User:Akiegami: Difference between revisions
| Line 62: | Line 62: | ||
==References== | ==References== | ||
[“Taxonomy Browser Taxonomy Browser (Ophiocordyceps Unilateralis).” Nih.gov, 2020, www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?searchTerm=Ophiocordyceps+unilateralis&searchMode=complete+name&lock=1&unlock=1&command=search.] | [“Taxonomy Browser Taxonomy Browser (Ophiocordyceps Unilateralis).” Nih.gov, 2020, www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?searchTerm=Ophiocordyceps+unilateralis&searchMode=complete+name&lock=1&unlock=1&command=search.] | ||
| | ||
Revision as of 20:04, 15 December 2025
Ophiocordyceps unilateralis
Domain: Eukarya
Phylum: Ascomycota
Class: Sordariomycetes
Order: Hypocerales
Family: Ophiocordycipitaceae
Species
|
NCBI: [1] |
Ophiocordyceps unilateralis
Ophiocordyceps unilateralis s.l.
Background
Ophiocordyceps unilateralis was first discovered by biologist Alfred Russel Wallace in 1859 (Hughes et. Al 2011). The fungus was further described by Louis and Charles Tulasne who drew illustrations of it infecting ants (Evans et. Al 2017). Scientific papers often refer to this fungus as Ophiocordyceps unilateralis s.l (sensu lato - in a broad sense) due to the fact that it is actually a species complex (Evans et. Al 2011). Ophiocordyceps unilateralis s.l infects Campotini ants, turning them into zombies and utilizing them as tools for propagation (Hughes et. Al 2011, Evans et. Al 2017). Numerous studies have focused on characterizing the infection mechanisms and secondary metabolites produced by this fungus in order to better understand how it manipulates its ant hosts (Hughes et. Al 2011, Bekker et. Al 2017). Ophiocordyceps unilateralis s.l is commonly found in tropical forest environments throughout the world in countries such as the United States, Thailand, Japan, and Brazil (Evans et. Al 2011; Lin et. Al 2020).
Morphology
Ophiocordyceps unilateralis s.l produces both sexual and asexual structures. The teleomorph of this fungus is defined by the production of a clava on the back of the head with a stromal plate (Evans et. Al 2011). Embedded into the stromal plates are numerous ascomata which produce ascospore containing asci (Evans et. Al 2011). On the other hand, different variations of the anamorph exist with one example being the sporodochium which are dense hyphal masses with conidia (Evans et. Al 2017; Henry et. Al 2023). However, the morphological characteristic that sets Ophiocordyceps unilateralis s.l apart from all other ant-infecting fungi is the fact that they produce both type A and B phialides on the hymenium of their stromatal clava (Evans et Al. 2017).
As previously mentioned, Ophiocordyceps unilateralis s.l is a species complex so it's not surprising that there are morphological variations amongst its members. Below are morphological descriptions of several Ophiocordyceps unilateralis s.l members found in Brazil.
Ophiocordyceps campotini-rufipedis
Ophiocordyceps campotini-rufipedis produces dense silky white mycelium that turns brown as time passes (Evans et. Al 2011). It produces 5mm-8mm stromata with a dark brown base and a pink fertile region which darkens as it ages (Evans et. Al 2011).
Ophiocordyceps campotini-balzani
Ophiocordyceps campotini-balzani produces chocolate brown mycelium cushions on the joints of the ants legs or antennae (Evans et. Al 2011). Like Ophiocordyceps campotini-rufipedis, its stromata has a dark brown base but it also has a dark brown fertile region which turns black as it ages (Evans et. Al 2011).
Ophiocordyceps campotini-melanotici
Ophiocordyceps campotini-melanotici produces sparsely distributed chocolate brown hyphae (Evans et. Al 2011). The morphology of its stromata is identical to that of Ophiocordyceps campotini-balzani (Evans et. Al 2011).
Genome Structure
Because Ophiocordyceps unilateralis s.l is a species complex, there is a considerable amount of variation in the genome structure. A study conducted in 2024 found that the genome size of seven Ophiocordyceps unilateralis s.l specimens ranged from 27.80 to 51.00 mb with the GC content ranging from 41.81-53.22% (Lu et. Al 2024). The same study also found that the variation in total number of genes, which ranged from 6700 to 6974, was relatively small (Lu et. Al 2024). Yet, another study found that the genome structure of a South Carolinian Ophiocordyceps unilateralis s.l specimen was around 26.05 mb with 7831 putative genes (Bekker et. Al 2015). The bottom line is that the genome structure of this species complex varies quite a lot from specimen to specimen.
Ecology and Pathogenesis
Ophiocordyceps unilateralis s.l is a parasite that primarily infects Golden Carpenter ants from the Campotini tribe (Lin et. Al 2020). Recent studies, however, demonstrated that a member of this species complex could sympatrically infect ant species from the Polyrachis and Camponotus genera, strongly suggesting that this species complex has a broader range of hosts (Lin et. Al 2020).
