Bronze

1. Competition Deliverables：

    
    • Wiki
    • Project Promotion Video
    • Team Presentation
    • Judging Form
All required materials were submitted before deadlines.

2. Attributions

This year, we've done great work thanks to the hard work of all our members and the sincere aid of our supporters.
    In the wet lab, we devoted ourselves to experiments, and, with the breakthrough of modelling and HP-researching, the original designs have been improved over time and work to better consolidate our project. We got together weekly and monthly to get problems well solved and with the different majors we're good at, corporations contributed a lot.
    Moreover, we earnestly appreciate the help of our professors, society and the iGEM world! We visited professors researching relevant work nearly once a month last semester and performed our project better after learning from them. Also, the local depression-helping group gave us a precious chance to have a friendly talk with the patients and understand their true needs. Besides, we iGEM teams had conferences almost twice a month and we got special inspiration every time.
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3. Project Description

    Depression is a common mental disorder that seriously affects people's work and daily life and the diagnosis rate of depression is not low. Furthermore, long-term frequent use of antidepressants may bring both psychological and economic burdens to patients.
    Out of the solicitude for depression patients and the thought of solving existing problems, we designed engineered bacteria that colonize the human intestine for long-term drug secretion. We selected the intestinal probiotic Bifidobacterium longum as our chassis bacteria and a Production Module was constructed to synthesize and secrete SAMe, which can alleviate symptoms of depression more effectively.
    Additionally, we engineered the Oscillator Module to periodically regulate the production of SAMe and the serum drug concentration, and optimized the Oscillator Module by our Directed Evolution Module.
    To ensure biosafety, Safety Switch was imported into the bacteria. We plan to provide a novel treatment for depression using synthetic biology techniques and we hope to improve the lives of depression patients.
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4. Contribution

    We added new information learned from the literature and the experimental qualities to the previous parts (BBa_K143057, BBa_K322921, and BBa_K1054002). Furthermore, we have documented an optimized method to transfer plasmids into Bacillus subtilis with the help of PI Xie's lab. Meanwhile, we built two models to validate the feasibility of our overall design and offered a method to depict the concentration change of chemical substances, which may be useful for future iGEMers. In addition, we manufactured a portable dual port filter for bacteria activation in wet lab and designed a device to simulate the flow and intestinal peristalsis in the intestinal tract, to better instruct the final form of the drug's external package.
    All of these may be helpful and useful for future teams, and we hope our work will make contributions to the iGEM community.
    Contribution Part Number: BBa_K143057, BBa_K322921, and BBa_K1054002.
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Silver

5. Engineering Success:

    We have accomplished Design-Build-Test-Learn (DBTL) cycles in Production Module, Oscillator Module, Directed Evolution Module, Safety Switch Module and Hardware.
    In Production Module, we used DBTL cycle to improve the enzymatic activity of SAMe synthetase opSam2 (BBa_K4144011) and to improve membrane localization of SAMe transporter opPet8p ( BBa_K4144004) by designing a new part (BBa_4144010) considering the structural disruption caused by sfGFP.
    In the Oscillator Module, we used the parts of Repressilator (BBa_K3482025) to test their function. And we failed many times but finally made it to observe green fluorescence and explored the suitable way of testing the oscillation.
    In the Directed Evolution Module, to develop a lactose-tolerant LacI protein is our goal. After several rounds of selection, we have gained a colony with expected LacI in a certain way.
    In the Safety Switch Module, we struggled to construct double switches using Holin and EGFP. We met great difficulties during the process, but we successfully got positive results in a part of test experiments in the end.
    In hardware, we improved efficiency of Portable Dual Port Filter based on results of previous experiments. We have characterized several new basic parts in engineering this year: BBa_4144004, BBa_K4144011, and BBa_K4144012.

6. Collaboration:

    This year, we tried our best to establish a tight bond between the external world and ourselves.
    We have communicated with high school teams to help solve their problems in the project and organize promotion to extend the influence of synthetic biology. We have collaborated with NJMU-iGEM in an all-round way, discussing design, goals, mechanisms and commercial strategies, which effectively improve both projects. We actively participated in online meetings, ICII, CCiC and other activities, all of which were attended by iGEM teams all around China. In those communications, we built bridges between other teams and got many inspirations. And collaboration with enterprises such as Bluepha and MGI availed us of exploring the commercial possibility of our project.
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7. Human Practices:

    In the past year, we have accomplished a lot of human practices to make the public better know about depression, synthetic biology and iGEM, and committed to doing our best to alleviate the suffering of patients with depression. It was the mental health lecture led by us and NJMU and an online academy that helped university students deepen their understanding of autism and depression. Thereafter, in a class meeting for 2021 students and a welcome meeting for 2022 freshmen of the College of Life Science in WHU, we aroused their interest and curiosity in iGEM, and opened a new door toward biology for them. In the Elite Program, the three-day journey made high school students enthusiastic about synthetic biology. In addition, we have operated our official WeChat account and released questionnaires on it constantly to take advantage of the influence of an open internet platform to deepen the public's understanding of depression.
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8. Proposed Implementation:

