Effect of exogenous catechin on alleviating O3 stress: The role of catechin-quinone in lipid peroxidation, salicylic acid, chlorophyll content, and antioxidant enzymes of Zamioculcas zamiifolia

Overcoming the challenge of invasive Parthenium hysterophorus management through integration of Aspergillus allahabadii (Eurotiales: Aspergillaceae) and Zygogramma bicolorata (Coleoptera: Chrysomelidae) as biocontrol agents

Parthenium hysterophorus is an invasive weed posing significant environmental challenges. This study explores the synergistic effects of the fungal strain Aspergillus allahabadii (P-Ph-13) and its interaction with the beetle Zygogramma bicolorata in controlling the weed. The combined action of A. allahabadii (P-Ph-13) and Z. bicolorata significantly suppressed the weed's germination and growth. Interaction with Z. bicolorata further boosted its effectiveness, decreasing seedling vigor by 78 % and increasing mortality by up to 42 % compared to the control group. Additionally, the interactive treatment severely disrupted the weed's physiological processes, causing extensive damage and ultimately leading to seedling death. These findings indicate that the synergistic effect of A. allahabadii and Z. bicolorata presents a promising strategy for managing Parthenium.

Recent research on the physicochemical properties and biological activities of quinones and their practical applications: a comprehensive review

Quinones represent a class of crude organic compounds ubiquitously distributed in nature. Their distinctive quinone-type structure confers upon them unique properties and applications. Quinones demonstrate significant biological activities, including antioxidant, antimicrobial, and antitumor properties. Additionally, they demonstrate noteworthy physicochemical characteristics, including excellent dyeing properties and stability. Given their diverse qualities, quinones hold significant promise for applications in industrial manufacturing, healthcare, and food production, thus garnering considerable attention in recent years. While there is a growing body of research on quinones, the existing literature falls short of providing a comprehensive review encompassing recent advancements in this field along with established knowledge. This paper offers a comprehensive review of research progress for quinones, encompassing structural classification, source synthesis, extraction methods, properties, functions, and specific applications. It serves as a reference and theoretical foundation for the further development and utilization of quinones.

Exploring bioluminescence in Aglaonema: Investigating Vibrio campbellii translocation and plant responses under CaCl₂ stimulation

The feasibility of creating light-emitting plants by immobilizing Vibrio campbellii RMT1 on the rhizospheric zone of Aglaonema sp. 'Banlangngoen' was investigated in depth, including bacteria translocation and plant response. Results from scanning electron microscope showed that an inorganic salt-containing medium affected the root. However, transmission electron microscope results displayed bacteria translocation through the root to the leaf and colonized in the cytosol of vascular tissues. Bacteria cell counts exhibited high colonization in the root zone, approximately 3.65 × 106 CFU/mL, resulting in a light-emitting intensity increase of 23.68-fold higher than the control after the first week. Nevertheless, light microscope revealed that inorganic salts in the culture medium led to enlarged air spaces, resulting in leaf and stalk withering. Notably, spraying plants with calcium chloride (CaCl2) solution effectively mitigated salt stress, activated luminescence, and facilitated bacterial movement from roots to leaves. Additionally, CaCl2 contributed to ongoing salinity reduction in the culture medium, as evidenced by reduced malondialdehyde levels, alongside increased indole-3-acetic acid and salicylic acid concentrations, indicating plant defense responses. The interaction between plants and luminescent bacteria demonstrated the potential for producing glowing plants following CaCl2 application, addressing salinity stress, enhancing luminescence, and maintaining plant growth.

Light-emitting plants development by inoculating of Vibrio campbellii RMT1 on the rhizospheric zone of Aglaonema cochinchinense

The concept of utilizing light-emitting plants (LEPs) as an alternative to traditional electricity-based lighting has garnered interest. However, challenges persist due to the need for genetic modification or chemical infusion in current LEPs. To address this, researchers have investigated the interaction between plants and luminous bacteria, specifically Vibrio campbellii, which can efficiently be translocated into Aglaonema cochinchinense tissues through the roots to produce LEPs. This study concentrated on examining light intensity and enhancing luminescence by growing plants and spraying them with various media substances. The results indicated that V. campbellii successfully translocated into the plant tissue via the root system and accumulated a high number of bacteria in the stems, approximately 8.46 × 104 CFU/g, resulting in a light-emitting intensity increase of 12.13-fold at 48 h, and then decreased after 30 h. Interestingly, luminescence stimulation by spraying the growth medium managed to induce the highest light emission, reaching 14.84-fold at 48 h, though it had some negative effects on the plant. Conversely, spraying plants with CaCl2 on the leaves prolonged light emission for a longer duration (42 h after spraying) and had a positive effect on plant health, it maintained ion homeostasis and reduced-MDA content. This study highlights the potential of using V. campbellii and CaCl2 spraying for the future development of practical light-emitting plants.

