If you are requested to prepare a spread plate with a diluti

If you are requested to prepare a spread plate with a dilution on the plate of 1:1000 and you are provided with a concentrated culture, a test tube with 5ml of sterile water and several sterile empty tubes, describe how you would prepare this spread plate. assume that .1 ml of the dilution is spread onto the plate.

Solution

To make 1/1000 of concentrated culture with sterile water the easist way is to make a 1/10 dilution of the 1/100 dilution (which is prepared by 1/10 diluted culture in a empty tube and bring 10 parts water) with 10 parts of the total volume.
   1/100 X 1/10 = 1/1000

it can be explained/ prepared in simpler manner as:

0.1ml of stock culture/ 1ml of water X 1/1 X 1/1 X 1/1 = 1/1000 dilution

this means taking only 0.1 ml of original stock and diluting it 1/1 for four times this will produce a 1/1000 dilution of stock in sterile water.