Thermoprotectants

Among aminoacetylenes with different numbers of morpholinopropynyl groups, a substance has been found that displays antihypotoxic, thermoprotecting properties, increasing the stability of animals to intoxication by phosphor organic compounds and the salts of toxic metals. Because the efficiency of this substance exceeds that of azomopine 103 and it is nontoxic, it could be of interest to clinical medicine after additional studies. 

Extrinsic stabilization from low-molecular-mass "thermoprotectants." The intrinsic stability of a protein reflects selection for an amino acid sequence that confers on the protein the appropriate balance between rigidity and flexibility that is required for physiological function under the thermal conditions facing the organism. This being said, the stability of the protein in vivo may be modulated by extrinsic factors, including pH, which varies with temperature, and low-molecular-mass organic osmolytes, whose concentrations may be tern-... 

Other organic solutes found in thermophilic archaea likely play roles as thermoprotectants, although there have been few in vitro studies in which the effects of these solutes on protein stability have been tested. Among the putative thermoprotectants in hyperthermophilic archaea is di-myo-inositol-1,1 -phosphate (DIP) (see figure 6.2 for the structure of this... 

T. neapolitana also adds mannose moieties onto the inositol rings, and this new phosphodiester, di-2-0-(3-mannosyl-di-myo-inositol-l,l -phosphate (Table 1) also appears to accumulate at high growth temperatures. However, DIP is still the major solute accumulated in T. neapolitana at supraoptimal growth temperatures (Martins et al., 1996). The addition of mannose to DIP produces a very unique phosphodiester, yet we know very little about why it is synthesized and accumulated. The involvement of these inositol solutes in thermoprotection... 

According to our results, the presence of an osmolyte in the growth medium and a disaccharide in the dehydration step was a preferred combination. When only the osmolytes were added to the growth medium and no thermoprotectant was used to dehydrate, the recovery was weakly improved (only one order of magnitude). 

It has recently been shown that introduction of a small, hydrophobic molecule like isoprene may lead to a more ordered and better packed lipid membrane as revealed by MD simulations. The stabilized membrane is then protected against temperature-induced disordering of the tails. Similar thermoprotective effects are induced by cholesterol which also increases the molecular packing of the tails and, in contrast to isoprene, affects the dynamics of the lipids in the bilayer. ... 

Rodriguez-Huezo, M.E., Duran-Lugo, R., Prado-Barragan, L.A. et al. 2007. Pre-selection of protective colloids for enhanced viability of Bifidobacterium bifidum following spray-drying and storage, and evaluation of aguamiel as thermoprotective prebiotic. Food Res. Int. 40 1299-1306. 

DIP was initially identified in Pyrococcus woesei and Methanococcus igneusP Later, this solute was detected in other hyperthermophilic archaea, namely in Pyrodictium occultum, and in Pyrococcus and Thermococcus spp. In several species of the Thermococcales large increases in the levels of DIP are observed at growth temperatures above the optimum, leading to the view that this solute has a thermoprotective role in these oiganisms. ... 

It should be mentioned that lyotropic salts, such as ammonium sulfate and potassium phosphate, have a thermoprotective effect on enzymes that rivals the effect of organic solutes in vitro. However, it is unlikely that these salts could play a role in vivo, since the large concentrations required for protection would interfere with enzyme activity and metabolic regulation, and have, in fact, never been found... 

Bonilla AQ, Oliveira LJ, Ozawa M, Newsom EM, Lucy MC, Hansen PJ. 2011. Developmental changes in thermoprotective actions of insulin-like growth factor-1 on the preimplantation bovine embryo. Mol Cell Endocrinol 332(1-2) 170-179. 

Garcia-Estepa, R., Argandona, M., Reina-Bueno, M., Capote, N., Iglesias-Guerra, F., Nieto, J. J., Vaigas, C. The ectD gene, which is involved in the synthesis of the compatible solute hydroxyectoine, is essential for thermoprotection of the halophUic bacterium Chromohalobacter salexigens. J Bacterial. 2006,188, 3774-3784. 

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