Metallothioneins, Saccharomyces cerevisiae, and Heavy Metals: A Biotechnology Triad?

Metal ions are the least sophisticated chemical species that interact or bind to biomolecules. The yeast Saccharomyces cerevisiae represents a versatile model organisms used in both basic and applicative research, and one of the main contributors to the understanding of the molecular mechanisms involved in the transport, accumulation, and homeostasis of heavy metals. With a negatively charged wall, the yeast cells are very good biosorbents for heavy metals. In addition to biosorption, the metabolically active cells take up heavy metals via the normal membrane transport systems. Once in the cell, the toxicity of the heavy metals is controlled by various mechanisms, including sequestration by metal-binding proteins, such as the metallothioneins. Metallothioneins are cysteine-rich proteins involved in the buffering of excess heavy metals, both essential (Cu and Zn) and nonessential (Cd, Ag, and Hg). S. cerevisiae has two innate metallothioneins, Cup1 and Crs5, intensively investigated. Additionally, S. cerevisiae served as a host for the heterologous expression of a variety of metallothioneins from different species. This review focuses on the technological implications of expressing metallothioneins in yeast and on the possibility to use these transgenic cells in heavy metal-related biotechnologies: bioremediation, recovery of rare metals, or obtaining clonable tags for protein imaging

Calcium and Cell Response to Heavy Metals: Can Yeast Provide an Answer?

Despite constant efforts to maintain a clean environment, heavy metal pollution continues to raise challenges to the industrialized world. Exposure to heavy metals is detrimental to living organisms, and it is of utmost importance that cells find rapid and efficient ways to respond to and eventually adapt to surplus metals for survival under severe stress. This chapter focuses on the attempts done so far to elucidate the calcium-mediated response to heavy metal stress using the model organism Saccharomyces cerevisiae. The possibilities to record the transient elevations of calcium within yeast cells concomitantly with the heavy metal exposure are presented, and the limitations imposed by interference between calcium and heavy metals are discussed

Chemiluminescence Determination of the Total Antioxidant Capacity of Rosemary Extract

Total antioxidant capacity (TAC

Coffee and Yeasts: From Flavor to Biotechnology

Coffee is one of the most consumed beverages in the world, and its popularity has prompted the necessity to constantly increase the variety and improve the characteristics of coffee as a general commodity. The popularity of coffee as a staple drink has also brought undesired side effects, since coffee production, processing and consumption are all accompanied by impressive quantities of coffee-related wastes which can be a threat to the environment. In this review, we integrated the main studies on fermentative yeasts used in coffee-related industries with emphasis on two different directions: (1) the role of yeast strains in the postharvest processing of coffee, the possibilities to use them as starting cultures for controlled fermentation and their impact on the sensorial quality of processed coffee, and (2) the potential to use yeasts to capitalize on coffee wastes—especially spent coffee grounds—in the form of eco-friendly biomass, biofuel or fine chemical production

Anthocyanins and Anthocyanin-Derived Products in Yeast-Fermented Beverages

The beverages obtained by yeast fermentation from anthocyanin-rich natural sources (grapes, berries, brown rice, etc.) retain part of the initial pigments in the maturated drink. During the fermentation and aging processes anthocyanins undergo various chemical transformations, which include reactions with glycolytic products (especially pyruvate and acetaldehyde) or with other compounds present in the complex fermentation milieu (such as vinylphenols obtained from cinnamic acids by means of a yeast decarboxylase) yielding pigments which can be more stable than the initial anthocyanins. Overall, these compounds contribute to the organoleptic traits of the mature product, but also to the overall chemical composition which make the yeast fermented beverages important sources of dietary antioxidants. In this review, we focused on the studies regarding the changes underwent by anthocyanins during yeast-mediated fermentation, on the approaches taken to enrich the fermented beverages in anthocyanins and their derived products, and on the interrelations between yeast and anthocyanin which were of relevance for obtaining a high-quality product containing optimum amounts of anthocyanin and anthocyanin-derived products

