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Current Issues in Molecular Biology 2017This review covers some recent advances in application of omics technologies to studying methylotrophs, with special reference to their activities in natural... (Review)
Review
This review covers some recent advances in application of omics technologies to studying methylotrophs, with special reference to their activities in natural environments. Some of the developments highlighted in this review are the new outlook at the role of the XoxF-type, lanthanum-dependent methanol dehydrogenase in natural habitats, new mechanistic details of methane oxidation through the reverse methanogenesis pathway, propensity of 'aerobic' methanotrophs to thrive in hypoxic environments and potential connection of this process to denitrification, and a novel outlook at methane oxidation as a community function.
Topics: Aerobiosis; Anaerobiosis; Bacteria; Metabolomics; Metagenomics; Methane; Methanol; Microbial Consortia; Proteomics
PubMed: 28686571
DOI: 10.21775/cimb.024.119 -
Plant Physiology Feb 2018Knowledge of the genetic regulation of adventitious roots, aerenchyma, and radial oxygen loss barrier formation, and the signaling for acclimation, will assist the... (Review)
Review
Knowledge of the genetic regulation of adventitious roots, aerenchyma, and radial oxygen loss barrier formation, and the signaling for acclimation, will assist the development of waterlogging-tolerant crops.
Topics: Adaptation, Physiological; Aerobiosis; Air; Floods; Plant Physiological Phenomena; Plant Roots; Plants; Soil; Stress, Physiological; Water
PubMed: 29118247
DOI: 10.1104/pp.17.01157 -
Journal of Bacteriology Apr 2019l-Carnitine is a trimethylammonium compound mostly known for its contribution to fatty acid transport into mitochondria. In bacteria, it is synthesized from...
l-Carnitine is a trimethylammonium compound mostly known for its contribution to fatty acid transport into mitochondria. In bacteria, it is synthesized from γ-butyrobetaine (GBB) and can be used as a carbon source. l-Carnitine can be formed directly by GBB hydroxylation or synthesized via a biosynthetic route analogous to fatty acid degradation. However, this multistep pathway has not been experimentally characterized. In this work, we identified by gene context analysis a cluster of l-carnitine anabolic genes next to those involved in its catabolism and proceeded to the complete characterization of l-carnitine biosynthesis and degradation in The five enzymes catalyzing the seven steps that convert GBB to glycine betaine are described. Metabolomic analysis confirmed the multistage synthesis of l-carnitine in GBB-grown cells but also revealed that GBB is synthesized by To our knowledge, this is the first report of aerobic GBB synthesis in bacteria. The conservation of l-carnitine metabolism genes in different bacterial taxonomic classes underscores the role of l-carnitine as a ubiquitous nutrient. The experimental characterization of novel metabolic pathways is essential for realizing the value of genome sequences and improving our knowledge of the enzymatic capabilities of the bacterial world. However, 30% to 40% of genes of a typical genome remain unannotated or associated with a putative function. We used enzyme kinetics, liquid chromatography-mass spectroscopy (LC-MS)-based metabolomics, and mutant phenotyping for the characterization of the metabolism of l-carnitine in to provide an accurate annotation of the corresponding genes. The occurrence of conserved gene clusters for carnitine metabolism in soil, plant-associated, and marine bacteria underlines the environmental abundance of carnitine and suggests this molecule might make a significant contribution to ecosystem nitrogen and carbon cycling.
Topics: Aerobiosis; Betaine; Biotransformation; Carnitine; Metabolic Networks and Pathways; Metabolomics; Multigene Family; Sinorhizobium meliloti
PubMed: 30670548
DOI: 10.1128/JB.00772-18 -
ELife Jun 2017Vertebrate photoreceptors are among the most metabolically active cells, exhibiting a high rate of ATP consumption. This is coupled with a high anabolic demand,...
Vertebrate photoreceptors are among the most metabolically active cells, exhibiting a high rate of ATP consumption. This is coupled with a high anabolic demand, necessitated by the diurnal turnover of a specialized membrane-rich organelle, the outer segment, which is the primary site of phototransduction. How photoreceptors balance their catabolic and anabolic demands is poorly understood. Here, we show that rod photoreceptors in mice rely on glycolysis for their outer segment biogenesis. Genetic perturbations targeting allostery or key regulatory nodes in the glycolytic pathway impacted the size of the outer segments. Fibroblast growth factor signaling was found to regulate glycolysis, with antagonism of this pathway resulting in anabolic deficits. These data demonstrate the cell autonomous role of the glycolytic pathway in outer segment maintenance and provide evidence that aerobic glycolysis is part of a metabolic program that supports the biosynthetic needs of a normal neuronal cell type.
