Cyathus stercoreus
Encyclopedia
Cyathus stercoreus, commonly known as the dung-loving bird's nest, is a species of fungus in the genus Cyathus
Cyathus
Cyathus is a genus of fungi in the Nidulariaceae, a family collectively known as the bird's nest fungi. They are given this name since they resemble tiny bird's nests filled with "eggs", structures large enough to have been mistaken in the past for seeds. However, these are now known to be...

, family Nidulariaceae
Nidulariaceae
The Nidulariaceae are a family of fungi in the order Nidulariales. Commonly known as the bird's nest fungi, their fruiting bodies resemble tiny egg-filled birds' nests...

. Like other species in the Nidulariaceae, the fruiting bodies of C. stercoreus resemble tiny bird's nests filled with eggs. The fruiting bodies are referred to as splash cups, because they are designed to use the force of falling drops of water to dislodge and disperse their spores. The species has a worldwide distribution, and prefers growing on dung, or soil containing dung; the specific epithet is derived from the Latin word stercorarius, meaning "of dung".

Description

The fruiting bodies, or perida
Peridium
The peridium is the protective layer that encloses a mass of spores in fungi. This outer covering is a distinctive feature of the Gasteromycetes.-Description:...

, are funnel- or barrel-shaped, 6–15 mm tall, 4–8 mm wide at the mouth, sometimes short-stalked, golden brown to blackish brown in age. The outside wall of the peridium, the ectoperidium, is covered with tufts of fungal hypha
Hypha
A hypha is a long, branching filamentous structure of a fungus, and also of unrelated Actinobacteria. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium; yeasts are unicellular fungi that do not grow as hyphae.-Structure:A hypha consists of one or...

e that resembles shaggy, untidy hair. However, in older specimens this outer layer of hair (technically a tomentum) may be completely worn off. The internal wall of the cup, the endoperidium, is smooth and grey to bluish-black. The 'eggs' of the bird's nest – the peridioles – are blackish, 1–2 mm in diameter, and there are typically about 20 in the cup. Peridioles are often attached to the fruiting body by a funiculus
Funiculus
The cerebrospinal fibers consist of numerous nerve fibers collected together and enclosed in membranous sheaths. A small bundle of fibers, enclosed in a tubular sheath, is called a funiculus; if the nerve is of small size, it may consist only of a single funiculus; but if large, the funiculi are...

, a structure of hypha
Hypha
A hypha is a long, branching filamentous structure of a fungus, and also of unrelated Actinobacteria. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium; yeasts are unicellular fungi that do not grow as hyphae.-Structure:A hypha consists of one or...

e that is differentiated into three regions: the basal piece, which attaches it to the inner wall of the peridium, the middle piece, and an upper sheath, called the purse, connected to the lower surface of the peridiole. In the purse and middle piece is a coiled thread of interwoven hyphae called the funicular cord, attached at one end to the peridiole and at the other end to an entangled mass of hyphae called the hapteron. However, Brodie reports that sometimes C. stercoreus is found without a funiculus, which has led some authors to misidentify this species with the genus Nidula
Nidula
Nidula is a genus of fungi in the family Nidulariaceae. Like other members of the Nidulariaceae, their fruit bodies resemble tiny egg-filled birds' nests, from which they derive their common name "bird's nest fungi"...

.
The spore
Spore
In biology, a spore is a reproductive structure that is adapted for dispersal and surviving for extended periods of time in unfavorable conditions. Spores form part of the life cycles of many bacteria, plants, algae, fungi and some protozoa. According to scientist Dr...

s of C. stercoreus are roughly spherical and relatively large, with typical dimensions of 20–35 x 20–25 µm
Micrometre
A micrometer , is by definition 1×10-6 of a meter .In plain English, it means one-millionth of a meter . Its unit symbol in the International System of Units is μm...

