Lichenology
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Lichenology is the branch of
mycology Mycology is the branch of biology concerned with the study of fungus, fungi, including their Taxonomy (biology), taxonomy, genetics, biochemistry, biochemical properties, and ethnomycology, use by humans. Fungi can be a source of tinder, Edible ...
that studies the
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,
symbiotic Symbiosis (Ancient Greek : living with, companionship < : together; and ''bíōsis'': living) is any type of a close and long-term biolo ...
organism An organism is any life, living thing that functions as an individual. Such a definition raises more problems than it solves, not least because the concept of an individual is also difficult. Many criteria, few of them widely accepted, have be ...
s made up of an intimate symbiotic association of a microscopic
alga Algae ( , ; : alga ) is an informal term for any organisms of a large and diverse group of photosynthetic organisms that are not plants, and includes species from multiple distinct clades. Such organisms range from unicellular microalgae, suc ...
(or a
cyanobacterium Cyanobacteria ( ) are a group of autotrophic gram-negative bacteria that can obtain biological energy via oxygenic photosynthesis. The name "cyanobacteria" () refers to their bluish green (cyan) color, which forms the basis of cyanobacteria' ...
) with a
filament The word filament, which is descended from Latin ''filum'' meaning " thread", is used in English for a variety of thread-like structures, including: Astronomy * Galaxy filament, the largest known cosmic structures in the universe * Solar filament ...
ous
fungus 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 ...
. Lichens are chiefly characterized by this symbiosis. Study of lichens draws knowledge from several disciplines:
mycology Mycology is the branch of biology concerned with the study of fungus, fungi, including their Taxonomy (biology), taxonomy, genetics, biochemistry, biochemical properties, and ethnomycology, use by humans. Fungi can be a source of tinder, Edible ...
, phycology,
microbiology Microbiology () is the branches of science, scientific study of microorganisms, those being of unicellular organism, unicellular (single-celled), multicellular organism, multicellular (consisting of complex cells), or non-cellular life, acellula ...
and
botany Botany, also called plant science, is the branch of natural science and biology studying plants, especially Plant anatomy, their anatomy, Plant taxonomy, taxonomy, and Plant ecology, ecology. A botanist or plant scientist is a scientist who s ...
. Scholars of lichenology are known as lichenologists. Study of lichens is conducted by both
professional A professional is a member of a profession or any person who work (human activity), works in a specified professional activity. The term also describes the standards of education and training that prepare members of the profession with the partic ...
and
amateur An amateur () is generally considered a person who pursues an avocation independent from their source of income. Amateurs and their pursuits are also described as popular, informal, autodidacticism, self-taught, user-generated, do it yourself, DI ...
lichenologists. Methods for species identification include reference to single-access keys on lichens. An example reference work is ''Lichens of North America'' (2001) by Irwin M. Brodo, Sylvia Sharnoff and Stephen Sharnoff and that book's 2016 expansion, ''Keys to Lichens of North America: Revised and Expanded'' by the same three authors joined by Susan Laurie-Bourque. A chemical spot test can be used to detect the presence of certain lichen products which can be characteristic of a given lichen
species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...
. Some components of certain lichens may also
fluoresce 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 color ...
under
ultraviolet light Ultraviolet radiation, also known as simply UV, is electromagnetic radiation of wavelengths of 10–400 nanometers, shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight and constitutes about 10% of th ...
, providing another form of lichen identification test. Lichenologists may also study the growth and growth rate of lichens,
lichenometry In archaeology, palaeontology, and geomorphology, lichenometry is a geomorphic method of geochronologic dating that uses lichen growth to determine the age of exposed rock, based on a presumed specific rate of increase in radial size over time ...
, the role of lichens in nutrient cycling, the ecological role of lichens in biological soil crusts, the morphology of lichens, their anatomy and physiology, and ethnolichenology topics including the study of edible lichens. As with any other field of study, lichenology has its own set of rules for taxonomic
nomenclature Nomenclature (, ) is a system of names or terms, or the rules for forming these terms in a particular field of arts or sciences. (The theoretical field studying nomenclature is sometimes referred to as ''onymology'' or ''taxonymy'' ). The principl ...
and its own set of other terminology.


