Lesson 3 - Nucleic Acid Isolation Flashcards
application of nucleic acid extraction
- DNA profiling
- molecular biotechnology
- phylogenetic studies
where is high quality used for
- restriction digestion
- gene cloning
- amplification
- DNA sequencing
Common sources of DNA
- whole blood
- hair
- sperm
- bones
- nails
- tissues
- saliva
What are the five general steps in nucleic acid isolation
- tissue homogenization and cell lysis
- denaturation and separation of other biomolecules from nucleic acid
- precipitation of nucleic acid from aqueous phase
- washing of precipitated nucleic acid
- drying of pellet and dissolution of dried pellet
mechanical method for tissue homogenization
- sonication
- grinding
refers to the process of applying sound energy to agitate particles or discontinuous fibers in a liquid
Sonication
reduce the size of materials to give a usable form or to separate their components
grinding
chemical used for cell lysis
- buffer
- salt
- detergent/surfactant
- denaturants
buffer
Tris-HCl
salt
NaCl
detergent/surfactant
SDS (sodium dodecyl sulfate)
purpose of detergent
emulsify phospholipids
denaturants
guanidinium
what does guanidinium do
inactivates RNases / DNases
used to treat other cellular components
enzymatic treatment
enzymatic treatment examples
- lysozyme
- cellulase
- pectinase
chemical treatment for denaturation and separation of other biomolecules from the nucleic acid
- phenol
- choloroform
- isoamyl alcohol
- CTAB
- PVP
denature proteins
phenol
what does phenol denature
proteins
removes proteins and lipids
chloroform
what does chloroform remove
proteins and lipids
removes phenol and chloroform
isoamyl alcohol
what does isoamyl alcohol remove
phenol and chloroform
removes polysaccharides
CTAB (cetyltrimethylammonium bromide)
what does CTAB (cetyltrimethylammonium bromide) remove
polysaccharides
removes polyphenols (alkaloids)
PVP (polyvinylpyrrolidone)
what does PVP (polyvinylpyrrolidone) remove
polyphenols (alkaloids)
used in enzymatic treatment during the denaturation and separation of other biomolecules from the nucleic acid
- protease
- proteinase
sample will be separated by density with heavier stuff at the bottom of the tube and lighter stuff on top
centrifugation
formed during centrifugation
- supernatant
- precipitate
clear liquid free of precipitate located above the solid part
supernatant
solid that forms at the bottom after centrifugation
precipitate
monovalent cations
- sodium
- potassium
alcohol used in the precipitation of nucleic acid from aqueous phase
- ethanol (95%)
- isopropanol (95%)
used to wash precipitated nucleic acids
70% ethanol / isopropanol
two types of dyring of pellet
- air drying
- vacuum drying
where is dissolution of dried pellet done
- sterilized molecular grade water or
- TE (Tris-EDTA)
EDTA
Ethylenediaminetetraacetic acid
inactivates DNases
EDTA
what does EDTA inactivate
DNases
after isolation,
__ treatment if DNA is isolated
RNA
after isolation,
__ treatment if RNA is isolated
DNA
storage of isolated DNA
- stock solution
- working solution
stock solution temp.
-20°C to -80°C
working solution temp.
4°C
stock solution
pellet + Tris-EDTA
how to determine purity and concentration of DNA isolation
- using DNA standard (different concentrations)
- UV spectrophotometer (purity)
laboratory method used to separate mixtures of DNA, RNA, or proteins according to molecular size.
Gel electrophoresis
To assess purity using the UV spectrophotometer, what is done?
- take readings at 260 nm - 280nm
- get ratio of A260/A280
- get ratio of A260/A230
high purity for NA sample
A260/A280 = 1.8 to 2.0
A260/A280 < 1.8 (or <1.6)
protein contamination
protein contamination
A260/A280 < 1.8 (or <1.6)
A260/A280 > 2.0
chloroform/phenol contamination
chloroform/phenol contamination
A260/A280 > 2.0
if A260/A230 < 2.0, it is contaminated with:
- carbohydrate carryover
- residual phenol/guanidinium
- other organic compounds
- salts