-
The Journal of Biological Chemistry Nov 2023Sulfoquinovose (SQ, 6-deoxy-6-sulfoglucose) is a sulfosugar that is the anionic head group of plant, algal, and cyanobacterial sulfolipids: sulfoquinovosyl...
Sulfoquinovose (SQ, 6-deoxy-6-sulfoglucose) is a sulfosugar that is the anionic head group of plant, algal, and cyanobacterial sulfolipids: sulfoquinovosyl diacylglycerols. SQ is produced within photosynthetic tissues, forms a major terrestrial reservoir of biosulfur, and is an important species within the biogeochemical sulfur cycle. A major pathway for SQ breakdown is the sulfoglycolytic Embden-Meyerhof-Parnas pathway, which involves cleavage of the 6-carbon chain of the intermediate sulfofructose-1-phosphate (SFP) into dihydroxyacetone and sulfolactaldehyde, catalyzed by class I or II SFP aldolases. While the molecular basis of catalysis is understood for class I SFP aldolases, comparatively little is known about class II SFP aldolases. Here, we report the molecular architecture and biochemical basis of catalysis of two metal-dependent class II SFP aldolases from Hafnia paralvei and Yersinia aldovae. 3D X-ray structures of complexes with substrate SFP and product dihydroxyacetone phosphate reveal a dimer-of-dimers (tetrameric) assembly, the sulfonate-binding pocket, two metal-binding sites, and flexible loops that are implicated in catalysis. Both enzymes were metal-dependent and exhibited high K values for SFP, consistent with their role in a unidirectional nutrient acquisition pathway. Bioinformatic analysis identified a range of sulfoglycolytic Embden-Meyerhof-Parnas gene clusters containing class I/II SFP aldolases. The class I and II SFP aldolases have mututally exclusive occurrence within Actinobacteria and Firmicutes phyla, respectively, while both classes of enzyme occur within Proteobacteria. This work emphasizes the importance of SQ as a nutrient for diverse bacterial phyla and the different chemical strategies they use to harvest carbon from this sulfosugar.
Topics: Aldehyde-Lyases; Carbon; Fructose-Bisphosphate Aldolase; Metals; Phosphates
PubMed: 37838169
DOI: 10.1016/j.jbc.2023.105338 -
Food Chemistry: X Oct 2023The purpose of this study was to investigate the differences in meat quality between two local breeds of Tibetan sheep, the White Tibetan sheep and the Black Tibetan...
The purpose of this study was to investigate the differences in meat quality between two local breeds of Tibetan sheep, the White Tibetan sheep and the Black Tibetan sheep in Qinghai, and to search for metabolic mechanisms that produce meat quality differences by analyzing differential metabolites and key rumen microorganisms. The meat quality results showed that one breed, SG73, was superior to the other (WG). Further investigation identified differences in the composition of muscle metabolites and rumen microorganisms between the two Tibetan sheep breeds. It also regulates muscle tenderness, water retention, fat content and the composition and content of AA and FA through two major metabolic pathways, AA metabolism and carbohydrate metabolism. These findings could be beneficial for the development of breeding strategies for Tibetan sheep in Qinghai in the future.
PubMed: 37780244
DOI: 10.1016/j.fochx.2023.100843 -
Cell Stress & Chaperones Nov 2023Plants trigger endoplasmic reticulum (ER) pathways to survive stresses, but the assistance of ER in plant tolerance still needs to be explored. Thus, we selected...
Plants trigger endoplasmic reticulum (ER) pathways to survive stresses, but the assistance of ER in plant tolerance still needs to be explored. Thus, we selected sensitive and tolerant contrasting abiotic stress sorghum varieties to test if they present a degree of tolerance to ER stress. Accordingly, this work evaluated crescent concentrations of tunicamycin (TM µg mL): control (0), lower (0.5), mild (1.5), and higher (2.5) on the initial establishment of sorghum seedlings CSF18 and CSF20. ER stress promoted growth and metabolism reductions, mainly in CSF18, from mild to higher TM. The lowest TM increased SbBiP and SbPDI chaperones, as well as SbbZIP60, and SbbIRE1 gene expressions, but mild and higher TM decreased it. However, CSF20 exhibited higher levels of SbBiP and SbbIRE1 transcripts. It corroborated different metabolic profiles among all TM treatments in CSF18 shoots and similarities between profiles of mild and higher TM in CSF18 roots. Conversely, TM profiles of both shoots and roots of CSF20 overlapped, although it was not complete under low TM treatment. Furthermore, ER stress induced an increase of carbohydrates (dihydroxyacetone in shoots, and cellobiose, maltose, ribose, and sucrose in roots), and organic acids (pyruvic acid in shoots, and butyric and succinic acids in roots) in CSF20, which exhibited a higher degree of ER stress tolerance compared to CSF18 with the root being the most affected plant tissue. Thus, our study provides new insights that may help to understand sorghum tolerance and the ER disturbance as significant contributor for stress adaptation and tolerance engineering.
