Question

Membrane Filtration

1.What is a microbe grew on the TSA median and not on the EMB media? If this was not the results of experimental error then what would that mean?

2. Explain how you created glowing E.coli that grew on a plate treated with ampicillin (not the protocol) use scientific terminology. Provide 2 examples of eukaryotic organisms that have been engineered to glow by similar means

Answer 1

1). Tryptic soy agar medium is a universal growth media, which allows the growth of most of the bacterial species in general.

Eosin methylene blue (EMB) agar is selective and differential growth media for gram-negative coliforms. It contains two dyes namely eosin and methylene blue in the 6:1 ratio.

This media contains the bile salt that is toxic for gram-negative bacteria that are other than coliforms. The dyes inhibit the growth of gram-positive bacteria and distinguish the lactose fermenting (E.coli) and non-lactose fermenting (Eg: salmonella species) by means of colour indication. The lactose fermenting bacteria appear as cells with dark centers.

If the microbe grows on TSA but not on EMB means, it is not a gram-negative coli bacteria.