Fallacinol (teloschistin) is an

organic compound Some chemical authorities define an organic compound as a chemical compound that contains a carbon–hydrogen or carbon–carbon bond; others consider an organic compound to be any chemical compound that contains carbon. For example, carbon-co ...

in the structural class of chemicals known as

anthraquinone Anthraquinone, also called anthracenedione or dioxoanthracene, is an aromatic hydrocarbon, aromatic organic compound with formula . Several isomers exist but these terms usually refer to 9,10-anthraquinone (IUPAC: 9,10-dioxoanthracene) wherein th ...

s. It is found in some

lichen A lichen ( , ) is a hybrid colony (biology), colony of algae or cyanobacteria living symbiotically among hypha, filaments of multiple fungus species, along with yeasts and bacteria embedded in the cortex or "skin", in a mutualism (biology), m ...

s, particularly in the family

Teloschistaceae The Teloschistaceae are a large family (biology), family of mostly lichen-forming fungi belonging to the class (taxonomy), class Lecanoromycetes in the division (botany), division Ascomycota. The family has a cosmopolitan distribution, althoug ...

, as well as a couple of plants and non lichen-forming fungi. In 1936, Japanese chemists isolated a pigment they named fallacin from the lichen '' Oxneria fallax'', which was later refined and assigned a tentative

structural formula The structural formula of a chemical compound is a graphic representation of the molecular structure (determined by structural chemistry methods), showing how the atoms are connected to one another. The chemical bonding within the molecule is al ...

; by 1949, Indian chemists had isolated a substance from ''

Teloschistes flavicans ''Teloschistes flavicans'', also known as the golden hair-lichen, is a lichenized species of fungus in the genus ''Teloschistes'' (meaning "split-ends"; a reference to the plant's finely divided thallus and dense coils which appear almost like Br ...

'' with an identical structural formula to fallacin. Later research further separated fallacin into two distinct pigments, fallacin-A (later called fallacinal) and fallacin-B (fallacinol). The latter compound is also known as teloschistin due to its structural match with the substance isolated earlier.

History

In 1936, Japanese chemists Mitizo Asano and Sinobu Fuziwara reported on their chemical investigations into the colour

pigments A pigment is a powder used to add or alter color or change visual appearance. Pigments are completely or nearly solubility, insoluble and reactivity (chemistry), chemically unreactive in water or another medium; in contrast, dyes are colored sub ...

of the lichen ''Xanthoria fallax'' (now known as '' Oxneria fallax''), found growing on the bark of

mulberry ''Morus'', a genus of flowering plants in the family Moraceae, consists of 19 species of deciduous trees commonly known as mulberries, growing wild and under cultivation in many temperate world regions. Generally, the genus has 64 subordinat ...

trees. They isolated a

pigment A pigment is a powder used to add or alter color or change visual appearance. Pigments are completely or nearly solubility, insoluble and reactivity (chemistry), chemically unreactive in water or another medium; in contrast, dyes are colored sub ...

they named fallacin. A few years later Asano and Yosio Arata further purified the crude material from this lichen, ultimately obtaining an orange-yellow compound with a

molecular formula A chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, such as paren ...

of C₁₆H₁₂O₆. Using information from additional chemical tests, they proposed a tentative

for fallacin. In 1949,

T. R. Seshadri Thiruvengadam Rajendram Seshadri FNA, FRS was an Indian chemist, academic, writer and the Head of the Department of Chemistry at the University of Delhi, known for his researches on the Indian medicinal and other plants. He was a Fellow of the ...

and S. Subramanian published their investigations into the chemistry of ''

'', a lichen from which they isolated an orange substance they named teloschistin, and which had a structural formula identical to that of fallacin proposed by Asano and Arata years earlier. In 1956, Takao Murakami reported reexamining the crude pigment obtainable from ''Xanthoria fallax'' using Asano's original 1936 procedure. He separated out fallacin from

parietin Parietin is the predominant cortical pigment of lichens in the genus '' Caloplaca'', a secondary product of the lichen '' Xanthoria parietina'', and a pigment found in the roots of curled dock (''Rumex crispus''). It has an orange-yellow color ...

