scholarly journals Use of Ore-Derived Humic Acids With Diverse Chemistries to Elucidate Structure-Activity Relationships (SAR) of Humic Acids in Plant Phenotypic Expression

2021 ◽  
Vol 12 ◽  
Author(s):  
Richard T. Lamar ◽  
Hiarhi Monda ◽  
Rachel Sleighter
Keyword(s):  
Stress Response ◽  
Humic Acids ◽  
Plant Biomass ◽  
Electron Flow ◽  
Phenotypic Expression ◽  
Radical Scavenging ◽  
Morphological Characteristics ◽  
Membrane Depolarization ◽  
Ros Production ◽  
Structure Activity

We report the results of a structure-activity relationship study that was undertaken to identify humic substance chemistries that drive the plant biostimulant response. The effects of seven extensively chemically characterized, ore-derived humic acids (HA) on corn seedling biomass and root and shoot morphological parameters were investigated. Chemometric analyses were then conducted to identify correlations between HA chemical features and plant biomass and morphological characteristics. The primary chemical driver of plant biomass and morphology was the ratio between HA electron accepting capacity (EAC) and electron donating capacity (EDC). The HA electron accepting capacity is found in quinones and semiquinone free radicals, while the HA electron donating capacity is found in polyphenolics and glycosylated polyphenolics. Based on our results, we propose a mechanism of action for ore-derived HA plant biostimulation that involves the interplay of pro-oxidants, in the form of quinones and semiquinone radicals, and antioxidants, in the form of polyphenols and possibly glycones and carbohydrates. The quinones/semiquinones initiate an oxidative stress response via the stimulation of transmembrane electron flow that results in both reactive oxygen species (ROS) production (i.e., an oxidative burst) and membrane depolarization, the latter of which allows Ca2+ flux from the apoplast into the cytoplasm. Based on the magnitude of depolarization, a specific cytoplasmic Ca2+ signature is produced. As a secondary messenger Ca2+, via binding to Ca2+− sensor proteins, transmits the signature signal, resulting in specific intracellular responses that include changes to plant morphology. The greater the EAC, the greater the ROS production and magnitude of plasma membrane depolarization and resulting stress response. The HA antioxidants are able to scavenge and quench the ROS and thus modulate the intensity and extent of the stress response to greater or lesser degrees, based on their concentrations and radical scavenging efficiencies, and thus modify the Ca2+ signature and ultimately the intracellular molecular responses.

scholarly journals Humic acids trigger the weak acids stress response in maize seedlings

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Daiane Carvalho Baía ◽  
Fábio L. Olivares ◽  
Daniel B. Zandonadi ◽  
Cleiton de Paula Soares ◽  
Riccardo Spaccini ◽  
...  
Keyword(s):  
Abiotic Stress ◽  
Stress Response ◽  
Intracellular Ph ◽  
Humic Acids ◽  
Abiotic Stress Tolerance ◽  
Molecular Response ◽  
Maize Seedlings ◽  
Weak Acids ◽  
Acetoxymethyl Ester ◽  
Chemical Priming

Abstract Background Plants primed by humic acids showed physiological and molecular response against different abiotic stresses without the presence of stressor agents (salinity, drought, heavy metal toxicity). It is plausible that humic acids themselves can act as chemical priming substances in plants. We hypothesized that humic acids can trigger the weak acids stress response in cell plants acidifying the cytosol and thus eliciting the transduction signalling response cascade. Methods The dose–response curves of maize seedlings roots with different concentrations of humic, acetic and salicylic acids determined the most active and inhibitory concentration. These data were further used to evaluate changes on intracellular pH using BCECF-AM probe (2,7-bis(2-carboxyethyl)-5(and 6)-carboxyfluorescein, acetoxymethyl ester) and differential transcription level of genes related to weak stress response in plants by qPCR real time. Results Humic acids like short chain organic acids decrease the intracellular pH showed by the increased fluorescence of BCECF probe. The drop in cytosolic pH promoted by humic acids was not transient. We observed a high level of protein kinases related to cell energy-sensing and transcription factors associated to transduction of stress signalling. Conclusion The humic acids can be considered as a chemical priming agent, since in the appropriate concentration they can induce the typical plant abiotic stress response of weak acids inducing plant acclimation and enhancing the abiotic stress tolerance.

