Thermal tolerance

Three cyanide-degrading nitrilases were recently cloned and purified and their kinetic profiles were evaluated in order to better understand their applicability to cyanide bioremediation. CynD from Bacilluspumilus Cl and DyngD from Pseudomonas stutzeri exhibit fairly broad pH profiles with >50% activity retained across pH 5.2 to pH 8.0 while the CHT (NHase) from Gloeocercospora sorghi exhibited a more alkaline pH activity profile with almost all of its activity retained at pH 8.5, slightly lower thermal tolerance, and quite different metal tolerance compared with the two bacterial enzymes [46]. 

Thermal tolerance of isolated muscle tissue and of proteins, such as adenylate kinase and actomyosin, of small and large varieties of Black Sea horse-mackerel has been studied by Altukhov (1962) and Glushankova (1967). Johnston et al. (1973) focused on determining the thermoresistance of ATPase... 

The maj ority of these new plants are corn dry-grind ethanol plants. Approximately 2.5-2.7 gal of ethanol, 17.5 lb of dried distiller s grain (DDG), and 17 lb of carbon dioxide are produced from each bushel of corn processed through a corn dry mill (2). Since 1980, process improvements in enzymes, thermal-tolerant yeasts, molecular sieves, and cogeneration have achieved a 50% reduction in the energy required to produce ethanol from corn (2). Further improvements in efficiencies and reductions in production costs can be expected in the future. 

Thermal Tolerance Ranges Vary Greatly Stenotherms and Eurytherms... 

Before examining these types of variation in the heat-shock response and the potential roles this variation may play in setting thermal tolerance limits and biogeographic patterning, an important aspect of experimental design must be discussed. Each of the major characteristics of the heat-shock response listed in the previous paragraph involves interactions between tern-... 

Membrane-based processes generally are highly sensitive to changes in temperature. These sensitivities may be much greater than those exhibited by processes occurring in the aqueous phase of the cell, and because of this membranes may play vital roles in establishing organisms thermal tolerance limits. Why are... 

Neural activity, which involves transmembrane ion fluxes and the release and uptake of chemical transmitters at synapses, is a highly important membrane-based function and a primary site of thermal perturbation in animals. Both axonal conduction and, especially, synaptic transmission may be involved in setting thermal tolerance limits. 

Adaptation of the nervous system to temperature is likely to play a major role in governing the thermal tolerance ranges and thermal optima of animals (Cossins and Bowler, 1987). Conduction along axons and, particularly, transmission of signals at synapses are strongly affected by temperature. It is probable, therefore, that alterations in the properties of neural membranes will be found to correlate closely with changes in the thermal sensitivity of behavior. The nearly perfect homeoviscous adaptation of brain synaptosomes from differently... 

Mechanisms establishing thermal tolerance What mechanisms set the upper and lower thermal tolerance limits for organisms Can we identify weak links in the physiological chain that are responsible for establishing upper and lower thermal tolerance limits Are all links weak ... 

How do thermal tolerance limits compare to habitat (body) temperatures ... 

Figure 7.45. Thermal tolerance relationships of porcelain crabs. Relationship of habitat temperature to upper lethal temperature for 19 congeners of Petrolisthes. (Figure modified after Stillman and Somero, 2000.)...

Stillman, J.H., and G.N. Somero (2000). A comparative analysis of the upper thermal tolerance limits of Eastern Pacific porcelain crabs (genus Petrolisthes). influences of latitude, vertical zona-tion, acclimation and phylogeny. Physiol. Biochem. Zool. 73 200-208. 

Nobel P. S. (1984) Extreme temperatures and thermal tolerances for seedlings of desert succulents. Oecologia 62, 310-317. 

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