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Abstract Background Phosphorus is a macronutrient necessary for plant growth and development and its availability and efficient use affect crop yields. Leaves are the largest tissue that uses phosphorus in plants, and membrane phospholipids are the main source of cellular phosphorus usage. Results Here we identify a key process for plant cellular phosphorus recycling mediated by membrane phospholipid hydrolysis during leaf senescence. Our results indicate that over 90% of lipid phosphorus, accounting for more than one-third of total cellular phosphorus, is recycled from senescent leaves before falling off the plants. Nonspecific phospholipase C4 (NPC4) and phospholipase Dζ2 (PLDζ2) are highly induced during leaf senescence, and knockouts of PLDζ2 and NPC4 decrease the loss of membrane phospholipids and delay leaf senescence. Conversely, overexpression of PLDζ2 and NPC4 accelerates the loss of phospholipids and leaf senescence, promoting phosphorus remobilization from senescent leaves to young tissues and plant growth. We also show that this phosphorus recycling process in senescent leaves mediated by membrane phospholipid hydrolysis is conserved in plants. Conclusions These results indicate that PLDζ2- and NPC4-mediated membrane phospholipid hydrolysis promotes phosphorus remobilization from senescent leaves to growing tissues and that the phospholipid hydrolysis-mediated phosphorus recycling improves phosphorus use efficiency in plants.

The present study designed and prepared a novel platinum alloy system Pt-xAu-5Ni (x = 0, 2, 5, wt.%) with high strength and good electrical resistivity. The mechanical, electrical properties and related microstructure during the cold deformation and subsequent aging process were investigated. The cold-deformed Pt–5Ni alloy obtained the yield strength of 581 MPa, the ultimate tensile strength of 828 MPa, the hardness of 283 HV, and the electrical resistivity of 23.9 μΩ⋅cm. The subsequent aging process and the Au addition into Pt–5Ni alloy were found to both enhance the mechanical properties. Therefore, with the dual strengthening effect of the subsequent aging and the Au addition, Pt–5Au–5Ni alloy achieved the high yield strength of 889 MPa, the high ultimate tensile strength of 1117 MPa, the high hardness of 361 HV with the electrical resistivity of 26.7 μΩ⋅cm. The precipitation of L12-type Pt3Ni nanoparticles and L11-type CSRO dominated the age-strengthening behavior of Pt–2Au–5Ni and Pt–5Au–5Ni alloys after cold deformation. The Au addition refined the grains via the experimental observations, and predictably favored the L12-type Pt3Ni nanoprecipitation based on the thermodynamical calculations, thus the Au addition effectively strengthened Pt–5Ni alloy. This study provides a novel platinum alloy system with excellent mechanical and electrical properties, which has potential application in the electrical contact field.

Abstract Camelina neglecta is a new diploid Brassicaceae species, which has great research value because of its close relationship with the hexaploid oilseed crop Camelina sativa. Here, we report a chromosome-level assembly of C. neglecta with a total length of 210 Mb. By adopting PacBio sequencing and Hi-C technology, the C. neglecta genome was assembled into 6 chromosomes with scaffold N50 of 29.62 Mb. C. neglecta has undergone the whole-genome triplication (γ) shared among eudicots and two whole-genome duplications (α and β) shared by crucifers, but it has not undergone a specific whole-genome duplication event. By synteny analysis between C. neglecta and C. sativa, we successfully used the method of calculating Ks to distinguish the three subgenomes of C. sativa and determined that C. neglecta was closest to the first subgenome (SG1) of C. sativa. Further, transcriptomic analysis revealed the key genes associated with seed oil biosynthesis and its transcriptional regulation, including SAD, FAD2, FAD3, FAE1, ABI3, WRI1 and FUS3 displaying high expression levels in C. neglecta seeds. The high representability of C. neglecta as a model species for Camelina-based biotechnology research has been demonstrated for the first time. In particular, floral Agrobacterium tumefaciens infiltration-based transformation of C. neglecta, leading to overexpression of CvLPAT2, CpDGAT1 and CvFatB1 transgenes, was demonstrated for medium-chain fatty acid accumulation in C. neglecta seed oil. This study provides an important genomic resource and establishes C. neglecta as a new model for oilseed biotechnology research.

