Commercial red wines (Vitis vinifera L. cv. Shiraz) produced during the 2009 vintage underwent winemaker assessment for allocation grade soon after production. The wines were then subjected to ...phenolic analysis to measure wine color (total anthocyanin, SO2 nonbleachable pigment, and wine color density) and tannins (concentration, composition, and average degree of polymerization). A positive relationship was found between wine phenolic concentration and projected bottle price. Tannin compositional analysis suggested that there was specifically a relationship between wine grade and skin-derived tannins. These results suggest that maximization of skin tannin concentration and/or proportion is related to an increase in projected wine bottle price.
Multiple microsecond-length molecular dynamics simulations of complexes of Al(III) with amyloid-β (Aβ) peptides of varying length are reported, employing a non-bonded model of Al-coordination to the ...peptide, which is modelled using the AMBER ff14SB forcefield. Individual simulations reach equilibrium within 100 to 400 ns, as determined by root mean square deviations, leading to between 2.1 and 2.7 μs of equilibrated data. These reveal a compact set of configurations, with radius of gyration similar to that of the metal free peptide but larger than complexes with Cu, Fe and Zn. Strong coordination through acidic residues Glu3, Asp7 and Glu11 is maintained throughout all trajectories, leading to average coordination numbers of approximately 4 to 5. Helical conformations predominate, particularly in the longer Al-Aβ40 and Al-Aβ42 peptides, while β-strand forms are rare. Binding of the small, highly charged Al(III) ion to acidic residues in the N-terminus strongly disrupts their ability to engage in salt bridges, whereas residues outside the metal binding region engage in salt bridges to similar extent to the metal-free peptide, including the Asp23-Lys28 bridge known to be important for formation of fibrils. High helical content and disruption of salt bridges leads to characteristic tertiary structure, as shown by heat maps of contact between residues as well as representative clusters of trajectories.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Accumulation and compositional changes of flavonols, proanthocyanidins, and anthocyanins were measured in Vitis vinifera L. cv. Pinot noir in shaded and exposed treatments. In addition, extraction of ...these compounds into a model wine solution was measured. The study was conducted in a commercial vineyard within a uniform zone of relatively low vigor vines. Light exclusion boxes were installed on pairs of clusters on the same shoot (shaded treatment), and a second set of clusters on an adjacent shoot were labeled as the exposed treatment. Fruit samples were harvested at the onset of ripening (véraison) and at commercial harvest. Cluster shading resulted in a substantial decrease in mg/berry accumulation of flavonols and skin proanthocyanidins and minimal differences in anthocyanins. In analyzing seed proanthocyanidins by phloroglucinolysis, shaded and exposed treatments were similar at véraison; however, by harvest, the shaded treatment had higher extension and terminal subunits (nmol/seed) as compared to the exposed treatment. For skin proanthocyanidins, shaded fruit was lower for all subunits (nmol/berry) at both véraison and harvest. Shading caused an increase in the proportion of (−)-epicatechin and a decrease in (−)-epigallocatechin at harvest in skin extension subunits. Seed proanthocyanidins in shaded fruit contained a lower proportion of (+)-catechin and a higher proportion of (−)-epicatechin-3-O-gallate in extension subunits and a lower proportion of (+)-catechin and (−)-epicatechin-3-O-gallate and a higher proportion of (−)-epicatechin in terminal subunits. For anthocyanins, the shaded treatment had a proportional reduction in delphinidin, cyanidin, petunidin, and malvidin and a large increase in peonidin glucosides. The model extractions from the two treatments paralleled differences in the fruit with a lower concentration of flavonols, anthocyanins, and proanthocyanidins in the shaded treatment. The skin proanthocyanidin percent extraction was found to be ∼17% higher in the exposed model extraction than the shaded treatment. Keywords: Shading; UV exposure; flavonoids; flavonols; anthocyanins; proanthocyanidins; flavan-3ol monomers; HPLC; GPC; model wine extraction
Insoluble cell wall material was prepared from the skin and flesh of commercially ripe Vitis vinifera L. cv. Shiraz berries and then combined in suspension with preveraison skin and seed ...proanthocyanidin containing solutions. Analysis of proanthocyanidins before and after fining with cell wall material by phloroglucinolysis provided information on recovery by mass, subunit composition, and mean degree of polymerization, whereas proanthocyanidin molecular mass distribution was determined by gel permeation chromatography. Cell wall material from flesh showed the highest affinity for proanthocyanidin, binding up to 47% and 57% w/w of total seed and skin proanthocyanidin respectively. Comparison of the molecular mass distribution of skin or seed proanthocyanidin before and after fining indicated that affinity of cell walls for proanthocyanidin increased with increasing proanthocyanidin molecular mass. Initial results of subunit composition of skin and seed proanthocyanidin mixtures following fining with cell wall material showed that the % galloylation decreased, suggesting a preference for seed-derived proanthocyanidins. Subsequent experiments suggest that fining with insoluble cell wall material is size-based and does not have a specific affinity for seed-derived proanthocyanidins.
Refractoriness to induction chemotherapy and relapse after achievement of remission are the main obstacles to cure in acute myeloid leukaemia (AML). After standard induction chemotherapy, patients ...are assigned to different post-remission strategies on the basis of cytogenetic and molecular abnormalities that broadly define adverse, intermediate and favourable risk categories. However, some patients do not respond to induction therapy and another subset will eventually relapse despite the lack of adverse risk factors. There is an urgent need for better biomarkers to identify these high-risk patients before starting induction chemotherapy, to enable testing of alternative induction strategies in clinical trials. The high rate of relapse in AML has been attributed to the persistence of leukaemia stem cells (LSCs), which possess a number of stem cell properties, including quiescence, that are linked to therapy resistance. Here, to develop predictive and/or prognostic biomarkers related to stemness, we generated a list of genes that are differentially expressed between 138 LSC
and 89 LSC
cell fractions from 78 AML patients validated by xenotransplantation. To extract the core transcriptional components of stemness relevant to clinical outcomes, we performed sparse regression analysis of LSC gene expression against survival in a large training cohort, generating a 17-gene LSC score (LSC17). The LSC17 score was highly prognostic in five independent cohorts comprising patients of diverse AML subtypes (n = 908) and contributed greatly to accurate prediction of initial therapy resistance. Patients with high LSC17 scores had poor outcomes with current treatments including allogeneic stem cell transplantation. The LSC17 score provides clinicians with a rapid and powerful tool to identify AML patients who do not benefit from standard therapy and who should be enrolled in trials evaluating novel upfront or post-remission strategies.
The acetone-extractable (70% v/v) skin tannin content of Vitis vinifera L. cv. Cabernet Sauvignon grapes was found to increase during late-stage ripening. Conversely, skin tannin content determined ...following ethanol extraction (10, 20, and 50% v/v) did not consistently reflect this trend. The results indicated that a fraction of tannin became less extractable in aqueous ethanol during ripening. Skin cell walls were observed to become more porous during ripening, which may facilitate the sequestering of tannin as an adsorbed fraction within cell walls. For ethanol extracts, tannin molecular mass increased with advancing ripeness, even when extractable tannin content was constant, but this effect was negligible in acetone extracts. Reconstitution experiments with isolated skin tannin and cell wall material indicated that the selectivity of tannin adsorption by cell walls changed as tannin concentration increased. Tannin concentration, tannin molecular mass, and cell wall porosity are discussed as factors that may influence skin tannin extractability.
PDF
