Team:Shanghai HS ID/Model

Shanghai_HS_ID

MODEL

To determine the increase in transformation efficiency of our modified L. casei (KO) compared to the wild L. casei (Wild), we spread our Petri dishes by differing volumes of bacteria solutions and cultured them under identical conditions. At the end of our experiment, we measured their OD₆₀₀.
Additionally, we investigated the optimal conditions for the growth of our modified L. casei using varying volumes of bacteria seed solutions

Table 1. OD₆₀₀ of cultured L. casei

Based on our scatter plots, we utilized a quadratic polynomial equation to construct our model :

Our coding is given below:

“
clear;clc;
v0=[50 100 150];
od10=[0.035 0.289 3.84];
od20=[0.255 1.984 5.21];
p1=polyfit(v0,od10,2)
p2=polyfit(v0,od20,2)
v=[50:150];
od1=polyval(p1,v);
od2=polyval(p2,v);
plot(v,od1,'b','LineWidth',2)
hold on
plot(v,od2,'r','LineWidth',2)
plot(v0,od10,'k*','LineWidth',2)
plot(v0,od20,'g*','LineWidth',2)
hold off
”

Our calculations revealed the constants of the solved quadratic polynomial equations for the KO group and Wild group, respectively.

Table 2. Model results

Sample	p1	p2	p3
KO	0.0007	-0.0938	3.0780
Wild	0.0003	-0.0103	0.0230

Figure 1. Comparison between two fitting curves of KO group(red) and Wild group(blue)

Conclusion

We can see in figure 1 that our modified L. casei displays a significantly higher transformation efficiency than the wild L. casei, especially with less than 100 ul of initial bacteria seed solution.

The equation model visualizing the transformation rate of the modified L. casei (shown below) can be used to analyze the relationship between the volume of the bacteria seed solution used and the final OD₆₀₀ of the cultures. The data model can also assist future expression efficiency tests
With a more elaborate model, we would also be able to manipulate the variables and adjust the volume of the bacteria seed solution for other cultures.

Model for the modified L. casei: f(x) = 0.0003x³ - 0.0103x² + 0.0230