scholarly journals Antioxidant, Cytotoxic, Genotoxic, and DNA-Protective Potential of 2,3-Substituted Quinazolinones: Structure—Activity Relationship Study

2021 ◽  
Vol 22 (2) ◽  
pp. 610
Author(s):  
Jana Hricovíniová ◽  
Zuzana Hricovíniová ◽  
Katarína Kozics
Keyword(s):  
Radical Scavenging ◽  
Reducing Power ◽  
Structure Activity Relationship ◽  
Dna Lesions ◽  
Activity Relationship ◽  
Antioxidant Compounds ◽  
Substitution Pattern ◽  
Structure Activity ◽  
Pharmacologically Active ◽  
Th 1

The evaluation of antioxidant compounds that counteract the mutagenic effects caused by the direct action of reactive oxygen species on DNA molecule is of considerable interest. Therefore, a series of 2,3-substituted quinazolinone derivatives (Q1–Q8) were investigated by different assays, and the relationship between their biological properties and chemical structure was examined. Genotoxicity and the potential DNA-protective effects of Q1–Q8 were evaluated by comet assay and DNA topology assay. Antioxidant activity was examined by DPPH-radical-scavenging, reducing-power, and total antioxidant status (TAS) assays. The cytotoxic effect of compounds was assessed in human renal epithelial cells (TH-1) and renal carcinoma cells (Caki-1) by MTT assay. Analysis of the structure–activity relationship disclosed significant differences in the activity depending on the substitution pattern. Derivatives Q5–Q8, bearing electron-donating moieties, were the most potent members of this series. Compounds were not genotoxic and considerably decreased the levels of DNA lesions induced by oxidants (H2O2, Fe2+ ions). Furthermore, compounds exhibited higher cytotoxicity in Caki-1 compared to that in TH-1 cells. Substantial antioxidant effect and DNA-protectivity along with the absence of genotoxicity suggested that the studied quinazolinones might represent potential model structures for the development of pharmacologically active agents.

Radical Scavenging Efficiency of Flavonoids Increased by Calcium(II) Binding: Structure‐Activity Relationship

2021 ◽  
Vol 6 (32) ◽  
pp. 8462-8470
Author(s):  
Chao Liu ◽  
Wen‐Zhu Wang ◽  
Meng‐Ting Song ◽  
Yao Lu ◽  
Ling‐Ling Qian ◽  
...  
Keyword(s):  
Radical Scavenging ◽  
Structure Activity Relationship ◽  
Activity Relationship ◽  
Structure Activity ◽  
Scavenging Efficiency ◽  
Binding Structure

Mitochondrial (‘mild’) uncoupling and ROS production: physiologically relevant or not?

2011 ◽  
Vol 39 (5) ◽  
pp. 1305-1309 ◽  
Author(s):  
Irina G. Shabalina ◽  
Jan Nedergaard
Keyword(s):  
Membrane Potential ◽  
Oxidative Damage ◽  
Uncoupling Protein ◽  
Electron Flow ◽  
Ros Production ◽  
Present Evidence ◽  
Beneficial Effects ◽  
Reverse Electron Flow ◽  
Species Production ◽  
Mild Uncoupling

During the last decade, the possibility that ‘mild’ uncoupling could be protective against oxidative damage by diminishing ROS (reactive oxygen species) production has attracted much interest. In the present paper, we briefly examine the evidence for this possibility. It is only ROS production from succinate under reverse electron-flow conditions that is sensitive to membrane potential fluctuations, and so only this type of ROS production could be affected; however, the conditions under which succinate-supported ROS production is observed include succinate concentrations that are supraphysiological. Any decrease in membrane potential, even ‘mild uncoupling’, must necessarily lead to large increases in respiration, i.e. it must be markedly thermogenic. Mitochondria within cells are normally ATP-producing and thus already have a diminished membrane potential, and treatment of cells, organs or animals with small amounts of artificial uncoupler does not seem to have beneficial effects that are explainable via reduced ROS production. Although it has been suggested that members of the uncoupling protein family (UCP1, UCP2 and UCP3) may mediate a mild uncoupling, present evidence does not unequivocally support such an effect, e.g. the absence of the truly uncoupling protein UCP1 is not associated with increased oxidative damage. Thus present evidence does not support mild uncoupling as a physiologically relevant alleviator of oxidative damage.

