The effect of foliar application of Ascophyllum nodosum (L.) Le Jol. seaweed extract on biochemical traits related to abiotic stresses in pistachio (Pistacia vera L. cv. Kaleh-Ghoochi).

BACKGROUND: Due to the important economic role of pistachio (Pistacia vera L.) the cultivation of this valuable crop has been extended. Various abiotic stresses harm the growth and performance of pistachio. Seaweed extract containing various substances such as pseudo-hormones that stimulate growth, nutritional elements, and anti-stress substances can cause more resistance to abiotic stresses, and increase the quantity and the quality of the fruit. The present study was conducted to evaluate the effect of foliar application of Ascophyllum nodosum (L.) Le Jol. seaweed extract on some biochemical traits related to abiotic stress in Pistacia vera L. cv. Kaleh-Ghoochi. The first factor of foliar spraying treatment included A. nodosum seaweed extract at four levels (0, 1, 2, and 3 g/L), and the second factor was the time of spraying solution which was done at three times (1- at the beginning of pistachio kernel growth period at the end of June, 2- at the stage of full kernel development at the end of August, and 3- Spraying in both late June and August). RESULTS: The results showed that all investigated traits were significant under the treatment of seaweed extract compared with the control. The seaweed extract concentrations had a significant effect on all traits except soluble carbohydrates, but the time of consumption of seaweed extract on soluble carbohydrates, protein, peroxidase, ascorbate peroxidase, and superoxide dismutase enzymes was significant, while had no significant effect on the rest of the traits. According to the interaction effect of time and concentration of consumption of seaweed extract, the highest values of the biochemical characters were as follows: total phenol content: 168.30 mg CAE/g DW, flavonoid content: mg CE/g DW, catalase: 12.66 µmol APX min- 1 mg- 1 protein, superoxide dismutase: 231.4 µmol APX min- 1 mg- 1 protein, and ascorbate peroxidase: 39.53 µmol APX min- 1 mg- 1 protein. CONCLUSIONS: Based on the results of this study, it seems that it is possible to use fertilizers containing A. nodosum seaweed extract with a concentration of 3 g/L in August to increase the tolerance of the pistachio cultivar "Kaleh-Ghoochi" to abiotic stresses.

Toxicity of methylparaben and its chlorinated derivatives to Allium cepa L. and Eisenia fetida Sav.

Methylparaben, chloro-methylparaben, and dichloro-methylparaben were evaluated in Allium cepa at 5, 10, 50, and 100 µg/L and in Eisenia fetida at 10 and 100 µg/L. In A. cepa roots, 100 µg/L methylparaben and 50 and 100 µg/L chlorinated methylparabens reduced cell proliferation, caused cellular changes, and reduced cell viability in meristems, which caused a reduction in root growth. Furthermore, they caused drastic inhibition of catalase, ascorbate peroxidase, and superoxide dismutase; activated guaiacol peroxidase and promoted lipid peroxidation in meristematic root cells. In earthworms, after 14 days exposure to the three compounds, there were no deaths, and catalase, ascorbate peroxidase, and superoxide dismutase were not inhibited. However, guaiacol peroxidase activity and lipid peroxidation were observed in animals exposed to dichloro-methylparaben. Soils with dichloro-methylparaben also caused the escape of earthworms. It is inferred that the recurrent contamination of soils with these methylparabens, with emphasis on chlorinated derivatives, can negatively impact different species that depend directly or indirectly on soil to survive.

Co-exposure of sulfur nanoparticles and Cu alleviate Cu stress and toxicity to oilseed rape Brassica napus L.

