scholarly journals PP2A Methylation is Necessary for Broad Stress Tolerance

2021 ◽  
Author(s):  
Maria T. Creighton ◽  
Dugassa Nemie-Feyissa ◽  
Nabeela Zaman ◽  
Sverre S. Johansen ◽  
Hege Dysjaland ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Stress Tolerance ◽  
Dry Weight ◽  
Sodium Concentration ◽  
Post Translational Modification ◽  
Iron Starvation ◽  
Methyl Transferase ◽  
High Concentrations ◽  
Fe Homeostasis ◽  
Rock Wool

Abstract Background: LEUCINE CARBOXYL METHYL TRANSFERASE 1 (LCMT1) transfers a methyl group from the methyl donor S-adenosylmethionine (SAM) to the catalytic subunit of PROTEIN PHOSPHATASE 2A (PP2A). This post-translational modification of PP2A is manifested throughout eukaryotes from yeast to plants and animals. Although highly conserved, the importance of the methylation is poorly understood. Since Arabidopsis plants with knocked out LCMT1 grow and develop fairly normally, we decided to search for conditions that may reveal the benefits of this regulation. We compared the effects of various stressful conditions on Arabidopsis wild type (WT) and a lcmt1 mutant possessing only non-methylated PP2A. Results: Seedlings were grown in Petri dishes for 5-12 days, or in rock wool and soil for up to 7 weeks. A significant increase in sodium concentration was found for lcmt1 relative to WT, but this was not linked with stressful conditions. Plants were exposed to variable levels of the chelator EDTA, iron, zinc, aluminium, heat, and hydrogen peroxide. The lcmt1 mutant was clearly more sensitive than WT to all the various stresses, as demonstrated by effects on seedling root growth and on shoots of rosette stage plants on rock wool. When omitting EDTA, expression of genes known as signature genes for iron deficiency, FIT1, bHLH100, IMA1, IRT1 was strongly enhanced in lcmt1. Although an iron starvation response was induced, Fe homeostasis was apparently maintained by slowed growth in lcmt1 and the Fe level related to tissue dry weight was not changed. Among genes induced in lcmt1 were also the Zn induced gene ZIF1, and heat shock protein HSP90-1. Concentrations of non-iron transition metals, Cu, Mn and Zn, increased significantly in response to lack of EDTA for both lcmt1 and WT tissue, and especially the growth of lcmt1 was strongly hampered. Conclusions: Presence of the LCMT1 gene was necessary to cope efficiently with an imbalance in the micronutrients, heat stress, and oxidative stress. Methylation of PP2A appears important to ameliorate the toxic effects of metals present in unfavourable high concentrations as well as heat or oxidative stress. The experiments establish LCMT1 as a key component in broad stress tolerance.

Potential Contribution of Nutrients and Polycyclic Aromatic Hydrocarbons from the Creeks of Cootes Paradise Marsh

1996 ◽  
Vol 31 (3) ◽  
pp. 485-504 ◽  
Author(s):  
Patricia Chow-Fraser ◽  
Barb Crosbie ◽  
Douglas Bryant ◽  
Brian McCarry
Keyword(s):  
Aromatic Hydrocarbons ◽  
Laboratory Experiments ◽  
Dry Weight ◽  
Common Source ◽  
Potential Contribution ◽  
Nitrogen And Phosphorus ◽  
Engine Combustion ◽  
Polycyclic Aromatic ◽  
High Concentrations ◽  
Derivatives Of

Abstract During the summer of 1994, we compared the physical and nutrient characteristics of the three main tributaries of Cootes Paradise: Spencer, Chedoke and Borer’s creeks. On all sampling occasions, concentrations of CHL α and nutrients were always lowest in Borer’s Creek and highest in Chedoke Creek. There were generally 10-fold higher CHL α concentrations and 2 to 10 times higher levels of nitrogen and phosphorus in Chedoke Creek compared with Spencer Creek. Despite this, the light environment did not differ significantly between Spencer and Chedoke creeks because the low algal biomass in Spencer Creek was balanced by a relatively high loading of inorganic sediments from the watershed. Laboratory experiments indicated that sediments from Chedoke Creek released up to 10 µg/g of soluble phosphorus per gram (dry weight) of sediment, compared with only 2 µg/g from Spencer Creek. By contrast, sediment samples from Spencer Creek contained levels of polycyclic aromatic hydrocarbon that were as high as or higher than those from Chedoke Creek, and much higher than those found in Borer’s Creek. The distribution of normalized PAH concentrations suggests a common source of PAHs in all three tributaries, most likely automobile exhaust, since there were high concentrations of fluoranthene and pyrene, both of which are derivatives of engine combustion.

scholarly journals Electroanalytical Techniques for the Detection of Selenium as a Biologically and Environmentally Significant Analyte—A Short Review

