''Cyathus'' is a
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
of
fungi
A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from ...
in the
Nidulariaceae
The Nidulariaceae ('nidulus' - small nest) are a family of fungi in the order Agaricales. Commonly known as the bird's nest fungi, their fruiting bodies resemble tiny egg-filled birds' nests. As they are saprobic, feeding on decomposing organic ...
, a
family
Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...
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 reproductive structures containing
spore
In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, f ...
s. The "eggs", or ''peridioles'', are firmly attached to the inner surface of this
fruit body
In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the Ovary (plants), ovary after flowering plant, flowering.
Fruits are the means by which flowering plants (also known as angiosperms) disseminate their ...
by an elastic cord of
mycelia
Mycelium (plural mycelia) is a root-like structure of a fungus consisting of a mass of branching, thread-like hyphae. Fungal colonies composed of mycelium are found in and on soil and many other substrates. A typical single spore germinates in ...
known as a funiculus. The
45 species are widely distributed throughout the world and some are found in most countries, although a few exist in only one or two locales. ''
Cyathus stercoreus
''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'', family Nidulariaceae. Like other species in the Nidulariaceae, the fruiting bodies of ''C. sterc ...
'' is considered
endangered
An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inva ...
in a number of European countries. Species of ''Cyathus'' are also known as splash cups, which refers to the fact that falling raindrops can knock the peridioles out of the open-cup fruit body. The internal and external surfaces of this cup may be ridged longitudinally (referred to as
plicate or
striate
In geology, a striation is a groove, created by a geological process, on the surface of a rock or a mineral.
In structural geology, striations are linear furrows, or linear marks, generated from fault movement. The striation's direction revea ...
); this is one example of a
taxonomic
Taxonomy is the practice and science of categorization or classification.
A taxonomy (or taxonomical classification) is a scheme of classification, especially a hierarchical classification, in which things are organized into groups or types. ...
characteristic that has traditionally served to distinguish between species.
Generally considered inedible, ''Cyathus'' species are
saprobic
Saprotrophic nutrition or lysotrophic nutrition is a process of chemoheterotrophic extracellular digestion involved in the processing of decayed (dead or waste) organic matter. It occurs in saprotrophs, and is most often associated with fungi (f ...
, since they obtain nutrients from decomposing
organic matter
Organic matter, organic material, or natural organic matter refers to the large source of carbon-based compounds found within natural and engineered, terrestrial, and aquatic environments. It is matter composed of organic compounds that have c ...
. They usually grow on decaying wood or woody debris, on cow and horse dung, or directly on
humus
In classical soil science, humus is the dark organic matter in soil that is formed by the decomposition of plant and animal matter. It is a kind of soil organic matter. It is rich in nutrients and retains moisture in the soil. Humus is the Lati ...
-rich soil. The
life cycle
Life cycle, life-cycle, or lifecycle may refer to:
Science and academia
*Biological life cycle, the sequence of life stages that an organism undergoes from birth to reproduction ending with the production of the offspring
*Life-cycle hypothesis, ...
of this genus allows it to reproduce both sexually, with
meiosis
Meiosis (; , since it is a reductional division) is a special type of cell division of germ cells in sexually-reproducing organisms that produces the gametes, such as sperm or egg cells. It involves two rounds of division that ultimately resu ...
, and asexually via spores. Several ''Cyathus'' species produce
bioactive compounds, some with medicinal properties, and several
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 rigidity ...
-degrading
enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ...
s from the genus may be useful in
bioremediation
Bioremediation broadly refers to any process wherein a biological system (typically bacteria, microalgae, fungi, and plants), living or dead, is employed for removing environmental pollutants from air, water, soil, flue gasses, industrial effluent ...
and
agriculture
Agriculture or farming is the practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that enabled people to ...
.
Phylogenetic
In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...
analysis is providing new insights into the
evolution
Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation ...
ary relationships between the various species in ''Cyathus'', and has cast doubt on the validity of the older
classification Classification is a process related to categorization, the process in which ideas and objects are recognized, differentiated and understood.
Classification is the grouping of related facts into classes.
It may also refer to:
Business, organizat ...
systems that are based on traditional taxonomic characteristics
Taxonomy
History
Bird's nest fungi were first mentioned by Flemish botanist
Carolus Clusius
Charles de l'Écluse, L'Escluse, or Carolus Clusius (19 February 1526 – 4 April 1609), seigneur de Watènes, was an Artois doctor and pioneering botanist, perhaps the most influential of all 16th-century scientific horticulturists.
Life
Clu ...
in ''Rariorum plantarum historia'' (1601). Over the next couple of centuries, these fungi were the subject of some controversy regarding whether the peridioles were seeds, and the mechanism by which they were dispersed in nature. For example, the French botanist
Jean-Jacques Paulet
Jean-Jacques Paulet (26 April 1740 – 4 August 1826) was a French mycologist.
Paulet was born in Anduze, France and studied medicine in Montpellier, where he received his PhD in March 1764. He published in Paris in 1765 a book titled ''d’Histo ...
, in his work ''Traité des champignons'' (1790–3), proposed the erroneous notion that peridioles were ejected from the fruit bodies by some sort of spring mechanism.