, although great variability in spore size has been noted. The spores are sessile
Sessility (botany)
In botany, sessility is a characteristic of plants whose flowers or leaves are borne directly from the stem or peduncle, and thus lack a petiole or pedicel...

 (growing directly from the surface of the basidium, without attachment via a sterigmata), and are separated from the basidia after it collapses and gelatinizes. This is accompanied by the gelatinization of the inner walls of the peridiole.

Ultrastructure

Examination of fruiting bodies using scanning electron microscopy and transmission electron microscopy
Transmission electron microscopy
Transmission electron microscopy is a microscopy technique whereby a beam of electrons is transmitted through an ultra thin specimen, interacting with the specimen as it passes through...

 has revealed details about their ultrastructure—their microscopic architecture and arrangement. For example, the hyphae of the hapteron form a dense tangled network, while the hyphae of the funicular cord are arranged in a twisted form like a rope. Further, the funicular cord, known to be highly elastic and with a high tensile strength
Tensile strength
Ultimate tensile strength , often shortened to tensile strength or ultimate strength, is the maximum stress that a material can withstand while being stretched or pulled before necking, which is when the specimen's cross-section starts to significantly contract...

, is made of thicker hyphae than the rest of the funiculus. Also, the ecto- and endoperidium are made of thick-walled, unbranched hyphae, known as skeletal hyphae. It has been proposed that these skeletal hyphae form a structural network that helps the fruiting body maintain the elasticity vital for proper functioning of the spore dispersal mechanism.

Life cycle

The life cycle of Cyathus stercoreus, which contains both haploid and diploid stages, is typical of taxa in the basidiomycetes that can reproduce both asexually (via vegetative
Vegetative reproduction
Vegetative reproduction is a form of asexual reproduction in plants. It is a process by which new individuals arise without production of seeds or spores...

 spores), or sexually (with meiosis
Meiosis
Meiosis is a special type of cell division necessary for sexual reproduction. The cells produced by meiosis are gametes or spores. The animals' gametes are called sperm and egg cells....

). Basidiospore
Basidiospore
A basidiospore is a reproductive spore produced by Basidiomycete fungi. Basidiospores typically each contain one haploid nucleus that is the product of meiosis, and they are produced by specialized fungal cells called basidia. In grills under a cap of one common species in the phylum of...

s produced in the peridioles each contain a single haploid nucleus. After dispersal, the spores germinate and grow into homokaryotic
Homokaryotic
Homokaryotic refers to multinucleate cells where all nuclei are genetically identical. It is the antonym of heterokaryotic....

 hyphae, with a single nucleus in each compartment. When two homokaryotic hypha
Hypha
A hypha is a long, branching filamentous structure of a fungus, and also of unrelated Actinobacteria. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium; yeasts are unicellular fungi that do not grow as hyphae.-Structure:A hypha consists of one or...

e of different mating compatibility groups
Mating type
Mating types occur in eukaryotes that undergo sexual reproduction via isogamy. Since the gametes of different mating types look alike, they are often referred to by numbers, letters, or simply "+" and "-" instead of "male" and "female." Mating can only take place between different mating...

 fuse with one another, they form a dikaryotic
Dikaryon
Dikaryon is from Greek, di meaning 2 and karyon meaning nut, referring to the cell nucleus.The dikaryon is a nuclear feature which is unique to some fungi, in which after plasmogamy the two compatible nuclei of two cells pair off and cohabit without karyogamy within the cells of the hyphae,...

 (containing two nuclei) mycelia in a process called plasmogamy
Plasmogamy
Plasmogamy is a stage in the sexual reproduction of fungi. In this stage, the cytoplasm of two parent mycelia fuse together without the fusion of nuclei, as occurs in higher terrestrial fungi. After plasmogamy occurs, the secondary mycelium forms. The secondary mycelium consists of dikaryotic...

