scholarly journals Lateral Acquisitions Repeatedly Remodel the Oxygen Detoxification Pathway in Diplomonads and Relatives

2019 ◽  
Vol 11 (9) ◽  
pp. 2542-2556 ◽  
Author(s):  
Alejandro Jiménez-González ◽  
Feifei Xu ◽  
Jan O Andersson
Keyword(s):  
Anaerobic Metabolism ◽  
Giardia Intestinalis ◽  
Stress Factors ◽  
Oxygen Species ◽  
Low Oxygen ◽  
Protein Families ◽  
Large Molecules ◽  
Central Oxygen ◽  
Nonprotein Thiols ◽  
Detoxification Pathway

Abstract Oxygen and reactive oxygen species (ROS) are important stress factors for cells because they can oxidize many large molecules. Fornicata, a group of flagellated protists that includes diplomonads, have anaerobic metabolism but are still able to tolerate fluctuating levels of oxygen. We identified 25 protein families putatively involved in detoxification of oxygen and ROS in this group using a bioinformatics approach and propose how these interact in an oxygen detoxification pathway. These protein families were divided into a central oxygen detoxification pathway and accessory pathways for the synthesis of nonprotein thiols. We then used a phylogenetic approach to investigate the evolutionary origin of the components of this putative pathway in Diplomonadida and other Fornicata species. Our analyses suggested that the diplomonad ancestor was adapted to low-oxygen levels, was able to reduce O2 to H2O in a manner similar to extant diplomonads, and was able to synthesize glutathione and l-cysteine. Several genes involved in the pathway have complex evolutionary histories and have apparently been repeatedly acquired through lateral gene transfer and subsequently lost. At least seven genes were acquired independently in different Fornicata lineages, leading to evolutionary convergences. It is likely that acquiring these oxygen detoxification proteins helped anaerobic organisms (like the parasitic Giardia intestinalis) adapt to low-oxygen environments (such as the digestive tract of aerobic hosts).

scholarly journals NADPH oxidase-derived ROS and the regulation of pulmonary vessel tone

2012 ◽  
Vol 302 (11) ◽  
pp. H2166-H2177 ◽  
Author(s):  
G. Frazziano ◽  
H. C. Champion ◽  
P. J. Pagano
Keyword(s):  
Oxygen Tension ◽  
Vascular Tone ◽  
Systemic Circulation ◽  
Oxygen Species ◽  
Partial Pressure Of Oxygen ◽  
Low Oxygen ◽  
Key Factors ◽  
Pulmonary Vessel ◽  
Major Emphasis

Pulmonary vessel constriction results from an imbalance between vasodilator and vasoconstrictor factors released by the endothelium including nitric oxide, endothelin, prostanoids, and reactive oxygen species (ROS). ROS, generated by a variety of enzymatic sources (such as mitochondria and NADPH oxidases, a.k.a. Nox), appear to play a pivotal role in vascular homeostasis, whereas elevated levels effect vascular disease. The pulmonary circulation is very sensitive to changes in the partial pressure of oxygen and differs from the systemic circulation in its response to this change. In fact, the pulmonary vessels contract in response to low oxygen tension, whereas systemic vessels dilate. Growing evidence suggests that ROS production and ROS-related pathways may be key factors that underlie this differential response to oxygen tension. A major emphasis of our laboratory is the role of Nox isozymes in cardiovascular disease. In this review, we will focus our attention on the role of Nox-derived ROS in the control of pulmonary vascular tone.

scholarly journals Scavenging reactive oxygen species mimics the anoxic response in goldfish pyramidal neurons

2021 ◽  
Author(s):  
Varshinie Pillai ◽  
Leslie Buck ◽  
Ebrahim Lari
Keyword(s):  
Reactive Oxygen Species ◽  
Action Potential ◽  
Pyramidal Neurons ◽  
Reactive Oxygen ◽  
Severe Hypoxia ◽  
Oxygen Species ◽  
Low Oxygen ◽  
Ros Scavenging ◽  
Patch Clamp Recording ◽  
Whole Cell

