Conjugation

Conjugation is a gradual, controllable process. A cytoplasmic connection between the two bacteria is established in the form of a narrow tube and further 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 forms a separate part of their genetic makeup (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 major chromosome. In the case of 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 part of the main chromosome (using insert sequences), in which case it is called an episome. The transferred part of the chromosome recombinates with the main chromosome of the recipient. 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 adhesins, which temporarily connect the cells to allow conjugation.

Related articles

 * Parasexual processes in bacteria
 * Transformation
 * Transdukce

Source

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


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