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Mycobacterium tuberculosis complex DNA was isolated and identified in calcified pleura from remains 1400 years old, with the polymerase chain reaction. This is the first demonstration of tuberculosis in non-mummified archaeological tissue other than bone; the presence of mycobacterial mycolic acids in the sample supports this conclusion. The study of ancient DNA from microbial pathogens is of interest as it enables verification of traditional diagnoses, may answer long-standing questions in the history of disease, and provides ancient DNA sequences that can be compared with those of modern isolates.

[ 14 C]acetate was incorporated into mycolic acids by a cell-free, cell-wall fraction from Mycobacterium smegmatis. This activity was inhibited by methyl 4-(2-octadecylcyclopropen-1-yl) butanoate which was designed as a structural analogue of cis-tetracos-5-enoate, a precursor of mycolic acid biosynthesis. Other fatty acids and their methyl esters failed to inhibit mycolic acid biosynthesis at the concentration 1-2 mg ml −1 , at which methyl 4-(2-octadecylcyclopropen-1-yl) butanoate was effective. Thus a novel agent was shown to act against an enzyme activity or target involved specifically in biosynthesis of a characteristic, mycobacterial, cell-wall component

A characteristic phenolic glycolipid was detected, by thin layer chromatography, in non-polar lipid extracts of nine representative strains of Mycobacterium haemophilum. The lipid was a specific antigen that reacted strongly with serum raised against whole cells of M. haemophilum. Sera from six other mycobacterial strains were tested but only that from Mycobacterium kansasii give a weak reaction.

Diacyl phthiodiolone A and phenolphthiodio-lone A lipids were isolated from two strains of Mycobacterium ulcerans . The diol units of the phthiodiolone A and phenolphthiodiolone A components were shown to have erythro stereochemistry by infrared spectroscopy and proton nuclear magnetic resonance of an acetal derivative. This stereochemistry is shared only by related diols from M. marinum , the diols from M. bovis, M kansasu, M leprae and M. tuberculosis having threo stereochemistry.

1. INTRODUCTION 2. MATERIALS AND METHODS Since the early work of Cummins and Harris [1] cell wall analysis has become a widely used tech- nique in both the classification and identification of Gram-positive bacteria [2]. Methods for de- termining wall amino acids include paper chro- matography, thin-layer chromatography (TLC) and ion exchange chromatography using the amino acid analyser; the latter being the method of choice where quantitative data are required [3]. Paper chromatography and TLC have been used prim- arily to provide a rapid qualitative assessment of the wall amino acid composition and to detect diagnostic diamino acids [4,5]. An established technique, applied only rarely to bacterial amino acids [6,7], is the conversion of amino acids into volatile derivatives and their analysis by gas chro- matography (GC) [8]. This approach is of poten- tial value since it provides reliable quantitative data on wall amino acids without the use of an amino acid analyser. This paper reports on the application of GC to the analysis of wall amino acids from selected defatted actinomycetes.

Preparations of Mycobacterium leprae, purified from host animal tissues, were screened by pyrolysis high-resolution gas-chromatographic analysis (Py-GC) for the presence of (myco)bacterial contaminants, which produce wax-ester mycolates. Contamination levels as low as 5% of the total number of acid-fast bacilli could be detected, based on the presence or absence of the marker compounds: a series of isomeric alkenes. The on-line pyrolysis capillary GC method provides an easy procedure for rapid quality control of preparations of purified M. leprae.

An immunostaining method is described for the direct detection of mycobacterial lipid antigens on thin-layer chromatograms, no prior purification of the crude lipid extract is required. Analysis of Mycobacterium scrofulaceum serovar 41 gave positive reactions for the polar, but not the non-polar, glycopeptidolipids, with an antiserum against whole cells of the same strain. The family of phosphatidylinositol mannosides did not react with this antiserum but a reaction was obtained with an antiserum against intracellular material from another strain.

Lipids were extracted from small skin biopsies obtained from 5 lepromatous leprosy patients by employing a procedure designed to produce separate non-polar and polar fractions. The defatted tissue was subjected to alkaline hydrolysis and the total fatty acids in the hydrolysate were converted to methyl esters by a phase transfer reaction using iodomethane. The composition of free lipids and methyl esters of fatty acids was analysed by special thin-layer chromatographic systems. The presence of dimycocerosates of phthiocerol A, phthiocerol B and phthiodiolone A, phenolic glycolipid-I, two phosphatidyl inositol mannosides and 2 mycolates − alpha- and keto-mycolate − was demonstrated using reference lipid samples.

Free lipids were extracted from Mycobacterium tuberculosis H37Rv, and their antigenicity was assessed directly on thin-layer chromatograms (TLC) by an immunostaining technique. A family of glycolipids, composed of trehalose acylated with multimethyl branched long-chain fatty acids, was investigated. The most polar of these glycolipids was identified as a possible specific surface antigen. A pair of novel polar glycolipids also showed positive antigenic reactions.