Patulin induces ROS-dependent cardiac cell toxicity by inducing DNA damage and activating endoplasmic reticulum stress apoptotic pathway.

Patulin (PAT) is one of the mycotoxins commonly found in agricultural products and fruits, and has obvious toxic effects on animals and humans. PAT has been found to cause myocardial toxicity and oxidative damage, but the mechanism of myocardial toxicity remained to be elucidated. We investigated the toxic effects and potential mechanisms of PAT on human cardiomyocytes and explored the effects of reactive oxygen species (ROS) on them. The study showed that treatment with PAT for 24 h decreased cell viability and superoxide dismutase (SOD) activity, and increased ROS and lactate dehydrogenase (LDH) levels. Moreover, in addition to detecting increased γ-H2AX expression and observing nuclear damage, the comet assay also showed increased DNA tail distance in the PAT-treated group, followed by an increase in phosphorylation of the p53 protein and p21 protein expression, and a decrease in CDK1 and Cyclin B1 protein expression, and G2/M phase arrest. In addition, PAT induced endoplasmic reticulum stress (ERS) and induced apoptosis, as evidenced by Ca2+ increase, ER enlargement and swelling, and upregulation of ERS-related genes and proteins expression, and increased expression of three apoptotic pathway proteins under ERS, including CHOP, JNK, and caspase-12. Meanwhile, N-acetylcysteine (NAC, a ROS scavenger) reversed the negative effects of PAT treatment on cells. These results clarify that excessive ROS production by PAT-treated AC16 cells not only causes DNA damage, leading to cell cycle arrest, but also causes ERS, which triggers apoptotic pathways to cause apoptosis.

Effect and mechanism of Fisetin on myocardial damage induced by Patulin.

OBJECTIVES OF THE STUDY: The aim of this study is to investigate whether fisetin can effectively reduce the myocardial damage induced by patulin. This study also aims to reveal the mechanism and target of fisetin in inhibiting myocardial damage. MATERIALS AND METHODS: Network pharmacology was used to screen the targets of fisetin on myocardial damage and the regulatory network of active ingredients-drug targets was constructed. GO and KEGG enrichment analyses were performed to screen out the key pathways and targets of fisetin on myocardial damage. Patulin induced apoptosis in H9c2 cardiomyocytes to verify the key targets. The mechanism of fisetin in inhibiting myocardial damage was determined. RESULTS: FIS can reduce the apoptosis of cardiomyocytes by protecting cardiomyocytes from PAT injury. According to the results of network pharmacology analysis, combined with enzyme activity detection and WB experiment, it was found that the mechanism of FIS to reduce myocardial damage may be related to the P53 signaling pathway, Caspase3/8/9 and Bax/Bcl-2. CONCLUSION: FIS plays a protective role in PAT-induced myocardial damage. On the one hand, FIS inhibits the protein overexpression of P53, Caspase-9 and Bax. On the other hand, FIS enhances the protein expression of Bcl-2.

Toxicity mechanism of patulin on 293 T cells and correlation analysis of Caspase family.

Patulin (PAT), a kind of mycotoxin, is a widely disseminated mycotoxin found in agricultural products. Although the existing research results show that PAT can cause nerve, immune, and skin toxicities, resulting in heart, liver, and kidney damages. However, evidence on the underlying mechanisms of PAT is still lacking. Present study aims to investigate the renal toxicity and related mechanisms of PAT on 293 T cells. Cell Counting Kit-8 method was used to reveal the dose-effect relationship and the time-effect relationship of PAT toxicity. Trypan blue staining and Hoechst 33342 staining were used to analyze PAT, which induced apoptosis on 293 T cells. Superoxide-dismutase (SOD), GSH, and malondialdehyde (MDA) were used to measure the changes of oxidative stress status of 293 T cells induced by PAT. The changes of reactive oxygen species (ROS) and ATP in mitochondria indicate the role of mitochondria when PAT induced cell damage and apoptosis. Through Cyt-C release assay analysis, caspase activity change, and correlation analysis, the potential mechanism of mitochondrial apoptosis pathway was proved. Results demonstrated that PAT significantly induced cell injury, and with the increase of time and concentration, the cell survival rate decreased significantly. Hoechst 33342 staining and Trypan blue staining showed that apoptosis rate was elevated by PAT. As PAT concentration increased, intracellular SOD, glutathion peroxidase activities were decreased and the MDA content was increased. The decrease of intracellular ATP level and accumulation of ROS content indicated an increased permeability of the mitochondrial membrane. Overexpression of Cyt-C activated the cascade reaction of caspase enzyme, leading to apoptosis. The results of enzyme activity assay and correlation analysis indicated that caspase 3 was the most critical caspase in the cascade system and that it was most correlated with caspase 8 and caspase 9.

