''Claviceps purpurea'' is an

ergot Ergot ( ) or ergot fungi refers to a group of fungi of the genus ''Claviceps''. The most prominent member of this group is '' Claviceps purpurea'' ("rye ergot fungus"). This fungus grows on rye and related plants, and produces alkaloids that c ...

fungus A fungus (: fungi , , , or ; or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and mold (fungus), molds, as well as the more familiar mushrooms. These organisms are classified as one ...

that grows on the

ear In vertebrates, an ear is the organ that enables hearing and (in mammals) body balance using the vestibular system. In humans, the ear is described as having three parts: the outer ear, the middle ear and the inner ear. The outer ear co ...

s of

rye Rye (''Secale cereale'') is a grass grown extensively as a grain, a cover crop and a forage crop. It is grown principally in an area from Eastern and Northern Europe into Russia. It is much more tolerant of cold weather and poor soil than o ...

and related

cereal A cereal is a grass cultivated for its edible grain. Cereals are the world's largest crops, and are therefore staple foods. They include rice, wheat, rye, oats, barley, millet, and maize ( Corn). Edible grains from other plant families, ...

and

forage Forage is a plant material (mainly plant leaves and stems) eaten by grazing livestock. Historically, the term ''forage'' has meant only plants eaten by the animals directly as pasture, crop residue, or immature cereal crops, but it is also used m ...

plants. Consumption of

grain A grain is a small, hard, dry fruit (caryopsis) – with or without an attached husk, hull layer – harvested for human or animal consumption. A grain crop is a grain-producing plant. The two main types of commercial grain crops are cereals and ...

s or seeds contaminated with the survival structure of this fungus, the ergot

sclerotium A sclerotium (; : sclerotia () is a compact mass of hardened fungal mycelium containing food reserves. One role of sclerotia is to survive environmental extremes. In some higher fungi such as ergot, sclerotia become detached and remain dormant u ...

, can cause

ergotism Ergotism (pron. ) is the effect of long-term ergot poisoning, traditionally due to the ingestion of the alkaloids produced by the '' Claviceps purpurea'' fungus—from the Latin "club" or clavus "nail" and for "head", i.e. the purple club-h ...

in humans and other mammals. ''C. purpurea'' most commonly affects

outcrossing Out-crossing or out-breeding is the technique of crossing between different breeds. This is the practice of introducing distantly related genetic material into a breeding line, thereby increasing genetic diversity. Outcrossing in animals Out ...

species such as

(its most common host), as well as triticale,

wheat Wheat is a group of wild and crop domestication, domesticated Poaceae, grasses of the genus ''Triticum'' (). They are Agriculture, cultivated for their cereal grains, which are staple foods around the world. Well-known Taxonomy of wheat, whe ...

and

barley Barley (), a member of the grass family, is a major cereal grain grown in temperate climates globally. It was one of the first cultivated grains; it was domesticated in the Fertile Crescent around 9000 BC, giving it nonshattering spikele ...

. It affects oats only rarely.

Life cycle

An ''ergot kernel'' called ''Sclerotium clavus'' develops when a floret of flowering grass or cereal is infected by an

ascospore In fungi, an ascospore is the sexual spore formed inside an ascus—the sac-like cell that defines the division Ascomycota, the largest and most diverse Division (botany), division of fungi. After two parental cell nucleus, nuclei fuse, the ascu ...

of ''C. purpurea''. The infection process mimics a

pollen Pollen is a powdery substance produced by most types of flowers of seed plants for the purpose of sexual reproduction. It consists of pollen grains (highly reduced Gametophyte#Heterospory, microgametophytes), which produce male gametes (sperm ...

grain growing into an

ovary The ovary () is a gonad in the female reproductive system that produces ova; when released, an ovum travels through the fallopian tube/ oviduct into the uterus. There is an ovary on the left and the right side of the body. The ovaries are end ...

during

fertilization Fertilisation or fertilization (see American and British English spelling differences#-ise, -ize (-isation, -ization), spelling differences), also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give ...

