Photodynamic and Antibacterial Assessment of Gold Nanoparticles Mediated by Gold (III) Chloride Trihydrate and Sodium Citrate under Alkaline Conditions.

Sodium citrate (SC) is sensitive to violet light illumination (VLI) and acts as a weak reductant. Conversely, gold (III) chloride trihydrate (GC) often acts as an oxidant in a redox reaction. In this study, the influences of colored light on the production of gold nanoparticles (AuNPs) in a mixture of gold (III) ions and citrate via VLI and the antibacterial photodynamic inactivation (aPDI) of Escherichia coli (E. coli) are determined under alkaline conditions. The diameter of AuNPs is within the range of 3-15 nm, i.e., their mean diameter is 9 nm; when citrate is mixed with gold (III) ions under VLI, AuNPs are formed via an electron transfer process. Additionally, GC mixed with SC (GCSC) inhibits E. coli more effectively under VLI than it does under blue, green, or red light. GCSC and SC are shown to inhibit E. coli populations by 4.67 and 1.12 logs, respectively, via VLI at 10 W/m2 for 60 min under alkaline conditions. GCSC-treated E. coli has a more significant photolytic effect on anionic superoxide radical (O2•-) formation under VLI, as more O2•- is formed within E. coli if the GCSC-treated samples are subjected to VLI. The O2•- exhibits a greater effect in a solution of GCSC than that shown by SC alone under VLI treatment. Gold (III) ions in a GCSC system appear to act as an oxidant by facilitating the electron transfer from citrate under VLI and the formation of AuNPs and O2•- via GCSC photolysis under alkaline conditions. As such, the photolysis of GCSC under VLI is a useful process that can be applied to aPDI.

Investigation of aluminum content of imported candies and snack foods in Taiwan.

Candies, chewing gums, dried fruits, jellies, chocolate, and shredded squid pieces imported from 17 countries were surveyed for their aluminum content. The samples were bought from candy shops, supermarkets, and convenience stores, and through online shopping. Sample selection focused on imported candies and snacks. A total of 67 samples, including five chewing gums, seven dried fruits, 13 chocolates, two jellies, two dried squid pieces, and 38 candies, were analyzed. The content of aluminum was analyzed by inductively coupled plasma optical emission spectrometry (ICP OES). The limit of quantitation for aluminum was 1.53 mg/kg. The content of aluminum ranged from not detected (ND) to 828.9 mg/kg. The mean concentrations of aluminum in chewing gums, dried fruits, chocolate, jellies, dried squid pieces, and candies were 36.62 mg/kg, 300.06 mg/kg, 9.1 mg/kg, 2.3 mg/kg, 7.8 mg/kg, and 24.26 mg/kg, respectively. Some samples had relatively high aluminum content. The highest aluminum content of 828.9 mg/kg was found in dried papaya threads imported from Thailand. Candies imported from Thailand and Vietnam had aluminum contents of 265.7 mg/kg and 333.1 mg/kg, respectively. Exposure risk assessment based on data from the Taiwan National Food Consumption Database was employed to calculate the percent provisional tolerable weekly intake (%PTWI). The percent provisional tolerable weekly intake of aluminum for adults (19-50 years) and children (3-6 years) based on the consumption rate of the total population showed that candies and snacks did not contribute greatly to aluminum exposure. By contrast, in the exposure assessment based on the consumers-only consumption rate, the estimated values of weekly exposure to aluminum from dried papaya threads in adults (19-50 years) and children (3-6 years) were 4.18 mg/kg body weight (bw)/wk and 7.93 mg/kg bw/wk, respectively, for 50th percentile consumers, and 6.26 mg/kg bw/wk and 12.88 mg/kg bw/wk, respectively, for 95th percentile consumers.

Comparative phosphoproteomic analysis of microsomal fractions of Arabidopsis thaliana and Oryza sativa subjected to high salinity.

Plants respond to salt stress by initiating phosphorylation cascades in their cells. Many key phosphorylation events take place at membranes. Microsomal fractions from 400 mM salt-treated Arabidopsis suspension plants were isolated, followed by trypsin shaving, enrichment using Zirconium ion-charged or TiO(2) magnetic beads, and tandem mass spectrometry analyses for site mapping. A total of 27 phosphorylation sites from 20 Arabidopsis proteins including photosystem II reaction center protein H PsbH were identified. In addition to Arabidopsis, microsomal fractions from shoots of 200 mM salt-treated rice was carried out, followed by trypsin digestion using shaving or tube-gel, and enrichment using Zirconium ion-charged or TiO(2) magnetic beads. This yielded identification of 13 phosphorylation sites from 8 proteins including photosystem II reaction center protein H PsbH. Label-free quantitative analysis suggests that the phosphorylation sites of PsbH were regulated by salt stress in Arabidopsis and rice. Sequence alignment of PsbH phosphorylation sites indicates that Thr-2 and Thr-4 are evolutionarily conserved in plants. Four conserved phosphorylation motifs were predicted, and these suggest that a specific unknown kinase or phosphatase is involved in high-salt stress responses in plants.

Simple and specific dual-wavelength excitable dye staining for glycoprotein detection in polyacrylamide gels and its application in glycoproteomics.

In this study, a commercially available fluorescent dye, Lissamine rhodamine B sulfonyl hydrazine (LRSH), was designed to specifically stain the glycoproteins in polyacrylamide gels. Through the periodate/Schiff base mechanism, the fluorescent dye readily attaches to glycoproteins and the fluorescence can be simultaneously observed under either 305 nm or 532 nm excitation therefore, the dye-stained glycoproteins can be detected under a regular UV transilluminator or a more elegant laser-based gel scanner. The specificity and detection limit were examined using a standard protein mixture in polyacrylamide gels in this study. The application of this glycoprotein stain dye was further demonstrated using pregnancy urine samples. The fluorescent spots were further digested in gel and their identities confirmed through LC-MS/MS analysis and database searching. In addition, the N-glycosylation sites of LRSH-labeled uromodulin were readily mapped via in-gel PNGaseF deglycosylation and LC-MS/MS analysis, which indicated that this fluorescent dye labeling does not interfere with enzymatic deglycosylation. Hence, the application of this simple and specific dual-wavelength excitable dye staining in current glycoproteome research is promising.