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1.
Drug Des Devel Ther ; 18: 1165-1174, 2024.
Article En | MEDLINE | ID: mdl-38623566

Purpose: Citric acid (CA) is a tricarboxylic acid with antioxidant and antimicrobial properties. Based on previous studies, the small compound with its three carboxylic groups can be considered a protein tyrosine phosphatase inhibitor. YopH, a protein tyrosine phosphatase, is an essential virulence factor in Yersinia bacteria. Materials and Methods: We performed enzymatic activity assays of YopH phosphatase after treatment with citric acid in comparison with the inhibitory compound trimesic acid, which has a similar structure. We also measured the cytotoxicity of these compounds in Jurkat T E6.1 and macrophage J774.2 cell lines. We performed molecular docking analysis of the binding of citric acid molecules to YopH phosphatase. Results: Citric acid and trimesic acid reversibly reduced the activity of YopH enzyme and decreased the viability of Jurkat and macrophage cell lines. Importantly, these two compounds showed greater inhibitory properties against bacterial YopH activity than against human CD45 phosphatase activity. Molecular docking simulations confirmed that citric acid could bind to YopH phosphatase. Conclusion: Citric acid, a known antioxidant, can be considered an inhibitor of bacterial phosphatases.


Antioxidants , Protein Tyrosine Phosphatases , Tricarboxylic Acids , Humans , Molecular Docking Simulation , Protein Tyrosine Phosphatases/chemistry , Protein Tyrosine Phosphatases/metabolism , Tyrosine
2.
J Plant Physiol ; 294: 154195, 2024 Mar.
Article En | MEDLINE | ID: mdl-38377939

We discuss the role of epigenetic changes at the level of promoter methylation of the key enzymes of carbon metabolism in the regulation of respiration by light. While the direct regulation of enzymes via modulation of their activity and post-translational modifications is fast and readily reversible, the role of cytosine methylation is important for providing a prolonged response to environmental changes. In addition, adenine methylation can play a role in the regulation of transcription of genes. The mitochondrial and extramitochondrial forms of several enzymes participating in the tricarboxylic acid cycle and associated reactions are regulated via promoter methylation in opposite ways. The mitochondrial forms of citrate synthase, aconitase, fumarase, NAD-malate dehydrogenase are inhibited while the cytosolic forms of aconitase, fumarase, NAD-malate dehydrogenase, and the peroxisomal form of citrate synthase are activated. It is concluded that promoter methylation represents a universal mechanism of the regulation of activity of respiratory enzymes in plant cells by light. The role of the regulation of the mitochondrial and cytosolic forms of respiratory enzymes in the operation of malate and citrate valves and in controlling the redox state and balancing the energy level of photosynthesizing plant cells is discussed.


Fumarate Hydratase , Malate Dehydrogenase , Malate Dehydrogenase/genetics , Malate Dehydrogenase/metabolism , Citrate (si)-Synthase/genetics , Citrate (si)-Synthase/metabolism , Fumarate Hydratase/genetics , Tricarboxylic Acids/metabolism , Citric Acid Cycle , Plants/genetics , Plants/metabolism , Aconitate Hydratase/genetics , Aconitate Hydratase/metabolism , DNA Methylation/genetics , Respiration
3.
Appl Environ Microbiol ; 90(2): e0211123, 2024 Feb 21.
Article En | MEDLINE | ID: mdl-38289138

Despite the significant presence of plant-derived tricarboxylic acids in some environments, few studies detail the bacterial metabolism of trans-aconitic acid (Taa) and tricarballylic acid (Tcb). In a soil bacterium, Acinetobacter baylyi ADP1, we discovered interrelated pathways for the consumption of Taa and Tcb. An intricate regulatory scheme tightly controls the transport and catabolism of both compounds and may reflect that they can be toxic inhibitors of the tricarboxylic acid cycle. The genes encoding two similar LysR-type transcriptional regulators, TcuR and TclR, were clustered on the chromosome with tcuA and tcuB, genes required for Tcb consumption. The genetic organization differed from that in Salmonella enterica serovar Typhimurium, in which tcuA and tcuB form an operon with a transporter gene, tcuC. In A. baylyi, tcuC was not cotranscribed with tcuAB. Rather, tcuC was cotranscribed with a gene, designated pacI, encoding an isomerase needed for Taa consumption. TcuC appears to transport Tcb and cis-aconitic acid (Caa), the presumed product of PacI-mediated periplasmic isomerization of Taa. Two operons, tcuC-pacI and tcuAB, were transcriptionally controlled by both TcuR and TclR, which have overlapping functions. We investigated the roles of the two regulators in activating transcription of both operons in response to multiple effector compounds, including Taa, Tcb, and Caa.IMPORTANCEIngestion of Taa and Tcb by grazing livestock can cause a serious metabolic disorder called grass tetany. The disorder, which results from Tcb absorption by ruminants, focuses attention on the metabolism of tricarboxylic acids. Additional interest stems from efforts to produce tricarboxylic acids as commodity chemicals. Improved understanding of bacterial enzymes and pathways for tricarboxylic acid metabolism may contribute to new biomanufacturing strategies.