History


The beginnings

Lichens as a group have received less attention in classical treatises on botany than other groups although the relationship between humans and some species has been documented from early times. Several species have appeared in the works of
Dioscorides Pedanius Dioscorides (, ; 40–90 AD), "the father of pharmacognosy", was a Greek physician, pharmacologist, botanist, and author of (in the original , , both meaning "On Materia medica, Medical Material") , a 5-volume Greek encyclopedic phar ...
,
Pliny the Elder Gaius Plinius Secundus (AD 23/24 79), known in English as Pliny the Elder ( ), was a Roman Empire, Roman author, Natural history, naturalist, and naval and army commander of the early Roman Empire, and a friend of the Roman emperor, emperor Vesp ...
and
Theophrastus Theophrastus (; ; c. 371 – c. 287 BC) was an ancient Greek Philosophy, philosopher and Natural history, naturalist. A native of Eresos in Lesbos, he was Aristotle's close colleague and successor as head of the Lyceum (classical), Lyceum, the ...
although the studies are not very deep. During the first centuries of the modern age they were usually put forward as examples of
spontaneous generation Spontaneous generation is a superseded scientific theory that held that living creatures could arise from non-living matter and that such processes were commonplace and regular. It was hypothesized that certain forms, such as fleas, could ...
and their reproductive mechanisms were totally ignored. For centuries naturalists had included lichens in diverse groups until in the early 18th century a French researcher
Joseph Pitton de Tournefort Joseph Pitton de Tournefort (5 June 165628 December 1708) was a French botanist, notable as the first to make a clear definition of the concept of genus for plants. Botanist Charles Plumier was his pupil and accompanied him on his voyages. Li ...
in his ''Institutiones Rei Herbariae'' grouped them into their own genus. He adopted the Latin term lichen, which had already been used by Pliny who had imported it from Theophrastus but up until then this term had not been widely employed. The original meaning of the Greek word λειχήν (leichen) was moss that in its turn derives from the Greek verb λείχω (liekho) to suck because of the great ability of these organisms to absorb water. In its original use the term signified
mosses Mosses are small, non-vascular flowerless plants in the taxonomic division Bryophyta (, ) '' sensu stricto''. Bryophyta ('' sensu lato'', Schimp. 1879) may also refer to the parent group bryophytes, which comprise liverworts, mosses, and ho ...
,
liverworts Liverworts are a group of non-vascular plant, non-vascular embryophyte, land plants forming the division Marchantiophyta (). They may also be referred to as hepatics. Like mosses and hornworts, they have a gametophyte-dominant life cycle, in wh ...
as well as
lichens 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 ...
. Some forty years later Dillenius in his ''Historia Muscorum'' made the first division of the group created by Tournefort separating the sub-families Usnea, Coralloides and
Lichens 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 ...
in response to the morphological characteristics of the lichen
thallus Thallus (: thalli), from Latinized Greek (), meaning "a green shoot" or "twig", is the vegetative tissue of some organisms in diverse groups such as algae, fungi, some liverworts, lichens, and the Myxogastria. A thallus usually names the entir ...
