A Tissue Homogenate Method To Prepare Gram-Scale Allium Thiosulfinates and Their Disulfide Conjugates with Cysteine and Glutathione

The health benefits of Allium vegetables are widely attributed to the enzyme-derived organosulfur compounds called thiosulfinates (TS). However, the lack of a suitable method to prepare TS in good yields has hampered the evaluation of their biological activities. This paper describe a simple enzymatic method using <i>Allium</i> tissue homogenates as a reaction system to prepare gram-scale TS, including those enriched in 1-propenyl groups, which are particularly difficult to obtain. This method is simple, easy to scale up, and requires no column purification step, making it suitable for practical large-scale production of <i>Allium</i> TS. The prepared TS were further utilized to prepare the disulfide conjugates with cysteine and glutathione (CySSR and GSSR, R = methyl, ethyl, propyl, 1-propenyl, and allyl), which are the presumptive metabolites of TS. Among all of the <i>Allium</i> CySSR and GSSR conjugates, the newly prepared glutathione conjugate with 1-propenyl TS, GSSPe, showed the most potent effect to induce quinone reductase (QR, a representative phase II enzyme) in murine hepatoma cells (Hepa 1c1c7) and inhibit nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated macrophage cells (RAW 264.7)

Factors influencing transformation frequency of <i>L. monocytogenes</i> 12443 electroporated with pNF8.

a<p>Details provided in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0018083#s2" target="_blank">Materials and Methods</a> section, W/E buffer is washing/electroporation buffer.</p>b<p>Transformation frequency was calculated as numbers of transformants per microgram of plasmid DNA and the values are means of two independent experiments.</p

Comparison of growth rates of GFP-labeled and parental bacterial strains.

<p>Growth rates of GFP-labeled (Δ) and parental (□) bacterial strains were determined by cell counts (A, B, C, D) and spectrophotometrically at OD₆₀₀ (a, b, c, d) for <i>E. coli</i> O157:H7 F4546 (A, a); <i>Salmonella</i> Enteritidis ME-18 (B, b); <i>Listeria innocua</i> E (C, c); and <i>Listeria monocytogenes</i> G3982 (D, d). Point values are the means of at least two trials.</p

Plasmid stability in GFP-labeled bacterial strains.

a<p>Plasmid loss was calculated as the ratio between the counts of green fluorescent colonies and total colony counts on nonselective plates.</p>b<p>Plasmid loss was ≥4 logs.</p

Bacterial strains and plasmids used in this study.

a<p>CDC, Centers for Disease Control and Prevention; FDA, Food and Drug Administration: CFS, Center for Food Safety, The University of Georgia; USDA, The United States Department of Agriculture.</p

Data_Sheet_1_Green physical activity for leisure connects perceived residential greenspace and mental well-being.docx

Physical activity serves as a pivotal mediator in previous theoretical frameworks that link greenspace and human health. However, it remains unclear whether the domain of physical activity within and around greenspaces can alter the pathway. The present study recruited 668 participants online and examined a conceptual framework that explores the associations between residential greenspace and mental well-being, with a particular focus on the mediation effect of green physical activity (physical activity undertaken in and around greenspaces). Moreover, socio-demographic characteristics, including gender, age, household income, education status, marital status, and student status, were controlled for during the examination. The investigated green physical activities included leisure activities, transportation walking, and transportation cycling, and they were measured by a pre-established questionnaire. Meanwhile, mental well-being was measured by the WHO-5 well-being index, and residential greenspace was indicated by self-reported perceived greenspace and mean Normalized Difference Vegetation Index (NDVI) values within 500 meters (m) of residential radius. We found that both perceived greenspace (B = 1.852, p 500 m (B = 3.230, p = 0.038) were positively associated with mental well-being. However, only perceived greenspace, not NDVI 500 m, exhibited positive associations with the three green physical activity items. Furthermore, only green physical activity for leisure (B = 0.223, p  0.05), mediated the relationship between perceived greenspace and mental well-being. Our findings reinforce previous studies on “greenspace-health” frameworks and underline the importance of leisure physical activity in promoting mental well-being.</p

