capsule

views updated

capsule
1. The gelatinous, outer surface layer of a prokaryotic cell (also known as the sheath in cyanobacteria), which is composed primarily of polysaccharides. In pathogenic bacteria, and possibly in others, it appears to serve a protective function against the defensive mechanism of the host, since such bacteria become non-infective in its absence.

2. The spore-bearing structure of a moss or liverwort.

3. A dry fruit, normally dehiscent.

More From encyclopedia.com