Related Experiment Videos
Cell-associated levan of Actinomyces viscosus
Infection and Immunity
|February 1, 1978
Summary
Actinomyces viscosus cells can form a tenacious levan capsule when exposed to sucrose. Glucose-grown bacteria readily form this capsule, while sucrose-grown cells exhibit a less defined, loosely associated levan layer.
Area of Science:
- Microbiology
- Bacterial Cell Wall Structure
- Carbohydrate Metabolism
Background:
- Actinomyces viscosus is a bacterium known for its role in oral health.
- Levan is a type of polysaccharide that can be produced by bacteria.
- Understanding bacterial surface structures is crucial for studying microbial interactions.
Purpose of the Study:
- To investigate the presence and characteristics of cell-associated levan in Actinomyces viscosus.
- To determine the effect of different growth conditions (glucose vs. sucrose) on levan production.
- To characterize the nature of levan association with the bacterial cell surface.
Main Methods:
- Absorption of myeloma proteins with antilevan activity.
- Direct immunofluorescence microscopy.
- Cultivation of Actinomyces viscosus on glucose and sucrose media.
- Measurement of levan content relative to cell dry weight.
Main Results:
- Levan was not detected on the surface of glucose-grown A. viscosus.
- Incubation of glucose-grown cells with sucrose resulted in encapsulation with tenaciously adhering levan (0.02-0.03% of cell dry weight).
- Sucrose-grown A. viscosus cells showed low levels of cell-associated levan, forming a loose slime rather than a tenacious capsule.
Conclusions:
- Actinomyces viscosus can synthesize and tenaciously adhere levan to its cell surface upon exposure to sucrose.
- Growth conditions significantly influence the amount and structure of cell-associated levan.
- The formation of a levan capsule may play a role in bacterial adhesion or protection.