NoteBook

The XMU-China 2025 team officially kicked off recruitment! Over a hundred students from different schools signed up to join us, diving into training on project design and exploring the wonders of synthetic biology together. A vibrant and energetic team is gradually taking shape!

As the new year fireworks lit up the sky, we finalized the formation of our team. Members got to know one another and made heartfelt wishes for the success of our project this year!

Our very first offline brainstorming session! Although it was the first time many of us met in person, everyone quickly grew comfortable.

We shared our project dreams over dinner, and later, the leader and advisors led us in singing our hearts out at KTV. A night to remember!

Gathering again at Siming campus, Advisor Liuqin Wu guided us on Human Practices— covering how to conduct interviews, design questionnaires, and prepare as professional investigators. Everyone walked away with valuable skills.

Being a team from a coastal city, XMU-China has always had a bond with the ocean. This year, we turned our eyes toward fish — a staple on our dining tables — which often suffers from spoilage. We proposed developing an eco-friendly preservative. Inspired by the sea itself, we started designing a project to extract a high-quality preservative from shrimp and crab shells: "sourced from aquatic products, used for aquatic products."

Students from Siming and Xiang'an campuses gathered in the chemistry building for lab training! Guided by our leader and advisors, we systematically learned the basics of molecular cloning. One teammate exclaimed, "I finally became a synthetic biology master — I can't wait to start my own experiments!"

A teammate Ruichen Shen designed a creative gene circuit nicknamed the "Pop Quiz Suicide Switch". While worrying about their English test, the team was also training hard to prepare for the upcoming Grand Jamboree.

XMU-China 2024 received an official commendation from Xiamen University!

Today is our first pre experiment after the experimental training, measuring the growth curve of the strain. Unfortunately, the first experiment did not go as smoothly as we expected. Our culture was contaminated with other bacteria and had an unusual odor.

This is our second attempt, and the growth of the strain is relatively normal, but the parallelism of the experiment is not very good, and we still have room for improvement.

Teammate Yunxin Wang wrote that, in the morning, four of us from Xiang'an filmed our team introduction video by Lake Furong. After some debate over filming locations, we spotted black swans gliding across the water and decided to shoot with them — the final footage turned out beautifully!

Can you believe it — three teammates' birthdays all in the same week? After wrapping up our project discussions at Xiang'an, we took a group photo and celebrated the birthdays of Jiayue Qu, Jialin Chen, and Yanlinxin Guo with three custom cakes. What an atmosphere! The birthday stars said: "We're so happy to be part of the XMU-China family, may we always stay the best of friends!"

Today, we tested the bactericidal effects of chitooligosaccharides with different degrees of polymerization on E. coli. The experiment required us to monitor bacterial growth continuously for 24 hours, and students from the Siming campus took shifts to complete the task.

Teammate Jiaxuan Peng wrote that: First time sleeping in the laboratory! The final exams are approaching and we are all very anxious, but now the gene circuit I designed urgently needs data to prove its feasibility, so I am staying up late in the laboratory monitoring the growth status of the strains. Very exhausted, but finally obtained some valuable data!

Happily, the toxicity of the chitooligosaccharides we tested was similar to what has been reported in the literature, but we need to conduct more experiments for further verification.

We attempted to verify the toxicity of chitooligosaccharides using LB agar plates containing the oligosaccharides, but the results were not ideal, with significant variations between different parallel groups.

Students from the Xiang'an campus re-evaluated the bactericidal effect of chitooligosaccharides using the spotting method on LB plates. This has provided an experimental foundation for our use of self-produced chitooligosaccharides in sterilization.

We had been struggling with the low solubility of chitosan, which made it difficult to prepare high-concentration stock solutions for degradation experiments. Today, we attempted to pretreat chitosan with hydrogen peroxide and successfully dissolved it!

After weeks of stubbornly refusing to assemble, our secreted-peptide LMT mutant finally ligated, transformed, and sequenced perfectly. Cue the silent lab-wide happy dance (so we wouldn't wake the E. coli).

