Difference between revisions of "Team:Nankai/Practices"

Human Practice:

1. What is iShare?

During the summer, we ran into many problems when we were working on our experiments. The lack of materials for instance, is one major difficulty that occurred to us. To continue our project, we had to acquire those materials from other laboratories, which involved us into intellectual property issues..

Thanks to the current system of material transformation, we managed to put all the things we needed together. Most of the laboratories would share their resources with us if we sign the material transfer agreement with them. However a small community as Nankai University is, it still took us a long time to find the right materials we needed. We could imagine how difficult if an iGEM team seeks for information about certain materials among the hundreds of previous teams.

As far as we have concerned, iGEM has already established a functional platform for all the participators to share Bio-bricks that have been submitted since the birth of the event, which is absolutely an excellent work for resources sharing. But there is no information about other materials related to the Bio-bricks, such as bacteria strains, antibodies, enzymes and so on. So our suggestion is that iGEM design a special webpage or a section on wiki for iGEM teams to list the materials they use in their experiments. In addition, iGEM teams could label the materials which they are willing to share. And teams who are interested in those materials could contact the owner for more information or a way to acquire the materials. In this way, future teams could have more resources for similar work and may come up with more improvements, while all iGEM need to do is to provide an information platform like “iShare”.

A mature system of all-round resources sharing could definitely make iGEM a better community. Before it could be accomplished, let’s make the first step by setting up an information sharing platform to promote material sharing. Team Nankai has already designed a model for i-Share. See more information on our wiki, and join us to make iShare better and better!

2. iShare Surveyh4>

Bacillusamyloliquefaciens LL3, isolated from fermented food, is a glutamate-independent strain, which can produce 3-4 g/L γ-PGA with sucrose as its carbon source and ammonium sulfate as its nitrogen source. The B. amyloliquefaciens LL3 strain was deposited in the China Center for Type Culture Collection (CCTCC) with accession number CCTCC M 208109 and its whole genome has been sequenced in 2011. In this study, we aimed to improve the γ-PGA production based on the B. amyloliquefaciens NK-1 strain (a derivative of LL3 strain with its endogenous plasmid and upp gene deleted).

4. What did we do?

In order to improve γ-PGA production, we employed two strategies to fine-tune the synthetic pathways and balance the metabolism in the glutamate-independent B. amyloliquefaciens NK-1 strain. Firstly, we constructed a metabolic toggle switch in the NK-1 strain to inhibit the expression of ODHC (2-oxoglutarate dehydrogenase complex) by adding IPTG in the stationary stage and distribute the metabolic flux more frequently to be used for γ-PGA precursor-glutamate synthesis. As scientists had found that the activity of ODHC was rather low when glutamate was highly produced in a Corynebacterium glutamicum strain. Second, to balance the increase of endogenous glutamate production, we optimized the expression level of pgsBCA genes (responsible for γ-PGA synthesis) by replacing its native promoter to seven different strength of promoters. Through these two strategies, we aimed to obtain a γ-PGA production improved mutant strain.Click for more detail.

5. How do we use γ-PGA?

We prepared SOD loaded γ-PGA hydrogel for wound healing. SOD was loaded into hydrogels to scavenge the superoxide anion and γ-PGA was modified with taurine to load more SOD. γ-PGA hydrogel had high water absorption properties delivering the important moist environment. SOD released from the hydrogel maintained high enzyme activity and SOD-γ-PGA hydrogel could scavenge the superoxide anion effectively. In vivo results showed that SOD-γ-PGA hydrogel could promote collagen deposition, epithelialization, and accelerate the healing of moderately exuding wounds. Therefore, SOD-γ-PGA hydrogel would be a good candidate for wound healing applications. Learn more on Pudding Health Kit.