Neocallimastigomycota is a division of anaerobic fungi, found in the digestive tracts of herbivores. It encompasses only one family.
Discovery
The fungi in Neocallimastigomycota were first described by Orpin in 1975, based on motile cells present in the rumen of sheep. Although the cells were first believed to be flagellates, it has since been shown that they are fungi related to the core chytrids. Prior to this, the microbial population of the rumen was believed to consist only of bacteria and protozoa. Since their discovery they have been isolated from the digestive tracts of over 50 herbivores, including ruminant and non-ruminant mammals and herbivorous reptiles.
Reproduction and growth
These fungi reproduce in the stomach of ruminants through the use of zoospores that bears a kinetosome but lacks the nonflagellated centriole known in most chytrids, and have been known to utilize horizontal gene transfer in their development of xylanase (from bacteria) and other glucanases. The nuclear envelopes of their cells are notable for remaining intact throughout mitosis.
Metabolism
Neocallimastigomycota lack mitochondria. Using hydrogenosomes to oxidize NADH to NAD+, they release H2 as a product.
Polysaccharide-degrading activity
Neocallimastigomycota play an essential role in fibre-digestion in their host species. They are present in large numbers in the digestive tracts of animals which are fed on high fibre diets. The polysaccharide degrading enzymes produced by anaerobic fungi can hydrolyse the most recalcitrant plant polymers and can degrade unlignified plant cell walls entirely. The polysaccharide degrading enzymes are organised into a multiprotein complex, similar to the bacterial cellulosome
Spelling of name
The Greek termination, "-mastix", referring to "whips", i.e. the many flagella on these fungi, is changed to "-mastig-" when combined with additional terminations in Latinized names. The family name Neocallimastigaceae was originally incorrectly published as "Neocallimasticaceae" by the publishing authors which led to the coinage of the misspelled, hence incorrect "Neocallimasticales", an easily forgiven error considering that other "-ix" endings such as Salix goes to Salicaceae. Correction of these names is mandated by the International Code of Botanical Nomenclature, Art. 60. The corrected spelling is used by Index Fungorum. Both spellings occur in the literature and on the WWW as a result of the spelling in the original publication.
References
External links
- Neocallimastigomycota at the US National Library of Medicine Medical Subject Headings (MeSH)
- NIH
0 komentar :
Posting Komentar