Axial filament is a term used to describe a structure found in certain bacteria known as spirochetes. The word "axial" is pronounced /ˈæksiəl/ (AK-see-uhl), with stress on the first syllable. "Filament" is pronounced /ˈfɪləmənt/ (FIL-uh-muhnt), with stress on the second syllable. Together, the term is pronounced /ˈæksiəl ˈfɪləmənt/ (AK-see-uhl FIL-uh-muhnt). The "x" in "axial" is pronounced like a "ks" sound and the "t" at the end of "filament" is silent. The IPA phonetic transcription helps explain the pronunciation and spelling of this word.
The term "axial filament" refers to a cellular structure found in certain microorganisms, particularly in spiral-shaped bacteria known as spirochetes. It is a long, helically shaped filament that runs along the length of the cell, inside its outer sheath. The axial filament is primarily involved in the movement or motility of the spirochete.
The axial filament is composed of a bundle of tightly wound flagella, which are thread-like appendages responsible for locomotion. Unlike typical flagella found in other bacteria, these flagella are located within the periplasmic space, the region between the outer and inner membranes of the cell. The flagella constantly rotate in opposite directions, generating a twisting motion that propels the spirochete forward. This unique arrangement allows the spirochete to move in a corkscrew manner, providing it with remarkable agility and enabling it to navigate through viscous environments, such as bodily fluids or mucus layers.
The axial filament is a crucial component for the virulence and pathogenicity of certain spirochetes, as it assists in their colonization and invasion of host tissues. Examples of spirochetes that possess an axial filament include Treponema pallidum, the causative agent of syphilis, and Borrelia burgdorferi, which causes Lyme disease.
In summary, the axial filament is a specialized structure found in spirochetes, consisting of tightly wound flagella within the periplasmic space. It enables the spirochetes to exhibit their unique corkscrew-like motility, aiding in their colonization and pathogenicity.
The central fibril of the fiagellum of a spermatozoon.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.
The word "axial" is derived from the Latin word "axis" meaning "axle" or "central line", which itself traces back to the Greek word "axios" meaning "worthy". "Filament" comes from the Latin word "filum" meaning "thread" or "string". Therefore, the term "axial filament" likely originated from the combination of these two root words, referring to a thread-like structure or filament that is situated along the central line or axis.