213 research outputs found
Bioactive Peptides from Angelica sinensis
Since excessive reactive oxygen species (ROS) is known to be associated with aging and age-related diseases, strategies modulating ROS level and antioxidant defense systems may contribute to the delay of senescence. Here we show that the protein hydrolyzate from Angelica sinensis was capable of increasing oxidative survival of the model animal Caenorhabditis elegans intoxicated by paraquat. The hydrolyzate was then fractionated by ultrafiltration, and the antioxidant fraction (<3 kDa) was purified by gel filtration to obtain the antioxidant A. sinensis peptides (AsiPeps), which were mostly composed of peptides with <20 amino acid residues. Further studies demonstrate that AsiPeps were able to reduce the endogenous ROS level, increase the activities of the antioxidant enzymes superoxide dismutase and catalase, and decrease the content of the lipid peroxidation product malondialdehyde in nematodes treated with paraquat or undergoing senescence. AsiPeps were also shown to reduce age pigments accumulation and extend lifespan but did not affect the food-intake behavior of the nematodes. Taken together, our results demonstrate that A. sinensis peptides (AsiPeps) are able to delay aging process in C. elegans through antioxidant activities independent of dietary restriction
Berry composition and wine quality of Pinot noir as affected by leaf area to crop load ratio
The effect of vine leaf area (LA) relative to crop load (CL) was investigated in the cool climate growing region of Canterbury, New Zealand, using Pinot noir (clone 10/5) Vertical Shoot Positioning (VSP) trained vines. Three weeks after fruit-set, vine leaf numbers were standardized with two of the four basal leaves retained in all cases. LA treatments were 12 leaves (1L), 6 leaves (0.5L) or 3 leaves (0.25L) per shoot. CL treatments were full crop (1C), half crop (0.5C) or quarter crop (0.25C) by removing equal numbers of primary and secondary clusters, producing five different treatment ratios (TMR), “0.25”, “0.5”, “1”, “2” and “4”. Treatments were applied in a 4-replicate split plot design. Grapes were harvested on April 4, 2014 and replicates 1 & 4 and 2 & 3 were combined to make two wines from each treatment. LA/CL (cm²/g) was estimated from a subsample of shoot leaf areas divided by total yield per vine after harvest.
Starch dry weight in roots was not affected by crop load, but was decreased with leaf removal, while pruning weight was increased with increasing TMR, indicating that the fruiting capacity for next season could be reduced by limited leaf numbers.
Juice °Brix was negatively, while juice pH was positively, related with increasing levels of leaf removal. Total red pigments, tannin concentration and total phenolics in skin extracts were decreased by greater leaf removal (p < 0.05, p < 0.01 and p < 0.05, respectively). Results suggest shading appeared not to be a limiting factor for the synthesis of phenolic compounds, or to have an impact on fruit composition in general (i.e. potassium, malic or tartaric acids).
The concentration of total red pigments, tannin and total phenolics in wine were not significantly different between treatments, though some visual differences were observed using the CIELab method on native wine samples. HPLC analysis of wine showed that two procyanidins dimers, rutin, caffeic acid and caftaric acid were affected by crop removal only, while quercetin, quercetin-glucuronoide 1 and protocatechuic acid were affected by leaf removal only. Kaempferol-glucoside, p-hydroxybenzoic acid and p-coumaric acid were affected by both leaf removal and crop removal treatments. GCMS analysis showed the concentrations of fatty acids and some esters were higher when more leaves and more crop were retained, and that the concentrations of C6 alcohols were positively related with TMR.
Some wine parameters showed the same patterns as that found for grapes, including pH, colour hue, degree of red pigment colouration, and kaempferol-glucoside concentration, along with the CIELab visual colour pattern. Thus, the fruit characteristics can be transferred into wine.
