Lichens

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  Chemistry, Biology and Pharmacology of Lichen

  • Ashoke Kumar Das, Ajay Sharma, Deepika Kathuria, Mohammad Javed Ansari, Garima Bhardwaj(Authors)
  • 2024(Publication Date)
  • Wiley

    (Publisher)

  1 Chemistry, Biology and Pharmacology of Lichen, First Edition. Edited by Ashoke Kumar Das, Ajay Sharma, Deepika Kathuria, Mohammad Javed Ansari, and Garima Bhardwaj. © 2024 John Wiley & Sons Ltd. Published 2024 by John Wiley & Sons Ltd. Overview of Lichen Ashoke Kumar Das 1 , Subrata Sarkar 1 , and Papori Devi 2 1 Department of Botany, Abhayapuri College, Abhayapuri, Assam, India 2 Department of Botany, Arya Vidyapeeth College, Guwahati, Assam, India 1.1 Introduction The term “lichen” was coined by Theophrastus (Father of Botany) more than two thousand years ago. Till the 19th century, Lichens were thought to be individually recognized organ- isms. In 1869, only it was accepted that it was composed of two different organisms [1, 2]. Lichens are composed of different species of fungi (Mycobiont), algae, or cyanobacteria (Photobiont) [3–9], and some microorganisms like bacteria are also associated with them [10–14]. There is a long debate and study regarding the combination of association of different components of lichen symbiosis and their physiology [15–17]. Though lichen is composed of different components, they form morphologically constant forms that are des- ignated as species [18]. They are frequently specified as the best example of mutualistic partnerships. Photobionts have the capacity to photosynthesize; they provide carbohy- drates to the fungal partner, and the mycobiont creates a physical scaffold that encloses and supports the growth of photobionts [5]. According to Hawksworth, “a lichen is a stable self-supporting association of a mycobiont and a photobiont in which mycobiont is the exhabitant” [4]. Through a process called lichenization, a fungus and a photosynthetic partner transformed into a lichen thallus, from a free-living to a symbiotic state [19]. Lichens are distributed throughout the world and found to grow in almost all climatic conditions (“Lichens,” [20]).

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  Metals in the Environment

  Analysis by Biodiversity

  • M.N.V. Prasad(Author)
  • 2001(Publication Date)
  • CRC Press

    (Publisher)

  5 Lichens Cristina Branquinho Universidade Atlantica, Oeiras, Portugal 1 INTRODUCTION 1.1 Understanding the Singularity of Lichens Lichens are by definition symbiotic organisms composed of a fungal partner, the mycobiont, and one or more photosynthetic partners, the photobiont, which may be either a green alga or a cyanobacterium (1). The nature of the lichen symbiosis is still not totally clear: although most authors consider Lichens to be a classic example of mutualism, in which all partners gain benefits from association, others suggest that Lichens are an example of controlled parasitism (1). The degree of lichenization varies significantly from photobiont cells loosely attached to a fun­ gus to a more complex organization that in no way resembles the bionts that form it (1). Lichens are a very successful symbiosis; they are found in almost all terrestrial habitats, including tropical, desert and polar, and in fresh and salt water habitats. Lichens are dominant life forms in 8% of the earth’s terrestrial surface (2). The mycobiont, a heterotrophic organism, benefits from the carbohydrates produced by the photobiont. In the case of nitrogen-fixing cyanoLichens, the my­ cobiont also gains a nitrogen source. The fungus probably functions as a reservoir 117 118 Branquinho of inorganic nutrients for the photobiont and also creates a humid environment, enhancing water uptake, offers a physical support, and substantially reduces the light intensity for the photobiont. On the basis of their overall habitat, Lichens are traditionally divided into three main morphological groups: crustose, foliose, and fruticose. Crustose li­ chens are tightly attached to the substrate with their lower surface and may not be removed from it without destruction. Foliose Lichens are leaf-like, flat, and only partially attached to the substrate. Fruticose Lichens always stand out from the surface of the substrate (Fig. 1).