Tea-Derived Polyphenols Enhance Drought Resistance of Tea Plants (Camellia sinensis) by Alleviating Jasmonate-Isoleucine Pathway and Flavonoid Metabolism Flow

Extreme drought weather has occurred frequently in recent years, resulting in serious yield loss in tea plantations. The study of drought in tea plantations is becoming more and more intensive, but there are fewer studies on drought-resistant measures applied in actual production. Therefore, in this study, we investigated the effect of exogenous tea polyphenols on the drought resistance of tea plant by pouring 100 mg·L-1 of exogenous tea polyphenols into the root under drought. The exogenous tea polyphenols were able to promote the closure of stomata and reduce water loss from leaves under drought stress. Drought-induced malondialdehyde (MDA) accumulation in tea leaves and roots was also significantly reduced by exogenous tea polyphenols. Combined transcriptomic and metabolomic analyses showed that exogenous tea polyphenols regulated the abnormal responses of photosynthetic and energy metabolism in leaves under drought conditions and alleviated sphingolipid metabolism, arginine metabolism, and glutathione metabolism in the root system, which enhanced the drought resistance of tea seedlings. Exogenous tea polyphenols induced jasmonic acid-isoleucine (JA-ILE) accumulation in the root system, and the jasmonic acid-isoleucine synthetase gene (TEA028623), jasmonic acid ZIM structural domain proteins (JAMs) synthesis genes (novel.22237, TEA001821), and the transcription factor MYC2 (TEA014288, TEA005840) were significantly up-regulated. Meanwhile, the flavonoid metabolic flow was significantly altered in the root; for example, the content of EGCG, ECG, and EGC was significantly increased. Thus, exogenous tea polyphenols enhance the drought resistance of tea plants through multiple pathways.

Octanal enhances disease resistance in postharvest citrus fruit by the biosynthesis and metabolism of aromatic amino acids

Octanal was found to be able to reduce green mold incidence in citrus fruit by a defense response mechanism. However, the underlying mechanism remains largely unclear. Herein, the metabolomics, RNA-seq and biochemical analyses were integrated to explore the effect of octanal on disease resistance in harvested citrus fruit. Results showed that octanal fumigation at 40 μL L-1 was effective in controlling citrus green mold. Metabolomics analysis showed that octanal mainly led to the accumulation of some plant hormones including methyl jasmonate, abscisic acid, indole-3-butyric acid, indoleacetic acid (IAA), salicylic acid, and gibberellic acid and many phenylpropanoid metabolites including cinnamyl alcohol, hesperidin, dihydrokaempferol, vanillin, quercetin-3-O-malonylglucoside, curcumin, naringin, chrysin, coniferin, calycosin-7-O-β-D-glucoside, trans-cinnamaldehyde, and 4',5,7-trihydroxy-3,6-dimethoxyflavone. Particularly, IAA and hesperidin were dramatically accumulated in the peel, which might be the contributors to the resistance response. Additionally, transcriptome analysis showed that octanal greatly activated the biosynthesis and metabolism of aromatic amino acids. This was further verified by the accumulation of some metabolites (shikimic acid, tryptophan, tyrosine, phenylalanine, IAA, total phenolics, flavonoids and lignin), increase in some enzyme activities (phenylalanine ammonia-lyase, tyrosine ammonia-lyase, 4-coumarate CoA ligase, cinnamic acid 4-hydroxylase, polyphenol oxidase, and peroxidase), up-regulation of some genes (tryptophan pyruvate aminotransferase, aldehyde dehydrogenase, shikimate kinase and shikimate dehydrogenase) expressions and molecular docking results. Thus, these results indicate that octanal is an efficient strategy for the control of postharvest green mold by triggering the defense response in citrus fruit.

In vitro digestion and colonic fermentation of phenolic compounds and their antioxidant potential in Australian beach-cast seaweeds

