Systematic characterization of CsbZIP transcription factors in Camelina sativa and functional analysis of CsbZIP-A12 mediating regulation of unsaturated fatty acid-enriched oil biosynthesis.

The basic leucine zipper (bZIP) transcription factors (TFs) function importantly in numerous life processes in plants. However, bZIP members and their biological roles remain unknown in Camelina sativa, a worldwide promising oil crop. Here, 220 CsbZIP proteins were identified in camelina and classified into thirteen groups. Two and 347 pairs of tandem and segmental duplication genes were detected to be underwent purification selection, with segmental duplication as the main driven-force of CsbZIP gene family expansion. Most CsbZIP genes displayed a tissue-specific expression pattern. Particularly, CsbZIP-A12 significantly positively correlated with many FA/oil biosynthesis-related genes, indicating CsbZIP-A12 may regulate lipid biosynthesis. Notably, yeast one-hybrid (Y1H), ß-Glucuronidase (GUS), dual-luciferase (LUC) and EMSA assays evidenced that CsbZIP-A12 located in nucleus interacted with the promoters of CsSAD2-3 and CsFAD3-3 genes responsible for unsaturated fatty acid (UFA) synthesis, thus activating their transcriptions. Overexpression of CsbZIP-A12 led to an increase of total lipid by 3.275 % compared to the control, followed with oleic and α-linolenic acid levels enhanced by 3.4 % and 5.195 %, and up-regulated the expressions of CsSAD2-3, CsFAD3-3 and CsPDAT2-3 in camelina seeds. Furthermore, heterogeneous expression of CsbZIP-A12 significantly up-regulated the expressions of NtSAD2, NtFAD3 and NtPDAT genes in tobacco plants, thereby improving the levels of total lipids and UFAs in both leaves and seeds without negative effects on other agronomic traits. Together, our findings suggest that CsbZIP-A12 upregulates FA/oil biosynthesis by activating CsSAD2-3 and CsFAD3-3 as well as possible other related genes. These data lay a foundation for further functional analyses of CsbZIPs, providing new insights into the TF-based lipid metabolic engineering to increase vegetable oil yield and health-beneficial quality in oilseeds.

Effect of the combined binding of topotecan and catechin/protocatechuic acid to a pH-sensitive DNA tetrahedron on release and cytotoxicity: Spectroscopic and calorimetric studies.

The therapeutic efficacy of chemotherapy drugs can be effectively improved through the dual effects of their combination with natural polyphenols and the delivery of targeted DNA nanostructures. In this work, the interactions of topotecan (TPT), (+)-catechin (CAT), or protocatechuic acid (PCA) with a pH-sensitive DNA tetrahedron (MUC1-TD) in the binary and ternary systems at pHs 5.0 and 7.4 were investigated by fluorescence spectroscopy and calorimetry. The intercalative binding mode of TPT/CAT/PC to MUC1-TD was confirmed, and their affinity was ranked in the order of PCA > CAT > TPT. The effects of the pH-sensitivity of MUC1-TD and different molecular structures of CAT and PCA on the loading, release, and cytotoxicity of TPT were discussed. The weakened interaction under acidic conditions and the co-loading of CAT/PCA, especially PCA, improved the release of TPT loaded by MUC1-TD. The targeting of MUC1-TD and the synergistic effect with CAT/PCA, especially CAT, enhanced the cytotoxicity of TPT on A549 cells. For L02 cells, the protective effect of CAT/PCA reduced the damage caused by TPT. The single or combined TPT loaded by MUC1-TD was mainly concentrated in the nucleus of A549 cells. This work will provide key information for the combined application of TPT and CAT/PCA loaded by DNA nanostructures to improve chemotherapy efficacy and reduce side effects.

Multi-spectroscopic and molecular docking studies for the pH-dependent interaction of ß-lactoglobulin with (-)-epicatechin gallate and/or piceatannol: Influence on antioxidant activity and stability.