Acinetobacter , Aconitic Acid , Aconitic Acid/metabolism , Tricarboxylic Acids/chemistry , Tricarboxylic Acids/metabolism , Acinetobacter/genetics , Acinetobacter/metabolism , Salmonella typhimurium/genetics , Bacterial Proteins/metabolism
4.
Bioresour Technol ; 393: 130122, 2024 Feb.
Article En | MEDLINE | ID: mdl-38040309

Aureobasidium pullulans produced poly-L-malic acid (PMA) as the main metabolite in fermentation but with relatively low productivity and yield limiting its industrial application. In this study, A. pullulans ZX-10 was engineered to overexpress cytosolic malate dehydrogenase (MDH) and pyruvate carboxylase (PYC) and PMA synthetase (PMS) using a high-copy yeast episomal plasmid with the gpdA promoter from Aspergillus nidulans. Overexpressing endogenous PMS and heterologous MDH and PYC from Aspergillus oryzae respectively increased PMA production by 19 % - 37 % (0.64 - 0.74 g/g vs. 0.54 g/g for wild type) in shake-flask fermentations, demonstrating the importance of the reductive tricarboxylic acid (rTCA) pathway in PMA biosynthesis. A. pullulans co-expressing MDH and PYC produced 96.7 g/L PMA at 0.90 g/L∙h and 0.68 g/g glucose in fed-batch fermentation, which were among the highest yield and productivity reported. The engineered A. pullulans with enhanced rTCA pathway is advantageous and promising for PMA production.


Aureobasidium , Tricarboxylic Acids , Aureobasidium/metabolism , Fermentation , Malates/metabolism , Saccharomyces cerevisiae/metabolism
5.
mBio ; 15(2): e0308823, 2024 Feb 14.
Article En | MEDLINE | ID: mdl-38126768

Biological nitrogen fixation, the conversion of inert N2 to metabolically tractable NH3, is only performed by certain microorganisms called diazotrophs and is catalyzed by the nitrogenases. A [7Fe-9S-C-Mo-R-homocitrate]-cofactor, designated FeMo-co, provides the catalytic site for N2 reduction in the Mo-dependent nitrogenase. Thus, achieving FeMo-co formation in model eukaryotic organisms, such as Saccharomyces cerevisiae, represents an important milestone toward endowing them with a capacity for Mo-dependent biological nitrogen fixation. A central player in FeMo-co assembly is the scaffold protein NifEN upon which processing of NifB-co, an [8Fe-9S-C] precursor produced by NifB, occurs. Prior work established that NifB-co can be produced in S. cerevisiae mitochondria. In the present work, a library of nifEN genes from diverse diazotrophs was expressed in S. cerevisiae, targeted to mitochondria, and surveyed for their ability to produce soluble NifEN protein complexes. Many such NifEN variants supported FeMo-co formation when heterologously produced in the diazotroph A. vinelandii. However, only three of them accumulated in soluble forms in mitochondria of aerobically cultured S. cerevisiae. Of these, two variants were active in the in vitro FeMo-co synthesis assay. NifEN, NifB, and NifH proteins from different species, all of them produced in and purified from S. cerevisiae mitochondria, were combined to establish successful FeMo-co biosynthetic pathways. These findings demonstrate that combining diverse interspecies nitrogenase FeMo-co assembly components could be an effective and, perhaps, the only approach to achieve and optimize nitrogen fixation in a eukaryotic organism.IMPORTANCEBiological nitrogen fixation, the conversion of inert N2 to metabolically usable NH3, is a process exclusive to diazotrophic microorganisms and relies on the activity of nitrogenases. The assembly of the nitrogenase [7Fe-9S-C-Mo-R-homocitrate]-cofactor (FeMo-co) in a eukaryotic cell is a pivotal milestone that will pave the way to engineer cereals with nitrogen fixing capabilities and therefore independent of nitrogen fertilizers. In this study, we identified NifEN protein complexes that were functional in the model eukaryotic organism Saccharomyces cerevisiae. NifEN is an essential component of the FeMo-co biosynthesis pathway. Furthermore, the FeMo-co biosynthetic pathway was recapitulated in vitro using only proteins expressed in S. cerevisiae. FeMo-co biosynthesis was achieved by combining nitrogenase FeMo-co assembly components from different species, a promising strategy to engineer nitrogen fixation in eukaryotic organisms.


