scholarly journals Respiration enhances TDP-43 toxicity, but TDP-43 retains some toxicity in the absence of respiration

2018 ◽  
Author(s):  
Sei-Kyoung Park ◽  
Sangeun Park ◽  
Susan W Liebman
Keyword(s):  
Reactive Oxygen Species ◽  
Genetic Risk ◽  
Disease Model ◽  
Reactive Oxygen ◽  
Dna Binding Protein ◽  
Oxygen Species ◽  
Genetic Modifiers ◽  
Wild Type ◽  
Conserved Genes ◽  
Lateral Sclerosis

The trans-activating response DNA-binding protein 43 (TDP-43) is a transcriptional repressor and splicing factor. TDP-43 is normally mostly in the nucleus, although it shuttles to the cytoplasm. Mutations in TDP-43 are one cause of familial amyotrophic lateral sclerosis (ALS). In neurons of these patients, TDP-43 forms cytoplasmic aggregates. In addition, wild-type TDP-43 is also frequently found in neuronal cytoplasmic aggregates in patients with neurodegenerative diseases not caused by TDP-43 mutations. TDP-43 expressed in yeast causes toxicity and forms cytoplasmic aggregates. This disease model has been validated because genetic modifiers of TDP-43 toxicity in yeast have led to the discovery that their conserved genes in humans are ALS genetic risk factors. While how TDP-43 is associated with toxicity is unknown, several studies find that TDP-43 alters mitochondrial function. We now report that TDP-43 is much more toxic when yeast are respiring than when grown on a carbon source where respiration is inhibited. However, respiration is not the unique target of TDP-43 toxicity because we found that TDP-43 retains some toxicity even in the absence of respiration. We found that H2O2 increases the toxicity of TDP-43, suggesting that the reactive oxygen species associated with respiration could likewise enhance the toxicity of TDP-43. In this case, the TDP-43 toxicity targets in the presence or absence of respiration could be identical, with the reactive oxygen species produced by respiration activating TDP-43 to become more toxic or making TDP-43 targets more vulnerable.

scholarly journals Production and scavenging of reactive oxygen species both affect reproductive success in male and female Drosophila melanogaster

2021 ◽  
Author(s):  
Biz R. Turnell ◽  
Luisa Kumpitsch ◽  
Klaus Reinhardt
Keyword(s):  
Reactive Oxygen Species ◽  
Drosophila Melanogaster ◽  
Reactive Oxygen ◽  
Cellular Aging ◽  
Ros Production ◽  
Oxygen Species ◽  
Wild Type ◽  
Ros Scavenging ◽  
Respiratory Pathway ◽  
Male And Female

AbstractSperm aging is accelerated by the buildup of reactive oxygen species (ROS), which cause oxidative damage to various cellular components. Aging can be slowed by limiting the production of mitochondrial ROS and by increasing the production of antioxidants, both of which can be generated in the sperm cell itself or in the surrounding somatic tissues of the male and female reproductive tracts. However, few studies have compared the separate contributions of ROS production and ROS scavenging to sperm aging, or to cellular aging in general. We measured reproductive fitness in two lines of Drosophila melanogaster genetically engineered to (1) produce fewer ROS via expression of alternative oxidase (AOX), an alternative respiratory pathway; or (2) scavenge fewer ROS due to a loss-of-function mutation in the antioxidant gene dj-1β. Wild-type females mated to AOX males had increased fecundity and longer fertility durations, consistent with slower aging in AOX sperm. Contrary to expectations, fitness was not reduced in wild-type females mated to dj-1β males. Fecundity and fertility duration were increased in AOX and decreased in dj-1β females, indicating that female ROS levels may affect aging rates in stored sperm and/or eggs. Finally, we found evidence that accelerated aging in dj-1β sperm may have selected for more frequent mating. Our results help to clarify the relative roles of ROS production and ROS scavenging in the male and female reproductive systems.

scholarly journals Somatic production of reactive oxygen species does not predict its production in sperm cells across Drosophila melanogaster lines

