Rhizoplaca Chrysoleuca Research Articles

Green synthetic biomaterials: Synthesis, characterization and antimicrobial properties of lichen-derived nanomaterials

The green synthesis of nanoparticles using lichen extracts offers a safer and more environmentally friendly alternative to traditional methods. Known for their medicinal properties, lichens can effectively reduce and stabilise metallic salts, providing an eco-friendly approach to producing nanomaterials with potential antimicrobial applications. In this study, the lichen Rhizoplaca chrysoleuca was utilised in the green synthesis of nanoparticles, successfully creating lichen-derived silver-zinc oxide (Ag–ZnO), silver-strontium oxide (Ag–SrO), and silver-nickel oxide (Ag–NiO) nanoparticles. Ultraviolet–visible absorption spectroscopy revealed that the characteristic light absorption of the NCs occurred within the range of 300–400 nm for each synthesis, and dynamic light scattering measurements indicated that the hydrodynamic diameters of the nanoparticles were below 100 nm. Energy-dispersive X-ray spectroscopy confirmed the presence of the constituent elements. Imaging with field-emission scanning electron microscopy and scanning transmission electron microscopy showed that the nanoparticles had spherical shapes with dimensions measuring below 50 nm. X-ray diffraction analysis of the synthesised nanocomposite materials revealed the presence of Ag–ZnO (22 nm), Ag–SrO (48 nm), and Ag–NiO (21 nm) nanoparticles. Fourier-transform infrared spectroscopy identified functional groups in the nanoparticles, confirming their compositions, while thermogravimetric analysis determined the thermal decomposition temperatures of the NCs. The antibacterial efficacy of these materials was assessed, with Ag–ZnO (inhibition zone 11.0 mm) and Ag–NiO (inhibition zone 10.0 mm) showing significant effectiveness against both Gram-negative and Gram-positive bacteria. In contrast, Ag–SrO (inhibition zone 6.5 mm) exhibited comparatively lower antibacterial activity. Additionally, the study highlighted the antifungal properties of Ag–NiO (inhibition zone 19.0 mm) and Ag–ZnO (inhibition zone 8.5 mm) nanomaterials. This research advances the understanding of lichen-based nanotechnology and its potential for developing sustainable antimicrobial solutions.

Kirliliğin biyomonitörleri olarak çeşitli likenlerdeki bazı eser elementlerin belirlenmesi ve kirlilik durumunun değerlendirilmesi

Some trace elements in various lichens as biomonitors of pollution were investigated. Also, the pollution status was assessed by enrichment factor, contamination factor, and pollution loud index. Investigated elements were Ta, Bi, Hf, Nb, Ga, Sc, Li, Y, Ce, and Sr. The lichen species were Rhizoplaca chrysoleuca, Umbilicaria vellea, Aspicilia calcarea, Pseudevernia furfuracea, and Cetraria islandica. According to the results, lichen species accumulate Sr element well. The highest trace element accumulated by Pseudevernia furfuracea (21.7±1.0 mg/kg; 75%), Rhizoplaca chrysoleuca (31.9±1.6 mg/kg; 61%), Umbilicaria vellea (16.3±0.8 mg/kg; 59%), Aspicilia calcarea (77.9±3.8 mg/kg; 88%), and Cetraria islandica (22.7±1.1 mg/kg; 75%) was determined as Sr. EF values for Rhizoplaca chrysoleuca (Bi: 11.87 and Y:10.25) and Aspicilia calcarea (Sr:11.18 and Bi:11.87) were greater than 10. EF values for Cetraria islandica, Pseudevernia furfuracea and Umbilicaria vellea were

A first synopsis of lichenicolous fungi of Mongolia, with the description of five new species

