Describe briefly how you would detect the presence of a non-culturable prokaryote in an environmental sample.

Using microscopy methods such as fluorescence microscopy and polymerase chain reaction (PCR).

Explanation:

A bacterium that is viable but non-culturable refers to those bacteria that are in a very low metabolic state (dormant state) that don't grow but is alive. Methods based on culture will not be able to detect a viable but non-culturable bacteria, because these bacteria will not grow and in few cases if the bacterium could be cultured, it only grows in very specific conditions. The most common methods used to check for the presence of bacteria that are viable but non-culturable is the fluorescence microscopy. The disadvantage of this technology is that don't discriminate between live and dead cells, it only detects its presence. Another common technology is a polymerase chain reaction (PCR), that detects DNA, but this technique also doesn't discriminate between living or dead cells. But usually is combined with stains to detect a damaged of the membrane, this damage refers to nonviable bacteria.