Ergot calls. Biologically active substances of ergot. Ergot cure for drug addiction

annually due to mass outbreaks ergot wheat in some regions, the yield decreases by 10-15%, and in unfavorable years, losses reach up to 25%. The decrease in wheat yield is proportional to the number of infected ears.

Germination of ergot sclerotia reduces the quality and quantity of the crop, affects the quality of flour and grain. On one ear there are from 1 to 5 sclerotia. The harm of developing ergot lies not only in reducing the amount of the crop. An admixture of wheat affected by ergot imparts poisonous properties to the flour.

Since 1995, ergot has been actively spreading in wheat and all grain crops, affecting winter crops the most.

The effect of ergot on the human body

Ergot causes a decrease in yield, but more significant is the presence of sclerotia in the grain. The harm of ergot to humans is that its sclerotia contain toxic alkaloids (ergotamine, ergotoxin, ergometrine, ergin, etc.) - organic matter produced by cereals, horsetails, ferns and mushrooms.

They are dangerous for warm-blooded organisms and cause constriction of blood vessels. Many of them - strong poisons causing serious poisoning. The disease is associated with damage to the central nervous system and has the following symptoms:

• muscle cramps;
• weakness, dizziness, loss of consciousness;
• gastrointestinal disorders;
• delirium, anxiety, bouts of fear;
• change in perception as a result of damage to brain tissue;
• mental disorders (hallucinations).

In the old days, the disease that appeared due to the use of bread from this infected flour was called "evil writhing."

Alkaloids contained in sclerotia can cause miscarriages. Contaminated grain in an amount of more than 0.1% is not suitable for the production of feed or ethanol, because. poisonous to animals and humans. An admixture of sclerotia in flour of more than 0.05% makes it dangerous for living beings.

Ergot alkaloids are not destroyed by heat treatment. Ergot poisoning is characterized by a high degree of lethality (a dosage of 5 g is lethal), but it all depends on the health and endurance of the body, age, body weight and gender of the person.

Application in medicine

In small doses, the substance is medicine, since the horns contain ergotamine and ergometrine - hemostatic and obstetric agents. The alkaloids vincristine and vinblastine are used in medicine as antitumor agents.

Ergot alkaloids are widely used in gynecology as a means of stimulating uterine contraction, which has a vasoconstrictive effect. Natural ergot alkaloids and their synthetic analogues are used in medical abortion, etc.

Until the 60s. In the 20th century, sclerotia were collected on infected ears, and then artificially bred in special agriculture. In the 21st century, alkaloids are obtained as a result of fermentation, growing sclerotia of the fungus in an artificial nutrient medium.

Development of the disease

The causative agents of the disease are purple ergot fungi (Claviceps purpurea). Common name disease caused by fungi of the genus Claviceps is called ergot. It affects about 400 species of plants from the cereal family (Poaceae).

Ergot is a disease of crops. The crops of winter rye are mainly affected, less often - wheat and triticale. It is a sporadic form of ergot that overwinters in the ground as conidia that germinate in spring. Sources of infection: earth with sclerotia, wind, insects. Infection of cereals with ergot occurs through the spread of azigotes by wind and insects during the flowering period. Only fully opened flowers become infected. The source of primary infection is conidia (exogenous spores of asexual sporulation).

Plantations where pre-sowing treatment has not been carried out or seeds of unknown origin have been sown are vulnerable to infection. The occurrence of the disease is observed on self-seeding, from which azigotes can be carried by wind to cultivated fields.

It is worth knowing that the life span of a wintering fungus (ergot purpurea) is 3 years.

In spring, the spores germinate as filamentous stems ending in a red-brown swelling (spherical stroma heads). Numerous ascospores are formed in the stroma (in the ascus - a bag), which ripen during flowering. They are spread by the wind and infect young stems. flowering plants. Conidia of the fungus develop on the affected stems. On healthy plants, conidia are carried by insects that are attracted to sweet secretions, which promotes the spread of ergot. By the time the grain ripens, the infected ovary turns into a sclerotium.