. Because infection requires access of the fungal spore to the stigma, plants infected by ''C. purpurea'' are mainly

species with open flowers, such as rye ('' Secale cereale'') and Alopecurus. The proliferating fungal

mycelium Mycelium (: mycelia) is a root-like structure of a fungus consisting of a mass of branching, thread-like hyphae. Its normal form is that of branched, slender, entangled, anastomosing, hyaline threads. Fungal colonies composed of mycelium are fo ...

then destroys the plant ovary and connects with the

vascular bundle A vascular bundle is a part of the transport system in vascular plants. The transport itself happens in the stem, which exists in two forms: xylem and phloem. Both these tissues are present in a vascular bundle, which in addition will incl ...

originally intended for feeding the developing

seed In botany, a seed is a plant structure containing an embryo and stored nutrients in a protective coat called a ''testa''. More generally, the term "seed" means anything that can be Sowing, sown, which may include seed and husk or tuber. Seeds ...

. The first stage of ergot infection manifests itself as a white soft tissue (known as ''Sphacelia segetum'') producing sugary honeydew, which often drops out of the infected grass florets. This honeydew contains millions of asexual spores (

conidia A conidium ( ; : conidia), sometimes termed an asexual chlamydospore or chlamydoconidium (: chlamydoconidia), is an asexual, non- motile spore of a fungus. The word ''conidium'' comes from the Ancient Greek word for dust, ('). They are also ...

) which are dispersed to other florets by

insect Insects (from Latin ') are Hexapoda, hexapod invertebrates of the class (biology), class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (Insect morphology#Head, head, ...

s or rain. Later, the ''Sphacelia segetum'' convert into a hard dry ''Sclerotium clavus'' inside the husk of the floret. At this stage,

alkaloid Alkaloids are a broad class of natural product, naturally occurring organic compounds that contain at least one nitrogen atom. Some synthetic compounds of similar structure may also be termed alkaloids. Alkaloids are produced by a large varie ...

s and

lipid Lipids are a broad group of organic compounds which include fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E and K), monoglycerides, diglycerides, phospholipids, and others. The functions of lipids include storing ...

s (e.g.

ricinoleic acid Ricinoleic acid, formally called 12-hydroxy-9-''cis''-octadecenoic acid, is a fatty acid. It is an Unsaturated fatty acid, unsaturated omega-9 fatty acid and a hydroxy acid. It is a major component of the seed oil obtained from the seeds of casto ...

) accumulate in the Sclerotium. When a mature ''Sclerotium'' drops to the ground, the fungus remains dormant until proper conditions trigger its fruiting phase (onset of spring, rain period, need of fresh temperatures during winter, etc.). It germinates, forming one or several fruiting bodies with head and stipe, variously colored (resembling a tiny

mushroom A mushroom or toadstool is the fleshy, spore-bearing Sporocarp (fungi), fruiting body of a fungus, typically produced above ground on soil or another food source. ''Toadstool'' generally refers to a poisonous mushroom. The standard for the n ...

). In the head, threadlike sexual spores (ascospores) are formed in

perithecia An ascocarp, or ascoma (: ascomata), is the fruiting body ( sporocarp) of an ascomycete phylum fungus. It consists of very tightly interwoven hyphae and millions of embedded asci, each of which typically contains four to eight ascospores. Ascoc ...

, 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

. '' Polistes dorsalis'', a species of social wasps, have been recorded as a vector of the spread of this particular fungus. During their foraging behavior, particles of the fungal conidia get bound to parts of this wasp's body. As ''P. dorsalis'' travels from source to source, it leaves the fungal infection behind. Insects, including flies and moths, have also been shown to carry conidia of ''Claviceps'' species, but if insects play a role in spreading the fungus from infected to healthy plants is unknown.

