The roles that bioluminescence plays in the lives of organisms today is fascinating. How did this trait evolve? This is a complex question, because bioluminescence is believed to have evolved around 50 different times in different species of animals.
So how do living creatures produce light? Well, the actual question that needs to be asked is how do living creatures produce visiblelight.
Streptococcus pyogenes (I'll call it strep for short) is one of many pathogenic bacteria which are known to colonise the respiratory tract. as a result it causes the disease known as strep throat, and another known as scarlet fever. If you are lucky, it gets confined to the respiratory tract. However, in some cases Strep can spread to other organs, where it can cause a disease known as necrotizing fasciitis.
How and why it suddenly causes this disease is not known, although there is some evidence that it follows from a bruise or contusion. Current hypotheses state that somehow the damage enables strep to colonise.
However, in order for it to colonise these damaged sites, it has to be able to go systemic first without alerting the immune system.
To do this, bacteria like strep secrete proteins and other compounds which attack immune cells, and the communication systems immune cells use in order to co-ordinate their response against the bacteria.
I am going to talk about one specific protein secreted by strep called "Streptococcus pyogenes Cell Envelope Protease". For short, we'll call it SpyCEP. And I'll show how this one virulence factor can have an extraordinary effect on the immune system.
As near exclusive surface dwellers, we only see the sun-kissed top layers of the vast oceans of our planet. As we descend into the depths, the light from the sun dies away. And as we reach the bottom, we should be plunged into absolute blackness.
But we aren't. There are lights at the bottom of the ocean, and they don't come from nuclear reactions in stars far in the sky.
This illumination comes from living creatures. The great deeps of our planet are populated with creatures who have only ever known light coming from other living things. Species as diverse as Sharks, Squids, Shrimp can exhibit this trait known as Bioluminescence. This is what happens when organisms really shine.
This is the first of a number of posts I will produce on bioluminescence.
In this first post I will explore the many ways organisms use bioluminescence to survive.