The development of disease and infection is favored by wet and rainy weather. Temperatures +10-+14°С and relative humidity more than 70% - an ideal environment for the development of ergot cereals. Gonidia germinate in spring, forming fruiting bodies. The intensive development of the disease is also facilitated by numerous precipitations in the flowering stage of cereal crops.

Symptoms of infection

• Claviceps purpurea - completed stage;
• Sphacelia segetum - conidial stage.

The uterine horns are white inside, their size depends on the plant variety and the number of infected ears. Some of the horns fall out of the ears during the harvest, the rest remain on them.

Ergot Control Methods

When laying the seed material for storage, one must be careful, checking it for the presence of ergot, as it contributes to the infection of the grain. When choosing a wheat variety, one should take into account its adaptation to climatic conditions prevailing in the field of cultivation. It is recommended to choose varieties for planting with the highest degree infection resistance.

The surface of the soil for the destruction of conidia is plowed (peeling 5-7 cm, disking 10-12 cm), deep autumn plowing is carried out (20 cm).

Ergot control methods are:

• sowing grains without sclerotia;
• selection of suitable, resistant varieties that are less susceptible to infection;
• careful selection of seed material;
• grain cleaning and timely sowing;
• correct and thorough agrotechnical operations (deep plowing);
• balanced nitrogen fertilizer;
• plant rotation;
• destruction of self-seeding and weeds;
• correct crop rotation (break 3-4 years) and the optimal amount of grain per m2;
• the use of fungicides.

Conidia on healthy plants germinate quickly and infect the ear. In spring, in order to reduce the spread of the fungus, it is recommended to get rid (mow) of the roadside from wild-growing cereals up to 800-1000 m. up to 50%), located at a depth of 1-2 cm or on the surface.

Complex protection methods

Since January 2014, a comprehensive protection of winter wheat has been applied. The basis is the optimal use of the natural properties of the fields and cultivated varieties, using a safe and appropriate amount of fertilizer and chemicals for plant protection.

Rational tillage should provide optimal soil structure and density, increase its biological activity, promote water accumulation and reduce the number of weeds and azigots, creating conditions for fast and uniform shoots.

Integrated protection programs first use non-chemical farming practices. The next step is chemical treatments to reduce pathogens that threaten the wheat crop. When non-chemical methods do not allow keeping the disease below the threshold of harmfulness, chemicals are used.

Ergot harm

To suppress the development of the conidial stage and protect cereals at the heading stage, Belarusian researchers recommend fungicidal treatments with tillt 500 ml/ha; folicur 1000 ml/ha and alto-super 400 ml/ha. Treatment during flowering by sowing with these preparations reduced ergot damage by 32-50%.

High humidity in the plantation, associated with dense sowing, promotes the development of an infection responsible for the disease of wheat ears, stems and leaves.

Optimal fit does not allow the mass development of pathogens. Appropriate isolation of winter wheat crops from spring wheat is one way to avoid ergot infestation and improve grain quality.

The appearance of ergot on cereals is observed more often in wet summers when sowing seeds that are poorly cleaned of horns. Horns, falling on the ground during sowing or crumbling to the ground after ripening, are easily transferred under the snow winter period and in the spring, when they germinate, they infect the blooming rye with their inconspicuous thread-like spores.

Ergot fungus horns are highly poisonous. Getting in the form of an impurity in a significant amount in flour, ergot causes serious diseases in humans known as "evil writhing". An admixture of fresh ergot to the flour in the amount of 0.05-0.1% makes the flour unfit for consumption.

Animals that eat rye with ergot are also severely poisoned; they get necrosis of the ears, tail and legs. Therefore, it is necessary to carefully clean the grain from the horns with sorting machines, sieves or screens.

Application and collection of ergot.

IN medical business ergot horns are used, giving generally recognized medications(decoction, tincture, liquid and thick extract, powders) that cause vasoconstriction and increase blood pressure, A strong abortifacient ("uterine horns").

