Team:Newcastle/22 July 2010

Aim of this experiment

The aim of this experiment is to determine whether B. subtilis 168 is able to take up external arginine.

Materials Required

• Plate consisting of Bacillus subtilis 168 colonies.
• Flame (streaking) Loop
• LB media consisting arginine and ampicillin
• Auto pipette
• Bursen Burner
• Universal Tube

Procedure

• Perform the experiment using aseptic technique.
• Transfer B. subtilis 168 colonies into universal tubes containing 5 ml of LB media and allowed to grow overnight at 37° C.
• Transfer 1 ml of the overnight culture to another universal tube containing 4 ml of the following media:

1. Control (1) - LB media
2. Control (2) - LB media with 10 mM of arginine
3. Control (3) - LB media plus B. subtilis 168
4. Test (1) - LB media with 10 mM of arginine plus B. subtilis 168
5. Test (2) - LB media with 10 mM of arginine plus B. subtilis 168

• Incubate the culture at 37° C with shaking.
• Record the pH at every 30 min interval.Use 20 ul of the culture and measure the pH using the pH measuring stick.

Expected results

Arginine is an amino acid that is acidic. Therefore if B. subtilis 168 is able to take up arginine, it will cause a pH change in the media. This would result in an increase in pH.

1. Control (1) - No change in pH
2. Control (2) - No change in pH
3. Control (3) - Increase in pH, however will be lower than test 1 and test 2.
4. Test (1) - Increase in pH
5. Test (2) - Increase in pH

For actual results, please see 23.07.10 lab results.

Conclusion

For experimental conclusion, please see 23.07.10 lab results.