[Brodie (1975), p. 15.] The genus was established in 1768 by the Swiss scientist
Albrecht von Haller
Albrecht von Haller (also known as Albertus de Haller; 16 October 170812 December 1777) was a Swiss anatomist, physiologist, naturalist, encyclopedist, bibliographer and poet. A pupil of Herman Boerhaave, he is often referred to as "the fa ...
; the
generic name ''Cyathus'' is
Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
, but originally derived from the
Ancient Greek
Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic peri ...
word κύαθος, meaning "cup".
The structure and biology of the genus ''Cyathus'' was better known by the mid-19th century, starting with the appearance in 1842 of a paper by Carl Johann Friedrich Schmitz,
and two years later, a
monograph
A monograph is a specialist work of writing (in contrast to reference works) or exhibition on a single subject or an aspect of a subject, often by a single author or artist, and usually on a scholarly subject.
In library cataloging, ''monograph ...
by the brothers
Louis René and
Charles Tulasne
Charles Tulasne (5 September 1816 – 28 August 1884) was a French physician, mycologist and illustrator born in Langeais in the département of Indre-et-Loire.
He received his medical doctorate in 1840 and practiced medicine in Paris until 185 ...
.
The work of the Tulasnes was thorough and accurate, and was highly regarded by later researchers.
Subsequently, monographs were written in 1902 by Violet S. White (on American species),
Curtis Gates Lloyd
Curtis Gates Lloyd (July 17, 1859 – November 11, 1926) was an American mycologist known for both his research on the gasteroid and polypore fungi, as well as his controversial views on naming conventions in taxonomy. He had a herbarium with ab ...
in 1906,
Gordon Herriot Cunningham
Gordon Herriot Cunningham, CBE, FRS (27 August 1892 – 18 July 1962) was the first New Zealand-based mycologist and plant pathologist. In 1936 he was appointed the first director of the DSIR Plant Diseases Division. Cunningham established the ...
in 1924 (on New Zealand species),
and
Harold J. Brodie in 1975.
Infrageneric classification
The genus ''Cyathus'' was first subdivided into two infrageneric groups (i.e., grouping species below the rank of genus) by the Tulasne brothers; the "eucyathus" group had fruit bodies with inner surfaces folded into
pleat
A pleat (plait in older English) is a type of fold formed by doubling fabric back upon itself and securing it in place. It is commonly used in clothing and upholstery to gather a wide piece of fabric to a narrower circumference.
Pleats are cat ...
s (plications), while the "olla" group lacked plications.
Later (1906),
Lloyd published a different concept of infrageneric grouping in ''Cyathus'', describing five groups, two in the eucyathus group and five in the olla group.
In the 1970s, Brodie, in his monograph on bird's nest fungi, separated the genus ''Cyathus'' into seven related groups based on a number of
taxonomic
Taxonomy is the practice and science of categorization or classification.
A taxonomy (or taxonomical classification) is a scheme of classification, especially a hierarchical classification, in which things are organized into groups or types. ...
characteristics, including the presence or absence of plications, the structure of the peridioles, the color of the fruit bodies, and the nature of the hairs on the outer peridium:
''Olla'' group: Species with a
tomentum
Tomentum may refer to:
* Plant trichomes, a covering of closely matted or fine hairs on plant leaves.
* Tomentum (anatomy), short, soft pubescence or a covering of fine, soft hairs.
{{disambig ...
having fine flattened-down hairs, and no plications.
* ''
C. olla'', ''C. africanus'', ''C. badius'', ''C. canna'', ''C. colensoi'', ''C. confusus'', ''C. earlei'', ''C. hookeri'', ''C. microsporus'', ''C. minimus'', ''C. pygmaeus''
''Pallidus'' group: Species with conspicuous, long, downward-pointing hairs, and a smooth (non-plicate) inner peridium.
* ''C. pallidus'', ''C. julietae''
''Triplex'' group: Species with mostly dark-colored peridia, and a silvery white inner surface.
* ''C. triplex'', ''C. setosus'', ''C. sinensis''
''Gracilis'' group: Species with tomentum hairs clumped into tufts or mounds.
* ''C. gracilis'', ''C. intermedius'', ''C. crassimurus'', ''C. elmeri''
![Cyathus striatus Uurrepesäsieni H7618 C](https://upload.wikimedia.org/wikipedia/commons/a/a6/Cyathus_striatus_Uurrepes%C3%A4sieni_H7618_C.jpg)
''Stercoreus'' group: Species with non-plicate peridia, shaggy or wooly outer peridium walls, and dark to black peridioles.
* ''C. stercoreus'', ''C. pictus'', ''C. fimicola''
''Poeppigii'' group: Species with plicate internal peridial walls, hairy to shaggy outer walls, dark to black peridioles, and large, roughly spherical or ellipsoidal spores.
* ''C. poeppigii'', ''C. crispus'', ''C. limbatus'', ''C. gayanus'', ''C. costatus'', ''C. cheliensis'', ''C. olivaceo-brunneus''
''Striatus'' group: Species with plicate internal peridia, hairy to shaggy outer peridia, and mostly elliptical spores.
