Study of nucleic acid-gold nanorod interactions and detecting nucleic acid hybridization using gold nanorod solutions in the presence of sodium citrate

In this study, the authors report that sodium citrate can aggregate hexadecyl-trimethyl-ammonium ion(+)-coated gold nanorods (AuNRs), and nucleic acids of different charge and structure properties, i.e., single-stranded DNA (ssDNA), double-stranded DNA (dsDNA), single-stranded peptide nucleic acid (PNA), and PNA-DNA complex, can bind to the AuNRs and therefore retard the sodium citrate-induced aggregation to different extents. The discovery that hybridized dsDNA (and the PNA-DNA complex) has a more pronounced protection effect than ssDNA (and PNA) allows the authors to develop a homogeneous phase AuNRs-based UV-visible (UV-vis) spectral assay for detecting specific sequences of oligonucleotides (20 mer) with a single-base-mismatch selectivity and a limit of detection of 5 nM. This assay involves no tedious bioconjugation and on-particle hybridization. The simple "set and test" format allows for a highly efficient hybridization in a homogeneous phase and a rapid display of the results in less than a minute. By measuring the degree of reduction in AuNR aggregation in the presence of different nucleic acid samples, one can assess how different nucleic acids interact with the AuNRs to complement the knowledge of spherical gold nanoparticles. Besides UV-vis characterization, transmission electron microscopy and zeta potential measurements were conduced to provide visual evidence of the particle aggregation and to support the discussion of the assay principle.     

Dynamic cellular uptake of mixed-monolayer protected nanoparticles

Nanoparticles (NPs) are gaining increasing attention for potential application in medicine; consequently, studying their interaction with cells is of central importance. We found that both ligand arrangement and composition on gold nanoparticles play a crucial role in their cellular internalization. In our previous investigation, we showed that 66-34OT nanoparticles coated with stripe-like domains of hydrophobic (octanethiol, OT, 34%) and hydrophilic (11-mercaptoundecane sulfonate, MUS, 66%) ligands permeated through the cellular lipid bilayer via passive diffusion, in addition to endo-/pino-cytosis. Here, we show an analysis of NP internalization by DC2.4, 3T3, and HeLa cells at two temperatures and multiple time points. We study four NPs that differ in their surface structures and ligand compositions and report on their cellular internalization by intracellular fluorescence quantification. Using confocal laser scanning microscopy we have found that all three cell types internalize the 66-34OT NPs more than particles coated only with MUS, or particles coated with a very similar coating but lacking any detectable ligand shell structure, or 'striped' particles but with a different composition (34-66OT) at multiple data points.     

PTP1B Inhibitory and Anti-Inflammatory Effects of Secondary Metabolites Isolated from the Marine-Derived Fungus Penicillium sp. JF-55

Protein tyrosine phosphatase 1B (PTP1B) plays a major role in the negative regulation of insulin signaling, and is thus considered as an attractive therapeutic target for the treatment of diabetes. Bioassay-guided investigation of the methylethylketone extract of marine-derived fungus Penicillium sp. JF-55 cultures afforded a new PTP1B inhibitory styrylpyrone-type metabolite named penstyrylpyrone (1), and two known metabolites, anhydrofulvic acid (2) and citromycetin (3). Compounds 1 and 2 inhibited PTP1B activity in a dose-dependent manner, and kinetic analyses of PTP1B inhibition suggested that these compounds inhibited PTP1B activity in a competitive manner. In an effort to gain more biological potential of the isolated compounds, the anti-inflammatory effects of compounds 1–3 were also evaluated. Among the tested compounds, only compound 1 inhibited the production of NO and PGE₂, due to the inhibition of the expression of iNOS and COX-2. Penstyrylpyrone (1) also reduced TNF-α and IL-1β production, and these anti-inflammatory effects were shown to be correlated with the suppression of the phosphorylation and degradation of IκB-α, NF-κB nuclear translocation, and NF-κB DNA binding activity. In addition, using inhibitor tin protoporphyrin (SnPP), an inhibitor of HO-1, it was verified that the inhibitory effects of penstyrylpyrone (1) on the pro-inflammatory mediators and NF-κB DNA binding activity were associated with the HO-1 expression. Therefore, these results suggest that penstyrylpyrone (1) suppresses PTP1B activity, as well as the production of pro-inflammatory mediators via NF-κB pathway, through expression of anti-inflammatory HO-1.     

