If you placed a urinesoaked agar cube in the vicinity of agg

If you placed a urine-soaked agar cube in the vicinity of aggregating amoebae, what results would you expect and why? (Note: urine is a complex substance that contains relatively high levels of cyclic AMP.)

Solution

Ans. Human urine has [cAMP] around 0.53- 0.75 µg/ mL. An amoeba cell can sense as small as 0.1 µg/ mL [cAMP] in the surrounding.

in the environment deprived of energy sources.

in the environment deprived of energy sources.

The scarcity of energy sources in the surrounding triggers the production of cAMP in amoeba cells. The resultant intracellular cAMP triggers the aggregation of individual amoeboid cells towards a central cell that has relatively higher [cAMP] acting the point of aggregation (to which all other cells come).

In presence of higher extracellular cAMP (in form of urine soaked agar cube), the individual cells exhibit chemotaxis towards the source of higher [cAMP] embedded in agar cube, but NOT towards the central cell. As a result, the process of aggregation is disrupted.