* ''
C. striatus'', ''C. annulatus'', ''C. berkeleyanus'', ''C. bulleri'', ''C. chevalieri'', ''C. ellipsoideus'', ''
C. helenae'', ''C. montagnei'', ''C. nigro-albus'', ''C. novae-zeelandiae'', ''C. pullus'', ''C. rudis''
Phylogeny
The 2007 publication of
phylogenetic
In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...
analyses of
DNA sequence
DNA sequencing is the process of determining the nucleic acid sequence – the order of nucleotides in DNA. It includes any method or technology that is used to determine the order of the four bases: adenine, guanine, cytosine, and thymine. Th ...
data of numerous ''Cyathus'' species has cast doubt on the validity of the morphology-based infrageneric classifications described by Brodie. This research suggests that ''Cyathus'' species can be grouped into three genetically related
clade
A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...
s:
![Cyathus dominicanus](https://upload.wikimedia.org/wikipedia/commons/e/e1/Cyathus_dominicanus.png)
''ollum'' group: ''C. africanus'' (
type), ''C. africanus''
f. ''latisporus'', ''C. conlensoi'', ''C. griseocarpus'', ''C. guandishanensis'', ''C. hookeri'', ''C. jiayuguanensis'', ''
C. olla'', ''C. olla'' f. ''anglicus'', and ''C. olla'' f. ''brodiensis''.
''striatum'' group: ''C. annulatus'', ''C. crassimurus'', ''
C. helenae'', ''C. poeppigii'', ''C. renwei'', ''C. setosus'', ''
C. stercoreus'', and ''C. triplex''.
''pallidum'' group: ''C. berkeleyanus'', ''C. olla'' f. ''lanatus'', ''C. gansuensis'', and ''C. pallidus''.
This analysis shows that rather than fruit body structure,
spore
In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, f ...
size is generally a more reliable character for segregating species groups in ''Cyathus''.
For example, species in the ''ollum'' clade all have spore lengths less than 15 µm, while all members of the ''pallidum'' group have lengths greater than 15 µm; the ''striatum'' group, however, cannot be distinguished from the ''pallidum'' group by spore size alone. Two characteristics are most suited for distinguishing members of the ''ollum'' group from the ''pallidum'' group: the thickness of the hair layer on the peridium surface, and the outline of the fruit bodies. The tomentum of ''Pallidum'' species is thick, like felt, and typically aggregates into clumps of shaggy or woolly hair. Their crucible-shaped fruit bodies do not have a clearly differentiated stipe. The exoperidium of ''Ollum'' species, in comparison, has a thin tomentum of fine hairs; fruit bodies are funnel-shaped and have either a constricted base or a distinct
stipe.
Description
Species in the genus ''Cyathus'' have fruit bodies (
peridia) that are vase-, trumpet- or urn-shaped with dimensions of wide by tall.
[ Fruit bodies are brown to gray-brown in color, and covered with small hair-like structures on the outer surface. Some species, like '' C. striatus'' and ''C. setosus'', have conspicuous bristles called setae on the rim of the cup. The fruit body is often expanded at the base into a solid rounded mass of ]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 or ...
e called an emplacement, which typically becomes tangled and entwined with small fragments of the underlying growing surface, improving its stability and helping it from being knocked over by rain.
Immature fruit bodies have a whitish membrane, an epiphragm, that covers the peridium opening when young, but eventually dehisces
Dehiscence is the splitting of a mature plant structure along a built-in line of weakness to release its contents. This is common among fruits, anthers and sporangia. Sometimes this involves the complete detachment of a part; structures that op ...
, breaking open during maturation. Viewed with a microscope, the peridium of ''Cyathus'' species is made of three distinct layers—the endo-, meso-, and ectoperidium, referring to the inner, middle, and outer layers respectively. While the surface of the ectoperidium in ''Cyathus'' is usually hairy, the endoperidial surface is smooth, and depending on the species, may have longitudinal grooves (striations).[
Because the basic fruit body structure in all ]genera
Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclat ...
of the family Nidulariaceae is essentially similar, ''Cyathus'' may be readily confused with species of ''Nidula
''Nidula'' is a genus of fungi in the family Agaricaceae. Their fruit bodies resemble tiny egg-filled birds' nests, from which they derive their common name "bird's nest fungi". Originally described in 1902, the genus differs from the related gen ...
'' or ''Crucibulum
''Crucibulum'' is a genus in the Nidulariaceae, a family of fungi whose fruiting bodies resemble tiny egg-filled bird's nests. Often called "splash cups", the fruiting bodies are adapted for spore dispersal by using the kinetic energy of fall ...
'', especially older, weathered specimens of ''Cyathus'' that may have the hairy ectoperidium worn off. It distinguished from ''Nidula'' by the presence of a funiculus, a cord of hyphae attaching the peridiole to the endoperidium. ''Cyathus'' differs from genus ''Crucibulum'' by having a distinct three-layered wall and a more intricate funiculus.[
]
Peridiole structure
Derived from the Greek word ''peridion'', meaning "small leather pouch", the peridiole is the "egg" of the bird's nest. It is a mass of basidiospores
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 nucleus that is the product of meiosis, and they are pro ...
and gleba
Gleba (, from Latin ''glaeba, glēba'', "lump") is the fleshy spore-bearing inner mass of certain fungi such as the puffball or stinkhorn.
The gleba is a solid mass of spores, generated within an enclosed area within the sporocarp. The continu ...
l tissue enclosed by a hard and waxy outer shell. The shape may be described as lenticular—like a biconvex lens
A lens is a transmissive optical device which focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (''elements''), ...
