Pathway-specific tuning mechanisms in the metabolism of lignin and plastic aromatic carbons in Comamonas testosteroni
Ontology highlight
ABSTRACT:
ORGANISM(S): Comamonas testosteroni
PROVIDER: GSE192852 | GEO | 2022/11/17
REPOSITORIES: GEO
Similar Datasets
Project description:Widely reported discrepancies between metabolic flux and transcripts or enzyme levels in bacterial metabolism imply complex regulation mechanisms need to be considered, especially in new bacterial platforms for bioremediation and bioproduction. Comamonas testosteroni strains, which metabolize various natural and xenobiotic aromatic compounds, represent such platforms whose metabolic regulations are still unknown. Here, we identify analogous multi-level regulation mechanisms in the metabolism of two lignin-related (4-hydroxybenzoate and vanillate) and one plastic-related (terephthalate) aromatic compounds in C. testosteroni KF-1, a wastewater isolate. Transcription-level regulation controlled initial catabolism and cleavage of the compounds, but subsequent carbon fluxes in central carbon metabolism are governed by metabolite-level thermodynamic regulation. Quantitative 13C-fingerprinting of tricarboxylic acid cycle and cataplerotic reactions elucidate key carbon routing that is not evident from enzyme abundance changes. Therefore, as-needed transcriptional activation of aromatic catabolism is coupled with metabolic fine-tuning of central metabolism, thus delineating pathway candidates for different metabolic manipulations.
2022-11-21 | MTBLS3947 | MetaboLights
Project description:The degradation of aromatic compounds comprises an important step in the removal of pollutants and re-utilization of plastics and other non-biological polymers. Here we set out to study Pseudomonas sp. strain phDV1, a gram-negative bacterium that was selected for its ability to degrade aromatic compounds. In order to understand how the aromatic compounds and their degradation products are reintroduced in the metabolism of the bacteria and the systematic/metabolic response of the bacterium to the new carbon source, the proteome of this strain was analysed in the presence of succinate, phenol and o-, m-, p-cresol as sole carbon source. We then applied label-free quantitative proteomics to monitor overall proteome remodeling during metabolic adaptation to different carbon sources. As a reference proteome, we grew the bacteria in succinate and then compared the respective proteomes of bacteria grown on phenol and different cresols. In total, we identified 2295 proteins; 1908 proteins were used for quantification between different growth conditions. We found that 70, 100, 150 and 155 proteins were significantly differentially expressed in cells were grown in phenol, o-, m- and p-cresol-containing medium, respectively. The carbon source affected the synthesis of enzymes related to aromatic compound degradation, and in particular, the enzyme involved in the meta-pathway of monocyclic aromatic compounds degradation. In addition, proteins involved in the production of polyhydroxyalkanoate (PHA), an attractive biomaterial, showed higher expression levels in the presence of monocyclic aromatic compounds.Our results provide for the first time comprehensive information on the proteome response of this strain to monocyclic aromatic compounds.
