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1.
Bioresour Technol ; 413: 131493, 2024 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-39284374

RESUMO

The 5-hydroxyectoine is a natural protective agent with long-lasting moisturising and radiation resistance properties. It can be naturally synthesized by some extremophiles using the "bacterial milking" process, but this can corrode bioreactors and downstream purification may cause environmental pollution. In this study, an engineered Escherichia coli (E. coli) strain was constructed for the 5-hydroxyectoine production. First, three ectoine hydroxylases were characterised and the enzyme from Halomonas elongata was the most effective. The L-2,4-diaminobutyrate transaminase mutant was introduced into the engineered strain, which could accumulate 2.8 g/L 5-hydroxyectoine in shake flasks. By activating the glyoxylate cycle and balancing the α-ketoglutarate distribution, the 5-hydroxyectoine titer was further increased to 3.4 g/L. Finally, the optimized strain synthesized 58 g/L 5-hydroxyectoine via a semi-continuous feeding process in a NaCl-free medium. Overall, this study reported the highest titer of 5-hydroxyectoine synthesized by E. coli and established a low-salt fermentation process through the aforementioned efforts.

2.
J Cell Physiol ; : e31394, 2024 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-39238268

RESUMO

Colon cancer is on the rise in younger adults. Despite multimodal treatment strategies, clinical outcomes in advanced stage colon cancer patients remain poor. Neoadjuvant/adjuvant chemotherapy efficacy is limited due to chemoresistance, toxicity, and negative side effects. Overwhelming evidence supporting the small-molecule metabolites derived from breakdown of food or microbial sources confer an extensive array of host benefits, including chemo-preventive role in colon cancer. Our previous study indicated that the introduction of glyoxylate (Glx), an intermediate product of microbial or plant metabolism, exerts a cytotoxic effect in colon cancer cells. This study was designed to evaluate the effects of Glx on colon cancer with molecular insights. For this, we established an AOM/DSS-induced colitis associated colon cancer model in mice. Supplementation of Glx in vivo reduced colitis associated tumor growth and altered the metabolic characteristics of tumor tissue in mice without initiating any severe liver or renal toxicity. More specifically, intake of glyoxylate accumulated glycine in the colon tissue by elevation of alanine-glyoxylate transferase (AGXT) activity. Glycine accumulation increased intracellular Ca2+ concentration via glycine receptor activation and dysregulation of Ca2+ homeostasis lead to induction of apoptosis that resulted in arresting tumor growth. Interestingly, elevation of AGXT activity or Glx related specific metabolic pathway provides better survival in colon cancer patients. Collectively, our exclusive findings support the exploration of Glx either as a preventive molecule or its inclusion in the treatment regimens for colon cancer.

3.
Bioresour Technol ; 412: 131364, 2024 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-39209227

RESUMO

Succinate was found extensive applications in the food additives, pharmaceutical, and biopolymers industries. However, the succinate biosynthesis in E. coli required IPTG, lacked NADH, and produced high yields only under anaerobic conditions, unsuitable for cell growth. To overcome these limitations, the glyoxylate shunt and reductive TCA pathway were simultaneously enhanced to produce succinate in both aerobic and anaerobic conditions and achieve a high cell growth meanwhile. On this basis, NADH availability and sugars uptake were increased. Furthermore, an oxygen-dependent promoter was used to dynamically regulate the expression level of key genes of reductive TCA pathway to avoid the usage of IPTG. The final strain E. coli Mgls7-32 could produce succinate from corn stover hydrolysate without an inducer, achieving a titer of 72.8 g/L in 5 L bioreactor (1.2 mol/mol of total sugars). Those findings will aid in the industrial production of succinate.