. After the revolution in
taxonomy image:Hierarchical clustering diagram.png, 280px, Generalized scheme of taxonomy Taxonomy is a practice and science concerned with classification or categorization. Typically, there are two parts to it: the development of an underlying scheme o ...
brought in by
Linnaeus Carl Linnaeus (23 May 1707 – 10 January 1778), also known after ennoblement in 1761 as Carl von Linné,#Blunt, Blunt (2004), p. 171. was a Swedish biologist and physician who formalised binomial nomenclature, the modern system of naming o ...
and his new system of classification lichens are retained in the
Plant Plants are the eukaryotes that form the Kingdom (biology), kingdom Plantae; they are predominantly Photosynthesis, photosynthetic. This means that they obtain their energy from sunlight, using chloroplasts derived from endosymbiosis with c ...
Kingdom forming a single group
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 ...
with eight divisions within the group according to the morphology of the
thallus Thallus (: thalli), from Latinized Greek (), meaning "a green shoot" or "twig", is the vegetative tissue of some organisms in diverse groups such as algae, fungi, some liverworts, lichens, and the Myxogastria. A thallus usually names the entir ...
. The
taxonomy image:Hierarchical clustering diagram.png, 280px, Generalized scheme of taxonomy Taxonomy is a practice and science concerned with classification or categorization. Typically, there are two parts to it: the development of an underlying scheme o ...
of lichens was first intensively investigated by the Swedish botanist
Erik Acharius Erik Acharius (10 October 1757 – 14 August 1819) was a Swedish botanist who pioneered the Taxonomy (biology), taxonomy of lichens and is known as the "father of lichenology". Acharius was famously the last pupil of Carl Linnaeus. Life Ac ...
(1757–1819), who is therefore sometimes named the "father of lichenology". Acharius was a student of
Carl Linnaeus Carl Linnaeus (23 May 1707 – 10 January 1778), also known after ennoblement in 1761 as Carl von Linné,#Blunt, Blunt (2004), p. 171. was a Swedish biologist and physician who formalised binomial nomenclature, the modern system of naming o ...
. Some of his more important works on the subject, which marked the beginning of lichenology as a discipline, are: * ''Lichenographiae Suecia prodromus'' (1798) * ''Methodus lichenum'' (1803) * ''Lichenographia universalis'' (1810) * ''Synopsis methodica lichenum'' (1814) Later lichenologists include the American scientists Vernon Ahmadjian and Edward Tuckerman and the
Russia Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...
n
evolutionary biologist Evolutionary biology is the subfield of biology that studies the evolutionary processes such as natural selection, common descent, and speciation that produced the diversity of life on Earth. In the 1930s, the discipline of evolutionary biol ...
Konstantin Merezhkovsky, as well as amateurs such as Louisa Collings. Over the years research shed new light into the nature of these organisms still classified as plants. A controversial issue surrounding lichens since the early 19th century is their reproduction. In these years a group of researchers faithful to the tenets of Linnaeus considered that lichens reproduced sexually and had sexual reproductive organs, as in other plants, independent of whether asexual reproduction also occurred. Other researchers only considered asexual reproduction by means of Propagules.