2020-10-22 | PXD021237 | Pride
Project description:Lignin is an abundant aromatic polymer formed in plants by coupling reactions of p-coumaryl, coniferyl, and sinapyl alcohols. Pseudomonas putida KT2440 (P. putida KT2440), a robust soil bacterium, naturally catabolizes many aromatic compounds derived from lignin as carbon and energy sources and has been extensively engineered to valorize guaiacyl (G) and p-hydroxyphenyl (H) lignin-derived aromatic species to valuable chemicals. However, only a few studies report the capacity of Pseudomonads to grow on syringyl (S) lignin-derived compounds. In this work, we demonstrate that P. putida KT2440 catabolizes syringate in the presence of an auxiliary energy source. Overexpression of vanAB, encoding a native Rieske non-heme iron monooxygenase, enabled catabolism of syringate and syringaldehyde without an additional carbon and energy source. In vitro biochemical characterization of VanAB confirmed that this enzyme O-demethylates syringate to 3-O-methylgallate and, subsequently, 3-O-methylgallate to gallate, albeit 4- and 55-fold less efficiently than vanillate, respectively. Transcriptomics and proteomics experiments demonstrate that the galADBC transcripts and enzymes required for gallate catabolism are induced when vanAB is overexpressed during cultivation in syringate. Further, we show that that the endogenous protocatechuate-3,4-dioxygenase PcaHG ring-opens gallate to produce 2-pyrone-4,6-dicarboxylic acid (PDC), a promising bio-based chemical. Constitutive overexpression of vanAB and pcaHG along with galA deletion enabled PDC production from SA at a 70% (mol/mol) yield. Furthermore, leveraging the LigAB dioxygenase from Sphingobium sp. SYK-6 and VanAB O-demethylase from Pseudomonas sp. HR199 enabled simultaneous conversion of monomers with S-, G-, and H-type functionality to PDC at 82% (mol/mol) yield. Overall, this study elucidates a native pathway for catabolism of syringyl lignin-derived compounds in P. putida KT2440 and demonstrates the potential of this robust host for biological funneling of substrates derived from all three canonical monolignols.
2020-08-13 | MSV000085948 | MassIVE
Project description:Aromatic compounds are an important renewable source of commodity chemicals traditionally produced from fossil fuels. Aromatics derived from plant lignin can potentially be converted into commodity chemicals through depolymerization followed by microbial funneling of monomers and low molecular weight oligomers. This study investigates the catabolism of the b-5 linked aromatic dimer dehydrodiconiferyl alcohol (DC-A) by the bacterium Novosphingobium aromaticivorans. We used genome wide screens to identify candidate genes involved in DC-A catabolism. Subsequent in vivo and in vitro analyses of these candidates elucidated a catabolic pathway composed of four required gene products and several partially redundant dehydrogenases that convert DC-A to aromatic monomers that can be funneled into the central aromatic metabolic pathway of N. aromaticivorans. Specifically, a newly identified γ-formaldehyde lyase, PcfL, opens the phenylcoumaran ring to form a stilbene and formaldehyde. A lignostilbene dioxygenase, LsdD, then cleaves the stilbene to generate the aromatic monomers, vanillin and 5-formylferulate (5-FF). We also show that an aldehyde dehydrogenase FerD oxidizes 5-FF before it is decarboxylated by LigW, yielding ferulic acid. We found that some enzymes involved in b-5 catabolism pathway can act on multiple substrates and that some steps in the pathway can be mediated by multiple enzymes, providing new insights into the robust flexibility of aromatic catabolism in N. aromaticivorans. We performed a comparative genomic analysis to predict that key enzymes in the newly discovered b-5 aromatic catabolic pathway are common among Sphingomonads.
2024-02-29 | GSE259365 | GEO
Project description:Pyruvate dehydrogenase (PDH) catalyses the irreversible decarboxylation of pyruvate to acetyl-CoA, which feeds the tricarboxylic acids cycle. We analysed how the lack of PDH affects Pseudomonas putida metabolism. Inactivating PDH generated a strain that can no longer use compounds whose assimilation converges into pyruvate, including sugars and several amino acids. Compounds generating acetyl-CoA supported growth. Interestingly, inactivation of PDH led to loss of the carbon catabolite repression (CCR) effect that inhibits the assimilation of non-preferred compounds when other preferred ones are also present. P. putida can degrade many aromatic compounds, most of which generate acetyl-CoA, and is a useful bacterium for biotransformation and bioremediation processes. However, the genes involved in these metabolic pathways are frequently inhibited by CCR when substrates such as glucose or mixtures of amino acids are also present. Our results show that the PDH-null strain could efficiently degrade aromatic compounds in the presence of other preferred substrates, a condition in which the wild type strain could not mineralise them. Since lack of PDH limits the assimilation of many sugars and amino acids, and relieved CCR, the PDH-null strain could be useful in biotransformation or bioremediation processes that imply growth with mixtures of preferred substrates and aromatic compounds.