AbstractA first synopsis of lichenicolous fungi of Mongolia based on new collections and literature data is provided, including 114 species. Five new species are described: Capronia cogtii (on Vahliella leucophaea), Echinothecium hypogymniae (on Hypogymnia bitteri), Feltgeniomyces mongolicus (on H. bitteri), Phacopsis vulpicidae (on Vulpicida juniperina) and Roselliniella javkhlanae (on Rinodina turfacea var. ecrustacea). Two new combinations are proposed: Endococcus hafellneri (≡ Stigmidium hafellneri) and Sphaerellothecium taimyricum (≡ Sphaerellothecium thamnoliae var. taimyricum). Unidentified specimens of Acremonium (on Mycoblastus sanguinarioides), Cercidospora (on Rhizoplaca chrysoleuca s.lat.), Didymocyrtis (on Rhizoplaca chrysoleuca s.lat.), Lichenochora (on Physcia alnophila), Lichenostigma (on species of Xanthoparmelia), Phoma (on Vulpicida juniperina) and a leotialean fungus (on Cetraria laevigata) are characterized and discussed. Taxonomic notes are provided for Cercidospora macrospora s.lat., Didymocyrtis cf. melanelixiae, Minutoexcipula cf. beaglei, Nesolechia cetrariicola, Sphaerellothecium cf. parmeliae and Stigmidium cf. psorae. Sphaeropezia intermedia is newly reported for Eurasia. Didymocyrtis grumantiana is newly reported for Asia. Additionally, 71 species of lichenicolous fungi and five species of lichenicolous lichens are documented in Mongolia for the first time. Allocetraria is reported as a new host genus for Abrothallus peyritschii, Vulpicida for Arthonia triebeliae, and Anamylopsora for Muellerella pygmaea.

Element bioaccumulation in lichens transplanted along two roads: The source and integration time of elements

The biomonitoring of atmospheric element deposition via lichen transplantation is a powerful tool for assessing air quality in polluted areas devoid of native or expected lichens. In this paper, we explore how the elemental compositions in lichens respond to road emissions and compared the lichen responses under high air pollution conditions. Two foliose lichens, Flavopunctelia soredica (FS) and Rhizoplaca chrysoleuca (RC), were transplanted along two roads in a highly polluted area of Hebei, China. FS and RC were exposed to the road emissions for 3, 6, 9 and 12 months, and 25 elements (Al, Ba, Ca, Cd, Co, Cs, Cu, Fe, K, La, Mg, Mn, Na, Ni, Pb, Rb, S, Sb, Sm, Sr, Tb, Th, Ti, V, and Zn) were measured using an inductively coupled plasma mass spectrometer (ICP-MS). The pre-exposure and post-exposure results were higher in RC for 6 metals (Ca, Cd, Pb, La, Sm, and Tb), were higher in FS for 13 elements (Al, Ba, Co, Cu, Fe, K, Mg, Mn, Ni, Rb, S, V, and Zn), but were not significantly different between FS and RC for 3 metals (Cs, Sr, and Th), indicating that the element concentrations are specific to the element and lichen species. The results also showed a certain degree of air pollution at the initial site and severe air pollution at the exposure sites. During the exposure period, FS and RC exhibited roughly similar spatio-temporal patterns in element concentrations, with significant increases observed in relation to the distance to the road and exposure time. This result suggests that FS and RC are applicable as bioaccumulators and present good comparability. The release of SO2 in the winter heating period elevated the lichen S concentrations, for which the lichens have an integration time of <3 months, whereas the road emissions accelerated the accumulation of metals, for which the lichens have an integration time of >3 months.

Antioxidant capacities, phenolic profile and cytotoxic effects of saxicolous lichens from trans-Himalayan cold desert of Ladakh.

