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Current results on biological activities of lichen secondary metabolites: a review.

Lichens are symbiotic organisms of fungi and algae or cyanobacteria. Lichen-forming fungi synthesize a great variety of secondary metabolites, many of which are unique. Developments in analytical techniques and experimental methods have resulted in the identification of about 1050 lichen substances (including those found in cultures). In addition to their role in lichen chemotaxonomy and systematics, lichen secondary compounds have several possible biological roles, including photoprotection against intense radiation, as well as allelochemical, antiviral, antitumor, antibacterial, antiherbivore, and antioxidant action. These compounds are also important factors in metal homeostasis and pollution tolerance of lichen thalli. Although our knowledge of the contribution of these extracellular products to the success of the lichen symbiosis has increased significantly in the last decades, their biotic and abiotic roles have not been entirely explored.

Species richness of lichen functional groups in relation to land use intensity

Changing land use has a major impact on lichen diversity. This study attempts to identify patterns or trends of lichen functional groups along a land use gradient, ranging from natural forests to open agricultural landscape. In eight countries, covering six main European biogeographic regions, lichen vegetation was assessed according to a standardized scheme. Data on reproductive, vegetative and ecological traits was compiled and relative species richness for all classes of all traits calculated. Relationships between the land use gradient and relative species richness of trait classes were analysed. Open and intensively managed landscapes harbour more fertile species while sterile species are relatively more important in forests. This finding is also supported by analyses of different classes of dispersal propagules. The importance of species with the principal photobiont Trebouxia s.l. increases linearly with intensification of land use. A converse pattern is revealed by species with Trentepohlia. Concerning substratum specialization only generalists show an effect along the land use intensity gradient. Their relative species richness decreases from landscapes dominated by forests to open agricultural landscape. A considerable decline in the rare lichen species richness as a result of land intensification is predicted.

Laser spectrometry and kinetics of selected elementary reactions of the acetonyl radical

The laser induced fluorescence excitation spectrum (LIF) and the ultraviolet absorption spectrum (TA) of the acetonyl radical (CH3C(O)CH2) were remeasured by using the time-resolved fast discharge flow (DF) and laser flash photolysis (LP) experimental techniques (T = 298 K). The absorption cross section of σ(acetonyl, 207 nm) = (3.16 ± 0.61) × 10−18 cm2 molecule−1 was determined calibrated against the acetyl-peroxyl radical (CH3C(O)O2) in LP/TA measurements. The kinetics of the reactions of CH3C(O)CH2 with the open shell reaction partners O2 (1), NO (2), NO2 (3) and H (4) were studied by using the DF method with LIF detection of the acetonyl radical at 298 ± 1 K and 2.85 ± 0.05 mbar He pressure. The rate constants for the overall reactions were determined in units of cm3 molecule−1 s−1 to be k1 = (3.49 ± 0.51) × 10−13, k2 = (1.04 ± 0.19) × 10−11, k3 = (3.25 ± 0.65) × 10−11 and k4 ≥ 3 × 10−10 with 2σ accuracy given. The acetonyl radical was found to react similarly to alkyl radicals by comparison with literature results. A reduced reactivity was observed toward O2 and NO that might be attributed to the resonance stabilisation of the acetonyl radical. No such effect was observed for the NO2 and H atom reactions.

Neue foliicole Arten der Flechtengattung Dimerella Trevisan ( Gyalectaceae ) aus Tansania

Five new foliicolous species ofDimerellaTrevisan (Gyalectaceae) are reported from a collection of lichens from Tanzania:D. flavicans sp. n.,D. pocsii sp. n.,D. subdilucida sp. n. ad int.,D. tanzanica, sp. n. andD. usambarensis sp. n. A determination key is provided to all the known African foliicolous species.

A contribution to the taxonomy of Lyromma (Lyrommataceae, lichenized Ascomycota) with a species key

The paper presents a new concept of conidial-ascosporic relationship in the foliicolous lichenized genus Lyromma and a revised key to species determination. Lyromma coronatum sp. nov. (Bolivia) is characterized by reduced perithecial appendages composed of clavate hyphae that form a crown around the ostiole. Lyromma multisetulatum sp. nov. (Bolivia, Brazil) is characterized by numerous large strongly recurved perithecial appendages composed of individual acicular hyphae. Undescribed ascosporic states for Lyromma dolicobelum and L. palmae and conidial states for L. ornatum and L. pilosum are described based on observations of perithecia and pycnidia for the first time in natural conditions. Confirmation of a conidial-ascosporic connection for L. nectandrae suggests L. confusum as a synonym. Lyromma dolicobelum, L. nectandrae, and L. ornatum are reported as new to Bolivia, and L. pilosum as new to Bolivia and Brazil.

Depsides and Depsidones in Populations of the Lichen Hypogymnia physodes and Its Genetic Diversity

The aim of this study was to determine the extent and geographical pattern of intraspecific chemical and genetic variability of the lichen Hypogymnia physodes by comparing populations from different habitats. We analyzed the secondary lichen substances and their relative concentrations using HPTLC and HPLC in samples collected from sites with different environmental conditions. We identified seven lichen substances: the cortical atranorin and chloroatranorin, and the medullary physodalic, physodic, protocetraric, 3-hydroxyphysodic, and 2′-0-methylphysodic acids. The samples were uniform qualitatively, which means that H. physodes has only one chemotype. We detected quantitative chemical differences between the samples without any geographical pattern. We investigated 21 samples in order to study the connection between genotypic diversity of populations and geographical distribution. We determined the sequences of five loci (ITS, nucSSU, nucLSU, mitSSU, EF1&agr;). We found no significant genetic differentiation among populations collected from different areas.