19th century

Against this background appeared the Swedish botanist
Erik Acharius Erik Acharius (10 October 1757 – 14 August 1819) was a Swedish botanist who pioneered the Taxonomy (biology), taxonomy of lichens and is known as the "father of lichenology". Acharius was famously the last pupil of Carl Linnaeus. Life Ac ...
disciple of Linnaeus, who is today considered the father of lichenology, starting the taxonomy of lichens with his pioneering study of Swedish lichens in Lichenographiae Suecicae Prodromus of 1798 or in his Synopsis Methodica Lichenum, Sistens omnes hujus Ordinis Naturalis of 1814. These studies and classifications are the cornerstone of subsequent investigations. In these early years of structuring the new discipline various works of outstanding scientific importance appeared such as Lichenographia Europaea Reformata published in 1831 by
Elias Fries Elias Magnus Fries (15 August 1794 – 8 February 1878) was a Swedish mycologist and botanist. He is sometimes called the "Linnaeus of Mycology". In his works he described and assigned botanical names to hundreds of fungus and lichen sp ...
or Enumeratio Critico Lichenum Europaeorum 1850 by Ludwig Schaerer in Germany. But these works suffer from being superficial and mere lists of species without further physiological studies. It took until the middle of the 19th century for research to catch up using biochemical and physiological methods. In Germany and Johann Bayrhoffer, in France
Edmond Tulasne Louis René Étienne Tulasne, a.k.a. Edmond Tulasne (12 September 1815 – 22 December 1885) was a French botanist and mycologist born in Azay-le-Rideau. He originally studied law at Poitiers, but his interest later turned to botany. As a youn ...
and
Camille Montagne Jean Pierre François Camille Montagne (15 February 1784 – 5 December 1866) was a French people, French military physician and botanist who specialized in the fields of bryology and mycology. Life Montague was born in the commune of Vaudoy i ...
, in Russia Fedor Buhse, in England William Allport Leighton and in the United States Edward Tuckerman began to publish works of great scientific importance. Scientific publications settled many unknown facts about lichens. In the French publication Annales des Sciences Naturelles in an article of 1852 "Memorie pour servir a l'Histoire des Lichens Organographique et Physiologique" by
Edmond Tulasne Louis René Étienne Tulasne, a.k.a. Edmond Tulasne (12 September 1815 – 22 December 1885) was a French botanist and mycologist born in Azay-le-Rideau. He originally studied law at Poitiers, but his interest later turned to botany. As a youn ...
, the reproductive organs or apothecia of lichens was identified. These new discoveries were becoming increasingly contradictory for scientists. The apothecium reproductive organ being unique to
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 ...
but absent in other
photosynthetic Photosynthesis ( ) is a Biological system, system of biological processes by which Photoautotrophism, photosynthetic organisms, such as most plants, algae, and cyanobacteria, convert light energy, typically from sunlight, into the chemical ener ...
organisms. With improvements in
microscopy Microscopy is the technical field of using microscopes to view subjects too small to be seen with the naked eye (objects that are not within the resolution range of the normal eye). There are three well-known branches of microscopy: optical mic ...
,
algae Algae ( , ; : alga ) is an informal term for any organisms of a large and diverse group of photosynthesis, photosynthetic organisms that are not plants, and includes species from multiple distinct clades. Such organisms range from unicellular ...
were identified in the lichen structure, which heightened the contradictions. At first the presence of algae was taken as being due to contamination due to collection of samples in damp conditions and they were not considered as being in a
symbiotic Symbiosis (Ancient Greek : living with, companionship < : together; and ''bíōsis'': living) is any type of a close and long-term biolo ...
relation with the fungal part of the thallus. That the algae continued to multiply showed that they were not mere contaminants. It was Anton de Bary a German
mycologist Mycology is the branch of biology concerned with the study of fungi, including their taxonomy, genetics, biochemical properties, and use by humans. Fungi can be a source of tinder, food, traditional medicine, as well as entheogens, poison, and ...
who specialised in
phytopathology Plant pathology or phytopathology is the scientific study of plant diseases caused by pathogens (infectious organisms) and environmental conditions (physiological factors). Plant pathology involves the study of pathogen identification, disease ...
who first suggested in 1865 that lichens were merely the result of parasitism of various fungi of the
ascomycetes Ascomycota is a phylum of the kingdom Fungi that, together with the Basidiomycota, forms the subkingdom Dikarya. Its members are commonly known as the sac fungi or ascomycetes. It is the largest phylum of Fungi, with over 64,000 species. The de ...
group by
nostoc ''Nostoc'', also known as star jelly, troll's butter, spit of moon, fallen star, witch's butter (not to be confused with the fungi commonly known as witches' butter), and witch's jelly, is the most common genus of cyanobacteria found in a variety ...
type algae and others. Successive studies such as those carried out by Andrei Famintsyn and Baranetzky in 1867 showed no dependence of the algal component upon the lichen thallus and that the algal component could live independently of the thallus. It was in 1869 that Simon Schwendener demonstrated that all lichens were the result of fungal attack on the cells of algal cells and that all these algae also exist free in nature. This researcher was the first to recognise the dual nature of lichens as a result of the capture of the algal component by the fungal component. In 1873 Jean-Baptiste Edouard Bornet concluded form studying many different lichen species that the relationship between fungi and algae was purely
symbiotic Symbiosis (Ancient Greek : living with, companionship < : together; and ''bíōsis'': living) is any type of a close and long-term biolo ...
. It was also established that algae could associate with many different fungi to form different lichen
phenotypes In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology (physical form and structure), its developmental processes, its biochemical and physiological properti ...
.