Beach-cast seaweed has recently garnered attention for its nutrient-rich composition, including proteins, carbohydrates, vitamins, minerals, and phytochemicals. This study focuses on the phenolic content and antioxidant potential of five Australian beach-cast seaweed species during in vitro digestion and colonic fermentation. The bioaccessibility of the selected phenolic compounds was estimated and short chain fatty acids (SCFAs) production was determined. Cystophora sp., showed a notable increase in phenolic content (23.1 mg GAE/g) and antioxidant capacity (0.42 mg CE/g) during the intestinal and gastric phases of in vitro digestion. Durvillaea sp. demonstrated a significant release of flavonoids (0.35 mg QE/g), while Phyllosphora comosa released high levels of tannins (0.72 mg CE/g) during the intestinal phase. During colonic fermentation, P. comosa released the highest levels of phenolic compounds (4.3 mg GAE/g) after 2 h, followed by an increase in flavonoids (0.15 mg QE/g), tannins (0.07 mg CE/g), and antioxidant activity (DPPH: 0.12 mg CE/g; FRAP: 0.61 mg CE/g) after 4 h. Moreover, P. comosa released a considerable amount of phenolic compounds during both in vitro digestion and colonic fermentation. All species consistently released phenolic compounds throughout the study. Phloroglucinol, gallic acid, and protocatechuic acid were identified as the most bioaccessible phenolic compounds in all five Australian beach-cast seaweeds in the in vitro digestion. Nevertheless, compound levels declined during the colonic fermentation phase due to decomposition and fermentation by gut microbiota. With regard to SCFAs, P. comosa displayed elevated levels of acetic (0.51 mmol/L) and propionic acid (0.36 mmol/L) at 2 h, while Durvillaea sp. showed increased butyric (0.42 mmol/L) and valeric (0.26 mmol/L) production acid after 8 h. These findings suggest that seaweed such as Cystophora sp., Durvillaea sp., and P. comosa are promising candidates for food fortification or nutraceutical applications, given their rich phenolic content and antioxidant properties that potentially offer gut health benefits.

Elevated tropospheric ozone and crop production: potential negative effects and plant defense mechanisms

Ozone (O3) levels on Earth are increasing because of anthropogenic activities and natural processes. Ozone enters plants through the leaves, leading to the overgeneration of reactive oxygen species (ROS) in the mesophyll and guard cell walls. ROS can damage chloroplast ultrastructure and block photosynthetic electron transport. Ozone can lead to stomatal closure and alter stomatal conductance, thereby hindering carbon dioxide (CO2) fixation. Ozone-induced leaf chlorosis is common. All of these factors lead to a reduction in photosynthesis under O3 stress. Long-term exposure to high concentrations of O3 disrupts plant physiological processes, including water and nutrient uptake, respiration, and translocation of assimilates and metabolites. As a result, plant growth and reproductive performance are negatively affected. Thus, reduction in crop yield and deterioration of crop quality are the greatest effects of O3 stress on plants. Increased rates of hydrogen peroxide accumulation, lipid peroxidation, and ion leakage are the common indicators of oxidative damage in plants exposed to O3 stress. Ozone disrupts the antioxidant defense system of plants by disturbing enzymatic activity and non-enzymatic antioxidant content. Improving photosynthetic pathways, various physiological processes, antioxidant defense, and phytohormone regulation, which can be achieved through various approaches, have been reported as vital strategies for improving O3 stress tolerance in plants. In plants, O3 stress can be mitigated in several ways. However, improvements in crop management practices, CO2 fertilization, using chemical elicitors, nutrient management, and the selection of tolerant crop varieties have been documented to mitigate O3 stress in different plant species. In this review, the responses of O3-exposed plants are summarized, and different mitigation strategies to decrease O3 stress-induced damage and crop losses are discussed. Further research should be conducted to determine methods to mitigate crop loss, enhance plant antioxidant defenses, modify physiological characteristics, and apply protectants.

Research progress in the molecular mechanism of ferroptosis in Parkinson's disease and regulation by natural plant products

Parkinson's disease (PD) is the second most prevalent neurodegenerative disorder of the central nervous system after Alzheimer's disease. The current understanding of PD focuses mainly on the loss of dopamine neurons in the substantia nigra region of the midbrain, which is attributed to factors such as oxidative stress, alpha-synuclein aggregation, neuroinflammation, and mitochondrial dysfunction. These factors together contribute to the PD phenotype. Recent studies on PD pathology have introduced a new form of cell death known as ferroptosis. Pathological changes closely linked with ferroptosis have been seen in the brain tissues of PD patients, including alterations in iron metabolism, lipid peroxidation, and increased levels of reactive oxygen species. Preclinical research has demonstrated the neuroprotective qualities of certain iron chelators, antioxidants, Fer-1, and conditioners in Parkinson's disease. Natural plant products have shown significant potential in balancing ferroptosis-related factors and adjusting their expression levels. Therefore, it is vital to understand the mechanisms by which natural plant products inhibit ferroptosis and relieve PD symptoms. This review provides a comprehensive look at ferroptosis, its role in PD pathology, and the mechanisms underlying the therapeutic effects of natural plant products focused on ferroptosis. The insights from this review can serve as useful references for future research on novel ferroptosis inhibitors and lead compounds for PD treatment.

