Ethics

Public Health

Synthetic biology is a rapidly emerging field, but it is still in a very early stage of its development. It is vital to encourage debate with relevant stock holders and the general public in order to investigate the ethics that arise from this research. Therefore, in this section we aim to discuss the ethics relevant to our project.

PEALS

On the 1st of August, our team had a discussion with the executive director, Professor Janice McLaughlin from Policy, Ethics and Life Sciences (PEALS) Centre regarding ethics and biosafety. She helped us identify the relevant sock holders to our project and brought our attention to some topics that we may wish to explore further.

Agriculture

One of our project sub themes involves inserting L-forms in to plants, visualising them and considering their benefits. These plants include crop plants, therefore this topic may raise concerns regarding agriculture and farming. We are interested in the opinions, ideas or concerns that an agriculture representative may have regarding this topic.

Scientists

The Public

Environmental Safety

There are ethical boundaries associated with modifying plants. GM plants could well outcompete native species, spreading away from farmland and into the wild, becoming weeds and reducing biodiversity. They could also crossbreed with other strains.

Using non-L-form bacteria also has multiple potential pitfalls. Kill switches are never 100% safe as there is always the risk of mutations that turn off these genes, resulting in bacteria able to proliferate freely. L-forms however are incredibly osmotically sensitive, unable to survive outside of plants. Therefore they could be introduced into the environment- if they do leave the plants, they will very quickly pop due to water entering through osmosis, and a lack of a cell wall to counteract the resulting increased internal pressure. We have shown this experimentally using water extracted from soil.

Our BioBrick for turning B. subtilis cell walls on and off could also mutate, the cells regaining their walls regardless of the presence of xylose. However, it would be reasonably simple to produce a similar mutant, in which part of or the entire murE operon has been removed. As our BioBrick controls the expression of this operon the effect should be the same. It would not be feasible for random mutations to mask this, as functions of multiple genes essential to peptidoglycan synthesis would have to be replaced.

The murE operon contains the gene Spovd. Although involved in peptidoglycan synthesis, the product is involved in sporulation. Could our BioBrick have a further effect, inhibiting the ability of B. subtilis to sporulate? We are currently considering methods of exploring this. Sporulated bacteria are very difficult to destroy, able to survive for long periods of time in near-extreme conditions. Our L-forms burst in the harsh conditions which induce sporulation.

Establishing whether our bacteria can survive in the wild is only the first step when considering the safety of releasing plants containing our L-forms into the environment. Could DNA released by burst L-forms be incorporated by other bacteria? If so, what effects could this have? What would happen to animals that ingest plants containing our L-forms?

Although there are naturally occurring L-forms that appear to survive (and indeed subsist) in the human body, our L-forms do not survive in the pH and osmotic conditions found in the stomach and digestive tract. It should also be stressed that our L-forms should be harmless, as the B. subtilis we have modified is. However there are ways in which cell wall free bacteria could be harmful, if they were able to survive harsh osmotic conditions. It has been speculated that L-forms are difficult for the immune system to detect, having lost many of the antigens found on the cell wall. Furthermore, many popular antibiotics, including penicillin, work by targeting the cell wall. L-forms are therefore resistant to these, which would make them quite difficult to kill if not for their inherent fragility.

Future

References