THEY ARE SHORT ANSWERS. SO DONT HAVE TO WRITE 2-3 PARAGRPHS FOR EACH. JUST EXPLA
ID: 267016 • Letter: T
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THEY ARE SHORT ANSWERS. SO DONT HAVE TO WRITE 2-3 PARAGRPHS FOR EACH. JUST EXPLAIN EACH BRIEFLY. THANKS?
PLEASE LABEL EACH QUESTIONS WITH THEIR EQUIVALENT NUMBERS
14. A specific target DNA fragment to be integrated into the chromosomal DNA of the host organism can include (1) only the target gene sequence or (2) the entire plasmid, including the target sequence. Explain how each of these results might occur. What are the advantages or disadvantages of the plasmid vector becoming incorporated into the host chromosomal DNA? 15. Suggest a number of different strategies to limit the extent of metabolic load on E. coli cells that are designed to overproduce a recombinant protein. 16. During the course of integrating a target gene into the chromosomal DNA of the host bacterium, a marker gene may also be inserted into the chromosomal DNA. What strategy could be used to excise only the marker gene? 17. How do biofilms limit the production of recombinant proteins? How might this limitation be overcome? 18. How can E. coli host cells be engineered so that complex proteins with a large number of disulfide bonds are properly folded and therefore produced in an active form rather than as part of an inclusion body?Explanation / Answer
The specific target DNA fragment or gene sequence or plasmid can be integrated into the chromosomal DNA of the host organism. This has the major advantage that continued propagation on the incorporated gene sequence or plasmid is assured through many generations. The needed gene function thus can be obtained for many generations.
Answer 15.
Recombinant E.coli cells are produced with the aim to obtain high production of desired protein/component. The overproduction of recombinant proteins by the cells put excessive metabolic load on the cells. If production is desired for long duration, the metabolic load must be reduced. The strategy to reduce metabolic load include tuning of transcription. Tunable expression systems allow adjusting the recombinant protein expression using process technological means. This enables to exploit the cell’s metabolic capacities to a maximum and for long duration. The strategies for expression tuning involve - knockout of genes for inducer.-the knockout of transport genes breaks the positive feedback of the inducer on the production; and modification by addition of vector harbouring lysozyme that converts the unstable response of the cell to the stable response.
Answer 16.
Selectable marker genes are used for the chromosomal insertion of heterologous genes to create new recombinant strains of bacteria. The insertion a marker gene may alter the expression of adjacent chromosomal genes. Hence, excising the selectable marker gene is of significant advantage. One of the strategies includes Xer dimer resolution system. The other strategy involves use of site-specific recombinases, under the control of inducible promoters, to excise the marker genes.
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