20th century

In 1909 the Russian lichenologist Konstantin Mereschkowski presented a research paper "The Theory of two Plasms as the basis of
Symbiogenesis Symbiogenesis (endosymbiotic theory, or serial endosymbiotic theory) is the leading evolutionary theory of the origin of eukaryotic cells from prokaryotic organisms. The theory holds that mitochondria, plastids such as chloroplasts, and possibl ...
, A new study on the Origin of Organisms", which aims to explain a new theory of Symbiogenesis by lichens and other organisms as evidenced by his earlier work "Nature and Origin of Chromatophores in the Plant Kingdom". These new ideas can be studied today under the title of the Theory of
Endosymbiosis An endosymbiont or endobiont is an organism that lives within the body or cells of another organism. Typically the two organisms are in a mutualism (biology), mutualistic relationship. Examples are nitrogen-fixing bacteria (called rhizobia), whi ...
. Despite the above studies the dual nature of lichens remained no more than a theory until in 1939 the Swiss researcher Eugen A Thomas was able to reproduce in the laboratory the phenotype of the lichen '' Cladonia pyxidata'' by combining its two identified components. During the 20th century botany and mycology were still attempting to solve the two main problems surrounding lichens. On the one hand the definition of lichens and the relationship between the two symbionts and the taxonomic position of these organisms within the plant and fungal kingdoms. There appeared numerous renowned researchers within the field of lichenology such as Henry Nicollon des Abbayes, William Alfred Weber, Antonina Georgievna Borissova, Irwin M. Brodo, and George Albert Llano. Lichenology has found applications beyond
biology Biology is the scientific study of life and living organisms. It is a broad natural science that encompasses a wide range of fields and unifying principles that explain the structure, function, growth, History of life, origin, evolution, and ...
itself in the field of
geology Geology (). is a branch of natural science concerned with the Earth and other astronomical objects, the rocks of which they are composed, and the processes by which they change over time. Modern geology significantly overlaps all other Earth ...
in a technique known as
lichenometry In archaeology, palaeontology, and geomorphology, lichenometry is a geomorphic method of geochronologic dating that uses lichen growth to determine the age of exposed rock, based on a presumed specific rate of increase in radial size over time ...
where the age of an exposed surface can be found by studying the age of lichens growing on them. Age dating in this way can be absolute or relative because the growth of these organisms can be arrested under various conditions. The technique provides an average age of the older individual lichens providing a minimum age of the medium being studied. Lichenometry relies upon the fact that the maximum diameter of the largest thallus of an epilithic lichen growing on a substrate is directly proportional to the time from first exposure of the area to the environment as seen in studies by Roland Beschel in 1950 and is especially useful in areas exposed for less than 1000 years. Growth is greatest in the first 20 to 100 years with 15–50 mm growth per year and less in the following years with average growth of 2–4 mm per year. The difficulty of giving a definition applicable to every known lichen has been debated since lichenologists first recognised the dual nature of lichens. In 1982 the International Association for Lichenology convened a meeting to adopt a single definition of lichen drawing on the proposals of a committee. The chairman of this committee was the renowned researcher Vernon Ahmadjian. The definition finally adopted was that lichen could be considered as the association between a fungus and a photosynthetic symbiont resulting in a thallus of specific structure.David L. Hawksworth (1989) "Interactions Fungus and Alga in Lichen Symbiosis liquenoides" ''Annals of the Botanical Garden of Madrid'' (46). Such a simple
a priori ('from the earlier') and ('from the later') are Latin phrases used in philosophy to distinguish types of knowledge, Justification (epistemology), justification, or argument by their reliance on experience. knowledge is independent from any ...
definition soon brought criticism from various lichenologists and there soon emerged reviews and suggestions for amendments. For example, David L. Hawksworth considered the definition imperfect because it is impossible to determine which one thallus is of a specific structure since thalli changed depending upon the substrate and conditions in which they developed. This researcher represents one of the main trends among lichenologists who consider it impossible to give a single definition to lichens since they are a unique type of organism. Today studies in lichenology are not restricted to the description and taxonomy of lichens but have application in various scientific fields. Especially important are studies on
environmental quality Environmental quality is considered by scientists and environmentalists as the properties and attributes of the environment, generalized or on a small scale, as they affect human beings and other organisms. It is a measure of the condition of an e ...
that are made through the interaction of lichens with their environment. Lichen is extremely sensitive to various air pollutants, especially to
sulphur dioxide Sulfur dioxide (IUPAC-recommended spelling) or sulphur dioxide (traditional Commonwealth English) is the chemical compound with the formula . It is a colorless gas with a pungent smell that is responsible for the odor of burnt matches. It is r ...
, which causes
acid rain Acid rain is rain or any other form of Precipitation (meteorology), precipitation that is unusually acidic, meaning that it has elevated levels of hydrogen ions (low pH). Most water, including drinking water, has a neutral pH that exists b ...
and prevents water absorption.


