Non-enzymatic Systems Research Articles

Exogenous spermidine enhances the photosynthetic and antioxidant capacity of citrus seedlings under high temperature

ABSTRACT Studies have not fully explained the underlying mechanism of spermidine-mediated heat tolerance. This study investigated the possible role of spermidine (Spd) in regulating citrus heat tolerance. The results showed that exogenous Spd effectively alleviated the limitation of high temperature (HT) on photosynthesis. Exogenous Spd increased the chlorophyll content, net photosynthetic rate, intercellular carbon dioxide concentration, stomatal conductance, maximum and effective quantum yield of PSII photochemistry, nonphotochemical quenching coefficient, and electron transport rate in citrus seedlings under HT stress, but declined the stomatal limitation value. In addition, Spd treatment promoted the dynamic balance of the citrus enzymatic and non-enzymatic antioxidants system. Spd application significantly increased the activity of superoxide dismutase, peroxidase, catalase, ascorbic acid, and glutathione and the expression level of corresponding genes at high temperature, while reducing the content of H2O2 and malondialdehyde. Therefore, our findings suggested exogenous Spd significantly ameliorated citrus physiological and photosynthetic adaptation under HT stress, thereby providing helpful guidance for citrus cultivation in HT events.

Biochemical markers of environmental stress tolerance in finger millet [Eleusine coracana (L.) Gaertn.] germplasm of Central Himalayan Region

Availability of the germplasm of suitable crops for cultivation in environmental stress prone and resource poor terrains is crucial for food security in these regions. Rich diversity of millets, which are highly tolerant to extreme weather conditions, is obtainable in the Central Himalayan Region (CHR). However, biochemical evaluation of available germplasm for food security is a major apprehension yet to be addressed properly. In this backdrop expeditions were conducted to tap and evaluate the germplasm variability of finger millet [Eleusine coracana (L.) Gaertn.]. Germplasm accessions (314) having traits of agronomic importance were collected and evaluated for three consecutive years. In addition to set of biochemical traits, yield was recorded to find out suitable germplasm for large scale cultivation/breeding programme. At flowering stage variability in antioxidants level of leaves such as glutathione and ascorbate ranged from 105.27 to 423.63 mmol g−1 FW and 4.89–10.21 mmol g−1 FW respectively. Extensive variableness in the activity of enzymes which are important for multiple abiotic stress tolerance viz., catalase (115–855 mmol H2O2 decomposed min−1 mg−1 protein), peroxidase (1.24–6.35 mmol substrate min−1 mg−1 protein), superoxide dismutase (1236–2963 enzyme U mg−1 protein), glutathione reductase (0.53–2.14 mmol substrate min−1 mg−1 protein), ascorbate peroxidase (1.86–7.04 mmol substrate min−1 mg−1 protein), monodehydroascorbate reducatase (1.11–4.41 mmol substrate min−1 mg−1 protein), dehydroascorbate reducatase (0.34–1.36 mmol substrate min−1 mg−1 protein) was also recorded. Worldwide Abiotic/environmental stresses hamper agricultural production. Enzymatic and non-enzymatic defence system precisely controls this situation. Hence, biochemical evaluation might be an appropriate strategy for identification of suitable germplam to combat the problem of food security in such areas.

Complex study of Cancer Morbidity and Inflammatory Markers, Presented in the Blood Serum of the Rural Population of Sachkhere District of Georgia.

Aim:The purpose of the study was to compare the morbidity from cancer (expressed as incidence) to the average levels of blood serum inflammatory markers in the population of the Sachkhere region (Georgia).Methods:healthy residents of the Sachkhere district were examined. In the blood serum samples of patients, the cytokines (IL-1α, IL-10, TGF-β, IL-12, IL-17, TNF-α, IL-6) and NOx content, as well as the total antioxidant activity of the non-enzymatic system (TAA) were determined; using light microscopy, buccal micronuclei (MnB) of epithelial cells of the oral mucosa, as indicators of chromosomal disorders, were studied. Results:Study results show, that cancer incidence in Sareki was statistically significantly higher as in Chorvila and Sairkhe (p=0.002; p=0.004); in Sareki inhabitant’s blood serum levels of the IL-6, NO are increased (p=0.004, p=0.05), and IL-17, TGFβ, and IL-10 levels are decreased (p=0.010, p=0.001, p=0.033) in comparison to data in Chorvila; in Chorvila inhabitants’ indicators of TAA of blood serum and MnB of epithelium cell levels were lower (p=0.001,p=0.045) then in Sairkhe and Sareki. Conclusion:The existence of statistically reliable associations between the levels of cancer incidence in the populations of the surveyed villages and the indicators of immune and oxidative status in their virtually healthy subpopulations, with a high degree of persuasiveness, allows us to assume a close causal link between them. Clarifying the reasons for the identified patterns and their significance requires more detailed studies.

