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American Journal of Physiology.... Jun 2018Mitochondrial bioenergetic contributions to sex differences in human skeletal muscle metabolism remain poorly defined. The primary aim of this study was to determine...
Mitochondrial bioenergetic contributions to sex differences in human skeletal muscle metabolism remain poorly defined. The primary aim of this study was to determine whether mitochondrial respiratory kinetics differed between healthy young men and women in permeabilized skeletal muscle fibers. While men and women displayed similar ( P > 0.05) maximal respiration rates and abundance of mitochondrial/adenosine diphosphate (ADP) transport proteins, women had lower ( P < 0.05) mitochondrial ADP sensitivity (+30% apparent K) and absolute respiration rates at a physiologically relevant ADP concentration (100 μM). Moreover, although men and women exhibited similar carnitine palmitoyl transferase-I protein content- and palmitoyl-CoA-supported respiration, women displayed greater sensitivity to malonyl-CoA-mediated respiratory inhibition. These data establish baseline sex differences in mitochondrial bioenergetics and provide the foundation for studying mitochondrial function within the context of metabolic perturbations and diseases that affect men and women differently.
Topics: Absorptiometry, Photon; Adenosine Diphosphate; Adiposity; Aerobiosis; Energy Metabolism; Female; Humans; Kinetics; Male; Mitochondria, Muscle; Muscle, Skeletal; Oxygen Consumption; Sex Characteristics; Young Adult
PubMed: 29513564
DOI: 10.1152/ajpregu.00025.2018 -
Molecules (Basel, Switzerland) Nov 2021Lactate and isoprene are two common monomers for the industrial production of polyesters and synthetic rubbers. The present study tested the co-production of D-lactate...
Lactate and isoprene are two common monomers for the industrial production of polyesters and synthetic rubbers. The present study tested the co-production of D-lactate and isoprene by engineered in microaerobic conditions. The deletion of alcohol dehydrogenase () and acetate kinase () genes, along with the supplementation with betaine, improved the co-production of lactate and isoprene from the substrates of glucose and mevalonate. In fed-batch studies, microaerobic fermentation significantly improved the isoprene concentration in fermentation outlet gas (average 0.021 g/L), compared with fermentation under aerobic conditions (average 0.0009 g/L). The final production of D-lactate and isoprene can reach 44.0 g/L and 3.2 g/L, respectively, through fed-batch microaerobic fermentation. Our study demonstrated a dual-phase production strategy in the co-production of isoprene (gas phase) and lactate (liquid phase). The increased concentration of gas-phase isoprene could benefit the downstream process and decrease the production cost to collect and purify the bio-isoprene from the fermentation outlet gas. The proposed microaerobic process can potentially be applied in the production of other volatile bioproducts to benefit the downstream purification process.
Topics: Aerobiosis; Butadienes; Escherichia coli; Fermentation; Hemiterpenes; Lactic Acid; Metabolic Engineering; Mevalonic Acid
PubMed: 34885764
DOI: 10.3390/molecules26237173 -
Medecine Sciences : M/S Apr 2018Energy is the major determinant of neuronal viability. We focus our synthesis on the hypothesis of the development of aerobic glycolysis by the stimulation of the... (Review)
Review
Energy is the major determinant of neuronal viability. We focus our synthesis on the hypothesis of the development of aerobic glycolysis by the stimulation of the canonical WNT/β-catenin pathway in amyotrophic lateral sclerosis (ALS). The stimulation of the canonical WNT/β-catenin pathway induces the activation of aerobic glycolysis, also called Warburg effect, via the stimulation of glycolytic enzymes such as Glut (glucose transporter), PKM2 (pyruvate kinase M2), PDK1 (pyruvate dehydrogenase kinase 1), LDH-A (lactate dehydrogenase A) and MCT-1 (monocarboxylate transporter 1). The aerobic glycolysis consists to a supply of a large part of glucose into lactate regardless of oxygen. Aerobic glycolysis is less efficient in terms of ATP production than oxidative phosphorylation due to the shunt of the TCA cycle. Dysregulation of cellular energy metabolism promotes cell death and participates to the progression of ALS. Controlling the expression of the canonical WNT/β-catenin signaling pathway is an attractive strategy to regulate aerobic glycolysis initiation and the progression of ALS.
