In the context of dairy cow feeding, it is increasingly important to know the quality of the maize silage used in the ration and therefore, it appears to be crucial optimizing the techniques necessary to assess it. The aim of this study was to evaluate whether the Flieg-Zimmer's score (FZS), could properly estimate the quality of fermentations of maize silage made in a lab-scale ensiling system, and to calculate and validate new quality indexes suitable for lab-scale fermentations. The experimental dataset was obtained by analysing through near-infrared spectroscopy 522 samples of whole maize crop ensiled immediately after the harvest, using the vacuum-packing technique. The five (I1-I5) new indexes were calculated on the basis of seven parameters chosen among pH, lactic, acetic, propionic and butyric acids, ethanol, mannitol and ammonia. All the indexes were tested for normality with the Shapiro-Wilk test. In order to define the accuracy with which the new indexes ranked the maize silage on the basis of its fermentation quality, a ROC analysis was performed, using the FZS as gold standard test and dichotomizing the FZS in two levels according to a cutoff (FZS < 2 80, non-excellent vs. FZS ≥ 80, excellent). Accuracy was determined through the value of the area under the curve (AUC). Finally, a one-way ANOVA model was used to compare the quality of maize silage with low (< 320 g/kg), medium (320-360 g/kg) and high (> 360 g/kg) dry matter (DM). In the lab-scale silages the new indexes were normally distributed, whereas the FZS was not. The new indexes showed values of AUC ranging between 0.78 and 0.89, with the I5 index showing the best combination of sensitivity (0.87) and specificity (0.77) in discriminating between good and poor quality silage. The cutoff of the new indexes ranged between 45.5 and 57.4 points. The lab-scale silages were all excellent, no matter the category of DM. However, while the FZS did not differ among the 3 categories (mean FZS = 98.7), all the other indexes were significantly higher in silages with low DM (P < 0.001). Silages with low DM had the highest concentrations of lactic acid (56.4 g/kg DM, P < 0.001), ammonia (61.4 g/kg DM, P < 0.001) and butyric acid (0.62 g/kg DM, P < 0.001) as well. Data confirmed that the new proposed indexes are promising in describing the fermentation quality of maize silage in both field and lab-scale conditions.
The aim of this study was to assess the effects of earliness (according to FAO class), maturity stage at harvest and environmental conditions on the ensilability of maize hybrids described by their fermentation products and by a fermentation quality index (FQI). Maize hybrids belonging to early (n = 14) and late (n = 15) FAO classes were grown in low, medium and high potential yield areas and harvested at an early (EH), medium (MH) and late maturity stage (LH), that is, at 1/3, 2/3 and 5 d after the 2/3 milk line stage, respectively, according to a split‐plot design. Upon harvest, each sample (n = 522) was analysed for dry matter (DM) and water‐soluble carbohydrates (WSC) before being ensiled in vacuum‐packed bags (n = 1,044). After 60 days of conservation, samples were analysed for DM and fermentation products. In the pre‐ensiling phase, DM was higher in early hybrids (p = .001), low yield areas (p < .001) and at LH maturity (p < .001), whereas WSC contents were higher in early hybrids (p < .001), medium yield areas (p < .001) and at EH maturity (p < .001). With regard to silages, early hybrids had a higher FQI (p < .001), which was highest in areas with a high yield potential (p < .01) and at EH maturity (p < .01). Late hybrids proved to be better suited for low yield areas compared with early hybrids (p < .01) and had a higher FQI at EH and MH than at LH maturity (p < .01).
α-Synuclein forms amyloid deposits in the dopaminergic neurons; a process that is believed to contribute to the Parkinson's disease. An emerging theme in amyloid research is the hypothesis that the toxic species produced during amyloid formation share common physic-chemical features and exert their effects by common modes. This prompted the idea that molecules able to inhibit a protein aggregation process may cross-react with other amyloidogenic proteins, interfering in their fibrils formation. We investigate the ability of analogues of the heptapeptide H-Arg-Lys-Val-MePhe-Tyr-Thr-Trp- OH2, an inhibitor of Aβ-peptide aggregation, to cross-react with α-synuclein interfering with its fibril formation. The influence of the MePhe topography on the interaction with α-synuclein has also been evaluated, replacing the MePhe residue with either Phe or the conformationally restricted Tic residues. Peptides interact with good affinity with the α-synuclein monomer, promoting its aggregation process. This work provides the basis for the development of new drugs based on peptidomimetics able to modify the oligomers - mature fibrils equilibrium towards this last species.
The tyrosinase enzyme, which catalyzes the hydroxylation of monophenols and the oxidation of o-diphenols, is typically involved in the synthesis of the dark product melanin starting from the amino acid tyrosine. Contributing to the browning of plant and fruit tissues and to the hyperpigmentation of the skin, leading to melasma or age spots, the research of possible tyrosinase inhibitors has attracted much interest in agri-food, cosmetic, and medicinal industries. In this study, we analyzed the capability of antamanide, a mushroom bioactive cyclic decapeptide, and some of its glycine derivatives, compared to that of pseudostellarin A, a known tyrosinase inhibitor, to hinder tyrosinase activity by using a spectrophotometric method. Additionally, computational docking studies were performed in order to elucidate the interactions occurring with the tyrosinase catalytic site. Our results show that antamanide did not exert any inhibitory activity. On the contrary, the three glycine derivatives AG9, AG6, and AOG9, which differ from each other by the position of a glycine that substitutes phenylalanine in the parent molecule, improving water solubility and flexibility, showed tyrosinase inhibition by spectrophotometric assays. Analytical data were confirmed by computational studies.
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