Fourteen saxicolous lichens from trans-Himalayan Ladakh region were identified by morpho-anatomical and chemical characteristics. The n-hexane, methanol and water extracts of the lichens were evaluated for their antioxidant capacities. The lichen extracts showing high antioxidant capacities and rich phenolic content were further investigated to determine their cytotoxic activity on human HepG2 and RKO carcinoma cell lines. The ferric reducing antioxidant power (FRAP), 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), 1,1-diphenyl-2-picrylhydrazyl (DPPH) and nitric oxide (NO) radical scavenging capacities and β-carotene-linoleic acid bleaching property exhibited analogous results where the lichen extracts showed high antioxidant action. The lichen extracts were also found to possess good amount of total proanthocyanidin, flavonoid and polyphenol. The methanolic extract of Lobothallia alphoplaca exhibited highest FRAP value. Methanolic extract of Xanthoparmelia stenophylla showed the highest ABTS radical scavenging capacity. The n-hexane extract of Rhizoplaca chrysoleuca exhibited highest DPPH radical scavenging capacity. Highest antioxidant capacity in terms of β-carotene linoleic acid bleaching property was observed in the water extract of Xanthoria elegans. Similarly, Melanelia disjuncta water extract showed highest NO scavenging capacity. Among n-hexane, methanol and water extracts of all lichens, the methanolic extract of Xanthoparmelia mexicana showed highest total proanthocyanidin, flavonoid and polyphenol content. From cytotoxic assay, it was observed that the methanolic extracts of L. alphoplaca and M. disjuncta were exhibiting high cytotoxic effects against cancer cell growth. Similarly, the water extract of Dermatocarpon vellereum, Umbilicaria vellea, X. elegans and M. disjuncta and the methanolic extract of M. disjuncta and X. stenophylla were found to possess high antioxidant capacities and were non-toxic and may be used as natural antioxidants for stress related problems. Our studies go on to prove that the unique trans-Himalayan lichens are a hitherto untapped bioresource with immense potential for discovery of new chemical entities, and this biodiversity needs to be tapped sustainably.

Mutation preventive and antigenotoxic potential of methanol extracts of two natural lichen

We aimed to determine the mutagenic, antimutagenic and antigenotoxic effects ofRhizoplaca chrysoleuca and Rhizoplaca melanophthalma's methanol extracts on the known mutagens against two different organisms using Mitotic Index (MI) and Ames-Salmonella assay systems. For the MI assay the genotoxic dose of NaN3was defined on Zea mays seeds and different dose of the lichen extract used as anti-mutagen (5, 10, 20, 40 μg/plate). Observed data showed that methanol extracts prevent the cytotoxic effect of NaN3 partially. In addition, the antimutagenic activities of the methanol extracts were investigated against 9-AA in TA1537 and NaN3 in TA1535 strains of Salmonella typhimurium. Extracts show antimutagenic effect against 9-AA-induced mutation in TA1537 strain at all tested concentrations. The inhibition rates ranged from 70.73 to 85.71% (R. chrysoleuca, 0.5 μg/plate - 5 μg/plate). The results show that these natural compounds have an ability to reduce or prevent the effects of these mutagenic substances. Key words: Ames, Salmonella, antimutagenicity, genotoxicity, mitotic index,Rhizoplaca chrysoleuca, Rhizoplaca melanophthalma.

Ascomycota has a faster evolutionary rate and higher species diversity than Basidiomycota

Differences in rates of nucleotide or amino acid substitutions among major groups of organisms are repeatedly found and well documented. A growing body of evidence suggests a link between the rate of neutral molecular change within populations and the evolution of species diversity. More than 98% of terrestrial fungi belong to the phyla Ascomycota or Basidiomycota. The former is considerably richer in number of species than the latter. We obtained DNA sequences of 21 protein-coding genes from the lichenized fungus Rhizoplaca chrysoleuca and used them together with sequences from GenBank for subsequent analyses. Three datasets were used to test rate discrepancies between Ascomycota and Basidiomycota and that within Ascomycota: (i) 13 taxa including 105 protein-coding genes, (ii) nine taxa including 21 protein-coding genes, and (iii) nuclear LSU rDNA of 299 fungal species. Based on analyses of the 105 protein-coding genes and nuclear LSU rDNA datasets, we found that the evolutionary rate was higher in Ascomycota than in Basidiomycota. The differences in substitution rates between Ascomycota and Basidiomycota were significant. Within Ascomycota, the species-rich Sordariomycetes has the fastest evolutionary rate, while Leotiomycetes has the slowest. Our results indicate that the main contribution to the higher substitution rates in Ascomycota does not come from mutualism, ecological conditions, sterility, metabolic rate or shorter generation time, but is possibly caused by the founder effect. This is another example of the correlation between species number and evolutionary rates, which is consistent with the hypothesis that the founder effect is responsible for accelerated substitution rates in diverse clades.

