Team:Uppsala/affinity-tags

From 2013.igem.org

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<h3> Keep your plasmids without antibiotic resistance </h3>
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One of the challenges when creating synthetic systems in bacteria that serve a purpose besides increasing the fitness of the organism is that there is a negative selective pressure against keeping the system. Toxin-antitoxin systems can be used to make plasmids far more stabile without having to use antibiotics and antibiotic resistance.  If a clone were to lose the plasmid, the toxin which usually has a longer half life than the antitoxin will kill the bacteria.
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<h3> A natural toxin-antitoxin from lactobacillus plantarum </h3>
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We have taken the Pem toxin-antitoxin system from plasmid p256 that was originally isolated from lactobacillus plantarum NC7. The system consists of a single operon and consists of two ORFs, one for the toxin and antitoxin respectively. Pem on p256 has been shown to increase segregational stability under non-selective pressure. The system has experimentally been shown to allow 88-100% retention of a plasmid after 80 generations(1). We have provided the toxin-antitoxin system both with and without a natural putative promoter.
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<h3> References: </h3>
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http://mic.sgmjournals.org/content/151/2/421.long (1)

Revision as of 21:55, 27 September 2013

Uppsala iGEM 2013

Keep your plasmids without antibiotic resistance

One of the challenges when creating synthetic systems in bacteria that serve a purpose besides increasing the fitness of the organism is that there is a negative selective pressure against keeping the system. Toxin-antitoxin systems can be used to make plasmids far more stabile without having to use antibiotics and antibiotic resistance. If a clone were to lose the plasmid, the toxin which usually has a longer half life than the antitoxin will kill the bacteria.

A natural toxin-antitoxin from lactobacillus plantarum

We have taken the Pem toxin-antitoxin system from plasmid p256 that was originally isolated from lactobacillus plantarum NC7. The system consists of a single operon and consists of two ORFs, one for the toxin and antitoxin respectively. Pem on p256 has been shown to increase segregational stability under non-selective pressure. The system has experimentally been shown to allow 88-100% retention of a plasmid after 80 generations(1). We have provided the toxin-antitoxin system both with and without a natural putative promoter.

References:

http://mic.sgmjournals.org/content/151/2/421.long (1)