Difference between revisions of "Team:BIT-China/Project/Description"

Description

COOPERATION WITH OTHER UNIVERSITIES

At the latter phases of our project, we organized Beijing University, Lanzhou University and Jilin University etcetera to make a big chat about what we had done so far and held three scientific speeches to introduce the development and the common use of sweeteners in our daily life, which contributed to the increase of popularity of iGEM as well as Synthetic Biology.Ultimately, we collected the critical advice from the audiences in time and accept one of them, which recommended us to set saccharose as the standard, after that running the test would be more reasonable.

SWEETNESS AND WE

Sweetness, a word that is associated with happiness and satisfaction. For most higher animals, it is innate that they prefer the sweetness. Human is not an exception because people are always addicted to the sugar. When we have sugar, our brains will release serotonin, which can make us feel delightful.

WELL WHY?

However, according to the data from the World Health Organization (WHO), having excessive sugar is more harmful than smoking. Having excessive sugar can not only cause obesity, obviously, but also can trigger diseases, such as diabetes and gout.

With the development of technology, artificial sweeteners are becoming better choices. The production technology of artificial sweeteners is becoming more mature. Meanwhile ,as a food additive, artificial sweeteners are also more widely used in the field of food production. But the potential harm of artificial sweeteners to humans is still a controversial issue.

Therefore, it is imperative to detect the ideal sweetener to tackle the problems we mentioned above as well as satisfy our gustation.

THEN WHAT?

With the development of synthetic biology, the types and production of natural products of microbial synthesis are increasing. Does the natural product produced by the microorganism contain some undiscovered sweeteners? Thus we hope to design a system which can identify sweeteners and be able to distinguish the sweetness of these substances by corresponding signal expression.

First and foremost,we must understand the mechanism that people can feel sweetness: the human sweet G protein-coupled receptor T1R2-T1R3. It is a pair of extracellular proteins with homodimer，which has six structural domains. Different sweet substances combine with different regions of T1R2-T1R3，then triggering intracellular G protein coupled pathway and leading to downstream signal expression. Finally, it can lead to a "sweet" feeling.

At the same time, we chose yeast cells as host. We hope to replace its original G protein-coupled receptor Ste2 , which is related to yeast’s mating with the T1R2-T1R3. And some side effects genes are knocked out by homologous recombination technology. After building a complete system, we hope to judge whether the material has sweetness according to whether the signal can express. If there is a response, we hope to judge the sweetness of the substance by the strength of the signal.

BUT HOW?

Our experimental part is divided into three parts:

Host Reconstruction: host reconstruction group uses homologous recombination methods ,using Trp, His, and Ura as screening marker fragments with homologous arms to knock out Ste2, Sst2, and Far1 genes in yeast.Except Ste2 , Sst2 gene can inhibit the signal transduction of Gpa1 protein.Far1 gene avoids interference signal for sweet yeast yeast normal physiological function after transformation.

Receptor Expression: the receptor expression group uses OE, PCR, and other methods to achieve the synthesis of T1R2-T1R3 G protein coupled receptors. The detection team constructed the pFUS and the red fluorescent protein line to detect the sweetness and sweetness functions through the expression of the fluorescent signal.

Detection of Circuit:in combination with our project, our mathematical modeling also establishes three sets of models that provide guidance for our experiments and achieve the desired functional simulation.