Optimization of a glucose-responsive genetic circuit

Abstract

The human microbiota plays a fundamental role in maintaining the health of its host, with many pathologies associated with the imbalances of this microbiota. One of the types of microorganisms existing in the human intestinal microbiota are probiotics, which have beneficial activity for our organism, and their existence is very important. In recent years, research on synthetic biology aimed at creating more efficient probiotics, the so-called therapeutic probiotics has been gaining strength. This project aims to optimize a robust, orthogonal and modular genetic circuit responsive to glucose, in which the presence of glucose in the body generates an identifiable response. This circuit will be characterized in Bacillus subtilis, a probiotic chassis with great potential for use in synthetic biology. This project is a continuation of a previous CI project developed by - RIBEIRO, NV- (Process 20-18 / 04703-0). The student completed the construction of a simpler system regulated by an sRNA. Then he built a more complex system, with different levels of regulation. However, a failure in the construction of some promoters, identified during the sequencing, did not allow the regulatory circuit to function properly. The objective of this project is to correct the faults in this circuit in order to make it more efficient by means of complex and connected parts that reduce leaks and allow a high level of expression when activated. With this, it is intended to develop tools applicable to these two chassis, which can be used in future projects and serve to advance research in therapeutic probiotics. This research, for example, may be the precursor of a biosensor for glucose with diverse applications such as the creation of sensor kits, the presence of glucose in samples and even the development of "designer probiotics", that is, probiotics genetically engineered with the intention to deliver therapeutic molecules to body tissues, in this case probiotics capable of producing insulin in the presence of glucose, as a form of complementary treatment for type 1 diabetes.