Possibility to Apply Strontium Aluminate to Produce Light-Emitting Plants: Efficiency and Safety

Light-emitting plants (LEPs) provides light in areas without electricity. The phosphorescent compound was used as a lighting material for LEP development. However, using the phosphorescent compound for LEPs development required optimization and phytotoxicity evaluation. Strontium aluminate (SrAl2 O4 ) is a phosphorescent compound that can glow for a long time and is easily recharged by visible light. In this study, using SrAl2 O4 to develop LEPs was evaluated. Additionally, plant stress under SrAl2 O4 was investigated. Metabolomic analysis can explain the possible mechanism of plants' stress under SrAl2 O4 . After, injecting 3 mL of 5 % (w/v) SrAl2 O4 products 1, 2, and 3 into the stem of Ipomoea aquatica, the result showed that SrAl2 O4 products 2 and 3 caused oxidative stress. The metabolomic analysis also indicated that I. aquatica responded to SrAl2 O4 product 1 by increasing pipecolic acid and salicylic acid, while I. aquatica injected with SrAl2 O4 products 2 and 3 showed a decrease in salicylic acid around 0.005 and 0.061-fold, respectively, compared to control plants. and an excess accumulation of MDA around 10.00-12.00 μmol g-1 FW. A 15 % concentration of SrAl2 O4 can be used for LEPs development, enabling photoemission 18-fold for 50 min. SrAl2 O4 product 1 has the potential to be a material for LEPs.

Knockout of amino acid transporter gene OsLHT1 accelerates leaf senescence and enhances resistance to rice blast fungus

Plant amino acid transporters (AATs) regulate not only long-distance transport and reallocation of nitrogen (N) from source to sink organs, but also amount of amino acids in leaves hijacked by invaded pathogens. However, the function of AATs in plant defense responses to pathogen infection remains unknown. In this study, we found that rice amino acid transporter gene OsLHT1 was expressed in leaves and up-regulated by maturing, N starvation and inoculation of blast fungus Magnaporthe oryzae. Knockout of OsLHT1 resulted in development stage- and N supply-dependent premature senescence of leaves at vegetative growth stage. In comparison to wild type, Oslht1 mutant lines showed sustained rusty red spots on fully mature leaf blades irrespective of N supply levels. Notably, no relationship between the severity of leaf rusty red spots and concentration of total N or amino acids was found in Oslht1 mutants at different developmental stages. Disruption of OsLHT1 altered transport and metabolism of amino acids and biosynthesis of flavones and flavonoids, enhanced expression of jasmonic acid- and salicylic acid-related defense genes and production of jasmonic acid and salicylic acid, accumulation of reactive oxygen species. OsLHT1 inactivation dramatically prevented the leaf invasion of M. oryzae, the hemi-biotrophic ascomycete fungus. Overall, these results establish a module connecting the activity of amino acid transporter with leaf metabolism and defense to rice blast fungus.

An Instant Underwater Tissue Adhesive Composed of Catechin-Chondroitin Sulfate and Cholesterol-Polyethyleneimine

Due to the safety issue and poor underwater adhesion of current commercially available bioadhesives, they are hard to apply to in vivo physiological environments and more diverse medical use conditions. In this study, a novel and facile bioadhesive for underwater medical applications are designed based on the coacervation of electrostatic interactions and hydrophobic interactions, with the introduction of catechin as a provider of catechol moieties for adhesion to surrounding tissues. The orange-colored bio-adhesive, named PcC, is generated within seconds by mixing catechin-modified chondroitin sulfate and cholesterol chloroformate-modified polyethyleneimine with agitation. In vitro mechanical measurements prove that this novel PcC bio-adhesive is superior in underwater adhesion performance when applied to cartilage. Animal experiments in a rat mastectomy model and rat cartilage graft implantation model demonstrate its potential for diverse medical purposes, such as closing surgical incisions, reducing the formation of seroma, and tissue adhesive applied in orthopedic or cartilage surgery.

Bacillus thuringiensis A1 improve phenol tolerance and phytoextraction by Acorus calamus L

Phenol, as a very toxic pollutant, exists widely in rivers in China. To explore the effect of bacterial augmentation on phytoremediation of phenol by Acorus calamus L., some plant growth and physiological parameters and percent removal of phenol were determined in hydroponics containing phenol with addition of Bacillus thuringiensis A1. The A. calamus L. and B. thuringiensis A1 consortium increased the growth rate of plant height, chlorophyll content, the activity of superoxide dismutase (SOD) and peroxidase (POD) in A. calamus L. 10.00-36.54%, 0.62 - 22.15%, 3.94 - 11.25% and 1.37-10.50% respectively compared with single plant treatments at same phenol concentrations. However, the addition of B. thuringiensis A1 decreased the content of malondialdehyde (MDA) and relative electrical conductivity (REC) in A. calamus L. 12.99-23.66% and 8.38-29.98% respectively compared with single plant treatments. The removal efficiency of phenol (increased from 1.56% to 13.78%) by the A. calamus L. and B. thuringiensis A1 consortium was higher than the removal efficiency of phenol of the independent A. calamus L. system. In conclusion, the addition of B. thuringiensis A1 alleviated phenol stress to A. calamus L and enhanced phenol removal due to phenol removal by bacterial augmentation.Novelty statementThe addition of B. thuringiensis A1 alleviated phenol stress to A. calamus L. and enhanced phenol removal due to phenol removal by bacterial augmentation.