, a co-occurring substance, using several rounds of

column chromatography Column chromatography in chemistry is a chromatography method used to isolate a single chemical compounds, chemical compound from a mixture. Chromatography is able to separate substances based on differential absorption of compounds to the adsorbe ...

, and showed that Asano's original pigment was actually a combination of two pigments with different

melting point The melting point (or, rarely, liquefaction point) of a substance is the temperature at which it changes state of matter, state from solid to liquid. At the melting point the solid and liquid phase (matter), phase exist in Thermodynamic equilib ...

s, which he designated as fallacin-A and fallacin-B. After chemically determining the structure of fallacin-A, Murakami designated this substance as fallacinal. He named the biogenically related compound fallacin-B as fallacinol. Because of Seshadri and Subramanian's work, this substance is also known as "teloschistin" in the

literature Literature is any collection of Writing, written work, but it is also used more narrowly for writings specifically considered to be an art form, especially novels, Play (theatre), plays, and poetry, poems. It includes both print and Electroni ...

Extraction and isolation

In an early chemical examination of the lichen ''

'',

Friedrich Wilhelm Zopf Friedrich (or Friederich) Wilhelm Zopf (12 December 1846 – 24 June 1909) was a well-known German botanist and mycologist. He dedicated to his whole life with fungal biology, particularly in classification of fungi and dye production in fungi an ...

identified two substances:

physcion Parietin is the predominant Cortex (botany), cortical pigment of lichens in the genus ''Caloplaca'', a secondary metabolism, secondary product of the lichen ''Xanthoria parietina'', and a biological pigment, pigment found in the roots of curled do ...

(now known more commonly as parietin) with a melting point (m.p.) of and an unidentified colourless compound with a m.p. of . Subsequent studies by Seshadri and Sankara Subramanian refined the extraction process, utilising a series of

solvent A solvent (from the Latin language, Latin ''wikt:solvo#Latin, solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a Solution (chemistry), solution. A solvent is usually a liquid but can also be a solid, a gas ...

s—

ether In organic chemistry, ethers are a class of compounds that contain an ether group, a single oxygen atom bonded to two separate carbon atoms, each part of an organyl group (e.g., alkyl or aryl). They have the general formula , where R and R� ...

acetone Acetone (2-propanone or dimethyl ketone) is an organic compound with the chemical formula, formula . It is the simplest and smallest ketone (). It is a colorless, highly Volatile organic compound, volatile, and flammable liquid with a charact ...

, and water—to isolate the constituents. The ether phase was found to contain all the crystalline compounds, while subsequent solvents did not yield additional extracts. Within the ether extract, a colourless compound, referred to as substance A, was separated based on its insolubility in

alkali In chemistry, an alkali (; from the Arabic word , ) is a basic salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as a base that dissolves in water. A solution of a soluble base has a pH greater than 7.0. The a ...

. The alkali-soluble

fraction A fraction (from , "broken") represents a part of a whole or, more generally, any number of equal parts. When spoken in everyday English, a fraction describes how many parts of a certain size there are, for example, one-half, eight-fifths, thre ...

exhibited characteristics of parietin, though impurities complicated its purification. It was eventually purified to a parietin fraction with a melting point of after multiple stages of fractional crystallisation using an

alcohol Alcohol may refer to: Common uses * Alcohol (chemistry), a class of compounds * Ethanol, one of several alcohols, commonly known as alcohol in everyday life ** Alcohol (drug), intoxicant found in alcoholic beverages ** Alcoholic beverage, an alco ...

chloroform Chloroform, or trichloromethane (often abbreviated as TCM), is an organochloride with the formula and a common solvent. It is a volatile, colorless, sweet-smelling, dense liquid produced on a large scale as a precursor to refrigerants and po ...

mixture. The presence of another compound with a higher melting point posed a purification challenge, which was resolved by employing

petroleum ether Petroleum ether is the petroleum fraction consisting of aliphatic hydrocarbons and boiling in the range 35–60 °C, and commonly used as a laboratory solvent. Despite the name, petroleum ether is not an ether; the term is used only figurativ ...