Iron Compounds , Nitrogenase , Saccharomyces cerevisiae , Tricarboxylic Acids , Nitrogenase/metabolism , Saccharomyces cerevisiae/genetics , Saccharomyces cerevisiae/metabolism , Molybdoferredoxin/metabolism , Bacterial Proteins/metabolism , Mitochondria/metabolism , Nitrogen/metabolism
6.
Wiad Lek ; 76(11): 2510-2516, 2023.
Article En | MEDLINE | ID: mdl-38112373

OBJECTIVE: The aim: To determine the efficacy of the original hormone-vitamin complex in terms of biochemical activity enhancement and muscle system functional activity restoration in the irradiated rat's descendents. PATIENTS AND METHODS: Materials and methods: The activity of NADP-dependent malatedehydrogenase and the content of ATP, ADP and AMP were determined in the blood, myocardium and thigh muscles of rats exposed to ionizing gamma-radiation. The rats were also checked in the forced swimming test. The efficacy of the hormone-vitamin complex was determined in all mentioned indexes. RESULTS: Results: Our results testify the expressed changes in muscle tissue functioning in an irradiated person, which was expressed by the dysfunction of biochemical reactions aimed at synthetic energy processes, and by the macroergic compounds level depletion together with physical performance minimization. Our data showed the hormone-vitamin complex injection to irradiated animals and their descendants improved the muscle energy resources due to glycolytic substrate phosphorylation enhancement and due to tricarboxylic acids cycle oxidative potential strengthening. CONCLUSION: Conclusions: Original scheme of post-radiation lesions complex pharmacological correction prevented the development of tissues providing with macroergic compounds, anaerobic processes strengthening, metabolic acidosis, weakening of both substrate phosphorylation and tricarboxylic acids cycle. The original scheme of ionizing radiation-induced energetic disorders pharmacological corrections in the irradiated animals' descendents we consider as an experimental basis for the reasonability of these compound radioprotective effects testing during the physiotherapeutic treatment of persons exposed to ionizing radiation.


Radiation, Ionizing , Vitamins , Humans , Rats , Animals , Muscle, Skeletal , Hormones , Tricarboxylic Acids
7.
Inorg Chem ; 62(48): 19433-19445, 2023 Dec 04.
Article En | MEDLINE | ID: mdl-37987624

Nitrogenase is the only enzyme that can cleave the strong triple bond in N2, making nitrogen available for biological life. There are three isozymes of nitrogenase, differing in the composition of the active site, viz., Mo, V, and Fe-nitrogenase. Recently, the first crystal structure of Fe-nitrogenase was presented. We have performed the first combined quantum mechanical and molecular mechanical (QM/MM) study of Fe-nitrogenase. We show with QM/MM and quantum-refinement calculations that the homocitrate ligand is most likely protonated on the alcohol oxygen in the resting E0 state. The most stable broken-symmetry (BS) states are the same as for Mo-nitrogenase, i.e., the three Noodleman BS7-type states (with a surplus of ß spin on the eighth Fe ion), which maximize the number of nearby antiferromagnetically coupled Fe-Fe pairs. For the E1 state, we find that protonation of the S2B µ2 belt sulfide ion is most favorable, 14-117 kJ/mol more stable than structures with a Fe-bound hydride ion (the best has a hydride ion on the Fe2 ion) calculated with four different density-functional theory methods. This is similar to what was found for Mo-nitrogenase, but it does not explain the recent EPR observation that the E1 state of Fe-nitrogenase should contain a photolyzable hydride ion. For the E1 state, many BS states are close in energy, and the preferred BS state differs depending on the position of the extra proton and which density functional is used.