(-)-Epicatechin gallate (ECG) and piceatannol (PIC) are commonly polyphenols with excellent biological activities. ß-Lactoglobulin (BLG) is a food-grade globule protein and its morphologies are sensitive to pH. This study used experimental and computational methods to determine the interaction of single or combined ECG and PIC with BLG at different pHs. The static quenching process was determined through fluorescence and ultraviolet-visible spectroscopy. Compared with ECG, PIC could significantly bind to BLG with higher affinity. Their binding affinity for BLG with different morphologies followed the tendency of monomer > dimer > tetramer. The negative contribution of van der Waals forces, electrostatic interactions, and hydrogen bonds to ΔHo exceeded the positive contribution of hydrophobic interactions in the spontaneous and exothermic process. The reduced binding affinity in the ternary systems demonstrated the competitive binding between ECG and PIC on BLG, and the hinder effect of ECG or PIC was enhanced with increasing pH. Molecular docking studies revealed the same binding sites of ECG and PIC on various conformations of BLG and identical driven forces as thermodynamic results. Tryptophan and tyrosine were the main participators in the BLG + ECG and BLG + PIC systems, respectively. The conformational changes in the binary and ternary systems could be ascertained through synchronous fluorescence, circular dichroism, and dynamic light scattering. Furthermore, the effects of pH and BLG encapsulation on the antioxidant capacity and stability of ECG or PIC were also implemented. ECG or PIC was the most stable in the (BLG + PIC) + ECG system at pH 6.0. This study could clarify the interaction mechanism between ECG/PIC and BLG and elucidate the pH effect on their binding information. The results will provide basic support for their usage in food processing and applications.

Mechanistic engineering of celastrol liposomes induces ferroptosis and apoptosis by directly targeting VDAC2 in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is one of most common and deadliest malignancies. Celastrol (Cel), a natural product derived from the Tripterygium wilfordii plant, has been extensively researched for its potential effectiveness in fighting cancer. However, its clinical application has been hindered by the unclear mechanism of action. Here, we used chemical proteomics to identify the direct targets of Cel and enhanced its targetability and anti-tumor capacity by developing a Cel-based liposomes in HCC. We demonstrated that Cel selectively targets the voltage-dependent anion channel 2 (VDAC2). Cel directly binds to the cysteine residues of VDAC2, and induces cytochrome C release via dysregulating VDAC2-mediated mitochondrial permeability transition pore (mPTP) function. We further found that Cel induces ROS-mediated ferroptosis and apoptosis in HCC cells. Moreover, coencapsulation of Cel into alkyl glucoside-modified liposomes (AGCL) improved its antitumor efficacy and minimized its side effects. AGCL has been shown to effectively suppress the proliferation of tumor cells. In a xenograft nude mice experiment, AGCL significantly inhibited tumor growth and promoted apoptosis. Our findings reveal that Cel directly targets VDAC2 to induce mitochondria-dependent cell death, while the Cel liposomes enhance its targetability and reduces side effects. Overall, Cel shows promise as a therapeutic agent for HCC.

Effects of combined binding of chlorogenic acid/caffeic acid and gallic acid to trypsin on their synergistic antioxidant activity, enzyme activity and stability.

The combined application of multiple natural polyphenols in functional foods may provide better health benefits. The binding of polyphenols with different structures to proteins will affect their respective functions. Spectroscopy and molecular docking were used to investigate the competitive binding of chlorogenic acid (CGA)/caffeic acid (CA) and gallic acid (GA) to trypsin. The effects of different molecular structures and the order of adding the three phenolic acids on the binding were assessed. The stability of trypsin and its docked complexes with CGA/CA/GA was evaluated by molecular dynamics simulation. The effects of the binding process on the activity and thermal stability of trypsin, as well as on the antioxidant activity and stability of CGA/CA/GA were explored. The competitive binding of CGA/CA and GA to trypsin affected their synergistic antioxidant effects. The results may provide a reference for the combined application of CGA/CA and GA in food and pharmaceutical fields.

Spectroscopic, calorimetric and cytotoxicity studies on the combined binding of daunorubicin and acridine orange to a DNA tetrahedron.