and chloroform for sequential extraction. The petroleum ether extract contained the colourless substance A and a majority of parietin, allowing for easier purification of the latter. The chloroform extract revealed the higher-melting compound, which the authors thought was a novel substance, and which they named "teloschistin". In 1951, Neelakantan and colleagues expanded on the initial identification of fallacinol, focusing on its chemical structure. They confirmed its

as C₁₆H₁₂O₆ and identified it as a

hydroxyl In chemistry, a hydroxy or hydroxyl group is a functional group with the chemical formula and composed of one oxygen atom covalently bonded to one hydrogen atom. In organic chemistry, alcohols and carboxylic acids contain one or more hydroxy ...

derivative of parietin, lacking specific hydroxy groupings that would typically cause

fluorescence Fluorescence is one of two kinds of photoluminescence, the emission of light by a substance that has absorbed light or other electromagnetic radiation. When exposed to ultraviolet radiation, many substances will glow (fluoresce) with colore ...

or colour changes in acidic conditions. To conclusively determine the position of its

methoxyl group In organic chemistry, a methoxy group is the functional group consisting of a methyl group bound to oxygen. This alkoxy group has the formula . On a benzene ring, the Hammett equation classifies a methoxy substituent at the ''para'' position as ...

, fallacinol was chemically altered into a compound with a known methoxyl position, establishing it firmly in the 7-position. This process involved a series of reactions, including

demethylation Demethylation is the chemical process resulting in the removal of a methyl group (CH3) from a molecule. A common way of demethylation is the replacement of a methyl group by a hydrogen atom, resulting in a net loss of one carbon and two hydrogen at ...

, reduction, and oxidation. Additionally, comparisons with similar anthraquinone derivatives through

hydrolysis Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution reaction, substitution, elimination reaction, elimination, and solvation reactions in which water ...

and other reactions further substantiated the structural findings. The research also noted the slower-than-expected reaction rates during oxidation, suggesting a distinctive reactivity pattern for fallacinol, possibly due to its additional hydroxyl group. Finally, the study described the anthranol form of fallacinol, providing a reference for its properties and transformative behaviour.

Properties

Fallacinol is a member of the class of chemical compounds called

s. Its

IUPAC name In chemical nomenclature, a preferred IUPAC name (PIN) is a unique name, assigned to a chemical substance and preferred among all possible names generated by IUPAC nomenclature. The "preferred IUPAC nomenclature" provides a set of rules for choos ...

is 1,8-dihydroxy-3-hydroxymethyl-6-methoxyanthraquinone. The absorbance maxima (λ_max) of fallacinol in the ultraviolet spectrum has five peaks of maximum absorption at 223, 251, 266, 287

nanometre 330px, Different lengths as in respect to the Molecule">molecular scale. The nanometre (international spelling as used by the International Bureau of Weights and Measures; SI symbol: nm), or nanometer (American spelling), is a unit of length ...

s; the

visible spectrum The visible spectrum is the spectral band, band of the electromagnetic spectrum that is visual perception, visible to the human eye. Electromagnetic radiation in this range of wavelengths is called ''visible light'' (or simply light). The optica ...

has peaks at 434 and 455 nm. In the

infrared spectrum Infrared (IR; sometimes called infrared light) is electromagnetic radiation (EMR) with wavelengths longer than that of visible light but shorter than microwaves. The infrared spectral band begins with the waves that are just longer than those of ...

, it has peaks at 1624, 1631, 1670, 3450, 3520 cm⁻¹. Fallacinol's

is C₁₆H₁₂O₆; it has a

molecular mass The molecular mass () is the mass of a given molecule, often expressed in units of daltons (Da). Different molecules of the same compound may have different molecular masses because they contain different isotopes of an element. The derived quan ...

of 300.26

grams per mole In chemistry, the molar mass () (sometimes called molecular weight or formula weight, but see related quantities for usage) of a chemical substance ( element or compound) is defined as the ratio between the mass () and the amount of substance ...

