Team:ZJUT-China/InterLab

INTERLAB

Our team participated in the Fifth International InterLaboratory Measurement Study this year. The interlab study aims to solve the problem of reliability and repeatability in synthetic biology study. This year we were asked to measure green fluorescent protein, which is used as a measurement marker. We followed the experiment protocol strictly to make sure our data is valid. After two weeks lab work, we got the data we need after several attempts.

Calibration Protocol

Three calibration measurement were done by the calibration protocol, including an OD reference point at 600nm, one particle standard curve and one fluorescent standard curve.

(Plate Reader: Molecular Device, Spectramax M5)

★ OD600 reference point ★


LUDOX CL-X H2O
Replicate 1 0.066 0.0285
Replicate 2 0.059 0.029
Replicate 3 0.068 0.026
Replicate 4 0.064 0.028
Arith. Mean 0.064 0.028
Corrected Abs600 0.036
Reference OD600 OD600
OD600/Abs600 1.728
Form1.OD reference point

Particle_Standard_Curve.png Fig1.Particle standard curve
Particle_Standard_Curve_(log_scale)e Fig2.Particle standard curve (log_scale)


Fluorescein_Standard_Curve Fig3.Fluorescein standard curve
Fluorescein_Standard_Curve_%28log_scale%29 Fig4.Fluorescein standard curve (log_scale)

Cell measurement

Transformation

Transform Escherichia coli DH5α with these following plasmids:

Device Part Number Location
Positive control BBa_R0040 Well 2D
Negative control Ba_I20270 Well 2B
Test Device 1 BBa_J364000 Well 2F
Test Device 2 BBa_J364001 Well 2H
Test Device 3 BBa_J364002 Well 2J
Test Device 4 BBa_J364007 Well 2L
Test Device 5 BBa_J364008 Well 2N
Test Device 6 BBa_J364009 Well 2P
Form2.Devices (from Distribution Kit, all in pSB1C3 backbone)

The transformation used E.coli DH5α competent cells bought from Tsingke Biological Technology company, and follow the steps in http://parts.igem.org/Help:2017_DNA_Distribution to use the DNA in the Distribution Kit.

Measurement


For this part of inter lab study, we followed the following protocols:

1.Grown 8 devices in incubator for 12 hrs at 37 ℃
2.Pick 2 colonies from each of plate and inocubate them on 10mL LB medium with Chloramphenicol. Grow the cells for 16-20hrs at 37°C and 180rpm.
3.Measure OD600nm of the overnight cultures and record the data, then dilute to target OD600nm = 0.02 in the falcon tubes.
4.Measure the OD600nm and Fl under the same condition as standard curve measurement and use the same 96 wells plates.


plate_lay_out
Fig5. plate lay out

★ Fluorescence Raw Readings:★

Fluorescence Raw Readings

★ Abs600 Raw Readings:★

Abs600 Raw Readings

★ uM Fluorescein / OD ★

uM Fluorescein / OD

★ Net Fluorescein a.u. ★

Net_Fluoresceina.u.

★ Net Abs 600 ★

Net_Abs_600
Form3-6. Result of Raw Plate Reader Measurements

CFU Protocol

For this part of inter lab study, we followed the following protocol:

1.Pick two colonies from positive control device and negative control device, incubate overnight.
2.Prepare Starting Samples: Dilute the overnight cultures 1:8, measurement then dilute further to OD600nm = 0.1
Calculation:
Use (C1)(V1) = (C2)(V2) to calculate your dilutions C1 is your starting OD600   C2 is your target OD600 of 0.1
V1 is the unknown volume in μL   V2 is the final volume of 1000 μL
3.Check and make sure OD600 = 0.1
4.Dilute Dilute
5.Incubate at 37 degree Celsius overnight for 18-20 hrs. Then count colony number.
colony_number