scholarly journals 3-Hydroxyisobutyryl-CoA hydrolase involved in isoleucine catabolism regulates triacylglycerol accumulation in Phaeodactylum tricornutum

2017 ◽  
Vol 372 (1728) ◽  
pp. 20160409 ◽  
Author(s):  
Yufang Pan ◽  
Juan Yang ◽  
Yangmin Gong ◽  
Xiaolong Li ◽  
Hanhua Hu
Keyword(s):  
Phaeodactylum Tricornutum ◽  
Profile Analysis ◽  
Tricarboxylic Acid Cycle ◽  
Metabolite Profile ◽  
Degradation Pathway ◽  
High Lipid ◽  
Neutral Lipid Content ◽  
Branched Chain ◽  
Triacylglycerol Accumulation ◽  
Coa Hydrolase

Since methylmalonyl-CoA epimerase appears to be absent in the majority of photosynthetic organisms, including diatoms, (S)-methylmalonyl-CoA, the intermediate of isoleucine (Ile) catabolism, cannot be metabolized to (R)-methylmalonyl-CoA then to succinyl-CoA. In this study, propionyl-CoA carboxylase ( PCC ) RNAi silenced strains and 3-hydroxyisobutyryl-CoA hydrolase ( HIBCH ) overexpression strains were constructed to elucidate the Ile degradation pathway and its influence on lipid accumulation in Phaeodactylum tricornutum based on growth, neutral lipid content and metabolite profile analysis. Knockdown of PCC disturbed the metabolism of Ile through propionyl-CoA to methylmalonyl-CoA, as illustrated by much higher Ile content at day 6. However, Ile decreased to comparable levels to the wild-type at day 10. PCC silencing redirected propionyl-CoA to acetyl-CoA via a modified β-oxidation pathway, and transcript levels for some branched-chain amino acid (BCAA) degradation-related genes, especially HIBCH , significantly upregulated in the PCC mutant, which enhanced the BCAA degradations and thus resulted in higher triacylglycerol (TAG) content. Overexpression of HIBCH accelerates Ile degradation and results in a lowered Ile content in the overexpression strains, thus enhancing carbon skeletons to the tricarboxylic acid cycle and giving rise to increasing TAG accumulation. Our study provides a good strategy to obtain high-lipid-yield transgenic diatoms by modifying the propionyl-CoA metabolism. This article is part of the themed issue ‘The peculiar carbon metabolism in diatoms’.

scholarly journals Integrated multi-omics investigations reveal the key role of synergistic microbial networks in removing plasticizer di-(2-ethylhexyl) phthalate from estuarine sediments

2021 ◽  
Author(s):  
Sean Ting-Shyang Wei ◽  
Yi-Lung Chen ◽  
Yu-Wei Wu ◽  
Tien-Yu Wu ◽  
Yi-Li Lai ◽  
...  
Keyword(s):  
Phthalic Acid ◽  
Profile Analysis ◽  
Metabolite Profile ◽  
Degradation Pathway ◽  
Estuarine Sediments ◽  
Side Chain ◽  
Side Chains ◽  
Human Beings ◽  
Alkyl Side Chains ◽  
Ethylhexyl Phthalate

Di-(2-ethylhexyl) phthalate (DEHP) is the most widely used plasticizer worldwide with an annual global production of over eight million tons. Because of its improper disposal, endocrine-disrupting DEHP often accumulates in estuarine sediments in industrialized countries at sub-millimolar levels, resulting in adverse effects on both ecosystems and human beings. The microbial degraders and biodegradation pathways of DEHP in O2-limited estuarine sediments remain elusive. Here, we employed an integrated meta-omics approach to identify the DEHP degradation pathway and major degraders in this ecosystem. Estuarine sediments were treated with DEHP or its derived metabolites, o-phthalic acid and benzoic acid. The rate of DEHP degradation in denitrifying mesocosms was two times slower than that of o-phthalic acid, suggesting that side-chain hydrolysis of DEHP is the rate-limiting step of anaerobic DEHP degradation. On the basis of microbial community structures, functional gene expression, and metabolite profile analysis, we proposed that DEHP biodegradation in estuarine sediments is mainly achieved through synergistic networks between denitrifying proteobacteria. Acidovorax and Sedimenticola are the major degraders of DEHP side-chains; the resulting o-phthalic acid is mainly degraded by Aestuariibacter through the UbiD-dependent benzoyl-CoA pathway. We isolated and characterized Acidovorax sp. strain 210-6 and its extracellular hydrolase, which hydrolyzes both alkyl side-chains of DEHP. Interestingly, genes encoding DEHP/MEHP hydrolase and phthaloyl-CoA decarboxylase—key enzymes for side-chain hydrolysis and o-phthalic acid degradation, respectively—are flanked by transposases in these proteobacterial genomes, indicating that DEHP degradation capacity is likely transferred horizontally in microbial communities.

