Selected Schizosaccharomyces pombe Strains Have Characteristics That Are Beneficial for Winemaking

At present, wine is generally produced using Saccharomyces yeast followed by Oenococus bacteria to complete malolactic fermentation. This method has some unsolved problems, such as the management of highly acidic musts and the production of potentially toxic products including biogenic amines and ethyl carbamate. Here we explore the potential of the fission yeast Schizosaccharomyces pombe to solve these problems. We characterise an extensive worldwide collection of S. pombe strains according to classic biochemical parameters of oenological interest. We identify three genetically different S. pombe strains that appear suitable for winemaking. These strains compare favourably to standard Saccharomyces cerevisiae winemaking strains, in that they perform effective malic acid deacidification and significantly reduce levels of biogenic amines and ethyl carbamate precursors without the need for any secondary bacterial malolactic fermentation. These findings indicate that the use of certain S. pombe strains could be advantageous for winemaking in regions where malic acid is problematic, and these strains also show superior performance with respect to food safety

Potential of a multiparametric optical sensor for determining in situ the maturity components of red and white vitis vinifera wine grapes

A non-destructive fluorescence-based technique for evaluating Vitis vinifera L. grape maturity using a portable sensor (Multiplex ®) is presented. It provides indices of anthocyanins and chlorophyll in Cabernet Sauvignon, Merlot and Sangiovese red grapes and of flavonols and chlorophyll in Vermentino white grapes. The good exponential relationship between the anthocyanin index and the actual anthocyanin content determined by wet chemistry was used to estimate grape anthocyanins from in field sensor data during ripening. Marked differences were found in the kinetics and the amount of anthocyanins between cultivars and between seasons. A sensor-driven mapping of the anthocyanin content in the grapes, expressed as g/kg fresh weight, was performed on a 7-ha vineyard planted with Sangiovese. In the Vermentino, the flavonol index was favorably correlated to the actual content of berry skin flavonols determined by means of HPLC analysis of skin extracts. It was used to make a non-destructive estimate of the evolution in the flavonol concentration in grape berry samplings. The chlorophyll index was inversely correlated in linear manner to the total soluble solids (°Brix): it could, therefore, be used as a new index of technological maturity. The fluorescence sensor (Multiplex) possesses a high potential for representing an important innovative tool for controlling grape maturity in precision viticulture

Influence of skin contact and different extractants on extraction of proteins and phenolic substances in Sauvignon Blanc grape skin

Background and Aims: Although most proteins and a significant proportion of phenolic substances are extracted from grape pulp, the extraction of grape skin components may contribute to and modulate the final concentration of these components in juice. This study investigated the influence of skin contact time and various extractants on the extraction of Sauvignon Blanc grape skin components. Methods and Results: Two trials were conducted. The first evaluated the impact of skin contact time on the extraction of phenolic substances and proteins from grapes (fresh vs chilled) into juice. The juice with 24 h skin contact showed a significantly higher concentration of phenolic substances and chitinases, but not of thaumatin-like proteins. No difference was observed between fresh and chilled berries. The second trial evaluated the extractability of phenolic substances and proteins from grape skin (ground vs peeled) using different extractants. More phenolic substances and tannin were extracted using ground skin powder as greater mechanical damage assisted in the extraction of skin components. Compared to mechanically crushed and pressed grape juice, hand squeezed juice showed a lower protein concentration and the presence of tannin. It is suggested that hand squeezing was more effective in extracting components (mainly phenolic substances) from grape skin, but mechanically crushing and pressing was more effective in extracting components (mainly proteins) from grape pulp. Extractants containing bovine serum albumin or protein resulted in a lower concentration of phenolic substances and tannin in the extracts, and the concentration of bovine serum albumin and protein was dramatically decreased after extraction. Conclusion: This study confirmed that longer skin contact increased the extraction of skin phenolic substances. Longer skin contact also increased the protein concentration in juice, particularly the pathogenesis-related proteins, but it can be modulated by the co-extraction of phenolic substances. Significance of the Study: This study improves our current understanding of interactions between phenolics and proteins during grape processing, which can be used as a tool for winemakers to manage the extraction of these compounds into juice

Accumulation of cellular prion protein within β-amyloid oligomer plaques in aged human brains

Alzheimer's disease (AD) is the main cause of dementia, and β-amyloid (Aβ) is a central factor in the initiation and progression of the disease. Different forms of Aβ have been identified as monomers, oligomers, and amyloid fibrils. Many proteins have been implicated as putative receptors of respective forms of Aβ. Distinct forms of Aβ oligomers are considered to be neurotoxic species that trigger the pathophysiology of AD. It was reported that cellular prion protein (PrPC ) is one of the most selective and high-affinity binding partners of Aβ oligomers. The interaction of Aβ oligomers with PrPC is important to synaptic dysfunction and loss. The binding of Aβ oligomers to PrPC has mostly been studied with synthetic peptides, cell culture, and murine models of AD by biochemical and biological methods. However, the molecular mechanisms underlying the relationship between Aβ oligomers and PrPC remain unclear, especially in the human brain. We immunohistochemically investigated the relationship between Aβ oligomers and PrPC in human brain tissue with and without amyloid pathology. We histologically demonstrate that PrPC accumulates with aging in human brain tissue even prior to AD mainly within diffuse-type amyloid plaques, which are composed of more soluble Aβ oligomers without stacked β-sheet fibril structures. Our results suggest that PrPC accumulating plaques are associated with more soluble Aβ oligomers, and appear even prior to AD. The investigation of PrPC accumulating plaques may provide new insights into AD