Designed by: Kong Yangyang   Group: iGEM21_The_Webb_Schools   (2021-10-09)


The promoter of efeB.


Name: promoter

Base Pairs: 96 bp

Origin: Escherichia coli str. K-12 substr. MG1655

Properties: The promoter of efeB

Usage and Biology

In modern society, more and more people suffer from mild or severe depression. It has been reported that malondialdehyde (MDA) level in the plasma of depressed patients is significantly increased. After receiving conventional antidepressant treatment, the patient's MDA level decreased to the same as that of healthy people. Therefore, researchers believe that oxidative stress may play an important role in the occurrence and development of depression, and the activity of antidepressant therapy may be mediated by improving oxidative stress/antioxidant function. We attempt to express an antioxidant enzyme system (peroxidase gene efeB) in the cell or on the surface of the engineered probiotic bacteria to inhibit the production of malondialdehyde (MDA) by human cells and prevent cell oxidation from causing health damage to the body. So as to prevent or alleviate the condition of depression. The oxidation rate of peroxisome increases in proportion to the increase of oxygen tension. Especially in the case of high oxygen concentrations, the oxidation reaction of peroxisomes dominates. This characteristic allows peroxisomes to protect cells from the toxic effects of high concentrations of oxygen. efeB reduces the oxidative stress in the cell by competing with mitochondria for oxygen, and reduces the MDA produced during the oxidation of lipids.

Figure 1. Action and function of efeB in MDA reduction...

The growth of engineering bacteria under H2O2 treatment conditions

Figure 2. Line chart of the OD600 of bacteria A, C and D against hours in 2.5mM H2O2...

The bacteria A contains plasmid A, pUC57-efeB. The bacteria C contains plasmid C, pUC57-efeB-amilGFP. The bacteria D contains plasmid D, pUC57. The bacteria are placed in 2.5mM hydrogen peroxide and their growth is measured for the first 4 hours. Bacteria D, without the efeB gene, has lower growth than bacteria A and bacteria C. This shows that efeB gene helps bacteria to grow when ROS is present.

MDA and Fluorescence Measuring

Figure 3. Histogram of MDA in the systems with different H2O2 concentration of bacteria A, C and D...

Bacteria A, C, D were placed in hydrogen peroxide solution for 21 hours and the concentration of MDA was measured. Bacteria A and C kept the MDA concentration dramatically lower than those of Bacteria D under the hydrogen peroxide concentration of 0mM, 2mM and 2.5mM. There is a certain amount of MDA concentration within DH5α when the H2O2 concentration is 0mM. Starting from the original DH5α MDA concentration to the higher MDA concentration imposed by the 2mM and 2.5mM H2O2 concentration, Bacteria A and C with the efeB gene all effectively reduced the MDA concentration to the level lower than Bacteria D.


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[3] Wang, J., Wu, X., Lai, W., Long, E., Zhang, X., Li, W., Zhu, Y., Chen, C., Zhong, X., Liu, Z., Wang, D., & Lin, H. (2017). Prevalence of depression and depressive symptoms among outpatients: a systematic review and meta-analysis. BMJ open, 7(8), e017173.

[4] Bueno-Notivol, J., Gracia-García, P., Olaya, B., Lasheras, I., López-Antón, R., & Santabárbara, J. (2021, January 1). Prevalence of depression during the COVID-19 outbreak: A meta-analysis of community-based studies. International Journal of Clinical and Health Psychology. DOI: 10.1016/j.ijchp.2020.07.007.

[5] U.S. Department of Health and Human Services (HHS). (n.d.). Major Depression. National Institute of Mental Health.

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[7] Jiménez-Fernández, S., Gurpegui, M., Dí¬az-Atienza, F., Pérez-Costillas, L., Gerstenberg, M., & Correll, C. U. (2021, March 1). Comparison of ODD vs Healthy Controls.

[8] Rowe, L. A., Degtyareva, N., & Doetsch, P. W. (2008). DNA damage-induced reactive oxygen species (ROS) stress response in Saccharomyces cerevisiae. Free radical biology & medicine, 45(8), 1167–1177.

[9] Jiménez-Fernández, S., Gurpegui, M., Díaz-Atienza, F., Pérez-Costillas, L., Gerstenberg, M., & Correll, C. U. (2015). Oxidative stress and antioxidant parameters in patients with major depressive disorder compared to healthy controls before and after antidepressant treatment: results from a meta-analysis. The Journal of clinical psychiatry, 76(12), 1658–1667.

[10] Li, J., Yang, Z., Qiu, H., Wang, Y., Jian, L., Ji, J., & Li, K. (2020). Anxiety and depression among general population in China at the peak of the COVID-19 epidemic. World psychiatry : official journal of the World Psychiatric Association (WPA), 19(2), 249–250.

[11] Vaváková, M., Ďuračková, Z., & Trebatická, J. (2015, May 20). Markers of Oxidative Stress and Neuroprogression in Depression Disorder. Oxidative Medicine and Cellular Longevity.

[12] Wang Y;Li H;Li T;He H;Du X;Zhang X;Kong J; (n.d.). Cytoprotective effect of Streptococcus thermophilus against oxidative stress mediated by a novel peroxidase (EfeB). Journal of dairy science. DOI: 10.3168/jds.2018-14601

Sequence and Features

Assembly Compatibility:
  • 10
  • 12
  • 21
    Illegal BglII site found at 52
  • 23
  • 25
  • 1000