Intraspecific variations

Early scientists have observed ''Claviceps purpurea'' on other

Poaceae Poaceae ( ), also called Gramineae ( ), is a large and nearly ubiquitous family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos, the grasses of natural grassland and species cultivate ...

as '' Secale cereale''. 1855, Grandclement described ergot on '' Triticum aestivum''. During more than a century scientists aimed to describe specialized species or specialized varieties inside the species ''Claviceps purpurea''. * ''Claviceps microcephala'' Tul. (1853) * ''Claviceps wilsonii'' Cooke (1884) Later scientists tried to determine host varieties as * ''Claviceps purpurea'' var. ''agropyri'' * ''Claviceps purpurea'' var. ''purpurea'' * ''Claviceps purpurea'' var. ''spartinae'' * ''Claviceps purpurea'' var. ''wilsonii''. Molecular biology has not confirmed this hypothesis but has distinguished three groups differing in their ecological specificity. * 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). Morphological criteria to distinguish different groups: The shape and the size of sclerotia are not good indicators because they strongly depend on the size and shape of the host floret. The size of conidia can be an indication but it is weak and it is necessary to pay attention to that, due to osmotic pressure, it varies significantly if the spores are observed in honeydew or in water. The sclerotial density can be used as the groups G2 and G3 float in water. The compound of alkaloids is also used to differentiate the strains.

Host range

Pooideae

'' Agrostis canina'', ''

Alopecurus myosuroides ''Alopecurus myosuroides'' is an Annual plant, annual Poaceae, grass, native to Eurasia, found in moist meadows, Deciduous, deciduous forests, and on cultivated and waste land. It is also known as slender meadow foxtail, black-grass, twitch grass ...

'' (G2), '' Alopecurus arundinaceus'' (G2), ''

Alopecurus pratensis ''Alopecurus pratensis'', known as the meadow foxtail or the field meadow foxtail, is a Perennial plant, perennial grass belonging to the grass family (Poaceae). It is native to Europe and Asia. This common plant is found on grasslands, especia ...

'', '' Bromus arvensis'', '' Bromus commutatus'', '' Bromus hordeaceus'' (G2), '' Bromus inermis'', '' Bromus marginatus'', '' Elymus tsukushiense'', ''

Festuca arundinacea ''Lolium arundinaceum'', commonly known as tall fescue, is a cool-season, perennial C3 grass species native to Europe and introduced to North America and other parts of the world. It naturally occurs in grasslands and coastal marshes.Texas Park ...

'', '' Elymus repens'' (G1), ''

Nardus stricta ''Nardus'' is a genus of plants belonging to the grass family, containing the single species ''Nardus stricta'', known as matgrass. It is placed in its own tribe Nardeae within the subfamily Pooideae. The name derives from ancient Greek ' () fro ...

'', '' Poa annua'' (G2), '' Phleum pratense'', ''

Phalaris arundinacea ''Phalaris arundinacea'', or reed canary grass, is a tall, perennial bunchgrass that commonly forms extensive single-species stands along the margins of lakes and streams and in wet open areas, with a wide distribution in Europe, Asia, northern ...

'' (G2), '' Poa pratensis'' (G1), ''

Stipa ''Stipa'' is a genus of 141 species of large Perennial plant, perennial hermaphrodite, hermaphroditic grasses collectively known as feather grass, needle grass, and spear grass. They are placed in the subfamily Pooideae and the tribe Stipeae, w ...

''.

Arundinoideae

'' Danthonia'', ''

Molinia caerulea ''Molinia caerulea'', known by the common name purple moor-grass, is a species of grass that is native to Europe, west Asia, and north Africa. It grows in locations from the lowlands up to in the Alps. Like most grasses, it grows best in acid s ...

''.

Chloridoideae

Spartina ''Spartina'' is a genus of plants in the grass family, frequently found in coastal salt marshes. Species in this genus are commonly known as cordgrass or cord-grass, and are native to the coasts of the Atlantic Ocean in western and southern Eu ...

