The human body produces more cells that it needs, and the surplus cells that do not serve any function are expelled so that the useful cells can work efficiently. This is the basic foundation of human anatomy.
The removal process of the cells is known as apoptosis. It is the body’s way of eliminating cells and it is done by instructing the cell to kill itself. Yes, it sounds a bit dark, but it is also a very efficient way of removing cells from the body without adding any complications.
But scientists did not know how fast that information traveled through a cell. We did not know how much time it took for the cell to eliminate itself and how the information traveled across the cell.
To understand and find the answers to these elusive questions, biologists from Stanford University School of Medicine Xianrui Cheng and James Farrell Jr got to work.
Using Frog Eggs to Figure Out Apoptosis
They studied the cells to figure out the methods they use to transfer information. In apoptosis, the death of cells occurs through the action of proteins called Caspases.
These proteins affect the nearby molecules, breaking them up again, releasing more Caspases in the process. And this process continues ad infinitum.
To study precisely how this phenomenon works, scientists tested a programmed cell death on frog eggs. They used the cytoplasm or the cell material in the frog eggs and isolated them in a test tube.
They further introduced a part of the cytoplasm to cells that had undergone an apoptosis. The scientist then dyed the cytoplasms to have a detailed look at the speed at which the cell died.
The results were quite amazing. It was found that the information transfer that happens inside a cell as a result of protein activation propagates like a wave.
As Caspases are produced at one point in the cell, it results in the breaking up of the nearby molecule, releasing more Caspases. With further increase in the concentration of Caspases, the nearby molecules deteriorate and continue the destruction in a constant manner.
"It spreads in this fashion and never slows down, never peters out," James Ferrell, the study author and a professor of chemical and systems biology and of biochemistry at Stanford University, said in a statement. "It doesn't get any lower in amplitude because every step of the way it's generating its own impetus by converting more inactive molecules to active molecules until apoptosis has spread to every nook and cranny of the cell."
Clocking the Speed of Cellular Suicide
The researchers call the pattern “trigger waves” which propagate through a cell causing destruction in their path. They are also comparing the destruction to the pattern of dominos falling.
As long as the proteins and death signal chemicals are available, the destruction continues without any halt. Scientists found that the rate of this destruction is 30 micrometers per minute, which is pretty quick considering the size of cells.
Apoptosis is a process that occurs within our body at every second of our life. Thought it might sound dark, the absence of apoptosis causes diseases such as cancer. This shows how complex and equally fascinating the human body is!
The study was published in Science August 10.
Via: Stanford Medicine