. In its purified crystalline form, it exists as orange needles, with a melting point of . It is

soluble In chemistry, solubility is the ability of a substance, the solute, to form a solution with another substance, the solvent. Insolubility is the opposite property, the inability of the solute to form such a solution. The extent of the solubi ...

in cold dilute

potassium hydroxide Potassium hydroxide is an inorganic compound with the formula K OH, and is commonly called caustic potash. Along with sodium hydroxide (NaOH), KOH is a prototypical strong base. It has many industrial and niche applications, most of which utili ...

, forming red-violet crystals, and is insoluble in

sodium bicarbonate Sodium bicarbonate ( IUPAC name: sodium hydrogencarbonate), commonly known as baking soda or bicarbonate of soda (or simply “bicarb” especially in the UK) is a chemical compound with the formula NaHCO3. It is a salt composed of a sodium cat ...

and

carbonate A carbonate is a salt of carbonic acid, (), characterized by the presence of the carbonate ion, a polyatomic ion with the formula . The word "carbonate" may also refer to a carbonate ester, an organic compound containing the carbonate group ...

solutions. Similar to parietin, it produces a reddish-brown colour with alcoholic

ferric chloride Iron(III) chloride describes the inorganic compounds with the formula (H2O)x. Also called ferric chloride, these compounds are some of the most important and commonplace compounds of iron. They are available both in anhydrous and in hydrated f ...

and yields a deep orange-red solution with concentrated

sulfuric acid Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid (English in the Commonwealth of Nations, Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen, ...

, which appears

eosin Eosin is the name of several fluorescent acidic compounds which bind to and from salts with basic, or eosinophilic, compounds like proteins containing basic amino acid residues such as histidine, arginine and lysine, and stains them dark red ...

-like in thin layers. To early researchers, these properties suggested that fallacinol was structurally similar to parietin but with an additional oxygen atom, inferred to be a

hydroxyl group In chemistry, a hydroxy or hydroxyl group is a functional group with the chemical formula and composed of one oxygen atom covalently bonded to one hydrogen atom. In organic chemistry, alcohols and carboxylic acids contain one or more hydroxy ...

, based on its higher melting point and reduced solubility. The sparing solubility of its potassium salt and its insolubility in aqueous

sodium carbonate Sodium carbonate (also known as washing soda, soda ash, sal soda, and soda crystals) is the inorganic compound with the formula and its various hydrates. All forms are white, odourless, water-soluble salts that yield alkaline solutions in water ...

suggested a methoxyl group placement consistent with other known compounds like parietin and erythroglaucin. Like many anthraquinones, fallacinol can be reduced to its anthranol form, where one of the

quinone The quinones are a class of organic compounds that are formally "derived from aromatic compounds benzene.html" ;"title="uch as benzene">uch as benzene or naphthalene] by conversion of an even number of –CH= groups into –C(=O)– groups with ...

groups is converted to an alcohol group. This reduced form can be prepared by treating fallacinol with

zinc Zinc is a chemical element; it has symbol Zn and atomic number 30. It is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodic tabl ...

dust in boiling

acetic acid Acetic acid , systematically named ethanoic acid , is an acidic, colourless liquid and organic compound with the chemical formula (also written as , , or ). Vinegar is at least 4% acetic acid by volume, making acetic acid the main compone ...

, yielding lemon-yellow prismatic crystals with a melting point of 249–250 °C. The anthranol form shows distinct colour reactions, dissolving in cold concentrated sulfuric acid to give a golden yellow colour that changes to dark green after about an hour, and slowly dissolving in

sodium hydroxide Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula . It is a white solid ionic compound consisting of sodium cations and hydroxide anions . Sodium hydroxide is a highly corrosive base (chemistry), ...

to form a pink solution that eventually deposits violet-red crystals. The compound can be readily oxidised back to fallacinol using

chromic acid Chromic acid is a chemical compound with the chemical formula . It is also a jargon for a solution formed by the addition of sulfuric acid to aqueous solutions of dichromate. It consists at least in part of chromium trioxide. The term "chromic ...