Experiments were performed to explore the impact of sulfur nanoparticles (SNPs) on growth, Cu accumulation, and physiological and biochemical responses of oilseed rape (Brassica napus L.) inoculated with 5 mg/L Cu-amended MS medium supplemented with or without 300 mg/L SNPs exposure. Cu exerted severe phytotoxicity and inhibited plant growth. SNPs application enhanced the shoot height, root length, and dry weight of shoot and root by 34.6%, 282%, 41.7% and 37.1%, respectively, over Cu treatment alone, while the shoot and root Cu contents and Cu-induced lipid perodixation as the malondialdehyde (MDA) levels in shoots and roots were decreased by 37.6%, 35%, 28.4% and 26.8%. Further, the increases in superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX), glutathione reductase (GR) and glutathione S-transferase (GST) enzyme activities caused by Cu stress were mitigated in shoots (10.9%-37.1%) and roots (14.6%-35.3%) with SNPs addition. SNPs also positively counteracted the negative effects on shoot K, Ca, P, Mg, Mn, Zn and Fe contents and root K, Ca, Mg and Mn contents from Cu exposure alone, and significantly promoted the nutrients accumulation in plant. Additionally, in comparison with common bulk sulfur particles (BSPs) and sulfate, SNPs showed more positive effects on promoting growth in shoots (6.7% and 19.5%) and roots (10.9% and 15.1%), as well as lowering the shoot Cu content (40.1% and 43.3%) under Cu stress. Thus, SNPs application has potential to be a green and sustainable technology for increasing plant productivity and reducing accumulation of toxic metals in heavy metal polluted soils.

Combined Inhibitory Effect of Canada Goldenrod Invasion and Soil Microplastics on Rice Growth.

Alien plant invasion and residual soil microplastics (MPs) are growing threats to agricultural crop production. This study determined the adverse effects of Canadian goldenrod (Solidago canadensis L.) invasion and residual soil MPs on rice growth and development. The biomass, phenological indices, photosynthetic parameters, and antioxidant enzyme activities of rice were measured on the 50th and 80th day of post-plantation. Biomass and phenotypic results indicated the more harmful effects of the combination of S. canadensis invasion and residual soil MPs compared to S. canadensis invasion or residual soil MPs effects alone. Moreover, the interaction effect of S. canadensis invasion and residual soil MPs markedly reduced the ascorbate peroxidase and catalase belowground, while they increased in the aboveground parts of the rice. However, the S. canadensis invasion and residual soil MPs interactive treatments lowered the superoxide dismutase concentrations in the belowground parts of the rice plants while elevating the peroxidase and reactive oxygen species concentrations in both the belowground and aboveground parts compared to the other treatments. Among all treatments, S. canadensis invasion alone had the most negligible negative impact on rice biomass and growth indices. Our study suggests that soil MPs could negatively affect crop production with invasive alien plants, and the combined effects were more harmful than either of the single factors. Our findings will lay the groundwork for analyzing the impacts of invasive alien plants on rice crops.

Effects of exogenous taurine on growth, photosynthesis, oxidative stress, antioxidant enzymes and nutrient accumulation by Trifolium alexandrinum plants under manganese stress.

Plants essentially require manganese (Mn) for their normal metabolic functioning. However, excess Mn in the cellular environment is detrimental to plant growth, development, and physio-biochemical functions. Taurine (TAU) is an amino acid with potent antioxidant and anti-inflammatory properties in animals and humans. However, no previous study has investigated the potential of TAU in plant metal stress tolerance. The current study provides some novel insights into the effect of TAU in modulating the defense system of Trifolium alexandrinum plants under Mn toxicity. Manganese toxicity resulted in higher oxidative stress and membrane damage through increased superoxide radical, hydrogen peroxide, malondialdehyde, and methylglyoxal generation alongside enhanced lipoxygenase (LOX) activity. Mn toxicity also resulted in limited uptake of potassium (K+), phosphorus (P), calcium (Ca2+), and increased the accumulation of Mn in both leaf and roots. However, TAU circumvented the Mn-induced oxidative stress by upregulating the activities of antioxidant enzymes (ascorbate peroxidase, peroxidase, catalase, glutathione reductase, glutathione-S-transferase, and superoxide dismutase) and levels of ascorbic acid, proline, anthocyanins, phenolics, flavonoids and glutathione (GSH). Taurine conspicuously improved the growth, photosynthetic pigments, hydrogen sulphide (H2S), and nitric oxide (NO) levels of Mn stressed plants. Taurine also improved the uptake of K+, Ca2+, P and reduced the Mn content in stressed plants. Overall, exogenous taurine might be a suitable strategy to combat Mn stress in T. alexandrinum plants but applications at field levels for various crops and metal toxicities and economic suitability need to be addressed before final recommendations.