Ergot is harvested during the ripening of rye: directly in the field or separated after threshing the grain. When harvested by hand, the purest product is obtained. Selected ergot should be immediately dried in a shaded, well-ventilated room, at a temperature not exceeding 50 °, scattering the horns in a thin layer on cloth or paper. Drying is finished only when the horns, when bent, will break, making a dry crack.

The finished raw material should consist of horns having a white or light color in the break. yellow and a narrow purple border around the edges. Humidity should not exceed 11% (horns break with a bang). The smell is weak, mushroom.

The taste is oily, unpleasant (poisonous!). No more than 5% of yellow and brownish horns are allowed, broken and crushed - no more than foreign impurities - no more than 3% and mineral impurities - no more than 1%. Since during storage the horns lose their medicinal properties, it is required annually in pharmacies to replace the remaining material with fresh material in the fall.

Ergot photo.

The core of ergot, called sclerotium, develops when fungal spores infect a plant flower or cereal. They mimic the mechanism of a pollen grain by growing into the cavity with the ovary during pollination. During infection, the fungal spores are required to have access to the stigma; ergot-infected plants are mostly crossbreeds such as rye (Secalecereale) and chaff (genus Lolium). The spread of the mycelium of the fungus destroys the ovary of plants, connects with the vascular bundle, designed to deliver nutrients to the seeds. The first stage of infection is as follows - white soft tissue (sphacelia), which produces a sweet liquid dripping from the inflorescences. This liquid contains thousands of asexual spores (conidia), which insects transfer to other inflorescences. The sphalecia then transforms into a dry, hard sclerotia inside the inflorescence sheath. At this stage, alkaloids and lipids accumulate in the sclerotium. Ergot species from tropical and subtropical regions produce macro- and microconidia in a sticky liquid. Macroconidia vary in shape and size, while microconidia are universal, ranging from oval to spherical (5×3µm). Macroconidia are capable of producing secondary conidia. The germ tube emerges from the macroconidia through the surface, forming oval or pear-shaped secondary conidia into which the contents of the macroconidia move. The secondary conidia form a white, snow-like surface on droplets of a sticky liquid that spreads with the wind. This process is not observed with the participation of the species Claviceps purpurea, Claviceps grohii, Claviceps nigricans and Claviceps zizaniae, all species grow in the northern temperate regions. When a mature sclerotium falls to the ground, the fungus remains dormant until certain conditions (such as the arrival of spring or a rainy season) trigger its fruiting phase. It germinates, forming one or more fruit bodies with heads and legs different color(reminiscent of small mushrooms). In the head, filamentous spores of sexual reproduction are formed, which are released during the flowering period of the host plant. Ergot causes a decrease in the yield and quality of grain and hay, if cattle eat infected grain or hay, a disease called ergotism can develop. The black protruding sclerotia of C. purpurea is well known. But many tropical species ergots have brown or greyish sclerotia that are shaped like the seeds of the host plant. For this reason, the infection is difficult to detect immediately. Insects, including flies and midges, carry conidia of the Claviceps species, but it is not known whether insects are directly involved in the transfer of the fungus from infected plants to healthy ones.

