''Cyathus stercoreus'', commonly known as the dung-loving bird's nest or the dung bird's nest, is a species of fungus in the genus ''

Cyathus ''Cyathus'' is a genus of fungi in the Nidulariaceae, which is a family (biology), family collectively known as the bird's nest fungi. They are given this name as they resemble tiny bird's nests filled with "eggs"structures large enough to ...

'', family Nidulariaceae. 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 developed 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 In Taxonomy (biology), taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin gramm ...

is derived from the

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

word ''stercorarius'', meaning "of dung".Google Books
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Description

The fruiting bodies, or perida, 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 A hypha (; ) is a long, branching, filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium. Structure A hypha consists of one o ...

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, a structure of

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''. Cyathus-stercoreus-basidia

The

spore In biology, a spore is a unit of sexual reproduction, sexual (in fungi) or asexual reproduction that may be adapted for biological dispersal, dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores fo ...

s of ''C. stercoreus'' are roughly spherical and relatively large, with typical dimensions of 20–35 x 20–25 μm, although great variability in spore size has been noted.Brodie, ''The Bird's Nest Fungi'', p. 168. The spores are sessile (growing directly from the surface of the basidium, without attachment via a

sterigmata In biology, a sterigma (: sterigmata) is a small supporting structure. It commonly refers to an extension of the basidium (the spore-bearing cells) consisting of a basal filamentous part and a slender projection which carries a spore at the tip ...

), 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 A scanning electron microscope (SEM) is a type of electron microscope that produces images of a sample by scanning the surface with a focused beam of electrons. The electrons interact with atoms in the sample, producing various signals that ...

and

transmission electron microscopy Transmission electron microscopy (TEM) is a microscopy technique in which a beam of electrons is transmitted through a specimen to form an image. The specimen is most often an ultrathin section less than 100 nm thick or a suspension on a g ...

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.Flegler SL, Hooper GR. (1978). "Ultrastructure of ''Cyathus stercoreus''".''Mycologia'' 70(6): 1181–1190. Further, the funicular cord, known to be highly elastic and with a high

tensile strength Ultimate tensile strength (also called UTS, tensile strength, TS, ultimate strength or F_\text in notation) is the maximum stress that a material can withstand while being stretched or pulled before breaking. In brittle materials, the ultimate ...

, 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 Ploidy () is the number of complete sets of chromosomes in a cell (biology), cell, and hence the number of possible alleles for Autosome, autosomal and Pseudoautosomal region, pseudoautosomal genes. Here ''sets of chromosomes'' refers to the num ...

and

diploid Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Here ''sets of chromosomes'' refers to the number of maternal and paternal chromosome copies, ...

stages, is typical of taxa in the

basidiomycetes Basidiomycota () is one of two large division (mycology), divisions that, together with the Ascomycota, constitute the subkingdom Dikarya (often referred to as the "higher fungi") within the kingdom Fungi. Members are known as basidiomycetes. Mor ...

that can reproduce both asexually (via vegetative spores), or sexually (with

meiosis Meiosis () is a special type of cell division of germ cells in sexually-reproducing organisms that produces the gametes, the sperm or egg cells. It involves two rounds of division that ultimately result in four cells, each with only one c ...

Basidiospore A basidiospore is a reproductive spore produced by basidiomycete fungi, a grouping that includes mushrooms, shelf fungi, rusts, and smuts. Basidiospores typically each contain one haploid Ploidy () is the number of complete sets of chromos ...

s produced in the peridioles each contain a single haploid nucleus. After dispersal, the spores germinate and grow into homokaryotic hyphae, with a single nucleus in each compartment. When two homokaryotic

e of different mating compatibility groups fuse with one another, they form a

dikaryotic The dikaryon (karyogamy) is a cell nucleus feature that is unique to certain fungi. (The green alga ''Derbesia'' had been long considered an exception, until the heterokaryotic hypothesis was challenged by later studies.) Compatible cell-types ca ...

(containing two nuclei) mycelia in a process called

plasmogamy Plasmogamy is a stage in the sexual reproduction of fungi, in which the protoplasm of two parent cells (usually from the mycelia) fuse without the fusion of nuclei, effectively bringing two haploid nuclei close together in the same cell. This st ...

. 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 A basidium (: basidia) is a microscopic spore-producing structure found on the hymenophore of reproductive bodies of basidiomycete fungi. The presence of basidia is one of the main characteristic features of the group. These bodies are also ...

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 In biology, a heterokaryon is a multinucleate cell that contains genetically different nuclei. This is a special type of syncytium. This can occur naturally, such as in the mycelium of fungi during sexual reproduction, or artificially as formed by ...

