Envoy at 13:22, 17 May 2007

2007-05-17T13:22:02Z

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{{Taxobox
| color = lightblue
| name = Ergot
| image = Koeh-185.jpg
| image_width = 250px
| image_caption = ''Claviceps purpurea''
| regnum = [[Fungus|Fungi]]
| divisio = [[Ascomycota]]
| classis = [[Euascomycetes]]
| ordo = [[Hypocreales]]
| familia = [[Clavicipitaceae]]
| genus = '''''Claviceps'''''
| subdivision_ranks = [[Species]]
| subdivision =
About 50, including: 
''Claviceps africanum'' 
''Claviceps fusiformis'' 
''Claviceps paspali'' 
''Claviceps purpurea'' 
}}

'''Ergot''' is the common name of a [[fungus]] in the genus ''[[Claviceps]]'' that is parasitic on certain grains and grasses. The form the fungus takes to winter-over is called a [[sclerotium]], and this small structure is what is usually referred to as 'ergot', although referring to the members of the ''Claviceps'' genus as 'ergot' is also correct. There are about 50 known species of ''Claviceps'', most of them in the tropical regions. Economically important species are ''Claviceps purpurea'' (parasitic on [[Poaceae|grass]]es and cereals), ''C. fusiformis'' (on [[pearl millet]], buffel grass), ''C. paspali'' (on dallis grass), and ''C. africana''[http://www.apsnet.org/online/feature/ergot/0218-01F.pdf](on [[sorghum]]). ''C. purpurea'' can affect a number of cereals including [[rye]] (its most common host), [[triticale]], [[wheat]] and [[barley]]. It affects [[oat]]s only rarely.

There are three races or varieties of ''C. purpurea'', differing in their host specifity [http://www2.biomed.cas.cz/~pazouto/purpurea.htm]:
*G1 — land grasses of open meadows and fields;
*G2 — grasses from moist, forest, and mountain habitats;
*G3 (''C. purpurea'' var. ''spartinae'') — salt marsh grasses (''Spartina'', ''Distichlis'').

== Life cycle of the fungus ==

An '''ergot kernel''' called a sclerotium develops when a floret of flowering grass or cereal is infected by a [[spore]] of ''Claviceps '' fungus. The infection process mimics a [[pollen]] grain growing into an [[ovary (plants)|ovary]] during [[fertilization]]. The fungus then destroys the plant ovary and attaches itself to a [[vascular bundle]] originally intended for [[seed]] nutrition. The first stage of ergot infection manifests itself as a white soft tissue (known as [[sphacelia]]) producing sugary [[Honeydew (secretion)|honeydew]], which often drops out of the grass florets. This honeydew contains millions of [[asexual reproduction|asexual]] spores ([[conidia]]) which are dispersed to other florets by [[insect]]s. Later, the sphacelia convert into a hard dry sclerotium inside the husk of the floret. At this stage, [[alkaloid]]s and [[lipid]]s accumulate in the sclerotium.

''Claviceps '' species from tropic and subtropic regions produce macro- and microconidia in their honeydew. Macroconidia differ in shape and size between the species, whereas microconidia are rather uniform, oval to globose (5x3μm). Macroconidia are able to produce secondary conidia. A germ tube emerges from a macroconidium through the surface of a honeydew drop and a secondary conidium of the oval to pearlike shape is formed to which the contents of the original macroconidium migrates. Secondary conidia form white frost-like surface on honeydew drops and are spread by wind. No such process occurs in ''Claviceps purpurea'', ''Claviceps grohii'', ''Claviceps nigricans'', and ''Claviceps zizaniae'', all from North temperate regions.

When a mature sclerotium drops to the ground, the fungus remains dormant until proper conditions trigger its fruiting phase (onset of spring, rain period, etc.). It germinates, forming one or several [[fruiting bodies]] with head and [[stipe (mycology)|stipe]], variously colored (resembling a tiny [[mushroom]]). In the head, threadlike [[sexual reproduction|sexual]] spores are formed, which are ejected simultaneously, when suitable grass hosts are flowering. Ergot infection causes a reduction in the yield and quality of grain and hay produced, and if infected grain or hay is fed to livestock it may cause a disease called [[ergotism]].

