Escherichia coli

Escherichia coli is a species of bacteria (E. coli). Although E. coli are often harmless, and in fact beneficial, infections can cause disease. Urinary tract infections, respiratory illness and pneumonia, and others, are at times due to E. coli. They are used as markers for water contamination. But if you hear of E. coli being found in drinking water do not be alarmed, they are not themselves harmful, but indicate the water is contaminated.

The genus was discovered by a man named Theodor Escherisch (hence the name Escherichia). Theodor was a pediatrician in the late 1800's and isolated the bacteria from feces, but it wasn't until 1935 that E. coli was determined to be the cause of diarrhea in newborns.

Anatomy


E. coli is a single-celled organism that moves about with it's multiple flagellum. The chromosome of the E. Coli cell has DNA about 700 times longer than the body itself. Most of the 4,288 genes within this cell can code different kinds of proteins. Out of all of those genes, only 62% actually have a function. About 50 different kinds of proteins are required to produce the cell’s chemotaxis (movement in reaction to a chemical stimulus), roughly half for the assembly of flagella and half for behavioral control. In about 20 minutes or so, in a favorable environment, it can duplicate itself into another cell. Even though this cell seems to only live in the intestines of animals and humans, it can also survive in many different types of enivornments.

Reproduction
This bacteria, E. coli, reproduces asexually and duplicates itself almost exactly. The cell first begins to grow, by length, not by width. After it grows by length, it will make a replica of its genome. Sometimes small mistakes can be made within this replication, but none big enough to affect the reproduction process. E. coli actually reproduces every twenty minutes! Symmetry is key in the process of division. Also, this bacteria ages as it goes through the process of division. When the older cell separates from the newer daughter cell, its growth rate can drop and it can now die much more quickly. There is also another less common way that these cells can reproduce. It's by conjugation. Genetics can actually be passed from one E. coli cell to another. This is definitely not considered sexual reproduction because there are no gametes included in this process. One of these bacteria produces a genome, and this genome will be placed in the other bacteria. Then, an enzyme will release, as if calling for a mate. This bacteria that set off the enzyme has the genome and is F+. This enzyme will search for another E. coli bacteria that doesn't contain it, so that bacteria is called F-. The F+ bacteria connects to the F- bacteria and will transfer its information to the other, and the process is finished. 

Ecology
Escherichia coli can be found in both humans and animals. It lives it the intestines of most people and animals that carry the bacteria. E. coli can actually live in a healthy cow, but then when the cow is slaughtered, the bacteria can transcend. Raw milk, fresh vegetables, and unpasteurized drinks can cause an outbreak of this bacteria in a human. In children under five years old, this bacteria can kill the red blood cells and destroy their kidneys. This bacteria reproduce optimally at 37 degrees Celsius. 

The E. coli bacteria cell is a heterotrophic feeder (meaning that it gets its food from some other source) and greatly depends on carbon compounds for energy. They get these energy carrying compounds from the hosts that they live in. These metabolites are broken down into a usable form for the bacteria by its central metabolism. High ATP levels are also assuring for E. coli because it needs high energy for its metabolic rate. Escherichia coli can react with the environment in diverse ways. It can react with things like temperatures, pH levels, and other things. It has amazing receptors that can tell it whether to swim towards something it should be, or to swim away from it. 

E. coli 0157:H7
This type of E. coli affects a person's intestinal tract. E. coli 0157:H7 can also affect other parts of your body if there is an outbreak. This bacterial infection is contagious, and can cause outbreaks within areas. These infections are seen more in the summer months. This outbreak can cause bloody diarrhea and abdominal cramps. Sometimes a slight fever can occur. The symptoms of bloody diarrhea and abdominal cramps can last about three to four days. There are two serious outcomes that can occur if you having this infection. A person could get HUS or TTP. HUS stands for hemolytic-uremic syndrome. This can enter the blood stream and destroy important red blood cells. TTP stands for thrombotic thrombocytopenic purpura. TTP can cause kidney failure and neurologic abnormalities.