Chemotherapy-phototherapy (CTPT) combination drugs co-loaded by targeted DNA nanostructures can achieve controlled drug delivery, reduce toxic side effects and overcome multidrug resistance. Herein, we constructed and characterized a DNA tetrahedral nanostructure (MUC1-TD) linked with the targeting aptamer MUC1. The interaction of daunorubicin (DAU)/acridine orange (AO) alone and in combination with MUC1-TD and the influence of the interaction on the cytotoxicity of the drugs were evaluated. Potassium ferrocyanide quenching analysis and DNA melting temperature assays were used to demonstrate the intercalative binding of DAU/AO to MUC1-TD. The interactions of DAU and/or AO with MUC1-TD were analyzed by fluorescence spectroscopy and differential scanning calorimetry. The number of binding sites, binding constant, entropy and enthalpy changes of the binding process were obtained. The binding strength and binding sites of DAU were higher than those of AO. The presence of AO in the ternary system weakened the binding of DAU to MUC1-TD. In vitro cytotoxicity studies demonstrated that the loading of MUC1-TD augmented the inhibitory effects of DAU and AO and the synergistic cytotoxic effects of DAU + AO on MCF-7 cells and MCF-7/ADR cells. Cell uptake studies showed that the loading of MUC1-TD was beneficial in promoting the apoptosis of MCF-7/ADR cells due to its enhanced targeting to the nucleus. This study has important guiding significance for the combined application of DAU and AO co-loaded by DNA nanostructures to overcome multidrug resistance.

Multifunctional Nanoplatform for Mild Microwave-Enhanced Thermal, Antioxidative, and Chemotherapeutic Treatment of Rheumatoid Arthritis.

Rheumatoid arthritis (RA) is usually associated with excessive proliferation of M1-type proinflammatory macrophages, resulting in severe hypoxia and excess reactive oxygen species (ROS) in the joint cavity. Inhibiting M1-type proinflammatory macrophages and/or repolarizing them into M2 phenotype anti-inflammatory cells by alleviating hypoxia and scavenging ROS could be a promising strategy for RA treatment. In this work, a microwave-sensitive metal-organic framework of UiO-66-NH2 is constructed for coating a nanoenzyme of cerium oxide (CeO2) and loading with the drug celastrol (Cel) to give UiO-66-NH2/CeO2/Cel, which is ultimately wrapped with hyaluronic acid (HA) to form a nanocomposite UiO-66-NH2/CeO2/Cel@HA (UCCH). With the microwave-susceptible properties of UiO-66-NH2, the thermal effect of microwaves can eliminate the excessive proliferation of inflammatory cells. In addition, superoxide-like and catalase-like activities originating from CeO2 in UCCH are boosted to scavenge ROS and accelerate the decomposition of H2O2 to produce O2 under microwave irradiation. The nonthermal effect of microwaves could synergistically promote the repolarization of M1-type macrophages into the M2 phenotype. Accompanied by the release of the anti-RA chemotherapeutic drug Cel, UCCH can efficiently ameliorate RA in vitro and in vivo through microwave-enhanced multisynergistic effects. This strategy could inspire the design of other multisynergistic platforms enhanced by microwaves to exploit new treatment modalities in RA therapies.

Triphenyl phosphate (TPP) promotes hepatocyte toxicity via induction of endoplasmic reticulum stress and inhibition of autophagy flux.

Triphenyl phosphate (TPP), a commonly used organophosphate flame retardant, is frequently found in environmental and biota samples, indicating widespread human exposure. Recent studies have shown that TPP causes hepatotoxicity, but the underlying cellular mechanisms are not fully elucidated. Here, by using normal hepatocyte AML12 cells as a model, we showed that TPP induced apoptotic cell death. RNA sequencing analyses revealed that differentially expressed genes induced by TPP were related to endoplasmic reticulum (ER) stress and autophagy. Immunostaining and western blot results further confirmed that TPP activated ER stress. Interestingly, though TPP increased LC3-II, a canonical marker for autophagy, TPP inhibited autophagy flux rather than induced autophagy. Interestingly, TPP-induced ER stress facilitated autophagy flux inhibition and apoptosis. Furthermore, inhibition of autophagy aggravated, and activation of autophagy attenuated apoptosis induced by TPP. Collectively, these results uncovered that ER stress and autophagy flux inhibition were responsible for TPP-induced apoptosis in mouse hepatocytes. Thus, our foundlings provided novel insight into the potential mechanisms of TPP-induced hepatocyte toxicity.

Blood-Enriching Effects and Immune-Regulation Mechanism of Steam-Processed Polygonatum Sibiricum Polysaccharide in Blood Deficiency Syndrome Mice.