Involvement of caspase in patulin-induced hepatotoxicity in vitro and in vivo.

Patulin (PAT) a kind of mycotoxin, is a widely disseminated mycotoxin found in agricultural products and could cause liver damage. However, evidence on the underlying mechanisms of patulin is still lacking. In the present study, Human liver cancer cells (HepG2) together with a mouse model were used to explore the possible effect and mechanism. The results demonstrated that PAT treatment inhibited cell proliferation and caused liver toxicity in mice. In vitro, PAT inhibited the growth of HepG2 cells in a dose-dependent manner and a time-dependent manner; lipid peroxidation, malondialdehyde (MDA) production increased and the level of SOD and GSH in cells changed significantly. In vivo, Kunming mice were treated with PAT(2.5-15 µM), We indicated that liver damage are observed. The activity of serum alanine transaminase (ALT) and aspartate transaminase (AST) were increased significantly, the hepatocyte nucleus stained with Hematoxylin and Eosin (HE) was blurred and deformed. we also explored the lipid peroxidation and enzymes related to redox and found that the activities of SOD in animals do not change significantly, not like that in cells, while GSHpx played a major role. In addition, we measured the caspase activity of cells and the expression of caspase in mice. PAT-induced the caspase cascade was confirmed with the elevation of the activity and expression of caspase. These data suggest that PAT treatment altered both the redox systems in cells and animals. involvement of caspase in patulin-induced hepatotoxicity.

Cardiotoxicity of patulin was found in H9c2 cells.

Patulin (PAT) is a kind of mycotoxins that is universally found at rotten fruits, especially apples and apple products. Previous studies have shown that PAT has hepatotoxicity and nephrotoxicity. However, cardiotoxicity of PAT is rarely reported. Present study aimed at investigate the cardiotoxicity and relevant mechanisms of PAT on H9c2 cells. Cytotoxicity of PAT were evaluated by MTT assay and LDH. Hoechst 33258 staining was used to examine the nuclear morphology and AV/PI double staining was employed for apoptosis on H9c2 cells. Expression level of Caspase-3, Caspase-9, Bax, Bcl-2 were quantified to verify the potential mechanism of mitochondrial apoptosis pathway. The tumor necrosis factor alpha (TNF-α), interleukin-1ß (IL-1ß), and interleukin 6 (IL-6) were quantified to determine the inflammatory response by using ELISA assay. ROS, SOD, MDA, GSH levels were measured to determine the oxidative stress status. Results demonstrated that PAT significantly induced cell injury, as evidenced by the down-regulated of cell viability, and the increase of LDH release. Hoesst33258 staining and flow cytometry showed that apoptosis rate was elevated by PAT. PAT treatment up-regulated the expression of Caspase-3, Caspase-9, Bax level and down-regulated the expression of Bcl-2 level. TNF-α, IL-1ß, IL-6 levels showed that PAT increased the pro-inflammatory response. As PAT concentration increased, intracellular MDA, ROS content were elevated, while GSH content and the activity of SOD were significantly decreased. Thus, it is concluded that PAT may induce apoptosis of H9c2 cells through oxidative stress.

Structural characteristics of polysaccharide microcapsules fromNostoc commune,and their applications in skin wound healing and pathological repair.

In this study, the extraction conditions ofNostoc communeVauch polysaccharide (NCVP) were optimized by single factor and orthogonal experiments. Then, the NCVP microcapsules (NCVPM) were prepared. After analyzing the microcapsule structural and thermal characteristics, the skin wound healing ability was studied by establishing back trauma rat models. Results showed that the NCVP yield was 10.37% under the following optimum conditions: 210 min extraction time, solid-liquid ratio of 1:50 and extraction temperature of 90 °C. The overall performance of the microcapsule was the best when the concentration of sodium alginate, calcium chloride and chitosan was 2%, 3% and 0.3%, respectively. NCVPM had spherical morphology, typical microcapsule structural characteristics and good thermal stability, and NCVP was dispersed in the microcapsules. NCVPM showed good biocompatibility and biodegradability, which met the requirements for slow-release polymer materials. After 14 days of treatment, the wound healing rate was 92.4%, the cells were arranged neatly and regularly, the cell nucleus became large and elliptical, the cell had a tendency to divide, and the fibers and microvessel were significantly more. By evaluating the mechanism, NCVPM could increase the content of hydroxyproline and glutathione to protect cells from oxidative damage, leading in turn to accelerated wound healing and shorter wound healing times. It could also accelerate cell division, collagen and microvascular production by increasing transcription levels of vascular endothelial growth factor mRNA and miRNA-21.