Effects of Low Salinity on the Physiological Indices, Stress-Related Gene Expression, and Histological Changes in Phasolosma Esculenta

Acute saline stress can cause death of Phasolosma esculenta, an important aquaculture species in China. Hence, investigating the sensitivity and physiological responses of P. esculenta to saline stress is important. The molecular, physiological, and immune responses of the intestine and body wall of P. esculenta upon saline stress were investigated in this study. The mortality rate of P. esculenta increased with the decreasing salinity. The Na+/K+-ATPase and acid phosphatase activity peaked at 6 h and 12 h, respectively, in the intestine and body wall, and subsequently stabilized at a higher level than control group. Further, superoxide dismutase activity significantly decreased within 12 h and then increased slowly, while its genes expression decreased and reached its lowest level at 6 h. In the intestine and body wall of P. esculenta, saline stress induced the transcription of Heat Shock Protein-70, Heat Shock Protein-90, and ferritin, along with the enlargement and loosening of connective tissue cells. Moreover, saline stress induced a more prominent adaptive response in the intestine than body wall. This research indicated that the enzymatic system, nonenzymatic system, and gene expressions of P. esculenta changed under low saline stress and provided references for the further research on the low saline stress response in P. esculenta.

Modular Assembly of a Concatenated DNA Circuit for In Vivo Amplified Aptasensing.

Probing endogenous molecular profiles in living entities is of fundamental significance to decipher biological functions and exploit novel theranostics. Despite programmable nucleic acid-based aptasensing systems across the breadth of molecular imaging, an aptasensing system enabling in vivo imaging with high sensitivity, accuracy, and adaptability is highly required yet is still in its infancy. Artificial catalytic DNA circuits that can modularly integrate to generate multiple outputs from a single input in an isothermal autonomous manner, have supplemented powerful toolkits for intracellular biosensing research. Herein, a multilayer nonenzymatic catalytic DNA circuits-based aptasensing system is devised for in situ imaging of a bioactive molecule in living mice by assembling branched DNA copolymers with high-molecular-weight and high-signal-gain based on avalanche-mimicking hybridization chain reactions (HCRs). The HCRs aptasensing circuit performs as a general and powerful sensing platform for precise analysis of a series of bioactive molecules due to its inherent rich recognition repertoire and hierarchical reaction accelerations. With tumor-targeting capsule encapsulation, the HCRs aptasensing circuit is specifically delivered into tumor cells and allowed the high-contrast imaging of intracellular adenosine triphosphate in living mice, highlighting its potential for visualizing these clinically important biomolecules and for studying the associated physiological processes.

Preparation of Non-Enzymatic Glucose Sensing Nanocomposite Based on NiCo<sub>2</sub>O<sub>4</sub> Nanosheets@ Reduced Graphene Oxide and Design of Glucose Detection System

A non-enzymatic glucose sensing nanomaterial which consists of the NiCo2O4 nanosheets grown on reduced graphene oxide (NiCo2O4@rGO) is synthesized by a simple co-precipitation procedure. Firstly, the morphology and composition of the NiCo2O4@rGO are analyzed. Subsequently, the glucose sensing characteristics of the NiCo2O4@rGO are researched by Cyclic Voltammetry and Amperometry. The test results show that the prepared NiCo2O4@rGO has excellent glucose sensing properties. In the two linear detection range of 0.01mM-5.50mM and 5.50mM-15.50mM, the sensitivity reaches 4372.9μA·mM-1cm-2 and 1686.1μA·mM-1cm-2, respectively. In addition, in order to reduce the cost of electrochemical testing and improve the convenience and practicability of detection, a portable potentiostatic glucose detection system based on three electrodes is designed. Through testing, it is found that the non-enzymatic glucose detection system based on NiCo2O4@rGO has good practical application potential in the field of glucose detection.