. After a period of time (approximately 40 days when grown from pure culture in the laboratory) and under the appropriate environmental conditions, fruiting bodies may be formed from the dikaryotic mycelia. These fruiting bodies produce peridioles containing the basidia upon which new basidiospores are made. Young basidia contain a pair of haploid sexually compatible nuclei which fuse, and the resulting diploid fusion nucleus undergoes meiosis to produce haploid basidiospores.

Development

Extreme variability in fruiting body form and color has been noted for C. stercoreus. Brodie reported discovering a slender-stemmed "twinned" form, with two fruiting bodies originating from the same stalk. As has been shown in laboratory-grown specimens, the development and form of the fruiting bodies is at least partially dependent on the intensity of light it receives during development. For example, exposure of the heterokaryotic
Heterokaryotic
Heterokaryotic refers to cells where two or more genetically different nuclei share one common cytoplasm. It is the antonym of homokaryotic. This stage after Plasmogamy, the fusion of the cytoplasm,a and before Karyogamy, the fusion of the nuclei. It is neither 1n or 2n. It is in the sexual...

 mycelium
Mycelium
thumb|right|Fungal myceliaMycelium is the vegetative part of a fungus, consisting of a mass of branching, thread-like hyphae. The mass of hyphae is sometimes called shiro, especially within the fairy ring fungi. Fungal colonies composed of mycelia are found in soil and on or within many other...

 to light is required for fruiting to occur, and furthermore, this light needs to be at a wavelength
Wavelength
In physics, the wavelength of a sinusoidal wave is the spatial period of the wave—the distance over which the wave's shape repeats.It is usually determined by considering the distance between consecutive corresponding points of the same phase, such as crests, troughs, or zero crossings, and is a...

 of less than 530 nm. Lu suggests that certain growing conditions – such as a shortage in available nutrients – shifts the fungus' metabolism
Metabolism
Metabolism is the set of chemical reactions that happen in the cells of living organisms to sustain life. These processes allow organisms to grow and reproduce, maintain their structures, and respond to their environments. Metabolism is usually divided into two categories...

 to produce a hypothetical "photoreceptive precursor" that enables the growth of the fruiting bodies to be stimulated and affected by light. The fungi is also positively phototrophic
Phototropism
Phototropism is directional growth in which the direction of growth is determined by the direction of the light source. In other words, it is the growth and response to a light stimulus. Phototropism is most often observed in plants, but can also occur in other organisms such as fungi...

, that is, it will orient its fruiting bodies in the direction of the light source.

Habitat and distribution

Being coprophilous
Coprophilous fungi
Coprophilous fungi are a type of saprobic fungi that grow on animal dung. The hardy spores of coprophilous species are unwittingly consumed by herbivores from vegetation, and are excreted along with the plant matter...

, C. stercoreus grows on dung
Feces
Feces, faeces, or fæces is a waste product from an animal's digestive tract expelled through the anus or cloaca during defecation.-Etymology:...

, in soil with dung, and bonfire sites; it has also been recorded growing on sand dunes. The fungus is known to have a worldwide distribution, and Curtis Gates Lloyd
Curtis Gates Lloyd
Curtis Gates Lloyd was an American mycologist known for both his research on the Gasteromycetes, as well as his controversial views on naming conventions in taxonomy. He had a herbarium with over 59,000 fungal specimens, and published over a thousand new species of fungi...

, in his monograph on the Nidulariaceae, wrote that it "probably occurs in every country where manure occurs."

Spore dispersal

When a drop of water hits the interior of the cup at the appropriate angle and velocity, the peridioles are ejected into the air by the force of the drop. The force of ejection tears open the purse, and results in the expansion of the funicular cord, formerly coiled under pressure in the lower part of the purse. The peridioles, followed by the highly adhesive funicular cord and basal hapteron, may hit a nearby plant stem or stick. The hapteron sticks to it, and the funicular cord wraps around the stem or stick powered by the force of the still-moving peridiole. After drying out, the peridiole remains attached to the vegetation, where it may be eaten by a grazing herbivorous animal, and later deposited in that animal's dung to continue the life cycle.