Topics: Aerobiosis; Animals; Fibroblast Growth Factors; Glycolysis; Metabolism; Mice; Organelle Biogenesis; Retinal Rod Photoreceptor Cells; Signal Transduction
PubMed: 28598329
DOI: 10.7554/eLife.25946 -
Anaerobe Apr 2017The microbiota of the gut has many crucial functions in human health. Dysbiosis of the microbiota has been correlated to a large and still increasing number of diseases.... (Review)
Review
The microbiota of the gut has many crucial functions in human health. Dysbiosis of the microbiota has been correlated to a large and still increasing number of diseases. Recent studies have mostly focused on analyzing the associations between disease and an aberrant microbiota composition. Functional studies using (in vitro) gut models are required to investigate the precise interactions that occur between specific bacteria (or bacterial mixtures) and gut epithelial cells. As most gut bacteria are obligate or facultative anaerobes, studying their effect on oxygen-requiring human gut epithelial cells is technically challenging. Still, several (anaerobic) bacterial-epithelial co-culture systems have recently been developed that mimic host-microbe interactions occurring in the human gut, including 1) the Transwell "apical anaerobic model of the intestinal epithelial barrier", 2) the Host-Microbiota Interaction (HMI) module, 3) the "Human oxygen-Bacteria anaerobic" (HoxBan) system, 4) the human gut-on-a-chip and 5) the HuMiX model. This review discusses the role of gut microbiota in health and disease and gives an overview of the characteristics and applications of these novel host-microbe co-culture systems.
Topics: Aerobiosis; Anaerobiosis; Coculture Techniques; Gastrointestinal Tract; Host-Pathogen Interactions; Humans; Models, Biological
PubMed: 28062270
DOI: 10.1016/j.anaerobe.2017.01.001 -
Microbiology (Reading, England) Mar 2018The mineral sulfide-oxidising Acidithiobacillus ferrooxidans has been extensively studied over many years but some fundamental aspects of its metabolism remain... (Comparative Study)
Comparative Study
The mineral sulfide-oxidising Acidithiobacillus ferrooxidans has been extensively studied over many years but some fundamental aspects of its metabolism remain uncertain, particularly with regard to its anaerobic oxidation of sulfur. This label-free, liquid chromatography-electron spray ionisation-mass spectrometry-based proteomic analysis estimated relative protein abundance during aerobic and anaerobic growth of At. ferrooxidans. One of its two bc1 complexes, that encoded by the petII operon, was strongly implicated in anaerobic ferric iron-coupled sulfur oxidation, probably in conjunction with two cytochromes. These two cytochromes are homologs of the Cyc2 and Cyc1 proteins that are involved in ferrous iron oxidation. The previously undetected cytochromes apparently associated with anaerobic growth in At. ferrooxidans appear to be absent in many other ferrous iron-oxidising acidophiles that can also reduce ferric iron, which suggests a diversity in the ferric-iron-coupled sulfur oxidation pathways. For aerobic growth of At. ferrooxidans, this analysis was consistent with the generally accepted mechanism for its oxidation of ferrous iron. Unexpectedly, proteins encoded by the petI operon were not abundant and generally not detected in the proteomic analyses of cells grown aerobically on sulfur, although there was some expression of genes of the petI and petII operons in these cells.
Topics: Acidithiobacillus; Aerobiosis; Anaerobiosis; Bacterial Proteins; Cytochromes; Ferrous Compounds; Gene Expression Profiling; Iron; Operon; Oxidation-Reduction; Proteomics; Sulfur
PubMed: 29458663
DOI: 10.1099/mic.0.000616 -
PloS One 2016Aerobic and respiratory cultivations provide benefits for some lactic acid bacteria (LAB). Growth, metabolites, enzymatic activities (lactate dehydrogenase; pyruvate and...
Aerobic and respiratory cultivations provide benefits for some lactic acid bacteria (LAB). Growth, metabolites, enzymatic activities (lactate dehydrogenase; pyruvate and NADH oxidases, NADH peroxidase; catalase), antioxidant capability and stress tolerance of Lactobacillus casei N87 were evaluated in anaerobic, aerobic and respiratory (aerobiosis with heme and menaquinone supplementation) batch cultivations with different dissolved oxygen (DO) concentrations. The expression of pox (pyruvate oxidase) and cydABCD operon (cytochrome bd oxidase complex) was quantified by quantitative Real Time polymerase chain reaction. Respiration increased biomass production compared to anaerobiosis and unsupplemented aerobiosis, and altered the central metabolism rerouting pyruvate away from lactate accumulation. All enzymatic activities, except lactate dehydrogenase, were higher in respiratory cultures, while unsupplemented aerobiosis with 60% of DO promoted H2O2 and free radical accumulation. Respiration improved the survival to oxidative and freeze-drying stresses, while significant numbers of dead, damaged and viable but not cultivable cells were found in unsupplemented aerobic cultures (60% DO). Analysis of gene expression suggested that the activation of aerobic and respiratory pathways occurred during the exponential growth phase, and that O2 and hemin induced, respectively, the transcription of pox and cydABCD genes. Respiratory cultivation might be a natural strategy to improve functional and technological properties of L. casei.
