Intro to Bacteriophages

So, Tim studies bacteriophages...well, what the heck are they anyway. Here's a very brief introduction as to what they are and do. There may be some links around the site that will tell you more.

A bacteriophage (from 'bacteria' and the Greek "phagein", meaning 'to eat') is any one of a number of virus-like agents that infect only bacteria. The term is commonly used in its shortened form, phage.

Typically, bacteriophages consist of an outer protein hull enclosing genetic material. The genetic material can be dsRNA, ssDNA, or dsDNA between 5 and 500 kilo base pairs long with either circular or linear arrangement. Bacteriophages are much smaller than the bacteria they destroy - usually between 20 and 200 nm in size.

Phages are estimated to be the most widely distributed and diverse entities in the biosphere, numbering 10^31 virions. Phages are ubiquitous and can be found in all reservoirs populated by bacterial hosts, such as soil or the intestine of animals. One of the densest natural sources for phages and other viruses is sea water, where up to 10^9 virions per milliliter have been found at the surface, and up to 70% of marine bacteria may be infected by phages. They are also found in drinking water and in some foods, including fermented vegetables and meats e.g. pickles, salami, where they serve the function of controlling any growth of bacteria.

Phages are very specific to bacteria, and thus are more accurate and potent than antibiotics. They have been used for over 60 years as an alternative to antibiotics in the former Soviet Union and Eastern Europe. They also have no known side effects, as opposed to drug therapy. They are now seen as a hope against multi drug resistant strains of many bacteria.