Mechanisms of ozone responses in sensitive and tolerant mungbean cultivars

Ozone (O 3) is one of the major air pollutants, with negative impacts on human health, vegetation and agricultural production. It affects plants by reducing green leaf area and leading to necrosis, lesions and chlorosis, resulting in yield loss. Four mungbean cultivars were used to study O 3 sensitivity under elevated O 3 concentrations in the range of 70-100 ppb in an O 3 open-top chamber during the growing season. Based on O 3 response mechanisms, we classified mungbean cultivars into two groups: (1) O 3 -sensitive cultivars (Chainat 3 and 4) and (2) O 3 -tolerant cultivars (Chainat 84-1-1 and Kampangsan 2). The most O 3 -sensitive cultivars (Chainat 4) had the highest visible injury symptoms and the lowest in plant biomass. This evidence was due to Chainat 4 had lower ascorbic acid, indole acetic biosynthesis protein, defence related protein related to antioxidant systems, attribute to higher H 2 O 2 accumulation and an increase in salicylic acid contents. In contrast to the most O 3 -tolerant cultivars (Chainat 84-1-1) which had higher ascorbic acid levels, an upregulation of defence related protein, especially ascorbic acid biosynthesis and regenerate, indole acetic acid and jasmonic acid biosynthesis protein resulting in balanced H 2 O 2 levels, lower salicylic acid accumulation and little visible injury under elevated O 3 concentrations. Therefore, we conclude that the increased abundance of indole acetic acid, antioxidant related proteins facilitating stomata physiology in O 3 -tolerant under O 3 stress. This is the first report of the responses of mungbean cultivars in Thailand to elevated O 3 concentrations, facilitating the selection of suitable cultivars and the biomonitoring of O 3 levels.

Research progress on the response of tea catechins to drought stress

Drought stress (DS) is the most important abiotic stress affecting yield and quality of tea worldwide. DS causes oxidative stress to cells due to the accumulation of reactive oxygen species (ROS). As non-enzymatic antioxidants, tea catechins can scavenge excess ROS in response to DS. Further, catechin accumulation contributes to the formation of oxidative polymerization products (e.g. theaflavins and thearubigins) that improve the quality of black tea. However, there are no systematic reports on the response of tea catechins to DS. First, we reviewed the available literature on the response of tea plants to DS. Second, we summarized the current knowledge of ROS production in tea leaves under DS and typical antioxidant response mechanisms. Third, we conducted a detailed review of the changes in catechin levels in tea under different drought conditions. We found that the total amounts of catechin and o-quinone increased under DS conditions. We propose that the possible mechanisms underlying tea catechin accumulation under DS conditions include (i) autotrophic formation of o-quinone, (ii) polymerization of proanthocyanidins that directly scavenge excess ROS, and (iii) formation of metal ion complexes and by influencing the antioxidant systems that indirectly eliminate excess ROS. Finally, we discuss ways of potentially improving black tea quality using drought before picking in the summer/fall dry season. In summary, we mainly discuss the antioxidant mechanisms of tea catechins under DS and the possibility of using drought to improve black tea quality. Our review provides a theoretical basis for the production of high-quality black tea under DS conditions. © 2021 Society of Chemical Industry.

Liquiritoside Alleviated Pb Induced Stress in Brassica rapa subsp. Parachinensis: Modulations in Glucosinolate Content and Some Physiochemical Attributes

Current research was conducted to explore the effects of liquiritoside on the growth and physiochemical features of Chinese flowering cabbage (Brassica rapa subsp. parachinensis) under lead (Pb) stress. Lead stressed B. rapa plants exhibited decreased growth parameters, chlorophyll, and carotenoid contents. Moreover, Pb toxicity escalated the synthesis of malondialdehyde (MDA), hydrogen peroxide (H2O2), flavonoids, phenolics, and proline in treated plants. Nevertheless, foliar application of liquiritoside mitigated Pb toxicity by decreasing oxidative stress by reducing cysteine, H2O2, and MDA contents in applied plants. Liquiritoside significantly increased plant height, shoot fresh weight and dry weight, number of leaves, and marketable value of Chinese flowering cabbage plants exposed to Pb toxicity. This biotic elicitor also enhanced the proline, glutathione, total phenolics, and flavonoid contents in Chinese flowering cabbage plants exposed to Pb stress compared with the control. Additionally, total glucosinolate content, phytochelatins (PCs), and non-protein thiols were effectively increased in plants grown under Pb regimes compared with the control plants. Overall, foliar application of liquiritoside can markedly alleviate Pb stress by restricting Pb translocation in Chinese flowering cabbage.