—and depending on the species, may range in color from whitish to grayish to black. The interior chamber of the peridiole contains a hymenium
The hymenium is the tissue layer on the hymenophore of a fungal fruiting body where the cells develop into basidia or asci, which produce spores. In some species all of the cells of the hymenium develop into basidia or asci, while in others some ...
that is made of basidia
A basidium () is a microscopic sporangium (a spore-producing structure) found on the hymenophore of fruiting bodies of basidiomycete fungi which are also called tertiary mycelium, developed from secondary mycelium. Tertiary mycelium is highly-c ...
, sterile (non-reproductive) structures, and spores. In young, freshly opened fruit bodies, the peridioles lie in a clear gelatinous substance which soon dries.
Peridioles are attached to the fruit body by a funiculus, a complex structure of hyphae that may be 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. In some species the peridioles may be covered by a tunica, a thin white membrane (particularly evident in ''C. striatus'' and ''C. crassimurus'').
Spores typically have an elliptical or roughly spherical shape, and are thick-walled, hyaline
A hyaline substance is one with a glassy appearance. The word is derived from el, ὑάλινος, translit=hyálinos, lit=transparent, and el, ὕαλος, translit=hýalos, lit=crystal, glass, label=none.
Histopathology
Hyaline cartilage is ...
or light yellow-brown in color, with dimensions of 5–15 by 5–8 µm
The micrometre ( international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American spelling), also commonly known as a micron, is a unit of length in the International System of Unit ...
.[
]
Life cycle
The life cycle of the genus ''Cyathus'', which contains both haploid
Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Sets of chromosomes refer to the number of maternal and paternal chromosome copies, respectively ...
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. Sets of chromosomes refer to the number of maternal and paternal chromosome copies, respectively ...
stages, is typical of taxa
In biology, a taxon (back-formation from ''taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular nam ...
in the basidiomycetes
Basidiomycota () is one of two large 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. More specifically, Basi ...
that can reproduce both asexually (via vegetative spores), or sexually (with meiosis
Meiosis (; , since it is a reductional division) is a special type of cell division of germ cells in sexually-reproducing organisms that produces the gametes, such as sperm or egg cells. It involves two rounds of division that ultimately resu ...
). Like other wood-decay fungi, this life cycle may be considered as two functionally different phases: the vegetative stage for the spread of mycelia
Mycelium (plural mycelia) is a root-like structure of a fungus consisting of a mass of branching, thread-like hyphae. Fungal colonies composed of mycelium are found in and on soil and many other substrates. A typical single spore germinates in ...
, and the reproductive stage for the establishment of spore-producing structures, the fruit bodies.
The vegetative stage encompasses those phases of the life cycle involved with the germination, spread, and survival of the mycelium. Spores germinate under suitable conditions of moisture and temperature, and grow into branching filaments called hyphae, pushing out like roots into the rotting wood. These hyphae are homokaryotic Monokaryotic (adj.) is a term used to refer to multinucleate cells where all nuclei are genetically identical. In multinucleate cells, nuclei share one common cytoplasm, as is found in hyphal cells or mycelium of filamentous fungi.
See also
*Dika ...
, containing a single nucleus
Nucleus ( : nuclei) is a Latin word for the seed inside a fruit. It most often refers to:
*Atomic nucleus, the very dense central region of an atom
*Cell nucleus, a central organelle of a eukaryotic cell, containing most of the cell's DNA
Nucle ...
in each compartment; they increase in length by adding cell-wall material to a growing tip. As these tips expand and spread to produce new growing points, a network called the mycelium develops. Mycelial growth occurs by mitosis
In cell biology, mitosis () is a part of the cell cycle in which replicated chromosomes are separated into two new nuclei. Cell division by mitosis gives rise to genetically identical cells in which the total number of chromosomes is mainta ...
and the synthesis of hyphal biomass. When two homokaryotic hyphae of different mating compatibility groups fuse with one another, they form a dikaryotic The dikaryon is a cell nucleus, nuclear feature which 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 can fus ...
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 sta ...
. Prerequisites for mycelial survival and colonization a substrate (like rotting wood) include suitable humidity and nutrient availability. The majority of ''Cyathus'' species are saprobic
Saprotrophic nutrition or lysotrophic nutrition is a process of chemoheterotrophic extracellular digestion involved in the processing of decayed (dead or waste) organic matter. It occurs in saprotrophs, and is most often associated with fungi (f ...
, so mycelial growth in rotting wood is made possible by the secretion of enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ...
s that break down complex polysaccharide
Polysaccharides (), or polycarbohydrates, are the most abundant carbohydrates found in food. They are long chain polymeric carbohydrates composed of monosaccharide units bound together by glycosidic linkages. This carbohydrate can react with wa ...
s (such as cellulose
Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units. Cellulose is an important structural component of the primary cell wall ...
and 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 rigidity ...
) into simple sugars that can be used as nutrients.
After a period of time and under the appropriate environmental conditions, the dikaryotic mycelia may enter the reproductive stage of the life cycle. Fruit body formation is influenced by external factors such as season (which affects temperature and air humidity), nutrients and light. As fruit bodies develop they 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 basidiospores, each containing a single haploid nucleus. The dikaryotic mycelia from which the fruit bodies are produced is long lasting, and will continue to produce successive generations of fruit bodies as long as the environmental conditions are favorable.