The Influence of Chlorpyrifos on the Nonenzymatic Antioxidants Content in Macrophytes Leaves.

Water pollution can be moved or limited by macrophytes in a phytoremediation process. The presence of insecticides in the plant life environment may affect physiological processes and contribute to the formation of secondary oxidative stress in plant tissues. To protect against oxidative stress, macrophytes have developed a system of mechanisms consisting of nonenzymatic and enzymatic antioxidants. The influence of various concentrations of chlorpyrifos on the nonenzymatic system in Canadian waterweed (Elodea canadensis Michx.), needle spikerush (Eleocharis acicularis) and water mint (Mentha aquatica L.) was studied. The differences in the value of the total concentration of polyphenols and flavonoids, as well as analysis of chlorophyll-a, chlorophyll-b, anthocyanin and carotenoid concentrations were determined in leaves. Research indicated a significant increase in the content of polyphenols and flavonoids in a solution with the highest concentration of chlorpyrifos while the opposite tendency was observed after analyses of the main assimilating pigments of plant tissues. It was concluded that aqueous plants exposed to toxic insecticide molecules created a defensive mechanism by nonenzymatic antioxidant systems and the amount of low-molecular weight compounds depended on the pollutant concentration which influenced biosynthesis mechanisms in plant cells.

Essential Protective Role of Catalytically Active Antibodies (Abzymes) with Redox Antioxidant Functions in Animals and Humans.

During the life of aerobic organisms, the oxygen resulting from numerous reactions is converted into reactive oxygen species (ROS). Many ROS are dangerous due to their high reactivity; they are strong oxidants, and react with various cell components, leading to their damage. To protect against ROS overproduction, enzymatic and non-enzymatic systems are evolved in aerobic cells. Several known non-enzymatic antioxidants have a relatively low specific antioxidant activity. Superoxide dismutases, catalase, glutathione peroxidase, glutathione S-transferase, thioredoxin, and the peroxiredoxin families are the most important enzyme antioxidants. Artificial antibodies catalyzing redox reactions using different approaches have been created. During the past several decades, it has been shown that the blood and various biological fluids of humans and animals contain natural antibodies that catalyze different redox reactions, such as classical enzymes. This review, for the first time, summarizes data on existing non-enzymatic antioxidants, canonical enzymes, and artificial or natural antibodies (abzymes) with redox functions. Comparing abzymes with superoxide dismutase, catalase, peroxide-dependent peroxidase, and H2O2-independent oxidoreductase activities with the same activities as classical enzymes was carried out. The features of abzymes with the redox activities are described, including their exceptional diversity in the optimal pH values, dependency and independence on various metal ions, and the reaction rate constants for healthy donors and patients with different autoimmune diseases. The entire body of evidence indicates that abzymes with redox antioxidant activities existing in the blood for a long time compared to enzymes are an essential part of the protection system of humans and animals from oxidative stress.

Pulmonary Protein Oxidation and Oxidative Stress Modulation by Lemna minor L. in Progressive Bleomycin-Induced Idiopathic Pulmonary Fibrosis.