Goldfish are one of a few species able to avoid cellular damage during month-long periods in severely hypoxic environments. By suppressing action potentials in excitatory glutamatergic neurons, the goldfish brain decreases its overall energy expenditure. Co-incident with reductions in O2 availability is a natural decrease in cellular reactive oxygen species (ROS) generation, which has been proposed to function as part of a low oxygen signal transduction pathway. Therefore, using live-tissue fluorescence microscopy, we found that ROS production decreased by 10% with the onset of anoxia in goldfish telencephalic brain slices. Employing whole-cell patch-clamp recording, we found that like severe hypoxia the ROS scavengers N-acetyl cysteine (NAC) and MitoTEMPO, added during normoxic periods, depolarized membrane potential (severe hypoxia -73.6 to – 61.4 mV; NAC -76.6 to -66.2 mV; and MitoTEMPO -71.5 mV to -62.5 mV) and increased whole-cell conductance (severe hypoxia 5.7 to 8.0 nS; NAC 6 nS to 7.5 nS; and MitoTEMPO 6.0 nS to 7.6 nS). Also, in a subset of active pyramidal neurons these treatments reduced action potential firing frequency (severe hypoxia 0.18 Hz to 0.03 Hz; NAC 0.27 Hz to 0.06 Hz and MitoTEMPO 0.35 Hz to 0.08 Hz ). Neither severe hypoxia nor ROS scavenging impacted action potential threshold. The addition of exogenous hydrogen peroxide could reverse the effects of the antioxidants. Taken together, this supports a role for a reduction in [ROS] as a low oxygen signal in goldfish brain.

Survival in Hostile Environments: Strategies of Renal Medullary Cells

Physiology ◽  
2006 ◽  
Vol 21 (3) ◽  
pp. 171-180 ◽  
Author(s):  
Wolfgang Neuhofer ◽  
Franz-X. Beck
Keyword(s):  
Reactive Oxygen Species ◽  
Reactive Oxygen ◽  
Renal Medulla ◽  
Extreme Conditions ◽  
Oxygen Species ◽  
Low Oxygen ◽  
Oxygen Tensions ◽  
Hostile Environments ◽  
Medullary Cells

Cells in the renal medulla exist in a hostile milieu characterized by wide variations in extracellular solute concentrations, low oxygen tensions, and abundant reactive oxygen species. This article reviews the strategies adopted by these cells to allow them to survive and fulfill their functions under these extreme conditions.

scholarly journals Prenatal Hypoxia and Placental Oxidative Stress: Insights from Animal Models to Clinical Evidences

Antioxidants ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 414
Author(s):  
Serena Silvestro ◽  
Valeria Calcaterra ◽  
Gloria Pelizzo ◽  
Placido Bramanti ◽  
Emanuela Mazzon
Keyword(s):  
Oxidative Stress ◽  
Reproductive Function ◽  
Prenatal Hypoxia ◽  
Oxygen Species ◽  
Protective Effects ◽  
Fetal Hypoxia ◽  
Low Oxygen ◽  
Cellular Functions ◽  
Antioxidant Agents ◽  
And Oxidative Stress

Hypoxia is a common form of intrauterine stress characterized by exposure to low oxygen concentrations. Gestational hypoxia is associated with the generation of reactive oxygen species. Increase in oxidative stress is responsible for damage to proteins, lipids and DNA with consequent impairment of normal cellular functions. The purpose of this review is to propose a summary of preclinical and clinical evidences designed to outline the correlation between fetal hypoxia and oxidative stress. The results of the studies described show that increases of oxidative stress in the placenta is responsible for changes in fetal development. Specifically, oxidative stress plays a key role in vascular, cardiac and neurological disease and reproductive function dysfunctions. Moreover, the different finding suggests that the prenatal hypoxia-induced oxidative stress is associated with pregnancy complications, responsible for changes in fetal programming. In this way, fetal hypoxia predisposes the offspring to congenital anomalies and chronic diseases in future life. Several antioxidant agents, such as melatonin, erythropoietin, vitamin C, resveratrol and hydrogen, shown potential protective effects in prenatal hypoxia. However, future investigations will be needed to allow the implementation of these antioxidants in clinical practice for the promotion of health in early intrauterine life, in fetuses and children.

scholarly journals Diversity and origins of anaerobic metabolism in mitochondria and related organelles

2015 ◽  
Vol 370 (1678) ◽  
pp. 20140326 ◽  
Author(s):  
Courtney W. Stairs ◽  
Michelle M. Leger ◽  
Andrew J. Roger
Keyword(s):  
Metabolic Pathways ◽  
Anaerobic Metabolism ◽  
Low Oxygen ◽  
Metabolic Potential ◽  
Free Living ◽  
Eukaryotic Diversity ◽  
The Past ◽  
Microbial Eukaryotes ◽  
Sequencing Studies ◽  
Diversity Of Life