Reactive oxygen species (ROS) play a key role in a variety of biological processes, such as the perception of abiotic stress, the integration of different environmental signals, and the activation of stress response networks. Salt stress could induce an increased ROS accumulation in plants, disrupting intracellular redox homeostasis, leading to post-translational modifications (PTMs) of specific proteins, and eventually causing adaptive changes in metabolism. Here, we performed an iodoTMT-based proteomic approach to identify the sulfenylated proteins in B. napus root responsing to salt stress. Totally, 1 348 sulfenylated sites in 751 proteins were identified and these proteins were widely existed in different cell compartments and processes. Our study revealed that proteins with changed abundance and sulfenylation level in B. napus root under salt stress were mainly enriched in the biological processes of ion binding, glycolysis, ATP binding, and oxidative stress response. This study displays a landscape of sulfenylated proteins response to salt stress in B. napus root and provides some theoretical support for further understanding of the molecular mechanisms of redox regulation under salt stress in plants.

Abstract Background Brassica napus is an important oilseed crop providing high-quality vegetable oils for human consumption and non-food applications. However, the regulation between embryo and seed coat for the synthesis of oil and phenylpropanoid compounds remains largely unclear. Results Here, we analyzed the transcriptomes in developing seeds at 2-day intervals from 14 days after flowering (DAF) to 64 DAF. The 26 high-resolution time-course transcriptomes are clearly clustered into five distinct groups from stage I to stage V. A total of 2217 genes including 136 transcription factors, are specifically expressed in the seed and show high temporal specificity by being expressed only at certain stages of seed development. Furthermore, we analyzed the co-expression networks during seed development, which mainly included master regulatory transcription factors, lipid, and phenylpropane metabolism genes. The results show that the phenylpropane pathway is prominent during seed development, and the key enzymes in the phenylpropane metabolic pathway, including TT5, BAN, and the transporter TT19, were directly or indirectly related to many key enzymes and transcription factors involved in oil accumulation. We identified candidate genes that may regulate seed oil content based on the co-expression network analysis combined with correlation analysis of the gene expression with seed oil content and seed coat content. Conclusions Overall, these results reveal the transcriptional regulation between lipid and phenylpropane accumulation during B. napus seed development. The established co-expression networks and predicted key factors provide important resources for future studies to reveal the genetic control of oil accumulation in B. napus seeds.

Abstract Background Studies have indicated that long non-coding RNAs (lncRNAs) play important regulatory roles in many biological processes. However, the regulation of seed oil biosynthesis by lncRNAs remains largely unknown. Results We comprehensively identified and characterized the lncRNAs from seeds in three developing stages in two accessions of Brassica napus (B. napus), ZS11 (high oil content) and WH5557 (low oil content). Finally, 8094 expressed lncRNAs were identified. LncRNAs MSTRG.22563 and MSTRG.86004 were predicted to be related to seed oil accumulation. Experimental results show that the seed oil content is decreased by 3.1–3.9% in MSTRG.22563 overexpression plants, while increased about 2% in MSTRG.86004, compared to WT. Further study showed that most genes related to lipid metabolism had much lower expression, and the content of some metabolites in the processes of respiration and TCA (tricarboxylic acid) cycle was reduced in MSTRG.22563 transgenic seeds. The expression of genes involved in fatty acid synthesis and seed embryonic development (e.g., LEC1) was increased, but genes related to TAG assembly was decreased in MSTRG.86004 transgenic seeds. Conclusion Our results suggest that MSTRG.22563 might impact seed oil content by affecting the respiration and TCA cycle, while MSTRG.86004 plays a role in prolonging the seed developmental time to increase seed oil accumulation.