2024-07-03 | GSE263208 | GEO
Project description:To determine the wood degradation mechanism and its key genes of Lenzites gibbosa, we sequenced 15 transcriptomes of mycelial samples under woody environments at 3, 5, 7, and 11 d (D3, D5, D7, and D11) and non-woody environments (CK). All the transcripts were annotated as much as possible in eight databases to determine their function. The key genes and biological processes, relating to wood degradation, were predicted and screened. A total of 2069 differentially expressed genes (DEGs) were obtained in ten differential groups. Comparing wood with non-wood treatment conditions, the key genes were those participating in oxidation-reduction process, they were oxidoreductases and peroxidases genes, and their regulators genes; these genes mainly focused on the three biological processes of carbohydrate metabolism, lignin catabolism, and secondary metabolites biosynthesis, transport and catabolism. The mostly enriched subcategories in molecular function were oxidoreductase activity, peroxidase activity, and heme binding in GO annotation. One cellulose and hemicellulose degradation pathway and seven pathways related to lignin-derived aromatic compounds degradation or late lignin degradation were found. In conclusion, during the process of L. gibbosa growing on wood, gene expression at the transcriptional level indicated that lignin catabolism and hyphal growth were promoted, but the metabolism of carbon and carbohydrates including cellulose in lignocellulose in overall trend was inhibited to some extent. The results have important reference value for the study of degradation mechanism of wood white rot.
2023-09-17 | GSE184416 | GEO
Project description:In contrast to batch cultivation, chemostat cultivation allows the identification of carbon source responses without interference by carbon-catabolite repression, accumulation of toxic products, and differences in specific growth rate. This study focuses on the yeast Saccharomyces cerevisiae, grown in aerobic, carbon-limited chemostat cultures. Genome-wide transcript levels and in vivo fluxes were compared for growth on two sugars, glucose and maltose, and for two C2-compounds, ethanol and acetate. In contrast to previous reports on batch cultures, few genes (180 genes) responded to changes of the carbon source by a changed transcript level. Very few transcript levels were changed when glucose as the growth-limiting nutrient was compared with maltose (33 transcripts), or when acetate was compared with ethanol (16 transcripts). Although metabolic flux analysis using a stoichiometric model revealed major changes in the central carbon metabolism, only 117 genes exhibited a significantly different transcript level when sugars and C2-compounds were provided as the growthlimiting nutrient. Despite the extensive knowledge on carbon source regulation in yeast, many of the carbon source-responsive genes encoded proteins with unknown or incompletely characterized biological functions. In silico promoter analysis of carbon source-responsive genes confirmed the involvement of several known transcriptional regulators and suggested the involvement of additional regulators. Transcripts involved in the glyoxylate cycle and gluconeogenesis showed a good correlation with in vivo fluxes. This correlation was, however, not observed for other important pathways, including the pentose-phosphate pathway, tricarboxylic acid cycle, and, in particular, glycolysis. These results indicate that in vivo fluxes in the central carbon metabolism of S. cerevisiae grown in steadystate, carbon-limited chemostat cultures are controlled to a large extent via post-transcriptional mechanisms. Experiment Overall Design: Cultivation of microorganisms in chemostats offers numerous advantages for studying the structure and regulation of metabolic networks (11). In chemostat cultures, individual culture parameters can be changed, while keeping other relevant physical and chemical culture parameters (composition of synthetic medium, pH, temperature, aeration, etc.) constant. An especially important parameter in this respect is the specific growth rate, which, in a chemostat, is equal to the dilution rate, which can be accurately controlled. This allows the experimenter to investigate the effects of environmental changes or genetic interventions at a fixed specific growth rate, even if these changes result in different specific growth rates in batch cultures. In a chemostat, growth can be limited by a single, selected nutrient. The very low residual concentrations of this growth-limiting nutrient in chemostat cultures alleviate effects of catabolite repression and inactivation. Furthermore, these low residual substrate concentrations prevent substrate toxicity, which, for example, occurs when S. cerevisiae is grown on ethanol or acetate as the carbon source in batch cultures . Experiment Overall Design: The central goal of the present study is to assess to what extent carbon source-dependent regulation of fluxes through central carbon metabolism in S. cerevisiae is regulated at the level of transcription. To this end, we compare the transcriptome of carbon-limited, aerobic chemostat cultures grown on four different carbon sources: glucose, maltose, ethanol, and acetate. Data from the transcriptome analysis are compared with flux distribution profiles calculated with a stoichiometric metabolic network model. Questions that will be addressed are as follows: (i) does glucose-limited aerobic cultivation lead to a complete alleviation of glucose-catabolite repression; (ii) how (in)complete is our understanding of the genes involved in the transcriptional response of S. cerevisiae to four of the most common carbon sources for this yeast; and (iii) to what extent do transcriptome analyses with microarrays provide a reliable indication of flux distribution in metabolic networks?