Across the diversity of life, organisms have evolved different strategies to thrive in hypoxic environments, and microbial eukaryotes (protists) are no exception. Protists that experience hypoxia often possess metabolically distinct mitochondria called mitochondrion-related organelles (MROs). While there are some common metabolic features shared between the MROs of distantly related protists, these organelles have evolved independently multiple times across the breadth of eukaryotic diversity. Until recently, much of our knowledge regarding the metabolic potential of different MROs was limited to studies in parasitic lineages. Over the past decade, deep-sequencing studies of free-living anaerobic protists have revealed novel configurations of metabolic pathways that have been co-opted for life in low oxygen environments. Here, we provide recent examples of anaerobic metabolism in the MROs of free-living protists and their parasitic relatives. Additionally, we outline evolutionary scenarios to explain the origins of these anaerobic pathways in eukaryotes.

scholarly journals Effects of various physical stress factors on mitochondrial function and reactive oxygen species in rat spermatozoa

2013 ◽  
Vol 25 (7) ◽  
pp. 1051 ◽  
Author(s):  
Suhee Kim ◽  
Cansu Agca ◽  
Yuksel Agca
Keyword(s):  
Reactive Oxygen Species ◽  
Membrane Integrity ◽  
Reactive Oxygen ◽  
Careful Consideration ◽  
Stress Factors ◽  
Oxygen Species ◽  
Percoll Gradient ◽  
Functional Parameters ◽  
Positive Correlations ◽  
Gradient Separation

The aim of the present study was to evaluate the effects of various physical interventions on the function of epididymal rat spermatozoa and determine whether there are correlations among these functional parameters. Epididymal rat spermatozoa were subjected to various mechanical (pipetting, centrifugation and Percoll gradient separation) and anisotonic conditions, and sperm motility, plasma membrane integrity (PMI), mitochondrial membrane potential (MMP) and intracellular reactive oxygen species (ROS) were evaluated. Repeated pipetting caused a loss in motility, PMI and MMP (P < 0.05). Minimal centrifugation force (200g) had no effect on motility, PMI and MMP, whereas an increase in the centrifugation force to 400g or 600g decreased sperm function (P < 0.005). Percoll gradient separation increased total motility, PMI and MMP (P < 0.05). However, the spermatozoa that were subjected to mechanical interventions showed high susceptibility to a ROS stimulant (P < 0.005). Anisotonic conditions decreased motility, PMI and MMP, and hypotonic conditions in particular increased basal ROS (P < 0.05). In correlation tests, there were strong positive correlations among total motility, PMI and MMP, whereas ROS showed no or negatively weak correlations with the other parameters. In conclusion, the physical interventions may act as important variables, affecting functional parameters of epididymal rat spermatozoa. Therefore, careful consideration and proper protocols for handling of rat spermatozoa and osmotic conditions are required to achieve reliable results and minimise damage.

Evaluation of different culture systems with low oxygen tension on the development, quality and oxidative stress-related genes of bovine embryos produced in vitro

Zygote ◽  
2011 ◽  
Vol 20 (3) ◽  
pp. 209-217 ◽  
Author(s):  
Maria Elena Arias ◽  
Raul Sanchez ◽  
Ricardo Felmer
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Oxygen Tension ◽  
Oxygen Species ◽  
Bovine Embryos ◽  
Low Oxygen ◽  
Culture Systems ◽  
Low Oxygen Tension ◽  
Plastic Bag ◽  
Stress Related Genes

SummaryThe present study was conducted to assess the development, quality and gene expression profile of oxidative stress-related genes of bovine embryos cultured in different culture systems with low oxygen tension (5% CO2, 5% O2 and 90% N2). The systems assessed included: (1) an incubator chamber; (2) a plastic bag; and (3) a foil bag. The choice of culture system had no effect on cleavage rate at 72 h. However, significant differences (P < 0.01) were observed in the rate of blastocysts registered at day 7 (29.8, 20.2 and 12.7% for incubator chamber, plastic bag and foil bag, respectively). Total number of cells did not differ between systems, although the proportion of ICM:total cells was affected particularly in the plastic bag (19.5%), compared with the incubator chamber (31.4%). In addition, significant differences were found in the apoptotic:total cell ratio (3.3, 6.5 and 8.8% for the incubator chamber, plastic bag and foil bag, respectively), with apoptotic nuclei localised mainly in the ICM compartment of the embryo. The amount of reactive oxygen species was also different between culture systems and this effect was correlated with a higher expression of SOD2, GSS and GPX1 genes in embryos cultured in the gassed bags as compared with embryos cultured in the incubator chamber. In conclusion, these results give evidence that, under low oxygen tension, the incubator chamber is more efficient and generates higher number of, and better quality, embryos than gassed bag systems evaluated here and this effect was probably due to an increased level of reactive oxygen species in the gassed bags, which upregulates the expression of some antioxidant enzymes to compensate for hyperoxia conditions.

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