Topics: Tunicamycin; Sorghum; Molecular Chaperones; Endoplasmic Reticulum; Endoplasmic Reticulum Stress
PubMed: 37775652
DOI: 10.1007/s12192-023-01382-5 -
Scientific Reports Sep 2023Glucose metabolism and DNA repair are fundamental cellular processes frequently dysregulated in cancer. In this study, we define a direct role for the glycolytic...
Glucose metabolism and DNA repair are fundamental cellular processes frequently dysregulated in cancer. In this study, we define a direct role for the glycolytic Aldolase A (ALDOA) protein in DNA double-strand break (DSB) repair. ALDOA is a fructose biphosphate Aldolase that catalyses fructose-1,6-bisphosphate to glyceraldehyde 3-phosphate (G3P) and dihydroxyacetone phosphate (DHAP), during glycolysis. Here, we show that upon DNA damage induced by ionising radiation (IR), ALDOA translocates from the cytoplasm into the nucleus, where it partially co-localises with the DNA DSB marker γ-H2AX. DNA damage was shown to be elevated in ALDOA-depleted cells prior to IR and following IR the damage was repaired more slowly. Consistent with this, cells depleted of ALDOA exhibited decreased DNA DSB repair via non-homologous end-joining and homologous recombination. In support of the defective repair observed in its absence, ALDOA was found to associate with the major DSB repair effector kinases, DNA-dependent Protein Kinase (DNA-PK) and Ataxia Telangiectasia Mutated (ATM) and their autophosphorylation was decreased when ALDOA was depleted. Together, these data establish a role for an essential metabolic protein, ALDOA in DNA DSB repair and suggests that targeting ALDOA may enable the concurrent targeting of cancer metabolism and DNA repair to induce tumour cell death.
Topics: Humans; Fructose-Bisphosphate Aldolase; DNA-Activated Protein Kinase; Ataxia Telangiectasia; DNA Repair; Fructose; DNA; Ataxia Telangiectasia Mutated Proteins
PubMed: 37704669
DOI: 10.1038/s41598-023-41133-1 -
Chemical Research in Toxicology Sep 2023Aerosol formation and production yields from 11 carbonyls (carbonyl concentration per aerosol mass unit) were investigated (1) from a fourth-generation (4th gen)...
Carbonyls and Aerosol Mass Generation from Vaping Nicotine Salt Solutions Using Fourth- and Third-Generation E-Cigarette Devices: Effects of Coil Resistance, Coil Age, and Coil Metal Material.
Aerosol formation and production yields from 11 carbonyls (carbonyl concentration per aerosol mass unit) were investigated (1) from a fourth-generation (4th gen) e-cigarette device at different coil resistances and coil age (0-5000 puffs) using unflavored e-liquid with 2% benzoic acid nicotine salt, (2) between a sub-ohm third-generation (3rd gen) tank mod at 0.12 Ω and a 4th gen pod at 1.2 Ω using e-liquid with nicotine salt, together with nicotine yield, and (3) from 3rd gen coils of different metals (stainless steel, kanthal, nichrome) using e-liquid with freebase nicotine. Coil resistance had an inverse relationship with coil temperature, and coil temperature was directly proportional to aerosol mass formation. Trends in carbonyl yields depended on carbonyl formation mechanisms. Carbonyls produced primarily from thermal degradation chemistry (e.g., formaldehyde, acetaldehyde, acrolein, propionaldehyde) increased per aerosol mass with higher coil resistances, despite lower coil temperature. Carbonyls produced primarily from chemistry initiated by reactive oxygen species (ROS) (e.g., hydroxyacetone, dihydroxyacetone, methylglyoxal, glycolaldehyde, lactaldehyde) showed the opposite trend. Coil age did not alter coil temperature nor aerosol mass formation but had a significant effect on carbonyl formation. Thermal carbonyls were formed optimally at 500 puffs in our study and then declined to a baseline, whereas ROS-derived carbonyls showed a slow rise to a maximum trend with coil aging. The 3rd gen versus 4th gen device comparison mirrored the trends in coil resistance. Nicotine yields per aerosol mass were consistent between 3rd and 4th gen devices. Coil material did not significantly alter aerosol formation nor carbonyl yield when adjusted for wattage. This work shows that sub-ohm coils may not necessarily produce higher carbonyl yields even when they produce more aerosol mass. Furthermore, carbonyl formation is dynamic and not generalizable during the coil's lifetime. Finally, studies that compare data across different e-cigarette devices, coil age, and coil anatomy should account for the aerosol chemistry trends that depend on these parameters.
