Enzyme activities associated with oxidative stress in Metarhizium anisopliae during germination, mycelial growth, and conidiation and in response to near-UV irradiation

2004 ◽  
Vol 50 (1) ◽  
pp. 41-49 ◽  
Author(s):  
Charles D Miller ◽  
Drauzio Rangel ◽  
Gilberto UL Braga ◽  
Stephan Flint ◽  
Sun-Il Kwon ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Superoxide Dismutase ◽  
Glutathione Reductase ◽  
Stress Responses ◽  
Resistant Strain ◽  
Metarhizium Anisopliae ◽  
Specific Activity ◽  
Major Effect ◽  
Solar Irradiation ◽  
Catalase Peroxidase

Metarhizium anisopliae isolates have a wide insect host range, but an impediment to their commercial use as a biocontrol agent of above-ground insects is the high susceptibility of spores to the near-UV present in solar irradiation. To understand stress responses in M. anisopliae, we initiated studies of enzymes that protect against oxidative stress in two strains selected because their spores differed in sensitivity to UV-B. Spores of the more near-UV resistant strain in M. anisopliae 324 displayed different isozyme profiles for catalase–peroxidase, glutathione reductase, and superoxide dismutase when compared with the less resistant strain 2575. A transient loss in activity of catalase–peroxidase and glutathione reductase was observed during germination of the spores, whereas the intensity of isozymes displaying superoxide dismutase did not change as the mycelium developed. Isozyme composition for catalase–peroxidases and glutathione reductase in germlings changed with growth phase. UV-B exposure from lamps reduced the activity of isozymes displaying catalase–peroxidase and glutathione reductase activities in 2575 more than in 324. The major effect of solar UV-A plus UV-B also was a reduction in catalase–peroxidases isozyme level, a finding confirmed by measurement of catalase specific activity. Impaired growth of M. anisopliae after near-UV exposure may be related to reduced abilities to handle oxidative stress.Key words: catalase–peroxidase, germination, glutathione reductase, Metarhizium anisopliae, near-UV, protein oxidation, superoxide dismutase.

scholarly journals Influence of Dietary Astaxanthin on the Hepatic Oxidative Stress Response Caused by Episodic Hyperoxia in Rainbow Trout

Antioxidants ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 626 ◽  
Author(s):  
Carmen Tatiana Kalinowski ◽  
Laurence Larroquet ◽  
Vincent Véron ◽  
Lidia Robaina ◽  
María Soledad Izquierdo ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Rainbow Trout ◽  
Glutathione Reductase ◽  
Plasma Glucose ◽  
Stress Responses ◽  
Physiological Stress ◽  
Mrna Level ◽  
Hepatic Glycogen ◽  
Antioxidant Enzyme Activities ◽  
Feeding Trial

A 13-week feeding trial was carried out with juvenile rainbow trout to test two diets: a control diet without astaxanthin (AX) supplementation (CTRL diet), and a diet supplemented with 100 mg/kg of synthetic AX (ASTA diet). During the last week of the feeding trial, fish were exposed to episodic hyperoxia challenge for 8 consecutive hours per day. Episodic hyperoxia induced physiological stress responses characterized by a significant increase in plasma cortisol and hepatic glycogen and a decrease in plasma glucose levels. The decrease of plasma glucose and the increase of hepatic glycogen content due to episodic hyperoxia were emphasized with the ASTA diet. Hyperoxia led to an increase in thiobarbituric acid-reactive substances in the muscle, diminished by dietary AX supplementation in both liver and muscle. Muscle and liver AX were increased and decreased respectively after 7-day episodic hyperoxia, leading to an increase in flesh redness. This augment of muscle AX could not be attributed to AX mobilization, since plasma AX was not affected by hyperoxia. Moreover, hyperoxia decreased most of antioxidant enzyme activities in liver, whereas dietary AX supplementation specifically increased glutathione reductase activity. A higher mRNA level of hepatic glutathione reductase, thioredoxin reductase, and glutamate-cysteine ligase in trout fed the ASTA diet suggests the role of AX in glutathione and thioredoxin recycling and in de novo glutathione synthesis. Indeed, dietary AX supplementation improved the ratio between reduced and oxidized glutathione (GSH/GSSG) in liver. In addition, the ASTA diet up-regulated glucokinase and glucose-6-phosphate dehydrogenase mRNA level in the liver, signaling that dietary AX supplementation may also stimulate the oxidative phase of the pentose phosphate pathway that produces NADPH, which provides reducing power that counteracts oxidative stress. The present results provide a broader understanding of the mechanisms by which dietary AX is involved in the reduction of oxidative status.