Comparative cytotoxicity evaluation of lanthanide nanomaterials on mouse and human cell lines with metabolic and DNA-quantification assays

Lanthanide nanomaterials are considered a less toxic alternative to quantum dots for bioimaging applications. This study evaluated the cytotoxicity of terbium (Tb)-doped gadolinium oxide (Gd(2)O(3)) and dysprosium oxide (Dy(2)O(3)) nanoparticles exposed to human (BEAS-2B) and mouse (L929) cell lines at a concentration range of 200-2000?μg/ml for 48 h. Two assay methods were utilized-WST-8 assay (colorimetric) based on mitochondrial metabolic activity and Pico-Green assay (fluorescence), which measures total DNA content. The authors' data showed that Tb-doped Gd(2)O(3) nanoparticles were consistently more toxic than Tb-doped Dy(2)O(3) nanoparticles. However, exposure to these nanomaterials caused a decrease in proliferation rate for both cell lines rather than a net loss of viable cells after 48 h of exposure. Additionally, there was some degree of discrepancy observed with the two assay methods. For the mouse L929 cell line, the WST-8 assay yielded consistently lower proliferation rates compared to the Pico-Green assay, whereas the opposite trend was observed for the human BEAS-2B cell line. This could arise because of the differential effects of these nanoparticles on the metabolism of L929 and BEAS-2B cells, which in turn may translate to differences in their postexposure proliferation rates. Hence, the Pico-Green assay could have an advantage over the WST-8 assay because it is not skewed by the differential effects of nanomaterials on cellular metabolism.     

The Cytoprotective Effect of Petalonia binghamiae Methanol Extract against Oxidative Stress in C2C12 Myoblasts: Mediation by Upregulation of Heme Oxygenase-1 and Nuclear Factor-Erythroid 2 Related Factor 2

This study was designed to examine the protective effects of the marine brown algae Petalonia binghamiae against oxidative stress-induced cellular damage and to elucidate the underlying mechanisms. P. binghamiae methanol extract (PBME) prevented hydrogen peroxide (H₂O₂)-induced growth inhibition and exhibited scavenging activity against intracellular reactive oxygen species (ROS) induced by H₂O₂ in mouse-derived C2C12 myoblasts. PBME also significantly attenuated H₂O₂-induced comet tail formation in a comet assay, histone γH2A.X phosphorylation, and annexin V-positive cells, suggesting that PBME prevented H₂O₂-induced cellular DNA damage and apoptotic cell death. Furthermore, PBME increased the levels of heme oxygenase-1 (HO-1), a potent antioxidant enzyme, associated with the induction of nuclear factor-erythroid 2 related factor 2 (Nrf2). However, zinc protoporphyrin IX, a HO-1 competitive inhibitor, significantly abolished the protective effects of PBME on H₂O₂-induced ROS generation, growth inhibition, and apoptosis. Collectively, these results demonstrate that PBME augments the antioxidant defense capacity through activation of the Nrf2/HO-1 pathway.     