Preparation, characterization and wound healing effect of alginate/chitosan microcapsules loaded with polysaccharides from Nostoc Commune Vaucher.

Biologically active coating materials could promote the growth of granulation tissue as auxiliary materials, while natural polysaccharides could promote vascular regeneration and wound healing. Therefore, in this study, ultrasound-assisted extract of Nostoc commune Vaucher polysaccharides (UAP) yield after the process optimization was 12.89 ± 0.24%, which was used to prepare microcapsules by emulsification and cross-linking. The effect of alginate/chitosan-UAP composite materials on wound healing in an experimental rat model for 14 d and its physical properties were evaluated. In vitro experiments indicated that the UAP microcapsule material had a porous and loose three-dimensional network structure, and had good biocompatibility and swelling properties as a wound healing material. Animal experiments indicated that UAP microcapsules could extremely significantly promote wound healing (P < 0.01), and wound closure rate reached 79.16 ± 3.91% on 14th day. Meanwhile UAP microcapsules might promote angiogenesis and granulation growth by enhancing immunity and increasing the expression of VEGF and miR-21. Therefore, the composites of UAP microcapsules have shown encouraging results as a potential dressing for wound healing.

Smartphone based optical spectrometer for diffusive reflectance spectroscopic measurement of hemoglobin.

We report a miniature, visible to near infrared G-Fresnel spectrometer that contains a complete spectrograph system, including the detection hardware and connects with a smartphone through a microUSB port for operational control. The smartphone spectrometer is able to achieve a resolution of ~5 nm in a wavelength range from 400 nm to 1000 nm. We further developed a diffuse reflectance spectroscopy system using the smartphone spectrometer and demonstrated the capability of hemoglobin measurement. Proof of concept studies of tissue phantoms yielded a mean error of 9.2% on hemoglobin concentration measurement, comparable to that obtained with a commercial benchtop spectrometer. The smartphone G-Fresnel spectrometer and the diffuse reflectance spectroscopy system can potentially enable new point-of-care opportunities, such as cancer screening.

Prevalence, distribution, and diversity of Escherichia coli in plants manufacturing goat milk powder in Shaanxi, China.

The aim of the study was to investigate the prevalence, distribution, and diversity of Escherichia coli in goat-milk-powder plants in Shaanxi, China. Three plants manufacturing goat milk powder in Shaanxi province were visited once for sampling during 2012 and 2013. Samples were taken for isolation of E. coli. Isolates were characterized by antimicrobial susceptibility testing and detection of virulence genes. All isolates were further examined by pulsed-field gel electrophoresis analysis. In total, 53 E. coli strains were isolated from 32 positive samples out of 534 samples. Among E. coli isolates, resistance was most frequently observed to trimethoprim-sulfamethoxazole (75.5%), whereas all isolates were sensitive to gatifloxacin, kanamycin, amikacin, and amoxicillin-clavulanate. The 6 virulence genes of pathogenic E. coli were not detected. Pulsed-field gel electrophoresis results showed that E. coli strains in plants were genetically diverse and milk storage tank could be an important contamination source. This study could provide useful information for plants manufacturing goat milk powder to establish proper management practices that help minimize the chance of microbial contamination.

Tannin-rich pomegranate rind extracts reduce adhesion to and invasion of Caco-2 Cells by Listeria monocytogenes and decrease its expression of virulence genes.

Pomegranate rind is rich in tannins that have remarkable antimicrobial activities. This study aimed to evaluate the effects of a tannin-rich fraction from pomegranate rind (TFPR) on Listeria monocytogenes virulence gene expression and on the pathogen's interaction with human epithelial cells. Growth curves were monitored to determine the effect of TFPR on L. monocytogenes growth. The 3-(4,5-dimethylthiazol-2-yl)2,5-diphenyltetrazolium bromide and fluorescence staining assays were used to examine the cytotoxicity of TFPR. The effects of TFPR on L. monocytogenes adhesion to and invasion of epithelial cells were investigated using Caco-2 cells. Real-time quantitative PCR analysis was conducted to quantify mRNA levels of three virulence genes in L. monocytogenes. Results showed that a MIC of TFPR against L. monocytogenes was 5 mg/ml in this study. TFPR exhibited cytotoxicity against Caco-2 cells when the concentration was 2.5 mg/ml. Subinhibitory concentrations of TFPR significantly reduced, in a dose-dependent manner, adhesion to and invasion of Caco-2 cells by L. monocytogenes. When L. monocytogenes was grown in the presence of 2.5 mg/ml TFPR, the transcriptional levels of prfA, inlA, and hly decreased by 17-, 34-, and 28-fold, respectively.

