What is predataxis and how does Myxococcus xanthus use methy

What is predataxis, and how does Myxococcus xanthus use methyl-accepting chemotaxis proteins to sense prey?

Solution

Answer: In bacteria multicellularity emerges as a response to the environmental changes rather than as a function of programmed growth. A chemotaxis-like mechanism used by bacterium Myxococcus xanthus to navigate through the prey colonies of Escherechia coli causes the formation of transient multicellular structures durin predation. This behaviour is known as Predataxis.

In E.coli, chemical stimulus induced chemotaxis has been reported to be spearheaded through the reversible methylation of the methyl-accepting proteins (MCPs) and the methylation is catalysed by methyltransferase (CheR) and methylesterase (CheB).

In M. xanthus there is a homolog of these MCPs i.e the FrzCD protein, where FrzF and FrzG respectively modify the FrzCD receptor.

in the condition od prey density more than 1 million, the FrzCD protein is mainly detected in methylated state and hence the rippling behaviour ensues where cells change the leading pole during surface gliding similar to the flagellar rotation of E.coli. Whereas, as soon as the concentration of prey falls below 1 million cells the FrzCD becomes demethylated and hence rippling behaiour or predataxis stops.