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Mouse toxicity induced by lipids and cell walls isolated from actinomycetes
Abstract:
The possibility was examined that the toxicity induced in mice by Actinomadura madurae, 'Streptomyces pelletieri' and Nocardia brasiliensis was due to lipid and cell-wall constituents. Mice were inoculated intraperitoneally with heat-killed bacteria, lipid extracts and cell-wall preparations emulsified in mineral oil: toxicity was evaluated by recording weight loss and deaths. Killed cells and cell-wall preparations of all three actinomycetes produced a pronounced loss of body weight, tissue necrosis, splenomegaly, a granulomatous inflammation and sometimes death. Mice inoculated with lipid extracts from A. madurae and 'S. pelletieri' neither died nor showed toxic effects, but mice injected with lipids isolated from N. brasiliensis did suffer toxic effects. They showed more marked wasting symptoms than observed after inoculation of heat-killed bacteria or of the cell-wall preparation.
Insights
Lipid and cell-wall components of actinomycetes cause toxicity in mice. Nocardia brasiliensis lipids induced significant wasting, unlike other tested bacteria or their cell walls.
Area of Science:
- Microbiology
- Immunology
- Toxicology
Background:
- Actinomycetes, including Actinomadura madurae, 'Streptomyces pelletieri', and Nocardia brasiliensis, are known pathogens.
- The specific toxic components responsible for actinomycete-induced pathology in hosts are not fully elucidated.
Purpose of the Study:
- To investigate whether lipid and cell-wall constituents of A. madurae, 'S. pelletieri', and N. brasiliensis contribute to their toxicity in mice.
Main Methods:
- Mice were intraperitoneally inoculated with heat-killed bacteria, lipid extracts, and cell-wall preparations of the three actinomycetes, emulsified in mineral oil.
- Toxicity was assessed by monitoring weight loss, mortality, and pathological changes such as tissue necrosis and organomegaly.
Main Results:
- Heat-killed cells and cell-wall preparations from all three actinomycetes induced significant toxicity, including weight loss, necrosis, splenomegaly, granulomatous inflammation, and mortality.
- Lipid extracts from A. madurae and 'S. pelletieri' were non-toxic.
- Lipid extracts from N. brasiliensis induced severe wasting symptoms, exceeding the toxicity observed with its heat-killed cells or cell-wall preparations.
Conclusions:
- Cell-wall components of these actinomycetes are generally toxic.
- Lipids of N. brasiliensis are potent toxins, responsible for severe wasting, suggesting a key role in its pathogenicity.