Bleomycin (BLM) administration is associated with multifunctional proteins inflammations and induction of idiopathic pulmonary fibrosis (IPF). Lemna minor L. extract, a free-floating monocot macrophyte possesses antioxidant and anti-inflammatory potential. The aim of the study was to examine the protective effect of L. minor extract on lung protein oxidation and oxidative stress modulation by BLM-induced pulmonary fibrosis in Balb/c mice. For this purpose, the protein carbonyl content, advanced glycation end product, nitroxide protein oxidation (5-MSL), and lipid peroxidation (as MDA and ROS), in lung cells were examined. The histological examinations, collagen deposition, and quantitative measurements of IL-1β, IL-6, and TNF in lung tissues and blood were investigated. Intraperitoneal, BLM administration (0.069 U/mL; 0.29 U/kg b.w.) for 33 days, caused IPF induction in Balb/c mice. Pulmonary combining therapy was administered with L. minor at dose 120 mg/mL (0.187 mg/kg b.w.). L. minor histologically ameliorated BLM induced IPF in lung tissues. L. minor significantly modulated (p < 0.05) BLM-alterations induced in lung hydroxyproline, carbonylated proteins, 5-MSL-protein oxidation. Oxidative stress decreased levels in antioxidant enzymatic and non-enzymatic systems in the lung were significantly regulated (p < 0.05) by L. minor. L. minor decreased the IL-1β, IL-6, and TNF-α expression in lung tissues and plasma. The L. minor improves the preventive effect/defense response in specific pulmonary protein oxidation, lipid peroxidation, ROS identifications, and cytokine modulation by BLM-induced chronic inflammations, and could be a good antioxidant, anti-inflammatory, and anti-fibrotic alternative or IPF prevention involved in their pathogenesis.

Pichia caribbica improves disease resistance of cherry tomatoes by regulating ROS metabolism

Black spot caused by Alternaria alternata is one of major diseases of postharvest cherry tomatoes. This study intends to investigate biocontrol efficacy of Pichia caribbica against black spot and explore the mechanisms involved in improved disease resistance of cherry tomatoes through analyzing reactive oxygen species (ROS) metabolism. The results demonstrated that P. caribbica significantly decreased the occurrence of black spot in cherry tomatoes. P. caribbica improved the activities of enzymatic system for ROS scavenging in cherry tomatoes, including some antioxidant enzymes, the enzymes in ascorbic acid-glutathione (AsA-GSH) and glutathione peroxidase (GPX) cycles, and glutathione S-transferase (GST). Furthermore, P. caribbica maintained the high level of the key antioxidant substances and then decreased the production rate of O2¯·, the contents of H2O2 and malondialdehyde (MDA). These results revealed that P. caribbica induced the enzymatic and non-enzymatic systems to remove ROS, and then improved the disease resistance of cherry tomatoes against pathogen. This study will provide new strategy for controlling postharvest disease of fruits and vegetables by improving the ability of ROS scavenging to defense against pathogens.

A new cyanobacterial species with a protective effect on lettuce grown under salinity stress: Envisaging sustainable agriculture practices

In this work, a new terrestrial cyanobacterial species, Oculatella lusitanica LEGE 161147, was isolated and characterized using a polyphasic approach. Morphologically, O. lusitanica shares characteristics with different Oculatella species (mainly with O. crustae-formantes), lacking distinctive features. However, the phylogeny based on the 16S rRNA gene sequence and the 16S-23S ITS secondary structures support the establishment of this isolate as a new species. O. lusitanica is placed within a clade mainly composed by other Oculatella terrestrial strains; however, it forms a separate lineage. In addition, our species differs from the other Oculatella described so far by lacking the V2 helix within the ITS region. Since cyanobacteria are known to release compounds that promote plant growth and/or increase their tolerance to stresses, the effect of this newly described cyanobacterial species on Lactuca sativa (lettuce) plants development and salinity stress resistance was evaluated. Our results showed that, although the cyanobacterium had no impact on plant growth under the conditions tested, it was able to mitigate the deleterious salinity stress effects on plant size, root and aerial part fresh weight, by eliciting the non-enzymatic antioxidant response system (proline, H2O2 and reduced glutathione). In addition, the microorganism was able to induce a priming effect on lettuce plants by stimulating defensive mechanisms under non-stress conditions, and enhances the activity of nitrogen metabolism-related enzymes glutamate dehydrogenase, glutamine synthetase and nitrate reductase. These results indicate that this native terrestrial cyanobacterial species could be employed as a tool in sustainable agricultural practices.