Nitrogenase , Tricarboxylic Acids , Nitrogenase/chemistry , Protons , Catalytic Domain
8.
Nat Ecol Evol ; 7(9): 1398-1407, 2023 09.
Article En | MEDLINE | ID: mdl-37537385

The reverse tricarboxylic acid (rTCA) cycle is touted as a primordial mode of carbon fixation due to its autocatalytic propensity and oxygen intolerance. Despite this inferred antiquity, however, the earliest rock record affords scant supporting evidence. In fact, based on the chimeric inheritance of rTCA cycle steps within the Chlorobiaceae, even the use of the chemical fossil record of this group is now subject to question. While the 1.64-billion-year-old Barney Creek Formation contains chemical fossils of the earliest known putative Chlorobiaceae-derived carotenoids, interferences from the accompanying hydrocarbon matrix have hitherto precluded the carbon isotope measurements necessary to establish the physiology of the organisms that produced them. Overcoming this obstacle, here we report a suite of compound-specific carbon isotope measurements identifying a cyanobacterially dominated ecosystem featuring heterotrophic bacteria. We demonstrate chlorobactane is 13C-depleted when compared to contemporary equivalents, showing only slight 13C-enrichment over co-existing cyanobacterial carotenoids. The absence of this diagnostic isotopic fingerprint, in turn, confirms phylogenomic hypotheses that call for the late assembly of the rTCA cycle and, thus, the delayed acquisition of autotrophy within the Chlorobiaceae. We suggest that progressive oxygenation of the Earth System caused an increase in the marine sulfate inventory thereby providing the selective pressure to fuel the Neoproterozoic shift towards energy-efficient photoautotrophy within the Chlorobiaceae.


Chlorobi , Cyanobacteria , Chlorobi/chemistry , Chlorobi/metabolism , Tricarboxylic Acids/metabolism , Ecosystem , Carbon Isotopes , Carbon Cycle , Carotenoids/metabolism
9.
Nat Commun ; 14(1): 2567, 2023 05 04.
Article En | MEDLINE | ID: mdl-37142569

Understanding how plants grow is critical for agriculture and fundamental for illuminating principles of multicellular development. Here, we apply desorption electrospray ionization mass spectrometry imaging (DESI-MSI) to the chemical mapping of the developing maize root. This technique reveals a range of small molecule distribution patterns across the gradient of stem cell differentiation in the root. To understand the developmental logic of these patterns, we examine tricarboxylic acid (TCA) cycle metabolites. In both Arabidopsis and maize, we find evidence that elements of the TCA cycle are enriched in developmentally opposing regions. We find that these metabolites, particularly succinate, aconitate, citrate, and α-ketoglutarate, control root development in diverse and distinct ways. Critically, the developmental effects of certain TCA metabolites on stem cell behavior do not correlate with changes in ATP production. These results present insights into development and suggest practical means for controlling plant growth.


Spectrometry, Mass, Electrospray Ionization , Tricarboxylic Acids , Spectrometry, Mass, Electrospray Ionization/methods , Citric Acid Cycle , Diagnostic Imaging , Growth and Development
10.
Crit Rev Biochem Mol Biol ; 58(1): 81-97, 2023 02.
Article En | MEDLINE | ID: mdl-37125817

The tricarboxylic acid (TCA) cycle is a primordial metabolic pathway that is conserved from bacteria to humans. Although this network is often viewed primarily as an energy producing engine fueling ATP synthesis via oxidative phosphorylation, mounting evidence reveals that this metabolic hub orchestrates a wide variety of pivotal biological processes. It plays an important part in combatting cellular stress by modulating NADH/NADPH homeostasis, scavenging ROS (reactive oxygen species), producing ATP by substrate-level phosphorylation, signaling and supplying metabolites to quell a range of cellular disruptions. This review elaborates on how the reprogramming of this network prompted by such abiotic stress as metal toxicity, oxidative tension, nutrient challenge and antibiotic insult is critical for countering these conditions in mostly microbial systems. The cross-talk between the stressors and the participants of TCA cycle that results in changes in metabolite and nucleotide concentrations aimed at combatting the abiotic challenge is presented. The fine-tuning of metabolites mediated by disparate enzymes associated with this metabolic hub is discussed. The modulation of enzymatic activities aimed at generating metabolic moieties dedicated to respond to the cellular perturbation is explained. This ancient metabolic network has to be recognized for its ability to execute a plethora of physiological functions beyond its well-established traditional roles.


