Peter Setlow, Professor of Molecular, Microbial and Structural Biology at the University of Connecticut Health Center in Farmington, CT, authors a guest post on Small Things Considered in which he ponders the reasons why silicon is present on some Bacillus spores and what could possibly be the benefit of this attribute.
"Amid the furor surrounding the anthrax attacks in the USA in 2001, significant attention was focused on whether the Bacillus anthracis spores used had been “weaponized” by the adding of a coating of fumed silica to aid in their dispersal. This information might have helped pinpoint where the spores had originated. However, a confusing factor was that for more than 20 years, significant levels of silicon had been reported in spores of at least some Bacillus species, including those of Bacillus cereus, a close relative of B. anthracis. Clearly, the natural presence of silicon in B. anthracis spores makes discrimination between weaponized and non-weaponized spores more difficult. However, in the older reports the silicon was not localized at the outermost surface of the spores, as would be expected if they had been artificially spiked with such compounds.
Anyhow, what is silicon doing on a bacterial spore?"