scholarly journals Transient Receptor Potential Melastatin 2 Negatively Regulates LPS-ATP-Induced Caspase-1-Dependent Pyroptosis of Bone Marrow-Derived Macrophage by Modulating ROS Production

2017 ◽  
Vol 2017 ◽  
pp. 1-8
Author(s):  
Haihong Wang ◽  
Xinyi Zhou ◽  
Hui Li ◽  
Xiaowei Qian ◽  
Yan Wang ◽  
...  
Keyword(s):  
Transient Receptor Potential ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Critical Role ◽  
Morphological Characteristics ◽  
Receptor Potential ◽  
Ros Production ◽  
Caspase 1 ◽  
Transient Receptor Potential Melastatin ◽  
Transient Receptor

Background. Pyroptosis, a new form of cell death, which has special morphological characteristics, depends on caspase-1 activation and occupies an important role in inflammatory immune diseases and ischemia-reperfusion injury. ROS is a common activator of NLR/caspase-1. Transient receptor potential melastatin 2 (TRPM2), a selective cation channel, is involved in inflammatory regulation. This study was designed to explore the role of TRPM2 in activating caspase-1 and caspase-1-dependent pyroptosis of mouse BMDMs. Methods. BMDMs isolated from WT and TRPM2−/− mice were treated with LPS and ATP, along with ROS inhibitor (NAC and DPI), caspase-1 inhibitor (Z-YVAD), or not. The activation of caspase-1 was measured by western blot. EtBr and EthD-2 staining were used to assess the incidence of pyroptosis. Results. Compared with WT, the activated caspase-1-P10 was higher and the percentage of EtBr positive cells was also increased in TRPM2−/− group, which were both inhibited by Z-YVAD, NAC, or DPI. ASC oligomerization was increased in TRPM2−/− group. Conclusion. Deletion of TRPM2 can enhance the activation of caspase-1 and pyroptosis, which may be via modulating ROS production, suggesting that TRPM2 plays a critical role in immune adjustment.

Trichomonas Vaginalis Induces Apoptosis via ROS and ER Stress Through ER-mitochondria Crosstalk in Human Cervical Epithelial Cells

2021 ◽  
Author(s):  
Fei Fei Gao ◽  
Juan-Hua Quan ◽  
Min A Lee ◽  
Wei Ye ◽  
Jae-Min Yuk ◽  
...  
Keyword(s):  
Stress Response ◽  
Epithelial Cells ◽  
Er Stress ◽  
Mitochondrial Dysfunction ◽  
Parasite Burden ◽  
Dependent Manner ◽  
Ros Production ◽  
Er Stress Response ◽  
Siha Cells ◽  
Mitochondrial Ros

Abstract Background: Human trichomoniasis is one of the most common sexually transmitted infections; however, its pathogenesis remains unclear. Here, we investigated the role of the endoplasmic reticulum (ER) in apoptosis induction by T. vaginalis in human cervical epithelial SiHa cellsMethods: We evaluated the cytotoxicity, apoptosis, reactive oxygen species (ROS) production, mitochondrial membrane potential (MMP), ER stress response, and Bcl-2 family protein expressions using LDH assay, immunocytochemistry, flow cytometry, JC-1 dye staining, and western blotting.Results: T. vaginalis induced LDH-dependent cytotoxicity, mitochondrial ROS production, and apoptosis in SiHa cells, parasite burden- and infection time-dependently. T. vaginalis also induced ER stress response and mitochondrial dysfunction, such as MMP depolarization and imbalance in levels of Bcl-2 family proteins, in SiHa cells in a parasite burden- and infection time-dependent manner. Pretreatment with N-Acetyl cysteine (ROS scavenger) or 4-phenylbutyric acid (4-PBA, ER stress inhibitor) significantly alleviated apoptosis, ROS production, mitochondrial dysfunction, and ER stress response in a dose-dependent manner. These data suggested that SiHa cell apoptosis is affected by ROS and ER stress after T. gondii infection. In addition, T. vaginalis induced ASK1 and JNK phosphorylation in SiHa cells, however 4-PBA or SP600125 (JNK inhibitor) pretreatment significantly attenuated ASK1/JNK phosphorylation, mitochondrial dysfunction, apoptosis, and ER stress response in SiHa cells, dose-dependently.Conclusions: T. vaginalis induces mitochondrial apoptosis via ROS and parasite-mediated ER stress via the IRE1/ASK1/JNK/Mcl-1 pathways, and also induces ER stress response directly and mitochondrial ROS-dependently in human cervical epithelial SiHa cells, thus, T. vaginalis induces apoptosis via ROS and ER stress through ER-mitochondria crosstalk in human cervical epithelial cells. These results expand our understanding of the molecular mechanisms underlying the pathogenesis of human trichomoniasis.