The main objective of Ophiocordyceps unilateralis s.l pathogenesis is propagation (Lin et. Al 2020). Ophiocordyceps unilateralis s.l begins by utilizing ascospores to infect ants wandering around on the forest floor (Lin et. Al 2020). It is thought that some sort of signaling or host recognition factor mechanism initiates the production of enzymes and other infection mechanisms to penetrate the exoskeleton of the ant (Evans et. Al 2011). Experimental data suggests that Ophiocordyceps unilateralis s.l utilizes secondary metabolites to control the behavior of the ant, directing it to climb up plants (Lu et. Al 2024, Lin et. Al 2020). Once on the underside of leaves/twigs, Ophiocordyceps unilateralis s.l induces the famous “death grip” wherein the ant is forced to bite and hang onto major veins in the leaf (Lin et. Al 2020). Rhizoids and mycelial structures are produced by the fungus to further secure it in place (Lin et. Al 2020). Some researchers think that the death grip mechanism occurs specifically on the leaf veins so that the fungus can use nutrients from the plant vascular system for growth purposes (Lin et. Al 2020). It takes about one to two weeks for Ophiocordyceps unilateralis s.l to produce fruiting structures from the dead ant so that more ascospores can be released onto the forest floor enabling the infection cycle to continue (Lin et. Al 2020). One interesting thing to note is that Ophiocordyceps unilateralis s.l produces both hyphae and yeast-like cells for structural support during its growth stage on the dead ant (Andersen et. Al 2009).
From an ecological perspective, Ophiocordyceps unilateralis s.l holds great importance as it gives us useful insight into the different types of host-microbe interactions that occur in rainforests (Evans et. Al 2011). A lot is still unknown about the Ophiocordyceps unilateralis s.l species complex so more research needs to be done for a better understanding of its ecosystem functioning (Evans et. Al 2011).
Secondary Metabolites
Secondary metabolites play an important role in the Ophiocordyceps unilateralis s.l infection cycle as they can aid in behavioral manipulation of ant hosts (Lu et. Al 2024). Genomic analysis of Ophiocordyceps unilateralis s.l members revealed potential production of NG-391, lucilacene, higginsianin B, pyripyropene A, and pyranonigrin E (Lu et. Al 2024). Some of these compounds possess medically relevant properties with higginsianin B being the most notable one as it exhibits both anti-cancer properties and low cytotoxicity (Lu et. Al 2024). Further research in this area could reveal more Ophiocordyceps unilateralis s.l derived secondary metabolites with diverse functions and potential applications in industries such as agriculture, medicine and many more.
References
[“Taxonomy Browser Taxonomy Browser (Ophiocordyceps Unilateralis).” Nih.gov, 2020, www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?searchTerm=Ophiocordyceps+unilateralis&searchMode=complete+name&lock=1&unlock=1&command=search.] [Andersen, Sandra B., et al. “The Life of a Dead Ant: The Expression of an Adaptive Extended Phenotype.” The American Naturalist, vol. 174, no. 3, Sept. 2009, pp. 424–433, https://doi.org/10.1086/603640.]
[Bekker, Charissa de, et al. “Ant-Infecting Ophiocordyceps Genomes Reveal a High Diversity of Potential Behavioral Manipulation Genes and a Possible Major Role for Enterotoxins.” Scientific Reports, vol. 7, no. 1, 2 Oct. 2017, pp. 1–13, https://doi.org/10.1038/s41598-017-12863-w.]
[Evans, H.C., et al. “Epitypification and Re-Description of the Zombie-Ant Fungus, Ophiocordyceps Unilateralis (Ophiocordycipitaceae).” Fungal Systematics and Evolution, vol. 1, no. 1, 1 June 2017, pp. 13–22, https://pmc.ncbi.nlm.nih.gov/articles/PMC7274273/.]
[Evans, Harry C, et al. “Ophiocordyceps Unilateralis: A Keystone Species for Unraveling Ecosystem Functioning and Biodiversity of Fungi in Tropical Forests?” Communicative & Integrative Biology, vol. 4, no. 5, 1 Sept. 2011, pp. 598–602, www.ncbi.nlm.nih.gov/pmc/articles/PMC3204140/]
[Evans, Harry C., et al. “Hidden Diversity behind the Zombie-Ant Fungus Ophiocordyceps Unilateralis: Four New Species Described from Carpenter Ants in Minas Gerais, Brazil.” PLoS ONE, vol. 6, no. 3, 2 Mar. 2011, p. e17024, https://doi.org/10.1371/journal.pone.0017024.]
[Henry, Peter M, et al. “Sporodochia Formed by Fusarium Oxysporum F. Sp. Fragariae Produce Airborne Conidia and Are Ubiquitous on Diseased Strawberry Plants in California.” Phytopathology, vol. 113, no. 8, 20 Mar. 2023, pp. 1399–1404, https://doi.org/10.1094/phyto-10-22-0375-sc.]
[Hughes, David P, et al. “Behavioral Mechanisms and Morphological Symptoms of Zombie Ants Dying from Fungal Infection.” BMC Ecology, vol. 11, no. 1, 9 May 2011, p. 13, bmcecol.biomedcentral.com/articles/10.1186/1472-6785-11-13, https://doi.org/10.1186/1472-6785-11-13.]
[Lin, Wei-Jiun, et al. “Evaluating the Tradeoffs of a Generalist Parasitoid Fungus, Ophiocordyceps Unilateralis, on Different Sympatric Ant Hosts.” Scientific Reports, vol. 10, no. 1, 14 Apr. 2020, https://doi.org/10.1038/s41598-020-63400-1.]
[Lu, Yingling, et al. “Genomic Comparative Analysis of Ophiocordyceps Unilateralis Sensu Lato.” Frontiers in Microbiology, vol. 15, 15 Apr. 2024, https://doi.org/10.3389/fmicb.2024.1293077.]
Author
Page authored by Aki Egami, student of Dr. Marc Orbach, University of Arizona .
