Mycobacterial polysaccharides. II. Comparison of polysaccharides from strains of four species of mycobacteria

Polysaccharides of Mycobacterium bovis Ushi 10, Mycobacterium smegmatis, Mycobacterium phlei, and Atypical Mycobacterium P1

Four kinds of polysaccharides, glucan, mannan, arabinomannan, and arabinogalactan, were purified from the defatted cells of four strains of mycobacteria. By the chemical and immunological analyses, we concluded that arabinomannan and arabinogalactan are common serologically active polysaccharides in mycobacteria.

Phenol-Soluble Antigens from Mycobacterium kansasii, Mycobacterium gastri, and Mycobacterium marinum

Many of the demonstrable antigens derived from mycobacteria are common to members of different species. Agglutination tests have yielded the most specific characterizations. An antigen which may be associated with the specific agglutination is soluble in phenol and can be extracted and separated from other antigens by use of this solvent. Phenol-soluble antigens have been extracted from representative cultures of Mycobacterium kansasii, M. gastri, and M. marinum. Most representatives of each of these species yielded an antigen which was characteristic of the species but was distinct from antigen derived from the other two species.

Studies on the antigenic specificity of Mycobacterium leprae. I. Isoelectric and chromatofocusing separation

Cell sonicates of Mycobacterium leprae and other mycobacteria were subjected to isoelectric focusing and chromatofocusing to evaluate their protein antigens and to determine if the patterns were significantly different. Isoelectric focusing showed that the proteins of all mycobacteria focused within the pH range of 3.5 to 5.5, except those of M. leprae which extended beyond 5.5 to 6.5. These studies have indicated for the first time that the protein antigens of mycobacteria are acidic in nature. Comparison between the proteins of untreated and autoclaved M. leprae showed distinct differences between the two preparations, in respect of loss of some antigens in the autoclaved M. leprae sonicate. This indicates that the bands that were not visible in the autoclaved M. leprae were those of heat-labile proteins. It is possible, however, that the absent bands could have been of a low order of intensity and hence were not discernible. On the other hand, the proteins could have coagulated due to the heat treatment, thus causing confirmational changes or ionic interactions with membrane components, due to their acidic nature. It is possible that the proteins in the autoclaved M. leprae are the ones that possess immunogenic properties since the protective ability of heat-killed M. leprae has already been established. Chromatofocusing studies have confirmed the isoelectric focusing data in respect of the number of antigens and their respective protein content, besides permitting the availability of the various fractions for further biological characterization.

Adhesion of a Mycobacterium sp. to cellulose diacetate membranes used in reverse osmosis

The kinetics of adhesion of a Mycobacterium sp. to cellulose diacetate reverse-osmosis membranes is described. This Mycobacterium sp. (strain BT2-4) was previously implicated in the initial stages of reverse-osmosis membrane biofouling at a wastewater reclamation facility. Adhesion of BT2-4 cells to the cellulose diacetate membrane surfaces occurred within 1 to 2 h at 30 degrees C and exhibited saturation-type kinetics which conformed closely to the Langmuir adsorption isotherm (Pearson r correlation coefficient = 0.977), a mathematical expression describing the partitioning of substances between a solution and solid-liquid interface. This suggests that the cellulose diacetate membrane surfaces may possess a finite number of available binding sites to which the mycobacteria can adhere. Treatment of the attached mycobacteria with different enzymes suggested that cell surface polypeptides, alpha-1, 4- or alpha-1,6-linked glucan polymers, and carboxyl ester bond-containing substances (possibly peptidoglycolipids) may be involved in mycobacterial adhesion. The possible implication of these findings for reverse-osmosis membrane biofouling are discussed.

Structural and immunochemical characterization of the acidic arabinomannan of Mycobacterium smegmatis

A serologically active, acidic arabinomannan has been isolated from Mycobacterium smegmatis. The polysaccharide contains approximately 56 arabinosyl and 11 mannosyl residues, and 2 phosphate, 6 monoesterified succinate, and 4 ether-linked lactate groups. After saponification to remove succinyl groups, the polysaccharide can be separated into phosphorylated (55%) and nonphosphorylated (45%) forms, the former containing a little more arabinose and a little less mannose than the latter. The structures of these polysaccharides were investigated by 1H- and 13C-n.m.r. spectroscopy and methylation analysis, before and after selective cleavage of furanosyl linkages. The phosphorylated and nonphosphorylated forms of the polysaccharide were found to have similar, if not identical, structures. The main structural feature of the polysaccharides is the presence of chains of contiguous arabinofuranosyl residues linked alpha-(1 leads to 5). These chains are attached at 0-4 of arabinopyranosyl residues that are present in a core region of the polysaccharide that also contains mannopyranosyl residues. Immunochemical studies demonstrated that the polysaccharide is an effective, precipitating antigen with antisera from rabbits immunized with cell walls or heat-killed cells of M. smegmatis. The polysaccharide is, however, more effective as a precipitating antigen after removal of the succinate groups, and completely ineffective after removal of arabinofuranosyl residues. The polysaccharide therefore contains an important antigen in common with the arabinogalactan lipopolysaccharide of the cell wall of the bacterium, i.e., chains of contiguous alpha-(1 leads to 5)-linked arabinofuranosyl residues.

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

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