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1768
Author(s):  
Miroslav Rievaj ◽  
Eva Culková ◽  
Damiána Šandorová ◽  
Zuzana Lukáčová-Chomisteková ◽  
Renata Bellová ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Essential Element ◽  
Analytical Techniques ◽  
High Sensitivity ◽  
Stripping Voltammetry ◽  
Short Review ◽  
Electroanalytical Methods ◽  
High Concentrations ◽  
Speed Of Analysis

This short review deals with the properties and significance of the determination of selenium, which is in trace amounts an essential element for animals and humans, but toxic at high concentrations. It may cause oxidative stress in cells, which leads to the chronic disease called selenosis. Several analytical techniques have been developed for its detection, but electroanalytical methods are advantageous due to simple sample preparation, speed of analysis and high sensitivity of measurements, especially in the case of stripping voltammetry very low detection limits even in picomoles per liter can be reached. A variety of working electrodes based on mercury, carbon, silver, platinum and gold materials were applied to the analysis of selenium in various samples. Only selenium in oxidation state + IV is electroactive therefore the most of voltammetric determinations are devoted to it. However, it is possible to detect also other forms of selenium by indirect electrochemistry approach.

scholarly journals Oxygen Is Instrumental for Biological Signaling: An Overview

Oxygen ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 3-15
Author(s):  
John T. Hancock
Keyword(s):  
Oxidative Stress ◽  
Superoxide Anion ◽  
Nitrosative Stress ◽  
Redox Status ◽  
Complex Interplay ◽  
Wide Range ◽  
Form Part ◽  
High Concentrations ◽  
And Control ◽  
Signaling Components

Control of cellular function is extremely complex, being reliant on a wide range of components. Several of these are small oxygen-based molecules. Although reactive compounds containing oxygen are usually harmful to cells when accumulated to relatively high concentrations, they are also instrumental in the control of the activity of a myriad of proteins, and control both the upregulation and downregulation of gene expression. The formation of one oxygen-based molecule, such as the superoxide anion, can lead to a cascade of downstream generation of others, such as hydrogen peroxide (H2O2) and the hydroxyl radical (∙OH), each with their own reactivity and effect. Nitrogen-based signaling molecules also contain oxygen, and include nitric oxide (NO) and peroxynitrite, both instrumental among the suite of cell signaling components. These molecules do not act alone, but form part of a complex interplay of reactions, including with several sulfur-based compounds, such as glutathione and hydrogen sulfide (H2S). Overaccumulation of oxygen-based reactive compounds may alter the redox status of the cell and lead to programmed cell death, in processes referred to as oxidative stress, or nitrosative stress (for nitrogen-based molecules). Here, an overview of the main oxygen-based molecules involved, and the ramifications of their production, is given.

Role of manganese in protection against oxidative stress under iron starvation in cyanobacteriumAnabaena7120

2015 ◽  
Vol 55 (6) ◽  
pp. 729-740 ◽  
Author(s):  
Manish Singh Kaushik ◽  
Meenakshi Srivastava ◽  
Ekta Verma ◽  
Arun Kumar Mishra
Keyword(s):  
Oxidative Stress ◽  
Iron Starvation

scholarly journals Hydrogen peroxide priming modulates abiotic oxidative stress tolerance: insights from ROS detoxification and scavenging

2015 ◽  
Vol 6 ◽  
Author(s):  
Mohammad A. Hossain ◽  
Soumen Bhattacharjee ◽  
Saed-Moucheshi Armin ◽  
Pingping Qian ◽  
Wang Xin ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Stress Tolerance ◽  
Oxidative Stress Tolerance

scholarly journals Temporal and spatial variation on heavy metal concentrations in the oyster Ostrea equestris on the northern coast of Rio de Janeiro State, Brazil

2005 ◽  
Vol 65 (1) ◽  
pp. 67-76 ◽  
Author(s):  
A. G Ferreira ◽  
A. L. S. Machado ◽  
I. R. Zalmon
Keyword(s):  
Heavy Metal ◽  
Spatial Variation ◽  
Rio De Janeiro ◽  
Dry Weight ◽  
Temporal Variations ◽  
Average Concentration ◽  
Northern Coast ◽  
High Concentrations ◽  
Janeiro State ◽  
Ostrea Equestris

Heavy metal (Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) concentrations were determined by ICP-AES in Ostrea equestris from three beaches (Barra do Furado, Buena, and Ponta do Retiro) on the northern coast of Rio de Janeiro State. The average concentration was 0.8 ± 0.18, 0.4 ± 0.21, 58 ± 25.6, 249 ± 52.3, 11 ± 1.31, 0.55 ± 0.16, 0.13 ± 0.11, and 1131 ± 321 µg.g-1 dry weight for Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn respectively. Significant spatial variation (p < 0.05) between the samples areas occurred for Cr, Pb, and Zn with higher values in Barra do Furado; and for Cu in Ponta do Retiro. Significant temporal variations (p < 0.05) were observed for all metals except Cu. Temporal variability may be related to changes in the inputs of metals associated with suspended particles. Concentrations were similar to those found in areas under low pollution impact, except for Zn, the high concentrations of which probably reflect the physiological characteristics of these organisms.

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