, demonstrating the reversible nature of this reduction. Fallacinol was shown to have

antifungal An antifungal medication, also known as an antimycotic medication, is a pharmaceutical fungicide or fungistatic used to treat and prevent mycosis such as athlete's foot, ringworm, candidiasis (thrush), serious systemic infections such as ...

activity and

antibacterial 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 ...

activity in laboratory tests; it was particularly active against the fungus species ''

Trichoderma harzianum ''Trichoderma harzianum'' is a fungus that is also used as a fungicide. It is used for foliar application, seed treatment and soil treatment for suppression of fungal pathogens causing various fungal plant diseases. Commercial biotechnological ...

'', ''

Aspergillus niger ''Aspergillus niger'' is a mold classified within the ''Nigri'' section of the ''Aspergillus'' genus. The ''Aspergillus'' genus consists of common molds found throughout the environment within soil and water, on vegetation, in fecal matter, on de ...

'', and '' Penicillium verrucosum''. In a study exploring lichen compounds for COVID-19 therapeutics, fallacinol demonstrated the highest

binding energy In physics and chemistry, binding energy is the smallest amount of energy required to remove a particle from a system of particles or to disassemble a system of particles into individual parts. In the former meaning the term is predominantly use ...

against SARS-CoV-2's

spike protein In virology, a spike protein or peplomer protein is a protein that forms a large structure known as a spike or peplomer projecting from the surface of an viral envelope, enveloped virus. as cited in The proteins are usually glycoproteins that ...

, suggesting its potential as an inhibitor of virus growth.

Chemical synthesis

synthetic Synthetic may refer to: Science * Synthetic biology * Synthetic chemical or compound, produced by the process of chemical synthesis * Synthetic elements, chemical elements that are not naturally found on Earth and therefore have to be created in ...

route to fallacinol has been developed using parietin as an intermediate, highlighting a biogenetic link between the two compounds found in the lichen. The process involves the conversion of parietin di

acetate An acetate is a salt formed by the combination of acetic acid with a base (e.g. alkaline, earthy, metallic, nonmetallic, or radical base). "Acetate" also describes the conjugate base or ion (specifically, the negatively charged ion called ...

to an ω- bromo derivative via ''N''-bromosuccinimide in the presence of

benzoyl peroxide Benzoyl peroxide is a chemical compound (specifically, an organic peroxide) with structural formula , often abbreviated as (BzO)2. In terms of its structure, the molecule can be described as two benzoyl (, Bz) groups connected by a peroxide ...

, a technique also applied to various anthraquinones and related compounds. The brominated intermediate is then converted to fallacinol triacetate using

silver acetate Silver acetate is a coordination compound with the empirical formula CH3CO2Ag (or AgC2H3O2). A photosensitive, white, crystalline solid, it is a useful reagent in the laboratory as a source of silver ions lacking an oxidizing anion. Synthesis an ...

and

acetic anhydride Acetic anhydride, or ethanoic anhydride, is the chemical compound with the chemical formula, formula . Commonly abbreviated , it is one the simplest organic acid anhydride, anhydrides of a carboxylic acid and is widely used in the production of c ...

, yielding the target compound. Final steps include

with methanolic sulfuric acid to produce fallacinol and a

methylation Methylation, in the chemistry, chemical sciences, is the addition of a methyl group on a substrate (chemistry), substrate, or the substitution of an atom (or group) by a methyl group. Methylation is a form of alkylation, with a methyl group replac ...

stage for complete conversion. The synthesis not only mirrors the natural biogenesis but also achieves a

of , consistent with the purified natural product. An alternative synthesis was proposed in 1984, using a methodology employing Diels–Alder additions of napthoquinones to mixed trimethylsilyl vinylketene acetals as a route to synthetic hydroxyanthraquinones.

Occurrence

Fallacinol occurs in many species of the

, a large

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

of mostly

-forming

fungi A fungus (: fungi , , , or ; or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and mold (fungus), molds, as well as the more familiar mushrooms. These organisms are classified as one ...