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 ...

to light is required for fruiting to occur, and furthermore, this light needs to be at a

wavelength In physics and mathematics, wavelength or spatial period of a wave or periodic function is the distance over which the wave's shape repeats. In other words, it is the distance between consecutive corresponding points of the same ''phase (waves ...

of less than 530 nm. Lu suggests that certain growing conditions – such as a shortage in available nutrients – shifts the fungus'

metabolism Metabolism (, from ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cellular processes; the co ...

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

Habitat and distribution

Being coprophilous, ''C. stercoreus'' grows on dung, 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, 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 In organic chemistry, polyketides are a class of natural products derived from a Precursor (chemistry), precursor molecule consisting of a Polymer backbone, chain of alternating ketone (, or Carbonyl reduction, its reduced forms) and Methylene gro ...

-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 Deoxyribonucleic acid (; DNA) is a polymer composed of two polynucleotide chains that coil around each other to form a double helix. The polymer carries genetic instructions for the development, functioning, growth and reproduction of al ...

protection activity.

Uses

While inedible, the species has other uses.

Traditional medicine

Traditional Chinese medicine Traditional Chinese medicine (TCM) is an alternative medicine, alternative medical practice drawn from traditional medicine in China. A large share of its claims are pseudoscientific, with the majority of treatments having no robust evidence ...

, a

decoction Decoction is a method of extraction by boiling herbal or plant material (which may include stems, roots, bark and rhizomes) to dissolve the chemicals of the material. It is the most common preparation method in various herbal medicine systems. D ...

of this fungus is used to help relieve the symptoms of gastralgia, or stomach ache.

Agricultural and industrial

''Cyathus stercoreus'' has been investigated for its ability to break down

lignin Lignin is a class of complex organic polymers that form key structural materials in the support tissues of most plants. Lignins are particularly important in the formation of cell walls, especially in wood and bark, because they lend rigidit ...

and

cellulose Cellulose is an organic compound with the chemical formula, formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of glycosidic bond, β(1→4) linked glucose, D-glucose units. Cellulose is an important s ...

in agricultural byproducts, like

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 ...

straw Straw is an agricultural byproduct consisting of the dry wikt:stalk, stalks of cereal plants after the grain and chaff have been removed. It makes up about half of the crop yield, yield by weight of cereal crops such as barley, oats, rice, ry ...

or grasses. It selectively breaks down lignin, leaving much of the cellulose intact, which increases the amount of digestible

carbohydrate A carbohydrate () is a biomolecule composed of carbon (C), hydrogen (H), and oxygen (O) atoms. The typical hydrogen-to-oxygen atomic ratio is 2:1, analogous to that of water, and is represented by the empirical formula (where ''m'' and ''n'' ...

for

ruminant Ruminants are herbivorous grazing or browsing artiodactyls belonging to the suborder Ruminantia that are able to acquire nutrients from plant-based food by fermenting it in a specialized stomach prior to digestion, principally through microb ...

mammals, and enhances both its value as a food source and its biodegradability. The enzymes responsible,

laccase Laccases () are multicopper oxidases found in plants, fungi, and bacteria. Laccases oxidize a variety of phenolic substrates, performing one-electron oxidations, leading to crosslinking. For example, laccases play a role in the formation of li ...

and

manganese peroxidase In enzymology, a manganese peroxidase () is an enzyme that catalyzes the chemical reaction :2 Mn(II) + 2 H+ + H2O2 \rightleftharpoons 2 Mn(III) + 2 H2O The 3 substrates of this enzyme are Mn(II), H+, and H2O2, whereas its two products are M ...

, also have industrial applications for lignin degradation and removal in the

pulp and paper industry The pulp and paper industry comprises companies that use wood, specifically pulpwood, as raw material and produce pulp, paper, paperboard, and other cellulose-based products. Manufacturing process In the manufacturing process, pulp is intr ...

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

TNT Troponin T (shortened TnT or TropT) is a part of the troponin complex, which are proteins integral to the contraction of skeletal and heart muscles. They are expressed in skeletal and cardiac myocytes. Troponin T binds to tropomyosin and helps ...

).Chen J. (1995). "Development of fungal degrading system to detoxify 2,4,6-trinitrotoluene (TNT) in liquid phase bioreactors". PhD dissertation, Texas A&M University. 127 pp.

References

Cited text

External links

* {{Taxonbar, from=Q1265642 Nidulariaceae Medicinal fungi Fungi of Asia Fungi of Europe Fungi of North America Fungi of South America Fungi of Africa Fungi of Australia Fungi native to Australia Fungi described in 1888 Inedible fungi Taxa named by Lewis David de Schweinitz Fungus species