Quorum sensing controls the expression of virulencein many pathogenic bacteria. Usually, pathogens express toxins in response to receptor activation by ligand binding at high cell density. V. cholerae (thecausative agent of cholera) does the opposite; its virulence genes are expressed only at low cell densitybecause its quorum-sensing receptor is repressed byligand binding. The unusual “reversed” mechanismfor activating virulence genes in V. cholerae has suggested to scientists a simple idea for generating a newkind of antibiotic for the treatment of cholera.Explain
Quorum sensing controls the expression of virulence
in many pathogenic bacteria. Usually, pathogens express toxins in response to receptor activation by ligand binding at high cell density. V. cholerae (the
causative agent of cholera) does the opposite; its virulence genes are expressed only at low cell density
because its quorum-sensing receptor is repressed by
ligand binding. The unusual “reversed” mechanism
for activating virulence genes in V. cholerae has suggested to scientists a simple idea for generating a new
kind of antibiotic for the treatment of cholera.
Explain
Quorum sensing is a type of signaling that works between bacteria present in a region. Bacteria release certain chemical molecules that act as a signal for other bacteria present in the vicinity. The bacteria alter their gene expression with respect to the signal received. The response to the cell density in bacteria is one such example of quorum sensing.
The virulence is defined as the ability of a microbe to infect a host or cause damage to it. Bacteria release some kind of autoinducers that when reaches a threshold (quantitatively) activate the virulence genes in them. The production of autoinducers depends on the density of cells. This property helps scientists develop therapeutic drugs that can combat bacterial virulence.
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