Home »

Ophiocordyceps unilateralis

The meaning of «ophiocordyceps unilateralis»

Torrubia unilateralis Tul. (1865) Cordyceps unilateralis (Tul.) Sacc. (1883)

Ophiocordyceps unilateralis is an insect-pathogenic fungus, discovered by the British naturalist Alfred Russel Wallace in 1859, and currently found predominantly in tropical forest ecosystems. O. unilateralis infects ants of the tribe Camponotini, with the full pathogenesis being characterized by alteration of the behavioral patterns of the infected ant. Infected hosts leave their canopy nests and foraging trails for the forest floor, an area with a temperature and humidity suitable for fungal growth; they then use their mandibles to attach themselves to a major vein on the underside of a leaf, where the host remains after its eventual death.[2] The process leading to mortality takes 4–10 days, and includes a reproductive stage where fruiting bodies grow from the ant's head, rupturing to release the fungus's spores. O. unilateralis is, in turn, also susceptible to fungal infection itself, an occurrence that can limit its impact on ant populations, which has otherwise been known to devastate ant colonies.

Ophiocordyceps unilateralis and related species are known to engage in an active secondary metabolism, among other reasons, for the production of substances active as antibacterial agents that protect the fungus-host ecosystem against further pathogenesis during fungal reproduction. Because of this secondary metabolism, an interest in the species has been taken by natural products chemists, with corresponding discovery of small molecule agents (e.g. of the polyketide family) of potential interest for use as human immunomodulatory, anti-infective, and anticancer agents.

After years of research, the taxonomy of Ophiocordyceps unilateralis is becoming increasingly clear.

Throughout history there has been confusion about the distinction between the genera Cordyceps and Ophiocordyceps. There have been many debates about whether the zombie-ant fungus (and other fungi) belonged to one or to the other as Ophiocordyceps was only recently brought forward.

The genus Cordyceps comprises over 400 species, historically classified in the family Clavicipitaceae within the order Hypocreales. The classification was based on different morphological characteristics such as filiform ascospores and cylindrical asci.[3] When Cordyceps were first classified, there was no concrete evidence for the genus Ophiocordyceps. However, in 2007, important new molecular data was tested, and enabled them to reorganize the family Clavicipitaceae. It was found that Clavicipitaceae was in fact three distinct monophyletic families: the Clavicipitaceae, the Cordycipitaceae and the Ophiocordycipitaceae.[3]

The new molecular phylogenetics studies contradicted the older classification and moved all Cordyceps species forming a sister group with Tolypocladium, into Ophiocordycipitaceae. Fungi able to parasitize ants were also included in the transfer, such as Cordyceps unilateralis which was later renamed Ophiocordyceps unilateralis.[4] Following this study, multiple traits such as the production of darkly pigmented, hard to flexible stromata were defined as characteristics of the family Ophiocordycipitaceae.[4]

© 2015-2020, Wikiwordbook.info
Copying information without reference to the source is prohibited!
contact us mobile version