Cell Wall of Mycobacterium lepraemurium Strain Hawaii

Abstract

The chemical properties of the cell wall of Mycobacterium lepraemurium strain Hawaii were investigated. Five subunits of the cell wall, arabinose mycolate, mycolic acids, tetrapeptide (Ala-Gln-diaminopimelic acid-Ala), disaccharide (N-acetylglucosaminyl.B-1,4-N-glycolylmuramic acid), and arabinogalactan, were obtained, and their chemical structures were identified.It is well known that Mycobacterium lepraemurium is the causative microorganism of murine leprosy, a chronic infection in the rat and the mouse. Its taxonomy has not yet been established. Uyeda (18,19) claimed that, from the morphological features of this bacillus, it should not be classified as a mycobacterium, but rather should be placed in a new genus related to nocardia. However, results of recent works on the chemical analysis of the M. lepraemurium cell wall (7-9, 14) suggest that its chemical composition qualitatively resembles that of the cell walls of mycobacteria (15). Also, Fukui and co-workers (12) have reported that the crude extracts of eight strains of M. lepraemurium contain a cross-reactive material whose antigenic determinants are partially in common with an alpha antigen of Mycobacterium avium. This finding also suggests the propriety of the serological typing of M. lepraemurium as a Mycobacterium.In this study, the chemical and immunological properties of the cell wall and polysaccharides of M. lepraemurium strain Hawaii have been examined in detail, and, based on these properties, it has been concluded that this microorganism is a Mycobacterium.Collection and fractionation of cells. A 0.2-ml portion of an emulsion of M. lepraemurium Hawaii leproma, diluted 1,000 times with Hanks solution, was inoculated subcutaneously into 400 4-week-old C3H mice. Six months later, the lepromas were excised and homogenized, and the M. lepraemurium Hawaii cells were collected by differential cen-' Present address: Rocky Mountain Laboratory, National

Mycobacterial antigens: a review of their isolation, chemistry, and immunological properties.

“…Kotani and his co-workers reported similar observations with arabinose-rich polysaccharides and polysaccharide-glycopeptide complexes obtained from M. tuberculosis cell walls by enzymatic digestion (116). The arabinogalactans and arabinomannans studied by 17,[205][206][207] were also capable of eliciting immediate skin reactions, serological reactions, and passive cutaneous anaphylaxis, but they were incapable of eliciting delayed skin test reactions. Polysaccharide antigens isolated by Wayne from M. kana-sasii, M. gastri, and M. marinum by extraction with phenol, methanol, and acetone were found to react in immunodiffusion systems with antisera, and antigens were shared among the three species (199).…”

De Novo Design of Selective Antibiotic Peptides by Incorporation of Unnatural Amino Acids

“…These differences are in part responsible for the observed selectivity of some AMPs for bacterial vs mammalian cells. , In addition to the differences between eukaryotic and prokaryotic cells, the membranes surrounding different types of bacteria are also different. The lipid bilayer of Gram positive bacteria is covered by a porous layer of peptidoglycan, while the structure of Gram negative bacteria is more complex with two lipid membranes containing lipopolysaccharides and porins. , The outer membrane of mycobacteria is the most complex consisting of a very thick mycolate-rich outer coat that is very difficult to penetrate. There is a developing preponderance of evidence in the literature supporting the concept that the selectivity and potency of a specific AMP are determined in a large measure by the chemical composition of the target membrane. , Thus, it is reasonable to postulate that the membrane's physicochemical surface interactions with the physicochemical surface of the AMP define organism selectivity. ,,, The hypothesis guiding our research was developed from this observation.…”

“…The lipid bilayer of Gram positive bacteria is covered by a porous layer of peptidoglycan, while the structure of Gram negative bacteria is more complex with two lipid membranes containing lipopolysaccharides and porins. 2,25 The outer membrane of mycobacteria is the most complex consisting of a very thick mycolate-rich outer coat 26 that is very difficult to penetrate. There is a developing preponderance of evidence in the literature supporting the concept that the selectivity and potency of a specific AMP are determined in a large measure by the chemical composition of the target membrane.…”

Application of 3D-QSAR for Identification of Descriptors Defining Bioactivity of Antimicrobial Peptides

“…We have extended this rationale to explain the observed differences in organism selectivity and potency for various bacterial strains as well. It is well-known that the chemical compositions of the membranes of different bacterial strains vary. ,, Because the chemical compositions of the membranes of different bacterial strains vary greatly, the resulting physicochemical surface properties presented by the membrane to the external environment will therefore be different as well as specific for each type of bacterial strain. Our guiding hypothesis evolved from the above assertion, which in its simplest form states the following: the 3D-physicochemical surface properties of target cell membrane (bacterial or mammalian) interact with the 3D-physicochemical surface properties of the approaching AMP in a very specific way (via bioactive conformation), thus defining the resulting organism selectivity and potency.…”