This week in AP Bio we began working on signaling. We started off with bacteria (may have been last week, I forget), then how insulin effects diabetes, and we finished off with cellular respiration.
To learn about bacteria signaling we watched a Ted video which was interesting, but it was also pretty scary to learn about. We learned about how some organisms use signaling to their advantage such as the Hawaiian bobtail squid. The Squid uses the signaling in Vibrio Ficheri (a bacteria) to mirror the exact amount of light the moon shines through the water, this way the animal casts no shadow which helps it not only to hunt, but avoid being hunted. For years in the summer, I have gone to the dock late at night and jumped in with friends or threw rocks in just to see the green glow of the bioluminescence. What the lady in the Ted video explained is that if you had only one bacteria cell or even just a few, you would see no glow. It is when they are all together they are able to communicate to each other, which is what creates the beautiful glow. All bacteria known to man communicate in the same way; they can send signals out, and they can receive them. Most of the time, the signal will just float away, nothing will happen with it. But in a group, there are a ton of signals floating around as well as more receptors so the signaling is much more effective.
The communication is really cool to see visually, and is even a survival mechanism for some animals. Bacteria are good because they keep us alive, they digest food and they give us a protective barrier. Why they are bad is because of quorum sensing. Quorum sensing is basically a vote for bacteria, it allows them to count and to plan a synchronized attack on the host. For a large host such as a human, if bacteria were to attack with few numbers or not all at once, our immune system would wipe them out. On the other hand, if the bacteria attack all at once, they may be able to quickly kill the host before they recover. (this is why you can get sick over night). What makes the bacteria even worse is what was recently discovered. Bacteria have a universal language and can talk to other bacteria which is very bad news for both the host, and for medical treatment.