Lichens in pharmacology

Although several species of lichen have been used in
traditional medicine Traditional medicine (also known as indigenous medicine or folk medicine) refers to the knowledge, skills, and practices rooted in the cultural beliefs of various societies, especially Indigenous groups, used for maintaining health and treatin ...
it was not until the early 20th century that modern science became interested in them. The discovery of various substances with
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 ...
action in lichen thalli was essential for scientists to become aware of the possible importance of these organisms to
medicine Medicine is the science and Praxis (process), practice of caring for patients, managing the Medical diagnosis, diagnosis, prognosis, Preventive medicine, prevention, therapy, treatment, Palliative care, palliation of their injury or disease, ...
. From the 1940s there appeared various works by the noted
microbiologist A microbiologist (from Greek ) is a scientist who studies microscopic life forms and processes. This includes study of the growth, interactions and characteristics of microscopic organisms such as bacteria, algae, fungi, and some types of par ...
Rufus Paul Burkholder who demonstrated antibacterial action of lichens of the genus '' Usnea'' against ''
Bacillus subtilis ''Bacillus subtilis'' (), known also as the hay bacillus or grass bacillus, is a gram-positive, catalase-positive bacterium, found in soil and the gastrointestinal tract of ruminants, humans and marine sponges. As a member of the genus ''Bacill ...
'' and '' Sarcina lutea''. Studies showed that the substance that inhibited growth of bacteria was usnic acid. Something similar occurred with the substance Ramelina synthesised by the lichen '' Ramalina reticulata'', nevertheless, these substances proved ineffective against
Gram negative bacteria Gram-negative bacteria are bacteria that, unlike gram-positive bacteria, do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. Their defining characteristic is that their cell envelope consists of ...
such as ''
Escherichia coli ''Escherichia coli'' ( )Wells, J. C. (2000) Longman Pronunciation Dictionary. Harlow ngland Pearson Education Ltd. is a gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus '' Escherichia'' that is commonly fo ...
'' and ''
Pseudomonas ''Pseudomonas'' is a genus of Gram-negative bacteria belonging to the family Pseudomonadaceae in the class Gammaproteobacteria. The 348 members of the genus demonstrate a great deal of metabolic diversity and consequently are able to colonize a ...
''. With these investigations the number of antibacterial substances and possible drug targets known to be produced by lichens increased
ergosterol Ergosterol (ergosta-5,7,22-trien-3β-ol) is a mycosterol found in cell membranes of fungi and protozoa, serving many of the same functions that cholesterol serves in animal cells. Because many fungi and protozoa cannot survive without ergostero ...
, usnic acid etc. Interest in the potential of substances synthesised by lichens increased with the end of
World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...
along with the growing interest in all
antibiotic An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting pathogenic bacteria, bacterial infections, and antibiotic medications are widely used in the therapy ...
substances. In 1947 antibacterial action was identified in extracts of '' Cetraria islandica'' and the compounds identified as responsible for bacterial inhibition were shown to be d-protolichosteric acid and d-1-usnic acid. Further investigations have identified novel antibacterial substances, Alectosarmentin or Atranorin. Antibacterial action of substances produced by lichens is related to their ability to disrupt bacterial
proteins Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, re ...
with a subsequent loss of bacterial
metabolic Metabolism (, from ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cellular processes; the ...
capacity. This is possible due to the action of lichen
phenol Phenol (also known as carbolic acid, phenolic acid, or benzenol) is an aromatic organic compound with the molecular formula . It is a white crystalline solid that is volatile and can catch fire. The molecule consists of a phenyl group () ...
ics such as usnic acid derivatives. From the 1950s the lichen product usnic acid was the object of most antitumour research. These studies revealed some
in vitro ''In vitro'' (meaning ''in glass'', or ''in the glass'') Research, studies are performed with Cell (biology), cells or biological molecules outside their normal biological context. Colloquially called "test-tube experiments", these studies in ...
antitumour activity by substances identified in two common lichens '' Peltigera leucophlebia'' and '' Collema flaccidum''. Recent work in the field of applied
biochemistry Biochemistry, or biological chemistry, is the study of chemical processes within and relating to living organisms. A sub-discipline of both chemistry and biology, biochemistry may be divided into three fields: structural biology, enzymology, a ...
has shown some antiviral activity with some lichen substances. In 1989 K Hirabayashi presented his investigations on inhibitory lichen polysaccharides in HIV infection.