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  New and Future Developments in Microbial Biotechnology and Bioengineering

  Recent Advances in Application of Fungi and Fungal Metabolites: Current Aspects

  • Joginder Singh Panwar, Praveen Gehlot, Joginder Singh(Authors)
  • 2020(Publication Date)
  • Elsevier

    (Publisher)

  Chapter 7: Lichens: Fungal symbionts and their secondary metabolites

  Devashreea ; Anand Pandeyb ; Anupam Dikshita , *     

  a Biological Product Lab., Department of Botany, University of Allahabad, Prayagraj, India

  b Avvaiyar Government College for Women, Karaikal, Puducherry, India* Corresponding author. E-mail: [email protected]

  Abstract

  This chapter deals with the bioprospection of various lichen species. Lichens are mostly stable and self-supporting organisms. They form a combination of a symbiotic association between the dominant fungal partner (mycobiont) and the photoautotrophic algal partners (photobiont). In recent surveys and literature, it has been reported that about 1050 “lichen substances” have been characterized so far. The lichen-forming fungi are the main potential sources of polyketides and novel metabolites. Owing to their wide range of utility (food and fodder, perfumes, brewing and distilling, dyeing, etc.), Lichens have been described as the “treasure chest of natural products” and are regarded as among the most important bioresources. This is particularly true of the metabolites that have been produced from some specific Lichens that are generally known to exert many types of multiple pharmacological activities and also possess various properties such as antibiotic, antimycobacterial, antiviral, antiinflammatory, analgesic, antipyretic, antiproliferative, and cytotoxic. As slow-growing organisms, Lichens initially face many kinds of difficulties in sourcing the substantial quantities of lichen substances for various applications in their respective fields. The more improved and advanced culture procedures and methods as well as adjustable and suitable growing conditions in electronically controlled culture chambers have contributed to enormous progress in the field of Lichens as well as in the branch of biotechnology. The present study reports on morphological features, their secondary compounds, extraction, and their bioprospective values, especially focusing on their antimicrobial potential.

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  Fungal Biology

  • J. W. Deacon(Author)
  • 2009(Publication Date)
  • Wiley-Blackwell

    (Publisher)

  But, unfortunately, lichenology has a lexicon of almost impenetrable obscurity, which we will try to avoid as far as possible! The lichen partners There are estimated to be between 13,500 and 17,000 species of lichen, but we must begin with a note on taxonomy. Because Lichens are “dual organisms” com- posed of at least two separate species, there has always been a difficulty in naming them. This issue was only recently resolved by formally assigning Lichens to the fungal kingdom. So, for example, the common orange-yellow coloured lichen Xanthoria parietina (Fig. 13.11), which grows on rocks in coastal areas, is classified as a fungus (Xanthoria) that contains a photosynthetic partner – in this case, the green alga Trebouxia. In many Lichens the fungus, termed the mycobiont (the fungal symbiont), is a member of the Ascomycota (cup fungi), but in a few cases it can be a member of the Basidiomycota. The photosynthetic partner (the photobiont) can be either a green alga or a cyano- bacterium. However, a few Lichens contain both a green alga and a cyanobacterium, representing a symbiosis of three kingdoms of organisms. Almost all of the lichen fungi seem to be ecologically specialized, because they are found only in lichen partnerships and very rarely in a free-living state. FUNGAL SYMBIOSIS 267 Fig. 13.10 Section through part of the protocorm (basal stem region) of an orchid, Neottia, showing coils of hyphae (peletons) within the orchid cells. The cells were alive, as evidenced by the presence of nuclei (darker structures) in two of the orchid cells. Some have been grown in laboratory culture, but they grow very slowly and they lack the enzymes necessary for degrading organic polymers, so they are, effectively, constrained to live in a symbiosis. Only about 100 green algae have been found associated with Lichens. The most common are single-celled algae of the genus Trebouxia, found in most Lichens of temperate and cool regions.

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  Symbiosis (Biological Interactions Between Species)

  • (Author)
  • 2014(Publication Date)
  • White Word Publications

    (Publisher)

  Lichens have also been used in making dyes and perfumes, as well as in traditional medicines. Overview The body (thallus) of most Lichens is quite different from those of either the fungus or alga growing separately, and may strikingly resemble simple plants in form and growth. The fungus surrounds the algal cells, often enclosing them within complex fungal tissues unique to lichen associations. In many species the fungus penetrates the algal cell wall, forming penetration pegs or haustoria similar to those produced by pathogenic fungi. Lichens are poikilohydric, capable of surviving extremely low levels of water content. However, the re-configuration of membranes following a period of dehydration requires several minutes at least. During this period a “soup” of metabolites from both the mycobiont and phycobiont leaks into the extracellar spaces. This is readily available to both bionts to take up essential metabolic products ensuring a near perfect level of mutualism. Other epiphytic organisms may also benefit from this nutrient rich leachate. This phenomenon also points to a possible explanation of lichen evolution from its original phycobiont and mycobiont components with its subsequent migration from an aquatic environment to dry land. The algal or cyanobacterial cells are photosynthetic, and as in plants they reduce atmospheric carbon dioxide into organic carbon sugars to feed both symbionts. Both partners gain water and mineral nutrients mainly from the atmosphere, through rain and dust. The fungal partner protects the alga by retaining water, serving as a larger capture area for mineral nutrients and, in some cases, provides minerals obtained from the substrate. If a cyanobacterium is present, as a primary partner or another symbiont in addition to green alga as in certain tripartite Lichens, they can fix atmospheric nitrogen, complementing the activities of the green alga.