Protective Effect of Flavonoids from a Deep-Sea-Derived Arthrinium sp. against ox-LDL-Induced Oxidative Injury through Activating the AKT/Nrf2/HO-1 Pathway in Vascular Endothelial Cells

Oxidized low-density lipoprotein (ox-LDL)-induced oxidative injury in vascular endothelial cells is crucial for the progression of cardiovascular diseases, including atherosclerosis. Several flavonoids have been shown cardiovascular protective effects. Recently, our research group confirmed that the novel flavonoids isolated from the deep-sea-derived fungus Arthrinium sp., 2,3,4,6,8-pentahydroxy-1-methylxanthone (compound 1) and arthone C (compound 2) effectively scavenged ROS in vitro. In this study, we further investigated whether these compounds could protect against ox-LDL-induced oxidative injury in endothelial cells and the underlying mechanisms. Our results showed that compounds 1 and 2 inhibited ox-LDL-induced apoptosis and adhesion factors expression in human umbilical vein vascular endothelial cells (HUVECs). Mechanistic studies showed that these compounds significantly inhibited the ROS level increase and the NF-κB nuclear translocation induced by ox-LDL. Moreover, compounds 1 and 2 activated the Nrf2 to transfer into nuclei and increased the expression of its downstream antioxidant gene HO-1 by inducing the phosphorylation of AKT in HUVECs. Importantly, the AKT inhibitor MK-2206 2HCl or knockdown of Nrf2 by RNA interference attenuated the inhibition effects of these compounds on ox-LDL-induced apoptosis in HUVECs. Meanwhile, knockdown of Nrf2 abolished the effects of the compounds on ox-LDL-induced ROS level increase and the translocation of NF-κB to nuclei. Collectively, the data showed that compounds 1 and 2 protected endothelial cells against ox-LDL-induced oxidative stress through activating the AKT/Nrf2/HO-1 pathway. Our study provides new strategies for the design of lead compounds for related cardiovascular diseases treatment.     

Preparation of Durable Antibacterial Cellulose with AgCl Nanoparticles

In this study, a facile method was developed to coat AgCl nanoparticles (NPs) onto knitted cotton fabrics. The AgCl NPs were characterized by ultraviolet absorption spectrum, X-ray diffraction (XRD) and dynamic laser light scattering (DLS). The AgCl NPs were coated onto cotton fabrics through a pad-dry-cure process with the assistance of 1,2,3,4- butanetetracarboxylic acid (BTCA). Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), ICP-OES analysis and energy-dispersive X-ray spectroscopy (EDX) confirmed that AgCl NPs were successfully coated onto cotton fabrics. The prepared cotton samples exhibited excellent antimicrobial activity against both Gram-positive S. aureus and Gram-negative K. pneumonia bacteria. Rat skin fibroblast cytotoxicity testing demonstrated the treated cotton fabrics to be non-toxic. The washing durability evaluation showed that the antimicrobial function of cotton fabrics was durable to washing. In addition, the wrinkle resistance of the coated cotton fabrics was improved and there was no obvious change in whiteness.     

Immunomodulatory and Antitumoral Activity of Gold Nanoparticles Synthesized by Red Algae Aqueous Extracts

This study reports on the green and cost-efficient synthesis of gold nanoparticles from three different red algae extracts. The nanoparticles synthesized were fully characterized by UV-Vis spectroscopy, HRTEM, and Z-potential. Relevant components occurring in the extracts, such as polysaccharides or phenolic content, were assessed by analytical techniques such as spectrophotometric assays and liquid chromatography. Finally, the antioxidant, antitumoral, and anti-inflammatory potential of both the extracts and the gold nanoparticles synthesized were analyzed in order to determine a possible synergistic effect on the nanoparticles. The results obtained confirmed the obtainment of gold nanoparticles with significant potential as immunotherapeutic agents. The therapeutic potential of these nanoparticles could be higher than that of inert gold nanoparticles loaded with bioactive molecules since the former would allow for higher accumulation into the targeted tissue.     