Bibliography

*"Protocols in Lichenology: Culturing, Biochemistry, Ecophysiology and Use in Biomonitoring" (Springer Lab Manuals, Kraner, Ilse, Beckett, Richard and Varma, Ajit (28 Nov 2001) *''Lichenology in the British Isles, 1568–1975: An Historical and Biographical Survey'', D. L. Hawksworth and M. R. D. Seaward (Dec 1977) *"Lichenology: Progress and Problems" (Special Volumes/Systematics Association) Denis Hunter Brown et al. (10 May 1976) *''Lichenology in Indian Subcontinent'', Dharani Dhar Awasthi (1 Jan 2000) *''Lichenology in Indian Subcontinent 1966–1977'', Ajay Singh (1980) *''CRC Handbook of Lichenology'', Volume II: v.2, Margalith Galun (30 Sep 1988) *''A Textbook of General Lichenology'', Albert Schneider (24 May 2013) *''Horizons in Lichenology'' D. H. Dalby (1988) *''Bibliography of Irish Lichenology'', M. E. Mitchell (Nov 1972) *''Diccionario de Liquenologia/Dictionary of Lichenology'', Kenneth Allen Hornak (1998) *"Progress and Problems in Lichenology in the Eighties: Proceedings" (''Bibliotheca Lichenologica''), Elisabeth Peveling (1987) *''A Textbook of General Lichenology with Descriptions and Figures of the Genera Occurring in the North Eastern United States'', Albert Schneider (Mar 2010) *''The Present Status and Potentialities of the Lichenology in China'', Liu Hua Jie (1 Jan 2000) *''Lichens to Biomonitor the Environment'', Shukla, D. K. Vertika, Upreti and Bajpai, Rajesh (Aug 2013) *''Lichenology and Bryology in the Galapagos Islands with Checklists of the Lichens and Bryophytes thus far Reported'', William A. Weber (1966) *''Flechten Follmann: Contributions to Lichenology in Honour of Gerhard Follmann'', Gerhard Follmann, F. J. A. Daniels, Margot Schultz and Jorge Peine (1995) *''Environmental Lichenology: Biomonitoring Trace Element Air Pollution'', Joyce E. Sloof (1993) *''The Journal of the Hattori Botanical Laboratory: Devoted to Bryology and Lichenology'', Zennosuke Iwatsuki (1983) *''Contemporary Lichenology and Lichens of Western Oregon'', W. Clayton Fraser (1968) *''Irish Lichenology 1858–1880: Selected Letters of Isaac Carroll, Theobald Jones, Charles Larbalestier'' (1996) *''Lichens from West of Hudson's Bay'' (''Lichens of Arctic America'' Vol. 1), John W. Thompson (1953) *''Les Lichens - Morphologie, Biologie, Systematique'', Fernand Moreau (1927) *"Eric Acharius and his Influence on English Lichenology" (''Botany Bulletins''), David J. Galloway (Jul 1988) *"Lichenographia Thompsoniana: North American Lichenology in Honour of John W. Thompson", M. G. Gleen (May 1998) *"Monitoring with Lichens-Proceedings of the NATO Advanced Research Workshop", Nimis, Pier Luigi, Scheidegger, Christoph and Wolseley, Patricia (Dec 2001) *''Contributions to Lichenology: In Honour of A. Henssen'', H. M. Jahns and A. Henssen (1990) *''Studies in Lichenology with Emphasis on Chemotaxonomy, Geography and Phytochemistry'': Festschrift Christian Leuckert, Johannes Gunther Knoph, Kunigunda Schrufer and Harry J. M. Sipman (1995) *''Swedish Lichenology: Dedicated to Roland Moberg'', Jan Erik Mattsson, Mats Wedin and Inga Hedberg (Sep 1999) *''Index of Collectors in Knowles the Lichens of Ireland (1929) and Porter's Supplement: with a Conspectus of Lichen'', M. E. Mitchell, Matilda C. Knowles and Lilian Porter (1998) *''Biodeterioration of Stone Surfaces: Lichens and Biofilms as Weathering Agents of Rocks and Cultural Heritage'', Larry St. Clair and Mark Seaward (Oct 2011) *''The Lichen Symbiosis'', Vernon Ahmadjian (Aug 1993) *''Lichen Biology'', Thomas H. Nash (Jan 2008) *''Fortschritte der Chemie organischer Naturstoffe/ Progress in the Chemistry of Organic Natural Products'', S. Hunek (Oct 2013)


