The BioCrew’s 2021 Project

Our project aims to reduce the effects depression and anxiety. We’ll utilize human genes, clone them into plasmids, place them into their specific bacterial cells, and see if they now express the proper proteins necessary for an increase in serotonin production. We will insert TPH1 (tryptophan hydroxylase) into bacteria which will make 5HTP, which is main amino acid in serotonin production; serotonin helps with depression and anxiety. All genes were codon optimized for E. coli, and we removed the 4 restriction sites that we don’t want in our genes: XbaI, SpeI, EcoRI, and PstI. We’ll develop the bioengineered product into a probiotic that can be ingested to improve mental health. 

Safety in our Genetic Engineering and Synthetic Biology Project


What organisms are we using and are they safe? 

We plan to engineer either Lactobacillus helveticus R0052, E. coli Nissle, or other Lactobacillus strains. Lactobacillus helveticus R0052 is an oxygen-tolerant anaerobe and it must be grown at 37 degrees Celsius and in an atmosphere of 5% CO2 because it is normally found in the gut and the intestines. This means that it is unlikely to be able to grow outside of these conditions. One safety concern in the lab about our organism is regulating its growth; we need to make sure that our organism replicates at a controlled rate. The system won’t produce any known toxins since these are over-the-counter products.  

We can also engineer Lactobacillus rhamnosus since it’s normally found in gut and intestines and is oxygen tolerant, which means the conditions for growth are doable in the lab.  We chose to use E. Coli and Lactobacillus since they’re bacteria that are already being used as over the counter probiotics and are naturally existing, so they should be considerably safe to use.

What risks could they pose to our community or the environment if they escape the lab?

Lactobacillus is listed at Biosafety Level 1 meaning that it does not regularly cause disease in people. The continued development of the project would not require environmental release since our experiments focus on bacterial subjects. We hope to get the product ready for animal testing and human trials, but we wouldn’t actually test on animals and people ourselves; we’ll focus on the entrepreneurship aspect and how we’d market our product. Instead of testing on people, we can use the gut-on-a-chip which simulates an actual gut by creating multiple groves and canals containing human cells in a controlled biochemical environment. With this we would be able to simulate how our project would react in the gut and further research the effectiveness of our engineered probiotic without compromising the safety of the a test subject.


What risks could arise from our experiments?

Conducting the experiments could potentially create health risks from the consumption of the products, therefore extensive trials should be conducted in order to evaluate potential long-term and short-term health risks. The project should also adhere to policies of containment to reduce exposure to biological material.  Lactobacillus has risks of endocarditis and other infections associated with weak immune systems, therefore precautions should be taken to reduce risk of contamination and transmission of biological material to people who could be susceptible.

We also need to worry about the overproduction of serotonin, which is called serotonin syndrome. To combat this, we’ll use a promoter from a previous team to control expression. We can also continue to prioritize safety by working to build a negative feedback system and use math modeling to estimate how much serotonin would be produced by determining the rate of disappearance of bacterial L-tryptophan from the body as its used to make 5 HTP, the precursor for serotonin.


How will we manage the risks?

Proper training and enforcement of procedures will help create greater accountability for our and will minimize health risks. While conducting procedures under a biosafety level 1, we should continuously emphasize biosafety health practices, especially when handling the psychobiotic chemicals like serotonin. We can conduct a Local Risk Assessment in order to determine the toxicity of substances and potential health risks.

We have been trained and will practice standard biosafety procedures, including washing hands after working with material, decontaminating surfaces, handling and disposing of all material in proper waste disposal containers. Food and drinks should also be prohibited within laboratory areas. All individuals should be provided appropriate personal protection equipment. Prior to conducting the experiments, proper laboratory designs and procedures should be fully enforced.