Effects on humans and other mammals

Ergot contains a high concentration (up to 2% dry weight) of the alkaloid ergatomine, a complex molecule consisting of a tripeptide-derived cyclol-lactam ring linked to lysergic acid residues (ergoline) via an amide bond, as well as other alkaloids of the ergoline group, which are biosynthesized by the fungus. Ergot alkaloids have a wide range of biological activities, including effects on circulation and neurotransmission. Ergot alkaloids can be classified into two groups: 1. Derivatives of 6,8-dimethylergoline and 2. Derivatives of lezyrgic acids. Ergotism is the name given to a pathological syndrome that affects humans and other mammals when they ingest substances containing ergot alkaloids, such as ergot-infected cereal grains. St. Anthony's Hospital, a monastic order founded in 1095, treats those affected by ergotism with a balm containing plant extracts that have calming and circulatory effects. Another name for ergotism is “the fire of St. Anthony”, it reflects the attitude towards the monastic order and the burning sensation in the limbs, one of the symptoms of the disease. This sensation is caused by the effect on the vascular system of ergot alkaloids, which can also lead to gangrene and loss of limbs due to limited circulation. The neurotropic effects of ergot alkaloids can also cause hallucinations and associated irrational behavior, as well as convulsions and even death. Other symptoms include severe uterine contractions, nausea, convulsions, and loss of consciousness. Since the Middle Ages, controlled doses of ergot have been used to induce abortion and to stop bleeding after childbirth. Ergot extract is used for pharmaceutical preparations, for example, ergot alkaloids are used in caergot (contains caffeine and ergotamine or ergoline), a medicine for migraine and headaches, and ergometrine, a drug that causes uterine contractions to control bleeding after childbirth. In addition to the alkaloids, ergot also produces tremorgens (paspalitrems), which cause a fever in livestock. Fungi genus Penicillium and Aspergillus also produce ergot alkaloids, in particular some strains of the human pathogen Aspergillus sfumigatus, and they have also been isolated from plants in the bindweed family, prominent representative which is bindweed purple. Ergot contains lysergic acid dimethylamide (LSD) and a precursor, ergotamine. Lysergic acid is an analogue and precursor of LSD synthesis. The New England Journal of Medicine published a paper on January 4, 2007 describing a UK study of over 11,000 patients with Parkinson's disease. The study noted that two ergot-based drugs, Pergolide and Cabergoline, used to treat Parkinson's disease, can increase the risk of leaky heart valves by up to 700%.

History

Poisoning due to eating rye bread made from ergot-infected grains was common in Europe during the Middle Ages. The epidemic was called the "Fire of St. Anthony", or "Holy Fire". Some historical events, such as the "Great Fear" in France during the French Revolution, are associated with poisoning. Linda Caporel published an article in 1976 saying that the hysterical symptoms of young women that caused the case Salem witches, are the result of eating rye contaminated with ergot. However, after reviewing the medical and historical evidence, Nicholas Spanos and Jack Gottlieb disputed her findings. Other study authors also question whether ergot is the cause of the Salem witchcraft. For centuries, obstetricians and physicians have used ergot extract to speed up labor and induce abortion. Studies have shown that prophylactic use of uterotonics in the third stage of labor reduces postpartum blood loss. In 1808 John Stearns learned from a German midwife new way accelerate childbirth. Ergot, a powerful natural drug that stimulates the muscles of the uterus when taken orally, turned out to be the way. It causes incessant contractions. Stearns stressed the importance of ergot, which saves doctors time and helps women get through childbirth more easily. Prior to the use of anesthesia, there was no antidote or way to control the properties of ergot. Therefore, if the fetus did not move as expected, the drug could cause uterine rupture and death of the fetus. Fortunately, doctors have realized that using ergot without an antidote can be very dangerous. They limited his use of the drug to only stop bleeding and remove the placenta. In the 1930s, a variety of abortifacients for women were sold by various companies, such as Molex Pills and Cote Pills. Birth control devices and abortion pills were banned from the market, so they were offered to women with a "delay". The recommended dosage was seven ergot grains per day. According to the FTC, the pills included ergotine, aloe, black hellebore and other substances. The efficacy and safety of these tablets is unknown. The FTC considered them unsafe and ineffective, so it ordered them to stop selling them. The American writer John Grigsby argues that the presence of ergot in the stomachs of the so-called "bog bodies" (the remains of people of the Iron Age in the swamps of Europe, a man from Tollund) speaks of their use in ritual drinks of a fertility cult similar to the cult of the Eleusinian mysteries in Ancient Greece. He argues that the Anglo-Saxon poem "Beowulf" is based on the memory of the suppression of the fertility cult by the followers of Odin. John Grigsby writes that there is a connection between Beowulf, which he calls barley-wolf (barley wolf) and ergot, which is known in German as "wolf's tooth", there is a connection. An alternative interpretation of Beowulf is "bee-wolf" (wolf bee). The hallucinogenicity of kykeon, a drink used by members of the Greek cult of the Eleusinian mysteries, may come from ergot. LSD, a powerful hallucinogen, was first synthesized from ergot alkaloids by the Swiss chemist Albert Hofmann in 1938.