Polygonatum sibiricum Red. has been used as a medicinal herb and nutritional food in traditional Chinese medicine for a long time. It must be processed prior to clinical use for safe and effective applications. However, the present studies mainly focused on crude Polygonatum sibiricum (PS). This study aimed to investigate the chemical properties, blood-enriching effects and mechanism of polysaccharide from the steam-processed Polygonatum sibiricum (SPS), which is a common form of PS in clinical applications. Instrumentation analyses and chemistry analyses revealed the structure of SPS polysaccharide (SPSP). A mice model of blood deficiency syndrome (BDS) was induced by acetylphenylhydrazine (APH) and cyclophosphamide (CTX). Blood routine test, spleen histopathological changes, serum cytokines, etc. were measured. The spleen transcriptome changes of BDS mice were detected by RNA sequencing (RNA-seq). The results showed that SPSP consists predominantly of Gal and GalA together with fewer amounts of Man, Glc, Ara, Rha and GlcN. It could significantly increase peripheral blood cells, restore the splenic trabecular structure, and reverse hematopoietic cytokines to normal levels. RNA-seq analysis showed that 122 differentially expressed genes (DEGs) were obtained after SPSP treatment. GO and KEGG analysis revealed that SPSP-regulated DEGs were mainly involved in hematopoiesis, immune regulation signaling pathways. The reliability of transcriptome profiling was validated by quantitative real-time PCR and Western blot, and the results indicated that the potential molecular mechanisms of the blood-enriching effects of SPSP might be associated with the regulating of JAK1-STAT1 pathway, and elevated the hematopoietic cytokines (EPO, G-CSF, TNF-α and IL-6). This work provides important information on the potential mechanisms of SPSP against BDS.

Stable Room-Temperature Sodium-Sulfur Batteries in Ether-Based Electrolytes Enabled by the Fluoroethylene Carbonate Additive.

Because of its high energy density and low cost, the room-temperature sodium-sulfur (RT Na-S) battery is a promising candidate to power the next-generation large-scale energy storage system. However, its practical utilization is hampered by the short life span owing to the severe shuttle effect, which originates from the "solid-liquid-solid" reaction mechanism of the sulfur cathode. In this work, fluoroethylene carbonate is proposed as an additive, and tetraethylene glycol dimethyl ether is used as the base solvent. For the sulfurized polyacrylonitrile cathode, a robust F-containing cathode-electrolyte interphase (CEI) forms on the cathode surface during the initial discharging. The CEI prohibits the dissolution and diffusion of the soluble intermediate products, realizing a "solid-solid" reaction process. The RT Na-S cell exhibits a stable cycling performance: a capacity of 587 mA h g-1 is retained after 200 cycles at 0.2 A g-1 with nearly 100% Coulombic efficiency.

Coix seed polysaccharides alleviate type 2 diabetes mellitus via gut microbiota-derived short-chain fatty acids activation of IGF1/PI3K/AKT signaling.

Type 2 diabetes mellitus (T2DM) has become a worldwide concern in recent years. Coix seed (CS) as a homologous substance of traditional Chinese medicine and food, its polysaccharides can improve the symptoms of patients with metabolic disorders. Since most plant polysaccharides are difficult to digest and absorb, we hypothesized that Coix seed polysaccharides (CSP) exert hypoglycemic effects through the gut. In this study, the underlying mechanisms regulating hypoglycemic effects of CSP on a T2DM mouse model were investigated. After treatment with CSP, serum insulin and high-density lipoprotein cholesterol levels were increased, while total cholesterol, triglycerides and low-density lipoprotein cholesterol levels were decreased in T2DM mice. In addition, CSP treatment helped repair the intestinal barrier and modulated the gut microbial composition in T2DM mice, mainly facilitating the growth of short-chain fatty acid (SCFA)-producing bacteria, Spearman's analysis revealed these bacteria were positively related with the hypoglycemic efficacy of CSP. Colonic transcriptome analysis indicated the hypoglycemic effect of CSP was associated with the activation of the IGF1/PI3K/AKT signaling pathway. Correlative analysis revealed that this activation may result from the increase of SCFAs-producing bacteria by CSP. GC-MS detection verified that CSP treatment increased fecal SCFAs levels. Molecular docking revealed that SCFAs could bind with IGF1, PI3K, and AKT. Our findings demonstrated that CSP treatment modulates gut microbial composition, especially of the SCFAs-producing bacteria, activates the IGF1/PI3K/AKT signaling pathways, and exhibits hypoglycemic efficacy.

Functional characterization of an novel acyl-CoA:diacylglycerol acyltransferase 3-3 (CsDGAT3-3) gene from Camelina sativa.

