Measuring Spore Concentration with Hemacytometer
1.
Mix spore solution well.
2.
Add 10 µl of spore solution to each side of the hemacytometer.
3.
Count number of spores in zones A, B, C, D and E on both sides of the hemacytometer, record them, and calculate the average of the two sides. a.
If a spore falls on the left or bottom line DO NOT count it. b.
If a spore falls on the right or top line DO count it
A
E
B
C D
4.
To determine the number of spores per mL a.
(A + B + C + D + E) x 2000
5.
Dilute the spore solution to desired concentration (spores/mL) a.
Use C
1
V
1
= C
2
V
2 formula i.
Ex. If spore solution is found to be 67,000 spores/mL and you want 40mL of 50,000 spores/mL ii.
67,000 x = 40 * 50,000 a.
x = 2,000,000 = 29.85 ~=30mL b.
67,000 iii.
So, you will add 30mL spore solution to 10mL sterile dH20 (40-30=10) to give a final concentration of
50,000 spores/mL in 40mL
6.
You can use the Excel worksheet:
C:\Scab data\Protocols\Current\Hemacytometer Worksheet.xls to print out a data entry form or to calculate spore concentrations.
Nicki Mundell Page 1
D:\726927978.doc
4/14/2020