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Biz R. Turnell ◽  
Luisa Kumpitsch ◽  
Anne-Cécile Ribou ◽  
Klaus Reinhardt
Keyword(s):  
Reactive Oxygen Species ◽  
Drosophila Melanogaster ◽  
Reactive Oxygen ◽  
Future Research ◽  
Ros Production ◽  
Oxygen Species ◽  
Loss Of Function ◽  
Wild Type ◽  
Ros Scavenging ◽  
Transport Chain

Abstract Objective Sperm ageing has major evolutionary implications but has received comparatively little attention. Ageing in sperm and other cells is driven largely by oxidative damage from reactive oxygen species (ROS) generated by the mitochondria. Rates of organismal ageing differ across species and are theorized to be linked to somatic ROS levels. However, it is unknown whether sperm ageing rates are correlated with organismal ageing rates. Here, we investigate this question by comparing sperm ROS production in four lines of Drosophila melanogaster that have previously been shown to differ in somatic mitochondrial ROS production, including two commonly used wild-type lines and two lines with genetic modifications standardly used in ageing research. Results Somatic ROS production was previously shown to be lower in wild-type Oregon-R than in wild-type Dahomey flies; decreased by the expression of alternative oxidase (AOX), a protein that shortens the electron transport chain; and increased by a loss-of-function mutation in dj-1β, a gene involved in ROS scavenging. Contrary to predictions, we found no differences among these four lines in the rate of sperm ROS production. We discuss the implications of our results, the limitations of our study, and possible directions for future research.

scholarly journals Role of mitochondrial superoxide dismutase in contraction-induced generation of reactive oxygen species in skeletal muscle extracellular space

2004 ◽  
Vol 286 (5) ◽  
pp. C1152-C1158 ◽  
Author(s):  
A. McArdle ◽  
J. van der Meulen ◽  
G. L. Close ◽  
D. Pattwell ◽  
H. Van Remmen ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Hydroxyl Radical ◽  
Hydroxyl Radicals ◽  
Extracellular Space ◽  
Superoxide Anion ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Superoxide Anions ◽  
Wild Type ◽  
Mnsod Activity

Contractions of skeletal muscles produce increases in concentrations of superoxide anions and activity of hydroxyl radicals in the extracellular space. The sources of these reactive oxygen species are not clear. We tested the hypothesis that, after a demanding isometric contraction protocol, the major source of superoxide and hydroxyl radical activity in the extracellular space of muscles is mitochondrial generation of superoxide anions and that, with a reduction in MnSOD activity, concentration of superoxide anions in the extracellular space is unchanged but concentration of hydroxyl radicals is decreased. For gastrocnemius muscles from adult (6–8 mo old) wild-type ( Sod2+/+) mice and knockout mice heterozygous for the MnSOD gene ( Sod2+/-), concentrations of superoxide anions and hydroxyl radical activity were measured in the extracellular space by microdialysis. A 15-min protocol of 180 isometric contractions induced a rapid, equivalent increase in reduction of cytochrome c as an index of superoxide anion concentrations in the extracellular space of Sod2+/+ and Sod2+/- mice, whereas hydroxyl radical activity measured by formation of 2,3-dihydroxybenzoate from salicylate increased only in the extracellular space of muscles of Sod2+/+ mice. The lack of a difference in increase in superoxide anion concentration in the extracellular space of Sod2+/+ and Sod2+/- mice after the contraction protocol supported the hypothesis that superoxide anions were not directly derived from mitochondria. In contrast, the data obtained suggest that the increase in hydroxyl radical concentration in the extracellular space of muscles from wild-type mice after the contraction protocol most likely results from degradation of hydrogen peroxide generated by MnSOD activity.

scholarly journals NADPH Oxidase-Mediated Reactive Oxygen Species Production: Subcellular Localization and Reassessment of Its Role in Plant Defense

2009 ◽  
Vol 22 (7) ◽  
pp. 868-881 ◽  
Author(s):  
Jeannine Lherminier ◽  
Taline Elmayan ◽  
Jérôme Fromentin ◽  
Khadija Tantaoui Elaraqui ◽  
Simona Vesa ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Hydrogen Peroxide ◽  
Plasma Membrane ◽  
Nadph Oxidase ◽  
Subcellular Localization ◽  
Acquired Resistance ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Wild Type ◽  
Hydrogen Peroxide Production