The development of ''Cyathus'' fruit bodies has been studied in laboratory culture; ''C. stercoreus'' has been used most often for these studies due to the ease with which it may be grown experimentally. In 1958, E. Garnett first demonstrated that the development and form of the fruit bodies is at least partially dependent on the intensity of light it receives during development. For example, exposure of the heterokaryotic
A heterokaryon is a multinucleate cell that contains genetically different nuclei. Heterokaryotic and heterokaryosis are derived terms. This is a special type of syncytium. This can occur naturally, such as in the mycelium of fungi during sexual ...
mycelium to light is required for fruit to occur, and furthermore, this light needs to be at a wavelength
In physics, the wavelength is the spatial period of a periodic wave—the distance over which the wave's shape repeats.
It is the distance between consecutive corresponding points of the same phase on the wave, such as two adjacent crests, tro ...
of less than 530 nm. Continuous light is not required for fruit body development; after the mycelium has reached a certain stage of maturity, only a brief exposure to light is necessary, and fruit bodies will form if even subsequently kept in the dark. Lu suggested in 1965 that certain growing conditions—such as a shortage in available nutrients—shifts the fungus' metabolism
Metabolism (, from el, μεταβολή ''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 cell ...
to produce a hypothetical "photoreceptive precursor" that enables the growth of the fruit bodies to be stimulated and affected by light. The fungi is also positively phototropic
Phototropism is the growth of an organism in response to a light stimulus. Phototropism is most often observed in plants, but can also occur in other organisms such as fungi. The cells on the plant that are farthest from the light contain a hor ...
, that is, it will orient its fruit bodies in the direction of the light source. The time required to develop fruit bodies depends on a number of factors, such as the temperature, or the availability and type of nutrients, but in general "most species that do fruit in laboratory culture do so best at about 25 °C, in from 18 to 40 days."
Bioactive compounds
A number of species of ''Cyathus'' produce metabolites
In biochemistry, a metabolite is an intermediate or end product of metabolism.
The term is usually used for small molecules. Metabolites have various functions, including fuel, structure, signaling, stimulatory and inhibitory effects on enzymes, c ...
with biological activity, and novel chemical structures that are specific to this genus. For example, cyathin
''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 ...
s are diterpenoid
Diterpenes are a class of chemical compounds composed of four isoprene units, often with the molecular formula C20H32. They are biosynthesized by plants, animals and fungi via the HMG-CoA reductase pathway, with geranylgeranyl pyrophosphate being ...
compounds produced by '' C. helenae'', ''C. africanus'' and ''C. earlei''. Several of the cyathins (especially cyathins B3 and C3), including striatin compounds from ''C. striatus'', show strong antibiotic
An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention of ...
activity. Cyathane diterpenoids also stimulate nerve growth factor
Nerve growth factor (NGF) is a neurotrophic factor and neuropeptide primarily involved in the regulation of growth, maintenance, proliferation, and survival of certain target neurons. It is perhaps the prototypical growth factor, in that it was on ...
synthesis, and have the potential to be developed into therapeutic agents for neurodegenerative disorder
A neurodegenerative disease is caused by the progressive loss of structure or function of neurons, in the process known as neurodegeneration. Such neuronal damage may ultimately involve cell death. Neurodegenerative diseases include amyotrophic ...
s such as Alzheimer's disease
Alzheimer's disease (AD) is a neurodegeneration, neurodegenerative disease that usually starts slowly and progressively worsens. It is the cause of 60–70% of cases of dementia. The most common early symptom is difficulty in short-term me ...
. Compounds named cyathuscavins, isolated from the mycelial liquid culture of ''C. stercoreus'', have significant antioxidant
Antioxidants are compounds that inhibit oxidation, a chemical reaction that can produce free radicals. This can lead to polymerization and other chain reactions. They are frequently added to industrial products, such as fuels and lubricant ...
activity, as do the compounds known as cyathusals, also from ''C. stercoreus''. Various sesquiterpene
Sesquiterpenes are a class of terpenes that consist of three isoprene units and often have the molecular formula C15H24. Like monoterpenes, sesquiterpenes may be cyclic or contain rings, including many unique combinations. Biochemical modificatio ...
compounds have also been identified in ''C. bulleri'', including cybrodol (derived from humulene
Humulene, also known as α-humulene or α-caryophyllene, is a naturally occurring monocyclic sesquiterpene (C15H24), containing an 11-membered ring and consisting of 3 isoprene units containing three nonconjugated C=C double bonds, two of them be ...
), nidulol, and bullerone.
Distribution and habitat
Fruit bodies typically grow in clusters, and are found on dead or decaying wood, or on woody fragments in cow or horse dung. Dung-loving (coprophilous) species include '' C. stercoreus'', ''C. costatus'', ''C. fimicola'', and ''C. pygmaeus''. Some species have been collected on woody material like dead herbaceous
Herbaceous plants are vascular plants that have no persistent woody stems above ground. This broad category of plants includes many perennials, and nearly all annuals and biennials.
Definitions of "herb" and "herbaceous"
The fourth edition of t ...
stems, the empty shells or husk
Husk (or hull) in botany is the outer shell or coating of a seed. In the United States, the term husk often refers to the leafy outer covering of an ear of maize (corn) as it grows on the plant. Literally, a husk or hull includes the protective ...
s of nuts, or on fibrous material like coconut
The coconut tree (''Cocos nucifera'') is a member of the palm tree family ( Arecaceae) and the only living species of the genus ''Cocos''. The term "coconut" (or the archaic "cocoanut") can refer to the whole coconut palm, the seed, or the ...