Impact of repeated freeze-thaw cycles environment on the allelopathic effect to Secale cereale L. seedlings.

Allelopathy, as environmental stress, plays a prominent role in stress ecotoxicity, and global warming directly increases freeze-thaw cycles (FTCs) frequency in the winter. Yet, the effect between FTCs environment and allelopathy stress is rarely known, and the interaction of allelopathy stresses lacks consideration. Here, we addressed interactions between artemisinin stress (AS) and A. trifida extract stress (AES) under Non-FTCs and FTCs environments. The results found that AS and AES had an antagonistic relation under Non-FTCs environment, while a strong synergism and cooperation under FTCs environment affect the growth and physiology in S. cereale seedlings. Besides, AS and AES under FTCs environment had more inhibition on the growth of roots and shoots, chlorophylls, photosynthetic parameters, and relative water content; while more promotion on malondialdehyde, soluble sugar, and soluble protein. Moreover, the antioxidant enzyme activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and ascorbate peroxidase (APX) were increased by AS and AES, showing a good resistance of S. cereale seedlings to allelopathy stress, but FTCs environment significantly weakened this resistance. Thus, the allelopathic effect of AS and AES on S. cereale seedlings was significantly emphasized by FTCs environment.

Biotic elicitor-induced changes in growth, antioxidative defense, and metabolites in an improved prickleless Solanum viarum.

Solanum viarum serves as a raw material for the steroidal drug industry due to its alkaloid and glycoalkaloid content. Elicitation is well-known for measuring the increase in the yield of bioactive compounds in in vitro cultures. The current study was performed for the accumulation of metabolites viz. solasodine, solanidine, and α-solanine in S. viarum culture using microbial-based elicitors added in 1%, 3%, 5%, and 7% on 25th and 35th day of culture period and harvested on 45th and 50th days of culture cycle. The treatment of 3% Trichoderma reesei and Bacillus tequilensis culture filtrate (CF) significantly increased biomass, alkaloids/glycoalkaloid content, and yield in S. viarum. T. reesei was found to be the best treatment for enhanced growth (GI = 11.65) and glycoalkaloid yield (2.54 mg DW plant-1) after the 50th day of the culture cycle when added on the 25th day. The abundance of gene transcripts involved in the biosynthesis of alkaloids/glycoalkaloids, revealed by quantitative real-time PCR expression analysis correlates with the accumulation of their respective metabolites in elicited plants. Biochemical analysis shows that elicited plants inhibited oxidative damage caused by reactive oxygen species by activating enzymes (superoxide dismutase and ascorbate peroxidase) as well as non-enzymatic antioxidant mechanisms (alkaloids, total phenols, total flavonoids, carotenoids, and proline). The findings of this study clearly demonstrate that the application of T. reesei and B. tequilensis CF at a specific dose and time significantly improve biomass as well as upregulates the metabolite biosynthetic pathway in an important medicinal plant- S. viarum. KEY POINTS: • Biotic elicitors stimulated the alkaloids/glycoalkaloid content in S. viarum plant cultures. • T. reesei was found to be most efficient for enhancing the growth and alkaloids content. • Elicited plants activate ROS based-defense mechanism to overcome oxidative damage.

A Validated Set of Ascorbate Peroxidase-Based Organelle Markers for Electron Microscopy of Saccharomyces cerevisiae.