Topics: Aerobiosis; Anaerobiosis; Antioxidants; Biological Transport; Gene Expression Regulation, Bacterial; Heme; Kinetics; Lacticaseibacillus casei; Operon; Oxidative Stress; Oxygen; Vitamin K 2
PubMed: 27812097
DOI: 10.1371/journal.pone.0164065 -
Journal of Applied Microbiology Apr 2017This review outlines the recent advances in the knowledge on aerobic and respiratory growth of lactic acid bacteria, focusing on the features of respiration-competent... (Review)
Review
This review outlines the recent advances in the knowledge on aerobic and respiratory growth of lactic acid bacteria, focusing on the features of respiration-competent lactobacilli. The species of the genus Lactobacillus have been traditionally classified as oxygen-tolerant anaerobes, but it has been demonstrated that several strains are able to use oxygen as a substrate in reactions mediated by flavin oxidases and, in some cases, to synthesize a minimal respiratory chain. The occurrence of genes related to aerobic and respiratory metabolism and to oxidative stress response apparently correlates with the taxonomic position of lactobacilli. Members of the ecologically versatile Lactobacillus casei, L. plantarum and L. sakei groups are apparently best equipped to deal with aerobic/respiratory growth. The shift from anaerobic growth to aerobic (oxygen) and/or respiratory promoting (oxygen, exogenous haem and menaquinone) conditions offers physiological advantages and affects the pattern of metabolite production in several species. Even if this does not result in dramatic increases in biomass production and growth rate, cells grown in these conditions have improved tolerance to heat and oxidative stresses. An overview of benefits and of the potential applications of Lactobacillus cultures grown under aerobic or respiratory conditions is also discussed.
Topics: Aerobiosis; Food Industry; Industrial Microbiology; Lactobacillus; Oxidative Stress; Oxygen
PubMed: 28063197
DOI: 10.1111/jam.13399 -
Infectious Diseases in Obstetrics and... 2020Aerobic vaginitis (AV) is an aberration within the balanced vaginal microbiota. Only few reports have documented the adverse pregnancy outcomes related to AV.... (Observational Study)
Observational Study
BACKGROUND
Aerobic vaginitis (AV) is an aberration within the balanced vaginal microbiota. Only few reports have documented the adverse pregnancy outcomes related to AV. Nonetheless, the exact role of AV in pregnancy and the potential benefit of its screening need further study. Our goal was to evaluate the association between aerobic vaginitis (AV) in late pregnancy and maternal and neonatal outcomes.
METHODS
In this prospective observational study, a total of 600 singleton pregnant women with intact fetal membranes at a gestational age of 34-36 weeks were recruited (one hundred women with AV and 500 pregnant women without AV). The study protocol excluded patients with other forms of vaginal infection. Pregnancy outcomes were traced and documented. The primary outcome was the association between AV and preterm labor. The current study compared the maternal and neonatal outcomes among pregnant women with and without AV in unadjusted and adjusted analyses with the odds ratio (OR) and 95% confidence interval (CI) reported.
RESULTS
There was an association between AV and with preterm birth (adjusted OR 3.06, 95% CI 1.58-5.95) and prelabor rupture of membranes (adjusted OR 6.17, 95% CI 3.24-11.7). For neonatal outcomes, AV was associated with a higher incidence of neonatal ICU admission (adjusted OR 2.19, 95% CI 1.1-4.34). Severe forms of AV significantly increased the incidence of PTB ( = 0.0014) and PROM ( = 0.0094) when compared to less severe forms of AV.
CONCLUSION
AV is common in late pregnancy and is linked to a diversity of adversative pregnancy outcomes including preterm birth, PROM, and neonatal ICU admission. Moreover, the incidence of PTB and PROM might further increase with the severity of AV. Clinicians should pay more consideration to vaginal microbiota assessment during pregnancy.
Topics: Adult; Aerobiosis; Female; Gestational Age; Humans; Intensive Care, Neonatal; Pregnancy; Pregnancy Complications, Infectious; Pregnancy Outcome; Premature Birth; Prospective Studies; Severity of Illness Index; Vaginitis
PubMed: 32395067
DOI: 10.1155/2020/5842150 -
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