Abstract The Yinggehai Basin (YB) in the northwest of the South China Sea (SCS) has preserved the complete evolution of the Red River Fault (RRF), whose motion over time has largely contributed to shaping the current tectonic framework of the southeastern Tibetan Plateau and Indochina Block. Here we, for the first time, image the RRF, crustal architecture, and crust‐mantle boundary (i.e., Moho) in detail under the YB from two high‐resolution 40‐km‐depth seismic reflection pre‐stack migration profiles. Our seismic reflection images provide direct seismic evidence to support a deep‐penetrating RRF, most likely crosscutting the Moho. In this sense, the RRF was a large‐scale shear zone, along with the clockwise rotation of the Indochina Block, to accommodate the Indochina Block extrusion during Oligocene‐early Miocene and form the YB. We highlight that the material extrusion along deep‐penetrating faults dominated the Tibetan Plateau deformation in response to the India‐Asia collision at an early stage.

The Tamu Massif, considered the biggest single volcano on Earth, was formed by the accumulation of enormous amounts of magma erupting to the surface. It is the largest and oldest seamount in Shatsky Rise, which is the third largest oceanic plateau on Earth. However, the formation mechanism of Tamu Massif is still controversial because evidence point to different formation hypotheses. In this paper, we applied the P-wave coda autocorrelation method and used the hydrophone waveform data acquired by the ocean bottom seismometer (OBS) deployed on Tamu Massif to constrain the oceanic crust, and these results provide new finding on the structure of the oceanic crust for Tamu Massif. We hope it can provide some implications to research the formation mechanism of Tamu Massif. These results show that some stations in Tamu Massif received reflection signals from shallower depths that are nearly parallel to the seafloor. We infer that in the shallow oceanic crust, there is a layer composed of alternating eruptions of dense, higher velocity massive lava and sparse, lower velocity pillow lava flows, which have less density and lower velocity compared to the lower oceanic crust, with a strong acoustic impedance contrasts between them and thus able to generate a reflection signal, which is observed in our autocorrelation results.

Abstract Background Regulation of gene expression plays an essential role in controlling the phenotypes of plants. Brassica napus (B. napus) is an important source for the vegetable oil in the world, and the seed oil content is an important trait of B. napus. Results We perform a comprehensive analysis of the transcriptional variability in the seeds of B. napus at two developmental stages, 20 and 40 days after flowering (DAF). We detect 53,759 and 53,550 independent expression quantitative trait loci (eQTLs) for 79,605 and 76,713 expressed genes at 20 and 40 DAF, respectively. Among them, the local eQTLs are mapped to the adjacent genes more frequently. The adjacent gene pairs are regulated by local eQTLs with the same open chromatin state and show a stronger mode of expression piggybacking. Inter-subgenomic analysis indicates that there is a feedback regulation for the homoeologous gene pairs to maintain partial expression dosage. We also identify 141 eQTL hotspots and find that hotspot87-88 co-localizes with a QTL for the seed oil content. To further resolve the regulatory network of this eQTL hotspot, we construct the XGBoost model using 856 RNA-seq datasets and the Basenji model using 59 ATAC-seq datasets. Using these two models, we predict the mechanisms affecting the seed oil content regulated by hotspot87-88 and experimentally validate that the transcription factors, NAC13 and SCL31, positively regulate the seed oil content. Conclusions We comprehensively characterize the gene regulatory features in the seeds of B. napus and reveal the gene networks regulating the seed oil content of B. napus.

Imaging of multiples, as a supplement to imaging of primaries, can provide a wider range of subsurface illumination. Therefore, it can provide more detailed information on subsurface structures. However, imaging of multiples suffers from crosstalk issues generated by unrelated events. Many strategies have been proposed to attenuate crosstalk, among which the angle domain Radon crosstalk attenuation algorithm achieves good application effect. In the angle domain, the true imaging is flat, while the crosstalk events have moveouts. Therefore, it is convenient to identify the crosstalk in angle gathers using the Radon transform. However, the conventional Radon transform lacks a quantitative description for crosstalk in angle gathers, which would affect the accuracy of crosstalk attenuation. In this paper, residual moveout kernels are derived with a Radon transform to attenuate crosstalk in angle gathers for imaging of multiples. First, two types of residual moveout (RMO) equations are derived based on the causality of crosstalk. A three-layer model is used to verify the correctness of the analytical solutions. Then, based on the derived equations, the two types of crosstalk can be attenuated respectively in the Radon domain. Synthetic experiments demonstrate that the derived RMO equations can effectively attenuate the crosstalk events in imaging of multiples.