Non-enzymatic modification of the crystalline structure and chemistry of Masson pine in brown-rot decay

Masson pine undergoes rapid degradation by brown-rot fungi, but how the fungus alters the microstructure of Masson pine cell wall is still unclear. In this study, Masson pine samples were incubated with Gloeophyllum trabeum to aid in characterizing changes in the crystalline structure of cellulose and chemical composition of wood in brown-rot decay. Fungal action resulted in an initial increase in wood cellulose crystallinity and crystallite width because of early removal of the more amorphous celluloses, followed by a decrease in crystallinity and crystallite size. All data suggest that hemicellulose, amorphous cellulose and crystalline cellulose are sequentially depolymerized via a non-enzymatic pathway, concurrent with early-stage changes in the rearrangement of cellulose chains and the diffusion of depolymerized less-crystalline polysaccharides out of the cell wall. Our work provides insight into the role of a non-enzymatic system in brown-rot decay as well as its potential application in lignocellulose preservation and biorefineries.

Synergistic Association With Root Endophytic Fungi Improves Morpho-Physiological and Biochemical Responses of Chenopodium quinoa to Salt Stress

Symbiotic associations with microbes can contribute to mitigating abiotic environmental stress in plants. In this study, we investigated individual and interactive effects of two root endophytic fungal species on physiological and biochemical mechanisms of the crop Chenopodium quinoa in response to salinity. Fungal endophytes (FE) Talaromyces minioluteus and Penicillium murcianum, isolated from quinoa plants that occur naturally in the Atacama Desert, were used for endophyte inoculation. A greenhouse experiment was developed using four plant groups: (1) plants inoculated with T. minioluteus (E1+), (2) plants inoculated with P. murcianum (E2+), (3) plants inoculated with both fungal species (E1E2+), and (4) non-inoculated plants (E-). Plants from each group were then assigned to either salt (300 mM) or control (no salt) treatments. Differences in morphological traits, photosynthesis, stomatal conductance, transpiration, superoxide dismutase (SOD), ascorbate peroxidase (APX), peroxidase, (POD), phenylalanine ammonia-lyase (PAL), phenolic content, and lipid peroxidation between plant groups under each treatment were examined. We found that both endophyte species significantly improved morphological and physiological traits, including plant height, number of shoots, photosynthesis, stomatal conductance, and transpiration, in C. quinoa in response to salt, but optimal physiological responses were observed in E1E2+ plants. Under saline conditions, endophyte inoculation improved SOD, APX, and POD activity by over 50%, and phenolic content by approximately 30%, with optimal enzymatic responses again observed in E1E2+ plants. Lipid peroxidation was significantly lower in inoculated plants than in non-inoculated plants. Results demonstrate that both endophyte species enhanced the ability of C. quinoa to cope with salt stress by improving antioxidative enzyme and non-enzyme systems. In general, both FE species interacting in tandem yielded better morphological, physiological, and biochemical responses to salinity in quinoa than inoculation by a single species in isolation. Our study highlights the importance of stress-adapted FE as a biological agent for mitigating abiotic stress in crop plants.