Notable lichenologists


Lichenology organizations

* British Lichen Society *
American Bryological and Lichenological Society The American Bryological and Lichenological Society is an organization devoted to the scientific study of all aspects of the biology of bryophytes and lichen-forming fungi and is one of the nation's oldest botanical organizations. It was original ...
* International Association for Lichenology


Lichen collections

* British Lichen Society * Botanische Staatssammlung München *
Canadian Museum of Nature The Canadian Museum of Nature (; CMN) is a national museums of Canada, national natural history museum based in Canada's National Capital Region (Canada), National Capital Region. The museum's exhibitions and public programs are housed in the Vi ...
* Centraalbureau voor Schimmelcultures * National Botanical Research Institute (CSIR), India *
Iowa State University Iowa State University of Science and Technology (Iowa State University, Iowa State, or ISU) is a Public university, public land-grant university, land-grant research university in Ames, Iowa, United States. Founded in 1858 as the Iowa Agricult ...
, Ada Hayden Herbarium,
Ames, Iowa Ames () is a city in Story County, Iowa, United States, located approximately north of Des Moines, Iowa, Des Moines in central Iowa. It is the home of Iowa State University (ISU). According to the 2020 United States census, 2020 census, Ames ha ...
* National Museum Cardiff *
Natural History Museum, London The Natural History Museum in London is a museum that exhibits a vast range of specimens from various segments of natural history. It is one of three major museums on Exhibition Road in South Kensington, the others being the Science Museum (Lo ...
*
New York Botanical Garden The New York Botanical Garden (NYBG) is a botanical garden at Bronx Park in the Bronx, New York City. Established in 1891, it is located on a site that contains a landscape with over one million living plants; the Enid A. Haupt Conservatory, ...
* Royal Botanic Garden, Edinburgh *
Royal Botanic Gardens, Kew Royal Botanic Gardens, Kew is a non-departmental public body in the United Kingdom sponsored by the Department for Environment, Food and Rural Affairs. An internationally important botanical research and education institution, it employs 1,10 ...
, London * University of Michigan Herbarium,
Ann Arbor, Michigan Ann Arbor is a city in Washtenaw County, Michigan, United States, and its county seat. The 2020 United States census, 2020 census recorded its population to be 123,851, making it the List of municipalities in Michigan, fifth-most populous cit ...
*
University of Wisconsin-Madison A university () is an institution of tertiary education and research which awards academic degrees in several academic disciplines. ''University'' is derived from the Latin phrase , which roughly means "community of teachers and scholars". Uni ...
Herbarium,
Madison, Wisconsin Madison is the List of capitals in the United States, capital city of the U.S. state of Wisconsin. It is the List of municipalities in Wisconsin by population, second-most populous city in the state, with a population of 269,840 at the 2020 Uni ...
* Ulster Museum, Belfast


See also

* Outline of lichens * Acharius Medal, an award in lichenology


Footnotes


References


External links


American Bryological and Lichenological SocietyBelgium, Luxembourg and Northern France, Lichens ofBritish Lichen SocietyCentral European Bryological and Lichenological Society (Ger)Czech Bryological and Lichenological Society (Cze)Guide to using a Lichen-Based Index to Assess Nitrogen Air Quality
* ttp://www.lichenology.org/ International Association for Lichenologybr>Irish Lichens

Italian Lichenological Society (Ita)Japanese Lichenological Society (Eng)Lichenological Resources (Rus)Lichenland Oregon State UniversityLichens of Ireland Project

LichenPortal.org - The Consortium of Lichen HerbariaMicroscopy of Lichens (Ger)Netherlands Bryological and Lichenological Society (nl)National Biodiversity GatewayNordic Lichen Society (Eng)North American LichensPaleo-Lichenology (Ger)Scottish LichensSwedish Lichens Lief & Anita StridvallTropical Lichens
* {{Authority control Branches of biology Branches of mycology Fungi and humans Mycology