Essay On L. Lactis

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Bio Article Summary
Currently, there is a lot of research exploring the development of food-grade microorganisms to control the production of desirable enzymes and proteins. The point of this article is the try to find an inducible expression system, similar to the one already discovered in E. coli. In this article, L. lactis is explored as a possible inducible expression system. L. latis is a lactic acid used in the dairy industry and other food fermentations. It is studied in this experience because it has the potential to be a safe production host for the development of food-grade microorganisms. Safe genetic tools (acceptable for food production) have already been developed to aid in the potential production of food-grade
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Nisin is an antimicrobial peptide that is often used in the food industry as a natural preservative. The nisA gene is a major structural gene of the nisin gene cluster and is auto-regulated. This means that a modified nisin peptide can induce transcription of the nisA gene through the means of a signal transduction by way of a regulatory system involving histidine kinase (NisK) and response regulator (NiR), also known as a positive feedback loop. If nisin is present, the nisA gene is turn on to produce more nisin. In this experiment, a series of vectors and strains were produced through transcriptional and translational fusions to the nisA region. Transcriptional fusion involves the placement of the gene being enhance downstream or behind of the promotor. Translational fusion involves the slicing of the gene being enhanced into another gene. Both fusion methods result in a protein. The nisA promotor was analyzed first through the construction and the use of nisA transcriptional fusion plasmids. Plasmid DNA from L. lactis protoplasts was isolated and amplified through PCR. DNA fragments containing the nisA promotor region were then isolated and cloned in pNZ273 to create pNZ8008. pNZ273 is a transcriptional vector based on the promotorless E. coli gusA gene, and was able to create the expression vector (pNZ8008) used to explore the nisin-induced expression of the nisA promotor. The
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