scholarly journals PSIV-B-34 Late-Breaking: Targeted metabolomics analysis reveals that dietary super-nutritional selenium regulates energy metabolism homeostasis in pig liver

2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 328-329
Author(s):  
Junmin Zhang ◽  
Chaohua Tang ◽  
Kai Zhang
Keyword(s):  
Energy Metabolism ◽  
Mrna Expression ◽  
Redox State ◽  
Profile Analysis ◽  
Tricarboxylic Acid Cycle ◽  
Basal Diet ◽  
Metabolite Profile ◽  
Pentose Phosphate ◽  
Pig Liver ◽  
Treatment Groups

Abstract Energy metabolism is a major mechanism of power reduction needed to maintain the redox state in an organism. By using a selenium (Se)-deficiency model we have previously demonstrated that Se can shift glycolysis by regulating the redox state in pig skeletal muscle. How dietary super-nutritional Se affects the energy metabolism in pig liver remains unknown. In the present study, super-nutritional Se supplementation (as selenomethionine) effects on liver selenoprotein expression and energy metabolite profiles in pigs were evaluated. In total, 36 castrated male pigs (Duroc × Landrace × Yorkshire, 62.3 ± 3.3 kg) were randomly assigned to two treatment groups with six replicates of three pigs per replicate. The two treatment groups received the same basal diet supplemented with different levels of selenomethionine: Se adequate (Se-A, 0.25 mg Se/kg) and Se supra-nutritional (2.5 mg Se/kg) for 60 days. Animals were then scarified and their livers were sampled for Se content, selenotranscriptome, and energy-targeted metabolite profile analysis. Super-nutritional Se supplementation increased the levels of serum fasting glucose, insulin, and free fatty acid levels (P < 0.05), as well as elevated the total Se liver content (P < 0.05). Glutathione peroxidase 4 mRNA expression was upregulated, while thioredoxin reductase 1 and selenoprotein W mRNA expression levels were downregulated in the super-nutritional Se group. LC-MS-based target metabolomics showed that high Se supplementation increased the levels of most metabolites involved in glycolysis, pentose phosphate pathway, tricarboxylic acid cycle, and acylcarnitine metabolism. These results indicated that dietary super-nutritional Se can regulate energy metabolism homeostasis in the pig liver.

scholarly journals Oxidative Stress-Induced Alteration of Plant Central Metabolism

Life ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 304
Author(s):  
Tatyana Savchenko ◽  
Konstantin Tikhonov
Keyword(s):  
Oxidative Stress ◽  
Stress Responses ◽  
Tricarboxylic Acid Cycle ◽  
Strong Dependence ◽  
Plant Stress ◽  
Metabolite Profile ◽  
Agricultural Practice ◽  
Central Metabolism ◽  
Metabolic Markers ◽  
Sugar Derivatives

Oxidative stress is an integral component of various stress conditions in plants, and this fact largely determines the substantial overlap in physiological and molecular responses to biotic and abiotic environmental challenges. In this review, we discuss the alterations in central metabolism occurring in plants experiencing oxidative stress. To focus on the changes in metabolite profile associated with oxidative stress per se, we primarily analyzed the information generated in the studies based on the exogenous application of agents, inducing oxidative stress, and the analysis of mutants displaying altered oxidative stress response. Despite of the significant variation in oxidative stress responses among different plant species and tissues, the dynamic and transient character of stress-induced changes in metabolites, and the strong dependence of metabolic responses on the intensity of stress, specific characteristic changes in sugars, sugar derivatives, tricarboxylic acid cycle metabolites, and amino acids, associated with adaptation to oxidative stress have been detected. The presented analysis of the available data demonstrates the oxidative stress-induced redistribution of metabolic fluxes targeted at the enhancement of plant stress tolerance through the prevention of ROS accumulation, maintenance of the biosynthesis of indispensable metabolites, and production of protective compounds. This analysis provides a theoretical basis for the selection/generation of plants with improved tolerance to oxidative stress and the development of metabolic markers applicable in research and routine agricultural practice.