Black and protruding sclerotia of ''C. pu
rpurea'' are well known. However, many tropical ergots have brown or greyish sclerotia, mimicking the shape of the host seed. For this reason, the infection is often overlooked.

== Effects on humans and animals ==
{{Main|Ergotism}}

Ergot contains alkaloids of the [[ergoline]] group, which have a wide range of activities including effects on [[circulatory system|circulation]] and [[neurotransmission]]. [[Ergotism]] is the name for the collection of symptoms a human or animal has when it has ingested too much of this fungus. Ergotism went also under the name "St. Anthony's fire" hinting at burning sensations in the limbs[http://www.medicinenet.com/script/main/art.asp?articlekey=14891]. Another effect of ergot alkaloids is [[vasoconstriction]], therefore ergotism may lead to [[gangrene]] and loss of the limbs due to limited blood circulation. This may also cause insanity, convulsions, or death, due to limited circulation to the [[brain]]. Other symptoms include strong [[uterus|uterine]] contractions, [[nausea]], [[seizure]]s, and unconsciousness. Monks of the order of St. [[Anthony the Great]] specialized in treating ergotism victims with balms containing tranquilizing and blood circulation-stimulating plants; they were also skilled in amputations. Entire villages have been known to suffer ergotism after the village bakery used infected grain.

In addition to ergot alkaloids, ''Claviceps paspali'' also produces [[tremorgen]]s (paspalitrem) causing "paspalum staggers" in cattle.

Historically, controlled doses of ergot were used to induce [[abortion]]s and to stop maternal bleeding after childbirth, but simple ergot extract is no longer used as a [[pharmaceutical]].

Among those who studied ergot and its derivatives was [[Albert Hofmann]], whose experiments led to the discovery of [[LSD]], a powerfully [[Psychedelics, dissociatives and deliriants|hallucinogenic]] ergot derivative that affects the [[serotonin]] system. Contrary to some rumors, ergot contains no LSD, but there are links between the two substances:

* [[LSD]] was first synthesized during research on the active ingredients of ergot.
* [[Lysergic acid]], a raw material used in the synthesis of LSD, was and still is prepared from ergot.

In the [[January 4]], [[2007]] edition of the [[New England Journal of Medicine]], a paper was released documenting a British study of over 11,000 [[Parkinson's Disease]] patients, which found that two commonly used Parkinson's drugs derived from ergot, [[Pergolide]] and [[Cabergoline]], may increase the risk of leaky heart valves by up to 700%. Italian researchers taking echocardiograms of 155 patients also determined that up to 1/3rd of the patients who took either of the two drugs could develop leaky heart valves. Heart valve problems cause shortness of breath and fatigue, two symptoms commonly shared with [[Parkinson's Disease]].

== Speculations ==
[[Image:Ergot01.jpg|thumb|Ergot on wheat spikes]]

The disease cycle of the ergot fungus was first described in the [[1800s]], but the connection with ergot and epidemics among people and animals was known several hundred years before that.

Human poisoning due to the consumption of rye bread made from ergot-infected grain was common in Europe in the [[Middle Ages]]. The epidemic was known as [[St. Anthony's Fire]] or [[ignis sacer]].

It has also been posited — though speculatively — that the [[Salem Witch Trials]] were initiated by young women who had consumed ergot-tainted rye. The [[Great Fear]] in France during the [[French Revolution|Revolution]] has also been linked by some historians to the influence of ergot.