Claviceps purpurea

Mankind has known about the ergot species Claviceps purpurea since ancient times, its appearance was associated with cold winters after rainy summers. Favorable temperature for growth is 18–30 °C. Temperatures above 37 °C lead to rapid germination of conidia. sunlight produces a chromogenic effect on the mycelium, giving an intense color. Grain mashes and germinated rye are suitable substrates for milking ergot growth in the laboratory.

Claviceps africana

Claviceps africana infects sorghum and was first identified in Texas in 1997. It only infects unfertilized ovaries, so self-pollination and fertilization can reduce infection, but male-sterile lines are particularly susceptible to infection. Symptoms of C. africana infection include the secretion of a gooey fluid (fluid high in sugar and conidia) that attracts insects such as flies, beetles, and wasps. This, in turn, promotes the spread of the fungus to uninfected plants. C. africana caused an ergot infection that created a famine in 1903-1906 in the Northern region of Cameroon, in western Africa, and in eastern and southern Africa (especially Zimbabwe) and in South Africa. Male sterile sorghum is particularly susceptible to infection, first reported in the 1960s. Infections most often spread at cold night temperatures, below 12°C, 2-3 weeks before flowering.

It is most often found on rye, and in areas with high moisture during the flowering period, it appears on wheat and barley. Sclerotia (ergot horns) contain various alkaloids that can cause poisoning in humans and animals.

After the flowering of cereals of the affected grains, sclerotia are formed, which protrude on the ear. Depending on the type of cereal, the size of the ergot sclerotia varies from a few millimeters to 4 cm (for rye).

The causative agent of the infection is a fungus Claviceps purpurea belonging to the class Ascomycetes. Ergot persists through the winter in the soil and spreads along with the seeds. During flowering, sclerotia germinate and form perithecia, in which ascospores are formed. They infect flowering crops. Mycelium is formed in the ovary, and insects help spread the conidia to other flowers. The mycelium then acquires the shape of a horn and subsequently retains its viability for one year. In exceptional cases, they may overwinter twice.

Protective Measures

Seed material cleaning, deep autumn plowing. The development of the disease is facilitated by minimal tillage technologies and sowing with uncleaned seed material.

3. Black leg of cabbage. Protection measures.

black leg- a dangerous disease of seedlings of cabbage, seedlings of other crops. A characteristic sign of the disease is the darkening and decay of the lower part of the stem.

With early damage, when seedlings have only cotyledon leaves, the affected part of the stem becomes watery, and then turns brown and rots. This leads to the death of the plant. The disease is quickly transmitted from a diseased plant to neighboring ones.

With a later infection of seedlings, almost ready for planting in the ground, the diseased part of the stem dries up, the root collar becomes thinner and darker - a constriction is formed. Such seedlings do not die, but lag behind in growth, the roots develop poorly, and when transplanted, the plants do not take root well.

pathogens - different kinds mushrooms ( Pyhtium debaryanum Hesse, Olpidium brassicae Wor., Phizoctonia aderholdii Kolosh., mushrooms of the genus Fusarium sp.), which remain in the soil and in plant residues, especially with long-term continuous use of greenhouses and hotbeds for cabbage seedlings.

The development of pathogens of the black leg is promoted by high humidity and increased acidity of the soil. Thickened seedling crops are susceptible to disease, especially with excessive application of nitrogen fertilizers. The cause of the spread of the disease can be poor ventilation, abundant watering and sudden changes in temperature.

Control measures

Cultivation of varieties of cabbage resistant to black leg. The varieties most affected by the black leg are Moscow late 9, Amager 611, Belarusian 455. The variety is resistant Cossack and some other varieties.

