Autophagy gene overexpression in Saccharomyces cerevisiae perturbs subcellular organellar function and accumulates ROS to accelerate cell death with relevance to sparkling wine production

Lipids and membrane-associated proteins in autophagy

Autophagy is essential for the maintenance of cellular homeostasis and its dysfunction has been linked to various diseases. Autophagy is a membrane driven process and tightly regulated by membrane-associated proteins. Here, we summarized membrane lipid composition, and membrane-associated proteins relevant to autophagy from a spatiotemporal perspective. In particular, we focused on three important membrane remodeling processes in autophagy, lipid transfer for phagophore elongation, membrane scission for phagophore closure, and autophagosome-lysosome membrane fusion. We discussed the significance of the discoveries in this field and possible avenues to follow for future studies. Finally, we summarized the membrane-associated biochemical techniques and assays used to study membrane properties, with a discussion of their applications in autophagy.

Targeting autophagy to overcome drug resistance: further developments

Inhibiting cell survival and inducing cell death are the main approaches of tumor therapy. Autophagy plays an important role on intracellular metabolic homeostasis by eliminating dysfunctional or unnecessary proteins and damaged or aged cellular organelles to recycle their constituent metabolites that enable the maintenance of cell survival and genetic stability and even promotes the drug resistance, which severely limits the efficacy of chemotherapeutic drugs. Currently, targeting autophagy has a seemingly contradictory effect to suppress and promote tumor survival, which makes the effect of targeting autophagy on drug resistance more confusing and fuzzier. In the review, we summarize the regulation of autophagy by emerging ways, the action of targeting autophagy on drug resistance and some of the new therapeutic approaches to treat tumor drug resistance by interfering with autophagy-related pathways. The full-scale understanding of the tumor-associated signaling pathways and physiological functions of autophagy will hopefully open new possibilities for the treatment of tumor drug resistance and the improvement in clinical outcomes.

SPECIFIC FEATURES OF NITROGEN METABOLISM DURING FERMENTATION OF MUST FROM WHITE GRAPE VARIETIES GROWN IN THE ODESSA REGION

For wine quality management, nitrogen metabolism should be considered as a key process in the system “grape – wine.” Nitrogen is one of the dominant elements a grapevine receives from the soil. It is important in many biological processes of the plant itself and of the microorganisms involved in fermentation. Nitrogen-containing compounds are nutrients necessary for yeast growth, in particular, for stable fermentation. This group of compounds directly and indirectly affects the aromatic and taste qualities of wine during its maturation and largely determines its stability. Nitrogen compounds are transferred to wine directly from grapes and yeast during fermentation. Since their role in the formation and maturation of wine is significant, it is highly important to regulate their metabolism in the fermenting must. On analysing literature references and summarising the information on the metabolism of nitric substances, a scheme has been developed reflecting how these substances influence the formation of the quality characteristics of grape wines. The paper presents the results of studying the metabolism of total nitrogen and amino nitrogen in grape must during its fermentation. The grape variety considered in the research was Sukholimansky White bred by the National Science Centre “Tairov Institute of Viticulture and Winemaking” and harvested in 2015–2017. It has been established that nitrogen metabolism during fermentation does not depend on the feedings added. However, the yeast race affects the physicochemical parameters, namely the content of volatile acids. It has been observed that during fermentation, the amine nitrogen concentration decreases by 90% and the total nitrogen concentration by 40–50%. Regarding the factors that effect on the quality characteristics of wines produced in the South of Ukraine, the physicochemical parameters of wine materials can be improved by using the active dry yeast Vitilevure Quartz and the nutritional supplements Actiferm 1 and Actiferm 2, in combination with aeration. This allows revealing fruity aromas, and achieving the right acidity and harmony of taste due to the presence of the descriptors (butter, apple, peach, apricot, and geranium) characteristic of the grape variety Sukholimansky White.

Long-noncoding RNA MALAT1 sponges microRNA-92a-3p to inhibit doxorubicin-induced cardiac senescence by targeting ATG4a

The clinical application of doxorubicin (Dox) is limited due to its undesirable cardiotoxicity side effects. Cellular senescence plays an important role in Dox-induced cardiotoxicity. Exosomes derived from stem cells showed a therapeutic effect in Dox-induced cardiomyopathy (DIC). Hypoxia-preconditioned exosomes (exosome^Hypoxia) display pro-metabolism and pro-survival abilities. Several long-noncoding RNAs/microRNAs act as competing endogenous RNAs (ceRNAs) modulating DIC. No study investigated whether exosome^Hypoxia could attenuate DIC through modulating ceRNAs.Treatment of the human adipose-derived mesenchymal stem cells with hypoxia induced lncRNA-MALAT1 accumulation in the secreted exosomes. In addition, the lncRNA-MALAT1 was identified as an exosomal transfer RNA to repress miR-92a-3p expression. Silencing the lncRNA-MALAT1 in MSCs or miR-92a-3p overexpression in cardiomyocytes significantly impaired the rejuvenation induced by exosome^Hypoxia. TargetScan and luciferase assay showed that miR-92a-3p targeted the ATG4a 3' untranslated region. Silencing ATG4a blocked the anti-senescent effect of exosome^Hypoxia.This study identified the lncRNA-MALAT1 that functioned as ceRNA binding to miR-92a-3p, leading to ATG4a activation, thus improving mitochondrial metabolism. LncRNA-MALAT1/miR-92a-3p/ATG4a partially mediates the cardioprotective roles of exosome^Hypoxia in Dox-induced cardiac damage. Exosome^Hypoxia may serve as a potential therapeutic target against DIC.

Yeast Life Span and its Impact on Food Fermentations

Yeasts are very important microorganisms for food production. The high fermentative capacity, mainly of the species of the genus Saccharomyces, is a key factor for their biotechnological use, particularly to produce alcoholic beverages. As viability and vitality are essential to ensure their correct performance in industry, this review addresses the main aspects related to the cellular aging of these fungi as their senescence impacts their proper functioning. Laboratory strains of S. cerevisiae have proven a very successful model for elucidating the molecular mechanisms that control life span. Those mechanisms are shared by all eukaryotic cells. S. cerevisiae has two models of aging, replicative and chronological. Replicative life span is measured by the number of daughter cells a mother can produce. This kind of aging is relevant when the yeast biomass is reused, as in the case of beer fermentations. Chronological life span is measured by the time cells are viable in the stationary phase, and this is relevant for batch fermentations when cells are most of the time in a non-dividing state, such as wine fermentations. The molecular causes and pathways regulating both types of aging are explained in this review.