scholarly journals Contribution of Mn-Cofactored Superoxide Dismutase (SodA) to the Virulence of Streptococcus agalactiae

2001 ◽  
Vol 69 (8) ◽  
pp. 5098-5106 ◽  
Author(s):  
Claire Poyart ◽  
Elisabeth Pellegrini ◽  
Olivier Gaillot ◽  
Claire Boumaila ◽  
Marina Baptista ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Superoxide Dismutase ◽  
Streptococcus Agalactiae ◽  
Specific Activity ◽  
Infection Model ◽  
Mouse Bone Marrow ◽  
Group B Streptococci ◽  
Bacterial Killing ◽  
Cell Extracts

ABSTRACT Superoxide dismutases convert superoxide anions to molecular oxygen and hydrogen peroxide, which, in turn, is metabolized by catalases and/or peroxidases. These enzymes constitute one of the major defense mechanisms of cells against oxidative stress and hence play a role in the pathogenesis of certain bacteria. We previously demonstrated that group B streptococci (GBS) possess a single Mn-cofactored superoxide dismutase (SodA). To analyze the role of this enzyme in the pathogenicity of GBS, we constructed a sodA-disrupted mutant of Streptococcus agalactiae NEM316 by allelic exchange. This mutant was subsequently cis complemented by integration into the chromosome of pAT113/Sp harboring the wild-typesodA gene. The SOD specific activity detected by gel analysis in cell extracts confirmed that active SODs were present in the parental and complemented strains but absent in thesodA mutant. The growth rates of these strains in standing cultures were comparable, but the sodA mutant was extremely susceptible to the oxidative stress generated by addition of paraquat or hydrogen peroxide to the culture medium and exhibited a higher mutation frequency in the presence of rifampin. In mouse bone marrow-derived macrophages, the sodA mutant showed an increased susceptibility to bacterial killing by macrophages. In a mouse infection model, after intravenous injection the survival of thesodA mutant in the blood and the brain was markedly reduced in comparison to that of the parental and complemented strains whereas only minor effects on survival in the liver and the spleen were observed. These results suggest that SodA plays a role in GBS pathogenesis.

scholarly journals Nitric oxide, lipid peroxidation products, and antioxidants in primary fibromyalgia and correlation with disease severity

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Varsha Shukla ◽  
Siddharth Kumar Das ◽  
Abbas Ali Mahdi ◽  
Shweta Agarwal ◽  
Sukhanshi Khandpur
Keyword(s):  
Oxidative Stress ◽  
Nitric Oxide ◽  
Lipid Peroxidation ◽  
Superoxide Dismutase ◽  
Glutathione Peroxidase ◽  
Glutathione Reductase ◽  
Disease Severity ◽  
Pain Perception ◽  
High Plasma ◽  
Primary Fibromyalgia

Summary Background Fibromyalgia syndrome (FMS) is characterized by altered pain perception with chronic, widespread musculoskeletal pain. The relationship between nitric oxide, oxidative stress and the severity of FMS has not been studied. This study evaluated NO levels in plasma, LPO products and antioxidants in Red Cell lysate in patients of FMS and correlated it with disease severity. Methods 105 FMS patients who fulfilled 1990 ACR Criteria and 105 age- and sex-matched healthy controls were recruited over two years from 2013 to 2015. Antioxidative enzyme activity was assessed by the estimation of catalase, glutathione peroxidase (GPx) and glutathione reductase (GR) and superoxide dismutase (SOD). Nitric oxide in plasma, MDA marker of lipid peroxidation (LPO) in the lysate was donen for estimating oxidative stress. FIQR was used to assess the severity of fibromyalgia. Results The catalase, superoxide dismutase, glutathione reductase and glutathione peroxidase levels were significantly low in patients than controls (p<0.001). Plasma NO levels and LPO were also significantly high (p<0.05). NO and LPO levels showed a significant positive correlation with FIQR (r: 0.57, 0.8 and p: <0.001) whereas a negative correlation was observed between antioxidants (Cat, GR and GPx, but not SOD) and FIQR. Conclusions Low antioxidants and raised LPO in RBC lysate in patients with FM together with high plasma NO correlated with the severity of FMS.

