Team:Newcastle/Swarming

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Latest revision as of 00:29, 26 October 2010

Swarming

Our project requires Bacillus subtilis 168 to swarm along the cracks to the site of repair. However it is known that the domesticated Bacillus subtilis 168 is not unable to swarm on a solid surface eg. agar plate, while the undomesticated Bacillus subtilis 3610 exhibit swarming properties (Figure 1). The swarming properties requires two factors, the flagella, which serves as a propeller to push the bacteria forward. And the production of surfactin, which is a natural surfactant which helps in reducing surface tension. In B. subtilis 168, both genes that are involved in the process, swrA and sfp have undergone frameshift mutation, therefore they are defective. As such, our team have decided to repair the genes by designing a biobrick that contain both genes.

Figure 1: Agar plates are inoculated with either B. subtilis 168 (left) or B. subtilis 3610 (right) and incubated overnight at 37°C.

Swarming part

The swarming biobrick consists of the sfp and swrA gene under a constitutive promoter, Pveg. The expression of sfp would allow the post translational modification of the immature surfactin peptide encoded by the srfABCD operon. The mature surfactin is then transported out of the cell, to reduce surface tension. The swrA gene helps in the biosynthesis of flagellum. swrA acts on the the gene sigD, which in turn acts as a transcription for the genes required in the late flagellum biosynthesis. Together, surfactin and the flagella will allow swarming to occur.

This part is [http://partsregistry.org/wiki/index.php?title=Part:BBa_K302016 BBa_K302016 on the parts registry].

Bibliography

Julkowska, D, Obuchowski, M, Holland, IB & Se, SJ 2005, "Comparative Analysis of the Development of Swarming Communities of Bacillus subtilis 168 and a Natural Wild Type : Critical Effects of Surfactin and the Composition of the Medium." Society, vol. 187, no. 1, pp. 65-76.
Kearns, DB & Losick, R 2004, "Swarming motility in undomesticated Bacillus subtilis." Molecular Microbiology, vol. 49, no. 3, pp. 581-590.
Kearns, DB, Chu, F, Rudner, R & Losick, R 2004, "Genes governing swarming in Bacillus subtilis and evidence for a phase variation mechanism controlling surface motility." Molecular microbiology, vol. 52, no. 2, pp. 357-69.

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 ==Swarming==
-It is known that ''Bacillus subtilis'' (strain 168) which is generally used in the lab is unable to swarm on a solid surface eg. agar plate. This is because of two reasons which are:
-# Surfactin is a natural surfactant which helps in reducing surface tension and aids the bacteria to swarm on a solid or semi-solid medium. Strain 168 is unable to produce the bacterial cyclic lipopeptide surfactin.
-# Strain 168 is also unable to biosynthesize flagellum and thus has a very low amount of swarming.
-===''sfp''===
+Our project requires ''Bacillus subtilis'' 168 to swarm along the cracks to the site of repair. However
-Strain 168 is unable to produce surfactin because it contains a frameshift mutation in the gene named ''sfp''. In a non domisticated strain 3610, ''sfp'' gene is intact and thus produces a protein which helps in the post translational modification of the immature surfactin peptide formed by the ''srf''ABCD operon. After the modification, this peptide is exported out of the cell and helps in breaking the surface tension and aids the movement of the bacteria.
+it is known that the domesticated ''Bacillus subtilis'' 168 is not unable to swarm on a solid surface eg. agar plate, while the undomesticated ''Bacillus subtilis'' 3610 exhibit swarming properties (Figure 1). The swarming properties requires two factors, the flagella, which serves as a propeller to push the bacteria forward. And the production of surfactin, which is a natural surfactant which helps in reducing surface tension. In ''B. subtilis'' 168, both genes that are involved in the process, ''swrA'' and ''sfp'' have undergone frameshift mutation, therefore they are defective. As such, our team have decided to repair the genes by designing a biobrick that contain both genes.
-===''swrA''===
+[[Image:Newcastle_swarming.jpg|centre|400px]]
-In the undomesticated strain 3610, the gene ''swrA'' along with the gene ''swrB'' helps in the biosynthesis of flagellum. ''swrA'' acts on the the gene ''sigD'' which acts as a transcription for the genes required in the late flagellum biosynthesis. The laboratory strain 168 contains a fameshift mutation in the gene ''swrA'' and thus the stain moves on the surface with a very slow pace.
-===''swrC''===
+'''Figure 1:''' Agar plates are inoculated with either ''B. subtilis'' 168 (left) or ''B. subtilis'' 3610 (right) and incubated overnight at 37°C.
-It provides resistance to the antimicrobial action of the peptide surfactin.
-===''efp''===
+===Swarming part===
-''efp'' stands for Elongation Factor P and this gene helps in the non dendritic swarming.
-===Pathway===
+[[Image:Newcastle Swarming biobrick.png|centre]]
-Swarming of the colony cells starts when the concentration of the signalling peptide ComX and the pentapeptide pheromone CSF (encoded by ''phrC'') reach a critical concentration and activates the sensor kinase ComP by phosphorylating it. ComP is a part of two component transduction system and thus activates response regulator ComA which is present downstream to ComP.
-ComA targets ''srf'' operon which consists of four genes viz ''srf'' ''A,B,C,'' and ''D'' and it also targets ComS which is present upstream to the ''srf'' operon and it activates competence by displacing MecA from ComK and thus MecA is targeted for proteolysis by ClpC/ClpB. ComK regulates the genes required for competence.
-While ComA is activating ''srf'' operon, another gene named ''sfp'' encodes 4' phosphopantetheinyl transferase which is required to activate each of the four surfactin synthases by the post translational modification of Srf A, Srf B, Srf C, and Srf D, which are required for the non ribosomal assembly of the surfactin heptapeptide.
+The swarming biobrick consists of the ''sfp'' and ''swrA'' gene under a constitutive promoter, Pveg.  The expression of ''sfp'' would allow the post translational modification of the immature surfactin peptide encoded by the ''srfABCD'' operon. The mature surfactin is then transported out of the cell, to reduce surface tension. The ''swrA'' gene helps in the biosynthesis of flagellum. ''swrA'' acts on the the gene ''sigD'', which in turn acts as a transcription for the genes required in the late flagellum biosynthesis. Together, surfactin and the flagella will allow swarming to occur.
-Simultaneously, gene ''swrA'' activates the transcription factor ''sigD'' (sigma D) which acts on the genes required in the late flagellum biosynthesis.
+This part is [http://partsregistry.org/wiki/index.php?title=Part:BBa_K302016 BBa_K302016 on the parts registry].
 ===Bibliography===