Topics: Aerobiosis; Amyotrophic Lateral Sclerosis; Animals; Glycolysis; Humans; Wnt Signaling Pathway; beta Catenin
PubMed: 29658475
DOI: 10.1051/medsci/20183404013 -
Journal of Animal Science Jul 2021We evaluated the effects of different types of additives on the fermentation and aerobic stability of alfalfa (Medicago sativa) ensiled at 2 dry matters (DM). Alfalfa...
Effect of microbial and chemical additives on the fermentation and aerobic stability of alfalfa silage ensiled at 2 dry matters and subjected to air stress during storage.
We evaluated the effects of different types of additives on the fermentation and aerobic stability of alfalfa (Medicago sativa) ensiled at 2 dry matters (DM). Alfalfa was untreated (CTRL) or treated with sodium benzoate, potassium sorbate, and sodium nitrite (SFE), or microbial inoculants (Lactobacillus plantarum MTD1 [LP] or L. buchneri 40788 and Pediococcus pentocaseus 12455 [LBPP]) at a moderate (38%) and high (46%) DM using a completely randomized design with a 2 × 4 factorial arrangement of treatments. High DM silage was higher (P < 0.01) in pH, had less lactic and acetic acid (P < 0.01) and had more yeasts (P < 0.05) and molds (P < 0.01) than moderate DM silage. Recovery of DM declined (P < 0.01) for CTRL and LP treated silages with increasing DM but was not different between LBPP and SFE treatments. Compared to CTRL, LBPP had a lower (P < 0.01) DM recovery at the moderate DM, but SFE had the greatest (P < 0.01) recovery of all treatments at the high DM. Treatment with LBPP increased (P < 0.05) the concentrations of acetic acid and 1,2 propanediol (PD) compared with other treatments (P < 0.01). Numerically, fewer yeasts were found in additive treated silages compared with CTRL, but they were statistically (P < 0.01) lower only when treated with SFE. Treatment with LP resulted in a small improvement in aerobic stability at the moderate but not high DM. In contrast, treatment with SFE and LBPP markedly improved (P < 0.01) the aerobic stability of alfalfa silage at both DM. Whereas SFE and LBPP were similar in their improvements in aerobic stability at the DM, LBPP was better (P < 0.01) than SFE at the high DM. A higher (P < 0.01) concentration of acetic acid in LBPP compared with other treatments was most likely responsible for better stability. This study showed that LBPP and SFE resulted in increases in the aerobic stability of alfalfa silage and it is the first study showing SFE, can markedly improve the aerobic stability of alfalfa silage.
Topics: Aerobiosis; Animals; Fermentation; Lactobacillus; Medicago sativa; Silage; Zea mays
PubMed: 34051076
DOI: 10.1093/jas/skab174 -
Scientific Reports Mar 2020This study aimed to investigate the effects of microbial inoculants (L) and molasses (M) on the bacterial and fungal microbiomes of barley silage after the aerobic...
This study aimed to investigate the effects of microbial inoculants (L) and molasses (M) on the bacterial and fungal microbiomes of barley silage after the aerobic stage. The addition of molasses and microbial inoculants improved the aerobic stability of barley silage. The ML silage, which had a low pH value and high lactic and acetic acid contents, remained aerobically stable for more than 216 h. The ML silage exhibited low bacterial and high fungal diversities. Microbial inoculants and molasses enriched the abundance of Lactobacillus in silage after aerobic exposure. The enrichment of L. buchneri was significant in ML silage at days 5 and 7 during the aerobic stage. The abundance of harmful microorganisms, such as aerobic bacterial including Acinetobacter, Providencia, Bacillus, and yeasts including Issatchenkia, Candida, and Kazachstania, were suppressed in ML silage. M and L had an impact on bacterial and fungal microbes, resulting in the improvement of fermentation quality and reduction of aerobic spoilage in barley silage.
