# InterLab Study

This year, The iGEM Foundation invited us to participate in the Interlab Study and we agreed to take part in it. In the study, iGEM teams gather fluorescence data for three GFP expressing devices around the world using the same methods for cloning and measurements. The goal of this international experiment is to find out, how precisely organisms act the same in the different parts of the world if they contain similar genetic material. Our InterLab Study Lab Book can be found here for a fully detailed overview of our study.

## Devices

The following devices were created in a backbone pSB1C3:

⚫ J23101 + I13504 (B0034-E0040-B0015)
⚫ J23106 + I13504 (B0034-E0040-B0015).

However, constructing a device J23117 + I13504 (B0034-E0040-B0015) wasn't successful due to the time limit and limited ligation times. More details available on Lab Book. The device sizes were analyzed with restriction mapping and the results can be seen in Figure 1.

Used BBa_I20270, a GFP expressing part in the pSB1C3 backbone as a positive control. Negative controls were organisms with an empty plasmid and without any vector.

## Protocols

### Constructing devices

Protocols for the restriction, ligation and transformation of BioBricks can be found here.

### Cultivations and measurement

Followed the next protocol for preparing the samples:

Streaked out LB-plates with E. coli TOP10 strain containing every device and control with chloramphenicol concentration of 35 μg/ml. Incubated plates overnight (18-20 hours) at 37$$^\circ$$C. Picked up biological triplates from the plates and inoculated 3 ml liquid cultures from the colonies with 12 ml polypropylene test tubes. Incubated the tubes at 37$$^\circ$$C with shaking at 300rpm for 18 hours. Measured OD600 values of cultures in cuvettes and calculated the dilution required for each sample to obtain the OD value of 0.5. Diluted and re-measured the samples to reach 5% accuracy of 0.5. Transfered 200 μl of each sample into 96-well transparent plate and set the platereader to read fluorescence intensity. Proceeded with the measurements with the following equipment:

Type: Cell Imaging Multi-Mode Plate Reader
Name and model: Cytation 3
Company: BioTek Instruments, Inc

The following parametres were used:

Excitation wavelength: 470 nm
Emission wavelength: 511 nm
Optics Position: Bottom
Filter: Quadruple Monochromators with Bandwith of 16 nm
Units Reported: RFU

## Results

The measurements were partially successful. Results can be seen in tables below. The data hasn't been processed further and the units are in Relative Fluorescence Units.

Most samples generated overflow values which could not be measured with the plate reader. The incubation may have generated too much fluorescent proteins even though the samples were diluted properly. The problem wasn't solved after new dilutions of 9:10 ratio and due to the time limit, other ratios weren't attempted. The first blank value is with antibiotics and the second without for the negative control without any plasmids.

1

OVRFLW

83954

53925

16309

13663

29336

2

OVRFLW

OVRFLW

56764

16335

14148

14940

3

OVRFLW

OVRFLW

61918

16771

14073

1

OVRFLW

85224

53553

16307

13747

29470

2

OVRFLW

OVRFLW

56472

16204

14267

14972

3

OVRFLW

OVRFLW

60969

16818

14381

1

OVRFLW

86750

56390

16123

13536

30778

2

OVRFLW

OVRFLW

58294

16294

14207

14856

3

OVRFLW

OVRFLW

62229

16793

13994

## Validation

The gel electrophoresis mapping of J23101 + I13504 and J23106 + I13504 can be seen in Figure 1 where the outermost bands belong to ladders. Both the samples (in the middle) should have the same size (2989 bp). The bands belonging to constructs seem to be slightly bigger (~3000 bp) than expected but it is hard to say if the ladders have a bit of inaccuraty.