How do plasmids differ from bacterial chromosomes

Plasmids contain genes that impart antibiotic resistance. Up to eight genes for resisting eight different antibiotics may be found on a single plasmid. Genes that encode a series of bacteriocins are also found on plasmids. Bacteriocins are bacterial proteins capable of destroying other bacteria.

Still other plasmids increase the pathogenicity of their host bacteria because the plasmid contains genes for toxin synthesis. Transposable elements. Transposable elements, also known as transposons , are segments of DNA that move about within the chromosome and establish new genetic sequences. They generally carry only a small number of genes, notably some associated with antibiotic resistance. Plasmids may be passed between different bacterial cells.

Small pieces of DNA, such as human DNA, can be attached to appropriate elements, circularized, and then introduced into bacteria, where they are propagated--or in other words, copied--along with the host bacterial chromosome. Read more about how to add foreign DNA to bacteria. Add to collection. Go to full glossary Add 0 items to collection. Download 0 items. Twitter Pinterest Facebook Instagram.

Email Us. See our newsletters here. We have constructed all the plasmids necessary to undertake such multi-step ACE strategies at each of the loci studied here Table 1. In our proof-of-principle experiment over 40 kb of lambda DNA was inserted into the chromosome of C.

After each successful transformation of the lambda constructs, double-crossover clones were obtained just as easily as in the earlier experiments using the empty vectors. Apparently, inserts of this size substantially decrease transformation frequency to a level that reduces the practicality of the procedure.

This observation suggests that the size of inserts used in multistep strategies, at least in C. Inserts L28 and L12 appear to be larger than the optimum.

Funding for open access charge: The University of Nottingham. Conflict of interest statement. The University of Nottingham has filed a patent application encompassing some of the work described in this article. The patent application names J. We thank Drs Alexandra Faulds-Pain and Sarah Kuehne for valuable criticism and suggestions during preparation of the manuscript.

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Search Menu. Article Navigation. Close mobile search navigation Article Navigation. Volume Article Contents Abstract. Integration of DNA into bacterial chromosomes from plasmids without a counter-selection marker. Heap , John T. Oxford Academic.

Muhammad Ehsaan. Clare M. Yen-Kuan Ng. Stephen T. Klaus Winzer. Nigel P. Revision received:. Cite Cite John T. Select Format Select format.

Permissions Icon Permissions. Abstract Most bacteria can only be transformed with circular plasmids, so robust DNA integration methods for these rely upon selection of single-crossover clones followed by counter-selection of double-crossover clones. Table 1. List of integration vectors. Accession number. First region of homology. Second region of homology. Element s between regions of homology. Open in new tab. Figure 1. Open in new tab Download slide. Figure 2.

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