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Physiology of Ethanol Production by Zymomonas mobilis
Published in Ayerim Y. Hernández Almanza, Nagamani Balagurusamy, Héctor Ruiz Leza, Cristóbal N. Aguilar, Bioethanol, 2023
Laura Andrea Pérez-García, Cindy Nataly Del Rio-Arellano, David Francisco Lafuente Rincón, Norma M. De La Fuente-Salcido
In Figure 2.4, the yeast the Hog1 gene is responsible for encoding the high osmolarity glycerol pathway (HOG), this pathway mainly encodes two enzymes GPD1 and GPD2 that catalyze the conversion of dihydroxyacetone phosphate (DHAP) through glycerol-3-phosphate (G3P) to glycerol. The Fps1 channel helps to glycerol accumulation and contributes to raising the osmotic pressure within the cell. Within the stress response are the proteins trehalose-6-phosphate synthase (TPS) and trehalose-6-phosphate phosphatase (TPP), enzymes responsible for the synthesis of trehalose. In the same way, heat shock transcription factor (Hsf1) induces the production of HSPs [40]. Also, in Figure 2.4 in Z. mobilis the Zms4 and Zms6 genes are involved in direct sRNA and target mRNA interactions. The accumulation of ethanol within cells under stress increases the expressions of these genes. Increasing the level of Zms4 accelerates ethanol catabolism through upregulation of the aldehyde dehydrogenase gene (SsdA/ZmsZMO1754) directly and the alcohol dehydrogenase 1 gene (AdhA) indirectly to mask ethanol to other carboxylic acids. On the other hand, Zms6 upregulated under ethanol stress regulates the expression of the lysine export Zms1437 gene and negatively regulates the expression of the methylase gene of Zms1934 N-6 DNA to improve ethanol tolerance and avoid import of methylated DNA created by ethanol damage, respectively. However, several regulatory functions of this Zms6 gene are still unknown. Otherwise, Zms16 gene interacts directly as a target only with the gen Zms6 [41].
Alterations in Cellular Enzyme Activity, Antioxidants, Adenylates, and Stress Proteins
Published in Alan G. Heath, Water Pollution and Fish Physiology, 2018
Stress proteins are not limited to stressed cells. They are found in nearly all cells and their function is to regulate folding, assembly, and aggregation of other proteins. They are often collectively called chaperones for this reason. A primary mechanism of toxicity involves protein denaturation which results in molecular aggregation and misfolding (Hightower, 1991). This causes binding of a protein called heat shock factor (HSF) to controlling genes (promoter) which then activate transcription of the stress protein genes. Synthesis of stress proteins then occurs to facilitate the repair of the denatured proteins. As the proteins are repaired, stimulation of the HSF declines slowing the induction process so the feedback loop is completed.
Glossary of scientific and technical terms in bioengineering and biological engineering
Published in Megh R. Goyal, Scientific and Technical Terms in Bioengineering and Biological Engineering, 2018
Stress protein (Heat shock proteins, HSP) are a group of proteins induced by heat shock. The most prominent members of this group are a class of functionally related proteins involved in the folding and unfolding of other proteins. Their expression is increased when cells are exposed to elevated temperatures or other stress. This increase in expression is transcriptionally regulated. The dramatic upregulation of the heat shock proteins is a key part of the heat shock response and is induced primarily by heat shock factor (HSF).
Adverse health effects and stresses on offspring due to paternal exposure to harmful substances
Published in Critical Reviews in Environmental Science and Technology, 2023
Jiaqi Sun, Miaomiao Teng, Fengchang Wu, Xiaoli Zhao, Yunxia Li, Lihui Zhao, Wentian Zhao, Keng Po Lai, Kenneth Mei Yee Leung, John P. Giesy
Adult sire BALB/c mice exposed to MC-LR gave birth to offspring with reduced litter size and weight of pups and abnormalities of the lung (Meng et al., 2020). The mechanisms of the toxic effects are shown in Figure 4. After exposure to MC-LR, multiple piRNAs in sperm were downregulated, and pulmonary pathology resulted in abnormal activation of Wnt/β-catenin signaling to MC-LR. A large number of piRNA-rich target genes involved in the regulation of the embryo implantation pathway were downregulated. The expression of heat shock protein 90 α (hsp90α), protein phosphatase 2A (PP2A) and heat shock factor 1 (Hsf1) was inhibited in the testes of male mice after exposure to MC-LR, making the tissues and cells unprotected from stresses such as oxidative stress. Such changes were found to result in abnormal activation of the catenin signaling pathway, Wnt/β, in lung tissues of the offspring (Xu et al., 2008). In addition, it was found that acute administration of stress-sensitive glucocorticoid receptor agonists (using the ordinary glucocorticoid dexamethasone (Dex)) would affect the RNA payload of mature sperm within three hours after exposure (Gapp et al., 2021). It further affects the transcriptional trajectory of early embryos determined by single embryo sequencing and the metabolism of offspring.