'', '' Distichlis'' (G3)

Panicoideae

'' Setaria''

Epidemiology

''Claviceps purpurea'' has been known to humankind for a long time, and its appearance has been linked to extremely cold winters that were followed by rainy springs. The sclerotial stage of ''C. purpurea'' conspicuous on the heads of ryes and other such grains is known as ergot. Sclerotia germinate in spring after a period of low temperature. A temperature of 0-5 °C for at least 25 days is required. Water before the cold period is also necessary. Favorable temperatures for stroma production are in the range of 10-25 °C. Favorable temperatures for mycelial growth are in the range of 20-30 °C with an optimum at 25 °C. Sunlight has a chromogenic effect on the

with intense coloration.

Effects

The disease cycle of the ergot fungus was first described in 1853, but the connection with ergot and epidemics among people and animals was reported already in a scientific text in 1676. The ergot sclerotium contains high concentrations (up to 2% of dry mass) of the

ergotamine Ergotamine, sold under the brand name Ergomar among others, is an ergopeptine and part of the ergot family of alkaloids; it is structurally and biochemically closely related to ergoline. It is structurally similar to several neurotransmitter ...

, a complex molecule consisting of a tripeptide-derived cyclol-lactam ring connected via

amide In organic chemistry, an amide, also known as an organic amide or a carboxamide, is a chemical compound, compound with the general formula , where R, R', and R″ represent any group, typically organyl functional group, groups or hydrogen at ...

linkage to a lysergic acid (ergoline) moiety, and other alkaloids of the

ergoline Ergoline is a core structure in many alkaloids and their synthetic derivatives. Ergoline alkaloids were first characterized in ergot. Some of these are implicated in the condition of ergotism, which can take a convulsive form or a gangrenous for ...

group that are

biosynthesized Biosynthesis, i.e., chemical synthesis occurring in biological contexts, is a term most often referring to multi-step, enzyme- catalyzed processes where chemical substances absorbed as nutrients (or previously converted through biosynthesis) serve ...

by the fungus. Ergot alkaloids have a wide range of biological activities including effects on circulation and

neurotransmission Neurotransmission (Latin: ''transmissio'' "passage, crossing" from ''transmittere'' "send, let through") is the process by which signaling molecules called neurotransmitters are released by the axon terminal of a neuron (the presynaptic neuron ...

Ergotism Ergotism (pron. ) is the effect of long-term ergot poisoning, traditionally due to the ingestion of the alkaloids produced by the '' Claviceps purpurea'' fungus—from the Latin "club" or clavus "nail" and for "head", i.e. the purple club-h ...

is the name for sometimes severe pathological syndromes affecting humans or animals that have ingested ergot alkaloid-containing plant material, such as ergot-contaminated grains. Monks of the order of St.

Anthony the Great Anthony the Great (; ; ; ; – 17 January 356) was a Christian monk from Egypt, revered since his death as a saint. He is distinguished from other saints named Anthony, such as , by various epithets: , , , , , and . For his importance among t ...

specialized in treating ergotism victims with balms containing tranquilizing and circulation-stimulating plant extracts; they were also skilled in amputations. The common name for ergotism is "St. Anthony's Fire", in reference to monks who cared for victims as well as symptoms, such as severe burning sensations in the limbs. These are caused by effects of ergot alkaloids on the

vascular system In vertebrates, the circulatory system is a system of organs that includes the heart, blood vessels, and blood which is circulated throughout the body. It includes the cardiovascular system, or vascular system, that consists of the heart a ...

due to

vasoconstriction Vasoconstriction is the narrowing of the blood vessels resulting from contraction of the muscular wall of the vessels, in particular the large arteries and small arterioles. The process is the opposite of vasodilation, the widening of blood vesse ...

