Bio-Rad Quantum Prep Plasmid Kits - Manual (Page 4)

plasmids, as that will not usually result in higher yields using
this protocol. For low-copy number plasmids (e.g. pBR322),
up to 60 ml of culture can be used with the volumes in this
protocol. Larger volumes may not result in higher yields
due to the increase of other cellular contaminants.
It is highly recommended that the plasmid DNA be
isolated from a host strain that contains a mutation in the
endonuclease I gene (endA) of E. coli. Isolation of DNA
from strains containing active endonuclease I gene product
(such as HB101 and MC1061) may result in samples which
contain trace amounts of nuclease. Additional precautions
and wash steps are required with these strains (see Section
2.1 and 2.2). For the highest quality DNA, these host strains
should be avoided.
2.1 Recommendations for Best Results
A precipitate may form in the lysis and neutralization
solutions due to cold temperatures from ambient winter
shipping conditions, cool laboratory temperatures, or factory
storage conditions. This will not affect the performance
of the product. If a precipitate is observed, warm the bottles
to 37 °C until it is redissolved. Use and store at room tem-
perature.
• Add 125 ml of 95% ethanol to the Midiprep Wash
Buffer before first use.
• For increased plasmid yield a second elution may
be performed. Eluting with water or TE heated to
70 °C may also result in an improved yield.
1.2 Contents
The Quantum Prep plasmid midiprep kit contains suf-
ficient reagents for 20 plasmid midipreps. Additional
Midiprep Wash Buffer will be required if following rec-
ommendations for EndA+ strains such as HB101 and
MC1061.
Cell Resuspension Solution 110 ml
Cell Lysis Solution 110 ml
Neutralization Solution 110 ml
Quantum Prep matrix 20 ml
Midiprep Wash Buffer 125 ml
Spin columns and caps 20
2 ml microcentrifuge tubes 40
1.3 Storage and Stability
All components are guaranteed for 12 months from the
date of purchase, when stored at room temperature and
used as described in this manual.
Section 2
Protocol
Yields of plasmid DNA depend on factors such as
vector copy number, insert DNA, growth conditions, and
media. This midiprep protocol has been optimized for 40 ml
of culture of high-copy number plasmids grown in Luria
Broth or Terrific Broth. It is not recommended that larger
volumes of culture be used for medium to high-copy
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