scholarly journals Novel Pathway for the Degradation of 2-Chloro-4-Nitrobenzoic Acid by Acinetobacter sp. Strain RKJ12

2011 ◽  
Vol 77 (18) ◽  
pp. 6606-6613 ◽  
Author(s):  
Dhan Prakash ◽  
Ravi Kumar ◽  
R. K. Jain ◽  
B. N. Tiwary
Keyword(s):  
Salicylic Acid ◽  
Tricarboxylic Acid Cycle ◽  
Sole Source ◽  
Degradation Pathway ◽  
Ring Cleavage ◽  
Muconic Acid ◽  
Content Type ◽  
Nitrobenzoic Acid ◽  
Catabolic Genes ◽  
Catechol 1,2 Dioxygenase

ABSTRACTThe organismAcinetobactersp. RKJ12 is capable of utilizing 2-chloro-4-nitrobenzoic acid (2C4NBA) as a sole source of carbon, nitrogen, and energy. In the degradation of 2C4NBA by strain RKJ12, various metabolites were isolated and identified by a combination of chromatographic, spectroscopic, and enzymatic activities, revealing a novel assimilation pathway involving both oxidative and reductive catabolic mechanisms. The metabolism of 2C4NBA was initiated by oxidativeorthodehalogenation, leading to the formation of 2-hydroxy-4-nitrobenzoic acid (2H4NBA), which subsequently was metabolized into 2,4-dihydroxybenzoic acid (2,4-DHBA) by a mono-oxygenase with the concomitant release of chloride and nitrite ions. Stoichiometric analysis indicated the consumption of 1 mol O2per conversion of 2C4NBA to 2,4-DHBA, ruling out the possibility of two oxidative reactions. Experiments with labeled H218O and18O2indicated the involvement of mono-oxygenase-catalyzed initial hydrolytic dechlorination and oxidative denitration mechanisms. The further degradation of 2,4-DHBA then proceeds via reductive dehydroxylation involving the formation of salicylic acid. In the lower pathway, the organism transformed salicylic acid into catechol, which was mineralized by theorthoring cleavage catechol-1,2-dioxygenase tocis, cis-muconic acid, ultimately forming tricarboxylic acid cycle intermediates. Furthermore, the studies carried out on a 2C4NBA−derivative and a 2C4NBA+transconjugant demonstrated that the catabolic genes for the 2C4NBA degradation pathway possibly reside on the ∼55-kb transmissible plasmid present in RKJ12.

scholarly journals Maintenance Role of a Glutathionyl-Hydroquinone Lyase (PcpF) in Pentachlorophenol Degradation by Sphingobium chlorophenolicum ATCC 39723

2008 ◽  
Vol 190 (23) ◽  
pp. 7595-7600 ◽  
Author(s):  
Yan Huang ◽  
Randy Xun ◽  
Guanjun Chen ◽  
Luying Xun
Keyword(s):  
Degradation Rate ◽  
Tricarboxylic Acid Cycle ◽  
Degradation Pathway ◽  
Tricarboxylic Acid ◽  
Metabolic Intermediate ◽  
Reductive Dehalogenase ◽  
Cell Extracts ◽  
Toxic Pollutant ◽  
Sphingobium Chlorophenolicum

ABSTRACT Pentachlorophenol (PCP) is a toxic pollutant. Its biodegradation has been extensively studied in Sphingobium chlorophenolicum ATCC 39723. All enzymes required to convert PCP to a common metabolic intermediate before entering the tricarboxylic acid cycle have been characterized. One of the enzymes is tetrachloro-p-hydroquinone (TeCH) reductive dehalogenase (PcpC), which is a glutathione (GSH) S-transferase (GST). PcpC catalyzes the GSH-dependent conversion of TeCH to trichloro-p-hydroquinone (TriCH) and then to dichloro-p-hydroquinone (DiCH) in the PCP degradation pathway. PcpC is susceptible to oxidative damage, and the damaged PcpC produces glutathionyl (GS) conjugates, GS-TriCH and GS-DiCH, which cannot be further metabolized by PcpC. The fate and effect of GS-hydroquinone conjugates were unknown. A putative GST gene (pcpF) is located next to pcpC on the bacterial chromosome. The pcpF gene was cloned, and the recombinant PcpF was purified. The purified PcpF was able to convert GS-TriCH and GS-DiCH conjugates to TriCH and DiCH, respectively. The GS-hydroquinone lyase reactions catalyzed by PcpF are rather unusual for a GST. The disruption of pcpF in S. chlorophenolicum made the mutant lose the GS-hydroquinone lyase activities in the cell extracts. The mutant became more sensitive to PCP toxicity and had a significantly decreased PCP degradation rate, likely due to the accumulation of the GS-hydroquinone conjugates inside the cell. Thus, PcpF played a maintenance role in PCP degradation and converted the GS-hydroquinone conjugates back to the intermediates of the PCP degradation pathway.