of blood vessels, sometimes leading to

gangrene Gangrene is a type of tissue death caused by a lack of blood supply. Symptoms may include a change in skin color to red or black, numbness, swelling, pain, skin breakdown, and coolness. The feet and hands are most commonly affected. If the ga ...

and loss of limbs due to severely restricted blood circulation. The neurotropic activities of the ergot alkaloids may also cause

hallucinations A hallucination is a perception in the absence of an external stimulus that has the compelling sense of reality. They are distinguishable from several related phenomena, such as dreaming ( REM sleep), which does not involve wakefulness; pse ...

and attendant irrational behaviour, convulsions, and even death. Other symptoms include strong uterine contractions,

nausea Nausea is a diffuse sensation of unease and discomfort, sometimes perceived as an urge to vomit. It can be a debilitating symptom if prolonged and has been described as placing discomfort on the chest, abdomen, or back of the throat. Over 30 d ...

seizure A seizure is a sudden, brief disruption of brain activity caused by abnormal, excessive, or synchronous neuronal firing. Depending on the regions of the brain involved, seizures can lead to changes in movement, sensation, behavior, awareness, o ...

s, and unconsciousness. Since the Middle Ages, controlled doses of ergot were used to induce

abortion Abortion is the early termination of a pregnancy by removal or expulsion of an embryo or fetus. Abortions that occur without intervention are known as miscarriages or "spontaneous abortions", and occur in roughly 30–40% of all pregnan ...

s and to stop maternal bleeding after childbirth.Untersuchungen über das Verhalten der Secalealkaloide bei der Herstellung von Mutterkornextrakten. Labib Farid Nuar. Universität Wien - 1946 - (University of Vienna) Ergot alkaloids are also used in products such as Cafergot (containing

caffeine Caffeine is a central nervous system (CNS) stimulant of the methylxanthine chemical classification, class and is the most commonly consumed Psychoactive drug, psychoactive substance globally. It is mainly used for its eugeroic (wakefulness pr ...

and

) to treat migraine headaches. Ergot extract is no longer used as a

pharmaceutical Medication (also called medicament, medicine, pharmaceutical drug, medicinal product, medicinal drug or simply drug) is a drug used to diagnose, cure, treat, or prevent disease. Drug therapy ( pharmacotherapy) is an important part of the ...

preparation. Ergot contains no

lysergic acid diethylamide Lysergic acid diethylamide, commonly known as LSD (from German ; often referred to as acid or lucy), is a Semisynthesis, semisynthetic, Hallucinogen, hallucinogenic compound derived from ergot, known for its powerful psychological effects and ...

(LSD) but rather ergotamine, which is used to synthesize lysergic acid, an analog of and precursor for synthesis of LSD. Moreover, ergot sclerotia naturally contain some amounts of lysergic acid.

Culture

Potato dextrose agar, wheat seeds or oat flour are suitable substrates for growth of the fungus in the laboratory. Agricultural production of Claviceps purpurea on rye is used to produce ergot alkaloids. Biological production of ergot alkaloids is also carried out by saprophytic cultivations.

Speculations

During the

Middle Ages In the history of Europe, the Middle Ages or medieval period lasted approximately from the 5th to the late 15th centuries, similarly to the post-classical period of global history. It began with the fall of the Western Roman Empire and ...

, human poisoning due to the consumption of rye bread made from ergot-infected grain was common in Europe. These epidemics were known as Saint Anthony's fire, or ''ignis sacer''. Gordon Wasson proposed that the psychedelic effects were the explanation behind the festival of

Demeter In ancient Greek religion and Greek mythology, mythology, Demeter (; Attic Greek, Attic: ''Dēmḗtēr'' ; Doric Greek, Doric: ''Dāmā́tēr'') is the Twelve Olympians, Olympian goddess of the harvest and agriculture, presiding over cro ...

at the

Eleusinian Mysteries The Eleusinian Mysteries () were initiations held every year for the Cult (religious practice), cult of Demeter and Persephone based at the Panhellenic Sanctuary of Eleusis in ancient Greece. They are considered the "most famous of the secret rel ...

