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The Science of the Total Environment May 2024In situ aerobic cometabolism of groundwater contaminants has been demonstrated to be a valuable bioremediation technology to treat many legacy and emerging contaminants... (Review)
Review
In situ aerobic cometabolism of groundwater contaminants has been demonstrated to be a valuable bioremediation technology to treat many legacy and emerging contaminants in dilute plumes. Several well-designed and documented field studies have shown that this technology can concurrently treat multiple contaminants and reach very low cleanup goals. Fundamentally different from metabolism-based biodegradation of contaminants, microorganisms that cometabolically degrade contaminants do not obtain sufficient carbon and energy from the degradation process to support their growth and require an exogenous growth supporting primary substrate. Successful applications of aerobic cometabolic treatment therefore require special considerations beyond conventional in situ bioremediation, such as competitive inhibition between growth-supporting primary substrate(s) and contaminant non-growth substrates, toxic effects resulting from contaminant degradation, and differences in microbial population dynamics exhibited by biostimulated indigenous consortia versus bioaugmentation cultures. This article first provides a general review of microbiological factors that are likely to affect the rate of aerobic cometabolic biodegradation. We subsequently review fourteen well documented field-scale aerobic cometabolic bioremediation studies and summarize the underlying microbiological factors that may affect the performance observed in these field studies. The combination of microbiological and engineering principles gained from field testing leads to insights and recommendations on planning, design, and operation of an in situ aerobic cometabolic treatment system. With a vision of more aerobic cometabolic treatments being considered to tackle large, dilute plumes, we present several novel topics and future research directions that can potentially enhance technology development and foster success in implementing this technology for environmental restoration.
Topics: Biodegradation, Environmental; Aerobiosis; Groundwater; Water Pollutants, Chemical
PubMed: 38485017
DOI: 10.1016/j.scitotenv.2024.171667 -
PloS One 2017Physical exercise may affect levels of blood-based biomarkers. However, exercise status is seldom considered in the interpretation of laboratory results. This study...
OBJECTIVES
Physical exercise may affect levels of blood-based biomarkers. However, exercise status is seldom considered in the interpretation of laboratory results. This study reports the associations between habitual exercise participation and clinical laboratory test results.
METHODS
The effects of days per week of aerobic and strength exercise participation on laboratory test results for 26 biomarkers in young adults aged 18 to 34 years (n = 80,111) were evaluated using percentile distribution analyses and multivariate regression.
RESULTS
In both men and women, more days per week of either aerobic or strength exercise were significantly associated with lower levels of glucose, hemoglobin A1c, LDL cholesterol, total cholesterol, triglycerides, estimated glomerular filtration rate, globulin, and C-reactive protein, and significantly higher levels of HDL cholesterol, creatinine, iron, and percent saturation (all p < .05). Type of exercise or gender influenced the observed relationships with exercise frequency for total cholesterol, aspartate aminotransferase, gamma-glutamyl transferase, alkaline phosphatase, uric acid, bilirubin, and iron binding capacity.
CONCLUSIONS
Physical exercise shifted the distribution of results into the direction suggestive of better health. Reported relationships may help clinicians and patients to better understand and interpret laboratory results in athletic populations and possibly re-evaluate interpretation of reference intervals for physically active populations.
Topics: Adolescent; Adult; Aerobiosis; Female; Humans; Male; Resistance Training; Young Adult
PubMed: 29059178
DOI: 10.1371/journal.pone.0180840 -
Journal of Hazardous Materials Feb 2021Saline wastewater is commonly encountered in various industries, posing challenges to biological treatments. The application of seawater as a seed source provides a...
