Panellus stipticus
Encyclopedia
Panellus stipticus, commonly known as the bitter oyster, the astringent panus, the luminescent panellus, or the stiptic fungus, is a species of fungus
in the Mycenaceae
family, and the type species
of the genus Panellus
. A common and widely distributed species, it is found in Asia, Australasia, Europe, and North America, where it grows in groups or dense overlapping clusters on the logs, stumps, and trunks of deciduous
trees, especially beech
, oak
, and birch
. During the development of the fruit bodies
, the mushrooms start out as tiny white knobs, which, over a period of one to three months, develop into fan- or kidney-shaped caps
that measure up to 3 cm (1.2 in) broad. The caps are orange-yellow to brownish, and attached to the decaying wood by short stubby stalks
that are connected off-center or on the side of the caps. The fungus was given its current scientific name
in 1879, but has been known by many names since French mycologist Jean Bulliard
first described it as Agaricus stypticus in 1783. Molecular phylogenetic analysis revealed P. stipticus to have a close genetic relationship with members of the genus Mycena
.
Panellus stipticus is one of several dozen species of fungi that are bioluminescent. Strains from eastern North America are typically bioluminescent, but those from the Pacific
regions of North America and from other continents are not. The luminescence is localized to the edges of the gills and the junction of the gills with the stem and cap. Bioluminescence is also observable with mycelia grown in laboratory culture, and the growth conditions for optimal light production have been studied in detail. Several chemicals have been isolated and characterized that are believed to be responsible for light production. Genetic analysis
has shown that luminescence is controlled by a single dominant allele. The luminescent glow of this and other fungi inspired the term foxfire
, coined by early settlers in eastern and southern North America. Modern research has probed the potential of P. stipticus as a tool in bioremediation
, due to its ability to detoxify various environmental pollutants.
in 1783, and later sanctioned
by Elias Magnus Fries
under this name in 1821. Fries later changed the genus as well as the spelling of the epithet and called it Panus stipticus. The species has had an extensive taxonomic
history and been shuffled to a number of genera
by various authors, resulting in several synonyms
: Agaricus flabelliformis (Johann Friedrich Gmelin
, 1792), Pocillaria stiptica (Otto Kuntze
, 1898), Rhipidium stipticum (Karl Friedrich Wilhelm Wallroth
, 1833), Crepidopus stipticus (Samuel Frederick Gray
, 1821), Pleurotus stipticus (Paul Kummer
), Lentinus stipticus (Joseph Schröter
, 1885), and Merulius stipticus (Jean-Baptiste Lamarck
). It was Finnish mycologist Petter Karsten who in 1879 assigned its current name. Panellus stypticus is still used in the literature as a variant spelling.
Panellus stipticus is the type species
of the genus Panellus, and, in Rolf Singer
's authoritative 1986 classification of the Agaricales
, it is also the type species of subgenus
Panellus, an infrageneric (below the taxonomic level of genus) grouping of Panellus species characterized by the absence of cystidia on the sides of the gills. More recently, phylogenetic analyses of the sequences of their ribosomal large subunit genes have concluded that Panellus stipticus is closely related to the poroid mushroom Dictyopanus pusillus. The molecular analysis supports a previous assessment by mycologists Harold Bursdall and Orson K. Miller, who in 1975 suggested merging Dictyopanus into Panellus based on similarities in spore shape, stem structure, and the ability of dried fruit bodies to revive when moistened. Formerly grouped in the Tricholomataceae
family, a wastebasket taxon of gilled mushrooms with white spores, P. stipticus is now classified in the Mycenaceae
, after a large-scale phylogenetic analysis revealed "a previously unsuspected relationship between Mycena and Panellus (including Dictyopanus)".
The fungus is commonly
known as the bitter oyster, the luminescent panellus, the astringent panus, or the styptic fungus. The specific epithet stipticus refers to its purported value in stopping bleeding. Etymologically
, it is a Greek
equivalent to the Latin
word astringens, deriving from στυπτικός (styptikós), itself from the verb στύφειν (styphein), "to contract".
cells called a mycelium
, inhabiting rotting wood; only when suitable environmental conditions of temperature, moisture, and nutrient availability are achieved does the fungus produce the reproductive structures known as fruit bodies
, or mushrooms. The cap
of the fruit body is kidney- or clamshell-shaped, convex to roughly flat, with dimensions of 1.2 to 3.2 cm (0.47244094488189 to 1.3 in) by 1.2 to 2.5 cm (0.47244094488189 to 0.984251968503937 in). The edges of the caps are scalloped with small rounded teeth, and curved slightly inward. The cap surface is dry, with a pattern of block-like areas similar to cracked dried mud; the surface is also covered with small fine hairs that give it a somewhat woolly consistency. It may have several concentric ridges or zones. Fresh fruit bodies range in color from yellowish-orange to buff to cinnamon; when dried they may be various shades of tan, brown or clay. The faded colors of dried fruit bodies tend to revive when moistened. On the underside of the cap, the gills are narrow and spaced closely together, often forked, buff-colored, and with numerous interconnecting cross-veins. Holding the cap in position is a stem
that is 0.6 to 1.2 cm (0.236220472440945 to 0.47244094488189 in) long by 0.3 to 0.8 cm (0.118110236220472 to 0.31496062992126 in) thick, and has an off-center attachment to the cap, either at or near the cap side. The dull-white stem is covered with minute silk-like fibers, and is narrower at the base where it attaches to the substrate
. Fruit bodies do not have any distinctive odor. The flesh
is thin and tough, and dark yellow-brown to cream-colored.
similar species. A spore print
of P. stipticus, made by depositing a large number of spores in a small area, reveals their color to be white. Viewed with a microscope
, the spores are smooth-walled, elliptical to nearly allantoid (sausage-shaped), with dimensions of 3–6 by 2–3 µm
. Spores are amyloid
, meaning that they will absorb iodine
and become bluish-black when stained with Melzer's reagent
, but this staining reaction has been described as "relatively weak".
The basidia (the spore-bearing cells) are 15–20 by 2.5–3.5 µm, club-shaped, and clamped at the base. The spores are attached to the end of the basidia by four projections called sterigmata that are 1–3.5 µm long. Cystidia are hyphal cells in the hymenium
that do not produce basidiospores; they also make up the surfaces of the fruit body (the pelli or "cuticles"). They are usually structurally distinct from the basidia, and their features may be used as microscopic characters to help distinguish and differentiate similar fungi. The cheilocystidia are found on the gill edge; in P. stipticus they are narrowly club-shaped, cylindrical, spindle-shaped to bifurcate at the apex. They are also thin-walled, hyaline
(translucent), abundant and crowded, and measure 17–45 by 3.5–6 µm. The pleurocystidia, located on the gill face, are 17–40 by 3–4.5 µm, spindle- or club-shaped, sometimes bifurcate at the apex, thin-walled, and hyaline. They are scattered or in dense clusters, mostly embedded in hymenium, occasionally protruding up to half the width of the hymenium.
The flesh
of the cap consists of a number of microscopically distinct layers of tissue. The cuticle of the cap (known as the pileipellis
) is between 8–10 µm thick, and is made of a loose textura intricata, a type of tissue in which the hyphae are irregularly interwoven with distinct spaces between them. The cuticle hyphae are thick-walled to thin-walled, with scattered inconspicuous cystidia measuring 40–55 by 3.5–5.5 µm. These cystidia located in the cap (pileocystidia) are cylindrical, thin-walled, yellow in Melzer's reagent, hyaline in KOH
, sometimes with amorphous dingy brown material coating the walls. Beneath the cuticle layer is a zone 54–65 µm thick, made of very loosely entwined, thin-walled hyphae, 2–3 µm in thickness, with clamps at the septa. Below this is a zone 208–221 µm in thickness, in which the densely compacted hyphae, 3–8 µm in diameter, have swollen, gelatinized walls, and often more or less a vertical orientation. This in turn is followed by a layer 520 µm in thickness, formed of loosely interwoven hyphae, 2–8 µm in width, some of which have thin walls with clamps at the septa, whilst others have somewhat thickened gelatinized walls. The flesh
of the cap has a layer of upright hyphae bending into a lower layer of interwoven hyphae with diameters of 2.5–8 µm. The flesh of the gills is similar to that of the lower cap.
having a similar shape can be distinguished by their brown spore print, compared with the white spore print of P. stipticus. Schizophyllum commune
has a densely hairy white to grayish cap and longitudinally split gill-folds on the underside. The ruddy panus mushroom (Panus rudis) is larger, has a reddish-brown cap that fades to pinkish-tan, and shows lilac tinges when young, fresh, and moist. Some Paxillus
species may have a similar appearance, but they have yellow-brown spore prints.
