Lichens sources

Over the past decade 52 new depsides have been reported. Table 4 at the end of this section (p. 160) lists the structure and the lichen source and summarizes the method of separation and structural elucidation of these compounds. 

The next several entries feature examples from the lichen literature. Study of chemical constituents of lichens has proved an invaluable source of information on relationships within this widespread group of organisms. The first example, Pseudevernia furfuracea (= Parmelia furfuracea) involves a disjunction across the Atlantic Ocean, bnt other examples in this set enjoy mnch wider—and often unusual—disjunctions. This example is inclnded here in order to keep the lichen material in one place. 

The accident at the Chernobyl, Ukraine, nuclear reactor on April 26, 1986, contaminated much of the northern hemisphere, especially Europe, by releasing large amounts of radiocesium-137 and other radionuclides into the environment. In the immediate vicinity of Chernobyl at least 30 people died, more than 115,000 others were evacuated, and the consumption of locally produced milk and other foods was banned because of radiocontamination. The most sensitive local ecosystems were the soil fauna and pine forest communities. Elsewhere, fallout from Chernobyl measurably contaminated freshwater, marine, and terrestrial ecosystems, including flesh and milk of domestic livestock. Reindeer (Rangifer tarandus) calves in Norway showed an increasing frequency of chromosomal aberrations that seemed to correlate with cesium-137 tissue concentrations tissue concentrations, in turn, were related to cesium-137 in lichens, an efficient absorber of airborne particles containing radiocesium and the main food source of reindeer during winter. A pattern similar to that of reindeer was documented in moose (Alces) in Scandinavia. 

Lichens, the natural source of paraconic acids [1], are a successful alliance between fungi and algae. Each is doing what they do best, and thriving as a... 

The algae above-mentioned are manifestly the source of the dyestuff and as suggested by Berthelot were probably lichens such as were formerly much used and which yield the dyestuff called archil or orseille. 

Most of the previously identified 25 chlorinated anthraquinones are found in lichen and fungi (1). The newly discovered examples have a wider range of sources. Studies of the lichen Nephroma laevigatum from the British Columbia coast have identified the new anthraquinone, 7-chloro-l-O-methyl-co-hydroxy-emodin (2157), and the two novel hypericins, 7,7 -dichlorohypericin (2158) and 2,2, 7,7 -tetrachlorohypericin (2159) (1931), as well as 5-chloroemodin (2160), 5-c h I oro -1 - (9 - m e t h v I - o >- h yd ro x ye m od i n (2161), and 5-chloro-co-hydroxyemodin (2162) (1932). In addition to containing several known chlorinated anthraquinones, the Scandinavian fungus Dermocybe sanguinea has afforded the new 5,7-dichloroendocrocin (2163) (1933). The novel tetracyclic anthraquinones... 

What exactly was manna Its sweetness, and the fact that it was available in an arid land, suggests it was rich in trehalose. This being so, then there are several possible sources. It may have been the cocoon of a parasitic beetle, called trehala mana, which contains around 25% trehalose. A possible contender is the solidified juice of the flowering ash, also known as the manna ash (Fraxinus omus) which oozes from its bark and solidifies. This too is collected and sold commercially. Another suggestion is that manna is the lichen Lecano-ra which curls up into balls when there is a drought. These can be blown by the wind and are sometimes collected and used to make... 

To the best of our knowledge, the few chemical studies reporting isolation and characterization of terphenyls from natural sources not belonging to the Kingdom of Fungi are confined to lichens, and are shortly reported here. 

Mushrooms and various fungi and lichens are rich in enol metabolites and many exhibit significant bioactivities , such as usnic acid (14) which serves as a regulator for plant growth and shows antitumor and antibiotic activities " . The widely distributed quinone polyporic acid (15a, PPA) from the Purple-Dye Polypore mushroom (Hapalopilus nidu-lans) and other sources is a weak inhibitor (IC50 = 0.1 to >1.5 mM " ) of dihydroorotate... 

Wadleigh M. A. and Blake D. M. (1999) Tracing sources of atmospheric sulphur using epiphytic lichens. Environ. Pollut. 106, 265 - 271. 

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