中华蚊母树在干旱-水淹交叉胁迫下形态和活性氧代谢的适应机制

PDF HTML阅读 XML下载 导出引用 引用提醒 中华蚊母树在干旱-水淹交叉胁迫下形态和活性氧代谢的适应机制 DOI: 10.5846/stxb202008062050 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（51779127）；国家111引智基地项目（D20015）；中国科学院水生植物与流域生态重点实验室开放课题基金（E0520204）；三峡库区珍稀植物种子保存技术与设施研究科研项目-耐水淹种质资源调查及收集（SDHZ2021346） Adaptive mechanism of morphology and reactive oxygen species metabolism of Distylium chinense seedlings to alternate drought and submergence stresses Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为阐明中华蚊母树（Distylium chinense）在消落带干旱-水淹交叉胁迫下的形态和活性氧（ROS）代谢适应机制，通过控制实验模拟了三峡水库消落带的水文节律，研究了干旱-水淹交叉胁迫及恢复过程施加不同外源物质对中华蚊母树形态学和ROS清除的变化。结果表明：（1）前期干旱胁迫增强了中华蚊母树对后期水淹胁迫的适应，主要表现在叶片脱落、大量不定根的形成及茎基部膨大等形态学的变化；（2）干旱或水淹单一胁迫下，中华蚊母树·OH、O2·等ROS水平明显高于对照，表现出氧化应激反应，其超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、抗坏血酸过氧化物酶（APX）等抗氧化系统酶活性及脯氨酸（Pro）等抗氧化系统小分子含量也均显著高于对照，表现出一定的抗氧化防御作用机制，且在复合胁迫下，SOD、CAT、APX酶活性及Pro含量显著高于单一胁迫；（3）恢复阶段，相关性分析表明，中华蚊母树清除ROS （·OH、O2·）的酶促（SOD、CAT、APX）及非酶促（Pro）系统具有一定的协同性。同时，恢复阶段施加脱落酸（ABA），内源Pro显著高于正常水平；施加Pro，SOD、CAT等抗氧化酶活性显著高于对照；施加可溶性糖（Glu），APX活性显著升高。表明外源添加ABA、Pro、Glu，均对ROS的清除产生显著影响，同时，SOD活性显著高于CAT和APX活性，因此SOD可能是中华蚊母树清除冗余ROS的主要因子。因此，中华蚊母树形态学的变化、较高的脯氨酸积累和对ROS有效的清除防御，可能是其适应干旱-水淹交叉胁迫的主要机制，ABA、Pro、Glu等外源物质的添加对中华蚊母树的胁迫恢复过程具有显著的促进作用，前期干旱可提高中华蚊母树植株对后期水淹的耐受能力。 Abstract:Distylium chinense, the genus Distylium of the Hamamelidacea, is an evergreen perennial shrub between 0.8 and 1.2 m in height, native to the riparian areas and wetlands and a dominant species in the riparian areas of the Three Gorges Reservoir (TGR) region of the Yangtze River and its branches. Our previous studies showed that D. chinense had a certain survival rate in the middle and upper part of the water level fluctuation zone (WLFZ) of the TGR to alternate drought and submergence stresses, but the adaptive mechanisms of its morphology and reactive oxygen species (ROS) metabolism is still unknown. To evaluate its adaptation mechanisms of D. chinense to alternate drought and submergence stresses, a simulation alternate drought and submergence experiment was conducted, and morphology and ROS metabolism of D. chinense seedlings and their recovery growth with different exogenous substances, i.e., abscisic acid(ABA), proline(Pro) and glucose (Glu), were analyzed, including adventitious roots, plant height, base stem diameter, leaf numbers, ROS content, enzymatic and non-enzymatic antioxidant parameters. The results were as follows. (1) The early drought stress stimulated the adaptation of D. chinense seedlings to the later flooding stress.The adaptation mainly refered as more morphological changes of stems and roots i.e., stem base hypertrophy, formation and development of adventitious roots. (2) Comparing to the control group, there were significant increases in the ·OH and the O2· in D. chinense seedlings under either drought or flooding stress, which showed oxidative stress responses occurred and their superoxide dismutase (SOD), ascorbate peroxidase (APX), and catalase (CAT) activities and the proline (Pro) contents were also significantly higher than those of controls, which showed that the enzymatic and non-enzymatic antioxidants were induced as a defense mechanism. Under the alternate drought and submergence stresses, the activities of SOD, APX and CAT and Pro contents were higher than those under single drought or flooding stress. (3) Correlation analysis showed that to a certain extent there were coordinated effects between the enzymatic (SOD, CAT, APX) and non-enzymatic (Pro) systems in ROS-scavenging in D. chinense. Exogenous ABA significantly triggered an increase of endogenous Pro contents compared to the controls during the recovery growth and the activity of SOD, CAT and APX was significantly higher than those of the control group under exogenous Pro treatment. Of these, the activities of SOD were significantly higher than those of CAT and APX. The activities of APX increased significantly when soluble sugar (Glu) was added. The ABA, Pro and Glu all had significant influences on the removal of ROS and the ability of D. chinense to up-regulate the SOD activity might be an important attribute for the removal of redundant ROS linked to drought and flooding tolerance. Thus the higher Pro accumulation and effective defense to ROS could be the main physiological adaptation mechanisms for D. chinense under the alternate drought and submergence stresses. The combination of morphological changes and the up-regulating of enzymatic and non-enzymatic anti-oxidative system might be the main mechanisms of D. chinense adapting to alternate drought and flooding stresses. The ABA, Pro and Glu treatment significantly promoted the recovery growth of D. chinense.. The drought in the early stage could improve the tolerance to submergence in the later stage. 参考文献 相似文献 引证文献

Wireless Non-Enzymatic Glucose Sensing System with Pt-Ni Nanocomposite and Silica Nanoporous Membrane Modified Electrodes for Different Disease Monitoring

Wireless Non-Enzymatic Glucose Sensing System with Pt-Ni Nanocomposite and Silica Nanoporous Membrane Modified Electrodes for Different Disease Monitoring

Biliary cirrhosis-induced cardiac abnormality in rats: Interaction between Farnesoid-X-activated receptors and the cardiac uncoupling proteins 2 and 3.

