Pili

Pili are hair-like appendages found on the surface of many bacteria and archaea. They are also known as fimbriae. Pili are used by bacteria to attach to other bacteria and to animal cells, facilitating the transfer of DNA between cells in a process called conjugation. They also play a role in biofilm formation and bacterial pathogenesis.

Structure

Pili are composed of protein subunits called pilin. The pilin subunits are assembled into a helical structure by a process called polymerization. The length and number of pili can vary between different species of bacteria.

Function

Pili have several functions in bacteria. They are used for cell adhesion, allowing bacteria to attach to other cells or surfaces. This is important for biofilm formation and for the establishment of infections. Pili also play a role in DNA transfer between cells, a process known as conjugation. In addition, some types of pili can be used for twitching motility, a form of bacterial movement.

Types

There are several types of pili, including:

• Type IV pili: These are involved in twitching motility and biofilm formation.
• Sex pili: These are used for DNA transfer in the process of conjugation.
• Type I pili: These are involved in cell adhesion and are important for bacterial pathogenesis.

See also

• Flagellum
• Bacterial conjugation
• Biofilm
• Bacterial pathogenesis

References

Pili Resources
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