Membrane dynamics during individual and combined abiotic stresses in plants and tools to study the same

The plasma membrane (PM) is possibly the most diverse biological membrane of plant cells; it separates and guards the cell against its external environment. It has an extremely complex structure comprising a mosaic of lipids and proteins. The PM lipids are responsible for maintaining fluidity, permeability and integrity of the membrane and also influence the functioning of membrane proteins. However, the PM is the primary target of environmental stress, which affects its composition, conformation and properties, thereby disturbing the cellular homeostasis. Maintenance of integrity and fluidity of the PM is a prerequisite for ensuring the survival of plants during adverse environmental conditions. The ability of plants to remodel membrane lipid and protein composition plays a crucial role in adaptation towards varying abiotic environmental cues, including high or low temperature, drought, salinity and heavy metals stress. The dynamic changes in lipid composition affect the functioning of membrane transporters and ultimately regulate the physical properties of the membrane. Plant membrane-transport systems play a significant role in stress adaptation by cooperating with the membrane lipidome to maintain the membrane integrity under stressful conditions. The present review provides a holistic view of stress responses and adaptations in plants, especially the changes in the lipidome and proteome of PM under individual or combined abiotic stresses, which cause alterations in the activity of membrane transporters and modifies the fluidity of the PM. The tools to study the varying lipidome and proteome of the PM are also discussed.

Cardiorespiratory Effects of Indoor Ozone Exposure Associated with Changes in Metabolic Profiles among Children: A Repeated-Measure Panel Study

Ozone is one of the major gaseous pollutants associated with short-term adverse cardiopulmonary effects, even at concentrations below the current indoor air quality limits. However, the underlying biological mechanisms of cardiorespiratory changes with exposure to ozone remain unclear. To further explore molecular linkages between indoor ozone exposure and relevant cardiorespiratory effects, a repeated-measure panel study including 46 schoolchildren was conducted and real-time exposure measurements including ozone were performed inside classrooms every weekday during the study period. Repeated health measurements and urine sample collection were conducted in each participant. Ultra-high-performance liquid chromatography/tandem mass spectrometry and meet-in-metabolite approach were used in metabolomics analysis. Methods including mixed-effect models were adopted to identify metabolites associated with ozone exposure or health indices. Nine metabolites were found to be associated with ozone after mixed-effect model analysis, which are mainly involved in amino acid and bile acid metabolism. Boys may have a greater decrease in bile acid and RNA related metabolites. Four of the nine ozone-related metabolites were also associated with cardiorespiratory function indices. Furthermore, 26.67% of the positive association between ozone and heart rate was mediated by cholestane-3,7,12,25-tetrol-3-glucuronide. Exposure to ozone below the current indoor standards was associated with the deteriorated cardiovascular function by disturbing bile acid and endogenous nitric oxide-related oxidation and inflammation, and associated with the exacerbated airway inflammation by reducing GPx-related anti-oxidation. The results provide metabolic evidence of the cardiorespiratory effects of indoor ozone exposure. Indoor ozone pollution should be controlled further, and more attention should be paid to preventing its adverse health effects, especially in children.

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Indoor O₃ exposure far below the indoor air quality limits disturbed amino acid and bile acid metabolism of children

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Exposure to indoor O₃ at low concentrations was associated with the deteriorated HRV, BP by affecting bile acid- and endogenous NO-related oxidation and inflammation

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Exposure to indoor O₃ at low concentrations was associated with the aggravated airway inflammation by reducing GPx-related anti-oxidation

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The cardiorespiratory effects of low-level ozone exposure indoors in children require additional attention

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Indoor ozone pollution should be controlled further and the current indoor ozone standards should be revised

Catechins as Model Bioactive Compounds for Biomedical Applications

Research regarding polyphenols has gained prominence over the years because of their potential as pharmacological nutrients. Most polyphenols are flavanols, commonly known as catechins, which are present in high amounts in green tea. Catechins are promising candidates in the field of biomedicine. The health benefits of catechins, notably their antioxidant effects, are related to their chemical structure and the total number of hydroxyl groups. In addition, catechins possess strong activities against several pathogens, including bacteria, viruses, parasites, and fungi. One major limitation of these compounds is low bioavailability. Catechins are poorly absorbed by intestinal barriers. Some protective mechanisms may be required to maintain or even increase the stability and bioavailability of these molecules within living organisms. Moreover, novel delivery systems, such as scaffolds, fibers, sponges, and capsules, have been proposed. This review focuses on the unique structures and bioactive properties of catechins and their role in inflammatory responses as well as provides a perspective on their use in future human health applications.

Integrated proteomics, metabolomics and physiological analyses for dissecting the toxic effects of halosulfuron-methyl on soybean seedlings (Glycine max merr.)