Topics: Aerobiosis; Agricultural Inoculants; Bacteria; Fermentation; High-Throughput Nucleotide Sequencing; Hordeum; Lactobacillales; Lactobacillus; Microbiota; Molasses; Mycobiome; Silage
PubMed: 32210338
DOI: 10.1038/s41598-020-62290-7 -
The ISME Journal Jan 2020Mechanistic description of the transition from aerobic to anaerobic metabolism is necessary for diagnostic and predictive modeling of fixed nitrogen loss in anoxic...
Mechanistic description of the transition from aerobic to anaerobic metabolism is necessary for diagnostic and predictive modeling of fixed nitrogen loss in anoxic marine zones (AMZs). In a metabolic model where diverse oxygen- and nitrogen-cycling microbial metabolisms are described by underlying redox chemical reactions, we predict a transition from strictly aerobic to predominantly anaerobic regimes as the outcome of ecological interactions along an oxygen gradient, obviating the need for prescribed critical oxygen concentrations. Competing aerobic and anaerobic metabolisms can coexist in anoxic conditions whether these metabolisms represent obligate or facultative populations. In the coexistence regime, relative rates of aerobic and anaerobic activity are determined by the ratio of oxygen to electron donor supply. The model simulates key characteristics of AMZs, such as the accumulation of nitrite and the sustainability of anammox at higher oxygen concentrations than denitrification, and articulates how microbial biomass concentrations relate to associated water column transformation rates as a function of redox stoichiometry and energetics. Incorporating the metabolic model into an idealized two-dimensional ocean circulation results in a simulated AMZ, in which a secondary chlorophyll maximum emerges from oxygen-limited grazing, and where vertical mixing and dispersal in the oxycline also contribute to metabolic co-occurrence. The modeling approach is mechanistic yet computationally economical and suitable for global change applications.
Topics: Aerobiosis; Anaerobiosis; Chlorophyll; Denitrification; Models, Biological; Nitrites; Nitrogen; Oxygen; Seawater
PubMed: 31624350
DOI: 10.1038/s41396-019-0523-8 -
The Science of the Total Environment Jul 2022Most bacteria live in microbial assemblages like biofilms and granules, and each layer of these assemblages provides a niche for certain bacteria with specific metabolic...
Most bacteria live in microbial assemblages like biofilms and granules, and each layer of these assemblages provides a niche for certain bacteria with specific metabolic functions. In this study, a gentle (non-destructive) extraction approach based on a cation exchange resin and defined shear was employed to gradually disintegrate biomass and collect single layers of aerobic granules from a full-scale municipal wastewater treatment plant. The microbial community composition of granule layers was characterized using next-generation sequencing (NGS) targeting the 16S rRNA gene, and protein composition was investigated using metaproteomics. The chemical composition of eroded layers was explored using Fourier Transformed Infrared Spectroscopy. On the surface of the granules, the microbial structure (flocculation-supporting Nannocystis sp.) as well as composition of extracellular polymers (extracellular DNA) and proteome (chaperonins and binding proteins) favored microbial aggregation. Extracellular polymeric substances in the granules were composed of mostly proteins and EPS-producers, such as Tetrasphaera sp. and Zoogloea sp., were evenly distributed throughout the granule structure. The interior of the granules harbored several denitrifiers (e.g., Thauera sp.), phosphate-accumulating denitrifiers (Candidatus Accumulibacter, Dechloromonas sp.) and nitrifiers (Candidatus Nitrotoga). Proteins associated with glycolytic activity were identified in the outer and middle granule layers, and proteins associated with phosphorus conversions, in the deeper layers. In conclusion, the use of an existing cation-exchange resin for gradual biomass disintegration, combined with NGS and metaproteomic analysis was demonstrated as a promising approach for simultaneously investigating the identity and functions of microbes in multilayered biofilm structures.
