Part:BBa_K3598010
Human CathelicidinLL-37
Human Cathelicidin LL-37 is antimicrobial peptides produced by human in response to various pathogenic microbes. It has been shown to possess potent antimicrobial activity against a variety of bacteria.
Experiments and Results
The part is the original sequence of Human Cathelicidin LL-37, we verified its antimicrobial potency through two methods: plate inhibition zones assay and OD600 analysis. In plate inhibition zones assay,wo placed pieces of filter paper soaked with AMP solutions onto plates inoculated with E.coli MG1655 and P.acnes and observing bacteria growth inhibition zones. In OD600 analysis, we added AMP solutions into liquid culture inoculated with the bacteria and measuring OD600 value.
Plate verification Results
From the plates showed in Figure 3& 4,we can easily observe the inhibition zones in areas of direct contact between bacteria and Human Cathelicidin LL-37, while no inhibition zone formed around the filter paper. These results indicate that Human Cathelicidin LL-37 is effective to both E.coli and P.acnes, while would not affect bacteria outside its contact. Additionally, the edge of inhibition zone in E.coli plates wasn't clear, some colonies could survive around it, which means the AMP efficiency to E.coli is not as effective as P.acnes.
OD600 Verification
Then, we verified Human cathelicidin LL-37's ability to kill E. coli MG1655 and P. acnes by adding its solution to liquid culture inoculated with the two bacteria. We set the AMP concentration gradient as 0, 2, 4, 8, 12, 16 mg/L, and measured the OD600 of the E. coli through time. Since P. acnes has a slow growth rate, we only measured OD600 after 48 hours of cultivation.
The results in Figure 4 confirmed our speculation in the plate tesst. The effect of this AMP to E. coli is not particularly good, its inhibition to the bacteria still in the early stage of cell growth even if the concentration rises to 16 mg/mL, and the final OD600 values of the experimental group and the control group's were almost the same.
Although Human cathelicidin LL-37 is not very effective against E. coli, it exhibits strong effect on P.acnes. From the 48 h histogram (Figure 5),efficiency of Human cathelicidin LL-37 is obvious. At the concentration of 16 mg/mL, the OD600 vallue of the control group was 0.27, while the experimental group was only 0.16.
Sequence and Features
- 10COMPATIBLE WITH RFC[10]
- 12COMPATIBLE WITH RFC[12]
- 21COMPATIBLE WITH RFC[21]
- 23COMPATIBLE WITH RFC[23]
- 25COMPATIBLE WITH RFC[25]
- 1000COMPATIBLE WITH RFC[1000]
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