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Interconnection between PHA and Stress Robustness of Bacteria
Published in Martin Koller, The Handbook of Polyhydroxyalkanoates, 2020
Stanislav Obruca, Petr Sedlacek, Iva Pernicova, Adriana Kovalcik, Ivana Novackova, Eva Slaninova, Ivana Marova
To defend against the harmful effect of osmotic fluctuations, bacterial cells, regardless of their salinity preferences, developed sophisticated protective mechanisms. Bacterial cells are able to detect the variances in external osmotic pressure by the action of various membrane-associated mechanosensitive channels and osmotic transporters. The osmosensing capability enables cells to react to fluctuations in osmolarity. The exposure of the cells to osmotic up-shock induces the synthesis of osmolytes (also called compatible solutes). These small organic molecules such as trehalose, ectoines, glutamate, glycine betaine, etc. compensate the extracellular osmotic pressure and therefore protect bacterial cells from the harmful effect of osmotic up-shock. Apart from their balancing function, these small molecules also act as chemical chaperones and therefore protect various sensitive biomolecules from denaturation and loss of biological activity [58]. When the opposite situation occurs and cells are introduced into a hypotonic environment, water as well as osmolytes are pumped out of the cells by so-called “mechanosensitive channels” to protect the cell from hypotonic lysis [59,60].
Non-targeted metabolomics analyses by mass spectrometry to explore metabolic stress after six training weeks in high level swimmers.
Published in Journal of Sports Sciences, 2021
Robin Pla, Estelle Pujos-Guillot, Stéphanie Durand, Marion Brandolini-Bunlon, Delphine Centeno, David B. Pyne, Jean-François Toussaint, Philippe Hellard
One of the results that opens up prospects for future research is the significantly higher ionic concentration (~200%) of 4-phenylbutanic acid-O-sulphate in the two swimmers who reported the lowest levels of fatigue, the highest levels of motivation and the best sleep in the study. The moxocarboxylic 4-phenylbutyric acid is produced endogenously at the cell membrane level. This molecule has been identified as a chemical chaperone known to assist proteins in their maturation by improving, in particular, the folding capacity of the endoplasmic reticulum. They serve as a “quality control system”, recognising, retaining and targeting misfolded proteins for degradation (Welch & Brown, 1996). Investigators have suggested the potential role of these chemical chaperones in the treatment of stress-related neurodegenerative diseases but also in diabetes (Lee et al., 2011). Sodium phenylbutyrate is the salt of 4-phenylbutyric acid and used in the treatment of diseases such as urea cycle disorders by ammonia uptake (Ozcan et al., 2006). Sodium phenylbutyrate can reduce oxidative stress has anti-inflammatory effects, and improves insulin sensitivity and promotes glucose metabolism in skeletal muscle (Ozcan et al., 2006; Lee et al., 2011). We speculate the higher concentrations of 4-phenylbutanic acid-O-sulphate in the two swimmers who reported less subjective fatigue, higher motivation and better sleep quality suggests a relationship between peripheral membrane chemical metabolism and behavioural indices. Understanding the mechanisms of this possible interaction requires future research.
Using chemical chaperones to increase recombinant human erythropoietin secretion in CHO cell line
Published in Preparative Biochemistry and Biotechnology, 2019
Mehri Mortazavi, Mohammad Ali Shokrgozar, Soroush Sardari, Kayhan Azadmanesh, Reza Mahdian, Hooman Kaghazian, Seyed Nezamedin Hosseini, Mohammad Hossein Hedayati
Chemical chaperones are small molecules that assist molecular chaperones to fold a protein in endoplasmic reticulum also integrate into the protein structure to protect its folding in the secretory pathway. Molecular chaperones and chemical chaperones collaborate with each other to reduce misfolded protein response and enhance protein secretion.[5,15] Such collaboration happens as a result of the increased activity of molecular chaperones after treatment of the cells by chemical chaperone. Also chemical chaperones cooperate with molecular chaperones by adjust their activity.[16] Chemical chaperones are from different groups of components, including polyols such as glycerol, methylamines such as trimethylamine N-oxide (TMAO), sugar, and amino acid derivatives. It is worth mentioning that media optimization is currently the most important plan in recombinant protein production using CHO cell line. The existing challenges in bioprocessing tasks such as low yield and aggregation can be studied and resolved to improve protein production using chemical chaperones through handling molecular chaperones.[3]