Recent Literature on Lichens—211

Ahti, T., S. Parnmen & P. Mongkolsuk. 2008. Three new species of Cladonia from Thailand. Drei neue Arten von Cladonia in Thailand. Sauteria 15: 15–19. [New: Cladonia homchantarae Ahti & Parnmen sp. nov. (also Indonesia and Cambodia), C. reticaulis Ahti & Parnmen sp. nov. and C. rudis Ahti & Parnmen sp. nov.; color photos on Appendix pp. I–II.] Allen, A. 2008. Lobaria pulmonaria and Teloschistes species in the Channel Islands. British Lichen Society Bulletin 102: 11–16. [Notes on recent collections.] Alstrup, V., M. Grube, J. Motiejūnaitė, A. Nordin & M. Zhurbenko. 2008. Lichenicolous fungi from the Skibotn area, Troms, Norway. Graphis Scripta 20(1): 1–8. [Report of 93 spp. with 11 new to Norway and 1 new to Greenland.] Aptroot, A. 2008. A new Scoliciosporum from Madagascar. Lichenologist 40(2): 119–122. [New: S. arachnoideum sp. nov.] ——— & F. Schumm. 2008. Key to Ramalina species known from Atlantic islands, with two new species from the Azores. Bestimmungsschlussel fur Ramalina Arten von den altantischen Inseln, mit zwei neuen Arten aus den Azoren. Sauteria 15: 21–57. [New: R. azorica sp. nov. and R. wirthii sp. nov. ‘‘... Ramalina subfarinacea is confirmed from the Canary Islands.’’ Key to 53 taxa from Iceland to the South Shetland Islands; black and white photographs are included for each species; color photograph of R. azorica is on Appendix p. II.] ———, L. Sparrius, S. LaGreca & F. Bungartz. 2008. Angiactis, a new crustose lichen genus in the Roccellaceae, with species from Bermuda, the Galapagos Islands and Australia. The Bryologist 111(3): 510–516. [New: Angiactis Aptroot & Sparrius gen. nov., A. bermudensis LaGreca sp. nov. (Bermuda), A. littoralis (Kantvilas) Aptroot & Sparrius comb. nov. (Tasmania and Western Australia), and A. spinicola Aptroot & Sparrius sp. nov. (Galapagos Islands).] Atienza, V. & D. L. Hawksworth. 2008. Lichenothelia renobalesiana sp. nov. (Lichenotheliaceae), for a lichenicolous ascomycete confused with Polycoccum opulentum (Dacampiaceae). Lichenologist 40(2): 87–96. [New: L. renobalesiana D. Hawksw. & V. Atienza sp. nov. on Verrucaria spp. from Spain and Great Britain. ‘‘The true P. opulentum is known only from the original collection on Polyblastia hyperborea from Sweden.] Awasthi, D. D. 2007. A Compendium of the Macrolichens from India, Nepal and Sri Lanka. Bishen Singh Mahendra Pal Singh, Dehra-Dun, India. 580 pp. [Treatment of 122 genera and 874 spp. with keys, synonyms, descriptions and notes; includes a list of 64 taxa reported but apparently now absent from the region. New: Flavocetrariella gen. nov., F. leucostigma (Lev.) comb. nov., F. melaloma (Nyl.) comb. nov., Lasallia freyana sp. et nom. nov., Hypotrachyna pindarensis (D. D. Awasthi & Singh) comb. nov., Hyperphyscia adglutinata var. pyrithocardia (Mull. Arg.) comb. nov., Physconia sikkimensis (Jatta) comb. nov., Pseudocyphellaria argyracea var. aspera (Lauer) comb. nov., P. diplomorpha (Mull Arg.) comb. nov., Rhizoplaca chrysoleuca var. australis (Poelt) comb. nov. and R. malanophthalma var. obscura (J. Steiner) comb. nov.] Baruffo, L., M. Piccotto & M. Tretiach. 2008. Intrathalline variation of chlorophyll a fluorescence emission in the epiphytic lichen Flavoparmelia caperata. The Bryologist 111(3): 455–462. [Study in Italy. ‘‘... all parameters were statistically higher in the marginal spots than in the central ones, suggesting that the level of photochemical activity is higher where the photobiont cells are more dense and younger.’’ Authors suggest that measuring spots for biomonitoring should be specifically selected.] Bennett, J. P. 2008. Discrimination of lichen genera and species using element concentrations. Lichenologist 40(2): 135–151. [Study of 16 element concentrations in 6 macrolichen species over 23 years in the Great Lakes region. * The cumulative database for this series is available in searchable form on the World Wide Web at http://www.nhm.uio.no/botanisk/bot-mus/ lav/sok_rll.htm. I owe special thanks to Bill Buck for providing copies of papers by other authors, which were otherwise unavailable to me, and to the cooperating authors who send reprints or electronic versions of their works to me for inclusion in this series.