. Its taste has been described as acidic, acrid, or astringent. One 1992 study reported that the taste of the fruit bodies varies across the geographic range of the species. Those from eastern North America have a mildly acrid taste that took time to develop, and caused uncomfortable drying in the mouth. In contrast, specimens from Japan, New Zealand, and Russia produced no sensation in the mouth, but caused significant constriction and a nauseating taste in the throat. The fruit bodies are reputed to have been used in traditional Chinese medicine
as a styptic to staunch bleeding, and also as a "violent purgative
".
, which can be seen when the cap is about 2 mm in diameter.The young cap is spherical and its growth is at first epinastic, its margin being curved inwards and pressed against the stem. In this way, the hymenium begins its development within a special enclosed chamber. As the hymenial surface increases and keeps pace with the growth of the dorsal tissue of the cap, the latter expands and exposes the gills. The gills are formed by the continual downward growth of some of the hyphae. The gills are exposed before the cap is completely developed, and before the spores are mature. Spores can be produced by fruit bodies as small as 1.3 cm (0.511811023622047 in) broad, and liberation of the spores continues until the fruit body is fully grown—a period of one month to three months, depending on the conditions of temperature and moisture. The mature spores are disseminated by the wind. When the fruit body is nearing maturity, some of the terminal portions of the hyphae of the dorsal surface of the cap separate, and as a consequence, the upper surface of the fruit body becomes granular in appearance.
The fruit body projects out horizontally from the growing surface. If the position of a log is altered after young fruit bodies with the beginnings of gills have appeared, the stems of these attempt to readjust themselves in order to place the cap in a horizontal position. The cap are sometimes zonate (marked with concentric lines that form alternating pale and darker zones); this depends on changes in the humidity
of the environment, as variations in the amount of moisture will cause alternating periods of acceleration or slowing of growth.
A yellowish-brown pigment is diffused through the cytosol
of the hyphae and is much deeper in color just below the cuticle
of the cap. In very young fruit bodies, stems and caps are very pale buff, but soon the color of the cap deepens and becomes cinnamon. The intensity of the color appears to be dependent on light, for when fruit bodies are grown in diffuse light (temperature and humidity being constant) they are a uniform pale buff color, but in bright light they are cinnamon or tan.
regions of Europe, and has also been collected in Australia, New Zealand, Anatolia
, Japan, and China. In North America, it is more common in the east than the west; the mushroom's northern range extends to Alaska, and it has been collected as far south as Costa Rica
.
Panellus stipticus is a saprobic species, and causes a white rot. This is a form of wood decay in which the wood assumes a bleached appearance and where lignin
as well as cellulose
and hemicellulose
is broken down by enzyme
s secreted by the fungus. Fruit bodies are usually found in tightly overlapping clusters on the sides of hardwood trees, on logs, stumps, and fallen branches. Although most commonly found on dead wood, it can also grow opportunistically in the wounds of living trees. In North America, its preferred hosts are oak
, birch
, maple
, hickory
, pecan
, and American hornbeam
, while in Europe, it is commonly found growing on oak, birch, alder
, beech
, hazel
, chestnut
, and ash. It has also been found growing on Ericia in North Africa. Although the fungus favors hardwoods, it has been reported to grow on Loblolly Pine
and Eastern White Pine
. Fruiting occurs September through November in Europe, the Canary Islands
, and North America, although it may also sometimes be found in the spring. The fruit bodies are long-lasting and may be found year-round. It is an "early-stage" succession
fungus, not typically recorded from plantations over 20 years old.
The fruit bodies are frequently attacked by slugs, which may be important agents in the dispersal of its spores. White-tailed deer
are also known to consume the fungus.
, tetrapolar mating system
: each basidiospore develops into a self-sterile mycelium which, when grown alone, remains homokaryotic
(i.e., with all cells genetically identical) indefinitely. Researchers have paired collections of P. stipticus from Japan and Eastern North America, and later, collections from New Zealand and Russia. Although the separated allopatric
populations differ in bioluminescence and taste, the results revealed a universal intercompatibility group over these geographical regions. In a 2001 study, Jin and colleagues also paired geographically representative collections of the fungus, but observed a reduced ability to cross between Northern Hemisphere and Oceania
n collections, as well as between and within Oceanian collections.
Bioluminescence
refers to the ability of certain living things in the environment to produce light by the action of enzyme
s. Bioluminescent fungi are widespread, and over 60 species are known. Although the intensity of their luminescence is generally low compared to many other bioluminescent organisms, fungi glow continuously for days, so their total emission is comparable with that of most brightly luminescent organisms, such as fireflies
. Luminous fungi are found growing on decaying wood, leading to the popular name of "foxfire
" or "glow wood" when their glow is visible at night. The responsible oxidative enzyme
s—known generically as luciferase
s—produce light by oxidizing a pigment
called a luciferin
. In some areas, P. stypticus is bioluminescent, and the fruit bodies of these strains will glow in the dark when fresh or sometimes when revived in water after drying.
An early record of luminescence noted in P. stypticus was made by the American naturalist Thomas G. Gentry in 1885. Job Bicknell Ellis
, reporting on the phenomenon for the Journal of Mycology, wrote:
Canadian mycologist Buller
in 1924 described the gills of P. stipticus in North America as luminescent, and noted that the fungus glows most strongly at the time of spore maturation. Bioluminescence has not been observed in European specimens, in Pacific North American collections, nor in strains collected from New Zealand, Russia, and Japan. Although a number of reports have confirmed that eastern North American strains are luminescent, non-luminescent North American strains are also known. In general, the intensity of fungal bioluminescence decreases after exposure to certain contaminants; this sensitivity is being investigated as a means to develop bioluminescence-based biosensor
s to test the toxicity of polluted soils. Most known luminescent fungi are in the genus Mycena
or closely allied genera; this grouping of fungi—known as the "mycenoid lineage"—includes P. stipticus and three other Panellus species.
, have also been shown to be bioluminescent. Early studies demonstrated that short-wave ultraviolet
light (at a wavelength
of 280 nm
) reversibly inhibited the luminescence of P. stypticus mycelia, while longer wavelength (366 nm) ultraviolet was stimulatory. Further, the fungus exhibited a pronounced diurnal periodicity, and maximum luminescence was noted between 6 and 9 pm, regardless as to whether the mycelial cultures were incubated in continuous light, continuous darkness, or a normal day-night cycle. The mycelia of P. stipticus grown submerged in liquid were non-luminescent, but became luminescent while growing on solid substrata. Dark-grown colonies were luminescent in the center, and light-grown colonies were brightest at the periphery. Other experiments have shown that growth temperature and pH
have a significant effect on the level of bioluminescence, optimized at 22 °C (71.6 °F) and pH 3–3.5. However, light had a significant effect on mycelial growth but not on bioluminescence, and the optimal light conditions for maximum bioluminescence were total darkness.
, Macrae paired nonluminescent monocaryons with luminescent ones, and concluded that luminosity in P. stipticus is an inherited character, and governed by a single pair of allele
s in which luminosity was dominant over nonluminosity. Luminosity factors were independent of intersterility factors. In 1992, Lingle and colleagues agreed with Macrae about luminosity and stated that at least three different gene mutations
could lead to the loss of luminescence. They also reported that the maximum bioluminescence was found at 525 nm, and shifted to 528 nm in deeply pigmented fruit bodies.
