Spirochete Bacteria

Endoflagella and Spirochetes

Endoflagella are bundles of flagella called axial filaments that wrap around the cell body of spirochetes. The axial filaments cause the bundles of flagella to rotate to help the spirochete move in a twisting motion. The term endoflagella has the prefix 'endo' which means inside, and flagella in bacteria are used for movement of the cell, so endoflagella are flagella enclosed inside a membrane that help the spirochete move. Flagella have many functions, the most common being movement. They are also sensory and can depict changes in pH and temperature. Flagella (singular flagellum), meaning whip, are long whip-like structures that resemble long hair that propel the cell through a liquid medium. Although several species of prokaryotes have flagella, flagella can also be found in other types of cells such as human sperm cells. The endoflagella and axial filament are specific to spirochetes and the presence of these structures determines spirochete classification.

Spirillum Vs. Spirochete

Spirochetes are prokaryote bacteria characterized by a species-specific endoflagella and axial filament that gives the spirochete its unique spiral/twisting locomotion (movement) style. Spirochetes are a spiral-shaped bacteria with axial filaments "wrapped" around the cell body that propel the spirochete in a twisting motion. Spirillum bacteria in comparison to spirochete bacteria are spiral-shaped bacteria with flagella, similar to the corkscrew-shaped spirochete, but do not contain an endoflagella or an axial filament for locomotion. Spirillum move by flagella that move in a twisting motion to propel the spirillum forward. Spirochetes use an axial filament that rotates the cell body to propel the bacteria in a forward motion.

Prokaryotes (Bacteria that do not contain membrane organelles, including a nucleus.) are found in a variety of shapes including spiral, coccus, bacillus and vibrio. Spirillum bacteria are found in a spiral shape, similar to spirochetes. Coccus bacteria are sphere or round shaped. Bacillus bacteria are rod shaped. Vibrio bacteria are comma shaped.

Bacteria shapes

Spirochetes Examples

Spirochete examples can be beneficial (mutualistic) or parasitic. Some examples of spirochetes that are parasitic belong to the families of Treponema, Leptospira and Borrelia. Parasitic spirochetes cause diseases such as syphilis, yaws and Lyme disease. Some examples of mutualistic spirochetes are found in termites, mollusks and ruminants, such as cows. Beneficial spirochetes are useful for the host they infect such as aiding in digestion, making nutrients or helping to feed their hosts. Spirochetes are 5-15 microns long and about 0.2 microns wide in the family Treponema and 5-15 microns long and about 0.1 microns wide in the family Leptospira.

Mutualism and Spirochetes Examples

Mutualism is a type of symbiosis in which both organisms benefit from the relationship. Mixotricha paradoxa spirochetes have a mutualistic relationship with Australian termites in which the termites benefit from the spirochetes by helping the termites digest the cellulose found in wood. The spirochete converts cellulose into an energy source the termites can use. Spirochetes also take nitrogen from the atmosphere and convert it into nutrients. These spirochetes are not the same shape as other spirochetes. Scientists have found that the spirochetes involved in this mutualistic relationship are rod shaped and do not use endoflagella for locomotion.

In addition to the mutualistic relationship between termites and spirochetes, other beneficial spirochetes are found in ruminants such as cows. These spirochetes aid ruminant digestion. Other harmless spirochetes are found in mussels and oysters. These spirochetes act as cilia, hairlike projections on the outside of bacteria, to help move food into the mussels and oysters.

Parasitism and Spirochetes Examples

Parasitic spirochetes cause a variety of diseases, especially in humans. The three main families that include parasitic spirochetes are Treponema, Leptospira and Borrelia. Several diseases caused by parasitic spirochetes include syphilis, Lyme disease, relapsing fever, leptospirosis and yaws. Most spirochetes are associated with a host cell and can be beneficial (mutualistic) or parasitic.

• Syphilis is caused by the spirochete Treponema pallidum, which is a sexually transmitted disease in humans.
• Lyme disease is caused by a spirochete called Borrelia burgdorferi . Lyme disease is carried by a specific tick, Ixodes scapularis, which transmits Lyme disease to humans. This disease is characterized by a bull's eye, solid or ring-like rash around the bite area.
• Relapsing fever is caused by the Borrelia species of spirochetes. Relapsing fever is a fever that recurs several times and is caused by bites from ticks or body lice.
• Leptospirosis is caused by Leptospiraceae interrogans and includes symptoms such as fever, headache and myalgia (muscle pain).
• Yaws is a skin infection that causes lumps and ulcers, most commonly in children. It is caused by the spirochete Treponema pallidum.

Bullseye rash linked to Lyme disease

Spirochetemia

Spirochetemia is the presence of spirochetes in the blood. An example of spirochetemia is caused by the spirochete Leptospira interrogans which gives rise to leptospirosis. Leptospirosis is usually a mild disease characterized by fever, myalgia (muscle pain) and headache, but if left to progress, can lead to liver or kidney failure. Letospirosis has several reservoir hosts, but the most common is the brown rat. Treatment can include antibiotics, but human immune response can usually clear the infection.

Lesson Summary

Spirochetes are corkscrew-shaped bacteria characterized by an endoflagella which is part of the axial filament. Endoflagella form axial filaments. Axial filaments help the spirochete move through rotation of the endoflagella which gives the spirochete a rotating-type motion. Spirillum bacteria in comparison to spirochete bacteria are spiral-shaped bacteria, similar to the corkscrew-shaped spirochete, but spirillum do not contain an endoflagella or an axial filament for locomotion. Spirillum move by flagella that move in a twisting motion to propel the spirillum forward.

The three main families that include parasitic spirochetes are Treponema, Leptospira and Borrelia. Most spirochetes are associated with a host cell and can be mutualistic (beneficial) or parasitic. Mutualism is a type of symbiotic relationship in which both organisms benefit from the relationship. Syphilis is caused by the spirochete Treponema pallidum and is a sexually transmitted disease in humans. Lyme disease is caused by the spirochete Borrelia burgdorferi and is passed to humans through a tick bite. Relapsing fever is caused by the Borrelia species of spirochetes, and that causes several episodes of fever. Leptospirosis is caused by Leptospiraceae interrogans and is characterized by flu-like symptoms. Spirochetemia, the presence of spirochetes in the blood, can also lead to leptospirosis. Yaws is caused by Treponema pallidum and is a skin infection that causes lumps and ulcers, most commonly in children.