Archaeal species

N- ace t y Halos a m i n n u r o n i c acid. Other archaeal species contain cell walls made from thick polysaccharide layers containing acetate, glucuronic acid, galacto-samine, and glucose. 

Several of the protein transcription factors of archaea also resemble those of eukaryotes.267 268 However, in a comparison of DNA sequences from the complete genomes of four archaeal species, it was found that of 280 predicted transcription factors or transcription-associated proteins 168 were homologous to bacterial proteins and only 51 to eukaryotic proteins.268 This tends to confirm the ancient divergence of the three primary domains of life. 

In 1977, based on his evaluation of rRNA sequences and other data, Woese proposed that the archaebacteria were entitled to a branch of their own on the tree of life, now referred to as the archaea (Figure 171). Comparison of the genomes of archaeal species with... 

Until recently, less information was known regarding the enzymes involved in the biosynthesis of wyosine (or wyeosine), a complicated tri-cyclic modified nucleoside found in eukaryl and archaeal species. We now have a clearer understanding of how this base is constructed and many of the enzymes involved (Figure 38). It has... 

MCPs or MCP-like receptors appear to be involved in most, if not all, chemotactically responsive bacterial species (e.g., [410]). In all bacterial and archaeal species examined, the MCPs are clustered at the poles. In elongated bacterial species, the MCPs are located both at the poles and at regions along the length of the cells [257]. The number of MCPs varies a lot between species, from 5 in E. coli to 43 in Vibrio cholerae [288], which is the current record-holder. While the MCPs of many species are similar to those of E. coli and Salmonella, others are significantly different. A few examples follow. 

The production of PHA from the extremely halophilic Archaea has become the subject of recent research. Halophilic strains from the genera Haloarcula, Natrialba, Haloterrigena, Halococcus, Haloquadratum, Halorubrum, Natronobacterium, Natronococcus and Halobacterium have been reported as PHA accumulators [38]. Several halophilic Archaeal species, in the genera Haloferax and... 

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