Phylogenetic Analysis of Lichen-Forming Fungi Rhizoplaca Zopf from China Based on ITS Data and Morphology

A molecular phylogenetic analysis of Rhizoplaca melanophthalma, Rhizoplaca chrysoleuca, Rhizoplaca peltata and Rhizoplaca haydenii is presented based on the nuclear ribosomal internal transcribed spacer (ITS) regions and morphology. Rhizoplaca species were collected at 3400-3900 m in Tianshan Mountains, Xinjiang province, China. Rhizoplaca haydenii is reported for the first time in China. Maximum parsimony (MP) analysis of ITS sequences obtained from Tianshan Mountains samples and GenBank reveals that the evolution relationship of Rhizoplaca melanophthalma and Rhizoplaca chrysoleuca is closer to each other than to Rhizoplaca peltata, and Rhizoplaca haydenii showed closer relatedness to Rhizoplaca melanophthalma. When the four species groups from Tianshan Mountains were analyzed alone through the neighbour-joining (NJ) and minimum evolution method, we obtained the same result. The morphology analysis of Rhizoplaca Zopf which reveals the pruinose discs and apothecial discs of species did not show convincing evidences to prove phylogenetic relationship among Rhizoplaca species In our study, the result further proved that Rhizoplaca should be rejected as a genus separate from Lecanora.

Phylogenetic Relations of Rhizoplaca Zopf. from Anatolia Inferred from ITS Sequence Data

Like many lichen-forming fungi, species of the genus Rhizoplaca have wide geographical distributions, but studies of their genetic variability are limited. The information about the ITS rDNA sequences of three species of Rhizoplaca from Anatolia was generated and aligned with other species from other countries and also with the data belonging to Lecanora species. The examined species were collected from the volcanic rocks of Mount Erciyes which is located in the middle of Anatolia (Turkey). The sequence data aligned with eight other samples of Rhizoplaca and six different species of Lecanora were obtained from GenBank. The results support the concept maintained by Arup and Grube (2000) that Rhizoplaca may not be a genus separate from Lecanora. According to the phylogenetic tree, Rhizoplaca melanopthalma from Turkey with two different samples of R. melanopthalma from Arizona (AF159929, AF159934) and a sample from Austria formed a group under the same branch. R. peltata and R. chrysoleuca samples from Anatolia located in two other branches of the tree formed sister groups with the samples of the same species from different countries. Although R. peltata remained on the same branch with other samples of the same species from other countries it was placed in a different branch within the group. When the three species from Anatolia were considered alone, it was noticed that Rhizoplaca melanopthalma and Rhizoplaca peltata are phylogenetically closer to each other than Rhizoplaca chrysoleuca; the morphological characteristics also support this result.