茶黄素激活Nrf2/HO-1通路保护血管内皮细胞氧化应激损伤

为探讨茶黄素（Theaflavin,TF）对过氧化氢（H₂O₂）诱导的血管内皮细胞氧化应激损伤的保护效应及作用机制,将人脐静脉血管内皮细胞HUVEC分为对照组、损伤组（0.2 mmol·L^-1 H₂O₂处理）和TF预处理组（2.0、5.0、10.0 μmol·L^-1 TF和0.2 mmol·L^-1 H₂O₂处理）。损伤组和TF组均以H₂O₂处理24 h,其中TF组先以不同浓度TF预处理2 h,对照组均以定量溶剂处理。以MTT法测定细胞活力,DCFH-DA探针测定活性氧（ROS）水平,流式细胞术检测细胞凋亡,Western blot测定蛋白表达水平,相应试剂盒测定乳酸脱氢酶（LDH）、一氧化氮（NO）、丙二醛（MDA）含量及超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、谷胱甘肽过氧化氢酶（GSH-Px）活性。结果显示,与对照组相比,损伤组细胞活力显著降低,LDH释放量增加,NO水平降低,胞内ROS水平升高,MDA增加,抗氧化酶活力降低,细胞凋亡升高;TF预处理能够显著提高细胞活力,降低LDH水平,维持NO水平,降低胞内ROS水平及MDA的产生,提高抗氧化酶活力,并抑制细胞凋亡;进一步研究显示,TF能够激活Nrf2/HO-1通路,且Nrf2抑制剂会显著降低TF的内皮细胞保护效应。可见,TF能够有效抑制H₂O₂诱导的血管内皮细胞氧化应激损伤,其机制至少部分是通过激活Nrf2/HO-1通路实现的。     

Chitosan nanoparticles act as an adjuvant to promote both Th1 and Th2 immune responses induced by ovalbumin in mice

The study was conducted to investigate the promoted immune response to ovalbumin in mice by chitosan nanoparticles (CNP) and its toxicity. CNP did not cause any mortality or side effects when mice were administered subcutaneously twice with a dose of 1.5 mg at 7-day intervals. Institute of Cancer Research (ICR) mice were immunized subcutaneously with 25 μg ovalbumin (OVA) alone or with 25 μg OVA dissolved in saline containing Quil A (10 μg), chitosan (CS) (50 μg) or CNP (12.5, 50 or 200 μg) on days 1 and 15. Two weeks after the secondary immunization, serum OVA-specific antibody titers, splenocyte proliferation, natural killer (NK) cell activity, and production and mRNA expression of cytokines from splenocytes were measured. The serum OVA-specific IgG, IgG1, IgG2a, and IgG2b antibody titers and Con A-, LPS-, and OVA-induced splenocyte proliferation were significantly enhanced by CNP (P < 0.05) as compared with OVA and CS groups. CNP also significantly promoted the production of Th1 (IL-2 and IFN-γ) and Th2 (IL-10) cytokines and up-regulated the mRNA expression of IL-2, IFN-γ and IL-10 cytokines in splenocytes from the immunized mice compared with OVA and CS groups. Besides, CNP remarkably increased the killing activities of NK cells activity (P < 0.05). The results suggested that CNP had a strong potential to increase both cellular and humoral immune responses and elicited a balanced Th1/Th2 response, and that CNP may be a safe and efficacious adjuvant candidate suitable for a wide spectrum of prophylactic and therapeutic vaccines.     

An HPLC Method for Microanalysis and Pharmacokinetics of Marine Sulfated Polysaccharide PSS-Loaded Poly Lactic-co-Glycolic Acid (PLGA) Nanoparticles in Rat Plasma

This study was aimed at developing a sensitive and selective HPLC method with postcolumn fluorescence derivatization for the detection of propylene glycol alginate sodium sulfate (PSS) in rat plasma. Plasma samples were prepared by a simple and fast ultrafiltration method. PSS was extracted from rat plasma with d-glucuronic acid as internal standard. Isocratic chromatographic separation was performed on a TSKgel G2500 PWxL column with the mobile phase of 0.1 M sodium sulfate at a flow rate of 0.5 mL/min. Analyte detection was achieved by fluorescence detection (FLD) at 250 nm (excitation) and 435 nm (emission) using guanidine hydrochloride as postcolumn derivatizing reagent in an alkaline medium at 120 °C. The calibration curve was linear over a concentration range of 1–500 μg/mL, and the lower limit of detection (LLOD) was found to be 250 ng/mL. This validated method was applied successfully to the pharmacokinetic study of PSS and PSS-loaded poly lactic-co-glycolic acid (PLGA) nanoparticles (PSS-NP) in rat plasma after a single intravenous (PSS only) and oral administration (PSS and PSS-NP). Significant differences in the main pharmacokinetic parameters of PSS and PSS-NP were observed. The relative bioavailability of PSS-NP was 190.10% compared with PSS which shows that PSS-NP can improve oral bioavailability.     

