Question

Gingivitis is a Periodontal pathogen that causes dental plaques. There are more than 500 species in the oral cavity. A study states that at least 3 genera of bacterial isolates were able to stimulate light production and about 170 were able to respond to the autoinducer AI-2. The signal for AI-2 induces the growth of the bacteria which eventually increases the severity of the infection.

a) Since 170 bacterial isolates respond to AI-2 quorum sensing alone, how many bacterial isolates use:

agr quorum sensing

hsl quorum sensing

AI-2/agr quorum sensing

AI-2/hsl quorum sensing?

b) If AI-2 induces growth and increases the severity of infection, do bacteria that use agr quorum sensing do the same thing or do they differ? What about bacteria that use hsl quorum sensing?

Answer 1

Gingivitis : It is the inflammation of gum tissues that surrounds the teeth.most cases swelling occurs and this is due to the accumulation of build up of plague. If left untreated this condition would progress to Periodontitis. Plague is the bofilm produced by the bacteria around the teeth

.Quorum sensing is the method in which bacteria l respond to cell density increase.

Al-2 or Autoinducer-2 is a signal molecule that is produced by LuXs,which is an enzyme found in many bacterial species.

The bacterial species like Staphylococcus aureus causes variety of infection,the extent of virulence factor is controlled by agr quorum sensing system.it comprises of response regultors,AgrA, AgrC etc. Many Gram positive and Gram negative bcterias show different type of quorum sensing.

Peridontal pathogenic bacteria posses Al-2 quorum sensing system.they uses it for the regulation of biofilm production.aL-2 induce the bacterial growth and as a result infection progresses.

In bacteria using hsl (homosereine lactone)quorum sensing: used by large number of gram negative bacteria. As these mechanism also provides a platform for monitoring the cell population by the bacteria ,which is similar to other quorum sensing system.