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  Lichens

  Toward a Minimal Resistance

  • Vincent Zonca, Jody Gladding(Authors)
  • 2022(Publication Date)
  • Polity

    (Publisher)

  “Lichenization” is the invention of a porous lifestyle, open to cooperation. Lichen is considered to be the result of a nutritional “strategy” of the fungus. In fact, the fungus is a heterotrophic organism: incapable (like human beings) of making the organic material it needs to nourish itself. Thus it needs other living beings: it can make use of the decomposition of soil (“saprophytism”), parasitize other species, or combine with them, as in the case of mychorrhizea and Lichens (as for algae, they are autotrophic: they produce their own organic material from inorganic material and minerals through photosynthesis). In this sense, lichen is a fungus that, in order not to depend on decomposition, cultivates algae, as though in a greenhouse, allowing it to live at greater heights. And it is because of this heterotrophy, which distinguishes it from plants, that the immobile fungus is essentially symbiotic: obliged to cohabit. The photosynthetic activity of chlorophyllic plants is coveted by other heterotrophic organisms. Other “photo-symbiotic” groupings were later discovered, notably in aquatic environments: the Roscoff worm (Symsagittifera roscoffensis) and the coral polyp both cohabit with single-celled algae for their respiration and nutrition (in the first case, the Tetraselmis convolutae alga, ingested without being digested by the Roscoff worm and surviving under its epidermis; in the second case, the zooxanthella, of the Symbiodinium genus). In these cases, they unite animal and vegetable kingdoms. * In lichen there is link. For many years now, certain biologists, philosophers, and artists have seized on this organism to question The Politics of Lichen 175 the notion of biological individuality (indiv: in Latin, that which cannot be divided, like Leibniz’s monad, Lucretius’ atom).

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  Synergistic Approaches for Bioremediation of Environmental Pollutants: Recent Advances and Challenges

  • Riti Thapar Kapoor, Maulin P. Shah, Riti Thapar Kapoor, Maulin P. Shah(Authors)
  • 2022(Publication Date)
  • Academic Press

    (Publisher)

  Bayazıt et al., 2018 ).

  Recently, Lücking et al. (2021) redefined Lichens as “a stable, self-supporting association of a fungus or fungal-like organism, the primary mycobiont, and a morphologically undifferentiated, unicellular to filamentous alga and/or a cyanobacterium, the primary (and secondary) photobiont, along with obligately associated elements of the fungal and bacterial microbiome contained therein. The phenotype of the mycobiont in the lichenized state (the exhabitant) typically functions as a greenhouse around the photobiont (the inhabitant), the mechanical, physiological, and evolutionary properties of the symbiosis thereby exhibiting analogies with agriculture” (Lücking et al., 2021 ).

  The mycobiont partner associated with it determines the lichen morphology, and hence, their classification is combined with the fungi system. As a result, Lichens can be considered fungi that develop self-sustaining living forms with algae. Mycobiont partners are mostly Ascomycetes, with a few belonging to Basidiomycetes. The majority of photobiont partners among the 20,000 recorded species of Lichens are members of Chlorophyceae (green algae), with only 10% belonging to Cyanophyceae (blue-green algae) (Hawksworth et al., 1995 ; Nash and Nash, 1996 ).

