Anthocyanin and Phenolic Acids Contents Influence the Color Stability and Antioxidant Capacity of Wine Treated With Mannoprotein.

Wine is consumed by humans worldwide, but the functional components are lost and the color changes during its production. Here, we studied the effects of mannoprotein (MP) addition (0, 0.1, and 0.3 g/L) upon crushing and storage. We measured anthocyanins, phenolic acids profiles, color characteristics, and antioxidant activities of wine. The results showed that the addition of MP before fermentation significantly increased the total phenolic content (TPC), total anthocyanin content, total tannin content (TTC), total flavonoid content, and total flavanol content in wine, whereas the addition of MP during storage had the opposite effect. The addition of MP before alcohol fermentation significantly increased the amount of individual anthocyanins and individual phenolic acids, maintained the color, and increased the antioxidant capacity of wine. In addition, the addition of 0.3 g/L MP during storage increased the content of individual phenolic acids and TPC of wine. However, the addition of 0.1 g/L MP during storage significantly reduced the TPC, TAC, TTC, and individual anthocyanin content (except for malvidin-3-glucoside and malvidin-3-acetly-glucoside); meanwhile, the treatment attenuated the color stability and antioxidant capacity of wine. The results demonstrated that the addition of MP before alcohol fermentation could increase the functional components and improve the color stability and antioxidant capacity of wine.

The condensed tannin chemistry and astringency properties of fifteen Vitis davidii Foex grapes and wines.

This study sought to determine the effects of variety on the astringency and chemistry of condensed tannins of spine grapes and wines. Fifteen varieties of red spine grape (Vitis davidii Foex) were used. Condensed tannin content, composition, and wine astringency were determined. The condensed tannin profiles were assessed by high-performance liquid chromatography coupled with diode array detector (HPLC-DAD). The condensed tannin content highly depended on the variety ranging from 0.30 mg/g to 7.80 mg/g (in skins), from 3.12 mg/g to 8.82 mg/g (in seeds), and from 62.60 mg/L to 225.90 mg/L (in wines). There were significant differences in proportions of certain constitutive subunits (as mole%) and mean degree of polymerization (mDp) among the varieties. Correlation analysis revealed that condensed tannin concentration and composition had a significant effect on the sensory evaluation and quantitative analysis of astringency. A positive correlation between mDp and astringency was also observed. The present results expand knowledge of the characterization of spine grape and wine condensed tannin chemistry and astringency.

The near-infrared dye IR-61 restores erectile function in a streptozotocin-induced diabetes model via mitochondrial protection.

This study aimed to evaluate the therapeutic effect of IR-61, a novel mitochondrial heptamethine cyanine dye with antioxidant effects, on diabetes mellitus-induced erectile dysfunction (DMED). Eight-week-old male Sprague-Dawley rats were intraperitoneally injected with streptozotocin (STZ) to induce type 1 diabetes. Eight weeks after STZ injection, all rats were divided into three groups: the control group, DM group, and DM + IR-61 group. In the DM + IR-61 group, the rats were administered IR-61 (1.6 mg kg-1) twice a week by intravenous injection. At week 13, erectile function was evaluated by determining the ratio of the maximal intracavernous pressure to mean arterial pressure, and the penises were then harvested for fluorescent imaging, transmission electron microscopy, histological examinations, and Western blot analysis. Whole-body imaging suggested that IR-61 was highly accumulated in the penis after intravenous injection. IR-61 treatment significantly improved the maximal ICP of diabetic rats. Additionally, IR-61 ameliorated diabetes-induced inflammation, apoptosis, and phenotypic transition of corpus cavernosum smooth muscle cells (CCSMCs) in penile tissue. IR-61 also attenuated mitochondrial damage, reduced reactive oxygen species production in the corpus cavernosum and upregulated sirtuin1 (SIRT1), sirtuin3 (SIRT3), nuclear factor (erythroid-derived 2)-like 2 (Nrf2), and heme oxygenase expression in penile tissue. In conclusion, IR-61 represents a potential therapeutic option for DMED by protecting the mitochondria of CCSMCs, which may be mediated by activation of the SIRT1, SIRT3, and Nrf2 pathways.

Targeted Metabolomic and Transcript Level Analysis Reveals Quality Characteristic of Chinese Wild Grapes (Vitis davidii Foex).

Native to China, spine grapes (Vitis davidii Foex) are an important wild grape species. Here, the quality characteristics of one white and three red spine grape clones were evaluated via targeted metabolomic and transcription level analysis. Xiangzhenzhu (XZZ) had the highest soluble sugar and organic acid content. Malvidin-3-acetyl-glucoside and cyanidin-3-glucoside were the characteristic anthocyanins in spine grapes, and significant differences in anthocyanin composition between different clones were detected. Anthocyanins were not detected in Baiyu (BY) grapes. The transcript levels of VdGST, VdF3'H, VdOMT, VdLDOX, and VdUFGT were significantly related to the anthocyanin biosynthesis and proportions. A total of 27 kinds of glycosidically bound volatiles (including alcohols, monoterpenes, esters, aldehydes, ketones, and phenolic acid) were identified in spine grapes, with Gaoshan #4 (G4) and BY grapes having the highest concentrations. The VdGT expression levels were closely related to glycosidically bound volatile concentrations. These results increase our understanding of the quality of wild spine grapes and further promote the development and use of wild grape resources.