After intercontinental compatibility tests, Petersen and Bermudes suggested that bioluminescence and compatibility were independent since bioluminescence seemed to be geographically restricted. This suggested that the ability or potential to interbreed must have been preserved since separation of P. stypticus into geographically isolated areas.
s to the fruit body to help disseminate spores. However, there has been no direct observation of this phenomenon. In many species, the mycelium is luminescent, but the fruit bodies is not, which argues against this hypothesis. Mycelial bioluminence may also function to attract animals that can potentially carry fungal spores in well-hydrated areas, as light emission from the mycelium is higher when it is hydrated. This would presumably increase the chance that spores would be deposited in an environment that is already optimal for growth. Basidiomycete mushrooms are known to be dependent on an adequate moisture supply for proper development. In species with a luminous mycelium, the mycelium would therefore have a dual function in performing the fungal translocation that permits transport of substances from the further environment back to the fruiting body, and in attracting disseminating vectors towards environments favorable for development of the species.
s, enzymes that produce light by the oxidation of a luciferin
(a pigment
). Several studies have evaluated the biochemical basis of light production in Panellus stipticus, and concluded that there is no specific fungal luciferase. The fungus was shown in 1988 to contain the sesquiterpene
panal, which has a cadinene
keto-aldehyde chemical structure. Later, two additional precursors were isolated, PS-A (1-O-decanoylpanal) and PS-B (1-O-dodecanoylpanal). If these compounds are treated with salt of ammonia
or primary amines in the presence of iron(II), hydrogen peroxide
, and a cationic surfactant
, light is emitted by a chemiluminescence reaction, suggesting that panal and its derivatives are fungal luciferins, and that the chemiluminescence reaction is the cause of in vivo
bioluminescence. In the fungus, the level of activity of the enzyme superoxide dismutase
(SOD) appears to play a critical role in the amount of light emission. SOD quenches the effect of the superoxide
(O2−) anion required in the reaction, and thus SOD activity has to be inhibited for the reaction to occur.
, a complex aromatic
polymer in wood that is highly resistant to degradation by conventional enzyme systems. The major enzyme that initiates the cleavage of hydrocarbon rings
is laccase
, which catalyzes
the addition of a hydroxyl
group to phenol
ic compounds (polyphenol
s). The ring can then be opened between the two adjacent carbon atoms that bear the hydroxyl groups. White-rot fungi are being investigated scientifically for their potential use in the bioremediation
of land contaminated by organic pollutants, and to convert industrial waste
s rich in toxic polyphenols. Panellus stipticus has been shown to reduce the phenolic concentration of waste water produced by olive-processing plants—an environmental concern in many Mediterranean countries. In this study, a liquid culture of P. stipticus mycelia reduced the initial concentration of phenolic compounds by 42% after a 31-day incubation period. In a separate study, a P. stipticus culture was able to effectively degrade the environmental pollutant 2,7-dichlorodibenzo-p-dioxin, a polychlorinated dioxin.
Fungus
A fungus is a member of a large 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, Fungi, which is separate from plants, animals, and bacteria...
in the Mycenaceae
Mycenaceae
The Mycenaceae are a family of fungi in the order Agaricales. According to the Dictionary of the Fungi , the family contains 10 genera and 705 species. This is one of several families that were separated from the Tricholomataceae as a result of phylogenetic analyses...
family, and the type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
of the genus Panellus
Panellus
Panellus is a genus of about 55 species of fungi in the Mycenaceae family.-Description:The fruit bodies of Panellus species are small- to medium-sized, and pleurotoid, meaning they grow on wood, have gills, and usually form semicircular or kidney-shaped caps that may be either directly attached to...
. A common and widely distributed species, it is found in Asia, Australasia, Europe, and North America, where it grows in groups or dense overlapping clusters on the logs, stumps, and trunks of deciduous
Deciduous
Deciduous means "falling off at maturity" or "tending to fall off", and is typically used in reference to trees or shrubs that lose their leaves seasonally, and to the shedding of other plant structures such as petals after flowering or fruit when ripe...
trees, especially beech
Beech
Beech is a genus of ten species of deciduous trees in the family Fagaceae, native to temperate Europe, Asia and North America.-Habit:...
, oak
Oak
An oak is a tree or shrub in the genus Quercus , of which about 600 species exist. "Oak" may also appear in the names of species in related genera, notably Lithocarpus...
, and birch
Birch
Birch is a tree or shrub of the genus Betula , in the family Betulaceae, closely related to the beech/oak family, Fagaceae. The Betula genus contains 30–60 known taxa...
. During the development of the fruit bodies
Basidiocarp
In fungi, a basidiocarp, basidiome or basidioma , is the sporocarp of a basidiomycete, the multicellular structure on which the spore-producing hymenium is borne. Basidiocarps are characteristic of the hymenomycetes; rusts and smuts do not produce such structures...
, the mushrooms start out as tiny white knobs, which, over a period of one to three months, develop into fan- or kidney-shaped caps
Pileus (mycology)
The pileus is the technical name for the cap, or cap-like part, of a basidiocarp or ascocarp that supports a spore-bearing surface, the hymenium. The hymenium may consist of lamellae, tubes, or teeth, on the underside of the pileus...
that measure up to 3 cm (1.2 in) broad. The caps are orange-yellow to brownish, and attached to the decaying wood by short stubby stalks
Stipe (mycology)
thumb|150px|right|Diagram of a [[basidiomycete]] stipe with an [[annulus |annulus]] and [[volva |volva]]In mycology a stipe refers to the stem or stalk-like feature supporting the cap of a mushroom. Like all tissues of the mushroom other than the hymenium, the stipe is composed of sterile hyphal...
that are connected off-center or on the side of the caps. The fungus was given its current scientific name
Binomial nomenclature
Binomial 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 grammatical forms, although they can be based on words from other languages...
in 1879, but has been known by many names since French mycologist Jean Bulliard
Jean Baptiste François Pierre Bulliard
Jean Baptiste François Pierre Bulliard was a French physician and botanist....
first described it as Agaricus stypticus in 1783. Molecular phylogenetic analysis revealed P. stipticus to have a close genetic relationship with members of the genus Mycena
Mycena
Mycena is a large genus of small saprotrophic mushrooms that are rarely more than a few centimeters in width. They are characterized by a white spore print, a small conical or bell-shaped cap, and a thin fragile stem. Most are gray or brown, but a few species have brighter colors. Most have a...
.
Panellus stipticus is one of several dozen species of fungi that are bioluminescent. Strains from eastern North America are typically bioluminescent, but those from the Pacific
Pacific Coast
A country's Pacific coast is the part of its coast bordering the Pacific Ocean.-The Americas:Countries on the western side of the Americas have a Pacific coast as their western border.* Geography of Canada* Geography of Chile* Geography of Colombia...
regions of North America and from other continents are not. The luminescence is localized to the edges of the gills and the junction of the gills with the stem and cap. Bioluminescence is also observable with mycelia grown in laboratory culture, and the growth conditions for optimal light production have been studied in detail. Several chemicals have been isolated and characterized that are believed to be responsible for light production. Genetic analysis
Genetic analysis
Genetic analysis can be used generally to describe methods both used in and resulting from the sciences of genetics and molecular biology, or to applications resulting from this research....
has shown that luminescence is controlled by a single dominant allele. The luminescent glow of this and other fungi inspired the term foxfire
Foxfire (bioluminescence)
Foxfire, also sometimes referred to as "fairy fire", is the bioluminescence created by some species of fungi present in decaying wood. The bluish green glow is attributed to luciferase, an oxidizing agent, which emits light as it reacts with luciferin...
, coined by early settlers in eastern and southern North America. Modern research has probed the potential of P. stipticus as a tool in bioremediation
Bioremediation
Bioremediation is the use of microorganism metabolism to remove pollutants. Technologies can be generally classified as in situ or ex situ. In situ bioremediation involves treating the contaminated material at the site, while ex situ involves the removal of the contaminated material to be treated...
, due to its ability to detoxify various environmental pollutants.
Taxonomy and phylogeny
The species was first named Agaricus stypticus by the French botanist Jean BulliardJean Baptiste François Pierre Bulliard
Jean Baptiste François Pierre Bulliard was a French physician and botanist....
in 1783, and later sanctioned
Sanctioned name
In mycology, a sanctioned name is a name that was adopted in certain works of Christiaan Hendrik Persoon or Elias Magnus Fries, which are considered major points in fungal taxonomy.-Definition and effects:...
by Elias Magnus Fries
Elias Magnus Fries
-External links:*, Authors of fungal names, Mushroom, the Journal of Wild Mushrooming.*...
under this name in 1821. Fries later changed the genus as well as the spelling of the epithet and called it Panus stipticus. The species has had an extensive taxonomic
Taxonomy
Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...
history and been shuffled to a number of genera
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
by various authors, resulting in several synonyms
Synonym (taxonomy)
In scientific nomenclature, a synonym is a scientific name that is or was used for a taxon of organisms that also goes by a different scientific name. For example, Linnaeus was the first to give a scientific name to the Norway spruce, which he called Pinus abies...
