A team of TU Delft students has developed bacteria that engage in relay races. In late October, the team will present their invention during the International Genetically Engineered Machines competition, held at MIT.
‘Hi there neighbor, have some of my DNA.’ This may seem strange coming from bacteria, if only because bacteria don’t have sex. But they do exchange DNA, however, by making temporary, bridge-like connections between one another through which they transfer genetic material, often in the form of small, circular pieces of DNA, called plasmids.
This exchange mechanism is a handy tool for the bacteria (and a curse for humanity), helping them to spread resistance against antibiotics, among other things. But by genetically engineering plasmids, one can also make the bacteria do crazy stuff, like passing on a gene that encodes for a fluorescent protein. At the department of biotechnology (faculty of Applied Sciences), a team of students is making bacteria that pass on light, as if engaging in a relay race.
The invention is one of around 120 entries for the iGEM (International Genetically Engineered Machines) bacteria design competition, which in late October will be held for the sixth time at Massachusetts Institute of Technology (MIT), in Boston. The goal of this event is to design bacteria that are as bizarre as possible, and also, if possible, to develop them using ‘bio bricks’, which are standardized bits of DNA that have known (possible) effects in the cell and can be used as building blocks.
Every year MIT sends hundreds of these bricks to student teams around the world to play with. The students thus help to further develop synthetic biology, a relatively young scientific discipline. Synthetic biology’s ultimate goal is to design life forms, much like engineers design computers or cars.
Needless to say, this is very ambitious, since biochemical processes cranked up by genes all interact with one another in ways difficult to predict. Most scientists believe that making life from scratch is impossible, that one always needs a cell with a few hundred genes to start with.
The record for synthesized life is held by one of the founders of the iGEM competition, synthetic biology guru, Jay Keasling, of the University of California, Berkeley. By adding 20 genes to a bacterial genome, Keasling made bacteria that produce artemisinine, a malaria medicine.
In preceding years, teams competing at iGEM upgraded their bacteria, or thought of many ways of doing so. In 2006, a team from MIT showed that it is indeed possible to make bacteria smell like mint when they’re growing, and like banana when they’ve finished growing. Last year a team from the Catholic University of Leuven (Belgium) designed a bacterium, named ‘Dr. Coli’, which releases medicines in a patient and then self-destructs when the patient is cured. Last year’s TU Delft team worked on a ‘thermometer bacteria’ that becomes red when the temperature rises above 27 °C.
“What we wanted to do above all this year is to develop bacteria with a self-destructive plasmid,” says Saeed Katiraei, one of the student members of this year’s TU Delft team. “That is something new. It also allows us to study cell to cell communications. In order to make a bacterial relay race work, the plasmid with the gene encoding for the fluorescent protein must self-destruct after it has passed a copy of itself on to the next bacteria. Otherwise, the whole bacterial population will become fluorescent and you will no longer be able to follow the trajectory of the genes.”
Unfortunately, the process failed to work. “We tried all different kinds of cloning techniques, but we couldn’t get the genes to work,” Katiraei adds. “The bacteria do however transmit the light signal, and we did manage to add a new bio-brick combination to the list of known bricks. We developed a combination that produces fluorescent proteins but that also contains a delaying mechanism, so that the ‘fluorescent gene’ will only spring into action once it has been completely transmitted to the neighboring cell.”
The team is now racing against the clock to publish all its efforts and results on its wiki.
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‘Hi there neighbor, have some of my DNA.’ This may seem crazy coming from bacteria, if only because bacteria don’t have sex. But they do exchange DNA, however, by making temporary, bridge-like connections between one another through which they transfer genetic material, often in the form of small, circular pieces of DNA, called plasmids.
This exchange mechanism is a handy tool for the bacteria (and a curse for humanity), helping them to spread resistance against antibiotics, among other things. But by genetically engineering plasmids, one can also make the bacteria do crazy stuff, like passing on a gene that encodes for a fluorescent protein. At the department of biotechnology (faculty of Applied Sciences), a team of students is making bacteria that pass on light, as if engaging in a relay race.
The invention is one of around 120 entries for the iGEM (International Genetically Engineered Machines) bacteria design competition, which in late October will be held for the sixth time at Massachusetts Institute of Technology (MIT), in Boston.
The goal of this event is to design bacteria that are as bizarre as possible, and also, if possible, to develop them using ‘bio bricks’, which are standardized bits of DNA that have known (possible) effects in the cell and can be used as building blocks.
Every year MIT sends hundreds of these bricks to student teams around the world to play with. The students thus help to further develop synthetic biology, a relatively young scientific discipline.
Synthetic biology’s ultimate goal is to design life forms, much like engineers design computers or cars. Needless to say, this is very ambitious, since biochemical processes cranked up by genes all interact with one another in ways difficult to predict. Most scientists believe that making life from scratch is impossible, that one always needs a cell with a few hundred genes to start with.
The record for synthesized life is held by synthetic biology guru, Jay Keasling, of the University of California, Berkeley. By adding 20 genes to a bacterial genome, Keasling made bacteria that produce artemisinine, a malaria medicine.
In preceding years, teams competing at iGEM upgraded their bacteria, or thought of many funny ways of doing so. In 2006, a team from MIT showed that it is indeed possible to make bacteria smell like mint when they’re growing, and like banana when they’ve finished growing. Last year a team from the Catholic University of Leuven (Belgium) designed a bacterium, named ‘Dr. Coli’, which releases medicines in a patient and then self-destructs when the patient is cured. Last year’s TU Delft team worked on a ‘thermometer bacteria’ that becomes red when the temperature rises above 27 °C.
“What we wanted to do above all this year is to develop bacteria with a self-destructive plasmid,” says Saeed Katiraei, one of the student members of this year’s TU Delft team. “That is something new. It also allows us to study cell to cell communications. In order to make a bacterial relay race work, the plasmid with the gene encoding for the fluorescent protein must self-destruct after it has passed a copy of itself on to the next bacteria. Otherwise, the whole bacterial population will become fluorescent and you will no longer be able to follow the trajectory of the genes.”
Unfortunately, the process failed to work. “We tried all different kinds of cloning techniques, but we couldn’t get the genes to work,” Katiraei adds. “The bacteria do however transmit the light signal, and we did manage to add a new bio-brick combination to the list of known bricks. We developed a combination that produces fluorescent proteins but that also contains a delaying mechanism, so that the ‘fluorescent gene’ will only spring into action once it has been completely transmitted to the neighboring cell.”
The team is now racing against the clock to publish all its efforts and results on its wiki.
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