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OUR TEAM
LAB 5 WRITE-UP
SYBR Green Dye
SYBR dye is a molecular dye that has fluorescence qualities in the presence of double stranded DNA but not in water or with single stranded DNA. This dye is used to show the presence of dsDNA.
Single-Drop Fluorimeter
The device shines a LED light through a drop of solution sitting on a hydrophobic surface slide that causes the molecules to stick together instead of the plate a spherical shape.
How the Fluorescence Technique Works
SYBR GREEN I dye is used because it fluoresces in the presence of double stranded DNA. When taking a picture of this the fluoresces is picked up the pixels can be analyzed.
Procedure
Smart Phone Camera Settings
- Type of Smartphone: Droid Razor
- Flash: Off
- ISO setting: 800
- White Balance: Auto
- Exposure:highest
- Saturation:highest
- Contrast: lowest
Calibration
- Distance between the smart phone cradle and drop = 6cm
Experimental Set Up
Solutions Used for Calibration '
| Concentration of 2X Thymus DNA (micrograms/mL) |
Volume of 2X DNA solution(uL) |
Volume of the SYBR GREEN I soluion(uL) |
Final DNA concentration in SYBR green I solution(ug/mL)
|
| 5 |
80 |
80 |
2.5
|
| 2 |
80 |
80 |
1
|
| 1 |
80 |
80 |
0.5
|
| 0.5 |
80 |
80 |
0.25
|
| 0.25 |
80 |
80 |
0.125
|
| 0 |
80 |
80 |
0
|
Placing Samples onto the Fluorimeter
- First using the micropipette, pipette 80 microliters of SYBR Green solution onto the slide in the middle on the first row. Then pipette 80 microliters of the 2X calf thymus DNA solution requested in the same place.
- The blue LED light was focused on the sample on the plate, and positioned so it is in the middle of the black fiber optic.
- The timer was Set on the Smartphone for 10 seconds being placing on the cradle (6cm away), then the lid was closed to the black box and allowing the picture to be taken in complete darkness. This was done twice for every sample
- After the pictures were taken, the micropipette was used to remove the solution off the plate. This was repeated 3 times for every concentration.
Data Analysis
Representative Images of Samples
Droplet with no DNA
Droplet with DNA
Image J Values for All Samples
| Trial Number
|
Final DNA concentration in SYBR Green I solution
|
Area
|
Mean Pixel Value
|
RawintDen of the Drop
|
Rawintden of the background
|
INTDEN
|
| 1 |
0 |
94633 |
79.542 |
7527330 |
602362 |
6924968
|
| 1 |
0.25 |
118200 |
65.825 |
7780550 |
659701 |
7120849
|
| 1 |
0.5 |
107328 |
71.761 |
7701956 |
508440 |
7193516
|
| 1 |
1 |
115140 |
126.899 |
14611201 |
530473 |
14080728
|
| 1 |
2 |
102036 |
141.805 |
14469248 |
625685 |
13843563
|
| 1 |
5 |
98864 |
174.741 |
17769909 |
646348 |
17123561
|
| 2 |
0 |
122547 |
36.617 |
4487295 |
552944 |
3934351
|
| 2 |
0.25 |
122547 |
54.325 |
6657319 |
533710 |
6123609
|
| 2 |
0.5 |
122547 |
77.174 |
9457486 |
568182 |
8889304
|
| 2 |
1 |
122547 |
132.743 |
16267264 |
614826 |
15652438
|
| 2 |
2 |
122547 |
107.147 |
13130574 |
467618 |
12662956
|
| 2 |
5 |
122547 |
154.52 |
16813027 |
485789 |
16327238
|
| 3 |
0 |
109408 |
30.175 |
3301381 |
367028 |
2934353
|
| 3 |
0.25 |
109408 |
43.453 |
4754133 |
450131 |
4304002
|
| 3 |
0.5 |
109408 |
61.553 |
6734393 |
468917 |
6265476
|
| 3 |
1 |
109408 |
93.821 |
10264797 |
529161 |
9735636
|
| 3 |
2 |
109408 |
113.063 |
12369977 |
501564 |
11868413
|
| 3 |
5 |
109408 |
147.703 |
16159888 |
533696 |
15626192
|
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Fitting a Straight Line
PCR Results Summary
| PCR Product Tube Label
|
Average INTDENS value
|
PCR Product Concentration
|
Corrected PCR Product Concentration
|
| Positive Control |
2187513.667 |
0.910428461 |
10.92514153
|
| 541 |
172330 |
-8.873821385 |
-106.4858566
|
| 542 |
131309.3333 |
-9.072987574 |
-108.8758509
|
| 543 |
179070 |
-8.841096901 |
-106.0931628
|
| Negative Control |
154153 |
-8.962075528 |
-107.5449063
|
| 431 |
174222 |
-8.864635224 |
-106.3756227
|
| 432 |
174816 |
-8.861751197 |
-106.3410144
|
| 433 |
124983 |
-9.103703596 |
-109.2444431
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Instructor's summary: You completed 8 PCR reactions in a previous lab. You used the SYBR Green I staining and imaging technique to measure the amount of amplified DNA in each PCR reaction. You used a standard curve (based on known concnetration of claf thymus DNA) to convert INTDEN values into DNA concentration. Your positive control and negative control samples are used to determine the threshold values for determining whether an unknown (patient) sample is truly positive or negative.
Your positive control PCR result was 10.9 μg/mL
Your negative control PCR result was -107.5 μg/mL
Write-in each patient ID and give both a qualitative (what the images looked like) and a quantitative description (μg/mL) of what you observed
Patient 54174 : -107.2 μg/mL
The images were very dark. The droplets were transparent.
Patient 43184 : -107.3 μg/mL
The images were very dark. The droplets were transparent.
Compare each patient's results to the positive control value and the negative control value. Draw a final conclusion for each patient (positive or negative) and explain why you made that conclusion.
Patient 54174 : Negative because the patients results had an average of -107.2 μg/mL while the negative control had a value of -107.5 μg/mL and the positive control had a value of 10.9 μg/mL. Therefore the patient's results were much more similar to the negative control than the positive control.
Patient 43184 : Negative because the patient results had an average of -107.3 μg/mL while the negative control had a value of -107.5 μg/mL and the positive control had a value of 10.9 μg/mL. Therefore the patient's results were much more similar to the negative control than the positive control.
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