  Lichens grow at a considerably slower rate than higher plants and have a remarkable ability to withstand unfavorable environmental conditions. They have been used in traditional culture for various reasons, including the preparation of spices, nutraceuticals, pharmaceuticals, dyes, and perfumes. Due to their unique physiology and ability to survive in harsh environments, Lichens generate many novel secondary metabolites, which outweighs the interest in these chemicals as possible pharmacophore sources (Tripathi et al., 2021 ). Another interesting feature of Lichens is that they are the early and successful colonizers in the extreme terrestrial ecosystems, including metalliferous environments. They are potent accumulators/adsorbers of heavy metals in the atmosphere and can be used as low-cost bio-monitoring agents to determine the presence of several heavy metals and other harmful pollutants in the atmosphere. Globally, several research groups have studied the ability of Lichens to acquire metals such as Cd, Cr, and Pb from the metalliferous substrates. For instance, transplanted Lichens such as Evernia prunastri showed hyperaccumulation of Pb, while Hypogymnia physodes showed hyperaccumulation of Cd and Pd at various altitudes (Conti and Cecchetti, 2001 ). The lichen Usnea has shown hyperaccumulation of heavy metals in Antarctica (Poblet et al., 1997 ), while Lichens such as Cladonia portentosa have been used to study acid precipitation index (Conti and Cecchetti, 2001 ). These species use several cellular mechanisms to absorb and accumulate metals at a higher level than usual for an extended period. Lichens also play other vital roles in the ecology, such as appearing as primary colonizers in the forest area after a fire and carrying out nitrogen fixation and recycling (Grimm et al., 2021 ). Peltigera and Stereocaulon

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  Eukaryotic Microbes

  • Moselio Schaechter(Author)
  • 2011(Publication Date)
  • Academic Press

    (Publisher)

  Yet Lichens do not appear in most macroecological analyses of the biosphere. A great deal more ecological work is needed in order to model the role of Lichens in natural ecosystems. Lichens are widely distributed, but many species are highly sensitive to their environment and reflect a narrow and specialized geographic distribu-tion. While all lichen species tolerate a great range of envi-ronmental conditions, especially as regards water relations, they are threatened by numerous anthropogenic changes in their environment. There is much to learn about the physiological mechanisms by which Lichens function as photosynthetic units in challenging environments. Lichens have always been difficult to identify on the ba-sis of their variability and human limitations in describing lichen form. Generally, the group has suffered because too few scientists undertake the study of Lichens. Much more floristic work is required in order to better document lichen populations worldwide. As lichen habitats are destroyed by human interference, the species will inevitably be lost. Further resources are required, not only to identify and record lichen species but also to explore the numerous physiological phenomena that characterize the symbiosis. Lichens are subject to evolution like every organism on the planet. Their evolutionary history suggests an ancient lineage that has weathered innumerable changes in the environment. That evolutionary history is complicated by the presence of two or more symbionts in every lichen species. Further research will elucidate not only the evolu-tionary relationships of Lichens but also the nature of their symbiosis. FURTHER READING Ahmadjian, V. (1993). The lichen symbiosis. Wiley: New York. Ahmadjian, V., & Paracer, S. (1986). Symbiosis: An introduction to biolog-ical associations. University Press of New England: Worcester, MA. Cornelissen, J. H., Lang, S. I., Soudzilovskaia, N. A., & During, H.

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  Stress in Yeasts and Filamentous Fungi

  • Simon Avery, Malcolm Stratford, Pieter van West(Authors)
  • 2007(Publication Date)
  • Academic Press

    (Publisher)

  Under-standing metal uptake and retention by Lichens is important for environ-mental monitoring, understanding global biogeochemical cycles, learning how organisms tolerate potentially toxic elements and for conservation. British Mycological Society Symposia Series r 2008 The British Mycological Society Published by Elsevier Ltd. All rights reserved. 175 1. INTRODUCTION Lichenised fungi play a role in the evolution of terrestrial life, ecosystem function and the maintenance of biodiversity (Hawksworth, 1988, 1991; Nash, 1996a; Schwartzman, 2002; Gorbushina, 2006). Composite organisms, Lichens, include at least one fungus (mycobiont) and an alga or cyanobacterium (photobiont) living in symbiosis. Lichenised fungi are ecologically obligate biotrophs acquiring car-bon from their photobionts (Honegger, 1997). The lichen symbiosis may involve multiple and different bionts at various stages of its life history (Hawksworth, 1988; Jahns, 1988). Lichens colonise bark, rocks and soil and occur in all terrestrial ecosystems, covering about 6% of the earth’s land surface. They are dominant in arctic and antarctic tundra regions where they form an important part of the food chain. Arctic and sub-arctic lichen heaths are readily visible from space using remote sensing techniques (Tømmervik et al ., 1995, 1998, 2003). Lichens play a major role in plant ecology and the cycling of elements, such as C, N and P and radionuclides (Knops et al ., 1991; Schwartzman, 1993; Nash, 1996b). They contribute to soil formation and stabilisation (Jones, 1988). Metalliferous habitats that are so toxic that they support few, if any higher plants often have abundant crustose ‘metallophyte’ Lichens, including rare species. Some grow directly on minerals (Gilbert, 1980, 2000; Purvis and Halls, 1996; Haas and Purvis, 2006). Lichens colonise contaminated sites near metal smelters (LeBlanc et al ., 1972; Nash, 1972, 1989, 1996b; Purvis et al ., 2000; Cuny et al ., 2004a).