Citric Acid Cycle , Metabolic Networks and Pathways , Humans , Reactive Oxygen Species/metabolism , Adenosine Triphosphate/metabolism , Tricarboxylic Acids
11.
Nat Commun ; 14(1): 1091, 2023 02 25.
Article En | MEDLINE | ID: mdl-36841829

Nitrogenase catalyzes the ATP-dependent reduction of dinitrogen to ammonia during the process of biological nitrogen fixation that is essential for sustaining life. The active site FeMo-cofactor contains a [7Fe:1Mo:9S:1C] metallocluster coordinated with an R-homocitrate (HCA) molecule. Here, we establish through single particle cryoEM and chemical analysis of two forms of the Azotobacter vinelandii MoFe-protein - a high pH turnover inactivated species and a ∆NifV variant that cannot synthesize HCA - that loss of HCA is coupled to α-subunit domain and FeMo-cofactor disordering, and formation of a histidine coordination site. We further find a population of the ∆NifV variant complexed to an endogenous protein identified through structural and proteomic approaches as the uncharacterized protein NafT. Recognition by endogenous NafT demonstrates the physiological relevance of the HCA-compromised form, perhaps for cofactor insertion or repair. Our results point towards a dynamic active site in which HCA plays a role in enabling nitrogenase catalysis by facilitating activation of the FeMo-cofactor from a relatively stable form to a state capable of reducing dinitrogen under ambient conditions.


Azotobacter vinelandii , Nitrogenase , Nitrogenase/metabolism , Proteomics , Molybdoferredoxin/chemistry , Molybdoferredoxin/metabolism , Tricarboxylic Acids , Azotobacter vinelandii/metabolism
12.
Int J Mol Sci ; 24(2)2023 Jan 10.
Article En | MEDLINE | ID: mdl-36674898

Exposure to the toxin thioacetamide (TAA) causes acute hepatic encephalopathy (HE), changes in the functioning of systemic organs, and an imbalance in a number of energy metabolites. The deferred effects after acute HE development are poorly understood. The study considers the balance of the tricarboxylic acid (TCA) cycle metabolites in the blood plasma, liver, kidneys, and brain tissues of rats in the post-rehabilitation period. The samples of the control (n = 3) and TAA-induced groups of rats (n = 13) were collected six days after the administration of a single intraperitoneal TAA injection at doses of 200, 400, and 600 mg/kg. Despite the complete physiological recovery of rats by this date, a residual imbalance of metabolites in all the vital organs was noted. The results obtained showed a trend of stabilizing processes in the main organs of the animals and permit the use of these data both for prognostic purposes and the choice of potential therapeutic agents.


Brain Diseases , Hepatic Encephalopathy , Liver Failure, Acute , Rats , Animals , Hepatic Encephalopathy/chemically induced , Thioacetamide/toxicity , Tricarboxylic Acids/metabolism , Liver/metabolism , Liver Failure, Acute/chemically induced , Brain Diseases/metabolism
13.
Int J Biol Macromol ; 227: 685-697, 2023 Feb 01.
Article En | MEDLINE | ID: mdl-36535355

In this work, a novel and efficient magnetic biocatalyst was designed, prepared and identified using cherry tree gum as a biopolymer functionalized with 1,3,5-benzenetricarboxylic acid (gum@Fe3O4@BTA). The obtained biocatalyst was prepared using available and cheap materials in an easy process. This biocatalyst was used as an efficient catalyst with high catalytic activity for the synthesis of a three-component one-pot protocol and four-component one-pot protocol of tetrahydro-4H-chromene derivatives and polyhydroquinoline derivatives in EtOH green solvent under reflux conditions, respectively. The synthesized heterogeneous biocatalysts were identified and analyzed by FT-IR, EDS, FESEM, TGA and XRD techniques. The synthesis of tetrahydro-4H-chromene and polyhydroquinoline derivatives by using this biocatalyst has advantages such as high efficiency, short reaction time, simple work method, absence of dangerous solvents, environmentally friendly conditions, easy separation of the biocatalyst by an external magnet, and the ability reuse for five periods without significant decrease in catalytic activity.


Benzopyrans , Tricarboxylic Acids , Spectroscopy, Fourier Transform Infrared , Solvents , Magnetic Phenomena
14.
Appl Biochem Biotechnol ; 195(2): 1216-1230, 2023 Feb.
Article En | MEDLINE | ID: mdl-36342624

Metal-organic frameworks (MOFs) can be used as the immobilization carriers to protect the physicochemical properties of enzymes and improve their catalytic performance. Herein, we report an in situ co-precipitation method to immobilize lipase from Candida sp. 99-125 in Cu-BTC MOF (BTC = 1, 3, 5-benzene tricarboxylic acid, H3BTC). Characterizations of the immobilized lipase (lipase@Cu-BTC) have confirmed the entrapment of lipase molecules in Cu-BTC MOF. The immobilized lipase has been successfully applied for resolving N-hydroxymethyl vince lactam (N-HMVL) and its catalytic activity is five times that of native enzyme. More importantly, we found that Cu-BTC MOF can afford powerful protection for enzyme in nearly dry organic solvent and endow the immobilized lipase with excellent reusability and storage stability. Our present study may widen the application of immobilized enzyme with MOF as the immobilized carrier.