Before sowing, the seeds are disinfected with biological preparations (Baktofit, Planriz, Fitosporin, Fitolavin-300) or more effective chemical ones (Fundazol, Cumulus DF, TMTD). Such dressing is necessary to destroy pathogens on seeds. But pathogens can also be in the soil. Therefore, for growing seedlings, you need to use fresh soil, if possible, replacing it annually. If replacement is not possible, then the soil must be disinfected.

Soil disinfection can be carried out in various ways. In the sowing boxes, the soil is spilled twice with boiling water or a 1% solution of potassium permanganate. In greenhouses, it is recommended to disinfect the soil with freshly slaked lime (1-1.5 kg / m 2). A more modern biological remedy is spilling the soil with Fitosporin solution. Three days before sowing seeds or before picking seedlings, Cumulus DF (5 g / m 2) can be applied to the soil.

When foci of the disease appear, the affected plants are carefully removed, the seedlings are watered with a pink solution of potassium permanganate (3-5 g per 10 liters of water), then the seedlings are not watered at all for a week.

For prevention and at the first signs of the disease, seedlings are recommended to be sprayed with biological preparations (Bactofit, Planriz, Fitosporin, Fitolavin-300).

Ticket number 30

1. Basidiomycetes. Features of the structure and development.

Grain diseases

Grain of spiked crops can be exposed to various diseases.

There are mainly two forms of smut infestation in cereals: hard smut, sometimes called wet or stinky smut, and loose smut.

Solid smut, getting into the grain mass during harvesting, sharply worsens the quality of food grain.

Infection of wheat occurs by spores that enter the grain during milling. In the soil, the spores germinate, the sprout of the fungus penetrates the sprout of wheat, reaches the point of growth and develops along with the wheat, spreading along the stem. Later, the mycelium of the fungus penetrates into the ear, into the resulting spikelets and ovaries. As a result of such a defeat in the ear, instead of grain, bags are usually obtained. large sizes and rounder than normal grains. These smut sacs are filled with a black smearing mass, consisting of a huge number of spores. The spores have an unpleasant herring odor due to the presence of trimethylamine. When harvesting and threshing wheat affected by hard smut, the smut sacs are destroyed and the spilled spores stick to healthy grains. In wheat, grains, the tips of which are smeared with black spores of a hard (stinking) smut, are called maran or blue-headed. Flour obtained from such grain has an unpleasant blue color and retains a herring smell. The fight against hard smut is carried out by dressing the seed grain with various poisons.

Loose smut significantly reduces crop yields by infecting wheat. Infection occurs during flowering by means of spores that are easily scattered in the wind and fall on the stigmas of flowers.

In appearance, the grain infected with loose smut cannot be distinguished, although it sometimes acquires a slightly wrinkled surface with a matte tint. Inside the grain is a mycelium. Sometimes there is a palpable grain. Loose smut also leads to hidden losses, which are manifested in a decrease in field similarity of seeds (from 4 to 22%), an increase in susceptibility to leaf rust up to 15%, to stem rust up to 10-30%, to powdery mildew up to 10-15%. Seed grain suspected of being affected by loose smut must be dressed.

Ergot

A disease of cereal crops caused by a parasitic fungus belonging to marsupial fungi. Ergot develops in the ovaries of plants. Horns (sclerotia) 1-4 cm long are formed in the ear of grains, dark purple on the outside and white in the nutria. Ergot reproduces by spores carried (during the flowering period of cereals) by wind and insects. Rainy weather favors ergot development. The affected ear differs from the normal one in appearance in that it is covered with a sticky, sweetish liquid, the so-called honeydew, secreted by the fungus to the surface in the form of small droplets. Appearance the affected ovary changes after 15-20 days: it turns into a dense horn; during harvesting and threshing, the horns get into the grain and clog it. Food and fodder grain during acceptance and release are carefully controlled for ergot content.