Archaea hyperthermophilic species

In the hyperthermophilic Archaea, NAD(P)-reactive enzymes are involved in recycling the reduced cofactors to produce H2 as a waste product as in the case of the NADPH oxidising hydrogenases from the hyperthermophilic Archaea, e.g. Pyrococcus species (Bryant and Adams 1989 Pedroni et al. 1995) and Thermococcus litoralis (Rakhely et al. 1999). These enzymes are also heterotetramers (Fig. 2.2C) with an apparently similar organisation of subunits and prosthetic groups to the Eubacterial examples of Group 5. 

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. ... 

Hyperthermophilic record The species Pyrolobusfumarii, lives at 113 °C. About 20 species of hyperthermophiles live at temperatures above 100°C. Acidophilic Archaea live at a pH of less than 5 and can survive at values lower than 1. Alkaliphilic Archaea live at pH values higher than 10 and can survive at a pH above 12. 

Although the membrane components containing pranyl chains are common to all Archaea, it is not the case for the sulfur derivatives of the sulfur-dependent thermophiles and hyperthermophiles that occur especially in, or in the vicinity of, underwater and terrestrial hydrothermal vents. Thus, in the species Thermococcus tadjuricus (strain Ob9) and Thermococcus acidaminovorans (strain Vc6bk), collected from deep-sea hydrothermal vents,a series of cyclic polysulfides was found that included lenthionine, which previously had been isolated from the terrestrial mushroom Lentinus edodes (Ritzau et al., 1993). Several of these compounds are presented in Figure 6.13. Similar polysulfides were isolated from red algae, such as Chondria califomica, and ascidians, such as certain Lissoclinum sp. (see Chapters 13 and 28). 

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