-
Nature Reviews. Cancer Dec 2008During the past century it has been established that regions within solid tumours experience mild to severe O(2) deprivation owing to aberrant vascular function. These... (Review)
Review
During the past century it has been established that regions within solid tumours experience mild to severe O(2) deprivation owing to aberrant vascular function. These hypoxic regions are associated with altered cellular metabolism, as well as increased resistance to radiation and chemotherapy. As discussed in this Timeline, over the past decade work from many laboratories has elucidated the mechanisms by which hypoxia-inducible factors (HIFs) modulate tumour cell metabolism, angiogenesis, growth and metastasis. The central role played by intra-tumoural hypoxia and HIF in these processes has made them attractive therapeutic targets in the treatment of multiple human malignancies.
Topics: Aerobiosis; Animals; Basic Helix-Loop-Helix Transcription Factors; Cell Division; Cell Hypoxia; Glycolysis; Humans; Models, Animal; Necrosis; Neoplasms; Oxygen Consumption
PubMed: 18987634
DOI: 10.1038/nrc2540 -
Journal of Agricultural and Food... Sep 2022In this study, the complex volatilome of maize silage samples conserved for 229 d, inoculated with () and (), is explored by means of advanced fingerprinting...
In this study, the complex volatilome of maize silage samples conserved for 229 d, inoculated with () and (), is explored by means of advanced fingerprinting methodologies based on comprehensive two-dimensional gas chromatography and time-of-flight mass spectrometry. The combined untargeted and targeted (UT) fingerprinting strategy covers 452 features, 269 of which were putatively identified and assigned within their characteristic classes. The high amounts of short-chain free fatty acids and alcohols were produced by fermentation and led to a large number of esters. The impact of fermentation was not clearly distinguishable from the control samples; however, had a strong and distinctive signature that was dominated by propionic acid and 1-propanol characteristic volatiles. The approach provides a better understanding of silage stabilization mechanisms against the degradative action of yeasts and molds during the exposure of silage to air.
Topics: 1-Propanol; Aerobiosis; Fatty Acids, Nonesterified; Lactobacillus; Lacticaseibacillus paracasei; Propionates; Silage; Zea mays
PubMed: 36103255
DOI: 10.1021/acs.jafc.2c03652 -
Clinical Microbiology and Infection :... 2001This review presents data on in vitro susceptibilities of aerobically growing Gram-positive rods and in vivo activities of antibiotics used against Gram-positive rods.... (Review)
Review
This review presents data on in vitro susceptibilities of aerobically growing Gram-positive rods and in vivo activities of antibiotics used against Gram-positive rods. While in some instances susceptibility and efficacy are predictable (e.g. penicillin vs. Listeria and microaerophilic coryneforms, or metronidazole vs. Gardnerella) susceptibility testing by dilution techniques seems necessary for many Gram-positive rods as long as they are deemed clinically relevant.
Topics: Aerobiosis; Anti-Bacterial Agents; Gram-Positive Bacterial Infections; Gram-Positive Rods; Humans; Microbial Sensitivity Tests
PubMed: 11688533
DOI: 10.1046/j.1469-0691.2001.00057.x -
International Journal of Environmental... Nov 2022Aerobic granular sludge (AGS) is a promising technology for wastewater treatment. AGS formation belongs to microbial self-aggregation. Investigation of the formation and...
Aerobic granular sludge (AGS) is a promising technology for wastewater treatment. AGS formation belongs to microbial self-aggregation. Investigation of the formation and stability of AGS is widely paid attention to, in particular the structure stability of large size granules. Two types of AGS were developed in two sequencing batch reactors fed by two different wastewaters, respectively. Through confocal laser scanning microscope (CLSM) and scanning electron microscopy (SEM), the structure and composition of granules were analyzed. Filamentous bacteria were observed in granules from synthetic wastewater reactor, while filamentous bacteria and stalked ciliates ( sp.) were simultaneously found in granules from domestic wastewater reactor. The analytic results show that filamentous bacteria and stalked ciliates acting as skeletons play important roles in the formation and stability of granules. With the bonding of extracellular polymeric substances (EPS), the filamentous bacteria and stalked ciliates could build bridges and frames to promote the aggregation of bacteria; these microorganisms could create a space grid structure around the surface layer of granules to enhance the strength of granules, and the remnants of the stalks could serve as supports to fix the steadiness of granules.