Topics: Aerobiosis; Bioreactors; Microbiota; Proteins; RNA, Ribosomal, 16S; Sewage; Waste Disposal, Fluid
PubMed: 35276168
DOI: 10.1016/j.scitotenv.2022.154253 -
Journal of Animal Science Aug 2021We evaluated the effects of applying a combination inoculant to four corn hybrids harvested at high moisture on their nutritive value and microbial populations. The...
A combination of Lactobacillus buchneri and Pediococcus pentosaceus extended the aerobic stability of conventional and brown midrib mutants-corn hybrids ensiled at low dry matter concentrations by causing a major shift in their bacterial and fungal community.
We evaluated the effects of applying a combination inoculant to four corn hybrids harvested at high moisture on their nutritive value and microbial populations. The treatment design was the factorial combination of corn hybrids ensiled with (INO) and without (CON) inoculant. The hybrids were TMF2R737 (MCN), F2F817 (MBR), P2089YHR (PCN), and PI144XR (PBR), ensiled at dry matter (DM) concentrations of 30.5%, 26.3%, 31.1%, and 31.5%, respectively; MBR and PBR were brown midrib mutants (BMR). The inoculant contained Lactobacillus buchneri and Pediococcus pentosaceus (4 × 105 and 1 × 105 cfu/g of fresh corn). The experiment had a complete randomized design with treatments replicated six times. Corn was treated or not with inoculant, packed into 7.6 L bucket silos, and stored for 100 d. At d 0, the relative abundance (RA, %) of Enterobacteriaceae was lower in PBR vs. the other hybrids [51.3 vs. x¯ = (average of) 58.4] and in the case of fungi, incertae sedis (i.s.) Tremellales and Mucoraceae were more and less abundant, respectively, in conventional hybrids vs. BMRs (x¯= 25.8 vs. x¯ = 13.9 and x¯ = 3.64 vs. x¯ = 7.52; P < 0.04). After ensiling, INO had higher LAB (9.3 vs. 7.1 log cfu/g of fresh corn) and acetic acid (3.44% vs. 1.32% of DM) and lower yeast (3.1 vs. 4.6) and molds (1.5 vs. 3.0), and also extended the aerobic stability (582 vs. 111 h) but decreased DM recovery (95.6% vs. 97.4%) vs. CON (P < 0.02). Inoculation reduced bacterial phylogenetic diversity (6.75 vs. 14.4) but increased fungal observed taxonomical units (46 vs. 20) vs. CON (P < 0.01). Also, a higher relative abundance (RA) for Lactobacillaceae (99.2% vs. 75.7%) and lower for Enterobacteriaceae (0.28 vs. 9.93) was observed due to inoculation (P < 0.001). For fungi, INO had a lower RA compared to CON for Monascaceae (12.6 vs. 44.7) and increased i.s. Tremellales (8.0 vs. 1.2) and i.s. Saccharomycetales (6.4% vs. 0.3%; P < 0.006). Inoculation changed the diverse bacterial community found in the phyllosphere across hybrids to a taxonomically uneven one dominated by Lactobacillaceae. In the case of fungi, INO application increased the fungal diversity at d 100 mainly by reducing the dominance of Monascaceae vs. CON. In conclusion, the INO treatment overwhelmed the disparate microbial populations found across BMR and conventional hybrids ensiled at low DM concentrations and ensured a significant concentration of acetic acid that modified fungal populations and in turn extended the aerobic stability of all hybrids.
Topics: Aerobiosis; Animals; Fermentation; Lactobacillus; Mycobiome; Pediococcus pentosaceus; Phylogeny; Saccharomyces cerevisiae; Silage; Zea mays
PubMed: 33959750
DOI: 10.1093/jas/skab141 -
Respiratory Medicine Dec 2018Left ventricular diastolic dysfunction (LVDD) is highly prevalent in COPD and conflicting results have emerged regarding the consequences on exercise capacity in the...