Diacylglycerol acyltransferases (DGAT) catalyze the final committed step of de novo biosynthesis of triacylglycerol (TAG) in plant seeds. This study was to functionally characterize DGAT3 genes in Camelina sativa, an important oil crops accumulating high levels of unsaturated fatty acids (UFAs) in seeds. Three camelina DGAT3 genes (CsDGAT3-1, CsDGAT3-2 and CsDGAT3-3) were identified, and the encoded proteins were predicted to be cytosolic-soluble proteins present as a homodimer containing the 2Fe-2S domain. They had divergent expression patterns in various tissues, suggesting that they may function in tissue-specific manner with CsDGAT3-1 in roots, CsDGAT3-2 in flowers and young seedlings, and CsDGAT3-3 in developing seeds. Functional complementation assay in yeast demonstrated that CsDGAT3-3 restored TAG synthesis. TAG content and UFAs, particularly eicosenoic acid (EA, 20:1n-9) were largely increased by adding exogenous UFAs in the yeast medium. Further heterogeneously transient expression in N. benthamiana leaves and seed-specific expression in tobacco seeds indicated that CsDGAT3-3 significantly enhanced oil and UFA accumulation with much higher level of EA. Overall, CsDGAT3-3 exhibited a strong abilty catalyzing TAG synthesis and high substrate preference for UFAs, especially for 20:1n-9. The present data provide new insights for further understanding oil biosynthesis mechanism in camelina seeds, indicating that CsDGAT3-3 may have practical applications for increasing both oil yield and quality.

[Preliminary study of dihydroartemisin in inhibiting invasion and metastasis of hepatoma cells].

It is reported that dihydroartemisinin could reduce the expression of phosphorylated adhesion kinase and matrix metalloproteinase-2, inhibit the growth, migration and invasion of ovarian cancer cells, promote the formation of Treg cells through TGF-beta/Smad signaling pathway, and play an immunosuppressive role; dihydroartemisinin could also inhibit the growth of lung cancer cells by inhibiting the expression of vascular endothelial growth factor(VEGF) receptor KDR. However, there are few studies on dihydroartemisinin in hepatocellular carcinoma cells. In order to preliminarily explore the effect of dihydroartemisinin on invasion and metastasis of hepatocellular carcinoma cells, CCK-8 method and crystal violet staining were used to detect the effect of dihydroartemisinin on the growth of hepatocellular carcinoma cell 7402 and highly metastatic hepatocellular carcinoma cell MHCC97 H. The effects of dihydroartemisinin on the invasion and metastasis of hepatocellular carcinoma cell 7402 and highly metastatic hepatocellular carcinoma cell MHCC97 H were studied by using cell wound healing and Transwell. Western blot was used to detect the protein expression of epidermal growth factor receptor(EGFR) and its downstream signaling pathway in cells treated with dihydroartemisinin for 48 hours. The results showed that dihydroartemisinin could inhibit the growth of hepatocellular carcinoma cell 7402 and highly metastatic hepatocellular carcinoma cell MHCC97 H at 25 µmol·L~(-1). As compared with the control group, the number of cell clones was significantly reduced, and the ability of cell migration and invasion was weakened. Western blot results showed that as compared with the control group, dihydroartemisinin group could down-regulate the protein expression of EGFR and its downstream signaling pathways p-AKT, p-ERK, N-cadherin, Snail and Slug, and up-regulate the expression of E-cadherin protein, thus affecting the migration, invasion and metastasis of hepatocellular carcinoma cells 7402 and MHCC97 H.

A cell line resistant to avian leukosis virus subgroup B infection.

The expression of env proteins that bind to viral cell receptors on avian leukosis virus (ALV)-susceptible cells can block ALV infection. In this study, we constructed a cell line (DF-1/B) by expressing the ALV-B env protein in DF-1 cells. PCR, immune fluorescence assay, Western blot, and immune electron microscopy results showed that the env gene can be stably expressed in DF-1cells and the env protein could be detected on the DF-1 cell membrane. An antiviral experiment concluded that the DF-1/B cell line could be resistant to 1 × 104 TCID50 ALV-B virus infection, but had no inhibitory effect on other subgroup ALV. This means that the DF-1/B cell line is specifically resistant to ALV-B and can be used as a tool for ALV-B diagnosis.