Assuntos
Ciclo do Ácido Cítrico , Escherichia coli , Fermentação , Glioxilatos , Ácido Succínico , Zea mays , Ácido Succínico/metabolismo , Escherichia coli/metabolismo , Glioxilatos/metabolismo , Hidrólise , Oxirredução , Reatores Biológicos , Anaerobiose
4.
Plant J ; 119(4): 2033-2044, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38949911

RESUMO

Plant fungal parasites manipulate host metabolism to support their own survival. Among the many central metabolic pathways altered during infection, the glyoxylate cycle is frequently upregulated in both fungi and their host plants. Here, we examined the response of the glyoxylate cycle in bread wheat (Triticum aestivum) to infection by the obligate biotrophic fungal pathogen Puccinia striiformis f. sp. tritici (Pst). Gene expression analysis revealed that wheat genes encoding the two unique enzymes of the glyoxylate cycle, isocitrate lyase (TaICL) and malate synthase, diverged in their expression between susceptible and resistant Pst interactions. Focusing on TaICL, we determined that the TaICL B homoeolog is specifically upregulated during early stages of a successful Pst infection. Furthermore, disruption of the B homoeolog alone was sufficient to significantly perturb Pst disease progression. Indeed, Pst infection of the TaICL-B disruption mutant (TaICL-BY400*) was inhibited early during initial penetration, with the TaICL-BY400* line also accumulating high levels of malic acid, citric acid, and aconitic acid. Exogenous application of malic acid or aconitic acid also suppressed Pst infection, with trans-aconitic acid treatment having the most pronounced effect by decreasing fungal biomass 15-fold. Thus, enhanced TaICL-B expression during Pst infection may lower accumulation of malic acid and aconitic acid to promote Pst proliferation. As exogenous application of aconitic acid and malic acid has previously been shown to inhibit other critical pests and pathogens, we propose TaICL as a potential target for disruption in resistance breeding that could have wide-reaching protective benefits for wheat and beyond.


Assuntos
Glioxilatos , Isocitrato Liase , Malato Sintase , Doenças das Plantas , Puccinia , Triticum , Triticum/microbiologia , Triticum/genética , Triticum/metabolismo , Triticum/enzimologia , Isocitrato Liase/metabolismo , Isocitrato Liase/genética , Doenças das Plantas/microbiologia , Doenças das Plantas/imunologia , Glioxilatos/metabolismo , Malato Sintase/metabolismo , Malato Sintase/genética , Puccinia/fisiologia , Puccinia/patogenicidade , Regulação da Expressão Gênica de Plantas , Resistência à Doença/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo
5.
Metab Eng ; 85: 1-13, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38942196

RESUMO

Yarrowia lipolytica is an industrial yeast that can convert waste oil to value-added products. However, it is unclear how this yeast metabolizes lipid feedstocks, specifically triacylglycerol (TAG) substrates. This study used 13C-metabolic flux analysis (13C-MFA), genome-scale modeling, and transcriptomics analyses to investigate Y. lipolytica W29 growth with oleic acid, glycerol, and glucose. Transcriptomics data were used to guide 13C-MFA model construction and to validate the 13C-MFA results. The 13C-MFA data were then used to constrain a genome-scale model (GSM), which predicted Y. lipolytica fluxes, cofactor balance, and theoretical yields of terpene products. The three data sources provided new insights into cellular regulation during catabolism of glycerol and fatty acid components of TAG substrates, and how their consumption routes differ from glucose catabolism. We found that (1) over 80% of acetyl-CoA from oleic acid is processed through the glyoxylate shunt, a pathway that generates less CO2 compared to the TCA cycle, (2) the carnitine shuttle is a key regulator of the cytosolic acetyl-CoA pool in oleic acid and glycerol cultures, (3) the oxidative pentose phosphate pathway and mannitol cycle are key routes for NADPH generation, (4) the mannitol cycle and alternative oxidase activity help balance excess NADH generated from ß-oxidation of oleic acid, and (5) asymmetrical gene expressions and GSM simulations of enzyme usage suggest an increased metabolic burden for oleic acid catabolism.