, jute
Jute is a long, soft, shiny bast fiber that can be spun into coarse, strong threads. It is produced from flowering plants in the genus ''Corchorus'', which is in the mallow family Malvaceae. The primary source of the fiber is ''Corchorus olit ...
, or hemp
Hemp, or industrial hemp, is a botanical class of ''Cannabis sativa'' cultivars grown specifically for industrial or medicinal use. It can be used to make a wide range of products. Along with bamboo, hemp is among the fastest growing plants o ...
fiber woven into matting, sacks or cloth. In nature, fruit bodies are usually found in moist, partly shaded sites, such as the edges of woods on trails, or around lighted openings in forests. They are less frequently found growing in dense vegetation and deep mosses, as these environments would interfere with the dispersal of peridioles by falling drops of water.[Brodie (1975), p. 101.] The appearance of fruit bodies is largely dependent upon features of the immediate growing environment; specifically, optimum conditions of temperature, moisture, and nutrient availability are more important factors for fruit rather than the broad geographical area in which the fungi are located, or the season. Examples of the ability of ''Cyathus'' to thrive in somewhat inhospitable environments are provided by ''C. striatus'' and ''C. stercoreus'', which can survive the drought and cold of winter in temperate North America, and the species '' C. helenae'', which has been found growing on dead alpine plants
Alpine plants are plants that grow in an alpine climate, which occurs at high elevation and above the tree line. There are many different plant species and taxa that grow as a plant community in these alpine tundra. These include perennial grasses, ...
at an altitude of .
In general, species of ''Cyathus'' have a worldwide distribution Distribution may refer to:
Mathematics
*Distribution (mathematics), generalized functions used to formulate solutions of partial differential equations
* Probability distribution, the probability of a particular value or value range of a vari ...
, but are only rarely found in the arctic
The Arctic ( or ) is a polar regions of Earth, polar region located at the northernmost part of Earth. The Arctic consists of the Arctic Ocean, adjacent seas, and parts of Canada (Yukon, Northwest Territories, Nunavut), Danish Realm (Greenla ...
and subarctic
The subarctic zone is a region in the Northern Hemisphere immediately south of the true Arctic, north of humid continental regions and covering much of Alaska, Canada, Iceland, the north of Scandinavia, Siberia, and the Cairngorms. Generally, ...
.[Brodie (1975), p. 150.] One of the best known species, ''C. striatus'' has a circumpolar distribution and is commonly found throughout temperate
In geography, the temperate climates of Earth occur in the middle latitudes (23.5° to 66.5° N/S of Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ranges throughout t ...
locations, while the morphologically similar ''C. poeppigii'' is widely spread in tropical
The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in
the Southern Hemisphere at S. The tropics are also referred to ...
areas, rarely in the subtropics
The subtropical zones or subtropics are geographical and climate zones to the north and south of the tropics. Geographically part of the temperate zones of both hemispheres, they cover the middle latitudes from to approximately 35° north and ...
, and never in temperate regions. The majority of species are native to warm climates. For example, although 20 different species have been reported from the United States and Canada, only 8 are commonly encountered; on the other hand, 25 species may be regularly found in the West Indies
The West Indies is a subregion of North America, surrounded by the North Atlantic Ocean and the Caribbean Sea that includes 13 independent island countries and 18 dependencies and other territories in three major archipelagos: the Greater A ...
, and the Hawaiian Islands
The Hawaiian Islands ( haw, Nā Mokupuni o Hawai‘i) are an archipelago of eight major islands, several atolls, and numerous smaller islets in the North Pacific Ocean, extending some from the island of Hawaii in the south to northernmost Kur ...
alone have 11 species.[Brodie (1975), p. 117.] Some species seem to be endemic
Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...
to certain regions, such as ''C. novae-zeelandiae'' found in New Zealand
New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...
, or ''C. crassimurus'', found only in Hawaii; however, this apparent endemism may just be a result of a lack of collections, rather than a difference in the habitat that constitutes a barrier to spread. Although widespread in the tropics and most of the temperate world, ''C. stercoreus'' is only rarely found in Europe; this has resulted in its appearance on a number of Red Lists. For example, it is considered endangered
An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inva ...
in Bulgaria
Bulgaria (; bg, България, Bǎlgariya), officially the Republic of Bulgaria,, ) is a country in Southeast Europe. It is situated on the eastern flank of the Balkans, and is bordered by Romania to the north, Serbia and North Macedon ...
, Denmark
)
, song = ( en, "King Christian stood by the lofty mast")
, song_type = National and royal anthem
, image_map = EU-Denmark.svg
, map_caption =
, subdivision_type = Sovereign state
, subdivision_name = Danish Realm, Kingdom of Denmark
...
, and Montenegro
)
, image_map = Europe-Montenegro.svg
, map_caption =
, image_map2 =
, capital = Podgorica
, coordinates =
, largest_city = capital
, official_languages = M ...
, and "near threatened" in Great Britain
Great Britain is an island in the North Atlantic Ocean off the northwest coast of continental Europe. With an area of , it is the largest of the British Isles, the largest European island and the ninth-largest island in the world. It is ...
