Bacillus Subtilis Research Paper
2. Description of non-pathogen:
B. subtilis is a mesophilic, gram-positive bacillus that is commonly found in soil, although it can also survive in plants (1). B. subtilis are facultative aerobes, using butanediol fermentation or nitrated ammonification when oxygen is unavailable (1). The bacillus is motile by using a single flagellum and commonly forms biofilms which contain several B. subtilis all traveling in the same direction (1). It has a circular DNA chromosome that contains 4,185 protein sequences, with a total of 4,215,606 base pairs, and no additional plasmids (2). B. subtilis can form endospores that provide some heat, chemical, and radiation resistance to the bacterium, and these spores …show more content…
One possible scenario for the transfer of the toxin-coregulated pilus to B. subtilis is the fertilization of crops using human waste. Waste contaminated with V. cholerae cells could be used to fertilize crops that have B. subtilis growing on their roots, acting as an anti-fungal. Since V. cholerae are gram-negative, they would be unable to produce a spore in the event of a lack of resources, leading to the lysis of the cells. This would release the genetic material of V. cholerae, perhaps with the vibrio pathogenicity island containing the genetic code for the TCP intact. B. subtilis could then integrate the genetic code for the toxin-coregulated pilus into its own chromosome by bacterial transformation. Since the genetic code for the toxin-coregulated pilus also contains code for a surface receptor, this could also result in the infection of B. subtilis by the same lysogenic bacteriophage that produces the cholera toxin (7). This would increase the pathogenicity of B. subtilis further, as it would produce more …show more content…
cholerae, Shigella dysenteriae is also found in the waste of those infected. If this infected waste were used to fertilize plants that were colonized by B. subtilis, a similar situation could develop, as S. dysenteriae is also gram-negative and would be unable to survive harsher conditions than B. subtilis. When the S. dysenteriae lyses, it could release the genes encoding the A subunit and the five B subunits of the Shiga toxin, which could be added to the chromosome of B. subtilis by bacterial transformation (7).
Due to the conditions required for the transfer of these pathogenicity factors, the evolution of B. subtilis to this particular pathogenic state is likely to occur in an economically weak, rural area.
5. Pathogenicity (remember it doesn’t need to be good at everything):
Enters through the ingestion of contaminated water, soil, or plants as a spore.
Uses the TCP acquired from V. Cholerae to attach to intestinal mucosal cells.
Forms a biofilm along the intestinal wall, clearing nearby cilia and producing antibiotics that will kill nearby competing bacteria.
The polysaccharide capsule obtained from B. Anthracis prevents engulfment by macrophages as well as preventing opsonization of the bacterium.