Assuntos
Acetilcoenzima A , Triglicerídeos , Yarrowia , Yarrowia/metabolismo , Yarrowia/genética , Acetilcoenzima A/metabolismo , Acetilcoenzima A/genética , Triglicerídeos/metabolismo , Ácido Oleico/metabolismo , Glucose/metabolismo , Oxirredução , Modelos Biológicos
6.
Methods Mol Biol ; 2792: 41-49, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38861077

RESUMO

Glutamate:glyoxylate aminotransferase (GGAT; EC 2.6.1.4) and serine:glyoxylate aminotransferase activities (SGAT; EC 2.6.1.45) are central photorespiratory reactions within plant peroxisomes. Both enzymatic reactions convert glyoxylate, a product of glycolate oxidase, to glycine, a substrate of the mitochondrial glycine decarboxylase complex. The GGAT reaction uses glutamate as an amino group donor and also produces α-ketoglutarate, which is recycled to glutamate in plastids by ferredoxin-dependent glutamate synthase. Using serine, a product of mitochondrial serine hydroxymethyltransferase, as an amino group donor, the SGAT reaction also produces hydroxypyruvate, a substrate of hydroxypyruvate reductase. The activities of these photorespiratory aminotransferases can be measured using indirect, coupled, spectrophotometric assays, detailed herein.


Assuntos
Espectrofotometria , Transaminases , Transaminases/metabolismo , Espectrofotometria/métodos , Glioxilatos/metabolismo , Ácido Glutâmico/metabolismo , Ensaios Enzimáticos/métodos , Respiração Celular
7.
Biosci Biotechnol Biochem ; 88(9): 1069-1072, 2024 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-38871868

RESUMO

Gluconobacter oxydans succinic semialdehyde reductase (GoxSSAR) and Acetobacter aceti glyoxylate reductase (AacGR) represent a novel class in the ß-hydroxyacid dehydrogenases superfamily. Kinetic analyses revealed GoxSSAR's activity with both glyoxylate and succinic semialdehyde, while AacGR is glyoxylate specific. GoxSSAR K167A lost activity with succinic semialdehyde but retained some with glyoxylate, whereas AacGR K175A lost activity. These findings elucidate differences between these homologous enzymes.


Assuntos
Acetobacter , Oxirredutases do Álcool , Gluconobacter oxydans , Glioxilatos , Especificidade por Substrato , Gluconobacter oxydans/enzimologia , Gluconobacter oxydans/metabolismo , Acetobacter/enzimologia , Acetobacter/metabolismo , Oxirredutases do Álcool/metabolismo , Oxirredutases do Álcool/química , Cinética , Glioxilatos/metabolismo , Succinato-Semialdeído Desidrogenase/metabolismo , Succinato-Semialdeído Desidrogenase/química , Succinato-Semialdeído Desidrogenase/genética , Ácido gama-Aminobutírico/análogos & derivados
8.
Kidney Int Rep ; 9(5): 1387-1396, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38707801

RESUMO

Introduction: Primary hyperoxaluria (PH) is a rare genetic disorder of hepatic glyoxylate metabolism. Nedosiran is an RNA interference (RNAi) therapeutic that the US Food and Drug Administration has approved for treatment of PH1. PHYOX3 is a trial evaluating monthly nedosiran in patients with PH. Methods: In this PHYOX3 interim analysis, participants with PH1 who continued from a single-dose nedosiran trial (PHYOX1), with no previous kidney or liver transplantation, dialysis, or evidence of systemic oxalosis were eligible. The safety and efficacy of once-monthly nedosiran was assessed over 30 months. Results: Thirteen participants completed PHYOX1 and continued into PHYOX3. At baseline, the mean (SD) and median (range) age was 24.2 (6.6) years and 23.0 (14-39) years, respectively; 53.8% were female and 61.5% were White. Mean estimated glomerular filtration rate (eGFR) remained stable (62-84.2 mL/min per 1.73 m2) to month 30. Mean 24-hour urinary oxalate (Uox) excretion showed a sustained reduction from baseline of ≥60% at every visit (months 2-30). From month 2, at least 10 of 13 (76.9%) participants achieved normal (<0.46 mmol/24h; upper limit of assay-normal [ULN]) or near-normal (≥0.46 to <0.60 mmol/24h; ≥ULN to <1.3 × ULN) 24-hour Uox excretion. All participants experienced ≥1 adverse event (AE), mostly mild or moderate in severity (primarily, injection site events). Three serious, not treatment-related AEs were reported; there were no deaths or study discontinuations due to AEs. Conclusion: Nedosiran was well-tolerated in patients with PH1, and treatment resulted in a sustained, substantial reduction in Uox excretion for at least 30 months in this long-term study. No safety signals have been identified to date. The PHYOX3 study is ongoing.