2008-06-16 | E-GEOD-8895 | biostudies-arrayexpress
Project description:White-rot fungi (WRF), considered the most efficient organisms at degrading organic carbon in the biosphere, are found in plant cell wall lignin biopolymer. We employ multi-omics to demonstrate that Trametes versicolor and Gelatoporia subvermispora funnel lignin-derived aromatic compounds into central carbon metabolism via intracellular catabolic pathways. These results provide insights into global carbon cycling in soil ecosystems.
2021-02-10 | PXD019839 | Pride
Project description:Non-conventional methylotrophic yeast Komagataella phaffii is an important production host in biotechnology and an emerging model organism. In this work, we studied K. phaffii response to nitrogen starvation during cultivation in media with methanol as the sole carbon source. The results were compared with well-established model yeast Saccharomyces cerevisiae. Some of the observed effects of nitrogen starvation in K. phaffii were similar to those in S. cerevisiae, despite this yeast does not have metabolic pathway for methanol utilization. The effects include activation of autophagy, transport and catabolism of nitrogen-containing compounds, interconversions of amino acids, and biosynthesis of fatty acids. K. phaffii cells also demonstrated specific response to nitrogen starvation including suppression of genes involved in methanol metabolism and other peroxisomal processes and activation of purine catabolism genes.
2024-10-06 | GSE278110 | GEO
Project description:Millard2016 - E. coli central carbon and
energy metabolism
This model is described in the article:
Metabolic regulation is
sufficient for global and robust coordination of glucose
uptake, catabolism, energy production and growth in Escherichia
coli
Pierre Millard , Kieran Smallbone,
Pedro Mendes
PLoS ONE
Abstract:
The metabolism of microorganisms is regulated through two
main mechanisms: changes of enzyme capacities as a consequence
of gene expression modulation (“hierarchical
control”) and changes of enzyme activities through
metabolite-enzyme interactions. An increasing body of evidence
indicates that hierarchical control is insufficient to explain
metabolic behaviors, but the system-wide impact of metabolic
regulation remains largely uncharacterized. To clarify its
role, we developed and validated a detailed kinetic model of
Escherichia coli central metabolism that links growth to
environment. Metabolic control analyses confirm that the
control is widely distributed across the network and highlight
strong interconnections between all the pathways. Exploration
of the model solution space reveals that several robust
properties emerge from metabolic regulation, from the molecular
level (e.g. homeostasis of total metabolite pool) to the
overall cellular physiology (e.g. coordination of carbon
uptake, catabolism, energy and redox production, and growth),
while allowing a large degree of flexibility at most individual
metabolic steps. These properties have important physiological
implications for E. coli and significantly expand the
self-regulating capacities of its metabolism.
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2017-02-21 | MODEL1505110000 | BioModels