Conjugation

Conjugation is a gradual, controllable process. A cytoplasmic connection between the two bacteria involved in the process is established in the form of a narrow tube. Afterward, a part or all of the genome is transferred from the donor cell to the recipient cell.

The presence of sex chromatin (F-factor) determines the ability to transfer part of its genetic equipment to another bacterium. F-factor is encoded on a plasmid (F-plasmid). We call such cells F + and they are always donors of genetic information. F factor genes determine the formation of fimbriae (F-pili) on the surface, which allows contact between bacteria. The F + bacterium specifically binds to the surface of the recipient bacterium and transfers a single strand of its F-plasmid to it. The second strand is then synthesized in both bacteria.

The F plasmid replicates independently of the cell's chromosome. After F-plasmid transfer, the F - cell transforms into an F + cell and is also able to pass on its genetic information. The F plasmid may be integrated into the main chromosome (using insert sequences). The transferred part of the chromosome of a donor cell can recombine with the main chromosome of the recipient cell. Such cells show a high frequency of gene recombination and are referred to as Hfr bacteria.

The described process is typical for gram-negative bacteria. Gram-positive bacteria do not use pili, but instead use adhesins, which temporarily connect the cells to allow conjugation.

References

Related articles

• Horizontal gene transfer in bacteria
  • Transformation
  • Transduction

Source

• ŠTEFÁNEK, Jiří. Medicine, diseases, study at the 1st Faculty of Medicine, Charles University  [online]. [feeling. 14.03.2010]. < https://www.stefajir.cz/ >

References

• JULÁK, Jaroslav. Introduction to medical bacteriology. 1st edition. Prague: Karolinum, 2006.  ISBN 80-246-1270-4 .

• KOHOUTOVA, Milada. Medical Biology and Genetics (Part II). 1st edition. Praha: Nakladatelství Karolinum, 2013. 202 pp.  ISBN 978-80-246-1873-9 .