Ether-compatible sulfurized polyacrylonitrile cathode with excellent performance enabled by fast kinetics via selenium doping.

Sulfurized polyacrylonitrile is suggested to contain Sn (n ≤ 4) and shows good electrochemical performance in carbonate electrolytes for lithium sulfur batteries. However inferior results in ether electrolytes suggest that high solubility of Li2Sn (n ≤ 4) trumps the limited redox conversion, leading to dissolution and shuttling. Here, we introduce a small amount of selenium in sulfurized polyacrylonitrile to accelerate the redox conversion, delivering excellent performance in both carbonate and ether electrolytes, including high reversible capacity (1300 mA h g-1 at 0.2 A g-1), 84% active material utilization and high rate (capacity up to 900 mA h g-1 at 10 A g-1). These cathodes can undergo 800 cycles with nearly 100% Coulombic efficiency and ultralow 0.029% capacity decay per cycle. Polysulfide dissolution is successfully suppressed by enhanced reaction kinetics. This work demonstrates an ether compatible sulfur cathode involving intermediate Li2Sn (n ≤ 4), attractive rate and cycling performance, and a promising solution towards applicable lithium-sulfur batteries.

Effect of (-)-epicatechin-3-gallate and (-)-epigallocatechin-3-gallate on the binding of tegafur to human serum albumin as determined by spectroscopy, isothermal titration calorimetry, and molecular docking.

Green tea has attracted great interest as a cancer prevention agent. Interactions of tea polyphenols with serum albumin may influence the efficacy of drugs. The interactions of (-)-epigallocatechin-3-gallate (EGCG), (-)-epicatechin-3-gallate (ECG), and tegafur (TF) alone or in combination with human serum albumin (HSA) at pH 7.4 and different temperatures were investigated by spectroscopic methods, isothermal titration calorimetry (ITC), and molecular docking. The binding affinities to HSA were ranked in the order of EGCG > ECG > TF, and the interactions were spontaneous and exothermic. Ternary system studies showed that the presence of one component hindered the binding of another component to HSA. The secondary structures of HSA were slightly altered in the presence of the ligands. Site marking experiments and molecular docking showed that EGCG and ECG mainly bound to subdomain IIA and ΙΙΙA while TF bound to subdomain ΙΙA and ΙB. Results indicated that the existence of ECG and EGCG would influence the binding of TF to HSA and can increase the free concentration of TF. Obtained results would provide beneficial information about possible interference upon simultaneous co-administration of the tea components and drugs. Communicated by Ramaswamy H. Sarma.

Andrographolide Suppresses MV4-11 Cell Proliferation through the Inhibition of FLT3 Signaling, Fatty Acid Synthesis and Cellular Iron Uptake.

Background: Andrographolide (ADR), the main active component of Andrographis paniculata, displays anticancer activity in various cancer cell lines, among which leukemia cell lines exhibit the highest sensitivity to ADR. In particular, ADR was also reported to have reduced drug resistance in multidrug resistant cell lines. However, the mechanism of action (MOA) of ADR's anticancer and anti-drug-resistance activities remain elusive. Methods: In this study, we used the MV4-11 cell line, a FLT3 positive acute myeloid leukemia (AML) cell line that displays multidrug resistance, as our experimental system. We first evaluated the effect of ADR on MV4-11 cell proliferation. Then, a quantitative proteomics approach was applied to identify differentially expressed proteins in ADR-treated MV4-11 cells. Finally, cellular processes and signal pathways affected by ADR in MV4-11 cell were predicted with proteomic analysis and validated with in vitro assays. Results: ADR inhibits MV4-11 cell proliferation in a dose- and time-dependent manner. With a proteomic approach, we discovered that ADR inhibited fatty acid synthesis, cellular iron uptake and FLT3 signaling pathway in MV4-11 cells. Conclusions: ADR inhibits MV4-11 cell proliferation through inhibition of fatty acid synthesis, iron uptake and protein synthesis. Furthermore, ADR reduces drug resistance by blocking FLT3 signaling.

Characterisation of phospholipid: diacylglycerol acyltransferases (PDATs) from Camelina sativa and their roles in stress responses.

