Bio-Rad Aurum™ Total RNA Mini Kit - Manual (Page 7)

Section 5
Before Using the
Aurum Total RNA Mini Kit
Please read the following guidelines before proceeding with the total RNA
purification.
Starting Material Amounts
The Aurum total RNA mini kit is designed to process up to the amounts
indicated below (per column):
• 2 x 10 6 mammalian cultured cells
• 3 OD • ml* of gram-positive or gram-negative bacteria
3 OD • ml of bacteria roughly corresponds to a culture volume of 500–750 µl
• 3 OD • ml of yeast (S. cerevisiae)
3 OD • ml of yeast roughly corresponds to a culture volume of 600–1,000 µl
• 40 mg animal tissue
• 60 mg plant tissue
Processing larger amounts of starting material may lead to column clogging
and reduced RNA purity.
*Spectrophotometric determination of bacterial or yeast culture density is a
REQUIREMENT for optimal total RNA isolation from these starting materials.
To determine the density of a bacterial or yeast culture (OD
600
), combine 50 µl
of culture with 950 µl growth medium (20-fold dilution). Use the growth
medium as a blank and take the spectrophotometric reading at
l = 600 nm.
Multiply this figure by 20 to calculate the OD
600
value of the undiluted bacterial
or yeast culture. Depending upon the OD
600
value, a specific volume of the
culture will be selected to provide an optimum amount of bacteria or yeast for
processing. To calculate the volume of culture required, use the following
equation:
(OD
600
of undiluted culture)** x (culture volume in ml) = # OD • ml
For example, 3 OD • ml of yeast would require 500 µl of an undiluted culture
with an OD
600
= 6.
** 1 OD
600
is equivalent to approximately 8 x 10 8 bacterial cells/ml, or 1 x 10 7
yeast cells/ml.
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