Genetically encoded tags, such as engineered ascorbate peroxidase APEX2, offer unique advantages for the specific labeling of subcellular structures in electron microscopy (EM). However, the use of APEX2 in EM investigation of yeast has been limited. Here we describe the development of APEX2-based organelle markers for Saccharomyces cerevisiae. We found that with regard to APEX2 -catalyzed formation of diaminobenzidine precipitation, cell wall removal was not essential during sample preparation, yet the presence of fluorescent proteins in APEX2 chimeras had a negative impact. We showed that major organelles including endoplasmic reticulum, early Golgi, late Golgi/early endosomes, late endosomes, mitochondria, peroxisomes, and lipid droplets could be labeled by appropriate APEX2 chimeras. The subcellular localization of our APEX2 chimeras was verified by EM visualization and supplemented with immunofluorescence colocalization analysis when necessary, validating their feasibility as organelle markers. IMPORTANCE Yeast is an excellent single cellular model system for studying basic cellular processes. However, yeast cells are much smaller than most animal and plant cells, making the observation and recognition of yeast subcellular structures challenging. Here we developed a set of yeast organelle markers for use in electron microscopy and documented our technical approach for using this method.

CfAPX, a cytosolic ascorbate peroxidase gene from Cryptomeria fortunei, confers tolerance to abiotic stress in transgenic Arabidopsis.

Plants subjected to biotic or abiotic stresses produce a large amount of reactive oxygen species (ROS). If ROS cannot be cleared in time, they cause a series of harmful reactions in plants. Ascorbate peroxidase (APX) is a key enzyme that removes ROS from plant cells and plays a vital role in plant stress resistance. However, to date, no studies on APX homologs in Cryptomeria fortunei have been reported. In this study, we isolated complementary DNA (cDNA) encoding APXfrom C. fortunei needles, which is referred to as CfAPX, by rapid amplification of cDNA ends (RACE). The full-length CfAPX sequence was 1226 bp in length and included a 750-bp open reading frame (ORF) encoding a protein of 249 amino acids. Phylogenetic analysis showed that APXs of different plant species have been highly evolutionarily conserved. CfAPX was shown to belong to the cytoplasmic subgroup and was more closely related to GbAPX of the gymnosperm Ginkgo biloba. CfAPX showed no transcriptional activity in yeast cells but was highly expressed in cones. To better handle abiotic stresses, compared with wild-type (WT) Arabidopsis thaliana, 35S::CfAPX transgenic Arabidopsis strongly expressed CfAPX, presented increased antioxidant enzyme activities, ascorbic acid (AsA) contents, chlorophyll levels and fluorescence parameter and reduced malondialdehyde (MDA) and hydrogen peroxide (H2O2) contents. In addition, CfAPX expression in C. fortunei was mostly upregulated under stress. In summary, CfAPX confers abiotic stress responses to plants, which provides a scientific basis for subsequent breeding for increased stress resistance in C. fortunei.

Antioxidant enzyme responses and metabolite functioning of Pisum sativum L. to sewage sludge in arid and semi-arid environments.

The productivity of plants is a direct variant of the countless biotic and abiotic stresses to which a plant is exposed in an environment. This study aimed to investigate the capabilities of leguminous plant garden pea (Pisum sativum L.) to resist water deficit conditions in arid and semi-arid areas when applied with varied doses of sludge for growth response. The effect of sludge doses was evaluated on crop yield, antioxidant enzymes, viz., ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR), superoxide dismutase (SOD), and glutathione reductase (GR), and metabolites (ascorbic acid, glutathione, and total protein content). The effective sludge concentrations with respect to seed weight and crop yield were found to be in the following trend: D2 (6.25%)>D3 (12.5%)>D1 (2.5%)>D0 (control) under organic amendment (OA). Conversely, a high dose of the sludge reduced the seed weight and total crop yield. The sludge doses D2 under arid and semi-arid conditions along with organic amendments (OA) significantly enhance the antioxidant enzyme activity, whereas sludge dose D3 with OA ominously regulates the activity of these enzymes. Besides, seeds depicted a considerable increase in ascorbic acid, glutathione, and total protein content in arid and semi-arid conditions upon the application of sludge with OA. Sewage sludge as a source of nutrients indirectly enhances crop yield, antioxidant enzymes, and antioxidant metabolites. Thus, it improves the defense mechanism, reduces abnormal protein glycation, and depletes the susceptibility of protein to proteolysis.