Based on our preliminary research, we selected six enzymes for degrading chitosan. Today, we successfully expressed the first one!

To prepare for preservative testing, we made countless PCA agar plates — filling every corner of the biosafety cabinet and cramming the fridge. Though exhausting, it felt so rewarding.

Today we used fish for our preservative experiments. The lab smelled faintly of the sea, but the parallelism of our results improved significantly. It finally feels like our chitooligosaccharides is shining!

Today, we tested the degradation effect of the CsnMY002 enzyme, but the results were unsatisfactory. We need to try more enzymes.

We warmly welcomed high school iGEMers from MammothEdu-South, exchanging project ideas and sparking shared excitement for synthetic biology.

Our team member Yunxin Wang wrote: Since there were not enough beakers in the Xiang'an campus laboratory to soak the fish, I improvised by soaking it directly in a sterile bag. With this adjustment, our preservation experiment achieved full aseptic operation throughout the process. Hopefully, the results will be more accurate now.

The bacterial strains in the lab are having a competition to see which one is greener. We are screening for suitable secretion peptide mutants based on their ability to secrete green fluorescent protein.

After a period of discussion and design, we decided to start attempting random mutagenesis on SaCsn46A. However, we did not obtain the correct bands, so we need to adjust the random mutagenesis conditions.

Our team member Cairui Chen wrote: Doing TLC experiments is indeed a skilled task. Using potassium permanganate method from organic laboratory for experiments will result in too large sample dot size of the product. We need to find a suitable method specifically for chitooligosaccharides.

We celebrated teammate Keshuo Zheng's birthday!

The HPLC column pressure has been consistently high over the past two days. Although everyone suspects macromolecules might be affecting the column, no clear improvement was observed regardless of the mobile phase used. With the help of her senior, Meihan tried various methods, but the pressure remained stubbornly high. Eventually, even her senior concluded that the column might simply be broken. Meihan was upset because this could delay the entire experiment. As a last resort, she decided to flush the column with the mobile phase once more. In the early hours of the morning, when no one held much hope, the pressure finally began to drop!!! Meihan loaded her samples overnight, hoping for good results the next day.

We attempted to use the aniline blue plate method to identify different chitosan enzymatic hydrolysis products, but found little difference in the diffusion of chitooligosaccharides with different degrees of polymerization. We need to find a new identification method.

After days of mutagenesis trials, using freshly prepared manganese chloride finally yielded correct bands — a breakthrough, though mutation rates remain to be determined.

Today, we tried using the DNS method for the quantitative detection of chitooligosaccharides. The solution turned a beautiful reddish-brown after the reaction—we succeeded!

We finally found the optimal developing solvent formulation for the TLC experiment. Today, we used it to identify chitooligosaccharides with different degrees of polymerization, and the results met our expectations!

After a period of exploration, we have finally defined the experimental conditions for producing chitosanase and degrading chitosan. We can now start testing the degradation capabilities of different enzymes!

Our teammate Nanqin Lin wrote We'd been stuck for days: co-electroporating our knockout fragment with the editing plasmid just wouldn't take.

Our instructor Junhong suggested a two-step rescue—first get both plasmids in, then add the fragment later.

I blurted out, "But I've never pulled off a double-antibiotic transformation…"

He looked me dead in the eye and said, "This time you will."

Next morning—boom—double-resistant colonies on the plate.

Sometimes all it takes is a senior's faith and a fresh set of cuvettes.

Do you remember the "Pop Quiz Suicide Switch"? The creator of our earlier gene circuit unveiled an upgraded version featuring: the "Wish Fulfilled" promoter, "Clear Mind" RBS, "Successful Experiment" factor, and "Never-ending" terminator. With such a circuit, success feels guaranteed!

Our lab member Ruichen Shen wrote: Picked 88 mutants of CsnCA for colony PCR. Although very few were successful, we still obtained over ten valuable mutants.