Bioactive compounds

A number of polyketide
Polyketide
Polyketides are secondary metabolites from bacteria, fungi, plants, and animals. Polyketides are usually biosynthesized through the decarboxylative condensation of malonyl-CoA derived extender units in a similar process to fatty acid synthesis...

-type antioxidative compounds, cyathusals A, B, and C, and pulvinatal have been isolated and identified from the liquid culture of Cyathus stercoreus. Furthermore, the polyketides known as cyathuscavin A, B, and C (isolated from liquid culture) also have antioxidant activity, and have DNA
DNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...

 protection activity.

Traditional medicine

In Traditional Chinese medicine
Traditional Chinese medicine
Traditional Chinese Medicine refers to a broad range of medicine practices sharing common theoretical concepts which have been developed in China and are based on a tradition of more than 2,000 years, including various forms of herbal medicine, acupuncture, massage , exercise , and dietary therapy...

, a decoction
Decoction
Decoction is a method of extraction, by boiling, of dissolved chemicals, or herbal or plant material, which may include stems, roots, bark and rhizomes. Decoction involves first mashing, and then boiling in water to extract oils, volatile organic compounds, and other chemical substances...

 of this fungus is used to help relieve the symptoms of gastralgia, or stomach ache
Abdominal pain
Abdominal pain can be one of the symptoms associated with transient disorders or serious disease. Making a definitive diagnosis of the cause of abdominal pain can be difficult, because many diseases can result in this symptom. Abdominal pain is a common problem...

.

Agricultural and industrial

Cyathus stercoreus has been investigated for its ability to break down lignin
Lignin
Lignin or lignen is a complex chemical compound most commonly derived from wood, and an integral part of the secondary cell walls of plants and some algae. The term was introduced in 1819 by de Candolle and is derived from the Latin word lignum, meaning wood...

 and cellulose
Cellulose
Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to over ten thousand β linked D-glucose units....

 in agricultural byproducts, like wheat
Wheat
Wheat is a cereal grain, originally from the Levant region of the Near East, but now cultivated worldwide. In 2007 world production of wheat was 607 million tons, making it the third most-produced cereal after maize and rice...

 straw or grasses. It selectively breaks down lignin, leaving much of the cellulose intact, which increases the amount of digestible carbohydrate
Carbohydrate
A carbohydrate is an organic compound with the empirical formula ; that is, consists only of carbon, hydrogen, and oxygen, with a hydrogen:oxygen atom ratio of 2:1 . However, there are exceptions to this. One common example would be deoxyribose, a component of DNA, which has the empirical...

 for ruminant
Ruminant
A ruminant is a mammal of the order Artiodactyla that digests plant-based food by initially softening it within the animal's first compartment of the stomach, principally through bacterial actions, then regurgitating the semi-digested mass, now known as cud, and chewing it again...

 mammals, and enhances both its value as a food source and its biodegradability
Biodegradation
Biodegradation or biotic degradation or biotic decomposition is the chemical dissolution of materials by bacteria or other biological means...

. The enzymes responsible, laccase
Laccase
Laccases are copper-containing oxidase enzymes that are found in many plants, fungi, and microorganisms. The copper is bound in several sites; Type 1, Type 2, and/or Type 3. The ensemble of types 2 and 3 copper is called a trinuclear cluster . Type 1 copper is available to action of solvents,...

 and manganese peroxidase
Manganese peroxidase
In enzymology, a manganese peroxidase is an enzyme that catalyzes the chemical reactionThe 3 substrates of this enzyme are Mn, H+, and H2O2, whereas its two products are Mn and H2O....

, also have industrial applications for lignin degradation and removal in the pulp and paper industry
Pulp and paper industry
The global pulp and paper industry is dominated by North American , northern European and East Asian countries...

. Liquid cultures of C. stercoreus have also been shown to biodegrade the explosive compound 2,4,6-trinitrotoluene (TNT).

Cited text

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