Integration of signals from different cortical areas in higher order thalamic neurons.

Higher order thalamic neurons receive driving inputs from cortical layer 5 and project back to the cortex, reflecting a transthalamic route for corticocortical communication. To determine whether or not individual neurons integrate signals from different cortical populations, we combined electron microscopy "connectomics" in mice with genetic labeling to disambiguate layer 5 synapses from somatosensory and motor cortices to the higher order thalamic posterior medial nucleus. A significant convergence of these inputs was found on 19 of 33 reconstructed thalamic cells, and as a population, the layer 5 synapses were larger and located more proximally on dendrites than were unlabeled synapses. Thus, many or most of these thalamic neurons do not simply relay afferent information but instead integrate signals as disparate in this case as those emanating from sensory and motor cortices. These findings add further depth and complexity to the role of the higher order thalamus in overall cortical functioning.

Identification and Characterization of the APX Gene Family and Its Expression Pattern under Phytohormone Treatment and Abiotic Stress in Populus trichocarpa.

Ascorbate peroxidase (APX) is a member of class I of the heme-containing peroxidase family. The enzyme plays important roles in scavenging reactive oxygen species for protection against oxidative damage and maintaining normal plant growth and development, as well as in biotic stress responses. In this study, we identified 11 APX genes in the Populus trichocarpa genome using bioinformatic methods. Phylogenetic analysis revealed that the PtrAPX proteins were classifiable into three clades and the members of each clade shared similar gene structures and motifs. The PtrAPX genes were distributed on six chromosomes and four segmental-duplicated gene pairs were identified. Promoter cis-elements analysis showed that the majority of PtrAPX genes contained a variety of phytohormone- and abiotic stress-related cis-elements. Tissue-specific expression profiles indicated that the PtrAPX genes primarily function in roots and leaves. Real-time quantitative PCR (RT-qPCR) analysis indicated that PtrAPX transcription was induced in response to drought, salinity, high ammonium concentration, and exogenous abscisic acid treatment. These results provide important information on the phylogenetic relationships and functions of the APX gene family in P. trichocarpa.

The effect of NADPH oxidase inhibitor diphenyleneiodonium (DPI) and glutathione (GSH) on Isatis cappadocica, under Arsenic (As) toxicity.

The present work was conducted to assess the effects of arsenic (As, 1000 µM), diphenyleneiodonium (DPI, 10 µM) and reduced glutathione (GSH, 500 µM) on Isatis cappadocica. As treatment decreased plant growth and fresh and dry weight of shoot and root and also enhanced the accumulation of As. As stress also enhanced the oxidative stress biomarkers, hydrogen peroxide (H2O2) and malondialdehyde (MDA) content. However, the application of GSH decreased the content of H2O2 and MDA by 43% and 55%, respectively, as compared to As treatment. The antioxidants like superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX), glutathione reductase (GR) and glutathione S-transferase (GST) also enhanced with As stress. NADPH oxidase inhibitor, the DPI, enhances the effect of As toxicity by increasing the accumulation of As, H2O2, MDA. DPI also enhances the activity of antioxidant enzymes except GR and GST, However, the application GSH increased the plant growth and biomass yield, decreases accumulation of As, H2O2 and MDA content in As as well as As + DPI treated plants. The thiols content [total thiol (TT), non-protein thiol (NPT) protein thiols (PT), and glutathione (GSH)] were decreased in the As + DPI treatment but supplementation of GSH enhanced them. Novelty statement: The study reveals the beneficial role of GSH in mitigating the deleterious effects of Arsenic toxicity through its active involvement in the antioxidant metabolism, thiol synthesis and osmolyte accumulation. Apart from As, We provided the plants NADPH oxidase inhibitor, the diphenyleneiodonium (DPI), which boosts the As toxicity. At present, there is dearth of information pertaining to the effects of DPI on plants growth and their responses under heavy metal stress.GSH application reversed the effect of diphenyleneiodonium (DPI) under As stress preventing the oxidative damage to biomolecules through the modulation of different antioxidant enzymes. The application of GSH for As stressed soil could be a sustainable approach for crop production.