This study aimed to evaluate the relationship between Farnesoid-X-activated receptors (FXR) as nuclear regulators of the antioxidant defense system as well as cardiac mitochondrial carrier proteins of UCP2 and UCP3 in cardiac damage induced by cirrhosis. Twenty-two male Wistar rats (200-250 g) were randomly divided into 3 experimental groups, including a control group (n=6), a sham-operated group (n=8), and a bile duct ligated (BDL) group (n=8). Four weeks after surgical intervention, biochemical assessment (AST, ALT, GGT, LDH, and ALP), histological observation, and molecular evaluation (FXR, UCP2, UCP3, BNP, Caspase3, and GAPDH) using real-time RT-PCR were performed. Compared with the sham-operation group, the BDL group showed a significant rise in liver enzymes of AST, ALT, GGT, LDH, and ALP. Defined fibrotic and necrotic bundles and thick reticulin fibers were also found in BDL liver tissue. Besides liver morphological alterations, left ventricles of BDL ones were also associated with defined cardiomyocyte hypertrophy, myofiber vacuolization, and clear pigmentation. Findings showed a significant up-regulation of cardiac Brain Natriuretic Peptide (BNP) along with marked down-regulation in hepatic FXR, cardiac FXR, and cardiac UCP2 and UCP3. However, the expression of caspase 3 in the cardiac tissue was not affected by BDL operation during 4 weeks. Expression of FXR as an upstream regulator of cellular redox status, besides the non-enzymatic ROS buffering defense system of cardiac UCPs, has a pivotal role in the pathogenesis of cirrhotic-induced cardiac abnormality in rats.

ROS-scavenging-associated transcriptional and biochemical shifts during nectarine fruit development and ripening

ROS are known as toxic by-products but also as important signaling molecules playing a key role in fruit development and ripening. To counteract the negative effects of ROS, plants and fruit own multiple ROS-scavenging mechanisms aiming to ensure a balanced ROS homeostasis. In the present study, changes in specific ROS (i.e. H2O2) as well as enzymatic (SOD, CAT, POX, APX) and non-enzymatic (phenylpropanoids, carotenoids and ascorbate) ROS-scavenging systems were investigated along four different stages of nectarine (cv. ‘Diamond Ray’) fruit development and ripening (39, 70, 94 and 121 DAFB) both at the metabolic (28 individual metabolites or enzymes) and transcriptional level (24 genes). Overall, our results demonstrate a complex ROS-related transcriptome and metabolome reprogramming during fruit development and ripening. At earlier fruit developmental stages an increase on the respiration rate is likely triggering an oxidative burst and resulting in the activation of specific ethylene response factors (ERF1). In turn, ROS-responsive genes or the biosynthesis of specific antioxidant compounds (i.e. phenylpropanoids) were highly expressed or accumulated at earlier fruit developmental stages (39–70 DAFB). Nonetheless, as the fruit develops, the decrease in the fruit respiration rate and the reduction of ERF1 genes leads to lower levels of most non-enzymatic antioxidants and higher accumulation of H2O2. Based on available literature and the observed accumulation dynamics of H2O2, it is anticipated that this compound may not only be a by-product of ROS-scavenging but also a signaling molecule accumulated during the ripening of nectarine fruit.

6-Benzylaminopurine Alleviates the Impact of Cu2+ Toxicity on Photosynthetic Performance of Ricinus communis L. Seedlings.