Determination of Usnic Acid in Some Rhizoplaca Species from Middle Anatolia and their Antimicrobial Activities

Three species of lichens, Rhizoplaca chrysoleuca (Sm.) Zopf, Rhizoplaca melanopthalma (DC.) Leuckert & Poelt and Rhizoplaca peltata Ramonds Leuckert, were collected from middle Anatolia, Erciyes Mountain (Kayseri) in Turkey. Their usnic acid amounts were determined by HPLC in acetone extracts. In addition, antimicrobial activities of these extracts were determined against Escherichia coli (ATCC 35218), Enterococcus faecalis (RSKK 508), Proteus mirabilis (Pasteur Ens. 235), Staphylococcus aureus, Bacillus subtilis, Bacillus megaterium and Pseudomonas aeruginosa. It was shown that, as the usnic acid amount increased, the antimicrobial activities increased too. The usnic acid contents of Rhizoplaca species varied between 0.19-4.0% dry weight.

A study of the genetic variability of Rhizoplaca chrysoleuca using DNA sequences and secondary metabolic substances

Specimens of Rhizoplaca chrysoleuca from Mount Wuling can be divided into two distinct groups based on obvious differences in morphological characters. Here we investigated 26 specimens of R. chrysoleuca from Mount Wuling, 10 specimens of this species from other areas and seven specimens of other Rhizoplaca species by analyzing morphology, chemistry and genetics. Nine chemotypes were detected among the specimens of R. chrysoleuca from Mount Wuling, and five of them were reported for the first time. Based on the ITS phylogenetic analysis, the chemotypes and the insertion distribution patterns in SSU rDNA, the samples of R. chrysoleuca from Mount Wuling were grouped in two distinct clades corresponding to two phenotypic groups and no gene flow was detected between these two groups. Our results establish all individuals of Rhizoplaca chrysoleuca are conspecific although some populations have been isolated on Mount Wuling, indicating that they are in the process of speciation. Our study also reveals that the relationships between genotypes and chemotypes are complicated and should be avoided, and we instead recommend using single individuals or few individuals from the same site to represent the population or whole species in systematics study. The results also indicate that Rhizoplaca chrysoleuca might provide a good model for studying the speciation of saxicolous lichenized fungi.

A study of the genetic variability of Rhizoplaca chrysoleuca using DNA sequences and secondary metabolic substances

Specimens of Rhizoplaca chrysoleuca from Mount Wuling can be divided into two distinct groups based on obvious differences in morphological characters. Here we investigated 26 specimens of R. chrysoleuca from Mount Wuling, 10 specimens of this species from other areas and seven specimens of other Rhizoplaca species by analyzing morphology, chemistry and genetics. Nine chemotypes were detected among the specimens of R. chrysoleuca from Mount Wuling, and five of them were reported for the first time. Based on the ITS phylogenetic analysis, the chemotypes and the insertion distribution patterns in SSU rDNA, the samples of R. chrysoleuca from Mount Wuling were grouped in two distinct clades corresponding to two phenotypic groups and no gene flow was detected between these two groups. Our results establish all individuals of Rhizoplaca chrysoleuca are conspecific although some populations have been isolated on Mount Wuling, indicating that they are in the process of speciation. Our study also reveals that the relationships between genotypes and chemotypes are complicated and should be avoided, and we instead recommend using single individuals or few individuals from the same site to represent the population or whole species in systematics study. The results also indicate that Rhizoplaca chrysoleuca might provide a good model for studying the speciation of saxicolous lichenized fungi.

The amounts Fe, Ba, Sr, K, Ca and Ti in some lichens growing in Erzurum province (Turkey)

The amounts of Fe, Ba, Sr, K, Ca and Ti were determined qualitatively and quantitatively by using energy-dispersive X-ray fluorescence in eight lichen species, Pinus sylvestris, rock and soil in district of Erzurum province (Turkey). Lichen species were Cetraria pinastri (Scop.) Gray, Dermatocarpon miniatum (L.) W. Mann, Lecanora muralis (Schreb.) Rabenh., Pseudevernia furfuracea (L.) Zopf., Ramalina capitata (Ach.) Nyl., Rhizoplaca chrysoleuca (sm.) Zopf., Rhizoplaca melanophthalma (DC.) Leuckert & Poelt, and Xanthoparmelia somloensis (Gyeln.) Hale. The standard addition method was used for the determination of the concentration of Fe, Ba, Sr, K, Ca and Ti. The experimental setup consists of a Si(Li) detector with a resolution of 147 eV at 5.9 keV and annular 55Fe and 241Am radioactive sources. By the use of intersite, interelement and interspecies comparisons, it is concluded that some metals within the thalli of lichens in Erzurum province may reach high levels even when these plants are growing in rural and isolated sites.

