Team:XHD-Wuhan-Pro-China/Human Practices
Integrated Human Practices
At the beginning of our project, in order to better understand the impact of drinking on people, we looked through relevant studies and reports. According to a 2020 survey, in Wuhan alone, passive drinking for work and social activities was the most dangerous influencing factor on people’s consumption of alcohol. (Figure 1) In WHO’s Global Status Report on Alcohol and Health from 2018, it is stated that in China, 2016, 62.6% of the deaths in male and 41.6% of the deaths in female due to liver cirrhosis were alcohol -attributable (Figure 2). This told us, a group of high school students who want to solve this problem, that people can't avoid drinking even if alcohol seriously harms the body. That is why it's so urgent to solve the problem. However, simple education and propaganda cannot directly help people reduce or even avoid the physiological harm of alcohol. On the other hand, education will not change China's drinking culture and society’s mainstream opinion towards alcohol overnight, not to mention that many people are dependent on alcohol According to WHO, 2.3% of Chinese in 2016 have alcohol dependence (Figure 3). After understanding the background and limitations of current solutions, our team wanted to develop a new solution to cope with the issue of alcohol poisoning in China and around globe.
Higher the OR, the more dangerous the influencing factor is Figure 1
Figure 2
Figure 3
Due to the limited knowledge reserve of high school students, although we have found a breakthrough to solving this problem, we don't know how to make the antidote. Therefore, we consulted Dr. Gao from Wuhan Tongji hospital. He told us that the reason why there are good and bad drinkers is that some people cannot completely metabolize harmful substances such as ethanol and acetaldehyde as they lack alcohol and aldehyde dehydrogenase. We can solve this problem by increasing alcohol and aldehyde dehydrogenase in the body by directing taking in the enzyme through month.
To verify and understand the relevant information of the suggestions given by Dr. Gao, we have done more background researches. When considering the credibility of doing so. We found that we need to recombine and purify protein first if the enzymes are to be ingested directly, which is a very laborious and time-consuming process. At least one month would be required, and the time needed could extend up to half a year. Moreover, the enzyme will denatured in the low pH environment in stomach.
We then visited another expert-Dr. Yang from Wuhan Union hospital. After understanding the problems we encountered, she gave some advice for our reference: we could use genetically modified probiotics to produce alcohol and acetaldehyde dehydrogenase in the human small intestine. In this way, the recombination and purification of protein would not be needed, and the enzymes will not be in contact with the gastric acid when passing through the stomach. Additionally, as we planned to let the probiotic to be ingested orally, she recommended us to use E.coli Nissle 1917 as our probiotic due its high safety.
While we were verifying the suggestion through experiment subsequently, the ratio of NAD+/NADH would fall if the intake of alcohol is too high as NAD+ will be converted into NADH in large amount. As a result, the metabolic ability of alcohol and acetaldehyde dehydrogenase would fall due to insufficient energy supply to the reactions.
To solve our new problem, we interviewed a third expert: Professor Ma from Huazhong Agriculture University. He pointed out that NADH oxidase (NOx) can play the role to remove the obstacles in NAD+ replenish and introduce a nad gene to express NAD synthase. Amit (NAad) into NAD (H), and increase the capacity of NAD (H) storage, so the level of NAD + / NADH will maintain balance. Therefore, we added nadE and NOx genes when iterating the gene circuit.
We also went to BGI for field investigation. BGI has rich experience in the production of various oral probiotic products. After listening to our project introduction, the researchers there proposed that since we planned to take probiotics before taking alcohol, when the alcohol concentration might be too high, the probiotics would be in an environment with high ethanol and high acetaldehyde concentration, and their growth and metabolism would be inhibited, Therefore, the degradation function could be performed normally. Considering this problem, we added to our design an experiment to test ethanol and acetaldehyde tolerance of the engineered bacteria.
Reference:
1. Poznyak, :., 2018. WHO Global status report on alcohol and health 2018.
2. Liu, S., 2020. Analysis of drinking status and influence factors among migrant population, urban residents and rural residents in Wuhan. Modern Preventive Medicine, 47(10).