BACKGROUND
Left ventricular diastolic dysfunction (LVDD) is highly prevalent in COPD and conflicting results have emerged regarding the consequences on exercise capacity in the 6MWT. We sought to examine the ventilatory efficiency and variability metrics as the primary endpoint and aerobic capacity (V'O) as the secondary endpoint.
METHODS
Forty subjects were included and submitted to comprehensive lung function tests, detailed pulsed-Doppler echocardiography, and cardiopulmonary exercise testing. Four subjects were excluded due to concomitant cardiac disease and two owing to COPD exacerbation.
RESULTS
Seventeen COPD/LVDD+ and seventeen COPD/LVDD-individuals were closely matched for baseline characteristics. Throughout the exercise, there was no difference between-groups for primary (V'/V'COslope and V'/V'COnadir, p > 0.05 for both) or secondary endpoints (V'O%pred, p > 0.05). Ventilatory variability remained unchanged. However, after very well age- and sex-matched subgroup analysis, five-moderate and three-mild COPD/LVDD + subjects with elevated left ventricular filling pressure (E/e'>13, n = 8), presented a downward-shifted V'/V'COslope (25.7 ± 5.1 vs 33.4 ± 7.1, p = 0.031) and V'/V'COnadir reduction (29.7 ± 3.9 vs 36.3 ± 7.2, p = 0.042) besides significantly better V'O%pred (92.1 ± 21.6% vs 75.8 ± 13.1%, p = 0.045) compared to 8 COPD/LVDD-controls. Ventilatory variability remained once again unchanged.
CONCLUSIONS
COPD/LVDD overlap is not associated with worse exercise tolerance and/or wasted ventilation in excess compared to controls, even when suspected for elevated left ventricular filling pressure. Further studies are warranted to study specifically if augmented pulmonary blood transit time can allow better gas-exchange, thus preserving exercise capacity under specific conditions in COPD patients without heart failure.
Topics: Aerobiosis; Aged; Exercise Tolerance; Female; Humans; Lung; Male; Middle Aged; Pulmonary Disease, Chronic Obstructive; Pulmonary Gas Exchange; Respiration; Respiratory Function Tests; Ventricular Dysfunction, Left
PubMed: 30509698
DOI: 10.1016/j.rmed.2018.10.014 -
Proceedings of the National Academy of... Dec 2021Aerobic fermentation, also referred to as the Crabtree effect in yeast, is a well-studied phenomenon that allows many eukaryal cells to attain higher growth rates at...
Aerobic fermentation, also referred to as the Crabtree effect in yeast, is a well-studied phenomenon that allows many eukaryal cells to attain higher growth rates at high glucose availability. Not all yeasts exhibit the Crabtree effect, and it is not known why Crabtree-negative yeasts can grow at rates comparable to Crabtree-positive yeasts. Here, we quantitatively compared two Crabtree-positive yeasts, and , and two Crabtree-negative yeasts, and , cultivated under glucose excess conditions. Combining physiological and proteome quantification with genome-scale metabolic modeling, we found that the two groups differ in energy metabolism and translation efficiency. In Crabtree-positive yeasts, the central carbon metabolism flux and proteome allocation favor a glucose utilization strategy minimizing proteome cost as proteins translation parameters, including ribosomal content and/or efficiency, are lower. Crabtree-negative yeasts, however, use a strategy of maximizing ATP yield, accompanied by higher protein translation parameters. Our analyses provide insight into the underlying reasons for the Crabtree effect, demonstrating a coupling to adaptations in both metabolism and protein translation.
Topics: Aerobiosis; Fermentation; Fungal Proteins; Gene Expression Regulation, Fungal; Glucose; Mitochondrial Proton-Translocating ATPases; Proteome; Species Specificity; Yeasts
PubMed: 34903663
DOI: 10.1073/pnas.2112836118