Selenium biofortification enhances ROS scavenge system increasing yield of coffee plants.

There are conclusive evidences of selenium (Se) deficiency in Brazilian soils and foods. Brazil is the largest producer and consumer of coffee worldwide, which favors agronomic biofortification of its coffee. This study aimed to evaluate effects of foliar application of three formulations and six rates of Se on antioxidant metabolism, agronomic biofortification and yield of coffee beans. Seven Se concentrations (0, 10, 20, 40, 80, 100 and 160 mg L-1) were applied from three formulations of Se (sodium selenate, nano-Se 1500, and nano-Se 5000). Selenium application up to 40 mg L-1 increased the concentration of photosynthetic pigments such as chlorophylls, pheophytins and carotenoids in coffee leaves. Foliar application of Se ranging from 20 to 80 mg L-1 decreased lipid peroxidation and concentration of hydrogen peroxide, but increased superoxide dismutase, ascorbate peroxidase, catalase and glutathione reductase activities in coffee leaves. These results indicated that foliar Se application stimulates antioxidative metabolism to mitigate reactive oxygen species. Foliar application of 20 mg Se L-1 of sodium selenate increased coffee yield by 38%, and 160 mg Se L-1 of nano-Se 5000 increased dramatically coffee yield by 42%. Selenium concentration in grains ranged from 0.116 to 4.47 mg kg-1 (sodium selenate), 4.84 mg kg-1 (nano-Se 1500) and 5.82 mg kg-1 (nano-Se 5000). The results suggest the beneficial effect of Se on the increment of photosynthetic pigments, antioxidative metabolism, increased coffee yield and nutritional quality of grains. The recommended foliar Se application in this study can mitigate abiotic stressors such as high temperatures resulting in higher yield of coffee plants.

Hydrogen peroxide modulates activity and expression of antioxidant enzymes and protects photosynthetic activity from arsenic damage in rice (Oryza sativa L.).

We studied the role of H2O2 in the protection of photosynthesis from arsenic (As) damage in rice (Oryza sativa L.) by examining the antioxidant system, photosynthesis, and growth attributes. Among the As concentrations (0, 20, 30, 40 and 50 µM) tested, maximum oxidative stress and inhibition in photosynthesis and growth were found with 50 µM As. The application of 50 µM H2O2 resulted in alleviation of the adverse effects of 50 µM As on Pigment System (PS) II activity, photosynthesis, and growth. Hydrogen peroxide supplementation induced the activity of superoxide dismutase (SOD), ascorbate peroxidase (APX) and glutathione reductase (GR) and increased reduced glutathione (GSH) content and proline metabolism. The expression of SOD and APX, PSBA and PSBB was induced in the presence of H2O2 to alleviate the As damage to PS II and maintain photosynthetic activity. The role of H2O2 as a signaling molecule is shown in the protection of photosynthetic activity in rice from As toxicity through regulation on the activity and the expression of antioxidant enzymes.

Development and Comparative Evaluation of Endolysosomal Proximity Labeling-Based Proteomic Methods in Human iPSC-Derived Neurons.