Production of a Novel Fucoidanase for the Green Synthesis of Gold Nanoparticles by Streptomyces sp. and Its Cytotoxic Effect on HeLa Cells

Marine actinobacteria-produced fucoidanases have received considerable attention as one of the major research topics in recent years, particularly for the medical exploitation of fucoidans and their degradation products. The present study describes the optimization and production of a novel fucoidanase for the green synthesis of gold nanoparticles and its biological applications. The production of fucoidanase was optimized using Streptomyces sp. The medium components were selected in accordance with the Plackett-Burman design and were further optimized via response surface methodology. The fucoidanase was statistically optimized with the most significant factors, namely wheat bran 3.3441 g/L, kelp powder 0.7041 g/L, and NaCl 0.8807 g/L, respectively. The biosynthesized gold nanoparticles were determined by UV-vis spectroscopy and were further characterized by X-ray diffraction analysis, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, energy dispersive X-ray analysis, and high-resolution transmission electron microscopy. Furthermore, the biosynthesized gold nanoparticles exhibited a dose-dependent cytotoxicity against HeLa cells and the inhibitory concentration (IC₅₀) was found to be 350 µg/mL at 24 h and 250 µg/mL at 48 h. Therefore, the production of novel fucoidanase for the green synthesis of gold nanoparticles has comparatively rapid, less expensive and wide application to anticancer therapy in modern medicine.     

Gold recovery using inherently conducting polymer coated textiles

The ability of inherently conducting polymer (ICP) coated textiles to recover gold metal from aqueous solutions containing [AuCl₄]⁻ was investigated. Nylon-lycra, nylon, acrylic, polyester and cotton were coated with a layer of polypyrrole (PPy) doped with 1,5-naphthalenedisulfonic acid (NDSA), 2-anthraquinonesulfonic acid (AQSA) orp-toluenesulfonic acid (pTS). Textiles coated with polyaniline (PAn) doped with chloride were also used. The highest gold capacity was displayed by PPy/NDSA/nylon-lycra, which exhibited a capacity of 115 mg Au/g coated textile, or 9700 mg Au/g polymer. Varying the underlying textile substrate or the ICP coating had a major effect on the gold capacity of the composites. Several ICP coated textiles recovered more than 90% of the gold initially present in solutions containing 10 ppm [AuCl₄]⁻ and 0.1 M HCl in less than 1 min. Both PPy/NDSA/nylon-lycra and PAn/Cl/nylon-lycra recovered approximately 60% of the gold and none of the iron present in a solution containing 1 ppm [AuCl₄]⁻, 1000 ppm Fe³⁺ and 0.1 M HCl. The spontaneous and sustained recovery of gold metal from aqueous solutions containing [AuCl₄]⁻ using ICP coated textiles has good prospects as a potential future technology.     

辣椒DNA甲基化修饰酶基因的鉴定与表达特征分析

DNA甲基化与去甲基化是表观遗传修饰中一种保守的分子机制,参与植物生长发育、次生代谢和逆境胁迫响应等多种生物过程,受DNA甲基化修饰酶基因的调控.为了解DNA甲基化修饰酶基因在辣椒基因组中的特征,利用生物信息学手段鉴定出14个辣椒DNA甲基转移酶和去甲基化酶基因,并对其进行系统分析.结果表明:辣椒基因组中含10个DNA...