Ta 1

Journal #4

Original article: http://www.scientificamerican.com/article.cfm?id=fungal-infection-accident-of-

evolution-may-thrive-in-our-bodies

Summarize: The article explains how fungus, an organism originally lived on plants, find its way to live inside human. The article starts with the case of Cryptococcus gattii, a fungus species used to live in soil and on trees. According to Karen Bartlett of the University of British Columbia, microorganisms like C.gattii constantly struggle for territory, food sources, and their place in microbial community. Also, they have to prevent themselves from amoebic annihilating by their predators, mainly amoebas. In order to do so, many mechanisms have been evolved on Cryptococcus species to hide their would-be predators. Those mechanisms also work on human immune cells because they share evolutionary roots with free-living amoebas. Due to this, C.gattii can kill our immune cells and may use them as a Trojan horse to travel through the body. Another case is Legionella pneumophilia, which causes Legionnaires' disease, living inside wild aquatic amoebas and similarly mistakenly infects human immune cells when victims inhale it. As Arturo Casadevall says, “Virulence is not their business. Their business is survival. But the same pressures that are allowing them to survive results in traits that gives them capacity to survive in mammals.”

This article enhances my understanding of biological issue by providing me some useful information about how fungi, organisms living in soil and on trees can thrive in our body and cause deadly diseases. I also know that amoebas are their big predators, and our immune cells share evolutionary roots with free-living amoebas.

For general public, this article is important because many fungi like C.gatti can cause fatal diseases when they get into our body due to their ability to hide from immune cells. Because of this, we should put more efforts on studying fungi in order to prevent many diseases in the future.