Team:Shanghai HS United/Basic Parts
Favorite basic part
Part: BBa_K3585005
In E. coli, the presence of glucose inhibits the synthesis of many catabolic enzymes, a phenomenon called "glucose effect" or "glucose inhibition". Studies have shown that overexpression of LacY can eliminate the glucose effect. In this project, we overexpressed lacY protein to achieve simultaneous metabolism of glucose and galactose, thereby increasing the efficiency of degrading galactose.
Support growth of bacteria expressing lacY in galactose
Bacteria with lacY was able to grow using galactose as the unique carbon source in the culture, although the growth rate of the host bacteria is obviously slower than those strains cultured with glucose.
Figure 1. Growth rate of host strains when supplied with different carbon sources. Each of the strains we have a repeat. Glu represents that we use glucose as the carbon source while fermentation; Gal represents that we use galactose as the carbon source while fermentation; GG represents that we use both glucose and galactose as the carbon source while fermentation; 1917 represents wild type strains; pButy represents that the host strain contained pMTL83151-J23100-butyrate plasmids and expressed butyrate synthesis gene cluster; placY represents that the host strain contained p15A-J23200-lacY plasmids and expressed lacY gene; 1 and 2 represent for sample repeats.
Accelerate consumption rate of galactose
When the medium contained only galactose, the host bacteria expressing lacY gene began to consume lactose at 4 hours, indicating that lacY gene could promote the consumption of galactose by the host bacteria.
Figure 2. Consumption rate of galactose. Each of the strains we have a repeat. Gal represents that we use galactose as the carbon source while fermentation; GG represents that we use both glucose and galactose as the carbon source while fermentation; 1917 represents wild type strains; pButy represents that the host strain contained pMTL83151-J23100-butyrate plasmids and expressed butyrate synthesis gene cluster; placY represents that the host strain contained p15A-J23200-lacY plasmids and expressed lacY gene; 1 and 2 represent for sample repeats.
Part: BBa_K3585001
The basic part BBa_K3585001 is a new part in the registry parts. The biosynthetic gene cluster contains all enzymes in the synthesis pathway from galactose to butyrate, that can degrade galactose and synthesize butyrate.
Accelerate consumption rate of glucose
When cultured with glucose as the carbon source, the glucose was almost run out till cultured for 8 hours. When the culture medium contained glucose and galactose, the carbon source consumption rate was lower than that of the culture medium containing only glucose. However, the bacteria had butyrate synthesis gene, the consumption rate of glucose was accelerated.
Figure 3. the concentration of glucose when supplied with glucose. Note: each of the strains we have a repeat. Glu represents that we use glucose as the carbon source while fermentation; GG represents that we use both glucose and galactose as the carbon source while fermentation; 1917 represents wild type strains; pButy represents that the host strain contained pMTL83151-J23100-butyrate plasmids and expressed butyrate synthesis gene cluster; placY represents that the host strain contained p15A-J23200-lacY plasmids and expressed lacY gene; 1 and 2 represent for sample repeats.
Wechat: Search "iGEM GalAcid团队" in WeChat