Involvement of the High-Osmolarity Glycerol Pathway of Saccharomyces Cerevisiae in Protection against Copper Toxicity

Abstract

Although essential for life, copper is also potentially toxic in concentrations that surpass physiological thresholds. The high-osmolarity glycerol pathway of yeast is the main regulator of adaptive responses and is known to play crucial roles in the responses to various stressors. The objective of this research is to determine whether the HOG pathway could be activated and to investigate the possible interplay of the HOG pathway and oxidative stress due to copper exposure. In this research, we demonstrate that copper could induce oxidative stress, including the elevated concentrations of reactive oxygen species (ROS) and malondialdehyde (MDA). Increased combination with GSH, increased intracellular SOD activity, and the up-regulation of relevant genes can help cells defend themselves against oxidative toxicity. The results show that copper treatment triggers marked and prolonged Hog1 phosphorylation. Significantly, oxidative stress generated by copper toxicity is essential for the activation of Hog1. Activated Hog1 is translocated to the nucleus to regulate the expressions of genes such as CTT1, GPD1, and HSP12, among others. Furthermore, copper exposure induced significant G1-phase cell cycle arrest, while Hog1 partially participated in the regulation of cell cycle progression. These novel findings reveal another role for Hog1 in the regulation of copper-induced cellular stress.

Enabling growth-decoupled Komagataella phaffii recombinant protein production based on the methanol-free PDH promoter

“…Additionally, the absence of lower molecular weight bands on SDS-PAGE, which would indicate CalB proteolysis, suggests that no active host proteases were present. Moreover, this dynamic expression was also observed in S. cerevisiae after applying different stressing conditions to activate P hsp12 , being followed by GFP fluorescence (Karreman and Lindsey, 2005;Xiong et al, 2018) and HSP12 relative transcript levels (Chowdhary et al, 2017;Ren et al, 2022). In accordance, P DH activation in K. phaffii also seemed to decrease over time, although the stressing conditions were maintained.…”

Electrochemical Control of Cell Metabolism Improves Ethanol Production of Zymomonas mobilis in an Electro-Fermentation System

“…Thus, glucose consumption declined. The glycerol generated from the strain was used to protect cells from oxidizing stress …”

“…Based on the previous voltage and substrate optimization results, glucose consumption and the production of ethanol and succinate were enhanced in the CA chamber, despite a decrease in ethanol and succinate yields, indicating that the reducing condition with extra electrons available promoted the total carbon flux. In the AN chamber, glycerol production was improved under oxidizing conditions because glycerol is an antioxidant in the cells …”

“…For specific electrode voltage during the The glycerol generated from the strain was used to protect cells from oxidizing stress. 18 By calculating the electron balance, the CE values of the EF system were 329.5% at the 3 V and 99.81% at the 5 V conditions, which indicated that more electrons delivered by the current could participate in the production of the reduced products under the 3 V condition. In fact, it is common that the increased reduced products are larger than that generated from electrons delivered by the EF system.…”

“…In the AN chamber, glycerol production was improved under oxidizing conditions because glycerol is an antioxidant in the cells. 18 Correlation between Extracellular ORP and Intracellular Cofactors. To elucidate the mechanism underlying Z. mobilis metabolism flux changes in the electro-fermentation, extra-and intracellular redox conditions were analyzed simultaneously.…”