Poisonings due to consumption of seeds treated with [[Mercury (element)|mercury]] compounds are sometimes misidentified as ergotism, such as the case of mass-poisoning in the French village [[Pont-Saint-Esprit]] in 1951:
<blockquote>
The mass poisoning which took place in the French town of Pont-St. Esprit in 1951 has been widely presented in the lay and scientific press as an example of ergotism. While the poisoning was traced to bread, ergotism was
not the cause of the syndrome, which was due to a toxic mercury compound used to disinfect grain to be planted as seed. Some sacks of grain treated with the fungicide were inadvertently ground into flour and baked into bread. [[Albert Hofmann]] arrived at this conclusion after visiting Pont-St. Esprit, and analyzing samples of the bread (which contained no ergot alkaloids) and autopsy samples of four of the victims who succumbed (Hofmann 1980; Hofmann 1991). On the other hand, Swedish toxicologist Bo Holmstedt insists the poisoning was in fact due to ergotism (Holmstedt 1978)…<ref>[[Jonathan Ott]], ''Pharmacotheon: Entheogenic Drugs, their Plant Sources and History'' (Kennewick, W.A.: Natural Products Co., 1993), pg. 145. See also Dr. [[Albert Hofmann]], ''LSD: My Problem Child'' (New York, N.Y.: McGraw-Hill Book Company, 1980), [http://www.lycaeum.org/books/books/my_problem_child/chapter1.html Chapter 1: "How LSD Originated," pg. 6.]</ref>
</blockquote>
As Dr. Simon Cotton (member of the Chemistry Department of [[Uppingham School]], U.K.) notes, there have been numerous cases of mass-poisoning due to consumption of [[Mercury (element)|mercury]]-treated seeds:
<blockquote>
More horrifying than this were epidemics of poisoning, caused by people eating treated seed grains. There was a serious epidemic in Iraq in 1956 and again in 1960, whilst use of seed wheat (which had been treated with a mixture of C2H5HgCl and C6H5HgOCOCH3) for food, caused the poisoning of about 100 people in West Pakistan in 1961. Another outbreak happened in Guatemala in 1965. Most serious was the disaster in Iraq in 1971–2, when according to official figures 459 died. Grain had been treated with methyl mercury compounds as a fungicide and should have been planted. Instead it was sold for milling and made into bread. It had been dyed red as a warning and also had warning labels in English and Spanish that no one could understand.<ref>See Simon Cotton, B.Sc., Ph.D., [http://www.chm.bris.ac.uk/motm/dimethylmercury/dmmh.htm "Dimethylmercury and Mercury Poisoning"], ''Molecule of the Month'' (''[http://www.chm.bris.ac.uk/motm/motm.htm MOTM]''; published on the School of Chemistry, [[University of Bristol]], U.K. website), October 2003.</ref>
</blockquote>

[[Kykeon]], the beverage consumed by participants in the ancient Greek mystery of [[Eleusinian Mysteries]], might have been based on hallucinogens from ergot.

Currently, [[rye]] grain is infected repeatedly to produce ergot.

==See also==

== Notes ==

<references/>

== External links ==
{{commons|Claviceps purpurea|Ergot}}

* http://www.entheology.org/edoto/anmviewer.asp?a=37&z=5
* http://www.ext.nodak.edu/extpubs/plantsci/crops/pp551w.htm
* [http://www.pubmedcentral.gov/articlerender.fcgi?tool=pubmed&pubmedid=15933008 Abundant Respirable Ergot Alkaloids from the Common Airborne Fungus Aspergillus fumigates]
* [http://www.pbs.org/wnet/secrets/case_salem/index.html PBS Secrets of the Dead: "The Witches Curse" (concerning the Salem trials and ergot)]
* [http://content.nejm.org/cgi/content/short/356/1/29 New England Journal of Medicine - Dopamine Agonists and the Risk of Cardiac-Valve Regurgitation]
* [http://www.healthday.com/Article.asp?AID=600564 HealthDay - Parkinson's Drugs Can Damage Heart Valves]

{{Ergolines}}

[[Category:Ascomycetes]]
[[Category:Psychoactive mushrooms]]
[[Category:Natural sources of lysergamides]]
[[Category:Medicinal fungi]]
[[Category:Parasitic fungi]]
[[Category:Plant diseases]]
[[Category:Cereal diseases]]
[[Category:Barley diseases]]
[[Category:Rye diseases]]
[[Category:Triticale diseases]]
[[Category:Wheat diseases]]
[[Category:Abortifacients]]

Ergot - Revision history

Envoy at 13:22, 17 May 2007