Molecular Genetics Practical Write Up Lab Report

Molecular Genetics Practical Write Up - Lab Report Example typhimurium, and TA 1535, TA 1537, TA 1538 mutants. 2mL of molten overlay agar (kept in a 45 °C water-bath) was added in to a sterile tube. After waiting for the agar to cool slightly (roughly 37 °C), 0.1mL of the bacterial culture was added using a Gilson pipette fitted with a sterile tip. Immediately the molten agar was poured along with the bacterial strain onto a E-medium plate ensuring even distribution of the overlay agar on the plate surface. The plate was then allowed to cool before incubating at 37 °C overnight. 2mL of molten overlay agar was added in to a sterile tube and after slightly cooling, 0.2mL 0.5mM histidine + 0.5mM biotin solution was added. 0.1 mL of the bacterial culture was added using a Gilson pipette fitted with a sterile tip and immediately the molten agar was poured along with the bacterial strain onto a E-medium plate ensuring even distribution of the overlay agar on the plate surface. The plate was then left to cool and later incubated at 37 °C overnight. 2mL of molten overlay agar was added into a sterile tube. After the agar had slightly cooled, 0.2mL 0.5mM histidine + 0.5mM biotin solution and 0.1mL of the 0.1M histidine solution was added. Immediately pour the molten agar was poured onto a E-medium plate ensuring even distribution of the overlay agar on the plate surface and the plate allowed to cool. Six serial dilutions of the bacterial culture in  ¼ strength Ringer’s solution ( 10-1, 10-2, 10-3, 10-4, 10-5 and 10-6) were prepared by adding, for instance for the 10-1, 100ÃŽ ¼l of the bacterial culture in a sterile eppendorf tube and adding 900ÃŽ ¼l of  ¼ strength Ringer’s solution. This diluted culture was used to carry out the next dilution and repeat this was repeated six times in total in order to get the 10-6 dilution. The plate was divided into two halves using a marker pen and marking the bottom of the plate one side was marked 10-5 and the other side 10-6. 10ÃŽ ¼l of the 10-5 dilution was dropped using a Gilson