: Agaricus flabelliformis (Johann Friedrich Gmelin
Johann Friedrich Gmelin
Johann Friedrich Gmelin was a German naturalist, botanist, entomologist, herpetologist and malacologist.- Education :Johann Friedrich Gmelin was born as the eldest son of Philipp Friedrich Gmelin in 1748 in Tübingen...
, 1792), Pocillaria stiptica (Otto Kuntze
Otto Kuntze
Otto Carl Ernst Kuntze was a German botanist.-Biography:Otto Kuntze was born in Leipzig.An apothecary in his early career, he published an essay entitled Pocket Fauna of Leipzig. Between 1863 and...
, 1898), Rhipidium stipticum (Karl Friedrich Wilhelm Wallroth
Karl Friedrich Wilhelm Wallroth
Karl Friedrich Wilhelm Wallroth was a German botanist. His name is abbreviated Wallr. as a taxon authority.-References:...
, 1833), Crepidopus stipticus (Samuel Frederick Gray
Samuel Frederick Gray
Samuel Frederick Gray was a British botanist, mycologist, and pharmacologist. He was the father of the zoologists John Edward Gray and George Robert Gray.-Background:...
, 1821), Pleurotus stipticus (Paul Kummer
Paul Kummer
Paul Kummer was a priest, teacher, and scientist in Zerbst, Germany, known chiefly for his contribution to mycological nomenclature. Earlier classification of agarics by pioneering fungal taxonomist Elias Magnus Fries designated only a very small number of genera, with most species falling into...
), Lentinus stipticus (Joseph Schröter
Joseph Schröter
Joseph Schröter was a noted German mycologist, doctor and scientist. During his lifetime, he wrote several books and texts, and discovered and described many species of flora and fungi...
, 1885), and Merulius stipticus (Jean-Baptiste Lamarck
Jean-Baptiste Lamarck
Jean-Baptiste Pierre Antoine de Monet, Chevalier de la Marck , often known simply as Lamarck, was a French naturalist...
). It was Finnish mycologist Petter Karsten who in 1879 assigned its current name. Panellus stypticus is still used in the literature as a variant spelling.
Panellus stipticus is the type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
of the genus Panellus, and, in Rolf Singer
Rolf Singer
Rolf Singer was a German-born mycologist and one of the most important taxonomists of gilled mushrooms in the 20th century....
's authoritative 1986 classification of the Agaricales
Agaricales
The fungal order Agaricales, also known as gilled mushrooms , or euagarics, contains some of the most familiar types of mushrooms. The order has 33 extant families, 413 genera, and over 13000 described species, along with five extinct genera known only from the fossil record...
, it is also the type species of subgenus
Subgenus
In biology, a subgenus is a taxonomic rank directly below genus.In zoology, a subgeneric name can be used independently or included in a species name, in parentheses, placed between the generic name and the specific epithet: e.g. the Tiger Cowry of the Indo-Pacific, Cypraea tigris Linnaeus, which...
Panellus, an infrageneric (below the taxonomic level of genus) grouping of Panellus species characterized by the absence of cystidia on the sides of the gills. More recently, phylogenetic analyses of the sequences of their ribosomal large subunit genes have concluded that Panellus stipticus is closely related to the poroid mushroom Dictyopanus pusillus. The molecular analysis supports a previous assessment by mycologists Harold Bursdall and Orson K. Miller, who in 1975 suggested merging Dictyopanus into Panellus based on similarities in spore shape, stem structure, and the ability of dried fruit bodies to revive when moistened. Formerly grouped in the Tricholomataceae
Tricholomataceae
The Tricholomataceae are a large family of mushrooms within the Agaricales. A classic "wastebasket taxon", the Tricholomataceae is inclusive of any white-, yellow-, or pink-spored genera in the Agaricales not already classified as belonging to the Amanitaceae, Lepiotaceae, Hygrophoraceae,...
family, a wastebasket taxon of gilled mushrooms with white spores, P. stipticus is now classified in the Mycenaceae
Mycenaceae
The Mycenaceae are a family of fungi in the order Agaricales. According to the Dictionary of the Fungi , the family contains 10 genera and 705 species. This is one of several families that were separated from the Tricholomataceae as a result of phylogenetic analyses...
, after a large-scale phylogenetic analysis revealed "a previously unsuspected relationship between Mycena and Panellus (including Dictyopanus)".
The fungus is commonly
Common name
A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...
known as the bitter oyster, the luminescent panellus, the astringent panus, or the styptic fungus. The specific epithet stipticus refers to its purported value in stopping bleeding. Etymologically
Etymology
Etymology is the study of the history of words, their origins, and how their form and meaning have changed over time.For languages with a long written history, etymologists make use of texts in these languages and texts about the languages to gather knowledge about how words were used during...
, it is a Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
equivalent to the Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
word astringens, deriving from στυπτικός (styptikós), itself from the verb στύφειν (styphein), "to contract".
Description
The fungus normally exists unseen, in the form of a mass of threadlike vegetativeVegetative 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...
cells called a 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...
, inhabiting rotting wood; only when suitable environmental conditions of temperature, moisture, and nutrient availability are achieved does the fungus produce the reproductive structures known as fruit bodies
Basidiocarp
In fungi, a basidiocarp, basidiome or basidioma , is the sporocarp of a basidiomycete, the multicellular structure on which the spore-producing hymenium is borne. Basidiocarps are characteristic of the hymenomycetes; rusts and smuts do not produce such structures...
, or mushrooms. The cap
Pileus (mycology)
The pileus is the technical name for the cap, or cap-like part, of a basidiocarp or ascocarp that supports a spore-bearing surface, the hymenium. The hymenium may consist of lamellae, tubes, or teeth, on the underside of the pileus...
of the fruit body is kidney- or clamshell-shaped, convex to roughly flat, with dimensions of 1.2 to 3.2 cm (0.47244094488189 to 1.3 in) by 1.2 to 2.5 cm (0.47244094488189 to 0.984251968503937 in). The edges of the caps are scalloped with small rounded teeth, and curved slightly inward. The cap surface is dry, with a pattern of block-like areas similar to cracked dried mud; the surface is also covered with small fine hairs that give it a somewhat woolly consistency. It may have several concentric ridges or zones. Fresh fruit bodies range in color from yellowish-orange to buff to cinnamon; when dried they may be various shades of tan, brown or clay. The faded colors of dried fruit bodies tend to revive when moistened. On the underside of the cap, the gills are narrow and spaced closely together, often forked, buff-colored, and with numerous interconnecting cross-veins. Holding the cap in position is a stem
Stipe (mycology)
thumb|150px|right|Diagram of a [[basidiomycete]] stipe with an [[annulus |annulus]] and [[volva |volva]]In mycology a stipe refers to the stem or stalk-like feature supporting the cap of a mushroom. Like all tissues of the mushroom other than the hymenium, the stipe is composed of sterile hyphal...
that is 0.6 to 1.2 cm (0.236220472440945 to 0.47244094488189 in) long by 0.3 to 0.8 cm (0.118110236220472 to 0.31496062992126 in) thick, and has an off-center attachment to the cap, either at or near the cap side. The dull-white stem is covered with minute silk-like fibers, and is narrower at the base where it attaches to the substrate
Substrate (biology)
In biology a substrate is the surface a plant or animal lives upon and grows on. A substrate can include biotic or abiotic materials and animals. For example, encrusting algae that lives on a rock can be substrate for another animal that lives on top of the algae. See also substrate .-External...
. Fruit bodies do not have any distinctive odor. The flesh
Trama (mycology)
In mycology trama is a term for the inner, fleshy portion of a mushroom's basidiocarp, or fruit body. It is distinct from the outer layer of tissue, known as the pileipellis or cuticle, and from the spore-bearing tissue layer known as the hymenium....
is thin and tough, and dark yellow-brown to cream-colored.