Saline wastewater is commonly encountered in various industries, posing challenges to biological treatments. The application of seawater as a seed source provides a media of diverse halophilic organisms for rapid startup. However, effects of transitioning from a mixed salt source to monovalent salt solutions prevalent in industry remains unexplored. Hence, seed sludge was cultivated using seawater and later granulated under a mixed-salt synthetic medium comprising a mixture of NaCl, KCl and NaSO at a combined concentration of 0.8 M (0.27 M each). The stable, acclimated granules were then tested against single salt media of 0.8 M NaCl, KCl, or NaSO. Shift to single salt media resulted in granule disaggregation, poor settling, sludge washout and development of fluffy or slimy flocs. Changes in exopolysaccharides composition after the single salt shift was the predominant reason for the large changes in sludge morphology. The impacts of KCl and NaSO were more significant than the shift to NaCl. The resulting impacts also had a major influence on the treatment performance. A complex mechanism involving monovalent cation stimulation of proteins; ionic strength impacts on exopolysaccharides and morphology; solution density influence on sludge density and settling; and tonicity impacts on cell viability and treatment is described.
Topics: Aerobiosis; Bioreactors; Cations, Monovalent; Salts; Seawater; Sewage; Waste Disposal, Fluid
PubMed: 32846259
DOI: 10.1016/j.jhazmat.2020.123646 -
Environmental Microbiology Oct 2017Campylobacter jejuni, the most frequent cause of food-borne bacterial gastroenteritis worldwide, is a microaerophile that has to survive high environmental oxygen...
Transcriptome and proteome dynamics in chemostat culture reveal how Campylobacter jejuni modulates metabolism, stress responses and virulence factors upon changes in oxygen availability.
Campylobacter jejuni, the most frequent cause of food-borne bacterial gastroenteritis worldwide, is a microaerophile that has to survive high environmental oxygen tensions, adapt to oxygen limitation in the intestine and resist host oxidative attack. Here, oxygen-dependent changes in C. jejuni physiology were studied at constant growth rate using carbon (serine)-limited continuous chemostat cultures. We show that a perceived aerobiosis scale can be calibrated by the acetate excretion flux, which becomes zero when metabolism is fully aerobic (100% aerobiosis). Transcriptome changes in a downshift experiment from 150% to 40% aerobiosis revealed many novel oxygen-regulated genes and highlighted re-modelling of the electron transport chains. A label-free proteomic analysis showed that at 40% aerobiosis, many proteins involved in host colonisation (e.g., PorA, CadF, FlpA, CjkT) became more abundant. PorA abundance increased steeply below 100% aerobiosis. In contrast, several citric-acid cycle enzymes, the peptide transporter CstA, PEB1 aspartate/glutamate transporter, LutABC lactate dehydrogenase and PutA proline dehydrogenase became more abundant with increasing aerobiosis. We also observed a co-ordinated response of oxidative stress protection enzymes and Fe-S cluster biogenesis proteins above 100% aerobiosis. Our approaches reveal key virulence factors that respond to restricted oxygen availability and specific transporters and catabolic pathways activated with increasing aerobiosis.
Topics: Aerobiosis; Campylobacter Infections; Campylobacter jejuni; Humans; Oxidation-Reduction; Oxidative Stress; Oxygen; Proteome; Proteomics; Transcriptome; Virulence Factors
PubMed: 28892295
DOI: 10.1111/1462-2920.13930 -
Sheng Wu Gong Cheng Xue Bao = Chinese... Oct 2021Biological denitrification is the most widely used technology for nitrate removal in wastewater treatment. Conventional denitrification requires long hydraulic retention...