Physical and Chemical Stability of Curcumin in Aqueous Solutions and Emulsions: Impact of pH, Temperature, and Molecular Environment

The utilization of curcumin as a nutraceutical in food and supplement products is often limited because of its low water solubility, poor chemical stability, and low oral bioavailability. This study examined the impact of pH, storage temperature, and molecular environment on the physical and chemical stability of pure curcumin in aqueous solutions and in oil-in-water emulsions. Unlike naturally occurring curcuminoid mixtures (that contain curcumin, demethoxy-curcumin, and bisdemethoxy-curcumin), pure curcumin was highly unstable to chemical degradation in alkaline aqueous solutions (pH ≥7.0) and tended to crystallize out of aqueous acidic solutions (pH <7). These effects were attributed to changes in the molecular structure of curcumin under different pH conditions. The curcumin crystals formed were relatively large (10–50 μm), which made them prone to rapid sedimentation. The incorporation of curcumin into oil-in-water emulsions (30% MCT, 1 mg curcumin/g MCT, <i>d</i>₃₂ ≈ 298 nm) improved its water dispersibility and chemical stability. After incubation at 37 °C for 1 month, >85% of curcumin was retained by emulsions stored under acidic conditions (pH <7), whereas 62, 60, and 53% was retained by emulsions stored at pH 7.0, 7.4, and 8.0, respectively. There was little change in the color of curcumin-loaded emulsions when stored under acidic conditions, but their yellow color faded when stored under alkaline conditions. There was no evidence of droplet aggregation or creaming in emulsions stored for 31 days at ambient temperature. These results suggest that emulsion-based delivery systems may be suitable for improving the water dispersibility and chemical stability of curcumin, which would facilitate its application in foods and supplements

Late-Stage Diversification of Peptides via Pd-Catalyzed Site-Selective δ‑C(sp²)‑H Fluorination and Amination

Site-selective C–H fluorination is an attractive strategy for directly transforming inert C–H bonds into C–F bonds, yet it remains a significant challenge. Herein, we have developed an efficient and versatile strategy for site-selective fluorination and amination of phenylalanine-containing peptides via late-stage Pd-catalyzed δ-C(sp2)-H activation, providing a valuable tool for the in situ synthesis of fluorinated indoline scaffolds within peptides

A Reaction Mechanism of Methane Coupling on a Silica-Supported Single-Site Tantalum Catalyst

Density functional theory calculations were utilized to study the reaction mechanisms of nonoxidative coupling of methane (NOCM) occurring on a silica-supported single-site tantalum (Ta) catalyst. Two catalytic cycles, namely, catalytic cycles A (CCA) and B (CCB), as well as other competing pathways, were investigated by exploring the potential energy surfaces for the reactions of interest. The supported methyltantalum [(SiO₃)₂Ta–CH₃] and tantalum hydride [(SiO₃)₂Ta–H] catalyzed the reaction of NOCM through CCA and CCB, respectively. CCA and CCB comprise five and six elementary steps, respectively. The two rate-determining states for both catalytic cycles were elucidated. The turnover number of methane conversion catalyzed by the supported methyltantalum was about 10⁵ larger than that catalyzed by the supported tantalum hydride. This large difference indicates that the former species is predominantly responsible for the conversion of methane to ethane

Salt-Induced Assembly Transformation of DNA–AuNP Conjugates Based on RCA Origami: From Linear Arrays to Nanorings

We developed a simple method to adjust the structural transformation of DNA–gold nanoparticles assemblies from linear arrays to nanorings by increasing salt concentrations. A DNA nanoladder constructing from RCA origami acted as templates to assemble periodic AuNPs arrays by a terminal thiol located on staple oligonucleotides. The linear AuNPs arrays could be transformed into nanorings only by changing the concentration of NaCl aqueous solution during the assembly process. It was proven that the electrostatic repulsion, being asymmetrically diminished by the high concentration of NaCl, caused the formation of nanoring architectures