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  The Lives of Lichens

  A Natural History

  • Robert Lücking, Toby Spribille(Authors)
  • 2024(Publication Date)
  • Princeton University Press

    (Publisher)

  Jelly Lichens owe this phenomenon to their photobiont, the cyanobacterium Nostoc. In jelly Lichens, the Nostoc colonies retain their copious gelatinous matrix, helping the lichen to retain water longer than in other Lichens. Enchylium tenax is a component of biological soil crusts in arid regions. Given just enough moisture, these biocrusts form a thin “skin” over soil, helping to prevent erosion. The importance of biological soil crusts has consequently come to be recognized in land management everywhere, from Africa to the Gobi Desert to the American Southwest. That the Nostoc in these Lichens also fixes nitrogen constitutes added value in ecosystems with limited nutrients.  Dry, Coal Miner’s Snot Lichen. 75 A D A Y I N T H E L I F E O F A L I C H E N  Wet, Coal Miner’s Snot Lichen. 76 This process, referred to in biology as vitrification— being turned into glass—is found in a smattering of different organisms, including resurrection ferns, mosses, and the larvae of some insects, which pass time waiting for the next dose of water. It is something we humans struggle to relate to, an alien superpower that enables organisms we would assume to be dead to spring back to life. How exactly lichen symbionts pull off this feat is not understood, but there are hints that these abilities may be the very thing that the symbiosis enables. SUGAR ALCOHOLS: JANUS CARBOHYDRATES During its photosynthetic frenzy, the photobiont fixes carbon and builds up an internal pool of carbohydrates. As briefly discussed on page 26, these are usually sugar alcohols, also known as polyols, and after they are transferred to the fungus, they tend to remain in this specific molecular form. This is not a given—many other forms of life would convert their carbs into other flavors, so the apparent insistence of Lichens on keeping their carbs in the form of sugar alcohols has raised some scientists’ eyebrows.

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  Defensive Mutualism in Microbial Symbiosis

  • James F. White Jr., Monica S. Torres(Authors)
  • 2009(Publication Date)
  • CRC Press

    (Publisher)

  Journal of Chemical Ecology 13:363–369. Richardson, D. H. S. 1975. The Vanishing Lichens . Vancouver: David and Charles. Richardson, D. H. S. 1999. War in the world of Lichens: parasitism and symbiosis as exemplified by Lichens and lichenicolous fungi. Mycological Research 103:641–650. Rikkinen, J. 1995. What’s behind the pretty colours? A study on the photobiology of Lichens. Bryobrothera 4:1–239. Rundel, P. W. 1969. Clinal variation in the production of usnic acid in Cladonia subtenuis along light gradients. Bryologist 72:40–44. Rundel, P. W. 1978. The ecological role of secondary lichen substances. Biochemical and Systematic Ecology 6:157–170. Sancho, L. G., de la Torre, R., Horneck, G., Ascaso, C., de los Ríos, A., Pintado, A., Wierzchos J., and M. Schuster. 2007. Lichens survive in space: Results from the 2005. Lichens experiment. Astrobiology 7:443–454. Sanders, W. B. 2001. Lichens: The interface between mycology and plant morphology. BioScience 51:1025–1035. Schatz, A. 1962. Pedogenic (soil-forming) activity of lichen acids. Naturwissenschaften 49:518. Seaward, M. R. D. 1965. Lincolnshire psocids. Transactions of the Lincolnshire Naturalists’ Union 16:99–100. Seyd, E. L. and M. R. D. Seaward. 1984. The association of oribatid mites with Lichens. Zoological Journal of the Linnean Society 80:369–420. Sharnoff, S. http://www.Lichens.com/invertebrates.html Sigal, L. L. 1984. Of Lichens and lepidopterans. Bryologist 87:66–68. Slansky, Jr. F. 1979. Effects of the lichen chemicals atranorin and vulpinic acid upon feeding and growth of lar-vae of the yellow-striped armyworm, Spodoptera ornithogalli. Environmental Entomology 8:865–868. Solhaug, K. A. and Y. Gauslaa. 1996. Parietin, a photoprotective secondary product of the lichen Xanthoria parietina. Oecologia 108:412–418. Solhaug, K. A. and Y. Gauslaa. 2001. Acetone rinsing—a method for testing ecological and physiological roles of secondary compounds in living Lichens.

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