Monday, May 20, 2013
Protective Phages
May 20, 2013
http://www.the-scientist.com/?articles.view/articleNo/35635/title/Protective-Phages/
Summary
Researchers have discovered bacteriophages, or bacterium-attacking viruses, in the protective mucous layer present in many animals, including humans. Since mucus provides a warm, wet environment that is optimal for bacterial growth, scientists infer that the bacteriophages present in the mucus help to control the growth of bacteria in those areas. The researchers pinpointed the Ig receptor in about 25% of the bacteriophages: further research suggests that the Ig receptor causes the viruses to become "stuck" in the mucous layer, whereas without the receptor they would be able to travel due to their small size. Testing phage-treated mucus-producing cells versus cells not treated with phages, scientists monitored growth of an E. coli strain they added to both samples. Results concluded that the phage-treated cells were protected from the bacteria and untreated cells were not.
Connection
This article connects to our current unit on the immune system. The mucus lining the respiratory and digestive tracts helps to defend against infection by providing a physical barrier against bacteria. The article suggests a more specific role for the mucus layers: the destruction of harmful bacteria using symbiotic phages. Whether the phages are specific defense against pathogens, or are an extension of the nonspecific immune system is unclear, but the bacteriophages play a definite role in bacterial defense.
Subscribe to:
Post Comments (Atom)
What are other functions of the mucus layer--other than destroying bacteria?
ReplyDeleteThe main function of mucus in the respiratory tract is to trap particles such as pollen and dust before they reach the lungs. This keeps the lungs clear of any foreign particles. The mucus also plays a role in moisturizing air before it enters the lungs, keeping the tissue from drying out.
DeleteIn the digestive system (especially the small intestine), mucus creates a barrier to isolate the environment inside the intestine from the tissue outside.
DeleteAre there instances where the symbiotic phages can be found absent from the protective mucous layer in humans?
ReplyDeleteBacteriophages are very abundant, in fact some scientists estimate them to be more abundant than bacteria themselves. Therefore, a case in which bacteriophages were not present in the mucous layer would be very unlikely.
Delete