Microscopic features
Various microscopic characteristics may be used to help identify the fungus from other morphologicallyMorphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
similar species. A spore print
Spore print
thumb|300px|right|Making a spore print of the mushroom Volvariella volvacea shown in composite: mushroom cap laid on white and dark paper; cap removed after 24 hours showing pinkish-tan spore print...
of P. stipticus, made by depositing a large number of spores in a small area, reveals their color to be white. Viewed with a microscope
Optical microscope
The optical microscope, often referred to as the "light microscope", is a type of microscope which uses visible light and a system of lenses to magnify images of small samples. Optical microscopes are the oldest design of microscope and were possibly designed in their present compound form in the...
, the spores are smooth-walled, elliptical to nearly allantoid (sausage-shaped), with dimensions of 3–6 by 2–3 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...
. Spores are amyloid
Amyloid (mycology)
In mycology the term amyloid refers to a crude chemical test using iodine in either Melzer's reagent or Lugol's solution, to produce a black to blue-black positive reaction. It is called amyloid because starch gives a similar reaction, and that reaction for starch is also called an amyloid reaction...
, meaning that they will absorb iodine
Iodine
Iodine is a chemical element with the symbol I and atomic number 53. The name is pronounced , , or . The name is from the , meaning violet or purple, due to the color of elemental iodine vapor....
and become bluish-black when stained with Melzer's reagent
Melzer's Reagent
Melzer's reagent is a chemical reagent used by mycologists to assist with the identification of fungi.-Composition:...
, but this staining reaction has been described as "relatively weak".
The basidia (the spore-bearing cells) are 15–20 by 2.5–3.5 µm, club-shaped, and clamped at the base. The spores are attached to the end of the basidia by four projections called sterigmata that are 1–3.5 µm long. Cystidia are hyphal cells in the hymenium
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 cells develop into sterile cells called cystidia or...
that do not produce basidiospores; they also make up the surfaces of the fruit body (the pelli or "cuticles"). They are usually structurally distinct from the basidia, and their features may be used as microscopic characters to help distinguish and differentiate similar fungi. The cheilocystidia are found on the gill edge; in P. stipticus they are narrowly club-shaped, cylindrical, spindle-shaped to bifurcate at the apex. They are also thin-walled, hyaline
Hyaline
The term hyaline denotes a substance with a glass-like appearance.-Histopathology:In histopathological medical usage, a hyaline substance appears glassy and pink after being stained with haematoxylin and eosin — usually it is an acellular, proteinaceous material...
(translucent), abundant and crowded, and measure 17–45 by 3.5–6 µm. The pleurocystidia, located on the gill face, are 17–40 by 3–4.5 µm, spindle- or club-shaped, sometimes bifurcate at the apex, thin-walled, and hyaline. They are scattered or in dense clusters, mostly embedded in hymenium, occasionally protruding up to half the width of the hymenium.
The flesh
Trama (mycology)
In mycology trama is a term for the inner, fleshy portion of a mushroom's basidiocarp, or fruit body. It is distinct from the outer layer of tissue, known as the pileipellis or cuticle, and from the spore-bearing tissue layer known as the hymenium....
of the cap consists of a number of microscopically distinct layers of tissue. The cuticle of the cap (known as the pileipellis
Pileipellis
thumb|300px||right|The cuticle of some mushrooms, such as [[Russula mustelina]] shown here, can be peeled from the cap, and may be useful as an identification feature....
) is between 8–10 µm thick, and is made of a loose textura intricata, a type of tissue in which the hyphae are irregularly interwoven with distinct spaces between them. The cuticle hyphae are thick-walled to thin-walled, with scattered inconspicuous cystidia measuring 40–55 by 3.5–5.5 µm. These cystidia located in the cap (pileocystidia) are cylindrical, thin-walled, yellow in Melzer's reagent, hyaline in KOH
Potassium hydroxide
Potassium hydroxide is an inorganic compound with the formula KOH, commonly called caustic potash.Along with sodium hydroxide , this colorless solid is a prototypical strong base. It has many industrial and niche applications. Most applications exploit its reactivity toward acids and its corrosive...
, sometimes with amorphous dingy brown material coating the walls. Beneath the cuticle layer is a zone 54–65 µm thick, made of very loosely entwined, thin-walled hyphae, 2–3 µm in thickness, with clamps at the septa. Below this is a zone 208–221 µm in thickness, in which the densely compacted hyphae, 3–8 µm in diameter, have swollen, gelatinized walls, and often more or less a vertical orientation. This in turn is followed by a layer 520 µm in thickness, formed of loosely interwoven hyphae, 2–8 µm in width, some of which have thin walls with clamps at the septa, whilst others have somewhat thickened gelatinized walls. The flesh
Trama (mycology)
In mycology trama is a term for the inner, fleshy portion of a mushroom's basidiocarp, or fruit body. It is distinct from the outer layer of tissue, known as the pileipellis or cuticle, and from the spore-bearing tissue layer known as the hymenium....
of the cap has a layer of upright hyphae bending into a lower layer of interwoven hyphae with diameters of 2.5–8 µm. The flesh of the gills is similar to that of the lower cap.
Similar species
Species of CrepidotusCrepidotus
Crepidotus is a genus of fungi in the family Crepidotaceae. Species of Crepidotus all have small, convex to fan-shaped sessile caps and grow on wood or plant debris...
having a similar shape can be distinguished by their brown spore print, compared with the white spore print of P. stipticus. Schizophyllum commune
Schizophyllum commune
Schizophyllum commune is a very common species of mushroom in the genus Schizophyllum. It is the world's most widely distributed mushroom, occurring on every continent except Antarctica....
has a densely hairy white to grayish cap and longitudinally split gill-folds on the underside. The ruddy panus mushroom (Panus rudis) is larger, has a reddish-brown cap that fades to pinkish-tan, and shows lilac tinges when young, fresh, and moist. Some Paxillus
Paxillus
Paxillus is a genus of mushrooms of which most are known to be poisonous or inedible. The widespread genus contains 15 species. Species include Paxillus involutus and Paxillus vernalis...
species may have a similar appearance, but they have yellow-brown spore prints.
Uses
Panellus stipticus is considered too small and bitter to be edibleEdible mushroom
Edible mushrooms are the fleshy and edible fruiting bodies of several species of fungi. Mushrooms belong to the macrofungi, because their fruiting structures are large enough to be seen with the naked eye. They can appear either below ground or above ground where they may be picked by hand...
. Its taste has been described as acidic, acrid, or astringent. One 1992 study reported that the taste of the fruit bodies varies across the geographic range of the species. Those from eastern North America have a mildly acrid taste that took time to develop, and caused uncomfortable drying in the mouth. In contrast, specimens from Japan, New Zealand, and Russia produced no sensation in the mouth, but caused significant constriction and a nauseating taste in the throat. The fruit bodies are reputed to have been used 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...
as a styptic to staunch bleeding, and also as a "violent purgative
Laxative
Laxatives are foods, compounds, or drugs taken to induce bowel movements or to loosen the stool, most often taken to treat constipation. Certain stimulant, lubricant, and saline laxatives are used to evacuate the colon for rectal and/or bowel examinations, and may be supplemented by enemas under...
".
Fruit body development
Fruit bodies first appear as tiny white knobs less than a cubic millimeter in size. In a day or two the knobs grow into a horizontal pyramidal mass, increasing in height as the hyphae lengthen. This is soon followed by the formation of a minute cap, and lengthening of the stem. The stem is about 1 mm long when the cap first begins to form. The hyphae that comprise the stem gradually cease to grow at their ends, and then start to branch, with many of the branches growing in a horizontal direction. This growth, indicated by the flattening and broadening out of the top of the stem, gives rise to the cap. The horizontally aligned hyphae grow vertical branches which remain more or less parallel, ultimately forming the dorsal tissue of the cap. Other similar downward-growing branches form the fertile hymeniumHymenium
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 cells develop into sterile cells called cystidia or...