Due to high spatial resolution, low cost, and wide bandwidth, distributed optical fiber acoustic sensing (DAS) is regarded as a potential tool for data acquisition in vertical seismic profile (VSP) surveys. However, in real DAS-VSP records, desired signals are often seriously plagued by various noise, which does not appear in the conventional seismic data received by electronic geophones. Exploring a high-performing attenuation method for the background noise can significantly improve the quality of DAS-VSP records and has essential impacts on the following imaging and interpretation. Deep-learning-based methods, especially convolutional neural network (CNN), have shown remarkable performance in seismic data denoising. However, the conventional CNN-based methods may degrade when dealing with DAS-VSP records in low signal-to-noise ratio. In this study, we propose a novel multi-scale dense-connection denoising network (MDD-Net) to achieve high-accuracy processing of the complex DAS background noise. Unlike conventional multi-scale networks, MDD-Net utilizes widen convolution block to capture the multi-scale features of the analyzed data. On this basis, dense connection operations are employed to fuse the features and improve the network efficiency. Meanwhile, an enhanced spatial attention (ESA) block is designed to reinforce the features, which are helpful for noise suppression and weak signal recovery. Both synthetic and field DAS-VSP records are processed to verify the effectiveness of MDD-Net. Meanwhile, we also compare the denoising results with other competing methods. The experimental results demonstrate that MDD-Net can significantly attenuate the complex DAS background noise and restore the desired signals, even for the weak upgoing signals.

Flowering time is strongly related to the environment, while the genotype-by-environment interaction study for flowering time is lacking in Brassica napus. Here, a total of 11,700,689 single nucleotide polymorphisms in 490 B. napus accessions were used to associate with the flowering time and related climatic index in eight environments using a compressed variance-component mixed model, 3VmrMLM. As a result, 19 stable main-effect quantitative trait nucleotides (QTNs) and 32 QTN-by-environment interactions (QEIs) for flowering time were detected. Four windows of daily average temperature and precipitation were found to be climatic factors highly correlated with flowering time. Ten main-effect QTNs were found to be associated with these flowering-time-related climatic indexes. Using differentially expressed gene (DEG) analysis in semi-winter and spring oilseed rapes, 5,850 and 5,511 DEGs were found to be significantly expressed before and after vernalization. Twelve and 14 DEGs, including 7 and 9 known homologs in Arabidopsis, were found to be candidate genes for stable QTNs and QEIs for flowering time, respectively. Five DEGs were found to be candidate genes for main-effect QTNs for flowering-time-related climatic index. These candidate genes, such as BnaFLCs, BnaFTs, BnaA02.VIN3, and BnaC09.PRR7, were further validated by the haplotype, selective sweep, and co-expression networks analysis. The candidate genes identified in this study will be helpful to breed B. napus varieties adapted to particular environments with optimized flowering time.

Redox regulation plays a wide role in plant growth, development, and adaptation to stresses. Sulfenylation is one of the reversible oxidative post-transcriptional modifications. Here we performed an iodoTMT-based proteomic analysis to identify the redox sensitive proteins in vivo under freezing stress after cold acclimation in Brassica napus. Totally, we obtained 1,372 sulfenylated sites in 714 proteins. The overall sulfenylation level displayed an increased trend under freezing stress after cold acclimation. We identified 171 differentially sulfenylated proteins (DSPs) under freezing stress, which were predicted to be mainly localized in chloroplast and cytoplasm. The up-regulated DSPs were mainly enriched in photosynthesis and glycolytic processes and function of catalytic activity. Enzymes involved in various pathways such as glycolysis and Calvin-Benson-Bassham (CBB) cycle were generally sulfenylated and the metabolite levels in these pathways was significantly reduced under freezing stress after cold acclimation. Furthermore, enzyme activity assay confirmed that the activity of cytosolic pyruvate kinase and malate dehydrogenase 2 was significantly reduced under H2O2 treatment. Our study provides a landscape of redox sensitive proteins in B. napus in response to freezing stress after cold acclimation, which proposes a basis for understanding the redox regulation in plant metabolic response to freezing stress after cold acclimation.

