs exhibited lower glutathione and ATP, consistent with a role for oxidative stress and bioenergetic decline in aging. Furthermore, several size-specific metabolic patterns were observed with aging, including the following: (i) An apparent defect in the lower half of glycolysis in large old dogs at the level of pyruvate kinase. (ii) Increased glutamine anaplerosis into the TCA cycle in large old dogs. (iii) A potential defect in coenzyme A biosynthesis in large old dogs. (iv) Low nucleotide levels in small young dogs that corrected with age. (v) An age-dependent increase in carnitine in small dogs that was absent in large dogs. Overall, these data support the hypothesis that alterations in metabolism may underlie the different lifespans of small vs. large breed dogs, and further work in this area may afford potential therapeutic strategies to improve the lifespan of large dogs.

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The Metabolic Fates of Pyruvate in Normal and Neoplastic Cells

Cells ◽

10.3390/cells10040762 ◽

2021 ◽

Vol 10 (4) ◽

pp. 762

Author(s):

Edward V. Prochownik ◽

Huabo Wang

Keyword(s):

Metabolic Pathways ◽

Redox State ◽

Pyruvate Dehydrogenase Complex ◽

Tca Cycle ◽

Vascular Supply ◽

Extrinsic Factors ◽

The Tca Cycle ◽

Initial Substrate ◽

Numerous Cell ◽

Bio Synthesis

Pyruvate occupies a central metabolic node by virtue of its position at the crossroads of glycolysis and the tricarboxylic acid (TCA) cycle and its production and fate being governed by numerous cell-intrinsic and extrinsic factors. The former includes the cell’s type, redox state, ATP content, metabolic requirements and the activities of other metabolic pathways. The latter include the extracellular oxygen concentration, pH and nutrient levels, which are in turn governed by the vascular supply. Within this context, we discuss the six pathways that influence pyruvate content and utilization: 1. The lactate dehydrogenase pathway that either converts excess pyruvate to lactate or that regenerates pyruvate from lactate for use as a fuel or biosynthetic substrate; 2. The alanine pathway that generates alanine and other amino acids; 3. The pyruvate dehydrogenase complex pathway that provides acetyl-CoA, the TCA cycle’s initial substrate; 4. The pyruvate carboxylase reaction that anaplerotically supplies oxaloacetate; 5. The malic enzyme pathway that also links glycolysis and the TCA cycle and generates NADPH to support lipid bio-synthesis; and 6. The acetate bio-synthetic pathway that converts pyruvate directly to acetate. The review discusses the mechanisms controlling these pathways, how they cross-talk and how they cooperate and are regulated to maximize growth and achieve metabolic and energetic harmony.

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Phosphatases are involved in modulating the TCA cycle in plants

Molecular Plant ◽

10.1016/j.molp.2021.05.019 ◽

2021 ◽

Author(s):

Thomas D. Niehaus

Keyword(s):

Tca Cycle ◽

The Tca Cycle

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Comprehensive Plasma Metabolomic Profile of Patients with Advanced Neuroendocrine Tumors (NETs). Diagnostic and Biological Relevance

Cancers ◽

10.3390/cancers13112634 ◽

2021 ◽

Vol 13 (11) ◽

pp. 2634

Author(s):

Beatriz Soldevilla ◽

Angeles López-López ◽

Alberto Lens-Pardo ◽

Carlos Carretero-Puche ◽

Angeles Lopez-Gonzalvez ◽

...

Keyword(s):

Metabolic Pathways ◽

Metabolic Networks ◽

Tca Cycle ◽

Metabolomic Profile ◽

Diagnostic Potential ◽

The Tca Cycle ◽

Novel Biomarkers ◽

Potential Methods ◽

Clinical Potential ◽

First Time

Purpose: High-throughput “-omic” technologies have enabled the detailed analysis of metabolic networks in several cancers, but NETs have not been explored to date. We aim to assess the metabolomic profile of NET patients to understand metabolic deregulation in these tumors and identify novel biomarkers with clinical potential. Methods: Plasma samples from 77 NETs and 68 controls were profiled by GC−MS, CE−MS and LC−MS untargeted metabolomics. OPLS-DA was performed to evaluate metabolomic differences. Related pathways were explored using Metaboanalyst 4.0. Finally, ROC and OPLS-DA analyses were performed to select metabolites with biomarker potential. Results: We identified 155 differential compounds between NETs and controls. We have detected an increase of bile acids, sugars, oxidized lipids and oxidized products from arachidonic acid and a decrease of carnitine levels in NETs. MPA/MSEA identified 32 enriched metabolic pathways in NETs related with the TCA cycle and amino acid metabolism. Finally, OPLS-DA and ROC analysis revealed 48 metabolites with diagnostic potential. Conclusions: This study provides, for the first time, a comprehensive metabolic profile of NET patients and identifies a distinctive metabolic signature in plasma of potential clinical use. A reduced set of metabolites of high diagnostic accuracy has been identified. Additionally, new enriched metabolic pathways annotated may open innovative avenues of clinical research.

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Effects of corn steep liquor on β-poly(l-malic acid) production in Aureobasidium melanogenum

AMB Express ◽

10.1186/s13568-020-01147-8 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Genan Wang ◽

Bingyi Shi ◽

Pan Zhang ◽

Tingbin Zhao ◽

Haisong Yin ◽

...

Keyword(s):

Malic Acid ◽

Low Cost ◽

Corn Steep Liquor ◽

Enrichment Analysis ◽

Tca Cycle ◽

Water Soluble ◽

Growth And Yield ◽

The Tca Cycle ◽

Steep Liquor ◽

Aureobasidium Melanogenum

Abstractβ-poly(l-malic acid) (PMLA) is a water-soluble biopolymer used in medicine, food, and other industries. However, the low level of PMLA biosynthesis in microorganisms limits its further application in the biotechnological industry. In this study, corn steep liquor (CSL), which processes high nutritional value and low-cost characteristics, was selected as a growth factor to increase the PMLA production in strain, Aureobasidium melanogenum, and its metabolomics change under the CSL addition was investigated. The results indicated that, with 3 g/L CSL, PMLA production, cell growth, and yield (Yp/x) were increased by 32.76%, 41.82%, and 47.43%, respectively. The intracellular metabolites of A. melanogenum, such as amino acids, organic acids, and key intermediates in the TCA cycle, increased after the addition of CSL, and the enrichment analysis showed that tyrosine may play a major role in the PMLA biosynthesis. The results presented in this study demonstrated that the addition of CSL would be an efficient approach to improve PMLA production.

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