, which can be seen when the cap is about 2 mm in diameter.The young cap is spherical and its growth is at first epinastic, its margin being curved inwards and pressed against the stem. In this way, the hymenium begins its development within a special enclosed chamber. As the hymenial surface increases and keeps pace with the growth of the dorsal tissue of the cap, the latter expands and exposes the gills. The gills are formed by the continual downward growth of some of the hyphae. The gills are exposed before the cap is completely developed, and before the spores are mature. Spores can be produced by fruit bodies as small as 1.3 cm (0.511811023622047 in) broad, and liberation of the spores continues until the fruit body is fully grown—a period of one month to three months, depending on the conditions of temperature and moisture. The mature spores are disseminated by the wind. When the fruit body is nearing maturity, some of the terminal portions of the hyphae of the dorsal surface of the cap separate, and as a consequence, the upper surface of the fruit body becomes granular in appearance.
The fruit body projects out horizontally from the growing surface. If the position of a log is altered after young fruit bodies with the beginnings of gills have appeared, the stems of these attempt to readjust themselves in order to place the cap in a horizontal position. The cap are sometimes zonate (marked with concentric lines that form alternating pale and darker zones); this depends on changes in the humidity
Humidity
Humidity is a term for the amount of water vapor in the air, and can refer to any one of several measurements of humidity. Formally, humid air is not "moist air" but a mixture of water vapor and other constituents of air, and humidity is defined in terms of the water content of this mixture,...
of the environment, as variations in the amount of moisture will cause alternating periods of acceleration or slowing of growth.
A yellowish-brown pigment is diffused through the cytosol
Cytosol
The cytosol or intracellular fluid is the liquid found inside cells, that is separated into compartments by membranes. For example, the mitochondrial matrix separates the mitochondrion into compartments....
of the hyphae and is much deeper in color just below the cuticle
Pileipellis
thumb|300px||right|The cuticle of some mushrooms, such as [[Russula mustelina]] shown here, can be peeled from the cap, and may be useful as an identification feature....
of the cap. In very young fruit bodies, stems and caps are very pale buff, but soon the color of the cap deepens and becomes cinnamon. The intensity of the color appears to be dependent on light, for when fruit bodies are grown in diffuse light (temperature and humidity being constant) they are a uniform pale buff color, but in bright light they are cinnamon or tan.
Distribution, habitat, and ecology
Panellus stipticus is common in northern temperateTemperate
In geography, temperate or tepid latitudes of the globe lie between the tropics and the polar circles. The changes in these regions between summer and winter are generally relatively moderate, rather than extreme hot or cold...
regions of Europe, and has also been collected in Australia, New Zealand, Anatolia
Anatolia
Anatolia is a geographic and historical term denoting the westernmost protrusion of Asia, comprising the majority of the Republic of Turkey...
, Japan, and China. In North America, it is more common in the east than the west; the mushroom's northern range extends to Alaska, and it has been collected as far south as Costa Rica
Costa Rica
Costa Rica , officially the Republic of Costa Rica is a multilingual, multiethnic and multicultural country in Central America, bordered by Nicaragua to the north, Panama to the southeast, the Pacific Ocean to the west and the Caribbean Sea to the east....
.
Panellus stipticus is a saprobic species, and causes a white rot. This is a form of wood decay in which the wood assumes a bleached appearance and where 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...
as well as 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....
and hemicellulose
Hemicellulose
A hemicellulose is any of several heteropolymers , such as arabinoxylans, present along with cellulose in almost all plant cell walls. While cellulose is crystalline, strong, and resistant to hydrolysis, hemicellulose has a random, amorphous structure with little strength...
is broken down by enzyme
Enzyme
Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...
s secreted by the fungus. Fruit bodies are usually found in tightly overlapping clusters on the sides of hardwood trees, on logs, stumps, and fallen branches. Although most commonly found on dead wood, it can also grow opportunistically in the wounds of living trees. In North America, its preferred hosts are oak
Oak
An oak is a tree or shrub in the genus Quercus , of which about 600 species exist. "Oak" may also appear in the names of species in related genera, notably Lithocarpus...
, birch
Birch
Birch is a tree or shrub of the genus Betula , in the family Betulaceae, closely related to the beech/oak family, Fagaceae. The Betula genus contains 30–60 known taxa...
, maple
Maple
Acer is a genus of trees or shrubs commonly known as maple.Maples are variously classified in a family of their own, the Aceraceae, or together with the Hippocastanaceae included in the family Sapindaceae. Modern classifications, including the Angiosperm Phylogeny Group system, favour inclusion in...
, hickory
Hickory
Trees in the genus Carya are commonly known as hickory, derived from the Powhatan language of Virginia. The genus includes 17–19 species of deciduous trees with pinnately compound leaves and big nuts...
, pecan
Pecan
The pecan , Carya illinoinensis, is a species of hickory, native to south-central North America, in Mexico from Coahuila south to Jalisco and Veracruz, in the United States from southern Iowa, Illinois, Missouri, and Indiana east to western Kentucky, southwestern Ohio, North Carolina, South...
, and American hornbeam
American Hornbeam
Carpinus caroliniana is a small hardwood tree in the genus Carpinus. American hornbeam is also occasionally known as blue-beech, ironwood, or musclewood. It is native to eastern North America, from Minnesota and southern Ontario east to Maine, and south to eastern Texas and northern Florida...
, while in Europe, it is commonly found growing on oak, birch, alder
Alder
Alder is the common name of a genus of flowering plants belonging to the birch family . The genus comprises about 30 species of monoecious trees and shrubs, few reaching large size, distributed throughout the North Temperate Zone and in the Americas along the Andes southwards to...
, beech
Beech
Beech is a genus of ten species of deciduous trees in the family Fagaceae, native to temperate Europe, Asia and North America.-Habit:...
, hazel
Hazel
The hazels are a genus of deciduous trees and large shrubs native to the temperate northern hemisphere. The genus is usually placed in the birch family Betulaceae, though some botanists split the hazels into a separate family Corylaceae.They have simple, rounded leaves with double-serrate margins...
, chestnut
Chestnut
Chestnut , some species called chinkapin or chinquapin, is a genus of eight or nine species of deciduous trees and shrubs in the beech family Fagaceae, native to temperate regions of the Northern Hemisphere. The name also refers to the edible nuts they produce.-Species:The chestnut belongs to the...
, and ash. It has also been found growing on Ericia in North Africa. Although the fungus favors hardwoods, it has been reported to grow on Loblolly Pine
Loblolly Pine
Pinus taeda is one of several pines native to the Southeastern United States, from central Texas east to Florida, and north to Delaware. It is particularly dominant in the eastern half of North Carolina, where there are huge expanses consisting solely of Loblolly Pine trees...
and Eastern White Pine
Eastern White Pine
Pinus strobus, commonly known as the eastern white pine, is a large pine native to eastern North America, occurring from Newfoundland west to Minnesota and southeastern Manitoba, and south along the Appalachian Mountains to the northern edge of Georgia.It is occasionally known as simply white pine,...
. Fruiting occurs September through November in Europe, the Canary Islands
Canary Islands
The Canary Islands , also known as the Canaries , is a Spanish archipelago located just off the northwest coast of mainland Africa, 100 km west of the border between Morocco and the Western Sahara. The Canaries are a Spanish autonomous community and an outermost region of the European Union...
, and North America, although it may also sometimes be found in the spring. The fruit bodies are long-lasting and may be found year-round. It is an "early-stage" succession
Ecological succession
Ecological succession, is the phenomenon or process by which a community progressively transforms itself until a stable community is formed. It is a fundamental concept in ecology, and refers to more or less predictable and orderly changes in the composition or structure of an ecological community...
fungus, not typically recorded from plantations over 20 years old.
The fruit bodies are frequently attacked by slugs, which may be important agents in the dispersal of its spores. White-tailed deer
White-tailed Deer
The white-tailed deer , also known as the Virginia deer or simply as the whitetail, is a medium-sized deer native to the United States , Canada, Mexico, Central America, and South America as far south as Peru...
are also known to consume the fungus.
Mating studies
Panellus stipticus uses a heterothallicHeterothallic
Heterothallic species have sexes that reside in different individuals....
, tetrapolar mating system
Mating in fungi
Mating in fungi is a complex process governed by mating types. Research on fungal mating has focused on only a few model species. Since not all of the fungi reproduce sexually and many that do are isogamous, the terms male and female do not apply to this kingdom...