. Historically, the substance was most associated with ''

Caloplaca ''Caloplaca'' is a lichen genus comprising a number of distinct species. Members of the genus are commonly called firedot lichen, jewel lichen.Field Guide to California Lichens, Stephen Sharnoff, Yale University Press, 2014, gold lichens, "ora ...

'', ''Teloschistes'', and '' Xanthoria'', but these genera have since been subdivided into many smaller,

monophyletic In biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of organisms which meets these criteria: # the grouping contains its own most recent co ...

genera. The cultivated mycobiont of ''Xanthoria fallax'', grown in isolation from its

green alga The green algae (: green alga) are a group of chlorophyll-containing autotrophic eukaryotes consisting of the phylum Prasinodermophyta and its unnamed sister group that contains the Chlorophyta and Charophyta/ Streptophyta. The land plants ( ...

l , does not produce fallacinol. Fallacinol is a common

secondary metabolite Secondary metabolites, also called ''specialised metabolites'', ''secondary products'', or ''natural products'', are organic compounds produced by any lifeform, e.g. bacteria, archaea, fungi, animals, or plants, which are not directly involved ...

in the lichen genus ''Teloschistes'', typically occurring in smaller amounts alongside parietin and other related compounds like fallacinal and

emodin Emodin (6-methyl-1,3,8-trihydroxyanthraquinone) is an organic compound. Classified as an anthraquinone, it can be isolated from rhubarb, buckthorn, and Japanese knotweed ('' Reynoutria japonica'' syn. ''Polygonum cuspidatum''). Emodin is part ...

. In 1970, Johan Santesson proposed a possible

biogenetic A biogenic substance is a product made by or of life forms. While the term originally was specific to metabolite compounds that had toxic effects on other organisms, it has developed to encompass any constituents, secretions, and metabolites of p ...

relationship between the anthraquinone compounds commonly found in ''

''. According to this scheme,

methylated Methylation, in the chemical sciences, is the addition of a methyl group on a substrate, or the substitution of an atom (or group) by a methyl group. Methylation is a form of alkylation, with a methyl group replacing a hydrogen atom. These term ...

to give

, which then undergoes three successive

oxidation Redox ( , , reduction–oxidation or oxidation–reduction) is a type of chemical reaction in which the oxidation states of the reactants change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is ...

s, sequentially forming fallacinol, fallacinal, and then parietinic acid. A chemosyndrome is set of

lichen product Lichen products, also known as lichen substances, are organic compounds produced by a lichen. Specifically, they are secondary metabolites. Lichen products are represented in several different chemical classes, including terpenoids, orcinol deri ...

s produced by a species, which typically includes one or more major compounds and a set of biosynthetically related minor compounds. In 2002, Ulrik Søchting and Patrik Frödén identified chemosyndrome A, the most common chemosyndrome in the genus '' Teloschistes'' and in the entire family Teloschistaceae, which features parietin as the main substance with smaller proportions of fallacinol, fallacinal, parietinic acid, and emodin. Fallacinol has been reported from the bushy shrub plant '' Senna didymobotrya'', widespread in eastern and central Africa, as well as from ''

Reynoutria japonica ''Reynoutria japonica'', synonyms ''Fallopia japonica'' and ''Polygonum cuspidatum'', is a species of herbaceous perennial plant in the knotweed and buckwheat family Polygonaceae. Common names include Japanese knotweed and Asian knotweed. It is ...

'', a plant in the knotweed family. The substance has been isolated from a culture of the

marine sponge Sponges or sea sponges are primarily marine invertebrates of the animal phylum Porifera (; meaning 'pore bearer'), a basal clade and a sister taxon of the diploblasts. They are sessile filter feeders that are bound to the seabed, and are on ...

-associated fungus '' Talaromyces stipitatus'', and from '' Dermocybe'' mushrooms, and has been detected chromatographically in extracts from several ''

Cortinarius ''Cortinarius'' is a globally distributed genus of fungus in the family Cortinariaceae. Its members are commonly known by the names cortinar and webcap. It is suspected to be the largest genus of agarics, containing over 2,000 widespread species ...

'' mushroom species.

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