9.
Adv Biol (Weinh) ; : e2400083, 2024 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-38717792

RESUMO

The regulation of complex energy metabolism is intricately linked to cellular energy demands. Caloric restriction (CR) plays a pivotal role in modulating the expression of genes associated with key metabolic pathways, including glycolysis, the tricarboxylic acid (TCA) cycle, and the glyoxylate cycle. In this study, the chronological lifespan (CLS) of 35 viable single-gene deletion mutants under both non-restricted and CR conditions, focusing on genes related to these metabolic pathways is evaluated. CR is found to increase CLS predominantly in mutants associated with the glycolysis and TCA cycle. However, this beneficial effect of CR is not observed in mutants of the glyoxylate cycle, particularly those lacking genes for critical enzymes like isocitrate lyase 1 (icl1Δ) and malate synthase 1 (mls1Δ). This analysis revealed an increase in isocitrate lyase activity, a key enzyme of the glyoxylate cycle, under CR, unlike the activity of isocitrate dehydrogenase, which remains unchanged and is specific to the TCA cycle. Interestingly, rapamycin, a compound known for extending lifespan, does not increase the activity of the glyoxylate cycle enzyme. This suggests that CR affects lifespan through a distinct metabolic mechanism.

10.
Genomics ; 116(3): 110846, 2024 05.
Artigo em Inglês | MEDLINE | ID: mdl-38642856

RESUMO

Period circadian regulator 3 (PER3) functions as a tumor suppressor in various cancers. However, the role of PER3 in multiple myeloma (MM) has not been reported yet. Through this study, we aimed to investigate the potential role of PER3 in MM and the underlying mechanisms. RT-qPCR and western blotting were used to determine the mRNA and protein expression levels of PER3. Glyoxylate reductase 1 homolog (GLYR1) was predicted to be a transcription factor of PER3. The binding sites of GLYR1 on the promoter region of PER3 were analyzed using UCSC and confirmed using luciferase and chromatin immunoprecipitation assays. Viability, apoptosis, and metathesis were determined using CCK-8, colony formation, TUNEL, and transwell assays. We found that PER3 expression decreased in MM. Low PER3 levels may predict poor survival rates; PER3 overexpression suppresses the viability and migration of MM cells and promotes apoptosis. Moreover, GLYR1 transcriptionally activates PER3, and the knockdown of PER3 alleviates the effects of GLYR1 and induces its malignant behavior in MM cells. To conclude, GLYR1 upregulates PER3 and suppresses the aggressive behavior of MM cells, suggesting that GLYR1/PER3 signaling may be a potential therapeutic target for MM.


Assuntos
Movimento Celular , Proliferação de Células , Mieloma Múltiplo , Proteínas Circadianas Period , Humanos , Mieloma Múltiplo/genética , Mieloma Múltiplo/metabolismo , Mieloma Múltiplo/patologia , Linhagem Celular Tumoral , Proteínas Circadianas Period/genética , Proteínas Circadianas Period/metabolismo , Oxirredutases do Álcool/metabolismo , Oxirredutases do Álcool/genética , Apoptose , Regulação Neoplásica da Expressão Gênica
11.
J Exp Bot ; 75(16): 4891-4903, 2024 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-38686677