. The discovery of a ''Cyathus'' species in Dominican amber
Dominican amber is amber from the Dominican Republic derived from resin of the extinct tree ''Hymenaea protera''.
Dominican amber differentiates itself from Baltic amber by being nearly always transparent, and it has a higher number of fossil incl ...
('' C. dominicanus'') suggests that the basic form of the bird's nest fungi had already evolved by the Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...
era and that the group had diversified by the mid-Cenozoic
The Cenozoic ( ; ) is Earth's current geological era, representing the last 66million years of Earth's history. It is characterised by the dominance of mammals, birds and flowering plants, a cooling and drying climate, and the current configura ...
.
Ecology
Spore dispersal
Like other bird's nest fungi in the Nidulariaceae
The Nidulariaceae ('nidulus' - small nest) are a family of fungi in the order Agaricales. Commonly known as the bird's nest fungi, their fruiting bodies resemble tiny egg-filled birds' nests. As they are saprobic, feeding on decomposing organic ...
, species of ''Cyathus'' have their spores dispersed when water falls into the fruit body. The fruit body is shaped so that the kinetic energy of a fallen raindrop is redirected upward and slightly outward by the angle of the cup wall, which is consistently 70–75° with the horizontal. The action ejects the peridioles out of the so-called "splash cup", where it may break and spread the spores within, or be eaten and dispersed by animals after passing through the digestive tract. This method of spore dispersal in the Nidulariaceae was tested experimentally by George Willard Martin in 1924, and later elaborated by Arthur Henry Reginald Buller, who used ''C. striatus'' as the model species to experimentally investigate the phenomenon. Buller's major conclusions about spore dispersal were later summarized by his graduate student Harold J. Brodie, with whom he conducted several of these splash cup experiments: Raindrops cause the peridioles of the Nidulariaceae to be thrown about four feet by splash action. In the genus ''Cyathus'', as a peridiole is jerked out of its cup, the funiculus is torn and this makes possible the expansion of a mass of adhesive hyphae (the hapteron) which clings to any object in the line of flight. The momentum of the peridiole causes a long cord to be pulled out of a sheath attached to the peridiole. The peridiole is checked in flight and the jerk causes the funicular cord to become wound around stems or entangled among plant hairs. Thus the peridiole becomes attached to vegetation and may be eaten subsequently by herbivorous animals.
Although it has not been shown experimentally if the spores can survive the passage through an animal's digestive tract, the regular presence of ''Cyathus'' on cow or horse manure strongly suggest that this is true. Alternatively, the hard outer casing of peridioles ejected from splash cups may simply disintegrate over time, eventually releasing the spores within.
Uses
Species in the family Nidulariaceae, including ''Cyathus'', are considered inedible, as (in Brodie's words) they are "not sufficiently large, fleshy, or odorous to be of interest to humans as food". However, there have not been reports of poisonous alkaloid
Alkaloids are a class of basic, naturally occurring organic compounds that contain at least one nitrogen atom. This group also includes some related compounds with neutral and even weakly acidic properties. Some synthetic compounds of similar ...
s or other substances considered toxic to humans. Brodie goes on to note that two ''Cyathus'' species have been used by native peoples as an aphrodisiac
An aphrodisiac is a substance that increases sexual desire, sexual attraction, sexual pleasure, or sexual behavior. Substances range from a variety of plants, spices, foods, and synthetic chemicals. Natural aphrodisiacs like cannabis or cocain ...
, or to stimulate fertility
Fertility is the capability to produce offspring through reproduction following the onset of sexual maturity. The fertility rate is the average number of children born by a female during her lifetime and is quantified demographically. Fertili ...
: ''C. limbatus'' in Colombia
Colombia (, ; ), officially the Republic of Colombia, is a country in South America with insular regions in North America—near Nicaragua's Caribbean coast—as well as in the Pacific Ocean. The Colombian mainland is bordered by the Car ...
, and ''C. microsporus'' in Guadeloupe
Guadeloupe (; ; gcf, label=Antillean Creole, Gwadloup, ) is an archipelago and overseas department and region of France in the Caribbean. It consists of six inhabited islands—Basse-Terre, Grande-Terre, Marie-Galante, La Désirade, and the ...
. Whether these species have any actual effect on human physiology
The human body is the structure of a human being. It is composed of many different types of cells that together create tissues and subsequently organ systems. They ensure homeostasis and the viability of the human body.
It comprises a head ...
is unknown.[Brodie (1975), p. 120.]
Biodegradation
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 rigidity ...
is a complex polymeric chemical compound that is a major constituent of wood. Resistant to biological decomposition, its presence in paper makes it weaker and more liable to discolor when exposed to light. The species ''C. bulleri'' contains three lignin-degrading enzymes: lignin peroxidase
In enzymology, a lignin peroxidase () is an enzyme that catalyzes the chemical reaction
:1,2-bis(3,4-dimethoxyphenyl)propane-1,3-diol + H2O2 \rightleftharpoons 3,4-dimethoxybenzaldehyde + 1-(3,4-dimethoxyphenyl)ethane-1,2-diol + H2O
Thus, the ...
, manganese peroxidase
Manganese is a chemical element with the symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese is a transition metal with a multifaceted array of industrial alloy use ...
, and 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 lign ...
