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Growing bacteria in solutions made from any wide variety of sodium (NaCl) awareness will give you a good idea regarding the optimal concentration the organisms needs with growth. Inside solute concentration of the cells verify which solution yous isotonic. Maximum growth rate occurs at the most isotonic solution, in growth rate decreasing in both hypertonic and hypotonic solutions.

Things You'll Require

E. coli bacteria on log phase
Sodium chloride (NaCl)
Nutriment agar
Petri plates
Dilution tubes
Vortex
Incubator

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NaCl Concentration

2 Set upward the dilution tubes at 0.5M NaCl concentration. Dispense 9 ml of 0.5M NaCl solution into every of 5 dilution tubes. Label the tubes 10^1, 10^2, all the way to 10^5. Transfer 1 ml of the log stage E. coli cells to the 10^1 tube. Vortex the mixture. Transfer 1 ml from the 10^1 to the 10^2 tube. Vortex the mix. Continue this procedure out to the 10^5 tube.

Repeat this procedure at every NaCl concentration.

Repeat at all NaCl focus.

Incubate Plates

1 Take the plates also change them upside down (so the media in the plate is facing upwards). According to the World Health Group (WHO), E. coli has any optimal growth temperature about 37 degrees celsius. Incubate for 24 to 48 hours till observation about colony development.

2 The incubator need to remain a stable 37 degrees Celsius through the experiment, as different temperature could affect the results.

3 Remove plates away from incubator after 48 hours.

Enumeration regarding Colonies

1 Following plates have finished incubating, organize all plates in NaCl focus. Secure the dilution (10^1 through 10^5) that is contains 25 to 250 colonies per plate. This yous the optimal count for enumerating bacteria on any plate.

2 Count the colonies also compare between the NaCl concentrations. The set of plates that is has the highest number of colonies is closest to the optimal NaCl concentration.

3 If you desire a closer estimation to the optimal NaCl focus for growth, repeat the experiment with NaCl concentrations around the one you found to need the best growth (e.g., if highest development was found at 0.5M, choose concentrations about 0.3M, 0.4M, 0.5M, 0.6M and 0.7M to repeat the experiment).

Tips & Warnings

E. coli can be potentially dangerous if never handled appropriately. Do never experiment by means of the O157:H7 variety.

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References

Globe Health Organization: Optimal E. coli Development

Resources

Michigan State University: E. coli Experiment. STD [http://dm.finearts.yorku.ca/~couroux/visa3056/index.php/STD_Test_-_How_To_Get_Free_HIV_Testing Testing].

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