Lipase , Metal-Organic Frameworks , Lipase/chemistry , Metal-Organic Frameworks/chemistry , Catalysis , Enzymes, Immobilized/chemistry , Tricarboxylic Acids/chemistry
15.
Mol Cell Biochem ; 478(8): 1669-1687, 2023 Aug.
Article En | MEDLINE | ID: mdl-36495372

The sodium dependent SLC13 family transporters comprise of five genes SLC13A1, SLC13A2 (NaDC1), SLC13A3 (NaDC3), SLC13A4 and SLC13A5 (NaCT). Among them, NaDC1, NaDC3 and NaCT are sodium dependent transporters belonging to family of dicarboxylates (succinate, malate, α-ketoglutarate) and tricarboxylates (citrate). The mouse and the human NaCT structures have still not been crystallized, therefore structural information is taken from the related bacterial transporter of VcINDY. Citrate in the cytosol works as a precursor for the fatty acid synthesis, cholesterol, and low-density lipoproteins. The excess citrate from the matrix is translocated to the cytosol for fatty acid synthesis through these transporters and thus controls the energy balance by downregulating the glycolysis, tricarboxylic acid (TCA), and fatty acid breakdown. These transporters play an important role in regulating various metabolic diseases including cancer, diabetes, obesity, fatty liver diseases and CNS disorders. These di and tricarboxylate transporters are emerging as new targets for metabolic disorders such as obesity and diabetes. The mutation in the function of the NaCT causes several neurological diseases including neonatal epilepsy and impaired brain development whereas mutation of genes coding for citrate transport present in the liver may provide positive effect. Therefore, continued efforts from the earlier work on citrate transporters are required for the development of citrate inhibitors. This review discusses the structure, function, and regulation of the NaCT transporter. The review also highlights citrate role in diagnosing diseases such as cancer, diabetes, fatty liver, and diabetes. The therapeutic perspective of synthetic inhibitors against NaCT transporters is succinctly summarized.


Metabolic Diseases , Symporters , Animals , Mice , Humans , Sodium , Citrates , Citric Acid/metabolism , Membrane Transport Proteins , Tricarboxylic Acids , Metabolic Diseases/drug therapy , Metabolic Diseases/genetics , Obesity , Fatty Acids , Symporters/genetics , Sulfate Transporters
16.
J Bacteriol ; 204(12): e0028422, 2022 12 20.
Article En | MEDLINE | ID: mdl-36321838

Tricarboxylates such as citrate are the preferred carbon sources for Pseudomonas aeruginosa, an opportunistic pathogen that causes chronic human infections. However, the membrane transport process for the tricarboxylic acid cycle intermediates citrate and cis-aconitate is poorly characterized. Transport is thought to be controlled by the TctDE two-component system, which mediates transcription of the putative major transporter OpdH. Here, we search for previously unidentified transporters of citrate and cis-aconitate using both protein homology and RNA sequencing approaches. We uncover new transporters and show that OpdH is not the major citrate importer; instead, citrate transport primarily relies on the tripartite TctCBA system, which is encoded in the opdH operon. Deletion of tctA causes a growth lag on citrate and loss of growth on cis-aconitate. Combinatorial deletion of newly discovered transporters can fully block citrate utilization. We then characterize transcriptional control of the opdH operon in tctDE mutants and show that loss of tctD blocks citrate utilization due to an inability to express opdH-tctCBA. However, tctE and tctDE mutants evolve heritable adaptations that restore growth on citrate as the sole carbon source. IMPORTANCE Pseudomonas aeruginosa is a bacterium that infects hospitalized patients and is often highly resistant to antibiotic treatment. It preferentially uses small organic acids called tricarboxylates rather than sugars as a source of carbon for growth. The transport of many of these molecules from outside the cell to the interior occurs through unknown channels. Here, we examined how the tricarboxylates citrate and cis-aconitate are transported in P. aeruginosa. We then sought to understand how production of proteins that permit citrate and cis-aconitate transport is regulated by a signaling system called TctDE. We identified new transporters for these molecules, clarified the function of a known transport system, and directly tied transporter expression to the presence of an intact TctDE system.