Pseudocyphellaria crocata (Ascomycota: Lobariaceae) in the Americas is revealed to be thirteen species, and none of them is P. crocata

Abstract We provide a phylogenetic revision of the Pseudocyphellaria crocata complex in the Americas. Specimens traditionally identified as P. crocata, based on their cyanobacterial photobiont, yellow pseudocyphellae, at least partially white medulla, and yellow soralia or soralia-like structures, are shown to represent 13 distinct species, forming a monophyletic group divided into four large clades, three comprising one species each and one containing eight species, plus two taxa for which no molecular data are available. Seven species correspond to what was previously recognized as P. crocata and one to P. dozyana, whereas a further one is identified as the sorediate counterpart of the usually apotheciate taxon P. lechleri and another as a pseudosorediate morph of the usually phyllidiate species P. neglecta. Surprisingly, none of the species represents P. crocata s.str., which must therefore be excluded from the American lichen biota. The 13 recognized species include three species new to science and three new combinations: P. citrina (Gyeln.) Lücking, Moncada & S.Stenroos, comb. nov. [bas.: Cyanisticta citrina Gyeln., nom. nov. pro Sticta citrina Pers. nom. illeg.], P. desfontainii (Delise) Vain., P. deyi Lücking, sp. nov., P. dozyana (Mont. & Bosch) D.J.Galloway, P. epiflavoides (Gyeln.) Lücking, Farkas & Lőkös, comb. nov. [bas.: Cyanisticta epiflavoides Gyeln.], P. hawaiiensis H.Magn., P. hillii (C.W.Dodge) D.J.Galloway, P. holarctica McCune, Lücking & Moncada, sp. nov., P. lechleri (Müll. Arg.) Du Rietz, P. neglecta (Müll. Arg.) H.Magn., P. punctata Lendemer, Lücking & Moncada sp. nov., P. sandwicensis (Zahlbr.) Moncada & Lücking, comb. nov. [bas.: Sticta crocata f. sandwicensis Zahlbr.], and P. xanthosticta (Pers.) Moncada & Lücking. Based on sequenced specimens, a neotype is selected for P. citrina and epitypes for P. hawaiiensis, P. lechleri, P. sandwicensis and P. xanthosticta. A key to all sorediate or pseudosorediate species of this complex in the Americas is presented, and all species are described, discussed and illustrated.

New Chemotypes of the Lichens Xanthoparmelia pulvinaris and X. subdiffluens (Parmeliaceae, Ascomycota)

Abstract: Farkas, E., Kursinszki, L., Szőke, É. & Molnár, K. 2015. New chemotypes of the lichens Xanthoparmelia pulvinaris and X. subdiffluens (Parmeliaceae, Ascomycota). — Herzogia 28: 679–689. New chemotypes of Xanthoparmelia pulvinaris and X. subdiffluens containing norstictic acid were identified among many of the Hungarian collections of these species using HPTLC and confirmed by LC-MS. The two species are characterised, the possible functional role of norstictic acid is briefly discussed and the importance of protecting populations with norstictic acid in nature is emphasized.

Rare or Overlooked? — Two Species of Lyromma (Lyrommataceae, Lichenized Ascomycota) are New for Africa

Abstract: Farkas, E. & Flakus, A. 2015. Rare or overlooked? — Two species of Lyromma (Lyrommataceae, lichenized Ascomycota) are new for Africa. — Herzogia 28: 204–211. Two species of the foliicolous lichenized genus Lyromma so far known only from the Neotropics are reported for the first time from Africa. Lyromma multisetulatum, described from Bolivia and Brazil, was found recently in Kenya and Tanzania, and L. pilosum in Tanzania. Tanzanian specimens were discovered in lowland rainforest collections from 200 to 500 m altitude. The Kenyan collection originates from moist montane forests at c. 2000 m elevation. Both species are characterized by both perithecia and pycnidia observed on the same thallus. The distribution and frequency of these taxa are briefly discussed, and compared to other taxa with similar distribution patterns.

Lectotypification of names of lichen taxa described by Ödön Szatala

The Hungarian lichenologist Odon Szatala described 169 species and infraspecific taxa, with a majority of these being based on his own collections. He also described taxa from material sent to him for identification. In this study, original material for 27 names (Aspicilia latiloba, A. microspora var. astroidea, A. microspora var. insensibilis, A. subpercaena, Bacidia rhodi, Buellia samothrakiana, Catillaria lenticularis var. transsilvatica, C. servitii, C. zsakii, Dermatocarpon fuscatum, Diplotomma alboatrum var. virescens, Lecania nylanderiana var. ochracea, Lecanora atra var. aegaeica, L. cengiae-samboae, L. rhodi, Lecidea aegaeica, L. aegaeica f. acrustacea, L. aegaeica f. albida, L. aegaeica var. verruculosa, L. euphorea f. decussata, L. iranica, L. stigmatea f. armeniaca, Pertusaria baskalensis, Physcia grisea var. elbursiana, Placodiella olivacea var. stampaliana, Porina rechingeri and Verrucaria filarszkyana) of taxa described by Szatala and based on material collected by others from Greece, Hungary, Iran, Iraq, Jordan, Palestine, Romania, Turkey and Ukraine was examined, and lectotypes were chosen. In addition, Catillaria servitii has been found to be the earliest name for C. praedicta.