Oxidative stress is involved in Patulin induced apoptosis in HEK293 cells.

Patulin (PAT) is one of the most widely disseminated mycotoxins found in agricultural products and could cause renal damage. However, the mechanism of cell damage remains obscure. In this study, the human embryonic kidney cells (HEK293) were treated with PAT (2.5-15 µM). The cytotoxicity was assessed with MTT assay and apoptotic cells were detected by flow cytometry, and further identified by chromatin condensation and nuclear fragmentation with Hoechst 33342 under fluorescence microscope. Reactive oxygen species (ROS) with DCFH-DA was analyzed by fluorometry. The activities of superoxide dismutase (SOD), glutathione (GSH) and catalase (CAT) and malondialdehyde (MDA) content were determined to reveal the potential mechanism of PAT induced apoptosis. The mitochondrial membrane potential was measured by JC-1 probe. The results showed that PAT dose-dependently inhibited the growth of HEK293 cells and resulted in apoptosis in HEK293 cells. Treatment with PAT could induce ROS and MDA accumulation, accompanied by the losses of SOD, CAT, GSH and disruption of the mitochondrial membrane potential. These data suggest that PAT may induce apoptosis in HEK293 cells, in which oxidative stress is involved.

Mid-infrared spectroscopic imaging enabled by an array of Ge-filled waveguides in a microstructured optical fiber probe.

We demonstrate mid-infrared spectroscopic imaging using a unique optical fiber probe consisting of an array of Ge waveguide cores embedded in a silica fiber matrix. Biological tissue slices are characterized to illustrate its potential endoscopic uses. The fiber probe based transmission measurements show excellent agreement with the result obtained from standard Fourier Transform Infrared spectroscopy transmission measurements in the wavelength range of 3289.8 nm to 3383.3 nm, where fat and muscle tissues could be spectroscopically distinguished.

Fluorescence lifetime based characterization of active and tunable plasmonic nanostructures.

We report a non-contact method that utilizes fluorescence lifetime (FL) to characterize morphological changes of a tunable plasmonic nanostructure with nanoscale accuracy. The key component of the plasmonic nanostructure is pH-responsive polyelectrolyte multilayers (PEMs), which serve as a dynamically tunable "spacer" layer that separates the plasmonic structure and the fluorescent materials. The validity of our method is confirmed through direct comparison with ellipsometry and atomic force microscopy (AFM) measurements. Applying the FL-based approach, we find that a monolayer polycation film responds to pH changes with significantly less hysteresis than a thicker multilayer film with polyelectrolytes of both charges. Additionally, we characterize an active and tunable plasmonic nanostructure composed of self-assembled fluorescent dye (Texas Red), pH-sensitive PEMs, and gold nanospheres adsorbed on the PEM surface. Our results point towards the possibility of using stimulus-sensitive polymers to construct active and tunable plasmonic nanodevices.

Impact of lithography on the fluorescence dynamics of self-assembled fluorophores.

Micro- and nano-patterned fluorescent materials are important for many photonic devices and applications. In this paper, we investigate the impact of three common lithographical techniques, deposition and removal of sacrificial masks, ultraviolet ablation, and focused ion beam milling, on self-assembled fluorophores. We find that different patterning techniques can dramatically change the fluorescence lifetime of the fluorophores and that the degree of modification depends on the patterning techniques.

Tannin-rich fraction from pomegranate rind damages membrane of Listeria monocytogenes.

