Question

Question 1

How could you identify bacteria in a biofilm if it could not be cultured?

Question 2

How can bacteria produce or modify enzymes to control how much metabolic product is made?

Answer 1

1) The identification of such unculturable bacteria in biofilm can be done through various techniques like :

a- Direct Counting methods:  Nalidixic acid + Yeast extract is added to population. Nalidixic acid stops DNA replication and the yeast extract promotes protein synthesis. So the bacteria will get elongated and can be identified with visual inspection through a microscope.

b- Dye Reduction Test: Reduction of colourless CTC by electron transport activity of bacteria will produce CTC formazan, which is a red fluorescent dye and gets accumulated inside the cell.

c- Genetic based method: Polymerase Chain Reaction (PCR) can be used to detect such bacteria by amplifying small amounts of DNA from a target bacterium to detectable levels without requiring cell replication.

2) It can be done by production of allosteric proteins. They modulate the metabolism by concentration of small molecules that are able to bind to the effector sites of the enzyme. If the allosteric site gets occupied, then the enzyme gets inactivated, hence reducing the metabolism.,