scholarly journals Investigating mixotrophic metabolism in the model diatom Phaeodactylum tricornutum

2017 ◽  
Vol 372 (1728) ◽  
pp. 20160404 ◽  
Author(s):  
Valeria Villanova ◽  
Antonio Emidio Fortunato ◽  
Dipali Singh ◽  
Davide Dal Bo ◽  
Melissa Conte ◽  
...  
Keyword(s):  
Lipid Metabolism ◽  
Phaeodactylum Tricornutum ◽  
Photosynthetic Activity ◽  
Biomass Accumulation ◽  
Point Of View ◽  
Physiological Data ◽  
Pennate Diatom ◽  
Metabolic Modelling ◽  
Central Carbon ◽  
Triacylglycerol Accumulation

Diatoms are prominent marine microalgae, interesting not only from an ecological point of view, but also for their possible use in biotechnology applications. They can be cultivated in phototrophic conditions, using sunlight as the sole energy source. Some diatoms, however, can also grow in a mixotrophic mode, wherein both light and external reduced carbon contribute to biomass accumulation. In this study, we investigated the consequences of mixotrophy on the growth and metabolism of the pennate diatom Phaeodactylum tricornutum , using glycerol as the source of reduced carbon. Transcriptomics, metabolomics, metabolic modelling and physiological data combine to indicate that glycerol affects the central-carbon, carbon-storage and lipid metabolism of the diatom. In particular, provision of glycerol mimics typical responses of nitrogen limitation on lipid metabolism at the level of triacylglycerol accumulation and fatty acid composition. The presence of glycerol, despite provoking features reminiscent of nutrient limitation, neither diminishes photosynthetic activity nor cell growth, revealing essential aspects of the metabolic flexibility of these microalgae and suggesting possible biotechnological applications of mixotrophy. This article is part of the themed issue ‘The peculiar carbon metabolism in diatoms'.

scholarly journals Associations Between Dietary Protein Sources, Plasma BCAA and Short-Chain Acylcarnitine Levels in Adults

Nutrients ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 173 ◽  
Author(s):  
Michèle Rousseau ◽  
Frédéric Guénard ◽  
Véronique Garneau ◽  
Bénédicte Allam-Ndoul ◽  
Simone Lemieux ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Dietary Protein ◽  
Metabolite Profile ◽  
Branched Chain Amino Acids ◽  
Normal Weight ◽  
Animal Protein ◽  
Elevated Plasma ◽  
Men And Women ◽  
Protein Sources ◽  
Branched Chain

Elevated plasma branched-chain amino acids (BCAA) and C3 and C5 acylcarnitines (AC) levels observed in individuals with insulin resistance (IR) might be influenced by dietary protein intakes. This study explores the associations between dietary protein sources, plasma BCAA levels and C3 and C5 ACs in normal weight (NW) or overweight (OW) individuals with or without metabolic syndrome (MS). Data from 199 men and women aged 18–55 years with complete metabolite profile were analyzed. Associations between metabolic parameters, protein sources, plasma BCAA and AC levels were tested. OW/MS+ consumed significantly more animal protein (p = 0.0388) and had higher plasma BCAA levels (p < 0.0001) than OW/MS− or NW/MS− individuals. Plasma BCAA levels were not associated with BCAA intakes in the whole cohort, while there was a trend for an association between plasma BCAA levels and red meat or with animal protein in OW/MS+. These associations were of weak magnitude. In NW/MS− individuals, the protein sources associated with BCAA levels varied greatly with adjustment for confounders. Plasma C3 and C5 ACs were associated with plasma BCAA levels in the whole cohort (p < 0.0001) and in subgroups based on OW and MS status. These results suggest a modest association of meat or animal protein intakes and an association of C3 and C5 ACs with plasma BCAA levels, obesity and MS.