Halosulfuron methyl (HSM) is a herbicide widely used to control sedge and broad-leaved weeds during crop production, but its environmental residue may damage non-target crops. Here, proteomics and metabolomics methods were used to explore the phytotoxicity mechanisms of HSM against soybean (Glycine max Merr.). Soybean seedlings were exposed to 0.01, 0.05 and 0.5 mg/L HSM for 8 d. The HSM applications significantly reduced chlorophyll and carotenoid contents in HSM-treated seedlings. Additionally, chlorophyll a fluorescence was seriously affected. The glutathione, hydrogen peroxide and malondialdehyde contents, as well as antioxidant enzyme activities, significantly increased in seedlings exposed to HSM. Furthermore, five enzymes involved in the tricarboxylic acid (TCA) cycle, α-ketoglutarate dehydrogenase, isocitrate dehydrogenase, aconitase, malic dehydrogenase and succinate dehydrogenase, were inhibited to varying degrees in HSM-treated seedlings compared with controls. Proteomics results showed multiple differentially abundant proteins involved in chlorophyll synthesis, photosystem processes and chloroplast ATP synthetase were down-regulated. Metabolomics analyses revealed that metabolites involved in the TCA cycle decreased significantly. Moreover, metabolites and proteins related to reactive oxygen species detoxification accumulated. In conclusion, the phytotoxicity mechanisms of HSM against soybean mainly act by damaging the photosynthetic machinery, inhibiting chlorophyll synthesis, interrupting the TCA cycle and causing oxidative stress. These results provide new insights into the toxicity mechanisms of sulfonylurea herbicides against non-target crops.

Enhancing the atrazine tolerance of Pennisetum americanum (L.) K. Schum by inoculating with indole-3-acetic acid producing strain Pseudomonas chlororaphis PAS18

Atrazine as a kind of herbicide could cause damage to the sensitive plants. Though plant growth promoting rhizobacteria (PGPR) have been proven with the potential to enhance the resistance of plants against various abiotic stresses, whether it could alleviate phytotoxicity caused by atrazine is sill unclear. In present study, the effects of strain Pseudomonas chlororaphis PAS18, a kind of PGPR enable to produce indole-3-acetic acid (IAA), on the growth and physiological responses of Pennisetum americanum (L.) K.Schum seedlings were investigated under three different levels (0, 20 and 100 mg kg^-1) of atrazine in pot experiment. The results suggest that strain PAS18 could alleviate the growth and physiological interference caused by 20 mg kg^-1 of atrazine. Physiological analysis showed strain PAS18 could further decrease the damaged extent of photosystem II, superoxide radical level and malondialdehyde content of test plant via up-regulating psbA expression, enhancing superoxide dismutase activity and reducing atrazine accumulation in the test plant. Moreover, ion flux measurements suggest that IAA could alleviate the Ca²⁺ exflux state of the test plant which caused by atrazine stress. Hence, it is plausible that strain PAS18 could alleviate atrazine-induced stress to P. americanum by enhancing the photosystem II repair and antioxidant defense ability as well as balancing the Ca²⁺ flux.

Effect of exogenous catechin and salicylic acid on rice productivity under ozone stress: the role of chlorophyll contents, lipid peroxidation, and antioxidant enzymes

Increasing ozone concentration is one of the oxidative stresses that affects rice yield loss in many countries. Catechin and salicylic acid were proposed as tools for alleviating oxidative stress in plants, but their roles in protecting rice productivity under ozone stress still remained unknown. We investigated the mechanism of catechin and salicylic acid on rice under ozone stress at the vegetative stage and at the reproductive stage. Rice was sprayed with catechin and salicylic acid before exposure to ozone in the range of 100-150 ppb (8 h day^-1). Ozone and salicylic acid led to a decrease in chlorophyll contents, magnesium contents, and stomatal conductance. This evidence led to a decrease in rice productivity and quality. In contrast, under rice + catechin, both ambient air and elevated ozone conditions had to higher rice productivity and quality than under rice alone and rice + salicylic acid conditions. Catechin could mitigate ozone stress in rice plants through maintaining chlorophyll contents, magnesium contents, and stomatal conductance. Moreover, catechin could induce an unregulation of ascorbate peroxidase, and catalase genes led to increasing their antioxidant enzyme activity. Increasing of antioxidant enzyme activity under rice + ozone + catechin conditions attributed to lower lipid peroxidation than under rice + ozone especially at vegetative stage. This study confirmed that catechin, which is naturally found in tea leaves, could be used as an ozone protectant. The protective role of catechin on chlorophyll contents and antioxidant systems at the vegetative stage attributed to maintaining rice yield under ozone stress. Graphical abstract.

