ABSTRACT
The microbial population of the rumen is diverse, and until the discovery of anaerobic fungi, it was believed to consist principally of anaerobic and facultatively anaerobic bacteria, ciliated protozoa, and flagellate protozoa. The development of an oxygen-resistant survival stage in dried feces has been demonstrated, but its nature is unknown. The fungal growth is normally tightly attached to digesta fragments. The life cycles of all anaerobic fungi so far described consist of an alternation between a motile, flagellate zoospore stage, free-living in the liquid phase of the digesta, and a nonmotile, vegetative, reproductive stage, saprophytic on digesta fragments in the alimentary tract of the animal. Consequently, transmission electron microscopy was used to confirm chytridiomycete taxonomy. Although much is known conerning the general biology, chemistry, and biochemistry of anaerobic fungi from the rumen, considerable gaps still exit in the knowledge.