RESUMO

During germination plants rely entirely on their seed storage compounds to provide energy and precursors for the synthesis of macromolecular structures until the seedling has emerged from the soil and photosynthesis can be established. Lupin seeds use proteins as their major storage compounds, accounting for up to 40% of the seed dry weight. Lupins are therefore a valuable complement to soy as a source of plant protein for human and animal nutrition. The aim of this study was to elucidate how storage protein metabolism is coordinated with other metabolic processes to meet the requirements of the growing seedling. In a quantitative approach, we analysed seedling growth, as well as alterations in biomass composition, the proteome, and metabolite profiles during germination and seedling establishment in Lupinus albus. The reallocation of nitrogen resources from seed storage proteins to functional seed proteins was mapped based on a manually curated functional protein annotation database. Although classified as a protein crop, Lupinus albus does not use amino acids as a primary substrate for energy metabolism during germination. However, fatty acid and amino acid metabolism may be integrated at the level of malate synthase to combine stored carbon from lipids and proteins into gluconeogenesis.


Assuntos
Aminoácidos , Germinação , Lupinus , Proteínas de Plantas , Proteoma , Plântula , Lupinus/metabolismo , Lupinus/crescimento & desenvolvimento , Aminoácidos/metabolismo , Proteoma/metabolismo , Plântula/metabolismo , Plântula/crescimento & desenvolvimento , Proteínas de Plantas/metabolismo , Sementes/metabolismo , Sementes/crescimento & desenvolvimento
12.
Microb Cell Fact ; 23(1): 77, 2024 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-38475794

RESUMO

BACKGROUND: Erythritol is a four-carbon polyol with an unclear role in metabolism of some unconventional yeasts. Its production has been linked to the osmotic stress response, but the mechanism of stress protection remains unclear. Additionally, erythritol can be used as a carbon source. In the yeast Yarrowia lipolytica, its assimilation is activated by the transcription factor Euf1. The study investigates whether this factor can link erythritol to other processes in the cell. RESULTS: The research was performed on two closely related strains of Y. lipolytica: MK1 and K1, where strain K1 has no functional Euf1. Cultures were carried out in erythritol-containing and erythritol-free media. Transcriptome analysis revealed the effect of Euf1 on the regulation of more than 150 genes. Some of these could be easily connected with different aspects of erythritol assimilation, such as: utilization pathway, a new potential isoform of transketolase, or polyol transporters. However, many of the upregulated genes have never been linked to metabolism of erythritol. The most prominent examples are the degradation pathway of branched-chain amino acids and the glyoxylate cycle. The high transcription of genes affected by Euf1 is still dependent on the erythritol concentration in the medium. Moreover, almost all up-regulated genes have an ATGCA motif in the promoter sequence. CONCLUSIONS: These findings may be particularly relevant given the increasing use of erythritol-induced promoters in genetic engineering of Y. lipolytica. Moreover, use of this yeast in biotechnological processes often takes place under osmotic stress conditions. Erythritol might be produce as a by-product, thus better understanding of its influence on cell metabolism could facilitate processes optimization.


Assuntos
Yarrowia , Yarrowia/metabolismo , Fatores de Transcrição/genética , Eritritol/metabolismo , Glicerol/metabolismo , Perfilação da Expressão Gênica , Carbono/metabolismo
13.
Arch Microbiol ; 206(3): 126, 2024 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-38411730