Our team member Cairui Chen wrote: Sometimes certain bacterial strains can be unpredictable in experiments. They perform well in the first screening but fail in the second. Yes, we're looking at you, LMT variant M13L.

For the first time since summer started, one teammate finished experiments before 10 pm! Of course, we celebrated with delicious food afterwards.

Our team member Yunxin Wang wrote: Today we successfully constructed the plasmid containing the SaCsn46A mutants sequence. Thanks to Ruichen Shen for assisting with the transformation! We had several failed transformation attempts before, but Ruichen Shen succeeded effortlessly. We truly appreciate his skilled hands in transformation!

Our team member Cairui Chen wrote: This is our first time conducting a preservation experiment on fruit! The chilled blueberries were delicious, but not very suitable for the experiment, as the properties varied too much between individual blueberries. We will select other fruits.

And our lab member Ruichen Shen wrote: The lab ran out of TAE buffer, and no one could run gels. I tried making the stock solution myself, and it worked exceptionally well.

Off to the China Conference on iGEM Competition we went! Swapped stickers, pins, and stories with teams from ZZU, XJTLU, ZJU, and more. Our poster has received praise and likes. Fellow iGEMers loved our seafood-preservation angle and tossed us fresh ideas We soaked up keynote talks from professors and biotech CEOs, then raced back to the hotel to scribble down every last insight. Three days, a suitcase full of new friends, and brains bursting with inspiration—mission accomplished!

With the help of students from the Xiang'an campus, our progress has accelerated significantly. The enzymes SaCsn46A and CsnCA tested today showed promising degradation effects.

Our team member Keshuo Zheng wrote: Today was a long day! One member of our team simultaneously conducted molecular cloning experiments and monitored cell growth status. Even though things got a bit hectic, we still achieved successful outcomes in the end!

Today, we tried using the Hammer Bacterial Lysate to lyse the bacterial strains. It was expensive, and we had high hopes for it, but its performance was disappointing. We still need to use the ultrasonic instrument.

The typhoon is about to hit, and Jiaxuan and Meihan, who stayed up late working on their experiment, decided to bunk overnight in the break room—494, zzzzz...

Luckily, their lab buddies left some snacks behind—munch, munch, munch... zzz

Who's to say this isn't a modern twist on "Willow-lined shore, dawn breeze, fading moon"?

("Willows"—by the shore, howling typhoon, not a moon in sight...)

Today's experimental results were somewhat disheartening. We found that constructing enzyme mutants in the pSB1C3 vector rarely produced the correct plasmids, indicating we might need to change the vector.

The pET-28a(+) vector came to our rescue! Today, several McChoA enzyme mutants we constructed showed a high rate of correct bands.

Team member Keshuo Zheng wrote: Today we wrapped up the LMT improvement experiments. We've successfully validated the mutation effect of C14A and obtained promising data!

After several days of effort, we finally obtained over 100 bacterial strains containing SaCsn46A enzyme mutants. We have decided to start the "Great Enzyme Screening" experiment soon.

Today was a big day for our XMU-China iGEM team! We held a science outreach event at the Xiamen Science and Technology Museum, themed "sourced from aquatic products, used for aquatic products" Our goal was twofold: to spark curiosity in kids and teens about the hidden value in shrimp and crab shells, teaching them to appreciate these marine resources and understand the importance of seafood freshness and safety. On the other hand, we were thrilled to share our team's innovative solution for recycling crustacean waste, offering the public a glimpse into the amazing potential of synthetic biology to make a difference.

Our "Great Enzyme Screening" experiment started today. We carried out screening of 104 variants of the randomly mutated chitosanase. The workload was tremendous, yet everyone worked together seamlessly, passing the tasks along like a relay. Step by step, we pushed through — and finally, we were rewarded with solid results.

Our lab member Ruichen Shen wrote: The new semester has begun! We got a new ice box and drew little caricatures of our team members on it.