    
    Our project aims to build a kind of engineering bacteria as an antidepressant drug. To put our product into the real world, we have made efforts in not only the design but also the real word plan.
    In terms of design, we built the Oscillator Module to keep the drug concentration stable in the human gut and blood. And we built the Safety Switch Module to make our product safe for patients and the environment. In terms of real-world plans, we first interviewed some experts and pharmaceutical companies to get advice on our project. After we built a framework of our business plan, we made a questionnaire to survey which product form of antidepressant drug the patients prefer. Considering the effect, profit, the feeling of patients, and society's reflection, we finally chose milk tea powder comprising freeze-dried engineered bacteria as the form of our product.
    And we made a series of models based on it to create a thorough business plan and put our product into the real world. What we think our project stands out is that we put our customers, depression patients, in the first place.
    We try to give patients a brand-new feeling about drug taking. We believe our product could not only make profits but also improve the real world.
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Gold

9. Integrated Human Practices:

    During the whole year of practice, interaction with professors, enterprises and the organization of patients benefited us a lot.
    In the preparation stage of the project, we determined the direction of our project by conducting a wide range of questionnaires to understand the hot issues of public concern.
    During the process, the communication with DO&GO made us truly feel the pain of patients with depression, and make targeted modifications to the project to better solve the existing problems.
    At the same time, when facing the difficulties encountered in the experiments, we consulted experts in the field of medicine and pharmacy through online and offline channels, and kept improving our project.
    The communication with enterprises also gave us a clearer understanding of the form and positioning of our future product.
    All in all, a series of social practice activities, out of the laboratory, made our project more scientific and logical.
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10. Improvement of an Existing Part:

    In order to maintain the stable period of our oscillator “Repressilator”, we designed the Directed Evolution Module to develop LacI repressor, making it only responsible to high-level lactose that hardly exists in normal intestine environment. Using site-saturation mutagenesis, we created a mutant library and drive the ideal variant through series of selective culture of the engineered bacteria. Our developed LacI repressor showed no expression under low lactose condition, and the leakage problem of the lac promoter is also greatly improved after this mutation.
    Old Part Number: BBa_C0012.
    Improved Part Number: BBa_K4144041.
    Detailed experimental design and results can be found on Results and BBa_K4144041.

11. Project Modeling:

    Our inspiring modeling work has been closely related to the wet lab experimental work. The models helped our team conduct wet experiments more wisely and get a deeper understanding of some quantitative characteristics as well as some attributes in our whole system.
    Firstly, the simbiology-based model successfully validated our overall design ideas, enabling the experimental group to proceed in a clear direction. Then, our oscillator model explained the oscillation module specifically. According to the final results, we learned the effect of protein degradation rate and colony size on the oscillation behavior, which provided the experimental group with some suggestions on the oscillator modification.
    Secondly, after having designed the oscillation module, we used a molecular concentration prediction model to simulate the change of drug concentration in the blood. Moreover, both single-dosing and multiple-dosing scenarios were discussed in detail to analogize the situation of a person taking medicines in daily life. According to the final results, we adjust various parameters of the model (e.g. the rate of drug secretion) to guide the experiments of the wet lab.
    Finally, we use visualization methods to depict our model results, which allows judges to input parameters and obtain simulation information more obviously.
    In conclusion, our models match with wet experiments perfectly and are more close to daily life. View More

12. Proof of Concept:

    Through a year's preparation and lab work, we've achieved basic proof of concept via several fundamental experiments, models and hardware.
    To develop a novel depression therapy, we planned to engineer one bacterial strain of Bifidobacterium longum (B. longum) with natural anti-depression capacity to generate natural antidepressant S-adenosyl methionine (SAMe).
    We chose Bacillus subtilis (B. subtilis) as the experimental gram-positive bacterial model to engineer. We have engineered such strain to synthesize SAMe in high efficiency (BBa_K4144008 and BBa_K4144011), and to be able to secrete SAMe (BBa_K4144004, BBa_K4144006 and BBa_K4144007).
    The production of SAMe can be regulated by the oscillator (BBa_K3482025) module, which will ensure that drug plasma concentration remains appropriate meanwhile reducing side effects and changes in a periodical way.
    To make our oscillator not disrupted by lactose in human intestine, we designed a directed evolution pipeline (BBa_K4144041) to increase the tolerance of LacI for lactose. Meanwhile, we added parallel safety switches to ensure the biosafety (BBa_K4144081 and BBa_K4144082).
    In Model Group, we built the entire system with SimBiology, simulating our design concept. Moreover, we modeled the oscillator module and our second model—Molecular concentration prediction model provided the experimental group with suggestions on how to improve the stability and period of the oscillator as well as how to improve the secretion rate and satisfy the minimum concentration limits.
    In hardware, we have built the portable dual port filter to improve wetlab efficiency and the enteral drug simulation device to characterize the drug delivery system. View More

13. Partnership:

    Throughout all phases of the competition, we and NJMU-iGEM have kept in close touch, reaching out to each other whenever one ran into any problem, with a frequency of at least once a month. Depending on effective videotelephony such as Tencent Meeting, we were able to hold most of our events and communications online, including Wet Lab, Modeling, Safe and Business. Together, we planned and completed the online platform related to gut microbiota. There were also a series of popular science and education activities jointly organized to make our cooperation even closer. View More

14. Education and Communication:

    We have been committed to reaching different groups and sowing the seeds of synthetic biology as much as we can, in an attempt to let the knowledge and spirits of life sciences take root in as many communities as possible. Our way of education is not only organizing online and offline science communication activities, but also one-on-one interviews. We also extended the educational content from theory to practice. We invited high school students into the lab and taught them about molecular biology. PPT, experimental materials and arrangement of the courses were completed by our team members independently.
    We cherish all the opportunities to communicate with others, through which we continue our missions to popularize synthetic biology and iGEM, and gain valuable suggestions for the development and improvement of our project at the same time. View More