Copper (Cu) is an essential element involved in various metabolic processes in plants, but at concentrations above the threshold level, it becomes a potential stress factor. The effects of two different cytokinins, kinetin (KIN) and 6-benzylaminopurine (BAP), on chlorophyll a fluorescence parameters, stomatal responses and antioxidation mechanisms in castor (Ricinus communis L.) under Cu2+ toxicity was investigated. Ricinus communis plants were exposed to 80 and 160 μM CuSO4 added to the growth medium. Foliar spraying of 15 μM KIN and BAP was carried out on these seedlings. The application of these cytokinins enhanced the tissue water status, chlorophyll contents, stomatal opening and photosynthetic efficiency in the castor plants subjected to Cu2+ stress. The fluorescence parameters, such as Fm, Fv/Fo, Sm, photochemical and non-photochemical quantum yields, energy absorbed, energy trapped and electron transport per cross-sections, were more efficiently modulated by BAP application than KIN under Cu2+ toxicity. There was also effective alleviation of reactive oxygen species by enzymatic and non-enzymatic antioxidation systems, reducing the membrane lipid peroxidation, which brought about a relative enhancement in the membrane stability index. Of the various treatments, 80 µM CuSO4 + BAP recorded the highest increase in photosynthetic efficiency compared to other cytokinin treatments. Therefore, it can be concluded that BAP could effectively alleviate the detrimental effects of Cu2+toxicity in cotyledonary leaves of R. communis by effectively modulating stomatal responses and antioxidation mechanisms, thereby enhancing the photosynthetic apparatus’ functioning.

Preparation of acylated chitosan with caffeic acid in non-enzymatic and enzymatic systems: Characterization and application in pork preservation

To further improve the performance of chitosan in food processing and preservation, this study investigated the grafting of the caffeic acid onto the chitosan in non-enzymatic and enzymatic systems. Result suggested that the caffeic acid was successfully incorporated into the chitosan in the non-enzymatic system, and the grafting ratio of modified chitosan (CA@CTS-N) was 7.49%. Moreover, lipase had a significant positive effect on the grafting reaction of the chitosan, and the modified chitosan prepared in enzymatic system (CA@CTS-E) obtained a higher grafting ratio, which was 11.82%. In both systems, the carboxyl of the caffeic acid was bonded to the amino of the chitosan and formed carbonyl ammonia. After the introduction of foreign group, many changes occurred in the functional properties of the modified chitosan. First, the water solubility of the chitosan was significantly improved from 0.00285 (native chitosan, CTS) to 0.221 (CA@CTS-N) and 0.774 g/100 mL (CA@CTS-E). The caffeoyl had a significant impact on the emulsifying properties of the chitosan. Compared with those of CTS, the modified chitosan had stronger antioxidation and antibacterial activities against Escherichia coli, Staphylococcus aureus, and Candida albicans. Finally, the pork treated with the modified chitosan exhibited longer shelf life than that treated with CTS.

Biochemical and Physiological Responses of Harmful Karenia mikimotoi to Algicidal Bacterium Paracoccus homiensis O-4.

Harmful algal blooms caused by Karenia mikimotoi frequently occur worldwide and severely threaten the marine environment. In this study, the biochemical and physiological responses of K. mikimotoi to the algicidal bacterium Paracoccus homiensis O-4 were investigated, and the effects on the levels of reactive oxygen species (ROS), malondialdehyde content, multiple antioxidant systems and metabolites, photosynthetic pigments, and photosynthetic index were examined. The cell-free supernatant in strain O-4 significantly inhibited K. mikimotoi cell growth. The bacterium caused the K. mikimotoi cells to activate their antioxidant defenses to mitigate ROS, and this effect was accompanied by the upregulation of intracellular antioxidant enzymes and non-enzyme systems. However, the overproduction of ROS induced lipid peroxidation and oxidative damage within K. mikimotoi cells, ultimately leading to algal death. In addition, the photosynthetic efficiency of the algal cells was significantly inhibited by O-4 and was accompanied by a reduction in photosynthetic pigments. This study indicates that O-4 inhibits K. mikimotoi through excessive oxidative stress and impaired photosynthesis. This research into the biochemical and physiological responses of K. mikimotoi to algicidal bacteria provides insights into the prophylaxis and control of harmful algal blooms via interactions between harmful algae and algicidal bacteria.