What is a #bacteriophage and how many different types of phage exist?
A phage is a virus that infects a bacterium. People often get very confused about what the difference is between a virus and a bacterium. A virus, like a bacterium, is also a microorganism, but unlike bacteria, it needs to have a host to be able to replicate and propagate. All bacteria have these natural viruses, just like we have viruses that make us sick and our children sick.
All bacteria have their own sets of viruses, so they’re very specific. A virus, for example, that infects E. coli bacteria wouldn’t infect a different species of bacteria.
Over 90% of all viruses found that infect bacteria fall into three families or ‘types’ of viruses, but for the thousands of types of bacteria that exist, there are even more sub-types of viruses within these three families.
The three major families of viruses are known as myoviruses, siphoviruses, podoviruses. They’re double-stranded DNA viruses and have different shapes.
“Myo” means muscle and these viruses are have a long, contractile tail. Typically this type of virus is used to illustrate what a phage looks like. If you look up ‘bacteriophage’ on a search engine, you will see lots of images of myoviruses looking a bit like an ant or a lunar lander.
“Sipho” means siphon and siphoviruses have a long, non-contractile tails. Sometimes it’s flexible and sometimes it’s not. It is like a harpoon, in terms of the way it gets through the bacterial ce
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