PubMed: 37698991
DOI: 10.1021/acs.chemrestox.3c00172 -
Metabolites Aug 2023Osteoarthritis (OA) is a common cause of lameness in sport horses with a significant economic impact. The prevention of OA is crucial since no effective treatment is...
Osteoarthritis (OA) is a common cause of lameness in sport horses with a significant economic impact. The prevention of OA is crucial since no effective treatment is available. This study aimed to apply untargeted metabolomic analysis to investigate the differences in synovial fluid (SF) composition between healthy and OA-affected joints in horses. SF collected from healthy (n.8) and OA (n.11) horses was analyzed using H-NMR analysis. Metabolomic analysis allowed 55 different metabolites to be identified and quantified in SF samples. Nineteen metabolites were found to be differently concentrated in OA compared to control horses. Synovial fluids from the OC group were found to be higher in 1,3-dihydroxyacetone but lower in tryptophan, phenylalanine, tyrosine, uridine, creatinine, creatine, glycine, choline, asparagine, glutamine, arginine, 3-hydroxybutyrate, valine, 2-hydroxyisovalerate, α-ketoisovaleric acid, 3-methyl-2-oxovalerate, 3-hydroxyisobutyrate, isoleucine, and methionine compared to the controls. A variety of SF metabolites significantly changed following joint disease, demonstrating the complex mechanism underlying osteoarthritis in horses and highlighting the value of applying the metabolomic approach in clinical research.
PubMed: 37623857
DOI: 10.3390/metabo13080913 -
BioRxiv : the Preprint Server For... Aug 2023All organisms utilize -adenosyl-l-methionine (SAM) as a key co-substrate for methylation of biological molecules, synthesis of polyamines, and radical SAM reactions....
All organisms utilize -adenosyl-l-methionine (SAM) as a key co-substrate for methylation of biological molecules, synthesis of polyamines, and radical SAM reactions. When these processes occur, 5'-deoxy-nucleosides are formed as byproducts such as -adenosyl-l-homocysteine (SAH), 5'-methylthioadenosine (MTA), and 5'-deoxyadenosine (5dAdo). One of the most prevalent pathways found in bacteria for the metabolism of MTA and 5dAdo is the DHAP shunt, which converts these compounds into dihydroxyacetone phosphate (DHAP) and 2-methylthioacetaldehyde or acetaldehyde, respectively. Previous work has shown that the DHAP shunt can enable methionine synthesis from MTA or serve as an MTA and 5dAdo detoxification pathway. Here we show that in Extraintestinal Pathogenic (ExPEC), the DHAP shunt serves none of these roles in any significant capacity, but rather physiologically functions as an assimilation pathway for use of MTA and 5dAdo as growth substrates. This is further supported by the observation that when MTA is the substrate for the ExPEC DHAP shunt, the sulfur components is not significantly recycled back to methionine, but rather accumulates as 2-methylthioethanol, which is slowly oxidized non-enzymatically under aerobic conditions. While the pathway is active both aerobically and anaerobically, it only supports aerobic ExPEC growth, suggesting that it primarily functions in oxygenic extraintestinal environments like blood and urine versus the predominantly anoxic gut. This reveals a heretofore overlooked role of the DHAP shunt in carbon assimilation and energy metabolism from ubiquitous SAM utilization byproducts and suggests a similar role may occur in other pathogenic and non-pathogenic bacteria with the DHAP shunt.
PubMed: 37609188
DOI: 10.1101/2023.08.10.552779 -
Nature Communications Jul 2023Neutrophils rely predominantly on glycolytic metabolism for their biological functions, including reactive oxygen species (ROS) production. Although pyruvate kinase M2...