Chemiluminescence detection of reactive oxygen species (ROS) triggered in tobacco BY-2 cells by the fungal elicitor cryptogein was previously demonstrated to be abolished in cells transformed with an antisense construct of the plasma membrane NADPH oxidase, NtrbohD. Here, using electron microscopy, it has been confirmed that the first hydrogen peroxide production occurring a few minutes after challenge of tobacco cells with cryptogein is plasma membrane located and NtrbohD mediated. Furthermore, the presence of NtrbohD in detergent-resistant membrane fractions could be associated with the presence of NtrbohD-mediated hydrogen peroxide patches along the plasma membrane. Comparison of the subcellular localization of ROS in wild-type tobacco and in plants transformed with antisense constructs of NtrbohD revealed that this enzyme is also responsible for the hydrogen peroxide production occurring at the plasma membrane after infiltration of tobacco leaves with cryptogein. Finally, the reactivity of wild-type and transformed plants to the elicitor and their resistance against the pathogenic oomycete Phytophthora parasitica were examined. NtrbohD-mediated hydrogen peroxide production does not seem determinant for either hypersensitive response development or the establishment of acquired resistance but it is most likely involved in the signaling pathways associated with the protection of the plant cell.

scholarly journals Superoxide Dismutase Influences the Virulence of Cryptococcus neoformans by Affecting Growth within Macrophages

2003 ◽  
Vol 71 (1) ◽  
pp. 173-180 ◽  
Author(s):  
Gary M. Cox ◽  
Thomas S. Harrison ◽  
Henry C. McDade ◽  
Carlos P. Taborda ◽  
Garrett Heinrich ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Superoxide Dismutase ◽  
Cryptococcus Neoformans ◽  
Fungal Infections ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Wild Type ◽  
Pathogenic Yeast ◽  
Antioxidant Defense Systems

ABSTRACT Superoxide dismutase (SOD) is an enzyme that converts superoxide radicals into hydrogen peroxide and molecular oxygen and has been shown to contribute to the virulence of many human-pathogenic bacteria through its ability to neutralize toxic levels of reactive oxygen species generated by the host. SOD has also been speculated to be important in the pathogenesis of fungal infections, but the role of this enzyme has not been rigorously investigated. To examine the contribution of SOD to the pathogenesis of fungal infections, we cloned the Cu,Zn SOD-encoding gene (SOD1) from the human-pathogenic yeast Cryptococcus neoformans and made mutants via targeted disruption. The sod1 mutant strains had marked decreases in SOD activity and were strikingly more susceptible to reactive oxygen species in vitro. A sod1 mutant was significantly less virulent than the wild-type strain and two independent reconstituted strains, as measured by cumulative survival in the mouse inhalational model. In vitro studies established that the sod1 strain had attenuated growth compared to the growth of the wild type and a reconstituted strain inside macrophages producing reduced amounts of nitric oxide. These findings demonstrate that (i) the Cu,Zn SOD contributes to virulence but is not required for pathogenicity in C. neoformans; (ii) the decreased virulence of the sod1 strain may be due to increased susceptibility to oxygen radicals within macrophages; and (iii) other antioxidant defense systems in C. neoformans can compensate for the loss of the Cu,Zn SOD in vivo.

scholarly journals The Tomato Kinase Pti1 Contributes to Production of Reactive Oxygen Species in Response to Two Flagellin-Derived Peptides and Promotes Resistance to Pseudomonas syringae Infection

2017 ◽  
Vol 30 (9) ◽  
pp. 725-738 ◽  
Author(s):  
Simon Schwizer ◽  
Christine M. Kraus ◽  
Diane M. Dunham ◽  
Yi Zheng ◽  
Noé Fernandez-Pozo ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Pseudomonas Syringae ◽  
Severe Disease ◽  
Reactive Oxygen ◽  
Transcript Abundance ◽  
Mapk Signaling ◽  
Mitogen Activated Protein Kinase ◽  
Oxygen Species ◽  
Wild Type ◽  
Transcript Accumulation

