Limits...
Anthrolysin O and fermentation products mediate the toxicity of Bacillus anthracis to lung epithelial cells under microaerobic conditions.

Popova TG, Millis B, Chung MC, Bailey C, Popov SG - FEMS Immunol. Med. Microbiol. (2010)

Bottom Line: Human small airway epithelial, umbilical vein endothelial, Caco-2, and Hep-G2 cells were found to be susceptible.Its effect was found to be synergistic with a metabolic product of B. anthracis, succinic acid.Cell death appears to be caused by an acute primary membrane permeabilization by ALO, followed by a burst of reactive radicals from the mitochondria fuelled by the succinate, which is generated by bacteria in the hypoxic environment.

View Article: PubMed Central - PubMed

Affiliation: National Center for Biodefense and Infectious Diseases, George Mason University, Manassas, VA, USA.

Show MeSH

Related in: MedlinePlus

The microaerobic growth of Bacillus anthracis under different culture conditions. (a) Static cultures grown at 37°C, 5% CO2 in the nitrate-rich CSFM (triangles), Luria broth (circles), DMEM/F-12 (squares), and DMEM/F-12 supplemented with 300 μM NaNO3 and 1 μg mL−1 of BSA (diamonds) generate acidic and toxic Sups. Open symbols, dSterne; closed symbols, Sterne 34F2. (b and c) Aeration by shaking at 200 r.p.m. of the B. anthracis cultures grown at 37°C, 5% CO2 in CSFM reduces the toxicity and acidification of Sups (b) and abrogates the consumption of nitrate from the medium (c). The final pH or the cultures is shown in (b). Error bars represent 95% confidence interval of mean.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3040846&req=5

fig02: The microaerobic growth of Bacillus anthracis under different culture conditions. (a) Static cultures grown at 37°C, 5% CO2 in the nitrate-rich CSFM (triangles), Luria broth (circles), DMEM/F-12 (squares), and DMEM/F-12 supplemented with 300 μM NaNO3 and 1 μg mL−1 of BSA (diamonds) generate acidic and toxic Sups. Open symbols, dSterne; closed symbols, Sterne 34F2. (b and c) Aeration by shaking at 200 r.p.m. of the B. anthracis cultures grown at 37°C, 5% CO2 in CSFM reduces the toxicity and acidification of Sups (b) and abrogates the consumption of nitrate from the medium (c). The final pH or the cultures is shown in (b). Error bars represent 95% confidence interval of mean.

Mentions: Comparison of Sups generated in different media showed that the highest toxicity was detected in the case of bacteria grown in the CSFM medium, in contrast to DMEM/F-12 and Luria broth (Fig. 2a, lower panels). We noticed that CSFM contains a high amount of nitrate (∼300 μM in CSFM vs. <1 μM in DMEM/F-12) and suggested that it may play a role in toxicity through changes in bacterial metabolism. Nitrate is known to replace oxygen for bacterial respiration under microaerobic (reduced oxygen) conditions present in static bacterial cultures (Hassett, 1996; Wyckoff et al., 2002; Ju et al., 2005; Pettersen et al., 2005;). The resulting process of denitrification (Ju et al., 2005; Rock et al., 2005;) can lead to the consumption of nitrate. Indeed, microaerobic cultivation of B. anthracis in CSFM under static conditions was accompanied by a reduction in the nitrate content (Fig. 2b) and acidification of the medium to pH 5.3–5.5 (Fig. 2a, middle panels), indicating anaerobic acid fermentation.


Anthrolysin O and fermentation products mediate the toxicity of Bacillus anthracis to lung epithelial cells under microaerobic conditions.

Popova TG, Millis B, Chung MC, Bailey C, Popov SG - FEMS Immunol. Med. Microbiol. (2010)

The microaerobic growth of Bacillus anthracis under different culture conditions. (a) Static cultures grown at 37°C, 5% CO2 in the nitrate-rich CSFM (triangles), Luria broth (circles), DMEM/F-12 (squares), and DMEM/F-12 supplemented with 300 μM NaNO3 and 1 μg mL−1 of BSA (diamonds) generate acidic and toxic Sups. Open symbols, dSterne; closed symbols, Sterne 34F2. (b and c) Aeration by shaking at 200 r.p.m. of the B. anthracis cultures grown at 37°C, 5% CO2 in CSFM reduces the toxicity and acidification of Sups (b) and abrogates the consumption of nitrate from the medium (c). The final pH or the cultures is shown in (b). Error bars represent 95% confidence interval of mean.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3040846&req=5

fig02: The microaerobic growth of Bacillus anthracis under different culture conditions. (a) Static cultures grown at 37°C, 5% CO2 in the nitrate-rich CSFM (triangles), Luria broth (circles), DMEM/F-12 (squares), and DMEM/F-12 supplemented with 300 μM NaNO3 and 1 μg mL−1 of BSA (diamonds) generate acidic and toxic Sups. Open symbols, dSterne; closed symbols, Sterne 34F2. (b and c) Aeration by shaking at 200 r.p.m. of the B. anthracis cultures grown at 37°C, 5% CO2 in CSFM reduces the toxicity and acidification of Sups (b) and abrogates the consumption of nitrate from the medium (c). The final pH or the cultures is shown in (b). Error bars represent 95% confidence interval of mean.
Mentions: Comparison of Sups generated in different media showed that the highest toxicity was detected in the case of bacteria grown in the CSFM medium, in contrast to DMEM/F-12 and Luria broth (Fig. 2a, lower panels). We noticed that CSFM contains a high amount of nitrate (∼300 μM in CSFM vs. <1 μM in DMEM/F-12) and suggested that it may play a role in toxicity through changes in bacterial metabolism. Nitrate is known to replace oxygen for bacterial respiration under microaerobic (reduced oxygen) conditions present in static bacterial cultures (Hassett, 1996; Wyckoff et al., 2002; Ju et al., 2005; Pettersen et al., 2005;). The resulting process of denitrification (Ju et al., 2005; Rock et al., 2005;) can lead to the consumption of nitrate. Indeed, microaerobic cultivation of B. anthracis in CSFM under static conditions was accompanied by a reduction in the nitrate content (Fig. 2b) and acidification of the medium to pH 5.3–5.5 (Fig. 2a, middle panels), indicating anaerobic acid fermentation.

Bottom Line: Human small airway epithelial, umbilical vein endothelial, Caco-2, and Hep-G2 cells were found to be susceptible.Its effect was found to be synergistic with a metabolic product of B. anthracis, succinic acid.Cell death appears to be caused by an acute primary membrane permeabilization by ALO, followed by a burst of reactive radicals from the mitochondria fuelled by the succinate, which is generated by bacteria in the hypoxic environment.

View Article: PubMed Central - PubMed

Affiliation: National Center for Biodefense and Infectious Diseases, George Mason University, Manassas, VA, USA.

Show MeSH
Related in: MedlinePlus