Neutrophils rely predominantly on glycolytic metabolism for their biological functions, including reactive oxygen species (ROS) production. Although pyruvate kinase M2 (PKM2) is a glycolytic enzyme known to be involved in metabolic reprogramming and gene transcription in many immune cell types, its role in neutrophils remains poorly understood. Here, we report that PKM2 regulates ROS production and microbial killing by neutrophils. Zymosan-activated neutrophils showed increased cytoplasmic expression of PKM2. Pharmacological inhibition or genetic deficiency of PKM2 in neutrophils reduced ROS production and Staphylococcus aureus killing in vitro. In addition, this also resulted in phosphoenolpyruvate (PEP) accumulation and decreased dihydroxyacetone phosphate (DHAP) production, which is required for de novo synthesis of diacylglycerol (DAG) from glycolysis. In vivo, PKM2 deficiency in myeloid cells impaired the control of infection with Staphylococcus aureus. Our results fill the gap in the current knowledge of the importance of lower glycolysis for ROS production in neutrophils, highlighting the role of PKM2 in regulating the DHAP and DAG synthesis to promote ROS production in neutrophils.
Topics: Pyruvate Kinase; Reactive Oxygen Species; Neutrophils; Phosphorylation; Glycolysis
PubMed: 37460614
DOI: 10.1038/s41467-023-40021-6 -
Polymers May 2023Bacterial immobilization is regarded as an enabling technology to improve the stability and reusability of biocatalysts. Natural polymers are often used as...
Bacterial immobilization is regarded as an enabling technology to improve the stability and reusability of biocatalysts. Natural polymers are often used as immobilization matrices but present certain drawbacks, such as biocatalyst leakage and loss of physical integrity upon utilization in bioprocesses. Herein, we prepared a hybrid polymeric matrix that included silica nanoparticles for the unprecedented immobilization of the industrially relevant (Gfr). This biocatalyst can valorize glycerol, an abundant by-product of the biodiesel industry, into glyceric acid (GA) and dihydroxyacetone (DHA). Different concentrations of siliceous nanosized materials, such as biomimetic Si nanoparticles (SiNps) and montmorillonite (MT), were added to alginate. These hybrid materials were significantly more resistant by texture analysis and presented a more compact structure as seen by scanning electron microscopy. The preparation including 4% alginate with 4% SiNps proved to be the most resistant material, with a homogeneous distribution of the biocatalyst in the beads as seen by confocal microscopy using a fluorescent mutant of Gfr. It produced the highest amounts of GA and DHA and could be reused for up to eight consecutive 24 h reactions with no loss of physical integrity and negligible bacterial leakage. Overall, our results indicate a new approach to generating biocatalysts using hybrid biopolymer supports.
PubMed: 37299313
DOI: 10.3390/polym15112514 -
Investigative Ophthalmology & Visual... May 2023Plasmalogens (Plgs) are highly abundant lipids in the retina, and their deficiency leads to severe abnormalities during eye development. The first acylation step in the...
PURPOSE
Plasmalogens (Plgs) are highly abundant lipids in the retina, and their deficiency leads to severe abnormalities during eye development. The first acylation step in the synthesis of Plgs is catalyzed by the enzyme glyceronephosphate O-acyltransferase (GNPAT), which is also known as dihydroxyacetone phosphate-acyltransferase (EC 2.3.1.42). GNPAT deficiency produces rhizomelic chondrodysplasia punctata type 2, a genetic disorder associated with developmental ocular defects. Despite the relevance of retinal Plgs, our knowledge of the mechanisms that regulate their synthesis, and the role of GNPAT during eye development is limited.
METHODS
Using the Xenopus laevis model organism, we characterized by in situ hybridization the expression pattern of gnpat and compared it to glycerol 3-phosphate acyltransferase mitochondrial (gpam or gpat1) during eye neurogenesis, lamination, and morphogenesis. The Xenopus Gnpat was biochemically characterized in a heterologous expression system in yeast.
RESULTS
During development, gnpat is expressed in proliferative cells of the retina and lens, and post-embryogenesis in proliferative cells of the ciliary marginal zone and lens epithelium. In contrast, gpam expression is mainly restricted to photoreceptors. Xenopus Gnpat expressed in yeast is present in both soluble and membrane fractions, but only the membrane-bound enzyme displays activity. The amino terminal of Gnpat, conserved in humans, shows lipid binding capacity that is enhanced by phosphatidic acid.
CONCLUSIONS
Enzymes involved in the Plgs and glycerophospholipid biosynthetic pathways are differentially expressed during eye morphogenesis. The gnpat expression pattern and the molecular determinants regulating Gnpat activity advance our knowledge of this enzyme, contributing to our understanding of the retinal pathophysiology associated with GNPAT deficiency.
Topics: Animals; Humans; Acyltransferases; Plasmalogens; Saccharomyces cerevisiae; Xenopus laevis; Xenopus Proteins
PubMed: 37204785
DOI: 10.1167/iovs.64.5.17