Proximity-based in situ labeling techniques offer a unique way to capture both stable and transient protein-protein and protein-organelle interactions. Combining this technology with mass spectrometry (MS)-based proteomics allows us to obtain snapshots of molecular microenvironments with nanometer resolution, facilitating the discovery of complex and dynamic protein networks. However, a number of technical challenges still exist, such as interferences from endogenously biotinylated proteins and other highly abundant bystanders, how to select the proper controls to minimize false discoveries, and experimental variations among biological/technical replicates. Here, we developed a new method to capture the proteomic microenvironment of the neuronal endolysosomal network by knocking in (KI) an engineered ascorbate peroxidase (APEX) gene to the endogenous locus of lysosome-associated membrane protein 1 (LAMP1). We found that normalizing proximity labeling proteomics data to the endogenously biotinylated protein (PCCA) can greatly reduce variations and enable fair comparisons among different batches of APEX labeling and different APEX probes. We conducted a comparative evaluation between this KI-LAMP1-APEX method and our two overexpression LAMP1-APEX probes, achieving complementary coverage of both known and new lysosomal membrane and lysosomal-interacting proteins in human iPSC-derived neurons. To summarize, this study demonstrated new analytical tools to characterize lysosomal functions and microenvironment in human neurons and filled critical gaps in the field for designing and optimizing proximity labeling proteomic experiments.

Enteromorpha compressa extract induces anticancer activity through apoptosis and autophagy in oral cancer.

Marine algae are an auspicious source of innovative bioactive compounds containing possible therapeutic agents against mammalian cancers. However, the mechanism by which bioactive algal compounds exhibit anticancer activity against oral squamous cell carcinoma (OSCC) is scant. The main objective of the current study was to explore the properties of the Enteromorpha compressa solvent extracts that induced autophagy and apoptosis with reference to their potent phytochemical and antioxidant properties. The presence of bioactive compounds were confirmed by UV and FT-IR spectroscopy. The free radical scavenging activity were analyzed by evaluating H2O2, DPPH, superoxide and hydroxyl activity. The anticancer activities of the extracts were investigated by employing clonogenic and scratch assay. The apoptosis potential was evaluated by DAPI and MMP by Rh123 fluorescence assay. Moreover, the CAT, SOD, GPX, APX, and GR activities were measured. The autophagy potential was evaluated by LC3 puncta formation, acridine orange in addition to LysoTracker staining. The present investigation revealed that the methanolic extract of E. compressa elicited robust free radical scavenging activity that discerns its antiproliferative potency. Moreover, the methanolic algal extract boosted intrinsic apoptosis against OSCC by downregulating protective antioxidant enzymes. Furthermore, it also revealed induction of autophagy to promote cell death in oral cancer cells. The presence of novel bioactive compounds in E. compressa has uncovered possible therapeutic value against OSCC by modulating antioxidant defense system, apoptosis and autophagy that could be used to explore very competent algal candidates for the development of potential alternative anticancer drugs.

The ameliorative effects of exogenous inoculation of Piriformospora indica on molecular, biochemical and physiological parameters of Artemisia annua L. under arsenic stress condition.

Aim of the current study was to investigate the effect of exogenously inoculated root endophytic fungus, Piriformospora indica, on molecular, biochemical, morphological and physiological parameters of Artemisia annua L. treated with different concentrations (0, 50, 100 and 150 µmol/L) of arsenic (As) stress. As was significantly accumulated in the roots than shoots of P. indica-inoculated plants. As accumulation and immobilization in the roots is directly associated with the successful fungal colonization that restricts most of As as compared to the aerial parts. A total of 4.1, 11.2 and 25.6 mg/kg dry weight of As was accumulated in the roots of inoculated plants supplemented with 50, 100 and 150 µmol/L of As, respectively as shown by atomic absorption spectroscopy. P. indica showed significant tolerance in vitro to As toxicity even at high concentration. Furthermore, flavonoids, artemisinin and overall biomass were significantly increased in inoculated-stressed plants. Superoxide dismutase and peroxidase activities were increased 1.6 and 1.2 fold, respectively under 150 µmol/L stress in P. indica-colonized plants. Similar trend was followed by ascorbate peroxidase, catalase and glutathione reductase. Like that, phenolic acid and phenolic compounds showed a significant increase in colonized plants as compared to their respective control/un-colonize stressed plants. The real-time PCR revealed that transcriptional levels of artemisinin biosynthesis genes, isoprenoids, terpenes, flavonoids biosynthetic pathway genes and signal molecules were prominently enhanced in inoculated stressed plants than un-inoculated stressed plants.