Pomegranate rind has been reported to inhibit several foodborne pathogens, and its antimicrobial activity has been attributed mainly to its tannin fraction. This study aimed to investigate the antimicrobial activity of the tannin-rich fraction from pomegranate rind (TFPR) against Listeria monocytogenes and its mechanism of action. The tannin-related components of TFPR were analyzed by high-performance liquid chromatography and liquid chromatography-mass spectrometry, and the minimum inhibitory concentration (MIC) of TFPR was determined using the agar dilution method. Extracellular potassium concentration, the release of cell constituents, intra- and extracellular ATP concentrations, membrane potential, and intracellular pH (pHin) were measured to elucidate a possible antibacterial mechanism. Punicalagin (64.2%, g/g) and ellagic acid (3.1%, g/g) were detected in TFPR, and the MICs of TFPR were determined to be 1.25-5.0 mg/mL for different L. monocytogenes strains. Treatment with TFPR induced a decrease of the intracellular ATP concentration, an increase of the extracellular concentrations of potassium and ATP, and the release of cell constituents. A reduction of pHin and cell membrane hyperpolarization were observed after treatment. Electron microscopic observations showed that the cell membrane structures of L. monocytogenes were apparently impaired by TFPR. It is concluded that TFPR could destroy the integrity of the cell membrane of L. monocytogenes, leading to a loss of cell homeostasis. These findings indicate that TFPR has the potential to be used as a food preservative in order to control L. monocytogenes contamination in food and reduce the risk of listeriosis.

High quality factor silica microspheres functionalized with self-assembled nanomaterials.

With extremely low material absorption and exceptional surface smoothness, silica-based optical resonators can achieve extremely high cavity quality (Q) factors. However, the intrinsic material limitations of silica (e.g., lack of second order nonlinearity) may limit the potential applications of silica-based high Q resonators. Here we report some results in utilizing layer-by-layer self-assembly to functionalize silica microspheres with nonlinear and plasmonic nanomaterials while maintaining Q factors as high as 10(7). We compare experimentally measured Q factors with theoretical estimates, and find good agreement.

Experimental study on a high conversion efficiency, low threshold, high-repetition-rate periodically poled lithium niobate optical parametric generator.

A high-conversion-efficiency, low-threshold, quasi-continuous-wave optical parametric generator (OPG) based on a periodically poled lithium niobate (PPLN) crystal is presented. Pumped by an acousto-optically Q-switched 1064 nm Nd:YAG laser with a power output of 848 mW, the OPG generated an output power of 452 mW for the signal and the idle waves, achieving an internal conversion efficiency of 62.7% and a slope efficiency of 75.6%. To the best of our knowledge, this is the highest efficiency ever reported for single-pass, quasi-continuous-wave OPGs by using periodically poled crystals.

Design of a broadband source by using the retracing behavior of a collinear quasi-phase-matching optical parametric generator.

In this paper, we introduce a concept of phase matching bandwidth of broadband sources by using the retracing behavior of collinear quasi-phase-matching (CQPM) optical parametric generation (OPG) in periodically poled lithium niobate (PPLN). By comparing various pump wavelengths we derive the pumping condition and parameters of PPLN to realize a broadband source near 1550 nm in the CQPM-OPG. We predict the optimum pump wavelength and the maximum ideal bandwidth range to be 940.75 nm and 1475-1681 nm respectively. Experimentally we have demonstrated a 946 nm Nd:YAG laser which serves as the pumping source of CQPM-OPG.

Continuous-wave operation at 1386 nm in a diode-end-pumped Nd:YVO4 laser.

We report a diode-end-pumped continuous wave (cw) Nd:YVO4 laser operation at 1386 nm. A maximum output power of 305 mW is achieved at an incident pump power of 4.24 W, achieving a slope efficiency of 13.9%. To the best of our knowledge, this is the first time that cw operation at this transition of Nd:YVO4 crystal is reported. By using the experimentally measured threshold data, the stimulated-emission cross-section of this gain medium at 1386 nm transition is determined to be 3x10- 19cm2. In addition, simultaneous cw operation at 1342 nm and 1386 nm is also observed.

8.3 W diode-end-pumped continuous-wave Nd:YAG laser operating at 946-nm.

This paper reports a diode-end-pumped continuous-wave (CW) Nd:YAG laser operating at 946-nm by utilizing the 4F3/2-4I9/2 transition. We demonstrated that at an incident pump power of 27.7 W, an output power of 8.3-W could be achieved with a slope efficiency of 33.5%. To the best of our knowledge, this is the highest CW output power at 946 nm generated by LD end-pumped Nd:YAG lasers. By using intracavity frequency doubling with an LBO crystal, we further obtained a 473-nm blue laser with an output power of 1.2 W, achieving an optical-to-optical conversion efficiency of 7.1% at a pump power of 16.9 W. The short-term power instability of the blue laser was less than 1 %.