Archaebacteria are a group of organisms distinct from all others at the highest level. They are no more related to other bacteria, i.e., the true bacteria (eubacteria) than they are to eucaryotic cells. Archaebacteria, eubacteria and (some aspect of) the eucaryotic cell each represent separate primary lines of descent.
Streptococcus agalactiae (group B) was grown in Todd-Hewitt broth (36.4 g l-1, pH 7.8) in a Braun Fermenter (type B20) to investigate the conditions of optimal bacterial growth and maximal production of CAMP factor. The influence of different gas atmospheres (air, N2, CO2, and gas mixtures) on growth, CAMP production and chain length of S. agalactiae was studied. The organisms grew best in the presence of 2% (w/v) glucose, at pH 6.2, with a constant flow of CO2. The number of diplococci and monococci under these conditions reached almost 80% of the total population.
The acidothermophilic Archaebacteria, Sulfolobus acidocaldarius and S. brierleyi, oxidized elemental sulfur anaerobically producing sulfuric acid by using Mo (VI) as an apparent electron acceptor. Molybdenum reduction resulted in the formation of a blue color which was intensified in the presence of aluminum at concentrations of 20–50 mM. Molybdenum was not reduced when S. brierleyi was grown anaerobically on yeast extract as an energy source, suggesting that the organic substrate was utilized in a fermentative metabolism mode.
The archaebacteria currently consist of several distinct subgroups including methanogens, extreme halophiles and certain thermoacidophiles. The lipids of archaebacteria are distinguished from those of other prokaryotes and eukaryotes by the absence of fatty acid glycerol ester lipids and the predominance of nonsaponifiable lipids. The lipid composition of the archaebacteria consists of isoprenoid and hydroisoprenoid hydrocarbons and isopranyl glycerol ether lipids.
Methanobrevibacter arboriphilus DNA was isolated after treatment of the cells with bacitracin in a sucrose containing growth medium. Hind III restriction fragments of the DNA were inserted into an expression vector plasmid. The newly constructed plasmids when introduced into E. coli gave rise to the synthesis of polypeptides coded for by the methanogen DNA. The expression of genetic information from the Methanobrevibacter DNA in E. coli is efficient as judged by the total molecular weight of the polypeptides found as compared to the length of the Methanobrevibacter DNA carried on the plasmids.
The requirement for the small ribosomal 5S RNA as an integral part of the protein synthesizing machinery, the ribosome, has been conserved throughout the course of evolution. Eubacterial, eukaryotic, archaebacterial and chloroplast 5S RNAs have been used for protein binding studies, reconstitution experiments and structural analysis with the single strand specific ribonuclease S1 These comparative studies reflect the phylogenetic relationship of the individual species examined; besides the two major classes, eubacterial and eukaryotic 5 S RNA, archaebacterial 5S RNA represents a further class, which is structurally and functionally distinct.
