Identification of Auxotrophic prerequisites in Bacterial

Materials such as Bunsen burner, minimal media plates, 70% ethanol, auxotrophic E.coli strain, dips, impregnated filter paper discs and pipette use used in the experiment to identify auxotrophic requirements in bacteria. First, the cultured plates were labeled accordingly at the base. With the help of a pipette, a measure of 100µL of E.coli culture was spread at the surface of plates of minimal medium agar. A special technique known as the sterile technique was employed to place all the eight nutrient impregnated discs in agar in an orderly manner as was labeled. The two plates were then inverted and incubated for a period of 24 hours at a temperature of 37ºC. After twenty-four hours, the plated were observed and examined thoroughly and data entered in the table.

In the identification experiment of antibiotic resistance in bacteria, forceps, spreader, Bunsen burner, 70% ethanol, tips, antibiotic discs, pipette, strain of antibiotic resistant E.coli and a plate of nutrient agar materials were used. First, the nutrient agar plate was labeled at the base. A measure of 100µL of E.coli culture was spread at the surface of NA (nutrient agar) plate. The bacteria was then spread using the sterile techniques. The antibiotic-impregnated filter paper discs were placed on the NA plate using the forceps. Antibiotics were placed at suitable distance from one other.. The plate was then inverted and incubated for a period of 24 hours at a temperature of 37ºC. A table was then filled after the duration of the experiment and after examining the plates properly.

In the testing of mutagens experiment, minimal culture plates were labeled accordingly with a permanent marker. TA100 culture of 100µL was applied on the plates’ surface. The bacteria was immediately spread using sterile technique. In the center of one of the plates was placed a filter paper discs before adding 10µL of test solution to the disc. The same procedure was repeated for all the remaining solutions. The plates were inverted and then incubated for a period of 24 hour at a temperature of 37ºC. The observations were then recorded in a table after examining the plates.

In the experiment on the effect of Ultraviolet light on mutagens, the material used include aluminum foil, 70% ethanol, Bunsen burner, UV lamp, five nutrient agar plates, bacteria spreader, four 6cm by 10cm cards and culture of E.coli. First, nutrient agar plates were labeled accordingly followed by spreading of E.coli culture in the plates using sterile technique. A line was drawn on the plate dividing it into two sections; one was to be exposed to ultraviolet light while the other was not to be exposed to UV light. Plates cover was then removed and the 6cm by 10cm card was placed over one of the sections and secured by a tape. It was then exposed to UV light before the plate covers were replaced. The plates were inverted and wrapped with aluminum foil. This was followed by inversion of the plates, which were then incubated for 24 hours at a temperature of 37ºC. The plates were examined after 24 hours and colonies counted and recorded in a table.