Plants produce and accumulate triacylglycerol (TAG) in their seeds as an energy reservoir to support the processes of seed germination and seedling development. Plant seed oils are vital not only for the human diet but also as renewable feedstocks for industrial use. TAG biosynthesis consists of two major steps: de novo fatty acid biosynthesis in the plastids and TAG assembly in the endoplasmic reticulum. The latest advances in unraveling transcriptional regulation have shed light on the molecular mechanisms of plant oil biosynthesis. We summarize recent progress in understanding the regulatory mechanisms of well-characterized and newly discovered transcription factors and other types of regulators that control plant fatty acid biosynthesis. The emerging picture shows that plant oil biosynthesis responds to developmental and environmental cues that stimulate a network of interacting transcriptional activators and repressors, which in turn fine-tune the spatiotemporal regulation of the pathway genes.

Most plants are sensitive to salt-alkali stress, and the degree of tolerance to salt-alkali stress varies from different species and varieties. In order to explore the salt-alkali stress adaptability of Brassica napus, we collected the phenotypic data of 505 B. napus accessions at seedling and mature stages under control, low and high salt-alkali soil stress conditions in Inner Mongolia of China. Six resistant and 5 sensitive materials, respectively, have been identified both in Inner Mongolia and Xinjiang Uygur Autonomous Region of China. Genome-wide association studies (GWAS) for 15 absolute values and 10 tolerance coefficients (TCs) of growth and agronomic traits were applied to investigate the genetic basis of salt-alkali tolerance of B. napus. We finally mapped 9 significant QTLs related to salt-alkali stress response and predicted 20 candidate genes related to salt-alkali stress tolerance. Some important candidate genes, including BnABA4, BnBBX14, BnVTI12, BnPYL8, and BnCRR1, were identified by combining sequence variation annotation and expression differences. The identified valuable loci and germplasms could be useful for breeding salt-alkali-tolerant B.napus varieties. This study laid a foundation for understanding molecular mechanism of salt-alkali stress adaptation and provides rich genetic resources for the large-scale production of B. napus on salt-alkali land in the future.

Rapeseed (Brassica napus) is an important oilseed crop widely planted in the world, providing substantial edible oil and other nutrients for mankind. The composition of fatty acids affects the edible and processing quality of vegetable oils, among which erucic acid (EA) is potentially to cause health problems. Therefore, low erucic acid (LEA) has always been a breeding trait of B. napus. Fatty acid elongase 1 (FAE1) plays a decisive role in the synthesis of EA. There are two functional homologous copies of FAE1 on the A08 and C03 chromosomes in B. napus. In this study, we used CRISPR/Cas9 technology to create targeted mutations on these two homologous copies of BnaFAE1 in three B. napus germplasms with high EA (>30%) and high oil (>50%). Our results show that the EA content was significantly reduced by more than 10 percentage points in the mutant of BnaC03.FAE1 (c03), while the double mutation of BnaA08.FAE1 and BnaC03.FAE1 (a08c03) resulted in nearly zero EA in three BnaFAE1-edited germplasms, and the oleic acid content was increased in different degrees. In addition, knockout of BnaA08.FAE1 or/and BnaC03.FAE1 mildly decreased seed oil content, but had no significant effect on other agronomic traits. In general, we successfully created low EA germplasms of B. napus, which provides a feasible way for future low EA breeding.