, where the initiates drank kykeon''.'' Linnda R. Caporael posited in 1976 that the hysterical symptoms of young women that had spurred the

Salem witch trials The Salem witch trials were a series of hearings and prosecutions of people accused of witchcraft in Province of Massachusetts Bay, colonial Massachusetts between February 1692 and May 1693. More than 200 people were accused. Not everyone wh ...

had been the result of consuming ergot-tainted rye. However, her conclusions were later disputed by Nicholas P. Spanos and Jack Gottlieb, after a review of the historical and medical evidence. Other authors have likewise cast doubt on ergotism having been the cause of the Salem witch trials. The

Great Fear The Great Fear () was a general panic that took place between 22 July to 6 August 1789, at the start of the French Revolution. Rural unrest had been present in France since the worsening grain shortage of the spring. Fuelled by rumours ...

in France during the

Revolution In political science, a revolution (, 'a turn around') is a rapid, fundamental transformation of a society's class, state, ethnic or religious structures. According to sociologist Jack Goldstone, all revolutions contain "a common set of elements ...

has also been linked by some historians to the influence of ergot. British author John Grigsby claims that the presence of ergot in the stomachs of some of the so-called 'bog-bodies' (

Iron Age The Iron Age () is the final epoch of the three historical Metal Ages, after the Chalcolithic and Bronze Age. It has also been considered as the final age of the three-age division starting with prehistory (before recorded history) and progre ...

human remains from peat bogs N E Europe such as Tollund Man), reveals that ergot was once a ritual drink in a prehistoric fertility cult akin to the

cult of ancient

Greece Greece, officially the Hellenic Republic, is a country in Southeast Europe. Located on the southern tip of the Balkan peninsula, it shares land borders with Albania to the northwest, North Macedonia and Bulgaria to the north, and Turkey to th ...

. In his book ''Beowulf and Grendel'' he argues that the

Anglo-Saxon The Anglo-Saxons, in some contexts simply called Saxons or the English, were a Cultural identity, cultural group who spoke Old English and inhabited much of what is now England and south-eastern Scotland in the Early Middle Ages. They traced t ...

poem

Beowulf ''Beowulf'' (; ) is an Old English poetry, Old English poem, an Epic poetry, epic in the tradition of Germanic heroic legend consisting of 3,182 Alliterative verse, alliterative lines. It is one of the most important and List of translat ...

is based on a memory of the quelling of this fertility cult by followers of

Odin Odin (; from ) is a widely revered god in Norse mythology and Germanic paganism. Most surviving information on Odin comes from Norse mythology, but he figures prominently in the recorded history of Northern Europe. This includes the Roman Em ...

. He states that Beowulf, which he translates as ''barley-wolf'', suggests a connection to ergot which in German was known as the 'tooth of the wolf'. An outbreak of violent hallucinations among hundreds of residents of Pont St. Esprit in 1951 in the south of France has also been attributed to ergotism. Shortly after the event at least four people had been declared dead, although some claim the total number of deaths to be five or seven.

References

External links

Claviceps purpurea - Ergot Alkaloid

* ttp://content.nejm.org/cgi/content/short/356/1/29 New England Journal of Medicine - Dopamine Agonists and the Risk of Cardiac-Valve Regurgitation
Linnda Caporeal's article "Ergotism: The Satan Loosed in Salem?
{{Authority control Clavicipitaceae Food microbiology Fungi of Europe Psychoactive fungi Natural sources of lysergamides Medicinal fungi Parasitic fungi Fungal plant pathogens and diseases Cereal diseases Barley diseases Rye diseases Triticale diseases Wheat diseases Abortifacients Soma (drink) Fungi described in 1823 Taxa named by Elias Magnus Fries Fungus species