Topics: Sewage; Wastewater; Waste Disposal, Fluid; Bioreactors; Aerobiosis; Bacteria
PubMed: 36497821
DOI: 10.3390/ijerph192315747 -
Astrobiology Oct 2019Observational evidence supports the presence of methane (CH) in the martian atmosphere on the order of parts per billion by volume (ppbv). Here, we assess whether...
Observational evidence supports the presence of methane (CH) in the martian atmosphere on the order of parts per billion by volume (ppbv). Here, we assess whether aerobic methanotrophy is a potentially viable metabolism in the martian upper regolith, by calculating metabolic energy gain rates under assumed conditions of martian surface temperature, pressure, and atmospheric composition. Using kinetic parameters for 19 terrestrial aerobic methanotrophic strains, we show that even under the imposed low temperature and pressure extremes (180-280 K and 6-11 hPa), methane oxidation by oxygen (O) should in principle be able to generate the minimum energy production rate required to support endogenous metabolism (, cellular maintenance). Our results further indicate that the corresponding metabolic activity would be extremely low, with cell doubling times in excess of 4000 Earth years at the present-day ppbv-level CH mixing ratios in the atmosphere of Mars. Thus, while aerobic methanotrophic microorganisms similar to those found on Earth could theoretically maintain their vital functions, they are unlikely to constitute prolific members of hypothetical martian soil communities.
Topics: Aerobiosis; Euryarchaeota; Extraterrestrial Environment; Kinetics; Mars; Methane; Oxidation-Reduction; Temperature
PubMed: 31173512
DOI: 10.1089/ast.2018.1943 -
Scientific Reports Jun 2021Soil microorganisms and their activities are essential for maintaining soil health and fertility. Microorganisms can be negatively affected by application of herbicides....
Soil microorganisms and their activities are essential for maintaining soil health and fertility. Microorganisms can be negatively affected by application of herbicides. Although effects of herbicides on microorganisms are widely studied, there is a lack of information for chloroacetamide herbicide dimethachlor. Thus, dimethachlor and well known linuron were applied to silty-loam luvisol and their effects on microorganisms were evaluated during112 days long laboratory assay. Dimethachlor and linuron were applied in doses 1.0 kg ha and 0.8 kg ha corresponding to 3.33 mg kg and 2.66 mg kg respectively. Also 100-fold doses were used for magnification of impacts. Linuron in 100-fold dose caused minor increase of respiration, temporal increase of soil microbial biomass, decrease of soil dehydrogenase activity, and altered microbial community. Dimethachlor in 100-fold dose significantly increased respiration; microbial biomass and decreased soil enzymatic activities. Microbial composition changed significantly, Proteobacteria abundance, particularly Pseudomonas and Achromobacter genera increased from 7 to 28th day. In-silico prediction of microbial gene expression by PICRUSt2 software revealed increased expression of genes related to xenobiotic degradation pathways. Evaluated characteristics of microbial community and activity were not affected by herbicides in recommended doses and the responsible use of both herbicides will not harm soil microbial community.
Topics: Acetamides; Aerobiosis; Biomass; Carbon Dioxide; Herbicides; Linuron; Metabolic Networks and Pathways; Microbiota; Phylogeny; Soil Microbiology
PubMed: 34140550
DOI: 10.1038/s41598-021-91755-6 -
BMC Evolutionary Biology Jan 2019Among the four bases, guanine is the most susceptible to damage from oxidative stress. Replication of DNA containing damaged guanines results in G to T mutations....