Selenium toxicity stress-induced phenotypical, biochemical and physiological responses in rice plants: Characterization of symptoms and plant metabolic adjustment.

Selenium (Se) at low concentration is considered benefit element to plants. The range between optimal and toxic concentration of Se is narrow and varies among plant species. This study aimed to evaluate the phenotypic, physiological and biochemical responses of four rice genotypes (BRS Esmeralda, BRSMG Relâmpago, BRS Bonança and Bico Ganga) grown hydroponically treated with sodium selenate (1.5 mM L-1). Selenium treated plants showed a dramatically decrease of soluble proteins, chlorophylls, and carotenoids concentration, resulting in the visual symptoms of toxicity characterized as leaf chlorosis and necrosis. Selenium toxicity caused a decrease on shoot and root dry weight of rice plants. Excess Se increased the oxidative stress monitored by the levels of hydrogen peroxide and lipid peroxidation. The enzymatic antioxidant system (catalase, superoxide dismutase, and ascorbate peroxidase) increased in response to Se supply. Interestingly, primary metabolism compounds such as sucrose, total sugars, nitrate, ammonia and amino acids increased in Se-treated plants. The increase in these metabolites may indicate a defense mechanism for the osmotic readjustment of rice plants to mitigate the toxicity caused by Se. However, these metabolites were not effective to minimize the damages on phenotypic traits such as leaf chlorosis and reduced shoot and root dry weight in response to excess Se. Increased sugars profile combined with antioxidant enzymes activities can be an effective biomarkers to indicate stress induced by Se in rice plants. This study shows the physiological attributes that must be taken into account for success in the sustainable cultivation of rice in environments containing excess Se.

Effects of ethylene biosynthesis and signaling on oxidative stress and antioxidant defense system in Nelumbo nucifera G. under cadmium exposure.

Water contamination with cadmium (Cd) is a global environmental problem and its remediation becomes urgent. Phytoremediation using ornamental plants has attracted much attention for its advantages of cost-effectiveness and beautification of the environment. Nelumbo nucifera G. is a popular ornamental aquatic macrophyte with fast growth, large biomass, and high capacities for Cd accumulation and removal. However, information about Cd resistance and defense responses in N. nucifera is rather scarce, which restricts its large-scale utilization for phytoremediation. The phytohormone ethylene plays an important role in plant resistance to Cd stress, but the underlying mechanism remains unclear. In this study, we investigated morphophysiological responses of N. nucifera seedlings to Cd stress, and focused on the effects of ethylene on oxidative damage, Cd accumulation, and antioxidant defense system at the metabolic and transcript levels in leaves under Cd stress. Our results showed that Cd exposure led to leaf chlorosis and necrosis, coupled with an increase in contents of hydrogen peroxide, electrolyte leakage, and malondialdehyde, and decrease in chlorophyll content. Exogenous ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC) application intensified Cd-induced stress responses and Cd accumulation, and increased ethylene production by inducing ACC synthase (ACS) gene NnACS. Such enhanced ethylene emission inhibited catalase (CAT), ascorbate peroxidase (APX), and glutathione reductase (GR) activities, and modulated ascorbate (AsA) and glutathione (GSH) accumulation through transcriptional regulation of their respective metabolic genes. After ethylene action inhibitor silver thiosulfate (STS) supplementation, Cd-induced oxidative damage was abolished, and Cd content declined but still at a relatively high level. Blocking of ethylene perception by STS inhibited ethylene biosynthesis; enhanced CAT, APX, and GR activities and their transcript levels; increased AsA accumulation via inducing its biosynthetic genes; but reduced GSH content and NnGSH2 expression level. These results suggest that ethylene biosynthesis and signaling play an important role in N. nucifera response to Cd stress, and maintaining appropriate ethylene level and low ethylene sensitivity could improve its Cd tolerance via efficient antioxidant defenses.