Metabolic Fingerprinting of Muscat of Alexandria Grape Musts during Industrial Alcoholic Fermentation Using HS-SPME and Liquid Injection with TMS Derivatization GC-MS Methods.

Muscat of Alexandria is one of the most aromatic grape cultivars, with a characteristic floral and fruity aroma, producing popular appellation of origin wines. The winemaking process is a critical factor contributing to the quality of the final product, so the aim of this work was to study metabolomic changes during the fermentation of grape musts at the industrial level from 11 tanks, 2 vintages, and 3 wineries of Limnos Island. A Headspace Solid-Phase Microextraction (HS-SPME) and a liquid injection with Trimethylsilyl (TMS) derivatization Gas Chromatography-Mass Spectrometry (GC-MS) methods were applied for the profiling of the main volatile and non-volatile polar metabolites originating from grapes or produced during winemaking, resulting in the identification of 109 and 69 metabolites, respectively. Multivariate statistical analysis models revealed the differentiation between the four examined time points during fermentation, and the most statistically significant metabolites were investigated by biomarker assessment, while their trends were presented with boxplots. Whilst the majority of compounds (ethyl esters, alcohols, acids, aldehydes, sugar alcohols) showed an upward trend, fermentable sugars, amino acids, and C6-compounds were decreased. Terpenes presented stable behavior, with the exception of terpenols, which were increased at the beginning and were then decreased after the 5th day of fermentation.

Would 20 nm Filtered Fetal Bovine Serum-Supplemented Media Support Growth of CHO and HEK-293 Cells?

Virus safety of fetal bovine serum (FBS) is a critical issue for cell culture and clinical applications of cell therapies. The size exclusion filtration of FBS-supplemented cell culture media through small-size virus retentive filter paper is presented to investigate its effect on cell culture. A substantial proportion of proteins (ca. 45%) was removed by nanofiltration, yet important transport proteins (albumin, fetuins, macroglobulins, transferrin) were unaffected. The cell viability of Chinese hamster ovary (CHO) and human embryonic kidney 293 (HEK-293) cells that were grown in media supplemented with nanofiltered FBS was surprisingly high, despite the observed protein losses. Protein depletion following nanofiltration resulted in detectable levels of autophagy markers.