Today, while preparing to purify proteins, Meihan discovered that the AKTA protein purification system she usually uses was out of order. As a result, she had to seek help from others. Fortunately, Advisor Yanhao Chen provided extensive assistance. He guided Meihan in using a new protein purification system and successfully helped her purify the proteins. Grateful for such a supportive team!

Our team member Nanqin Lin, who is exploring the construction of a suicide switch, wrote: The issue that had been troubling us for almost two weeks—where the Donor for genomic insertion consistently showed 2000 bp in PCR—has finally been resolved! It turned out that the first and fourth segments were preferentially connecting. We succeeded by performing the connections in batches!

Our teammate Cairui Chen wrote: Today, under the guidance of our advisor Ziyan Han, I successfully learned how to use our lab's new AKTA system to purify the protein SaCsn46A mutants. It was incredibly rewarding to see the solution turn blue during the Bradford assay test—a clear sign of successful purification!

Our team member Yunxin Wang wrote: Today, we finalized the use of CFU/g as the metric to evaluate the preservation effect in our experiment. To prepare for this, we made a large number of PCA plates. My skills in pouring and arranging plates have now been fully mastered!

We've occupied almost all the instruments in the lab that can heat liquids, because today we set up many different temperatures to test enzyme stability across various conditions.

Our team member Cairui Chen wrote: Testing enzyme activity under different pH conditions is not easy. We've used up a lot of pH test strips just to calibrate the pH correctly.

Our team member Yunxin Wang wrote: Today, we attempted to use chitosan degradation products for fish preservation for the first time. While buying the fish, we encountered an incredibly cute puppy at the store. From now on, I'll always buy fish from this supermarket!

Our teammate Jiaxuan Peng wrote: We ran multiple enzyme kinetics experiments today, but all failed. When chitosan was not treated with hydrogen peroxide, the reducing sugar background was very low, making it impossible to detect any enzymatic activity. After treating chitosan with hydrogen peroxide, the reducing sugar background showed a direct linear relationship with substrate concentration, yet we still couldn't observe any enzyme effect and have to give up this experiment. What a disheartening day!

In Xiang'an Campus, team member Jiayue Qu wrote: While conducting experiments to test the effectiveness of secreted proteins for the POC section, we obtained exceptionally clean and clear protein gel results! The outcomes are closely aligned with our expectations — truly exciting!

We prepared a large amount of secreted chitosanase and used it to degrade chitosan. With these preparations in hand, we are now ready to launch the preservative experiment to verify the preservation effect of our mutants.

A strange smell has appeared in the lab? Where is it coming from? Oh no, it's from the bacterial contamination of the chitosan degradation products in the supernatant from our POC experiment. We need to repeat the experiment.

We used the protein obtained from yesterday's experiment to degrade chitosan. The TLC and HPLC results confirmed that the protein has good degradation activity!

Our team member Nanqin Lin, who is exploring the construction of a suicide switch, wrote: After changing the promoter, we finally detected the correct band for the genomically inserted bacteria! I'm genuinely thrilled! Although subsequent sequencing revealed that the ccdB segment was still missing...

Our team member Cairui Chen wrote: Today, Ruichen Shen suggested that we adjust the dilution factor for tomorrow's experiment on the preservation of chitosan degradation products. Oh, but he forgot that the last plating was already done yesterday—by tomorrow we'll have all the data. Poor guy, his brain must be fried from staying up late writing the results section last night.

Our lab member Ruichen Shen wrote: Completed the first colony count test for the preservation experiment using degradation products. The preservation effect of the degradation products is remarkably good!

Today, Meihan pulled an all-nighter for LCA calculation. During a break, she went to witness the breaking dawn: the first light piercing through the sky, the early mist rising, kites soaring high, and winds sweeping across the horizon. She reminisced about verses of journeys, turbulence, and perseverance, and wished for a smooth wiki freeze.

Wiki Freeze!