The Pti1 kinase was identified from a reverse genetic screen as contributing to pattern-triggered immunity (PTI) against Pseudomonas syringae pv. tomato (Pst). The tomato genome has two Pti1 genes, referred to as Pti1a and Pti1b. A hairpin-Pti1 (hpPti1) construct was developed and was used to generate two independent stable transgenic tomato lines that had reduced transcript abundance of both genes. In response to P. syringae pv. tomato inoculation, these hpPti1 plants developed more severe disease symptoms, supported higher bacterial populations, and had reduced transcript accumulation of PTI-associated genes, as compared with wild-type plants. In response to two flagellin-derived peptides, the hpPti1 plants produced lesser amounts of reactive oxygen species (ROS) but showed no difference in mitogen-activated protein kinase (MAPK). Synthetic Pti1a and Pti1b genes designed to avoid silencing were transiently expressed in the hpPti1 plants and restored the ability of the plants to produce wild-type levels of ROS. Our results identify a new component of PTI in tomato that, because it affects ROS production but not MAPK signaling, appears to act early in the immune response.

scholarly journals Targeting Wild-Type and Mutant p53 with Small Molecule CP-31398 Blocks the Growth of Rhabdomyosarcoma by Inducing Reactive Oxygen Species–Dependent Apoptosis

2010 ◽  
Vol 70 (16) ◽  
pp. 6566-6576 ◽  
Author(s):  
Jianmin Xu ◽  
Laura Timares ◽  
Clay Heilpern ◽  
Zhiping Weng ◽  
Changzhao Li ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Small Molecule ◽  
Reactive Oxygen ◽  
Mutant P53 ◽  
Oxygen Species ◽  
Wild Type

scholarly journals The Characterization of TA-289, a Novel Antifungal from Fusarium sp.

2021 ◽  
Author(s):  
◽  
Natelle C H Quek
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Cell Cycle ◽  
Cell Death ◽  
Reactive Oxygen ◽  
Chemical Diversity ◽  
Mitochondrial Morphology ◽  
Ros Production ◽  
Oxygen Species ◽  
Wild Type

<p>Natural products offer vast structural and chemical diversity highly sought after in drug discovery research. Saccharomyces cerevisiae makes an ideal model eukaryotic organism for drug mode-of-action studies owing to ease of growth, sophistication of genetic tools and overall homology to higher eukaryotes. Equisetin and a closely related novel natural product, TA-289, are cytotoxic to fermenting yeast, but seemingly less so when yeast actively respire. Cell cycle analyses by flow cytometry revealed a cell cycle block at S-G2/M phase caused by TA-289; previously described oxidative stress-inducing compounds causing cell cycle delay led to further investigation in the involvement of equisetin and TA-289 in mitochondrial-mediated generation of reactive oxygen species. Chemical genomic profiling involving genome-wide scans of yeast deletion mutant strains for TA-289 sensitivity revealed sensitization of genes involved in the mitochondria, DNA damage repair and oxidative stress responses, consistent with a possible mechanism-of-action at the mitochondrion. Flow cytometric detection of reactive oxygen species (ROS) generation caused by TA-289 suggests that the compound may induce cell death via ROS production. The generation of a mutant strain resistant to TA-289 also displayed resistance to a known oxidant, H2O2, at concentrations that were cytotoxic to wild-type cells. The resistant mutant displayed a higher basal level of ROS production compared to the wild-type parent, indicating that the resistance mutation led to an up-regulation of antioxidant capacity which provides cell survival in the presence of TA-289. Yeast mitochondrial morphology was visualized by confocal light microscopy, where it was observed that cells treated with TA-289 displayed abnormal mitochondria phenotypes, further indicating that the compound is acting primarily at the mitochondrion. Similar effects observed with equisetin treatment suggest that both compounds share the same mechanism, eliciting cell death via ROS production in the mitochondrial respiratory chain.</p>

scholarly journals Auranofin resistance in Toxoplasma gondii decreases the accumulation of reactive oxygen species but does not target parasite thioredoxin reductase

2020 ◽  
Author(s):  
Christopher I. Ma ◽  
James A. Tirtorahardjo ◽  
Sharon Jan ◽  
Sakura S. Schweizer ◽  
Shawn A. C. Rosario ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Toxoplasma Gondii ◽  
Point Mutations ◽  
Thioredoxin Reductase ◽  
Reactive Oxygen ◽  
Chemical Mutagenesis ◽  
Resistance Locus ◽  
Sequencing Analysis ◽  
Oxygen Species ◽  
Wild Type