Hyperhomocysteinemia induces stress response in endoplasmic reticulum (ERS). Here, we tested whether blockage of homocysteine (Hcy) induced ERS and subsequent apoptosis in vascular smooth muscle cells can be inhibited by blockage of PERK/eIF2α/ATF4/CHOP signaling. Short-term exposure of vascular smooth muscle cells to Hcy led to the phosphorylation of PERK (pPERK), which in turn, phosphorylated eIF2 alpha (peIF2α) and inhibited the unfolded protein response. Long-term Hcy exposure, however, increased the expression of ATF-4 and CHOP and led to apoptosis. Treatment of cells with salubrinal, a specific inhibitor for eIF2α decreased the expression of ATF-4 and CHOP, and prevented apoptosis. Together, the results show that PERK pathway is involved in Hcy-induced vascular smooth muscle cell apoptosis and that blocking the PERK pathway protects against this injury.

Most crops are sensitive to salt stress, but their degree of susceptibility varies among species and cultivars. In order to understand the salt stress adaptability of Brassica napus to salt stress, we collected the phenotypic data of 505 B. napus accessions at the germination stage under 150 or 215 mM sodium chloride (NaCl) and at the seedling stage under 215 mM NaCl. Genome-wide association studies (GWAS) of 16 salt tolerance coefficients (STCs) were applied to investigate the genetic basis of salt stress tolerance of B. napus. In this study, we mapped 31 salts stress-related QTLs and identified 177 and 228 candidate genes related to salt stress tolerance were detected at germination and seedling stages, respectively. Overexpression of two candidate genes, BnCKX5 and BnERF3 overexpression, were found to increase the sensitivity to salt and mannitol stresses at the germination stage. This study demonstrated that it is a feasible method to dissect the genetic basis of salt stress tolerance at germination and seedling stages in B. napus by GWAS, which provides valuable loci for improving the salt stress tolerance of B. napus. Moreover, these candidate genes are rich genetic resources for the following exploration of molecular mechanisms in adaptation to salt stress in B. napus.

Natural protein-based hydrogels possess excellent biocompatibility; however, most of them are weak or brittle. In the present work, high strength hybrid dual-crosslinking BSA gels (BSA DC gels), which have both chemical cross-linking and physical cross-linking, were fabricated by a facile photoreaction-heating process. BSA DC gels showed high transparency (light transmittance of ~90%) and high strength. At optimal conditions, BSA DC gel exhibited high compressive strength (σc,f) of 37.81 ± 2.61 MPa and tensile strength (σt,f) of 0.62 ± 0.078 MPa, showing it to be much stronger than physically cross-linked BSA gel (BSA PC gel) and chemically cross-linked BSA gel (BSA CC gel). More importantly, BSA DC gel displayed non-swelling properties while maintaining high strength in DI water, pH = 3.0, and pH = 10.0. Moreover, BSA DC gel also demonstrated large hysteresis, rapid self-recovery, and excellent fatigue resistance properties. It is believed that our BSA DC gel can potentially be applied in biomedical fields.

Brassica napus (B. napus) is the world's most widely grown temperate oilseed crop. Although breeding for human consumption has led to removal of erucic acid from refined canola oils, there is renewed interest in the industrial uses of erucic acid derived from B. napus, and there is a rich germplasm available for use. Here, low- and high-erucic acid accessions of B. napus seeds were examined for the distribution of erucic acid-containing lipids and the gene transcripts encoding the enzymes involved in pathways for its incorporation into triacylglycerols (TAGs) across the major tissues of the seeds. In general, the results indicate that a heterogeneous distribution of erucic acid across B. napus seed tissues was contributed by two isoforms (out of six) of FATTY ACYL COA ELONGASE (FAE1) and a combination of phospholipid:diacylglycerol acyltransferase (PDAT)- and diacylglycerol acyltransferase (DGAT)-mediated incorporation of erucic acid into TAGs in cotyledonary tissues. An absence of the expression of these two FAE1 isoforms accounted for the absence of erucic acid in the TAGs of the low-erucic accession.