As an important oilseed worldwide, Camelina sativa is being increasingly explored for its use in production of food, feed, biofuel and industrial chemicals. However, detailed mechanisms of camelina oil biosynthesis and accumulation, particularly in vegetative tissues, are understood to a very small extent. Here, we present genome-wide identification, cloning and functional analysis of phospholipid diacylglycerol acyltransferase (PDAT) in C. sativa, which catalyses the final acylation step in triacylglycerol (TAG) biosynthesis by transferring a fatty acyl moiety from a phospholipid to diacylglycerol (DAG). We identified five genes (namely CsPDAT1-A, B, and C and CsPDAT2-A and B) encoding PDATs from the camelina genome. CsPDAT1-A is mainly expressed in seeds, whereas CsPDAT1-C preferentially accumulates in flower and leaf tissues. High expression of CsPDAT2-A and CsPDAT2-B was detected in stem and root tissues, respectively. Cold stress induced upregulation of CsPDAT1-A and CsPDAT1-C expression by 3.5- and 2.5-fold, respectively, compared to the control. Salt stress led to an increase in CsPDAT2-B transcripts by 5.1-fold. Drought treatment resulted in an enhancement of CsPDAT2-A mRNAs by twofold and a reduction of CsPDAT2-B expression. Osmotic stress upregulated the expression of CsPDAT1-C by 3.3-fold. Furthermore, the cDNA clones of these CsPDAT genes were isolated for transient expression in tobacco leaves. All five genes showed PDAT enzymatic activity and substantially increased TAG accumulation in the leaves, with CsPDAT1-A showing a higher preference for ɑ-linolenic acid (18:3 ω-3). Overall, this study demonstrated that different members of CsPDAT family contribute to TAG synthesis in different tissues. More importantly, they are involved in different types of stress responses in camelina seedlings, providing new evidence of their roles in oil biosynthesis and regulation in camelina vegetative tissue. The identified CsPDATs may have practical applications in increasing oil accumulation and enhancing stress tolerance in other plants as well.

Competitive binding of (-)-epigallocatechin-3-gallate and 5-fluorouracil to human serum albumin: A fluorescence and circular dichroism study.

Combination therapy with more than one therapeutic agent can improve therapeutic efficiency and decrease drug resistance. In this study, the interactions of human serum albumin (HSA) with individual or combined anticancer drugs, (-)-epigallocatechin-3-gallate (EGCG) and 5-fluorouracil (FU), were investigated by fluorescence and circular dichroism (CD) spectroscopy. The results demonstrated that the interaction of EGCG or FU with HSA is a process of static quenching and EGCG formed a more stable complex. The competitive experiments of site markers suggested that both anti-carcinogens mainly bound to site I (subdomain IIA). The interaction forces which play important roles in the binding process were discussed based on enthalpy and entropy changes. Moreover, the competition binding model for a ternary system was proposed so as to precisely calculate the binding parameters. The results demonstrated that one drug decreased the binding affinity of another drug with HSA, resulting in the increasing free drug concentration at the action sites. CD studies indicated that there was an alteration in HSA secondary structure due to the binding of EGCG and FU. It can be concluded that the combination of EGCG with FU may enhance anticancer efficacy. This finding may provide a theoretical basis for clinical treatments.

Synthesis, characterization, antioxidant activity and neuroprotective effects of selenium polysaccharide from Radix hedysari.

Beta-amyloid (Aß) peptide, the hallmark of Alzheimer's disease, invokes oxidative damage to neurons and eventually leads to neuronal death. Selenylation modification of polysaccharide obtained from Radix hedysari (RHP) was studied to access antioxidant activities and neuroprotective effects against oxidative stress and apoptosis induced by Aß25-35 in vitro. A series of the selenylation derivatives of RHP (Se-RHP) was synthesized using nitric acid-sodium selenite (HNO3-Na2SeO3) method. The organic selenium content of Se-RHP increased from 1.04 to 3.29 mg/g. However, compared with the weight-average molecular mass (Mw) of RHP, Mw of Se-RHP showed a significant decrease, and varied from 27.7 kDa to 62.7 kDa. FT-IR spectra and (13)C NMR spectra indicated the selenite groups had been introduced mainly at the C-6 positions of RHP. Compared with RHP, Se-RHP showed greater antioxidant activities in vitro. Furthermore, both RHP and Se-RHP3 had neuroprotective effects against Aß25-35-induced oxidative stress and apoptosis in SH-SY5Y human neuroblastoma cells, which might be a potential therapeutic agent for preventing or treating neurodegenerative diseases.