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1. We perform customized sample preparation
using our proprietary protocols that best fit your specific
sample type.
2. Samples containing biohazard materials: We do NOT accept
samples containing any biohazard material. If your samples
contain any biohazard materials, please make sure to deactivate
them completely using the appropriate procedure and please
declare them in the order form. In addition, we do NOT accept
any samples containing Level 4 biohazard material even if
deactivated. Please refer to the following link for the
rank of biohazard material:
http://en.wikipedia.org/wiki/Biological_hazard.
3. Please follow the general
principles in getting your samples ready for 2D DIGE
experiment.
4. Please click on your sample type for additional tips:
General
principles:
Proteins in the samples must be fully denatured, reduced,
and solubilized for effective IEF separation. Samples are
rapidly lysed in a strongly denaturing solution with brief
sonication in the ice container. Protease inhibitors can
be added in the lysis solution to prevent protein degradation.
Proper conditions for lysis vary greatly depending on the
source of the samples, and should be determined empirically.
A minimum of 25 ug total protein, regardless of the source
of samples, is required for analytical 2D DIGE. Depending
on the abundance of the target protein, at least 200 ug
total protein may be needed for prep-DIGE gel, spot picking
and mass spectrometric analysis. Please submit enough sample
protein so that we can complete your project successfully.
We can perform the standard sample prep steps for the customers.
For the plasma and serum sample immuno-depletion, additional
charge will apply. Please provide us with specific instructions
if special handling is required. If you wish to lyse the
samples yourself, please adjust the final concentration
of total protein to 3-20 mg/ml. Please contact us for the
appropriate lysis buffer to use for your samples.
The following are the basic guidelines for protein lysate
preparation:
- It is essential that lysis buffer is free of both primary
amines and sulfhydryl groups.
- Follow the sample preparation protocol described in
GE Healthcare's DIGE section.
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Not
Acceptable
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Acceptable
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Reducing agents (e.g., DTT, TBP)
Buffers other than Tris
Salt (e.g., NaCl)
Ionic detergents (e.g,. SDS)
Nucleic acids
Polysaccharides
Lipids
Phenolic compounds
Insoluble material
Other small ionic molecules
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Tris base (< 30 mM)
Urea
Water
Non-ionic or zwitterionic detergents (e.g. CHAPS)
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Customers may consider the following sample preparation modifications
to achieve optimal results.
Laser Capture Micro-dissection (LCM) capture to separate
tumor cells from normal cells in the same tissue sample
FACS or Cell sorting to separate different cells (cell
cycle stage or cell types)
Protein Complex isolation and sample fractionation
Cell surface membrane protein isolation
Mitochondria isolation, ER, nucleus, plasma, protein fractionation
Pre-isolating the specific cells of interest
- Bacteria.
Bacterial cells are pelleted by centrifugation. Pellets
are washed twice with cell washing buffer (10 mM Tris
HCl, 5 mM magnesium acetate, pH 8.0). After the final
spin, the supernatant must be removed as completely as
possible. Cell pellets are quickly frozen in liquid nitrogen
or dry ice/ethanol bath. Frozen cell pellets can be shipped
to us on dry ice.
- Yeast.
Yeast cells are pelleted by centrifugation. Pellets are
washed twice with cell washing buffer (10 mM Tris-HCl,
5 mM magnesium acetate, pH 8.0). After the final spin,
the supernatant must be removed as completely as possible.
Cell pellets are quickly frozen in liquid nitrogen or
dry ice/ethanol bath. Frozen cell pellets can be shipped
to us on dry ice.
- Mammalian
cell lines. For suspension cultures, cells
are pelleted by centrifugation. Pellets are washed twice
with PBS or cell washing buffer (10 mM Tris-HCl, 5 mM
magnesium acetate, pH 8.0). After the final spin, the
supernatant must be removed as completely as possible.
Cell pellets are quickly frozen in liquid nitrogen or
dry ice/ethanol bath. Frozen cell pellets can be shipped
to us on dry ice.
For adherent cultures, the cell monolayer can be washed
twice with PBS or cell washing buffer (10 mM Tris-HCl,
5 mM magnesium acetate, pH 8.0). After the second wash,
a small volume of cell washing buffer is added to the
plates (1 ml for each 100-mm plate), and cells are scraped
from the plates. The scraped cells are transferred to
eppendorf tubes, and cells are pelleted by a 1-minute
spin at low speed. Remove the supernatant as completely
as possible. Cell pellets are quickly frozen in liquid
nitrogen or dry ice/ethanol bath. Frozen cell pellets
can be shipped to us on dry ice.
- Enriched
cell organelles (nuclei, mitochondria, membrane fraction,
etc.). Following the purification steps, wash
the enriched cell organelles twice with cell washing buffer
(10 mM Tris-HCl, 5 mM magnesium acetate, pH 8.0). If necessary,
neutral substances (such as sucrose) may be included in
the washing buffer. After the final wash, the supernatant
must be removed as completely as possible. Pellets are
quickly frozen in liquid nitrogen or dry ice/ethanol bath.
Frozen pellets can be shipped to us on dry ice.
- Purified
protein complex. If you use IP in getting protein
complex, please do the IP and the washing the same way
you did before. At the end, please transfer the beads
to a 1.5 ml plastic tube, and wash the beads once with
0.5 ml of water (this should get rid of the salt which
may interfere with IEF). Please remove water as completely
as possible after the final wash. The bead pellets can
be kept at -20C and sent to us on dry ice. We will elute
protein complex from the beads using a buffer that contains
2 M thiourea, 7 M urea, 4% CHAPS and 30 mM This-HCl pH
8.8.
- Animal
tissue. About 5-10 mg of animal tissue (approximately
2 mm x 2 mm x 2 mm in size) is needed for 2D DIGE analysis
and the mass spectrometric protein analysis. We suggest
that the contaminating blood be removed using PBS. Tissues
can be flash frozen in liquid nitrogen after harvest.
The tissue is then ground to a frozen powder in a mortar
and pestle. Frozen tissue powder can be shipped to us
on dry ice.
Tissues that are embedded in OCT blocks are fully compatible
with 2D DIGE analysis. Embedded tissues can be shipped
to us on dry ice.
- Human
tissue. . About 5-10 milligrams of human tissue
(approximately 2 mm x 2 mm x 2 mm in size) is needed for
2D DIGE analysis. Removing the contaminating blood by
washing with PBS is recommended. Tissues can be flash
frozen in liquid nitrogen after harvest. The tissue is
then ground to a frozen powder in a mortar and pestle.
Frozen tissue powder can be shipped to us on dry ice.
Tissues that are embedded in OCT blocks are fully compatible
with 2D DIGE analysis. Embedded tissues can be shipped
to us on dry ice.
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Laser
captured micro-dissected (LCM) cell population.
A minimum of 20,000 laser captured micro-dissected cells
is required for 2D DIGE analysis. After LCM, adherent
cells are eluted from the caps with small amount (10-15
l per cap) of lysis buffer. Lysates are collected (and
pooled if more than one cap) in microcentrifuge tubes,
frozen in liquid nitrogen or dry ice/ethanol bath. Frozen
lysates can be shipped to us on dry ice and we will
complete the lysis step.
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