Scanning electron microscopy and the direct plating technique were used to investigate the in situ morphology, distribution and number of bacteria associated with egg capsules (cocoons) of the earthworm, Eisenia fetida. Results from direct plating of egg capsule homogenates indicated that there were up to 108 total bacterial colony forming units per g cocoon. Scanning electron microscopy of cocoon fragments revealed numerous rod-shaped microorganisms, probably bacteria, that were associated with the developing juvenile worm. The microorganisms, measuring 1-2 μm in length and 0.3-0.6 μm in diameter, could be seen as dense mats in the presence of a mucoid material within internal structures, and on juvenile worm surfaces. The microorganisms found associated with the developing earthworm epithelium were seen as bundles oriented in a palisades (side-to-side) configuration which were perpendicular to the juvenile worm surface. The microorganisms present did not appear to be pathogenic to the developing earthworm tissue, which suggests a mutualistic association. To our knowledge, this is the first investigation of earthworm egg capsules using scanning electron microscopy.
|Original language||English (US)|
|Number of pages||9|
|State||Published - Feb 1998|
- Egg capsules
- Eisenia fetida