BACKGROUND
Among the four bases, guanine is the most susceptible to damage from oxidative stress. Replication of DNA containing damaged guanines results in G to T mutations. Therefore, the mutations resulting from oxidative DNA damage are generally expected to predominantly consist of G to T (and C to A when the damaged guanine is not in the reference strand) and result in decreased GC content. However, the opposite pattern was reported 16 years ago in a study of prokaryotic genomes. Although that result has been widely cited and confirmed by nine later studies with similar methods, the omission of the effect of shared ancestry requires a re-examination of the reliability of the results.
RESULTS
When aerobic and obligate aerobic prokaryotes were mixed together and anaerobic and obligate anaerobic prokaryotes were mixed together, phylogenetic controlled analyses did not detect significant difference in GC content between aerobic and anaerobic prokaryotes. This result is consistent with two generally neglected studied that had accounted for the phylogenetic relationship. However, when obligate aerobic prokaryotes were compared with aerobic prokaryotes, anaerobic prokaryotes, and obligate anaerobic prokaryotes separately using phylogenetic regression analysis, a significant positive association was observed between aerobiosis and GC content, no matter it was calculated from whole genome sequences or the 4-fold degenerate sites of protein-coding genes. Obligate aerobes have significantly higher GC content than aerobes, anaerobes, and obligate anaerobes.
CONCLUSIONS
The positive association between aerobiosis and GC content could be attributed to a mutational force resulting from incorporation of damaged deoxyguanosine during DNA replication rather than oxidation of the guanine nucleotides within DNA sequences. Our results indicate a grade in the aerobiosis-associated mutational force, strong in obligate aerobes, moderate in aerobes, weak in anaerobes and obligate anaerobes.
Topics: Aerobiosis; Anaerobiosis; Base Composition; Humans; Least-Squares Analysis; Phylogeny; Prokaryotic Cells; Regression Analysis; Reproducibility of Results
PubMed: 30691392
DOI: 10.1186/s12862-019-1365-8 -
Water Research May 2021The aerobic granular sludge (AGS) process is an effective wastewater treatment technology for organic matter and nutrient removal that has been introduced in the market...
The aerobic granular sludge (AGS) process is an effective wastewater treatment technology for organic matter and nutrient removal that has been introduced in the market rapidly. Until now, limited information is available on AGS regarding the removal of bacterial and viral pathogenic organisms present in sewage. This study focussed on determining the relation between reactor operational conditions (plug flow feeding, turbulent aeration and settling) and physical and biological mechanisms on removing two faecal surrogates, Escherichia coli and MS2 bacteriophages. Two AGS laboratory-scale systems were separately fed with influent spiked with 1.0 × 10 CFU/100 mL of E. coli and 1.3 × 10 PFU/100 mL of MS2 bacteriophages and followed during the different operational phases. The reactors contained only granular sludge and no flocculent sludge. Both systems showed reductions in the liquid phase of 0.3 Log during anaerobic feeding caused by a dilution factor and attachment of the organisms on the granules. Higher removal efficiencies were achieved during aeration, approximately 1 Log for E. coli and 0.6 Log for the MS2 bacteriophages caused mainly by predation. The 18S sequencing analysis revealed high operational taxonomic units (OTUs) of free-living protozoa genera Rhogostoma and Telotrochidium concerning the whole eukaryotic community. Attached ciliates propagated after the addition of the E. coli, an active contribution of the genera Epistylis, Vorticella, and Pseudovorticella was found when the reactor reached stability. In contrast, no significant growth of predators occurred when spiking the system with MS2 bacteriophages, indicating a low contribution of protozoa on the phage removal. Settling did not contribute to the removal of the studied bacterial and viral surrogates.