ABSTRACTAuranofin, a reprofiled FDA-approved drug originally designed to treat rheumatoid arthritis, has emerged as a promising anti-parasitic drug. It induces the accumulation of reactive oxygen species (ROS) in parasites, including Toxoplasma gondii. We generated auranofin resistant T. gondii lines through chemical mutagenesis in order to identify the molecular target of this drug. Resistant clones were confirmed with a competition assay using wild-type T. gondii expressing yellow fluorescence protein (YFP) as a reference strain. The predicted auranofin target, thioredoxin reductase, was not mutated in any of our resistant lines. Subsequent whole genomic sequencing analysis (WGS) did not reveal a consensus resistance locus, although many have point mutations in genes encoding redox-relevant proteins such as superoxide dismutase (TgSOD2) and ribonucleotide reductase. We investigated the SOD2 L201P mutation and found that it was not sufficient to confer resistance when introduced into wild-type parasites. Resistant clones accumulated less ROS than their wild type counterparts. Our results demonstrate that resistance to auranofin in T. gondii enhances its ability to abate oxidative stress through diverse mechanisms. This evidence supports a hypothesized mechanism of auranofin anti-parasitic activity as disruption of redox homeostasis.

scholarly journals Proteins Needed to Activate a Transcriptional Response to the Reactive Oxygen Species Singlet Oxygen

mBio ◽  
2013 ◽  
Vol 4 (1) ◽  
Author(s):  
Tae-Wook Nam ◽  
Eva C. Ziegelhoffer ◽  
Rachelle A. S. Lemke ◽  
Timothy J. Donohue
Keyword(s):  
Reactive Oxygen Species ◽  
Stress Response ◽  
Singlet Oxygen ◽  
Rhodobacter Sphaeroides ◽  
Transcriptional Response ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Wild Type ◽  
Content Type ◽  
Σ Factor

ABSTRACT Singlet oxygen (1O2) is a reactive oxygen species generated by energy transfer from one or more excited donors to molecular oxygen. Many biomolecules are prone to oxidation by 1O2, and cells have evolved systems to protect themselves from damage caused by this compound. One way that the photosynthetic bacterium Rhodobacter sphaeroides protects itself from 1O2 is by inducing a transcriptional response controlled by ChrR, an anti-σ factor which releases an alternative sigma factor, σE, in the presence of 1O2. Here we report that induction of σE-dependent gene transcription is decreased in the presence of 1O2 when two conserved genes in the σE regulon are deleted, including one encoding a cyclopropane fatty acid synthase homologue (RSP2144) or one encoding a protein of unknown function (RSP1091). Thus, we conclude that RSP2144 and RSP1091 are each necessary to increase σE activity in the presence of 1O2. In addition, we found that unlike in wild-type cells, where ChrR is rapidly degraded when 1O2 is generated, turnover of this anti-σ factor is slowed when cells lacking RSP2144, RSP1091, or both of these proteins are exposed to 1O2. Further, we demonstrate that the organic hydroperoxide tert-butyl hydroperoxide promotes ChrR turnover in both wild-type cells and mutants lacking RSP2144 or RSP1091, suggesting differences in the ways different types of oxidants increase σE activity. IMPORTANCE Oxygen serves many crucial functions on Earth; it is produced during photosynthesis and needed for other pathways. While oxygen is relatively inert, it can be converted to reactive oxygen species (ROS) that destroy biomolecules, cause disease, or kill cells. When energy is transferred to oxygen, the ROS singlet oxygen is generated. To understand how singlet oxygen impacts cells, we study the stress response to this ROS in Rhodobacter sphaeroides, a bacterium that, like plants, generates this compound as a consequence of photosynthesis. This paper identifies proteins that activate a stress response to singlet oxygen and shows that they act in a specific response to this ROS. The identified proteins are found in many free-living, symbiotic, or pathogenic bacteria that can encounter singlet oxygen in nature. Thus, our findings provide new information about a stress response to a ROS of broad biological, agricultural, and biomedical importance.

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