It appears that the most appropriate LA/CL or TMR to produce quality wines were not the extreme values (e.g. the highest or lowest LA/CL, or TMR =“0.25” or “4”) based on the chemical analysis in this study. In fact, lower to medium levels of leaf and crop removal were desired, based on the concentrations of phenolics, volatile aroma compounds, carbohydrate in grapevine roots, along with other parameters measured in this project
Sidechain Metallopolymers with Precisely Controlled Structures: Synthesis and Application in Catalysis
Inspired by the cooperative multi-metallic activation in metalloenzyme catalysis, artificial enzymes as multi-metallic catalysts have been developed for improved kinetics and higher selectivity. Previous models about multi-metallic catalysts, such as cross-linked polymer-supported catalysts, failed to precisely control the number and location of their active sites, leading to low activity and selectivity. In recent years, metallopolymers with metals in the sidechain, also named as sidechain metallopolymers (SMPs), have attracted much attention because of their combination of the catalytic, magnetic, and electronic properties of metals with desirable mechanical and processing properties of polymeric backbones. Living and controlled polymerization techniques provide access to SMPs with precisely controlled structures, for example, controlled degree of polymerization (DP) and molecular weight dispersity (Đ), which may have excellent performance as multi-metallic catalysts in a variety of catalytic reactions. This review will cover the recent advances about SMPs, especially on their synthesis and application in catalysis. These tailor-made SMPs with metallic catalytic centers can precisely control the number and location of their active sites, exhibiting high catalytic efficiency
Analyses of cool climate Pinot noir vine and fruit parameters as affected by altered leaf area/crop load ratios
The effect of vine leaf area relative to crop load was investigated in the cool climate growing region of Canterbury New Zealand using Pinot noir (clone 10/5) VSP trained vines. Three weeks after fruit set shoot leaf numbers were standardised and leaf area (LA) adjusted to 100%, 50% or 25%. Crop load (CL) was similarly adjusted, with treatments applied in a 4-replicate split plot design. The resulting LA to CL ratios ranged from 4 to 69 on average. Grapes were harvested on April 4, 2014 and a suite of analysis applied so that Canonical Variate Analysis (CVA) and Principal Component Analysis (PCA) could be used to look for treatment influences. Of the parameters measured, the following were used in the CVA analysis: Root starch, Seed dry weight, Skin weight per berry, Juice ⁰Brix, Juice pH, Citric acid, Phosphorus, Total phenolics in skin extract per berry, Tannin in skin extract per berry, Colour hue, Degree of red pigment colouration, Malvin and Kaempferol-glucoside. CVA revealed distinct groupings with 25% leaf having higher Degree of pigment colouration, Colour hue, Kaempferol glucoside and lower values for Skin weight per berry, Root starch and Seed dry weight. PCA of a subset of these variates also showed groupings by leaf level, with 100% leaf leading to higher values for Tannin in skin extract per berry, Total phenolics in skin extract per berry, Malvin, Skin weight per berry and Root starch, whereas 25% leaf was weighted towards Kaempferol-glucoside and lesser amounts of the other factors. The results suggest that there was an influence of leaf removal on fruit exposure, leading to higher flavonol concentration, but higher leaf area was responsible for greater berry skin weight, seed weight, various phenolics and stored carbohydrate. Very low LA:CL are not beneficial for fruit composition or vine health
Characterization of Bioactive Compounds in Lees from New Zealand Wines with Different Vinification Backgrounds
Wine lees are one of the main by-products produced during winemaking. Little is known about the effect of the vinification technique on the phenolic compounds and the biological activity of wine lees extracts. Wine lees collected at varying vinification sources of two grape varieties, Riesling (RL) and Pinot Noir (PN), were analyzed for total phenolic content (TPC), tannin content (TTC), their anthocyanin and phenolic profile, and the antioxidant and antimicrobial activities of their extracts. The results showed a low TPC and TTC in RL lees, which could be attributed to the varietal characteristic of RL grapes and to less skin contact during vinification. Vinification techniques modified the composition of the phenolic compounds in the lees. The results showed a good linear relationship between the antioxidant activities and the TPC and TTC, indicating that PN lees were better sources of phenolics and antioxidant activity than RL lees. The antimicrobial activity of wine lees was related to the phenolic composition rather than the quantity of total phenolics. Knowing the grape and wine processing conditions can provide some insights into the potential composition of wine lees and, hence, determine the potential economic use of the by-product
HIV prevalence among female sex workers in Guigang City, Guangxi, China: an 8-year consecutive cross-sectional study
Abstract Background Female sex workers (FSW) are a population that are at high risk for HIV infection, and their HIV/AIDS knowledge levels and sexual behaviors are of concern. This study describes changes in HIV prevalence and factors associated among female sex workers in Guigang City, Guangxi, one of the highest HIV prevalence areas in China. Methods Data were derived from an annual cross-sectional venue-based survey, 2008 to 2015, in the form of sentinel surveillance. The participants were recruited using cluster sampling. FSW aged 16 years and above who completed a questionnaire and HIV testing. Both descriptive and multi-level analyses were used to explore factors associated with changes in HIV prevalence. Results Seven thousand four hundred ninety-six FSW were recruited in this study. HIV prevalence among FSW in Guigang City fell into two periods, one with an increasing trend (2008–2011) and one with a decline (2012–2015). Differences between these time periods included age, relationship status, HIV knowledge, consistent condom use, lifetime illicit drug use, history of sexually transmitted infection in the past year, HIV testing, receipt of a condom distribution and education program or HIV counseling and testing, and peer education services. Conclusions Since 2012, a reduction in HIV prevalence among FSW in Guigang City has been observed. The decline of HIV prevalence was associated with coinciding changes in demographic characteristics of FSW, improvement of HIV knowledge and safer sexual behaviors, and a program that promotes condom use, HIV counseling & testing, and peer education
Effects of microencapsulated abamectin on the mechanical, cross-linking, and release properties of PBS
HIV prevalence among female sex workers in Guigang City, Guangxi, China: an 8-year consecutive cross-sectional study
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