Biological denitrification is the most widely used technology for nitrate removal in wastewater treatment. Conventional denitrification requires long hydraulic retention time, and the nitrate removal efficiency in winter is low due to the low temperature. Therefore, it is expected to develop new approaches to enhance the denitrification process. In this paper, the effect of adding different concentrations of Fe₃O₄ nanoparticles on the denitrification catalyzed by Pseudomonas stutzeri was investigated. The maximum specific degradation rate of nitrate nitrogen improved from 18.0 h⁻¹ to 23.7 h⁻¹ when the concentration of Fe₃O₄ increased from 0 mg/L to 4 000 mg/L. Total proteins and intracellular iron content also increased along with increasing the concentration of Fe₃O₄. RT-qPCR and label-free proteomics analyses showed that the relative expression level of denitrifying genes napA, narJ, nirB, norR, nosZ of P. stutzeri increased by 55.7%, 24.9%, 24.5%, 36.5%, 120% upon addition of Fe₃O₄, and that of denitrifying reductase Nap, Nar, Nir, Nor, Nos increased by 85.0%, 147%, 16.5%, 47.1%, 95.9%, respectively. No significant difference was observed on the relative expression level of denitrifying genes and denitrifying reductases between the bacteria suspended and the bacteria adhered to Fe₃O₄. Interestingly, the relative expression level of electron transfer proteins of bacteria adhered to Fe₃O₄ was higher than that of the bacteria suspended. The results indicated that Fe₃O₄ promoted cell growth and metabolism through direct contact with bacteria, thereby improving the denitrification. These findings may provide theoretical support for the development of enhanced denitrification.
Topics: Aerobiosis; Denitrification; Nitrates; Nitrogen; Pseudomonas stutzeri
PubMed: 34708620
DOI: 10.13345/j.cjb.210426 -
Nature Communications 2012Methane in the biosphere is mainly produced by prokaryotic methanogenic archaea, biomass burning, coal and oil extraction, and to a lesser extent by eukaryotic plants....
Methane in the biosphere is mainly produced by prokaryotic methanogenic archaea, biomass burning, coal and oil extraction, and to a lesser extent by eukaryotic plants. Here we demonstrate that saprotrophic fungi produce methane without the involvement of methanogenic archaea. Fluorescence in situ hybridization, confocal laser-scanning microscopy and quantitative real-time PCR confirm no contribution from microbial contamination or endosymbionts. Our results suggest a common methane formation pathway in fungal cells under aerobic conditions and thus identify fungi as another source of methane in the environment. Stable carbon isotope labelling experiments reveal methionine as a precursor of methane in fungi. These findings of an aerobic fungus-derived methane formation pathway open another avenue in methane research and will further assist with current efforts in the identification of the processes involved and their ecological implications.
Topics: Aerobiosis; Basidiomycota; Biomass; Methane; Methionine
PubMed: 22948828
DOI: 10.1038/ncomms2049 -
Medicine and Science in Sports and... May 2021
Topics: Aerobiosis; Anaerobic Threshold; Animals; Exercise; Glycogen; Glycolysis; Humans; Lactic Acid; Muscle, Skeletal
PubMed: 33844671
DOI: 10.1249/MSS.0000000000002549 -
ELife Apr 2019A comprehensive description of the phenotypic changes during cellular aging is key towards unraveling its causal forces. Previously, we mapped age-related changes in the...
A comprehensive description of the phenotypic changes during cellular aging is key towards unraveling its causal forces. Previously, we mapped age-related changes in the proteome and transcriptome (Janssens et al., 2015). Here, employing the same experimental procedure and model-based inference, we generate a comprehensive account of metabolic changes during the replicative life of . With age, we found decreasing metabolite levels, decreasing growth and substrate uptake rates accompanied by a switch from aerobic fermentation to respiration, with glycerol and acetate production. The identified metabolic fluxes revealed an increase in redox cofactor turnover, likely to combat increased production of reactive oxygen species. The metabolic changes are possibly a result of the age-associated decrease in surface area per cell volume. With metabolism being an important factor of the cellular phenotype, this work complements our recent mapping of the transcriptomic and proteomic changes towards a holistic description of the cellular phenotype during aging.
