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Toxin production by Bacillus pumilus
1Department of Pathological Sciences, University of Manchester.
Abstract:
Two strains of Bacillus pumilus (M11 and M38) and one strain each of Bacillus cereus (M27), Bacillus subtilis (M67), and Enterobacter agglomerans (M14) were identified from the air of Lancashire cotton mills. These strains were tested for cytopathic effects in Vero cells; B pumilus and B cereus strains were also examined for haemolytic activity, lecithinase production, and proteolytic action on casein. Rounding and clumping of the Vero cells occurred after the addition of supernatants prepared from B pumilus and B cereus strains; finger-like projections developed in the cells treated with B pumilus supernatants. Minimal effects occurred with B subtilis and E agglomerans. After two hours of exposure B pumilus (M11) produced the greatest effect, but treatment with trypan blue showed that most cells exposed to the M11 strain were still alive after 96 hours of exposure; those exposed to the supernatant prepared from the M38 strain of B pumilus were dead. Sheep erythrocytes were lysed more rapidly by B cereus than by B pumilus, B cereus (strongly positive) had a greater effect on lecithin than either of the B pumilus strains (M38 weakly positive, M11 negative). All hydrolised casein but the effect was more rapid with one of the B pumilus (M11) strains. It is concluded that not only do the toxins of B pumilus differ from those of B cereus, but there are also differences between the toxins produced by the two strains of B pumilus (M11 and M38).
Insights
Bacterial toxins from Bacillus pumilus and Bacillus cereus strains found in cotton mills exhibit distinct cytopathic effects. Differences in toxin activity were observed even between two Bacillus pumilus strains.
Area of Science:
- Microbiology
- Environmental Health
- Toxicology
Background:
- Air samples from Lancashire cotton mills yielded Bacillus pumilus (M11, M38), Bacillus cereus (M27), Bacillus subtilis (M67), and Enterobacter agglomerans (M14).
- These airborne bacteria may pose risks in occupational settings.
Purpose of the Study:
- To investigate the cytopathic effects and toxicological profiles of bacterial strains isolated from cotton mill air.
- To compare the toxic activities of Bacillus pumilus and Bacillus cereus.
Main Methods:
- Bacterial strains were cultured, and their supernatants were applied to Vero cells to assess cytopathic effects.
- Haemolytic activity, lecithinase production, and caseinolytic activity were evaluated for B. pumilus and B. cereus strains.
Main Results:
- Supernatants from B. pumilus and B. cereus induced cell rounding, clumping, and, in the case of B. pumilus, finger-like projections.
- B. pumilus (M11) showed rapid cytopathic effects, but M38 induced cell death within 96 hours.
- B. cereus exhibited stronger haemolytic and lecithinase activity than B. pumilus strains, while both hydrolyzed casein.
Conclusions:
- Bacterial toxins from B. pumilus and B. cereus differ significantly in their activity.
- Distinct toxicological profiles were identified even between the two B. pumilus strains (M11 and M38).