How do beneficial bacteria protect us?

Linda Geddes

The beneficial bacteria in our gut bring many benefits. They both reduce the number of harmful organisms and release molecules that reduce inflammation and prevent colitis.

Bacteroides fragilis is very common in the human gut. They produce a molecule called PSA. Research in mice showed that PSA had an effect on the development of T. immune cells.

In order to understand more thoroughly, Dennis Kasper of Harvard Medical School and his colleagues injected mice with two strains of B. fragalis, one strain could produce PSA in one line. In addition, another popular bacterium, Helicobacter hepaticus, causes colon inflammation in mice.

Kasper said: 'Mice were injected with normal strains of B. fragalis without inflammatory bowel disease'.

Limit inflammation

(Photo: Source Molecular Corporation)

Additional tests showed that PSA prevents the intestinal immune cells from producing chemicals that stimulate inflammation when H. hepaticus enters the intestine.

PSA in the mouth also helps mice not get colon inflammation, which increases the possibility that PSA and some other molecules of beneficial bacteria can actually treat human inflammation.

Kasper said: 'The results show that bacterial molecules can regulate the balance between health and disease'.

He cautioned that PSA is not the only factor in the prevention of inflammatory bowel disease, but B. fragalis is not the only bacterium that produces PSA affecting the development of the immune system. translation in humans.

However, it helped to formulate a new hypothesis called 'hygiene hypothesis' that suggested that limiting children's activities to prevent infection could lead to the formation of an allergy risk and Autoimmune diseases.

"Perhaps diseases such as colon inflammation involve a small number of bacteria such as B. fragalis compared to bacteria like helicobacter," Kasper said .

Interaction is decisive

Kasper argues that the noncoding genome produces factors necessary for the development of a healthy immune system, but our health depends on decisive interaction with the set. The genes of the microbiota in our gut.

He said: 'This means that intestinal bacteria actively connect to the host's immune system, thereby emphasizing the importance of microorganisms to our health.'

'If specific bacterial groups work to enhance the health of the host, then disease can be the result of the absence of these bacteria as well as the beneficial molecules they create'.

The reference article is published in Nature (doi: 10.1038 / nature07008).