Citric Acid , Pseudomonas aeruginosa , Aconitic Acid/metabolism , Carbon/metabolism , Citrates/metabolism , Citric Acid/metabolism , Membrane Transport Proteins/genetics , Membrane Transport Proteins/metabolism , Pseudomonas aeruginosa/genetics , Pseudomonas aeruginosa/metabolism , Tricarboxylic Acids/metabolism
17.
Front Endocrinol (Lausanne) ; 13: 1021263, 2022.
Article En | MEDLINE | ID: mdl-36237186

In recent years, the impact of lipotoxicity on male fertility has received extensive attention, especially on Sertoli cells (SCs). In SCs, energy metabolism is important as disorders of energy metabolism result in infertility eventually. However, the underlying mechanism of lipotoxicity on energy metabolism in SCs remains unknown. Advances in high-throughput metabolomics and lipidomics measurement platforms provide powerful tools to gain insights into complex biological systems. Here, we aimed to explore the potential molecular mechanisms of palmitic acid (PA) regulating energy metabolism in SCs based on metabolomics and lipidomics. The results showed that glucose metabolism-related metabolites were not significantly changed, which suggested that PA treatment had little effect on glucose metabolism and may not influence the normal energy supply from SCs to germ cells. However, fatty acid ß-oxidation was inhibited according to accumulation of medium- and long-chain acylcarnitines in cells. In addition, the pool of amino acids and the levels of most individual amino acids involved in the tricarboxylic acid (TCA) cycle were not changed after PA treatment in SCs. Moreover, PA treatment of SCs significantly altered the lipidome, including significant decreases in cardiolipin and glycolipids as well as remarkable increases in ceramide and lysophospholipids, which indicated that mitochondrial function was affected and apoptosis was triggered. The increased apoptosis rate of SCs was verified by elevated protein expression levels of Cleaved Caspase-3 and Bax as well as decreased Bcl-2 protein expression level. Together, these findings indicated that PA may result in mitochondrial dysfunction and increased apoptosis by inhibiting fatty acid ß-oxidation of SCs.


Palmitic Acid , Sertoli Cells , Amino Acids/metabolism , Apoptosis , Cardiolipins/metabolism , Cardiolipins/pharmacology , Caspase 3/metabolism , Caspase 3/pharmacology , Ceramides/metabolism , Glucose/metabolism , Glycolipids/metabolism , Humans , Lysophospholipids/metabolism , Lysophospholipids/pharmacology , Male , Mitochondria/metabolism , Palmitic Acid/pharmacology , Tricarboxylic Acids/metabolism , Tricarboxylic Acids/pharmacology , bcl-2-Associated X Protein/metabolism , bcl-2-Associated X Protein/pharmacology
18.
Front Immunol ; 13: 974034, 2022.
Article En | MEDLINE | ID: mdl-36203594

Cuproptosis, Copper Induced Cell Death, is a newly defined type of programmed cell death, involving in the regulation of tricarboxylic acid (TCA) cycle. Dysfunction of cuproptosis induces cytotoxicity and influences the proliferation of multiple tumors. However, the direct prognostic effect of cuproptosis related genes and corresponding regulating mechanisms amid prostate cancer remains unknown. A multi-omics analysis strategy was adopted to explore the role of ten cuproptosis related genes in The Cancer Genome Atlas- Prostate Adenocarcinoma (TCGA-PRAD). Firstly, mRNA expression, Copy Number Variance (CNV), mutation, DNA methylation and prognostic power of the ten genes were illustrated. Based on transcriptomic data, we developed a novel prognostic model named the Cuproptosis-related gene score (CRGScore), Their biological functions were then detected by enrichment analysis and unsupervised cluster analysis. Following that, their correlation with Tumor Immune Microenvironment (TIME), immunotherapy, Biochemical Recurrence (BCR) and chemotherapeutic resistance were elaborated by relevant bioinformatics algorithms. Ten cuproptosis related genes exhibited extensive alteration of CNV and DNA methylation and showed significant influence on the prognosis of prostate cancer patients. These genes mainly enriched in E2F and G2M targets and mitosis pathways, Samples with high CRGScore showed enhancement resulting in the increased infiltration of T cell, B cell, NK cells. They also demonstrated close correlations with the BCR status, expression of eight immune checkpoints and chemotherapeutic resistances in prostate cancer. Our comprehensive analysis of CRGScore revealed an extensive regulatory mechanism by which they affect the tumor-immune-stromal microenvironment, clinicopathological features, and prognosis. We also determined the therapeutic liability of CRGScore in targeted therapy and immunotherapy. These findings highlight the crucial clinical implications of CRGScore and provide new ideas for guiding personalized immunotherapy strategies for patients with Pca.