: each basidiospore develops into a self-sterile mycelium which, when grown alone, remains homokaryotic
Homokaryotic
Homokaryotic refers to multinucleate cells where all nuclei are genetically identical. It is the antonym of heterokaryotic....
(i.e., with all cells genetically identical) indefinitely. Researchers have paired collections of P. stipticus from Japan and Eastern North America, and later, collections from New Zealand and Russia. Although the separated allopatric
Allopatric speciation
Allopatric speciation or geographic speciation is speciation that occurs when biological populations of the same species become isolated due to geographical changes such as mountain building or social changes such as emigration...
populations differ in bioluminescence and taste, the results revealed a universal intercompatibility group over these geographical regions. In a 2001 study, Jin and colleagues also paired geographically representative collections of the fungus, but observed a reduced ability to cross between Northern Hemisphere and Oceania
Oceania
Oceania is a region centered on the islands of the tropical Pacific Ocean. Conceptions of what constitutes Oceania range from the coral atolls and volcanic islands of the South Pacific to the entire insular region between Asia and the Americas, including Australasia and the Malay Archipelago...
n collections, as well as between and within Oceanian collections.
Bioluminescence
Bioluminescence
Bioluminescence is the production and emission of light by a living organism. Its name is a hybrid word, originating from the Greek bios for "living" and the Latin lumen "light". Bioluminescence is a naturally occurring form of chemiluminescence where energy is released by a chemical reaction in...
refers to the ability of certain living things in the environment to produce light by the action of enzyme
Enzyme
Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...
s. Bioluminescent fungi are widespread, and over 60 species are known. Although the intensity of their luminescence is generally low compared to many other bioluminescent organisms, fungi glow continuously for days, so their total emission is comparable with that of most brightly luminescent organisms, such as fireflies
Firefly
Lampyridae is a family of insects in the beetle order Coleoptera. They are winged beetles, and commonly called fireflies or lightning bugs for their conspicuous crepuscular use of bioluminescence to attract mates or prey. Fireflies produce a "cold light", with no infrared or ultraviolet frequencies...
. Luminous fungi are found growing on decaying wood, leading to the popular name of "foxfire
Foxfire (bioluminescence)
Foxfire, also sometimes referred to as "fairy fire", is the bioluminescence created by some species of fungi present in decaying wood. The bluish green glow is attributed to luciferase, an oxidizing agent, which emits light as it reacts with luciferin...
" or "glow wood" when their glow is visible at night. The responsible oxidative enzyme
Oxidative enzyme
An oxidative enzyme is an enzyme that catalyses oxidation reaction. Two most common types of oxidative enzymes are peroxidases, which use hydrogen peroxide, and oxidases, which use molecular oxygen.They increase the rate at which ATP is produced aerobically....
s—known generically as luciferase
Luciferase
Luciferase is a generic term for the class of oxidative enzymes used in bioluminescence and is distinct from a photoprotein. One famous example is the firefly luciferase from the firefly Photinus pyralis. "Firefly luciferase" as a laboratory reagent usually refers to P...
s—produce light by oxidizing a pigment
Pigment
A pigment is a material that changes the color of reflected or transmitted light as the result of wavelength-selective absorption. This physical process differs from fluorescence, phosphorescence, and other forms of luminescence, in which a material emits light.Many materials selectively absorb...
called a luciferin
Luciferin
Luciferins are a class of light-emitting biological pigments found in organisms that cause bioluminescence...
. In some areas, P. stypticus is bioluminescent, and the fruit bodies of these strains will glow in the dark when fresh or sometimes when revived in water after drying.
An early record of luminescence noted in P. stypticus was made by the American naturalist Thomas G. Gentry in 1885. Job Bicknell Ellis
Job Bicknell Ellis
Job Bicknell Ellis was a pioneering North American mycologist known for his study of the Ascomycetes, especially the grouping of fungi called the Pyrenomycetes . Born and raised in New York, he worked as a teacher and farmer before developing an interest in mycology...
, reporting on the phenomenon for the Journal of Mycology, wrote:
"By careful examination, the luminosity was found to proceed from the gills and not the stipe, nor from any fragment of rotten wood attached to the specimen. This phosphoresence was not observed in all specimens brought in for examination, and seemed to depend on some peculiar condition of the air, having been noticed only in specimens gathered in damp weather or just before a storm."
Canadian mycologist Buller
Arthur Henry Reginald Buller
Arthur Henry Reginald Buller was a British-Canadian mycologist. He is mainly known as a researcher of fungi and wheat rust.- Academic career :...
in 1924 described the gills of P. stipticus in North America as luminescent, and noted that the fungus glows most strongly at the time of spore maturation. Bioluminescence has not been observed in European specimens, in Pacific North American collections, nor in strains collected from New Zealand, Russia, and Japan. Although a number of reports have confirmed that eastern North American strains are luminescent, non-luminescent North American strains are also known. In general, the intensity of fungal bioluminescence decreases after exposure to certain contaminants; this sensitivity is being investigated as a means to develop bioluminescence-based biosensor
Biosensor
A biosensor is an analytical device for the detection of an analyte that combines a biological component with a physicochemical detector component.It consists of 3 parts:* the sensitive biological element A biosensor is an analytical device for the detection of an analyte that combines a biological...
s to test the toxicity of polluted soils. Most known luminescent fungi are in the genus Mycena
Mycena
Mycena is a large genus of small saprotrophic mushrooms that are rarely more than a few centimeters in width. They are characterized by a white spore print, a small conical or bell-shaped cap, and a thin fragile stem. Most are gray or brown, but a few species have brighter colors. Most have a...
or closely allied genera; this grouping of fungi—known as the "mycenoid lineage"—includes P. stipticus and three other Panellus species.
Mycelia
The mycelia of this species, grown in laboratory cultureIn vitro
In vitro refers to studies in experimental biology that are conducted using components of an organism that have been isolated from their usual biological context in order to permit a more detailed or more convenient analysis than can be done with whole organisms. Colloquially, these experiments...
, have also been shown to be bioluminescent. Early studies demonstrated that short-wave ultraviolet
Ultraviolet
Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...
light (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 280 nm
Nanometre
A nanometre is a unit of length in the metric system, equal to one billionth of a metre. The name combines the SI prefix nano- with the parent unit name metre .The nanometre is often used to express dimensions on the atomic scale: the diameter...
) reversibly inhibited the luminescence of P. stypticus mycelia, while longer wavelength (366 nm) ultraviolet was stimulatory. Further, the fungus exhibited a pronounced diurnal periodicity, and maximum luminescence was noted between 6 and 9 pm, regardless as to whether the mycelial cultures were incubated in continuous light, continuous darkness, or a normal day-night cycle. The mycelia of P. stipticus grown submerged in liquid were non-luminescent, but became luminescent while growing on solid substrata. Dark-grown colonies were luminescent in the center, and light-grown colonies were brightest at the periphery. Other experiments have shown that growth temperature and pH
PH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...
have a significant effect on the level of bioluminescence, optimized at 22 °C (71.6 °F) and pH 3–3.5. However, light had a significant effect on mycelial growth but not on bioluminescence, and the optimal light conditions for maximum bioluminescence were total darkness.
Fruit bodies
Bioluminescent tissue in the mature fruit body is restricted to the edge of the gills (as well as the cross-veins that connect them), the junction of the gills with the stem, and the inrolled cap edge. Distribution of bioluminescence along the gill edge corresponds to the position of the cheilocystidia. Less than 10% of the light emitted from both the young and mature fruit bodies is from other tissues, including the fertile hymenial area and the stem. Fruit body luminescence is highly variable between fruit bodies found on different logs in different environments.Genetics
Using techniques of genetic complementationComplementation (genetics)
In genetics, complementation refers to a relationship between two different strains of an organism which both have homozygous recessive mutations that produce the same phenotype . These strains are true breeding for their mutation...