RESUMO

Glyoxylate shunt is an important pathway for microorganisms to survive under multiple stresses. One of its enzymes, malate synthase (encoded by aceB gene), has been widely speculated for its contribution to both the pathogenesis and virulence of various microorganisms. We have previously demonstrated that malate synthase (MS) is required for the growth of Salmonella Typhimurium (S. Typhimurium) under carbon starvation and survival under oxidative stress conditions. The aceB gene is encoded by the acetate operon in S. Typhimurium. We attempted to study the activity of acetate promoter under both the starvation and oxidative stress conditions in a heterologous system. The lac promoter of the pUC19 plasmid was substituted with the putative promoter sequence of the acetate operon of S. Typhimurium upstream to the lacZ gene and transformed the vector construct into E. coli NEBα cells. The transformed cells were subjected to the stress conditions mentioned above. We observed a fourfold increase in the ß-galactosidase activity in these cells resulting from the upregulation of the lacZ gene in the stationary phase of cell growth (nutrient deprived) as compared to the mid-log phase. Following exposure of stationary phase cells to hypochlorite-induced oxidative stress, we further observed a 1.6-fold increase in ß galactosidase activity. These data suggest the induction of promoter activity of the acetate operon under carbon starvation and oxidative stress conditions. Thus, these observations corroborate our previous findings regarding the upregulation of aceB expression under stressful environments.


Assuntos
Escherichia coli , Salmonella typhimurium , Salmonella typhimurium/genética , Malato Sintase , Óperon , Estresse Oxidativo/genética , Acetatos , Carbono , Nutrientes
14.
J Hazard Mater ; 466: 133573, 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38306834

RESUMO

Biosourced and biodegradable plastics offer a promising solution to reduce environmental impacts of plastics for specific applications. Here, we report a novel bacterium named Alteromonas plasticoclasticus MED1 isolated from the marine plastisphere that forms biofilms on foils of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). Experiments of degradation halo, plastic matrix weight loss, bacterial oxygen consumption and heterotrophic biosynthetic activity showed that the bacterial isolate MED1 is able to degrade PHBV and to use it as carbon and energy source. The likely entire metabolic pathway specifically expressed by this bacterium grown on PHBV matrices was shown by further genomic and transcriptomic analysis. In addition to a gene coding for a probable secreted depolymerase, a gene cluster was located that encodes characteristic enzymes involved in the complete depolymerization of PHBV, the transport of oligomers, and in the conversion of the monomers into intermediates of central carbon metabolism. The transcriptomic experiments showed the activation of the glyoxylate shunt during PHBV degradation, setting the isocitrate dehydrogenase activity as regulated branching point of the carbon flow entering the tricarboxylic acid cycle. Our study also shows the potential of exploring the natural plastisphere to discover new bacteria with promising metabolic capabilities.


Assuntos
Bactérias , Poliésteres , Bactérias/genética , Bactérias/metabolismo , Hidroxibutiratos , Biopolímeros , Carbono/metabolismo
15.
J Inherit Metab Dis ; 47(2): 280-288, 2024 03.
Artigo em Inglês | MEDLINE | ID: mdl-38200664

RESUMO

Glyoxylate is a key metabolite generated from various precursor substrates in different subcellular compartments including mitochondria, peroxisomes, and the cytosol. The fact that glyoxylate is a good substrate for the ubiquitously expressed enzyme lactate dehydrogenase (LDH) requires the presence of efficient glyoxylate detoxification systems to avoid the formation of oxalate. Furthermore, this detoxification needs to be compartment-specific since LDH is actively present in multiple subcellular compartments including peroxisomes, mitochondria, and the cytosol. Whereas the identity of these protection systems has been established for both peroxisomes and the cytosol as concluded from the deficiency of alanine glyoxylate aminotransferase (AGT) in primary hyperoxaluria type 1 (PH1) and glyoxylate reductase (GR) in PH2, the glyoxylate protection system in mitochondria has remained less well defined. In this manuscript, we show that the enzyme glyoxylate reductase has a bimodal distribution in human embryonic kidney (HEK293), hepatocellular carcinoma (HepG2), and cervical carcinoma (HeLa) cells and more importantly, in human liver, and is actively present in both the mitochondrial and cytosolic compartments. We conclude that the metabolism of glyoxylate in humans requires the complicated interaction between different subcellular compartments within the cell and discuss the implications for the different primary hyperoxalurias.


