RNA was extracted from lab-safe E. coli cells used to test the LAMP reaction. Procedure was completed as described in Qiagen RNeasy Mini kit (1).
Materials
Qiagen RNeasy Mini Kit
Target Cells
100% Ethanol
RNAse-Free Water
Centrifuge
Methods
Grow 5 mL of cells. Mix 500 μL of cells with 1,000
μ
L RNA protect mixture in a spin column.
Incubate for 5 min. Centrifuge at 10,000 rpm for 1 min and discard the flow-through.
Add TE and lysozyme at 2 mg/mL of the final solution (20
μ
L of 100 mg/mL lysozyme and 980
μ
L TE). Vortex and incubate at 56°C for 5 mins.
Add 700
μ
L of Buffer RLT with BME (2 mL RLT and 20
μ
L BME) to the column. Centrifuge at 10,000 rpm discard the flow-through.
Add 500
μ
L of 100% EtOH to the column. Centrifuge at 10,000 rpm discard the flow-through.
Continue protocol according to kit Step 7.
Genomic DNA Extraction
Genomic DNA extraction was performed during the preliminary stages of our project in order to test the LAMP protocol. Entire extraction was completed as described in Thermo Fisher GeneJET Genomic DNA Purification Kit (2).
Materials
Thermo Fisher GeneJET Genomic DNA Purification Kit
Bacterial RNA
50% Ethanol
Centrifuge
Methods
Extract genomic DNA according to kit procedure.
PCR DNA Amplification
PCR was carried out as proof-of-concept and to amplify our modified Bst gene fragment. PCR cleanup was completed as described in Thermo Fisher GeneJET PCR Purification kit.
Materials
Stock dNTPs (10 mM)
Template DNA
Forward and Reverse Primers
DNA Polymerase
DNA Polymerase Buffer
Betaine
Thermal Cycler
Thermo Fisher GeneJET PCR Purification Kit
Methods
Add reaction components in the following volumes:
Forward Primer
0.5 μL
Reverse Primer
0.5 μL
DNA polymerase
0.5 μL
DNA polymerase buffer
10 μL
dNTPs
1 μL
Template DNA
1 μL
Betaine
13 μL
Sterile Water
23.5 μL
TOTAL
50 μL
Place reaction tube in thermal cycler for the following cycles:
Cycle Step
Temperature (°C)
Time
Number of Cycles
Initial Denaturation
98
1 min
1
Denaturation
98
10 sec
30
Annealing
primer dependent
30 sec
30
Extension
72
DNA pol dependent
30
Final Extension
72
5 min
1
Termination
4
Indefinite
1
PCR cleanup reaction product according to kit procedure.
DNA Gel Electrophoresis
Materials
Agarose Powder
LB Buffer Solution
Red Safe DNA Stain
10X DNA Loading Dye
10X DNA Ladder
Gel Electrophoresis Chamber and Comb
Microwave
Methods
Add 0.5 g of agarose, 50 mL of LB Buffer Solution, and 2.5
μL of Red Safe stain to an Erlenmeyer flask.
Heat the solution in microwave to 1 min and pour into gel electrophoresis chamber. Add comb to the chamber and allow gel to cool and solidify for 40 min.
Pipette 7
μL of DNA Ladder and DNA sample with 1
μL of DNA Loading Dye into separate wells.
Run gel at 120 V for 25 min to measure weight of DNA sample against DNA ladder.
LAMP DNA and RNA Amplification
Materials
New England Biolabs WarmStart® LAMP Kit (DNA & RNA)
LAMP Primers
FIP
BIP
F3
B3
Loop F
Loop B
Purified Target RNA
Hydroxy Naphthol Blue (HNB)
Methods
Prepare 10X LAMP primer mix with all primers in a single microfuge tube according to WarmSmart® LAMP Kit protocol.
Store primer mix at -20
°C for 30 min. Vortex primer mix for 5 sec.
Prepare 3 microfuge tubes for positive (all reagents), negative (no RNA template), and negative (no Master Mix). Thaw frozen reagents.
1. MiRNeasy kits. QIAGEN. (n.d.). Retrieved September 30, 2022, from https://www.qiagen.com/us/products/discovery-and-translational-research/dna-rna-purification/rna-purification/mirna/mirneasy-kits/
2. GeneJET genomic DNA purification kit. Thermo Fisher Scientific - US. (n.d.). Retrieved September 30, 2022, from https://www.thermofisher.com/order/catalog/product/K0722
3. GeneJET PCR purification kit. Thermo Fisher Scientific - US. (n.d.). Retrieved September 30, 2022, from https://www.thermofisher.com/order/catalog/product/K0701
4. WarmStart® Lamp Kit (DNA & RNA). New England Biolabs. (n.d.). Retrieved September 30, 2022, from https://international.neb.com/products/e1700-warmstart-lamp-kit-dna-rna