, Macrae paired nonluminescent monocaryons with luminescent ones, and concluded that luminosity in P. stipticus is an inherited character, and governed by a single pair of allele
Allele
An allele is one of two or more forms of a gene or a genetic locus . "Allel" is an abbreviation of allelomorph. Sometimes, different alleles can result in different observable phenotypic traits, such as different pigmentation...
s in which luminosity was dominant over nonluminosity. Luminosity factors were independent of intersterility factors. In 1992, Lingle and colleagues agreed with Macrae about luminosity and stated that at least three different gene mutations
Mutation
In molecular biology and genetics, mutations are changes in a genomic sequence: the DNA sequence of a cell's genome or the DNA or RNA sequence of a virus. They can be defined as sudden and spontaneous changes in the cell. Mutations are caused by radiation, viruses, transposons and mutagenic...
could lead to the loss of luminescence. They also reported that the maximum bioluminescence was found at 525 nm, and shifted to 528 nm in deeply pigmented fruit bodies.
After intercontinental compatibility tests, Petersen and Bermudes suggested that bioluminescence and compatibility were independent since bioluminescence seemed to be geographically restricted. This suggested that the ability or potential to interbreed must have been preserved since separation of P. stypticus into geographically isolated areas.
Function
Several authors have suggested that the purpose of fungal bioluminescence is to attract arthropodArthropod
An arthropod is an invertebrate animal having an exoskeleton , a segmented body, and jointed appendages. Arthropods are members of the phylum Arthropoda , and include the insects, arachnids, crustaceans, and others...
s to the fruit body to help disseminate spores. However, there has been no direct observation of this phenomenon. In many species, the mycelium is luminescent, but the fruit bodies is not, which argues against this hypothesis. Mycelial bioluminence may also function to attract animals that can potentially carry fungal spores in well-hydrated areas, as light emission from the mycelium is higher when it is hydrated. This would presumably increase the chance that spores would be deposited in an environment that is already optimal for growth. Basidiomycete mushrooms are known to be dependent on an adequate moisture supply for proper development. In species with a luminous mycelium, the mycelium would therefore have a dual function in performing the fungal translocation that permits transport of substances from the further environment back to the fruiting body, and in attracting disseminating vectors towards environments favorable for development of the species.
Chemical basis
In general, bioluminescence is caused by the action of luciferaseLuciferase
Luciferase is a generic term for the class of oxidative enzymes used in bioluminescence and is distinct from a photoprotein. One famous example is the firefly luciferase from the firefly Photinus pyralis. "Firefly luciferase" as a laboratory reagent usually refers to P...
s, enzymes that produce light by the oxidation of a luciferin
Luciferin
Luciferins are a class of light-emitting biological pigments found in organisms that cause bioluminescence...
(a pigment
Pigment
A pigment is a material that changes the color of reflected or transmitted light as the result of wavelength-selective absorption. This physical process differs from fluorescence, phosphorescence, and other forms of luminescence, in which a material emits light.Many materials selectively absorb...
). Several studies have evaluated the biochemical basis of light production in Panellus stipticus, and concluded that there is no specific fungal luciferase. The fungus was shown in 1988 to contain the sesquiterpene
Sesquiterpene
Sesquiterpenes are a class of terpenes that consist of three isoprene units and have the molecular formula C15H24. Like monoterpenes, sesquiterpenes may be acyclic or contain rings, including many unique combinations...
panal, which has a cadinene
Cadinene
Cadinene is the trivial chemical name of a number of isomeric hydrocarbons that occur in a wide variety of essential oil-producing plants. The name is derived from that of the Cade juniper , the wood of which yields an oil from which cadinene isomers were first isolated.Chemically, the cadinenes...
keto-aldehyde chemical structure. Later, two additional precursors were isolated, PS-A (1-O-decanoylpanal) and PS-B (1-O-dodecanoylpanal). If these compounds are treated with salt of ammonia
Ammonia
Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...
or primary amines in the presence of iron(II), hydrogen peroxide
Hydrogen peroxide
Hydrogen peroxide is the simplest peroxide and an oxidizer. Hydrogen peroxide is a clear liquid, slightly more viscous than water. In dilute solution, it appears colorless. With its oxidizing properties, hydrogen peroxide is often used as a bleach or cleaning agent...
, and a cationic surfactant
Surfactant
Surfactants are compounds that lower the surface tension of a liquid, the interfacial tension between two liquids, or that between a liquid and a solid...
, light is emitted by a chemiluminescence reaction, suggesting that panal and its derivatives are fungal luciferins, and that the chemiluminescence reaction is the cause of in vivo
In vivo
In vivo is experimentation using a whole, living organism as opposed to a partial or dead organism, or an in vitro controlled environment. Animal testing and clinical trials are two forms of in vivo research...
bioluminescence. In the fungus, the level of activity of the enzyme superoxide dismutase
Superoxide dismutase
Superoxide dismutases are a class of enzymes that catalyze the dismutation of superoxide into oxygen and hydrogen peroxide. As such, they are an important antioxidant defense in nearly all cells exposed to oxygen...
(SOD) appears to play a critical role in the amount of light emission. SOD quenches the effect of the superoxide
Superoxide
A superoxide, also known by the obsolete name hyperoxide, is a compound that possesses the superoxide anion with the chemical formula O2−. The systematic name of the anion is dioxide. It is important as the product of the one-electron reduction of dioxygen O2, which occurs widely in nature...
(O2−) anion required in the reaction, and thus SOD activity has to be inhibited for the reaction to occur.
Bioremediation
As a white-rot fungus, Panellus stipticus contains enzymes that are able to break down ligninLignin
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...
, a complex aromatic
Aromaticity
In organic chemistry, Aromaticity is a chemical property in which a conjugated ring of unsaturated bonds, lone pairs, or empty orbitals exhibit a stabilization stronger than would be expected by the stabilization of conjugation alone. The earliest use of the term was in an article by August...
polymer in wood that is highly resistant to degradation by conventional enzyme systems. The major enzyme that initiates the cleavage of hydrocarbon rings
Aromatic hydrocarbon
An aromatic hydrocarbon or arene is a hydrocarbon with alternating double and single bonds between carbon atoms. The term 'aromatic' was assigned before the physical mechanism determining aromaticity was discovered, and was derived from the fact that many of the compounds have a sweet scent...
is 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,...
, which catalyzes
Enzyme catalysis
Enzyme catalysis is the catalysis of chemical reactions by specialized proteins known as enzymes. Catalysis of biochemical reactions in the cell is vital due to the very low reaction rates of the uncatalysed reactions....
the addition of a hydroxyl
Hydroxyl
A hydroxyl is a chemical group containing an oxygen atom covalently bonded with a hydrogen atom. In inorganic chemistry, the hydroxyl group is known as the hydroxide ion, and scientists and reference works generally use these different terms though they refer to the same chemical structure in...
group to phenol
Phenol
Phenol, also known as carbolic acid, phenic acid, is an organic compound with the chemical formula C6H5OH. It is a white crystalline solid. The molecule consists of a phenyl , bonded to a hydroxyl group. It is produced on a large scale as a precursor to many materials and useful compounds...
ic compounds (polyphenol
Polyphenol
Polyphenols are a structural class of natural, synthetic, and semisynthetic organic chemicals characterized by the presence of large multiples of phenol structural units...
s). The ring can then be opened between the two adjacent carbon atoms that bear the hydroxyl groups. White-rot fungi are being investigated scientifically for their potential use in the bioremediation
Bioremediation
Bioremediation is the use of microorganism metabolism to remove pollutants. Technologies can be generally classified as in situ or ex situ. In situ bioremediation involves treating the contaminated material at the site, while ex situ involves the removal of the contaminated material to be treated...
of land contaminated by organic pollutants, and to convert industrial waste
Industrial waste
Industrial waste is a type of waste produced by industrial activity, such as that of factories, mills and mines. It has existed since the outset of the industrial revolution....
s rich in toxic polyphenols. Panellus stipticus has been shown to reduce the phenolic concentration of waste water produced by olive-processing plants—an environmental concern in many Mediterranean countries. In this study, a liquid culture of P. stipticus mycelia reduced the initial concentration of phenolic compounds by 42% after a 31-day incubation period. In a separate study, a P. stipticus culture was able to effectively degrade the environmental pollutant 2,7-dichlorodibenzo-p-dioxin, a polychlorinated dioxin.
External links
- Luxgene.com Photographs of luminescent P. stipticus fruit bodies and mycelium