Assessment of the effects of zinc on the growth and antioxidant enzymes in Scenedesmus ellipsoideus Chodat

2019 ◽  
Vol 48 (3) ◽  
pp. 270-278
Author(s):  
Hediye Elif Kiliç ◽  
Hatice Tunca ◽  
Tuğba Ongun Sevindik ◽  
Ali Doğru
Keyword(s):  
Oxidative Stress ◽  
Growth Rate ◽  
Superoxide Dismutase ◽  
Antioxidant Enzymes ◽  
Glutathione Reductase ◽  
Photosynthetic Pigments ◽  
Biomass Accumulation ◽  
Zn Toxicity ◽  
Zn Concentration ◽  
Total Superoxide Dismutase

Abstract This study explores the activity of total superoxide dismutase (SOD), ascorbate peroxidase (APX) and glutathione reductase (GR), biomass accumulation and chlorophyll a content in Scenedesmus ellipsoideus Chodat grown under conditions of varying zinc (Zn) concentrations. In addition, the activity of different SOD isozymes (MnSOD, FeSOD and CuZnSOD) was measured separately to determine the intracellular extent of oxidative stress resulting from Zn toxicity. We found that the activity of FeSOD and MnSOD was induced by lower Zn concentration (2 μg ml−1 and 4 μg ml−1, respectively), whereas CuZnSOD activity was not affected, which indicates that chloroplasts are the first location in S. ellipsoideus cells where superoxide accumulation is accelerated by Zn toxicity. The activity of total SOD and APX was significantly increased by moderate Zn concentrations, probably due to some oxidative stress caused by Zn toxicity. The higher level of Zn application, however, led not only to the inhibition of total SOD and APX activity, but also to the reduction of biomass accumulation and chlorophyll a content. As a result, it can be concluded that the accumulation of superoxide radicals and H2O2 in S. ellipsoideus cells induced by Zn toxicity may be responsible for the reduced growth rate and the impairment of photosynthetic pigments.

scholarly journals Colony sectorization of Metarhizium anisopliae is a sign of ageing

Microbiology ◽  
2005 ◽  
Vol 151 (10) ◽  
pp. 3223-3236 ◽  
Author(s):  
Chengshu Wang ◽  
Tariq M. Butt ◽  
Raymond J. St Leger
Keyword(s):  
Oxidative Stress ◽  
Differentially Expressed Genes ◽  
Microarray Analysis ◽  
Stress Responses ◽  
Metarhizium Anisopliae ◽  
Cell Metabolism ◽  
Cell Structure ◽  
Pathogenic Fungus ◽  
Differentially Expressed ◽  
Physiological Adaptation

Spontaneous phenotypic degeneration resulting in sterile sectors is frequently observed when culturing filamentous fungi on artificial medium. Sterile sectors from two different strains of the insect pathogenic fungus Metarhizium anisopliae were investigated and found to contain reduced levels of cAMP and destruxins (insecticidal peptides). Microarray analysis using slides printed with 1730 clones showed that compared to wild-type, sterile sectors down-regulated 759 genes and upregulated 27 genes during growth in Sabouraud glucose broth or on insect cuticle. The differentially expressed genes are largely involved in cell metabolism (18·8 %), cell structure and function (13·6 %) and protein metabolism (8·8 %). Strong oxidative stress was demonstrated in sectorial cultures using the nitro blue tetrazolium assay and these cultures show other syndromes associated with ageing, including mitochondrial DNA alterations. However, genes involved in deoxidation and self-protection (e.g. heat-shock proteins, HSPs) were also upregulated. Further evidence of physiological adaptation by the degenerative sectorial cultures included cell-structure reorganization and the employment of additional signalling pathways. In spite of their very similar appearance, microarray analysis identified 181 genes differentially expressed between the two sectors, and the addition of exogenous cAMP only restored conidiation in one of them. Most of the differentially expressed genes were involved in catabolic or anabolic pathways, but the latter included genes for sporulation. Compared to the mammalian ageing process, sectorization in M. anisopliae showed many similarities, including similar patterns of cAMP production, oxidative stress responses and the involvement of HSPs. Thus, a common molecular machinery for ageing may exist throughout the eukaryotes.

