Archae

Data indicating participation of PolyPs in overcoming stress were obtained in Propi-onibacteria. The PolyP component in the 31P NMR spectra of Propionibacterium acne increased after ultraviolet light irrardiation (Kjeldstad and Johnson, 1987) and after hyperthermia treatment (Kjeldstad et al., 1988). Such treatments, carried out in triplicate, induced an increase in the PolyP content, as observed by 31P NMR spectroscopy. One of the explanations for this might be that hyperthermia and ultraviolet light induce an oxidative stress in the cells, which increases the amount of PolyP (Kjeldstad and Johnson, 1987 Kjeldstad et al., 1988). 

To summarise, it should be said that the PolyP content and chain length in Propionibac-teria are strongly dependent on the carbon source. These bacteria possess polyphosphate glucokinase and are able to directly utilize PolyP for glucose phosphorylation. 

PolyP metabolism in Archae, a very ancient and heterogenic domain of prokaryotes, has been little studied. PolyP and PolyP-dependent enzymes were observed in some representatives of this domain (Scherer and Bochem, 1983 Skorko, 1989 Trotsenko and Shishkina, 1990 Rudnick et al., 1990 Andreeva et al., 2000 Smirnov et al., 2002a,b Cardona et al., 2002). 

Methanosarcinafrisia accumulates phosphate up to a level of 14 % of its dry weigh (Rud-nick etal, 1990). The phosphate is stored as PolyP, as shown by31P NMR spectroscopy. This archaeon accumulate more phosphate in the presence of methanol as the carbon source, when compared with CO2 and H2 as the only carbon and energy sources (Rudnick et al., 1990). 

It should be noted that yeast possesses PolyPs in nearly all cell compartments (see Chapter 5) and the compartmentation of these biopolymers should be taken into consideration when analysing their accumulation and utilization. 

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If a phylogenetic comparison is made of the 16S-Iike rRNAs from an archae-bacterium Halobacterium volcanii), a eubacterium E. coli), and a eukaryote (the yeast Saccharomyces cerevisiae), a striking similarity in secondary structure emerges (Figure 12.40). Remarkably, these secondary structures are similar despite the fact that the nucleotide sequences of these rRNAs themselves exhibit a low degree of similarity. Apparently, evolution is acting at the level of rRNA secondary structure, not rRNA nucleotide sequence. Similar conserved folding patterns are seen for the 23S-Iike and 5S-Iike rRNAs that reside in the... 

Among other oxidizing agents that have been used to accomplish the conversion of ArCHs to ArCHO are ceric ammonium nitrate, ° ceric trifluoroa-cetate, and silver(II) oxide.Oxidation of ArCHa to carboxylic acids is considered at 19-11. 

Conversion of ArCHa to ArCHO can also be achieved indirectly by bromination to give ArCHBr2 (14-1), followed by hydrolysis (10-2). 

Taphonomy is the branch of science that studies the processes of decay and fossilization of the remains of dead organisms. The term taphonomy (from the Greek taphos, burial and nomos, law) was introduced during the first half of the twentieth century to describe the study of the transition of the dead remains of organisms from the biosphere to the lithosphere. Archae-ologically related taphonomic studies began much later, near the end of the century (O Connor 2005). 

There is, however, little systematic understanding of the factors that control preservation for the wide range of materials encountered archae-ologically, and virtually nothing in the way of predictive models. Soil pH (crudely speaking, acidity see Section 13.1) and Eh (redox potential, or... 

Although spliceosomal introns appear to be limited to eukaryotes, the other intron classes are not. Genes with group I and II introns have now been found in both bacteria and bacterial viruses. Bacteriophage T4, for example, has several protein-encoding genes with group I introns. Introns appear to be more common in archae-bacteria than in eubacteria. 

Organ, R. M., The Value of Analysis of Archaeological Objects, Archae-... 

Methanopterin (20) is a folate analogue that is isolated from an archae-bacteria, Methanosarcina thermophila, and the bacteria produces methane from CO2 under anaerobic conditions [18-24]. In the methane-producing metabolic process (Scheme 2), tetrahydromethanopterin (21) is known to work as a cofactor for the reduction of the Ci unit. Here, 21 accepts a formyl group that originates from CO2 and transforms it into the formyl... 

The dogma that glycoproteins occur exclusively in eucaryotic cells had to be revised in the last twenty years. Bacterial glycoproteins form the outer surface (S)-layer of archae- and eubacteria [61,62]. In analogy to eucaryotic cells, partly sulfated oligosaccharides attached to Asn or Thr are found in halobacteria. Nucleoside-diphosphate-activated oligosaccharides were identified as intermediates in the biosynthesis of the S-layer of the eubacterium Bacillus alvei [63] and the archaebacterium Methanothermus fervidus [64],... 

There were 37 distinct enzymes that contain molybdenum or tungsten known by the end of 1997. The enzymes are diverse in function, broadly distributed, and include oxidases, reductases, dehydrogenases, a transhydroxylase, and a hydratase. The Mo enzymes are found in eubacteria, archae, protista, fungi, plants, and animals (including humans) and are essential for respiration and carbon and nitrogen assimilation. Several of the enzymatic substrates and products are key components in the nitrogen, sulfur, selenium, carbon, and arsenic cycles and have major biological and environmental impact. 

In order to find the energy x, we use first order perturbation theory. The degenerate orbitals involved are the doubly occupied AO s of Cl- and I-, and the empty NBMO of ArCHa. The necessary matrix elements are found as before in terms of the CC1 and Cl resonance integrals fta, ft. Solving the resulting three-row secular equation, we find for the perturbed energies—... 

In addition, PolyPs are most likely involved in the regulation of enzyme activities by participation in their phosphorylation. A protein phosphorylation process, using not ATP but high-polymer PolyPs, was revealed in the archae Sulfolobus acidocaldarius (Skorko, 1989). Tripolyphosphate was observed to be a phosphodonor of selective protein phosphorylation of rat liver microsomal membrane (Tsutsui, 1986). 

In the opinion of some investigators, the PP-dependent H+-pumps are more ancient than the H+-ATPases (Baltscheffsky, 1997 Baltscheffsky et al., 1999). However, it should be noted that all contemporary microorganisms, including the most ancient archae, possess in their membranes H+-ATPases of different types (Nelson, 1992). 

According to this hypothesis (Margulis, 1993), the eukaryotic cell is a result of symbiosis of different prokaryotic cells, where mitochondria originated from eubacteria, and chloroplasts - from cyanobacteria, and vacuoles - from archae. 

The homology of V-ATPases and pyrophosphatases of the vacuoles and plasma membranes of archae indicates a possibility of endosymbiotic descent of vacuoles from ancient representatives of this domain (Nelson, 1992). 

A. V. Smirnov, T. V. Kulakovskaya and I. S. Kulaev (2002a). Phosphate accumulation by an extremely halophilic archae Halobacterium salinarium. Proc. Biochem., 37, 643-649. 

Archae Eubact Eukar Archae Eubact Eukar... 

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