Overexpression of grapevine VvNAC08 enhances drought tolerance in transgenic Arabidopsis.

NAC [No apical meristem (NAM), Arabidopsis transcription activation factor (ATAF), Cup-shaped cotyledon (CUC)] transcription factors (TFs) play an important role in plant growth and response to various environmental stress. Drought stress is the primary factor limiting the growth and fruit quality of grapevines worldwide. However, the biological function of the NAC family members in grapevine is not clear. In this study, we reported that VvNAC08, a novel NAC transcription factor gene, was expressed after drought, salicylic acid (SA) and abscisic acid (ABA), jasmonic acid (JA) and melatonin (MT) treatments in grapevine. VvNAC08 was expressed in various tissues. The open reading frame (ORF) of VvNAC08 was 792 bp, encoding 263 amino acids. The VvNAC08 protein could bind to NACRS [CGTA/CACG] in yeast. When subjected to drought and dehydration stress, VvNAC08-overexpression (OE) Arabidopsis had a higher survival rate and a lower water loss rate than wild type (WT) plants. Under drought conditions, transgenic Arabidopsis overexpressing VvNAC08 had a lower malondialdehyde (MDA), H2O2 contents, but a higher peroxidase (POD), superoxide dismutase (SOD) and catalase (CAT) activities as well as more proline content. Moreover, the expressions of marker genes, including ABI5, AREB1, COR15A, COR47, P5CS, RD22, and RD29A, were up-regulated in VvNAC08-overexpression lines when subjected to drought treatments. The results suggest that the transgenic Arabidopsis overexpressing VvNAC08 enhances resistance to drought while up-regulating the expressions of ABA- and stress-related genes.

VvNAC17, a novel stress-responsive grapevine (Vitis vinifera L.) NAC transcription factor, increases sensitivity to abscisic acid and enhances salinity, freezing, and drought tolerance in transgenic Arabidopsis.

Drought stress is the primary factor limiting the growth and fruit quality of grapevines worldwide. However, the biological function of the NAC [No apical meristem (NAM), Arabidopsis transcription activation factor (ATAF), Cup-shaped cotyledon (CUC)] transcription factor (TF) in grapevine is not clear. In this study, we reported that VvNAC17, a novel NAC transcription factor, was expressed in various tissues following drought, high temperature (45 °C), freezing (4 °C), salicylic acid (SA), and abscisic acid (ABA) treatments in grapevine. The VvNAC17 protein was localized in the nucleus of Arabidopsis thaliana protoplasts and demonstrated transcriptional activation activities at its C-terminus in yeast. The VvNAC17 gene was overexpressed in Arabidopsis thaliana. Under mannitol and salt stress, the germination rates of the VvNAC17-overexpression lines were higher than those of the wild-type plants, as were the root lengths. The VvNAC17-overexpression lines showed greater tolerance to freezing stress along with a higher survival rate. Following ABA treatment, the seed germination rate and the root length of the VvNAC17-overexpression lines were inhibited, and the stomatal opening and stomatal density were reduced. When subjected to drought and dehydration stress, the VvNAC17-overexpression lines showed improved survival and reduced water loss rates in comparison to the wild-type plants. Under drought conditions, the VvNAC17-overexpression lines had lower malondialdehyde and H2O2 contents, but higher peroxidase, superoxide dismutase, and catalase activities as well as higher proline content. Moreover, the expression of marker genes, including ABI5, AREB1, COR15A, COR47, P5CS, RD22, and RD29A, was up-regulated in the VvNAC17-overexpression lines when subjected to ABA and drought treatments. The results suggest that in transgenic Arabidopsis over-expression of VvNAC17 enhances resistance to drought while up-regulating the expression of ABA- and stress-related genes.

Physiological, micro-morphological and metabolomic analysis of grapevine (Vitis vinifera L.) leaf of plants under water stress.

