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Essay Yersinia pestis - Bacteria Virulence and Symptoms

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Yersinia pestis - Bacteria Virulence and Symptoms

Yersinia pestis appeared fairly early in history and is still prevailing today. Humans have come in contact with this bacterium in massive outbreaks throughout history, including the most famous Black Death of the 14th century. From the lack of knowledge of the bacteria and its ability to infect populations rapidly, the human race has suffered immensely. The bacterium is specialized with specific plasmids, Yersinia outer proteins as well as other toxins that it uses to disrupt the body's immune response. Through this, Yersinia pestis avoids harm and effectively infects the circulatory system of its host causing three forms of the plague: Bubonic, Pneumonic and Septicemic. Each form of …show more content…

This rapidly deadly disease, characterized by these certain factors, enable the bacterium to eventually lead the host into a painful death. 2
The bacteria, Yersinia pestis, is encoded with two specific plasmids that aid in the transfer and survival of the bacteria, especially in the wild. Both of these plasmids must be present on the bacteria for full virulence of the organism. The largest of the extrachromosomal elements, with typical strains of ~100 kb, is the Murine toxin plasmid (pFra), a capsule protein. pFra is characterized by two specific factors: FI capsular protein antigen and YMT. The second plasmid, Pesticin plasmid named pPla after the plasminogen activator, happens to be the smallest of the plasmids. The bacteriocin (pesticin;Pst) and the bilanolysin and coagulase activities are found to be connected with one another and aids the former organism of Yersinia in the invasion of "the host from peripheral sites" (Carniel 41). After the bacteria is injected through a bite of the rat flea, Yersinia pestis affects the immune system similar to the bacterial agent, Bacillis anthracis. By having a Type III secretion system, the bacteria are able to find "a means ? to target virulence factors directly at host cells". The common Yersinia encoded plasmid molecule, pYV (or pLcr), found on the bacteria specifically aids in the injection of cytotoxic proteins into the macrophages, preventing the

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