Mitigating Stress Response to Optimize Human Performance

2019 ◽  
pp. 184-199
Author(s):  
James Ness ◽  
Josephine Q. Wojciechowski
Keyword(s):  
Stress Response ◽  
Human Performance ◽  
Phenotypic Expression ◽  
Wild Type ◽  
Health Consequences

Optimizing human performance is the expression of a desired phenotype to meet the challenges of a particular task. Desired phenotypes are expressed in response to canalizing experiences such as in acclimatization to environments. Here one’s biobehavioral system adapts to the challenges of the environment to reduce physiologic strain on the system. These adaptations are within the biobehavioral system’s repertoire of expressible phenotypes and are reversible. Desired phenotypes can be maintained, facilitated, or induced by canalizing experiences. In the desire to optimize performance, the canalizing experiences are often designed to induce or prolong phenotypic expression to meet the demands of a constructed task. In these cases, the canalizing experiences, whether pharmacological or other physiologically invasive, often lead to irreversible negative health consequences. This chapter discusses the effects of canalizing experiences in terms of the strains on the biobehavioral system. The chapter advances a concept of strong environment as a means to facilitate and maintain phenotypes, which are within the phenotypic expressible repertoire. The argument is made that leveraging the bio-behavioral system’s wild type rather than domesticating the system to express a supernormal phenotype yields greater agility and overall health in a population to overcome challenges.

scholarly journals Antioxidant Activity of 1’-Hydroxyethylnaphthazarins and their Derivatives

2017 ◽  
Vol 12 (12) ◽  
pp. 1934578X1701201
Author(s):  
Natalia K. Utkina ◽  
Natalia D. Pokhilo
Keyword(s):  
Antioxidant Activity ◽  
Radical Cation ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Structure Activity Relationship ◽  
Activity Relationship ◽  
Hydroxyl Group ◽  
Side Chains ◽  
Scavenging Activity ◽  
Structure Activity

The ABTS•+ radical cation scavenging activity of known (2-5, 9, 10) and new (6-8) 1’-hydroxyethylnaphthazarins and their products of esterification and etherification was evaluated and a structure-activity relationship was studied. It was shown, that the structure of side chains does not affect the radical scavenging activity of 1’-hydroxyethylnaphthazarins and their derivatives. The presence of methoxyl groups on the naphthazarin core slightly enhanced the antioxidant activity of compounds compared with compounds without methoxyl groups. The presence of the additional hydroxyl group on the naphthazarin moiety of isonorlomazarin (5) and its derivative (6) is essential for the activity.

scholarly journals DPPH-Scavenging Activities and Structure-Activity Relationships of Phenolic Compounds

2010 ◽  
Vol 5 (11) ◽  
pp. 1934578X1000501 ◽  
Author(s):  
Cheng-Dong Zheng ◽  
Gang Li ◽  
Hu-Qiang Li ◽  
Xiao-Jing Xu ◽  
Jin-Ming Gao ◽  
...  
Keyword(s):  
Phenolic Compounds ◽  
Antiradical Activity ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Basic Structure ◽  
Hydroxyl Group ◽  
Structure Activity Relationships ◽  
Structure Activity ◽  
Dpph Scavenging ◽  
Dpph Radical Scavenging

Thirty-eight phenolic compounds (including 31 flavonoids) were examined for their DPPH radical-scavenging activities, and structure-activity relationships were evaluated. Specifically, the presence of an Ortho-dihydroxyl structure in phenolics is largely responsible for their excellent antiradical activity. 3-Hydroxyl was also essential to generate a high radical-scavenging activity. An increasing number of hydroxyls on flavones with a 3′,4′-dihydroxyl basic structure, the presence of a third hydroxyl group at C-5′, a phloroglucinol structure, glycosylation and methylation of the hydroxyls, and some other hydroxyls, for example 5-, and 7-hydroxyl in ring A, decreased the radical-scavenging activities of flavonoids and other phenolics.

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