scholarly journals GC-MS Metabolite Profile and Identification of Unusual Homologous Cannabinoids in High Potency Cannabis sativa

Planta Medica ◽  
2020 ◽  
Vol 86 (05) ◽  
pp. 338-347 ◽  
Author(s):  
Josep Basas-Jaumandreu ◽  
F. Xavier C. de las Heras
Keyword(s):  
Cannabis Sativa ◽  
Metabolite Profile ◽  
Side Chain ◽  
High Potency ◽  
Double Bond Migration ◽  
Phytochemical Investigation ◽  
Branched Chain ◽  
Fragmentation Patterns ◽  
Cis And Trans ◽  
Tms Derivatives

AbstractPhytochemical investigation of the lipids extracted from seeds of Cannabis sativa by GC-MS showed 43 cannabinoids, 16 of which are new. The extract is dominated by Δ9-tetrahydrocannabinolic acid (A) and its neutral derivative trans-Δ9-tetrahydrocannabinol-C5 (THC) Cis and trans-Δ9-tetrahydrocannabinol-C7 isomers with an ethyl-pentyl branched chain together with minor amounts of trans-Δ9-tetrahydrocannabinol with a methyl-pentyl C6 branched side chain were identified as new natural compounds. Four cannabichromene isomers with a C5 side chain are postulated to be derived from the double bond migration at the terminal isoprenyl unit. C7 cannabichromene together with the neutral and acidic forms of cannabinol-C7 were also detected. The mass spectrum of these homologues as trimethylsilyl (TMS) derivatives are presented, and the fragmentation patterns are discussed.

scholarly journals Effect of renal tubule-specific knockdown of the Na+/H+exchanger NHE3 in Akita diabetic mice

2019 ◽  
Vol 317 (2) ◽  
pp. F419-F434 ◽  
Author(s):  
Akira Onishi ◽  
Yiling Fu ◽  
Manjula Darshi ◽  
Maria Crespo-Masip ◽  
Winnie Huang ◽  
...  
Keyword(s):  
Amino Acids ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Tricarboxylic Acid Cycle ◽  
Branched Chain Amino Acids ◽  
Tricarboxylic Acid ◽  
Proximal Tubules ◽  
Wild Type ◽  
Kidney Weight ◽  
Acid Cycle ◽  
Branched Chain

Na+/H+exchanger isoform 3 (NHE3) contributes to Na+/bicarbonate reabsorption and ammonium secretion in early proximal tubules. To determine its role in the diabetic kidney, type 1 diabetic Akita mice with tubular NHE3 knockdown [Pax8-Cre; NHE3-knockout (KO) mice] were generated. NHE3-KO mice had higher urine pH, more bicarbonaturia, and compensating increases in renal mRNA expression for genes associated with generation of ammonium, bicarbonate, and glucose (phosphoenolpyruvate carboxykinase) in proximal tubules and H+and ammonia secretion and glycolysis in distal tubules. This left blood pH and bicarbonate unaffected in nondiabetic and diabetic NHE3-KO versus wild-type mice but was associated with renal upregulation of proinflammatory markers. Higher renal phosphoenolpyruvate carboxykinase expression in NHE3-KO mice was associated with lower Na+-glucose cotransporter (SGLT)2 and higher SGLT1 expression, indicating a downward tubular shift in Na+and glucose reabsorption. NHE3-KO was associated with lesser kidney weight and glomerular filtration rate (GFR) independent of diabetes and prevented diabetes-associated albuminuria. NHE3-KO, however, did not attenuate hyperglycemia or prevent diabetes from increasing kidney weight and GFR. Higher renal gluconeogenesis may explain similar hyperglycemia despite lower SGLT2 expression and higher glucosuria in diabetic NHE3-KO versus wild-type mice; stronger SGLT1 engagement could have affected kidney weight and GFR responses. Chronic kidney disease in humans is associated with reduced urinary excretion of metabolites of branched-chain amino acids and the tricarboxylic acid cycle, a pattern mimicked in diabetic wild-type mice. This pattern was reversed in nondiabetic NHE3-KO mice, possibly reflecting branched-chain amino acids use for ammoniagenesis and tricarboxylic acid cycle upregulation to support formation of ammonia, bicarbonate, and glucose in proximal tubule. NHE3-KO, however, did not prevent the diabetes-induced urinary downregulation in these metabolites.

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