Kcs1 and Vip1: The Key Enzymes behind Inositol Pyrophosphate Signaling in <i>Saccharomyces cerevisiae</i>

The inositol pyrophosphate pathway, a complex cell signaling network, plays a pivotal role in orchestrating vital cellular processes in the budding yeast, where it regulates cell cycle progression, growth, endocytosis, exocytosis, apoptosis, telomere elongation, ribosome biogenesis, and stress responses. This pathway has gained significant attention in pharmacology and medicine due to its role in generating inositol pyrophosphates, which serve as crucial signaling molecules not only in yeast, but also in higher eukaryotes. As targets for therapeutic development, genetic modifications within this pathway hold promise for disease treatment strategies, offering practical applications in biotechnology. The model organism Saccharomyces cerevisiae, renowned for its genetic tractability, has been instrumental in various studies related to the inositol pyrophosphate pathway. This review is focused on the Kcs1 and Vip1, the two enzymes involved in the biosynthesis of inositol pyrophosphate in S. cerevisiae, highlighting their roles in various cell processes, and providing an up-to-date overview of their relationship with phosphate homeostasis. Moreover, the review underscores the potential applications of these findings in the realms of medicine and biotechnology, highlighting the profound implications of comprehending this intricate signaling network

Homocysteine and vitamin therapy in stroke prevention and treatment: a review

Homocysteine (Hcy), a sulfur amino acid, is the only direct precursor for l-methionine synthesis through a reaction that requires vitamin B12, representing a connection with "one-carbon" units metabolism. Hcy catabolism requires vitamin B6 and as a consequence, alteration in folic acid and B vitamins status impairs Hcy biotransformation. Numerous studies have indicated that Hcy is an independent risk factor for cardio- and cerebrovascular diseases. In the last decade, several clinical trials have investigated the possible correlation between the use of folic acid and vitamins B6 and B12 for lowering Hcy plasma concentration and the reduced risk of stroke or its recurrence. This review is aimed to present some aspects of Hcy biochemistry, as well as the mechanisms through which it exerts the toxic effects on the vascular endothelium. We also discuss the results of some of the clinical trials developed to investigate the beneficial effects of vitamin therapy in the prevention and management of stroke

Correction: Gruia, M.-I. et al. The Antioxidant Response Induced by Lonicera caerulaea Berry Extracts in Animals Bearing Experimental Solid Tumors. Molecules 2008, 13, 1195-1206

In the original published version of this paper [1] we omitted to acknowledge that the work was supported by a grant-in-aid. The acknowledgment is hereby published as follows. [...

Valorization of Spent Brewer’s Yeast Bioactive Components via an Optimized Ultrasonication Process

The increasing need for sustainable waste management and food fortification requires continuous agri-food biotechnological innovation. Spent brewer’s yeast (SBY) is a mass-produced underutilized by-product of the brewery industry and has elevated bioactive potential. The current study presents a streamlined ultrasonic SBY cell lysis method, with the main goal of bioactive compound valorization. The influence of selected ultrasonication parameters on protein release and, implicitly, on the cell disruption efficiency, was assessed. The SBY derivatives resulting from the ultrasonic cell lysis were SBY extracts (SBYEs) and cell walls (SBYCWs), which were evaluated in terms of protein content, antioxidant activity (AOA) and total polyphenol content. Scanning electron microscopy (SEM) and FT-IR spectroscopy were used to characterize SBYCWs in relation to the morphological and chemical transformations that follow ultrasonic yeast cell disruption. The optimal ultrasonication conditions of 6.25% SBY concentration, 40 °C and 33.33% duty cycle (DC) ensured the most efficient lysis. The SBY derivatives with the most elevated antioxidant activity were obtained at temperatures below 60 °C. SBYCWs had the highest polyphenol content and a relatively high content of β-glucan under these parameters. Optical microscopy and SEM confirmed the release of intracellular content and separation of SBYCWs