Peptidoglycan types of bacterial cell walls and their taxonomic implications.

Strains of 2, 4-diaminobutyric acid-containing coryneform bacteria were degraded by acid methanolysis and the non-hydroxylated fatty acid esters released examined by thin-layer and gas chromatography. The major fatty acid structural types were straight-chain, anteiso- and iso-methyl branched-chain acids. Polar lipids of the test strains were examined by two-dimensional thin-layer chromatography. All strains possessed very characteristic polar lipid patterns consisting of diphosphatidylglycerol, phosphatidylglycerol and a number of uncharacterized glycolipids. Menaquinones (vitamin K) were the sole isoprenoid quinones detected in the test strains. Corynebacterium insidiosum, Cor. michiganense, Cor. nebraskense and Cor. sepedonicum contained unsaturated menaquinones with nine isoprene units, whereas unsaturated menaquinones with 10 isoprene units predominated in strains of Cor. iranicum and Cor. tritici and a strain labelled Arthrobacter sp. The single strain of Cor. aquaticum examined contained comparable amounts of menaquinones with 10 and 11 isoprene units whereas strains of Cor. mediolanum and Flavobacterium dehydrogenans contained major amounts of menaquinones with 11 and 12 isoprene units. The results of the present study indicate that lipid markers may be of considerable value in the classification and identification of 2, 4-diaminobutyric acid-containing phytopathogenic and saprophytic coryneform bacteria.

Lipids in the Classification and Identification of Coryneform Bacteria Containing Peptidoglycans Based on 2, 4-diaminobutyric Acid

A novel type of bacterium has been isolated from various geothermally heated locales on the sea floor. The organisms are strictly anaerobic, rod-shaped, fermentative, extremely thermophilic and grow between 55 and 90°C with an optimum of around 80°C. Cells show a unique sheath-like structure and monotrichous flagellation. By 16S rRNA sequencing they clearly belong to the eubacteria, although no close relationship to any known group could be detected. The majority of their lipids appear to be unique in structure among the eubacteria. Isolate MSB8 is described as Thermotoga maritima, representing the new genus Thermotoga.

Thermotoga maritima sp. nov. represents a new genus of unique extremely thermophilic eubacteria growing up to 90°C

Publisher Summary This chapter discusses the analysis of the chemical composition and primary structure of the murein. Murein (peptidoglycan, mucopeptide) is the main cell wall polymer of eubacteria and is common to both Gram-negative and Gram-positive bacteria. There are only a few prokaryotic organisms, such as mycoplasmas and archaebacteria, which lack murein. The glycan moiety is rather uniform and shows only a few variations such as O-acetylation or O-phosphorylation or the exceptional absence of peptide substituents. The peptide moiety of the murein shows, in contrast to the glycan part, a considerable variation. Extensive investigation of the chemical structure of murein has demonstrated the existence of almost 100 different variations of the peptide moiety. Depending on the mode of cross-linking two main groups of murein, named A and B, have been distinguished. The different structure of cell walls of Gram-positive and Gram-negative bacteria necessitates discrete methods for preparing cell walls. The cell walls of Gram-positive bacteria reveal in profile one thick and more or less homogeneous layer, whereas Gram-negative bacteria have thinner, but distinctly layered cell walls with an outer membrane resembling the cytoplasmic membrane in profile.

5 Analysis of the Chemical Composition and Primary Structure of Murein

Whole-cell hydrolysates were prepared from 58 strains of nocardiae and streptomycetes. Strains morphologically intermediate between the two genera and morphological variants of the same strains were included. Paper chromatograms made from the whole-cell hydrolysates clearly demonstrated meso-diaminopimelic acid as a major constituent of cultures of Nocardia spp., and LL-diaminopimelic acid as a major constituent of cultures of Streptomyces spp. In cultures of ten strains of N. madurae and of three of N. pelletieri, meso-diaminopimelic acid predominated, thereby supporting the assignment of these species to the genus Nocardia.

Rapid differentiation between nocardia and streptomyces by paper chromatography of whole-cell hydrolysates

The Behavior of the Isomers of α,ε-Diaminopimelic Acid on Paper Chromatograms

The stereoisomers of α∈-diaminopimelic acid. 2. Their distribution in the bacterial order Actinomycetales and in certain Eubacteriales

The stereoisomers of α∈-diaminopimelic acid. 3. Properties and distribution of diaminopimelic acid racemase, an enzyme causing interconversion of the ll and meso isomers

Interrelationships between lysine and α∈-diaminopimelic acid and their derivatives and analogues in mutants of Escherichia coli

ase-Diaminopimelic acid (1:5-diaminopentane-1:5dicarboxylic acid) is symmetrical about the ycarbon atom and contains two asymmetric centres; it has three stereoisomers, namely the LL, DD and meso (internally compensated) compounds. It appears to be confined to bacterial organisms and is widely distributed among them (Work & Dewey, 1953). Diaminopimelic acid was originally isolated from hydrolysates of Corynebacterium diphtheriae and Mycobacterium tuberculosi8, and the suggestion was made that it was the meao isomer because of its optical inactivity and its behaviour in the presence of the L-amino acid oxidase of Neuro8pora (Work, 1951). Subsequent evidence obtained with diaminopimelic acid decarboxylase supported this view (Work, 1953; Dewey, Hoare & Work, 1954), but rigorous proof could not be obtainedwithout a supply ofthe authentic meso isomer. Diaminopimelic acid has also been isolated from the culture filtrate of the lysine auxotroph E8cherichia coli 26-26 (Work & Denman, 1953; Wright & Cresson, 1953). Both groups of workers found that this diaminopimelic acid had a slight positive rotation when first crystallized, but after several recrystallizations it was optically inactive. Wright & Cresson suggested that some LL isomer was present in addition to the meso isomer. This paper describes the isolation from the mutant culture filtrate of a highly dextrorotatory compound which proved to be LL-diaminopimelic acid. The isomeric forms of all the naturally occurring diaminopimelic acids were established by direct comparison with the authentic isomers, made available by the resolution of synthetic diaminopimelic acid (Work, Birnbaum, Winitz & Greenstein, 1955). The enzymic decarboxylation, growth-promoting properties and natural distribution of the isomers have also been investigated. Preliminary reports of these results have already been given (Hoare, 1955; Hoare & Work, 1955 a). METHODS

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D. S. Hoare

Papers

The Behavior of the Isomers of α,ε-Diaminopimelic Acid on Paper Chromatograms

The stereoisomers of α∈-diaminopimelic acid. 2. Their distribution in the bacterial order Actinomycetales and in certain Eubacteriales

The stereoisomers of α∈-diaminopimelic acid. 3. Properties and distribution of diaminopimelic acid racemase, an enzyme causing interconversion of the ll and meso isomers

Interrelationships between lysine and α∈-diaminopimelic acid and their derivatives and analogues in mutants of Escherichia coli

The stereoisomers of α∈-diaminopimelic acid: their distribution in nature and behaviour towards certain enzyme preparations