Assuntos
Oxirredutases do Álcool , Mitocôndrias Hepáticas , Transaminases , Humanos , Mitocôndrias Hepáticas/metabolismo , Células HEK293 , Oxalatos/metabolismo , Fígado/metabolismo , Glioxilatos/metabolismo
16.
J Exp Bot ; 75(3): 979-1003, 2024 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-37877811

RESUMO

High temperatures impair plant growth and reduce agricultural yields, but the underlying mechanisms remain elusive. The unicellular green alga Chlamydomonas reinhardtii is an excellent model to study heat responses in photosynthetic cells due to its fast growth rate, many similarities in cellular processes to land plants, simple and sequenced genome, and ample genetic and genomics resources. Chlamydomonas grows in light by photosynthesis and with externally supplied acetate as an organic carbon source. Understanding how organic carbon sources affect heat responses is important for the algal industry but remains understudied. We cultivated wild-type Chlamydomonas under highly controlled conditions in photobioreactors at 25 °C (control), 35 °C (moderate high temperature), or 40 °C (acute high temperature) with or without constant acetate supply for 1 or 4 day. Treatment at 35 °C increased algal growth with constant acetate supply but reduced algal growth without sufficient acetate. The overlooked and dynamic effects of 35 °C could be explained by induced acetate uptake and metabolism. Heat treatment at 40 °C for more than 2 day was lethal to algal cultures with or without constant acetate supply. Our findings provide insights to understand algal heat responses and help improve thermotolerance in photosynthetic cells.


Assuntos
Chlamydomonas reinhardtii , Chlamydomonas , Chlamydomonas reinhardtii/metabolismo , Temperatura , Carbono/metabolismo , Fotossíntese , Acetatos/metabolismo
17.
Eur J Med Chem ; 265: 116058, 2024 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-38128237

RESUMO

The significant challenge in confronting TB eradication is the discursive treatment that results in the disease reactivation, patient non compliance and drug resistance. The presently available drug regimen for TB largely targets the active bacilli and thus remains inadequate against the dormant or persistent subpopulation of Mtb that results in latent TB affecting a quarter of the global population. The crucial pathways that are particularly essential for the survival of dormant Mtb demand better apprehension. Novel drugs are needed to specifically address these persisters in order to enhance treatment effectiveness. Among such pathways, the glyoxylate bypass plays a critical role in the persistence and latent infection of Mtb, making it a promising target for drug development in recent years. In this review, we have compiled the attributes of bacterial subpopulations liable for latent TB and the pathways indispensable for their survival. Specifically, we delve into the glyoxylate shunt pathway and its key enzymes as potential drug targets.


Assuntos
Tuberculose Latente , Mycobacterium tuberculosis , Tuberculose , Humanos , Mycobacterium tuberculosis/metabolismo , Antituberculosos/farmacologia , Antituberculosos/uso terapêutico , Antituberculosos/metabolismo , Tuberculose Latente/tratamento farmacológico , Tuberculose/tratamento farmacológico , Tuberculose/microbiologia , Descoberta de Drogas , Glioxilatos/metabolismo , Glioxilatos/uso terapêutico
18.
FEMS Yeast Res ; 242024 01 09.
Artigo em Inglês | MEDLINE | ID: mdl-38130235

RESUMO

Most nucleus-encoded mitochondrial precursor proteins are synthesized in the cytosol and imported into mitochondria in a post-translational manner. In recent years, the quality control mechanisms of nonimported mitochondrial proteins have been intensively studied. In a previous study, we established that in budding yeast a mutant form of citrate synthase 1 (N∆Cit1) that lacks the N-terminal mitochondrial targeting sequence, and therefore mislocalizes to the cytosol is targeted for proteasomal degradation by the SCFUcc1 ubiquitin ligase complex. Here, we show that Hsp70 and Hsp40 chaperones (Ssa1 and Ydj1 in yeast, respectively) are required for N∆Cit1 degradation under heat stress conditions. In the absence of Hsp70 function, a portion of N∆Cit1-GFP formed insoluble aggregates and cytosolic foci. However, the extent of ubiquitination of N∆Cit1 was unaffected, implying that Hsp70/Hsp40 chaperones are involved in the postubiquitination step of N∆Cit1 degradation. Intriguingly, degradation of cytosolic/peroxisomal gluconeogenic citrate synthase (Cit2), an endogenous substrate for SCFUcc1-mediated proteasomal degradation, was not highly dependent on Hsp70 even under heat stress conditions. These results suggest that mitochondrial citrate synthase is thermally vulnerable in the cytosol, where Hsp70/Hsp40 chaperones are required to facilitate its degradation.


