By Joey Shepherd

In the first study of its kind to show results in living animals, a group headed by Kenneth Shea of Stanford University have developed plastic antibodies that can capture and clear a bee venom peptide, melittin, from the bloodstream of living mice.

The team created the melittin antibodies using a process known as ‘molecular imprinting’ – essentially creating moulds made of non-toxic synthetic organic nanoparticles (NPs) by making the NPs form around molecules of melittin. The melittin was then dissolved away, leaving protein-sized polymer nanoparticles with an imprint of the venom peptide. The NPs were then able to capture the melittin peptides since they were an exact fit, much as naturally occurring antibodies capture their targets.

When the researchers injected the miniscule plastic antibodies into the mice 20 seconds after injecting the bee venom, it resulted in the survival of 60% of the treated mice. In comparison, none of the untreated mice survived injection of the toxin. The group used fluorescence imaging of the live mice to track fluorescently-labelled NPs and found that they accumulated in the liver for disposal after capturing the poisonous peptide from the bloodstream.

Although the plastic antibodies won’t be able to function exactly like naturally occurring antibodies, as they have no means of communicating with other cells of the immune system, they could provide new anti-toxin therapies.

Original paper: Hoshino et al., J.Am.Chem.Soc 132::6644 (2010).

Rhiannon Pursall

Will May 2010 be heralded as a milestone when the so-called ‘miracle of life’ was recreated by a boffin in a lab coat with four bottles of chemicals? Will we soon witness armies of specially designed creatures, cleaning up our oil spills and making medicine? Has the world of biology secured an almighty up-man-ship on that of robotics? 

Dr. Craig Venter and colleagues at the J. Craig Venter Institute, Maryland, USA, have created what has been dubbed the first “synthetic life form”. Which is what, then? In a nutshell, a genome (a kind of biological instruction booklet) was created on a computer and put into a cell. This cell was then controlled by the synthetic instructions, and reproduced to make more cells.

For over a decade, the Venter squad have been testing, developing and perfecting the process that ultimately yielded the ‘synthetic life’ breakthrough. They have worked with various types of the bacterium Mycoplasma, a very useful organism for geneticists as it is relatively simple. It is comprised of the smallest set of genes of any known life form that can be maintained in the laboratory – and so serves as an excellent place to start before moving onto bigger life forms. 

Firstly, the researchers grew the instructions that they designed (the ‘synthetic genome’) using a part of genetic machinery taken from yeast. They then ‘booted up’ the instructions in a bacterium. They stressed their method was revolutionary because it began by creating a synthetic genome on the computer, then worked up to making this genome control an organism. In contrast, other genetic engineering processes, such as genetic modification of plants, alter existing genomes.

The end result of Venter’s project is somewhat underwhelming to one hoping for little alien creatures akin to the London Olympic mascots. Contrary to rumour, “new life” was not made: they did not construct an artificial body controlled by totally new genes. They arranged an existing set of genes in a slightly different order, and put them into a pre-existing body. The name says it all – far from futuristic and techie, the new organism is disappointingly referred to as “Mycoplasma mycoides JCVI-syn1.0”…aka simply a form of the bug Mycoplasma mycoides, which infects goats. 

In their article in Science, Venter’s team admit they started small in terms of their chosen biological organism, but it is the lessons learned and techniques developed that are something to get excited about. Such progressions could in the future bring the idea of creating ‘useful’ living beings closer to reality. So the project should neither be dismissed as a fuss over nothing nor proclaimed the start of humans “playing god”. It is simply a great example of the scientific process: an idea was formed, and through years of hard work something remarkable was unearthed, serving as a platform for a multitude of research to further progress the idea.  

Understandably, the results sent thunderous alarm bells ringing, notably the fear that new life forms released upon Earth could have catastrophic effects. At the extreme end are somewhat exaggerated ideas such as “one mistake in a lab could lead to millions being wiped out by a plague, in scenes reminiscent of the Will Smith film I Am Legend” (The Daily Mail, 21st May 2010). Pause for thought: given that this research was “thwarted for many weeks” by getting a single unit wrong, in a gene made up of over a million units, accidentally producing some killer superbug that can live and breed seems highly unlikely. 

The scientists behind this important landmark project have been represented as evil conspirators by some – according to Dr David King of the watchdog Human Genetics Alert, “what is really dangerous is these scientists’ ambitions for total and unrestrained control over nature” (The Daily Telegraph, 20th May 2010). Another pause for thought: ‘unrestrained’ is very doubtful to be used to describe future work in this field, with the plethora of ethics hurdles faced by researchers. Also, haven’t science’s previous ambitions to gain “control over nature” lead to some pretty amazing feats, such as fertility treatment and organ transplant? Of course, concerns are very real, valued, and deserve attention. President Obama said that Venter’s work raises, as yet unspecified, “genuine concerns” and has ordered the White House bioethics committee to conduct a review on synthetic biology (New York Times, 20th May 2010).

The next steps are to make instructions for bacteria to make a vaccine. This could herald the beginnings of something amazing, and in Venter’s words, “we are limited mostly by our imaginations”. 

For now, let us dilute the hysteria with a touch of reality: no one knows how complicated the next stage will be, or how long it will take. Considering it took 15 years to make the pioneering footstep, Frankenstein-esque creations are unlikely to be breaking free from laboratories and throwing the natural world into chaos just yet.

The original work is published by Daniel Gibson et al. in the May 20th edition of Science Express and will appear in an upcoming print issue of the peer-reviewed journal Science.