Abstract In past two decades, numerous lipidomics approaches based on mass spectrometry with or without liquid chromatography separation have been established for identification and quantification of lipids in plants. In this study, we developed an efficient and comprehensive lipidomics approach based on UPLC with an Acquity UPLCTM BEH C18 column coupled to TripleTOF using ESI in positive ion mode and MS/MSALL scan for data collection. Lipid extract was prepared to 2 mg/ml solution according to dry tissue weight and mixed with 13 kinds of internal standards including PA, PC, PE, and PG. Each analysis required single injection of 5–10 μl lipid solvent and completed in 32 min. A target method dataset was generated using the LipidView software for prediction of the accurate mass of target lipid species. The dataset was uploaded into the PeakView to create processing datasets to search target lipid species, which achieved batch data processing of multiple samples for lipid species‐specific identification and quantification. As proof of concept, we profiled the lipids of different tissues of rapeseed. Thirteen lipid classes including 218 glycerolipids were identified including 46 TAGs, 15 DAGs, 20 PCs, 24 PEs, 13 PGs, 14 PIs, 26 PSs, 12 PAs, 16 MGDGs, 16 DGDGs, 6 LysoPCs, 5 LysoPEs, and 5 LysoPGs. Together, our approach permits the analysis of glycerolipids in plant tissues with simplicity in sample analysis and data processing using UPLC‐TripleTOF.

The present study was designed to evaluate the effect of quercetin on myocardial oxidative stress and immunity function impairment induced by isoproterenol in rats. To induce myocardial ischemia, Wistar rats were subcutaneously injected with isoproterenol (70 mg/kg). Blood immunity index, cardiac marker enzymes and antioxidative parameters in hearts were measured. It was found that the levels of blood AST, creatine kinase, NO, NOS, IL-10, IL-1, IL-8 and lactate dehydrogenase in isoproterenol-treated rats were significantly increased. The rats administrated with isoproterenol showed the declines in myocardial antioxidant enzymes activities. Administration of quercetin significantly ameliorated myocardial oxidative injury and immunity function impairment induced by isoproterenol. The results indicated that quercetin possesses activity against isoproterenol-induced myocardial oxidative injury and immunity function impairment, and that the mechanism of pharmacological action was related at least in part to the antioxidant activity of quercetin.

The aim of the study was to investigate the effect of Ginkgo biloba extract 50 (GBE50), a well-known natural antioxidant, against immunity and antioxidant enzyme activities in ischemia reperfusion (IR) rats. Rats were then divided into six groups fed for 15 days with the same diet: three groups (IV, V, VI) were treated by different doses of GBE50 suspension [20, 40, or 60 mg/kg body weight by oral gavage every day at a fixed time (10.00 a.m.)] (equal to 5, 10 and 20 times, respectively, the maximum recommended human dose), and three groups (I, II, III) were untreated. At the end of the experiment, rats’ hearts were subjected to 30 min of ischemia followed by 90 min of reperfusion. Results showed that IR significantly enhanced heart rate, S-T height, myocardium (myeloperoxidase) MPO activity and blood interleukin-8 (IL-8), tumor necrosis factor Alpha (TNF-a), interleukin-1β (IL-1β) levels, blood aspartate transaminase (AST), lactate dehydrogenase (LDH), and creatinine kinase (CK) activities, reduced myocardium sodium-potassium adenosine triphosphatase (Na+-K+-ATPase), calcium-magnesium adenosine triphosphatase (Ca2+-Mg2+-ATPase) activities and antioxidant enzyme activities in IR group (III) compared to sham control group (II). Pretreatment of GBE50 markedly significantly reduced heart rate, S-T height, myocardium MPO activity and blood IL-8, TNF-a, IL-1β levels, blood AST, LDH, and CK activities, enhanced myocardium Na+-K+-ATPase, Ca2+-Mg2+-ATPase activities and antioxidant enzyme activities in IR group (II) compared to IR group (III). The results suggested that the GBE50 may reduce the oxidative stress in the reperfused myocardium, and increased immunity and antioxidant activities in IR rats.