Assuntos
Proteínas de Saccharomyces cerevisiae , Citrato (si)-Sintase/genética , Citrato (si)-Sintase/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Adenosina Trifosfatases/metabolismo , Proteínas de Choque Térmico HSP70/genética , Chaperonas Moleculares/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Mitocôndrias/metabolismo , Resposta ao Choque Térmico
19.
Int J Mol Sci ; 24(20)2023 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-37894747

RESUMO

During the storage, processing, and digestion of flavonoid-rich foods and beverages, a condensation of flavonoids with toxic carbonyl compounds occurs. The effect of the resulting products on cells remains largely unknown. The aim of the present study was to evaluate the effects of quercetin, taxifolin, catechin, eriodictyol, hesperetin, naringenin, and a condensation product of taxifolin with glyoxylic acid on the oxidative burst of neutrophils. It was found that the flavonoids and the condensation product inhibited the total production of ROS. Flavonoids decreased both the intra and extracellular ROS production. The condensation product had no effect on intracellular ROS production but effectively inhibited the extracellular production of ROS. Thus, the condensation of flavonoids with toxic carbonyl compounds may lead to the formation of compounds exhibiting potent inhibitory effects on the oxidative burst of neutrophils. The data also suggest that, during these reactions, the influence of a fraction of flavonoids and their polyphenolic derivatives on cellular functions may change. On the whole, the results of the study provide a better understanding of the effects of polyphenols on human health. In addition, these results reveal the structure-activity relationship of these polyphenols and may be useful in a search for new therapeutic agents against diseases associated with oxidative stress.


Assuntos
Flavonoides , Quercetina , Humanos , Flavonoides/farmacologia , Quercetina/farmacologia , Espécies Reativas de Oxigênio/farmacologia , Explosão Respiratória , Neutrófilos , Polifenóis/farmacologia
20.
Int J Biol Macromol ; 253(Pt 8): 127674, 2023 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-37890751

RESUMO

A number of carboligases, which catalyze condensation of C1- and/or C2-aldehydes into multi-carbon products, have been reported. However, their catalytic activities and/or regioselectivities remained rather low. Thereby, this study has focused on engineering of C1 and C2 carboligases for the regioselective condensation of C1-formaldehyde into C4-erythrulose via C2-glycolaldehyde. The crystal structure of the glyoxylate carboligase from Escherichia coli (EcGCL) was elucidated in complex with glycolaldehyde. A structure-guided rationale generated several mutants, one of whose catalytic activity reached 15.6 M-1·s-1, almost 10 times greater than the wild-type enzyme. Another variant (i.e., EcGCL_R484M/N283Q/L478M/M488L/R284K) has shown significantly increased stability to the glycolaldehyde toxicity, enabling production of glycolaldehyde to 31 mM from 75 mM formaldehyde (conversion: 83 %). Besides, the E1 subunit of α-ketoglutarate dehydrogenase complex from Vibrio vulnificus (VvSucA) was engineered as a regiospecific C2 carboligase for condensation of glycolaldehyde into erythrulose. The combination of EcGCL_R484M/N283Q/L478M/M488L/R284K and VvSucA_K228L led to the cascade production of erythrulose to 8 mM from 90 mM formaldehyde via glycolaldehyde without byproduct formation. This study will contribute to valorization of C1 gases into industrially relevant multi-carbon products in an environment-friendly way.


Assuntos
Escherichia coli , Tiamina Pirofosfato , Escherichia coli/genética , Formaldeído , Carbono
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