Difference between revisions of "Team:CHINA CD UESTC/Design"

After a review of the relevant literature, we learned that in the previous bio-fuel cells, the applications of enzyme fuel cell is very wide, and magnetotactic bacteria can generate the magnetosome attracted by magnet ^[1] . Thereby, we came up to the laccase with oxidation, which can be put into the cell cathode and better immobilized by magnetosome. At the same time, we hope to use the reporter gene RFP to help locate and content the mamW protein visualized. According to the principle of co-transformation ^[2] , we designed the vector piGEM-pACYCDuet-1-laccase-mamW-RFP, and we put together the genes of laccase + mamW + RFP to the vector.

The main role of each gene as follows:
(1) laccase: Efficient oxidase, catalyzes the substrate to produce electrons, which can be used as a biological cathode in enzyme fuel cell and applied in batteries.

(2) mamW: The main function is membrane localization, found in magnetic bodies outside the membrane vesicles, which can help laccase immobilization. And mamW is related to the formation of magnetosome.

(3) RFP: The reporter gene, which protein can locate and content the mamW protein visualized out of the vesicle membrane, while the contents and expression of laccase.

Wherein, mamW gene was amplified from the MSR-1 extracted genomic by PCR. Laccase gene was obtained from BBa_K863005 on the 2015 Kit Plate2. While the RFP gene was taken from BBa_E1010 on the 2015 Kit Plate3.

After constructing this vector completely, we encountered some troubles. Detecting by ABTS method ^[3] , the three genes laccase + mamW + RFP did not work as we expected.Thus, we had designed three other vectors in order to validate our initial vision contain the following genes:

(1) laccase + RFP: Visualizing the expression situation and contents of laccase by RFP.

(2) mamW + RFP: Visualizing the contents and specific location out of the vesicle membranes of mamW protein by RFP, and verified whether mamW protein play a major role in the formation of magnetosome or not.

(3) mamW + laccase: fixed the expressional laccase in the cell cathode and verified whether mamW protein play a major role in the formation of magnetosome or not.

Reference

[1]Serge Cosnier, Michael Holzinger, Alan Le Goff (2014). “Recent advances in carbon nanotube-based enzymatic fuel cells.” Bioengineering and Biotechnology 2:45, doi: 10.3389/fbioe.2014.00045

[2]Zhang Peng (2007). “Test method for the laccase activity with ABTS as the substrate.” China Academic Journal Electronic Publishing House 24:1

[3]Isabel Kolinko, Anna Lohße, Sarah Borg, et al. (2014). “Biosynthesis of magnetic nanostructures in a foreign organism by transfer of bacterial magnetosome gene clusters.” Nature Nanotechnology 9: 193-197, doi:10.1038/nnano.2014.13

In order to further study the formation mechanism of the magnetosome’s shape and size, and control them, we constructed the vector piGEM-pCDFDuet-1-mamGFDC-mms6-mamXY which including three important operons of magnetosome: mamGFDC, mms6 and mamXY.

Previous study have shown that although the exact mechanism is not completely understood, these three operons are indispensable in modifying the formation of the magnetosome. Therefore, we built them on one vector to explore its practical effect modification ^[1]. Currently already known as following:

In brief, magnetosomes produced by magnetotactic bacteria cannot form a chain without those three operons, which will extremely affect its magnetotaxis. So we decided to componentize the genes of this part. And finally we submitted two parts of related genes which are BBa_K1779100 and BBa_K1779101.

We chose pCDFDuet-1 as our vector, mainly for the following three considerations:

The final design of vector is shown in the following figure:

(1) laccase + RFP: Visualizing the expression situation and contents of laccase by RFP.

Meanwhile, in order to solve the problem that gene is too large to be directly obtained, we decided to get two gene fragments mamXY and GFDC + mms6 from MSR-1 genome. We respectively designed the method of gene obtain shown in the following figure. The last one, mamW was connected on the vector pCDFDuet-1.

As we preliminary verified our vector by means of enzyme digestion and sequencing, the results have shown that we have successfully connected the two gene fragments, and the vector was successfully constructed.

Reference

[1]Ana Carolina V. Araujo; Fernanda Abreu; Karen Tavares Silva; Dennis A. Bazylinski; Ulysses Lins. Magnetotactic Bacteria as Potential Sources of Bioproducts.Mar. Drugs 2015,13,389-430

[2] Scheffel, A.; Gärdes, A.; Grünberg, K.; Wanner, G.; Schüler, D. The major magnetosome proteins MamGFDC are not essential for magnetite biomineralization in Magnetospirillum gryphiswaldense but regulate the size of magnetosome crystals. J. Bacteriol. 2008, 190, 377–386

[3] Lohße, A.; Ullrich, S.; Katzmann, E.; Borg, S.; Wanner, G.; Richter, M.; Voigt, B.; Schweder, T.; Schüler, D. Functional analysis of the magnetosome island in Magnetospirillum gryphiswaldense: The mamAB operon is sufficient for magnetite biomineralization. PLoS One 2011, 6, doi:10.1371/journal.pone.0025561

[4] Ding, Y.; Li, J.; Liu, J.; Yang, J.; Jiang, W.; Tian, J.; Li, Y.; Pan, Y.; Li, J. Deletion of the ftsZ-like gene results in the production of superparamagnetic magnetite magnetosomes in Magnetospirillum gryphiswaldense. J. Bacteriol. 2010, 192, 1097–1105

[5] Murat, D.; Quinlan, A.; Vali, H.; Komeili, A. Comprehensive genetic dissection of the magnetosome gene island reveals the step-wise assembly of a prokaryotic organelle. Proc. Natl. Acad. Sci. USA 2010, 107, 5593–5598