Role of oxidative stress and thiol antioxidant enzymes in nickel toxicity and resistance in strains of the green alga Scenedesmus acutus f. alternans

2001 ◽  
Vol 47 (11) ◽  
pp. 987-993 ◽  
Author(s):  
Varinder K Randhawa ◽  
Fengzhen Zhou ◽  
Xiaolei Jin ◽  
Czesia Nalewajko ◽  
Donn J Kushner
Keyword(s):  
Reactive Oxygen Species ◽  
Superoxide Dismutase ◽  
Glutathione Peroxidase ◽  
Glutathione Reductase ◽  
Resistant Strain ◽  
Sensitive Strain ◽  
The Other ◽  
Oxygen Species ◽  
Scenedesmus Acutus ◽  
Glucose 6 Phosphate Dehydrogenase

Treatment with Ni(NO3)2 leads to the formation of reactive oxygen species (ROS) in the green alga Scenedesmus acutus f. alternans, causing lipid peroxidation. This effect was stronger in a Ni-sensitive strain, UTEX72, than in a Ni-resistant strain, B4. In the resistant strain, Ni induced an increased ratio of reduced to oxidized glutathione (GSH:GSSG), whereas it caused a lowered ratio in the sensitive strain. Enzymes involved in the control of ROS were studied in these strains as well as two others that have shown different degrees of nickel resistance. The resistant strain, B4, which grows while containing large amounts of internal Ni, had much higher levels of glutathione reductase and catalase than the other strains. The sensitive strain, UTEX72, had higher levels of glutathione peroxidase, superoxide dismutase, and glucose-6-phosphate dehydrogenase than did strain B4. The resistant strains, Ni-Tol and Cu-Tol, derived from strain UTEX72, which are partly able to exclude Ni, had enzyme profiles that resembled that of UTEX72 more closely than that of B4. Treatment with 10 and 100 µM Ni for 4 or 22 h had complex effects on enzyme levels in all four strains. Ni decreased glutathione reductase in B4, slightly increased it in Ni-Tol and Cu-Tol, and did not affect the low levels of this enzyme in UTEX72. Ni lowered glutathione peroxidase in B4 and either did not affect it or slightly raised it in the other strains. Ni lowered catalase in B4 and did not affect the other strains. Superoxide dismutase was raised in B4 and Ni-Tol and lowered in Cu-Tol and UTEX72, and glucose-6-phosphate dehydrogenase was lowered in all four strains. These results suggest that one major mechanism of Ni resistance, especially in strain B4, may be the ability to combat the formation of ROS when exposed to this metal, likely by maintaining a high GSH:GSSG ratio.Key words: Scenedesmus acutus f. alternans, glutathione reductase, glutathione peroxidase, catalase, superoxide dismutase, glucose-6-phosphate dehydrogenase, lipid peroxidation, nickel, reactive oxygen species.

Oxidative stress response of Mycosphaerella fijiensis, the causal agent of black leaf streak disease in banana plants, to hydrogen peroxide and paraquat

2009 ◽  
Vol 55 (7) ◽  
pp. 887-894 ◽  
Author(s):  
Miguel J. Beltrán-García ◽  
Gilberto Manzo-Sanchez ◽  
Salvador Guzmán-González ◽  
Carlos Arias-Castro ◽  
Martha Rodríguez-Mendiola ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Stress Responses ◽  
Antioxidant Response ◽  
Mycosphaerella Fijiensis ◽  
Native Page ◽  
Rapid Decomposition ◽  
Black Leaf Streak ◽  
Catalase Peroxidase ◽  
Black Leaf Streak Disease

Mycosphaerella fijiensis causes black leaf streak disease in banana and plantain. This fungus is usually attacked by reactive oxygen species secreted by the plant or during exposure to fungicide, however, little is known about the antioxidant response of the fungus. In this study, mycelia were observed to totally decompose 30 mmol/L of hydrogen peroxide (H2O2) within 120 min, liberating oxygen bubbles, and also to survive in concentrations as high as 100 mmol/L H2O2. The oxidative stress responses to H2O2, paraquat, and hydroquinone were characterized in terms of the activities of catalase and superoxide dismutase (SOD). Two active catalase bands were seen in native PAGE induced by H2O2. Band I had monofunctional activity and band II had bifunctional catalase–peroxidase activity. Two isozymes of SOD, distinguishable by their cyanide sensitivity, were found; CuZnSOD was the main one. The combination of H2O2 and 3-aminotriazole reduced the accumulation of biomass up to 40% compared with exposure to H2O2 alone, suggesting that catalase is important for the rapid decomposition of H2O2 and has a direct bearing on cell viability. The results also suggest that the superoxide anion formed through the redox of paraquat and hydroquinone has a greater effect than H2O2 on the cellular viability of M. fijiensis.

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