Topics: Aerobiosis; Bioreactors; Escherichia coli; Sewage; Waste Disposal, Fluid; Water Purification
PubMed: 33714012
DOI: 10.1016/j.watres.2021.116992 -
International Journal of Molecular... Nov 2021Melatonin is synthesized in the pineal gland at night. Since melatonin is produced in the mitochondria of all other cells in a non-circadian manner, the amount... (Review)
Review
Melatonin is synthesized in the pineal gland at night. Since melatonin is produced in the mitochondria of all other cells in a non-circadian manner, the amount synthesized by the pineal gland is less than 5% of the total. Melatonin produced in mitochondria influences glucose metabolism in all cells. Many pathological cells adopt aerobic glycolysis (Warburg effect) in which pyruvate is excluded from the mitochondria and remains in the cytosol where it is metabolized to lactate. The entrance of pyruvate into the mitochondria of healthy cells allows it to be irreversibly decarboxylated by pyruvate dehydrogenase (PDH) to acetyl coenzyme A (acetyl-CoA). The exclusion of pyruvate from the mitochondria in pathological cells prevents the generation of acetyl-CoA from pyruvate. This is relevant to mitochondrial melatonin production, as acetyl-CoA is a required co-substrate/co-factor for melatonin synthesis. When PDH is inhibited during aerobic glycolysis or during intracellular hypoxia, the deficiency of acetyl-CoA likely prevents mitochondrial melatonin synthesis. When cells experiencing aerobic glycolysis or hypoxia with a diminished level of acetyl-CoA are supplemented with melatonin or receive it from another endogenous source (pineal-derived), pathological cells convert to a more normal phenotype and support the transport of pyruvate into the mitochondria, thereby re-establishing a healthier mitochondrial metabolic physiology.
Topics: Aerobiosis; Cell Communication; Glucose; Glycolysis; Humans; Melatonin; Mitochondria; Neoplasms; Warburg Effect, Oncologic
PubMed: 34830375
DOI: 10.3390/ijms222212494 -
Applied and Environmental Microbiology Feb 2023Psychrophilic bacteria with aerobic denitrification ability have promising potential for application in nitrogen-contaminated wastewater treatment, especially under cold...
Psychrophilic bacteria with aerobic denitrification ability have promising potential for application in nitrogen-contaminated wastewater treatment, especially under cold conditions. A better understanding of the cold adaptation mechanism during aerobic denitrification would be beneficial for the practical application of this type of functional bacterium. In this study, Bacillus simplex H-b with good denitrification performance at 5°C was used to investigate the corresponding cold tolerance mechanism. Transcriptomics and nitrogen removal characterization experiments were conducted at different temperatures (5°C, 20°C, and 30°C). At low temperatures, more nitrogen was utilized for assimilation, accompanied by the accumulation of ATP and extracellular polymeric substances (EPS), rather than transforming inorganic nitrogen in the dissimilation pathway. In addition, the proportion of unsaturated fatty acids was higher in strains cultured at low temperatures. At the molecular level, the adjustment of membrane transport, synthesis of cofactors and vitamins, and transcriptional regulators might contribute to the survival of the strain under cold conditions. Moreover, nucleotide precursor synthesis, translation, and oxidative and temperature stress response mechanisms also enhanced the resistance of strain H-b to low temperatures. The results suggest that combining multiple regulatory mechanisms and synergistic adaptation to cold stress enabled the growth and relatively high nitrogen removal rate (27.22%) of strain H-b at 5°C. By clarifying the mechanism of regulation and cold resistance of strain H-b, a theoretical foundation for enhancing the application potential of this functional bacterium for nitrogen-contaminated wastewater treatment was provided. The newly isolated aerobic denitrifying bacterium Bacillus simplex H-b removed various forms of inorganic nitrogen (nitrate, nitrite, and ammonium) from wastewater, even when the temperature was as low as 5°C. Although this environmentally functional bacterium has been suggested as a promising candidate for nitrogen-contaminated water treatment at low temperatures, understanding its cold adaptation mechanism during aerobic denitrification is limited. In this study, the cold tolerance mechanism of this strain was comprehensively explained. Furthermore, a theoretical basis for the practical application of this type of functional bacterium for nitrogen removal in cold regions is provided. The study expands our understanding of the survival strategy of psychrophilic bacteria and hence supports their further utilization in wastewater treatment applications.
Topics: Denitrification; Nitrification; Aerobiosis; Nitrites; Nitrates; Bacteria; Nitrogen; Heterotrophic Processes
PubMed: 36656033
DOI: 10.1128/aem.01928-22