Tianma Gouteng granules decreases the susceptibility of Parkinson's disease by inhibiting ALOX15-mediated lipid peroxidation

ETHNOPHARMACOLOGICAL RELEVANCE

Tianma Gouteng granules (TG), a clinical prescription of traditional Chinese medicine, has been clinically applied to treat Parkinson's disease (PD) in combination with Madopar, as included in the Chinese Pharmacopoeia (2015). TG has the potential to decrease the susceptibility of PD pharmacologically, however the mechanisms need detailed demonstration.

AIM OF THE STUDY

To evaluate the pharmacological activities, as well as the possible mechanism of TG in diverse models of PD.

MATERIALS AND METHODS

6-OHDA-treated rats, MPTP-treated mice, and α-synuclein A53T overexpressed mice, were utilized as PD animal models. Rotarod, locomotor activity, inclined plane and traction tests were used for behavioral assessment. Immunohistochemistry was used for tyrosine hydrolase determination. Western blot were conducted for detection of 4-HNE and 15-lipoxygenase-1 (ALOX15). The interactions of ALOX15 with the components in TG were predicted by molecular docking approach.

RESULTS

Lipid peroxidation was involved in dopaminergic neuron damage in 6-OHDA-induced rat models. In MPTP-treated mice, the inhibition of lipid peroxidation improved behavioral and pathological symptoms of PD. The lipid peroxidation-related protein, ALOX15 was found to be the key factor in PD process in diverse PD models including 6-OHDA-treated rats, MPTP-treated mice, and α-synuclein A53T overexpressed mice. TG treatment significantly relieved behavioral and pathological symptoms of MPTP-induced PD mouse models with a potential mechanism of alleviating ALOX15-induced lipid peroxidation. Moreover, the results of molecular docking analysis show that compounds in TG might have interactions with ALOX15.

CONCLUSIONS

TG effectively improved the behavioral and dopaminergic neuron damage in diverse PD models. The mechanism of this action may be related to the direct inhibition of ALOX15 and the relief of lipid peroxidation.

Identification and distribution of a single nucleotide polymorphism responsible for the catechin content in tea plants

Catechins are the predominant products in tea plants and have essential functions for both plants and humans. Several genes encoding the enzymes regulating catechin biosynthesis have been identified, and the identification of single nucleotide polymorphisms (SNPs) resulting in nonsynonymous mutations within these genes can be used to establish a functional link to catechin content. Therefore, the transcriptomes of two parents and four filial offspring were sequenced using next-generation sequencing technology and aligned to the reference genome to enable SNP mining. Subsequently, 176 tea plant accessions were genotyped based on candidate SNPs using kompetitive allele-specific polymerase chain reaction (KASP). The catechin contents of these samples were characterized by high-performance liquid chromatography (HPLC), and analysis of variance (ANOVA) was subsequently performed to determine the relationship between genotypes and catechin content. As a result of these efforts, a SNP within the chalcone synthase (CHS) gene was shown to be functionally associated with catechin content. Furthermore, the geographical and interspecific distribution of this SNP was investigated. Collectively, these results will contribute to the early evaluation of tea plants and serve as a rapid tool for accelerating targeted efforts in tea breeding.

Online coupling of the Ussing chamber, solid-phase extraction and high-performance liquid chromatography for screening and analysis of active constituents of traditional Chinese medicines

A semi-automated online platform was established successfully for preliminary screening of potential active flavonoids of traditional Chinese medicines (TCMs) in multicomponent system. Online coupling of the in vitro intestinal absorption model, solid phase extraction (SPE) and high-performance liquid chromatography (HPLC) was actualized at the first time. The Ussing chamber model was selected to absorb the constituents of TCMs. A mini chromatographic column filled with C18 was used as a SPE column for online enrichment of flavonoids. HPLC was applied to analyze the constituents screened by platform. With the use of rutin as a model flavonoid, the specifications of SPE column, eluting solvent, elution time and flow rate of eluent were systematically investigated to optimize online system. Under the optimal conditions, the linear range of rutin was 0.125-368 µg/mL with the correlation coefficient (R²) greater than 0.9947. The limit of detection (LOD) was as low as 0.0500 µg/mL and the limit of quantification (LOQ) was 0.125 µg/mL. The intra-day relative standard deviation (RSD) and inter-day RSD was 2.5% and 3.8%, respectively. The recoveries of rutin in the intestinal absorption samples ranged from 93.2% to 94.0%. Finally, the online system was applied to screen the potential active flavonoids of Scutellaria baicalensis Georgi (Huangqin, HQ) and Polygoni Cuspidati Rhizoma et Radix (Huzhang, HZ). A total of 14 flavonoids of these two TCMs were identified by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), and 12 flavonoids of them were screened as the potential active components by online Ussing chamber-SPE-HPLC. In comparison with offline method and gavage in rats, the online system can screen the active constituents from TCMs more accurately and completely. The results demonstrated that the online system was reliable and sufficiently accurate for screening and determination of the potential active flavonoids of TCMs in multicomponent system.