Apoptosis , Prostatic Neoplasms , Tumor Microenvironment , Humans , Male , Copper , Prognosis , RNA, Messenger , Tricarboxylic Acids , Tumor Microenvironment/genetics
19.
PLoS One ; 17(10): e0275539, 2022.
Article En | MEDLINE | ID: mdl-36227849

The geological record of microbial metabolisms and ecologies primarily consists of stable isotope fractionations and the diagenetic products of biogenic lipids. Carotenoid lipid biomarkers are particularly useful proxies for reconstructing this record, providing information on microbial phototroph primary productivity, redox couples, and oxygenation. The biomarkers okenane, chlorobactane, and isorenieratene are generally considered to be evidence of anoxygenic phototrophs, and provide a record that extends to 1.64 Ga. The utility of the carotenoid biomarker record may be enhanced by examining the carbon isotopic ratios in these products, which are diagnostic for specific pathways of biological carbon fixation found today within different microbial groups. However, this joint inference assumes that microbes have conserved these pathways across the duration of the preserved biomarker record. Testing this hypothesis, we performed phylogenetic analyses of the enzymes constituting the reductive tricarboxylic acid (rTCA) cycle in Chlorobiales, the group of anoxygenic phototrophic bacteria usually implicated in the deposition of chlorobactane and isorenieretane. We find phylogenetically incongruent patterns of inheritance across all enzymes, indicative of horizontal gene transfers to both stem and crown Chlorobiales from multiple potential donor lineages. This indicates that a complete rTCA cycle was independently acquired at least twice within Chlorobiales and was not present in the last common ancestor. When combined with recent molecular clock analyses, these results predict that the Mesoproterzoic lipid biomarker record diagnostic for Chlorobiales should not preserve isotopic fractionations indicative of a full rTCA cycle. Furthermore, we conclude that coupling isotopic and biomarker records is insufficient for reliably reconstructing microbial paleoecologies in the absence of a complementary and consistent phylogenomic narrative.


Chlorobi , Autotrophic Processes , Biomarkers/metabolism , Carbon Cycle , Carbon Isotopes/analysis , Carotenoids/metabolism , Lipids/genetics , Phylogeny , Tricarboxylic Acids/metabolism
20.
Front Immunol ; 13: 912579, 2022.
Article En | MEDLINE | ID: mdl-36189213

Background: Coronavirus-19 (COVID-19) disease is driven by an unchecked immune response to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus which alters host mitochondrial-associated mechanisms. Compromised mitochondrial health results in abnormal reprogramming of glucose metabolism, which can disrupt extracellular signalling. We hypothesized that examining mitochondrial energy-related signalling metabolites implicated in host immune response to SARS-CoV-2 infection would provide potential biomarkers for predicting the risk of severe COVID-19 illness. Methods: We used a semi-targeted serum metabolomics approach in 273 patients with different severity grades of COVID-19 recruited at the acute phase of the infection to determine the relative abundance of tricarboxylic acid (Krebs) cycle-related metabolites with known extracellular signaling properties (pyruvate, lactate, succinate and α-ketoglutarate). Abundance levels of energy-related metabolites were evaluated in a validation cohort (n=398) using quantitative fluorimetric assays. Results: Increased levels of four energy-related metabolites (pyruvate, lactate, a-ketoglutarate and succinate) were found in critically ill COVID-19 patients using semi-targeted and targeted approaches (p<0.05). The combined strategy proposed herein enabled us to establish that circulating pyruvate levels (p<0.001) together with body mass index (p=0.025), C-reactive protein (p=0.039), D-Dimer (p<0.001) and creatinine (p=0.043) levels, are independent predictors of critical COVID-19. Furthermore, classification and regression tree (CART) analysis provided a cut-off value of pyruvate in serum (24.54 µM; p<0.001) as an early criterion to accurately classify patients with critical outcomes. Conclusion: Our findings support the link between COVID-19 pathogenesis and immunometabolic dysregulation, and show that fluorometric quantification of circulating pyruvate is a cost-effective clinical decision support tool to improve patient stratification and prognosis prediction.


COVID-19 , Biomarkers , C-Reactive Protein , Creatinine , Glucose , Humans , Ketoglutaric Acids , Lactates , Prognosis , Pyruvic Acid , SARS-CoV-2 , Succinates , Tricarboxylic Acids
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