Topics: Aerobiosis; Fermentation; Metabolic Flux Analysis; Metabolism; Oxidative Phosphorylation; Saccharomyces cerevisiae
PubMed: 30963997
DOI: 10.7554/eLife.41046 -
Journal of Applied Physiology... Aug 1998Thirty physically active healthy men (20.1 +/- 1.6 yr) were randomly assigned to participate for 10 wk in one of the following training groups: endurance trained (ET; 3... (Clinical Trial)
Clinical Trial Randomized Controlled Trial
Thirty physically active healthy men (20.1 +/- 1.6 yr) were randomly assigned to participate for 10 wk in one of the following training groups: endurance trained (ET; 3 days/wk jogging and/or running), resistance trained (RT; 3 days/wk resistance training), or combined endurance and resistance trained (CT). Before and after training, basal metabolic rate (BMR), percent body fat (BF), maximal aerobic power, and one-repetition maximum for bench press and parallel squat were determined for each subject. Urinary urea nitrogen was determined pre-, mid-, and posttraining. BMR increased significantly from pre- to posttraining for RT (7,613 +/- 968 to 8,090 +/- 951 kJ/day) and CT (7,455 +/- 964 to 7,802 +/- 981 kJ/day) but not for ET (7,231 +/- 554 to 7,029 +/- 666 kJ/day). BF for CT (12.2 +/- 3.5 to 8.7 +/- 1.7%) was significantly reduced compared with RT (15.4 +/- 2.7 to 14.0 +/- 2.7%) and ET (11.8 +/- 2.9 to 9.5 +/- 1.7%). Maximal aerobic power increased significantly for ET (13%) but not RT (-0.2%) or CT (7%), whereas the improvements in one-repetition maximum bench press and parallel squat were greater in RT (24 and 23%, respectively) compared with CT (19 and 12%, respectively). Urinary urea nitrogen loss was greater in ET (14.6 +/- 0.9 g/24 h) than in RT (11.7 +/- 1.0 g/24 h) and CT (11.5 +/- 1.0 g/24 h) at the end of 10 wk of training. These data indicate that, although RT alone will increase BMR and muscular strength, and ET alone will increase aerobic power and decrease BF, CT will provide all of these benefits but to a lesser magnitude than RT and ET after 10 wk of training.
Topics: Adult; Aerobiosis; Basal Metabolism; Body Composition; Diet; Humans; Male; Metabolism; Oxygen Consumption; Physical Endurance; Physical Fitness; Urea; Weight Lifting
PubMed: 9688748
DOI: 10.1152/jappl.1998.85.2.695 -
FEMS Microbiology Reviews Dec 2000Molecular oxygen is one of the most important reactants in biogeochemical cycles. Due to its low solubility in water, the consumption of oxygen leads to the development... (Review)
Review
Molecular oxygen is one of the most important reactants in biogeochemical cycles. Due to its low solubility in water, the consumption of oxygen leads to the development of oxic-anoxic interfaces, which separate aerobic from anaerobic processes in virtually all environments, ranging in scale from oceanic sediments to the fecal pellets of a small soil invertebrate. Three case studies were selected to illustrate the basic situation and the specific characteristics of oxic-anoxic interfaces: sediments, the rhizosphere of aquatic plants, and the intestinal tract of insects. Each system is governed by the same general principles, but striking differences arise from, e.g., the nature of the major microbial activities and the mechanisms controlling metabolite fluxes. Also scale and dimensional differences as well as the consequences of temporal fluctuations are of fundamental importance. Recent developments in microbial ecology, which often combine traditional and modern approaches, have significantly furthered our understanding of the specific microniches and the metabolic and behavioral adaptations of microorganisms to life at the oxic-anoxic interface. New concepts help to define the targets of future studies: the spatial organization of microbial populations, their microenvironments and in situ activities, and the functional interactions within structured microbial communities.
Topics: Adaptation, Physiological; Aerobiosis; Anaerobiosis; Animals; Bacteria; Intestines; Isoptera; Oxygen; Water Microbiology
PubMed: 11077159
DOI: 10.1111/j.1574-6976.2000.tb00567.x