Grapes are one of the most important fruits because of their economic and nutritional benefits, and grapevines are widely cultivated in arid and semi-arid areas. Therefore, it is critical to study the mechanism by which grapevines respond to water stress. In this research, micro-morphological and metabolomic analyses were conducted to evaluate the effects of water stress on stomatal morphology and volatile compounds extracted from the leaves of grapevine plants. There were two treatments: well-watered plants (watered daily) and drought-stressed plants (no irrigation). Plant weights were recorded, and the well-watered plants were irrigated daily to replace the water lost to evapotranspiration. The water status of the grapevines was determined according to their relative water content. The changes in proline content, hydrogen peroxide content, lipid peroxidation and antioxidant activities, as well as those of photosynthetic parameters and chlorophyll fluorescence, were monitored as markers of water stress. The microscopic changes in stomatal behavior were observed using a scanning electron microscope. A total of 12 secondary volatile compounds, including aldehydes, ketones and alcohols, were detected in the grapevine leaves. Among them, (E)-2-hexenal and 3-hexenal showed a significant increase after water stress. Multivariate statistical analysis revealed that the levels of 3-hexenal and (E)-2-hexenal were closely related to the changes in proline, hydrogen peroxide (H2O2), malondialdehyde (MDA), catalase (CAT) and superoxide dismutase (SOD). These results suggested that water stress could regulate the accumulation of green leaf volatiles, especially (E)-2-hexenal and 3-hexenal, in coordination with the reactive oxygen species (ROS) scavenging system. These compounds may act as signaling compounds in response to water stress in grapevines.

Effects of Regulated Deficit Irrigation on Amino Acid Profiles and Their Derived Volatile Compounds in Cabernet Sauvignon (Vitis vinifera L.) Grapes and Wines.

Amino acid contents and their derived volatile compositions in Cabernet Sauvignon grapes and wines after regulated deficit irrigation (RDI) were investigated during the 2015 and 2016 growing seasons in Yinchuan (NingXia, China). High-performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS) were used for amino acid and volatile compound analyses. Three RDI strategies were tested: 60% (RDI-1), 70% (RDI-2), and 80% (RDI-3) of grapevine estimated evapotranspiration (ETc), and 100% ETc was used as the control group (CK). RDI-treated vines had lower yields and berry weights with higher total soluble solids than the control treatment. RDI-1 increased proline levels in berries and wines. RDI-2 enhanced tyrosine and asparagine levels in wines. RDI-3 enhanced arginine, alanine, valine, leucine, and isoleucine levels in berries and wines. RDI-2 and RDI-3 increased the concentrations of 2-methyl-1-butyl acetate, benzaldehyde, 3-methyl-1-pentanol, and 3-methyl-1-butanol in wines. The accumulation of volatile compounds was closely related to the amino acid concentrations-especially isoleucine, valine, and leucine-in grapes. Our results showed that RDI treatments altered amino acid concentrations and their derived volatile compositions in wines.

Effect of regulated deficit irrigation on fatty acids and their derived volatiles in 'Cabernet Sauvignon' grapes and wines of Ningxia, China.

The effect of regulated deficit irrigation (RDI) on fatty acids and their derived volatiles in 'Cabernet Sauvignon' grapes and wines was investigated during two growing seasons in the east foot of Mt. Helan, the semi-arid area. The vines received water with 60% (RDI-1), 70% (RDI-2), 80% (RDI-3), 100% (CK, traditional drip irrigation) of their estimated evapotranspiration (ETc) respectively. RDI treatments resulted in lower yield, berry weight and titratable acidity with higher total soluble solids. RDI-1 increased the content of unsaturated fatty acids in berries and decreased the level of alcohols and esters volatiles in wines. RDI-2 and RDI-3 enhanced 1-hexanol and esters in wines in comparison with CK. The concentrations of C6 aroma compounds were closely correlated with unsaturated fatty acids (p < .05), especially linolenic acid and linoleic acid. The present results provided direct evidence and detailed data to explain the effect of RDI on grapes and wines composition regarding fatty acids and their derived volatiles.

Study for relevance of the acute myocardial ischemia to arrhythmia by the optical mapping method.

Ventricular arrhythmias are commonly observed in patients with acute coronary occlusion and ischemia. The purpose of the present study is to determine ischemic electrophysiological effects and their role in ischemia-induced arrhythmia. Optical mapping of the membrane potential with voltage-sensitive dyes was used in the study. The mapping was performed with di-4-ANEPPS in Langendorff-perfused rabbit hearts. The excitation-contraction decoupler 2,3-butanedione monoxime was used to suppress motion artifacts caused by contraction of the heart. The acute global ischemia was developed by a rapid reduction of the flow rate. The experiments revealed that ischemic tissues were characterized by an obvious reduction in action potential duration and action potential upstroke, slower conduction velocity (CV) and the property of post-repolarization refractoriness. Moreover, the magnitude of CV reduced both in control and ischemia when the pacing cycle length was short. CV reduction was even early in ischemia, resulting in a broader curve during ischemia. Moreover, the dominant frequency of ventricular tachycardia/ventricular fibrillation (VT/VF) in ischemia was less than that in control, implying a decreasing tendency of VT/VF frequency for low excitability. Therefore, combined with our previous simulation study, the dynamic changes of CV and longer refractory period were suggested to play an important role in the ischemia-related arrhythmia. Low excitability in ischemic tissue was the fundamental mechanism in it.