.[ These ]enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ...
s have potential applications not only in the pulp and paper industry
The pulp and paper industry comprises companies that use wood as raw material and produce pulp, paper, paperboard and other cellulose-based products.
Manufacturing process
The pulp is fed to a paper machine where it is formed as a paper web an ...
, but also to increase the digestibility and protein content of 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 ...
for cattle. Because laccases can break down phenolic compounds
In organic chemistry, phenols, sometimes called phenolics, are a class of chemical compounds consisting of one or more hydroxyl groups (— O H) bonded directly to an aromatic hydrocarbon group. The simplest is phenol, . Phenolic compounds are c ...
they may be used to detoxify some environmental pollutants, such as dye
A dye is a colored substance that chemically bonds to the substrate to which it is being applied. This distinguishes dyes from pigments which do not chemically bind to the material they color. Dye is generally applied in an aqueous solution an ...
s used in the textile industry
The textile industry is primarily concerned with the design, production and distribution of yarn, cloth and clothing. The raw material may be natural, or synthetic using products of the chemical industry.
Industry process
Cotton manufacturi ...
.[ ''C. bulleri'' laccase has also been ]genetically engineered
Genetic engineering, also called genetic modification or genetic manipulation, is the modification and manipulation of an organism's genes using technology. It is a set of technologies used to change the genetic makeup of cells, including t ...
to be produced by ''Escherichia coli
''Escherichia coli'' (),Wells, J. C. (2000) Longman Pronunciation Dictionary. Harlow ngland Pearson Education Ltd. also known as ''E. coli'' (), is a Gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus ''Escher ...
'', making it the first fungal laccase to be produced in a bacterial host.[ ''C. pallidus'' can ]biodegrade
Biodegradation is the breakdown of organic matter by microorganisms, such as bacteria and fungi. It is generally assumed to be a natural process, which differentiates it from composting. Composting is a human-driven process in which biodegradati ...
the explosive compound RDX
RDX (abbreviation of "Research Department eXplosive") or hexogen, among other names, is an organic compound with the formula (O2N2CH2)3. It is a white solid without smell or taste, widely used as an explosive. Chemically, it is classified as a n ...
(hexahydro-1,3,5-trinitro-1,3,5-triazine), suggesting it might be used to decontaminate munition
Ammunition (informally ammo) is the material fired, scattered, dropped, or detonated from any weapon or weapon system. Ammunition is both expendable weapons (e.g., bombs, missiles, grenades, land mines) and the component parts of other weapo ...
s-contaminated soils.[
]
Agriculture
'' Cyathus olla'' has been investigated for its ability to accelerate the decomposition of stubble left in the field after harvest, effectively reducing pathogen
In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ ...
populations and accelerating nutrient cycling
A nutrient cycle (or ecological recycling) is the movement and exchange of inorganic and organic matter back into the production of matter. Energy flow is a unidirectional and noncyclic pathway, whereas the movement of mineral nutrients is cycli ...
through mineralization
Mineralization may refer to:
* Mineralization (biology), when an inorganic substance precipitates in an organic matrix
** Biomineralization, a form of mineralization
** Mineralization of bone, an example of mineralization
** Mineralized tissues are ...
of essential plant nutrients.[
]
Human biology
Various ''Cyathus'' species have antifungal activity against human pathogens such as ''Aspergillus fumigatus
''Aspergillus fumigatus'' is a species of fungus in the genus ''Aspergillus'', and is one of the most common ''Aspergillus'' species to cause disease in individuals with an immunodeficiency.
''Aspergillus fumigatus'', a saprotroph widespread in ...
'', ''Candida albicans
''Candida albicans'' is an opportunistic pathogenic yeast that is a common member of the human gut flora. It can also survive outside the human body. It is detected in the gastrointestinal tract and mouth in 40–60% of healthy adults. It is us ...
'' and ''Cryptococcus neoformans
''Cryptococcus neoformans'' is an encapsulated yeast belonging to the class Tremellomycetes and an obligate aerobe that can live in both plants and animals. Its teleomorph is a filamentous fungus, formerly referred to ''Filobasidiella neoformans' ...
''. Extracts of ''C. striatus'' have inhibitory effects on NF-κB
Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) is a protein complex that controls transcription of DNA, cytokine production and cell survival. NF-κB is found in almost all animal cell types and is involved in cellular ...
, a transcription factor
In molecular biology, a transcription factor (TF) (or sequence-specific DNA-binding factor) is a protein that controls the rate of transcription of genetic information from DNA to messenger RNA, by binding to a specific DNA sequence. The fu ...
responsible for regulating the expression of several genes involved in the immune system
The immune system is a network of biological processes that protects an organism from diseases. It detects and responds to a wide variety of pathogens, from viruses to parasitic worms, as well as cancer cells and objects such as wood splinte ...
, inflammation
Inflammation (from la, wikt:en:inflammatio#Latin, inflammatio) is part of the complex biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or Irritation, irritants, and is a protective response involving im ...
, and cell death
Cell death is the event of a biological cell ceasing to carry out its functions. This may be the result of the natural process of old cells dying and being replaced by new ones, as in programmed cell death, or may result from factors such as dis ...
.
See also
* List of ''Cyathus'' species
References
Cited texts
*
*
*
External links
Trial field key to the species of BIRD'S NEST FUNGI in the Pacific Northwest
{{Taxonbar, from=Q1580329
Nidulariaceae
Agaricales genera