The amounts Fe, Ba, Sr, K, Ca and Ti in some lichens growing in Erzurum province (Turkey)

The amounts of Fe, Ba, Sr, K, Ca and Ti were determined qualitatively and quantitatively by using energy-dispersive X-ray fluorescence in eight lichen species, Pinus sylvestris , rock and soil in district of Erzurum province (Turkey). Lichen species were Cetraria pinastri (Scop.) Gray, Dermatocarpon miniatum (L.) W. Mann, Lecanora muralis (Schreb.) Rabenh., Pseudevernia furfuracea (L.) Zopf., Ramalina capitata (Ach.) Nyl., Rhizoplaca chrysoleuca (sm.) Zopf., Rhizoplaca melanophthalma (DC.) Leuckert & Poelt, and Xanthoparmelia somloensis (Gyeln.) Hale. The standard addition method was used for the determination of the concentration of Fe, Ba, Sr, K, Ca and Ti. The experimental setup consists of a Si(Li) detector with a resolution of 147 eV at 5.9 keV and annular 55 Fe and 241 Am radioactive sources. By the use of intersite, interelement and interspecies comparisons, it is concluded that some metals within the thalli of lichens in Erzurum province may reach high levels even when these plants are growing in rural and isolated sites.

Five new species of lichenicolous conidial fungi from Spain

Five new species of lichenicolous conidial fungi from Spain are described. The genus Lichenohendersonia Calatayud &amp; Etayo gen.nov. is introduced to accommodate three new coelomycetes: Lichenohendersonia squamarinae Calatayud &amp; Etayo sp.nov. (on Squamarina lentigera), Lichenohendersonia uniseptata Etayo &amp; Calatayud sp.nov. (on Parmelina tiliacea), and Lichenohendersonia varians Calatayud &amp; Etayo sp.nov. (type on Rhizoplaca chrysoleuca, but also occurring on other saxicolous crustose lichens). Two further species are also described: Phoma aggregata Calatayud &amp; Etayo sp.nov. (on Diploschistes ocellatus), with numerous and densely aggregated pycnidia, and Feltgeniomyces dichotomus Etayo &amp; Calatayud sp.nov., a sporodochial fungus occurring on Physcia biziana and Heterodermia sp. All these taxa are known only from the Iberian Peninsula, except F. dichotomus, which is also reported from Colombia. Keys to the known Feltgeniomyces and Lichenohendersonia species are provided.Key words: Lichenicolous fungi, deuteromycetes, Feltgeniomyces, Lichenohendersonia, Phoma, Spain.

IsRhizoplaca(Lecanorales, lichenized Ascomycota) a monophyletic genus?

Rhizoplaca Zopf is a genus characterized by an umbilicate thallus with an upper and a lower cortex, as well as a cupulate hypothecium. It has been considered to be related to Lecanora Ach., the type genus of the Lecanoraceae and, in particular, to the lobate species of this genus. The phylogeny of Rhizoplaca, the monotypic Arctopeltis thuleana Poelt, and a number of representatives of different groups of Lecanora is studied, using sequences from the nuclear ribosomal internal transcribed spacer (ITS) regions. The results suggest an origin for Rhizoplaca species within the large genus Lecanora. A well-supported monophyletic assemblage includes the umbilicate type species Rhizoplaca melanophthalma (DC.) Leuck. &amp; Poelt, the lobate Lecanora novomexicana H. Magn., and five vagrant Rhizoplaca species. Rhizoplaca chrysoleuca (Sm.) Zopf and Rhizoplaca subdicrepans (Nyl.) R. Sant. form a separate well-supported group and Rhizoplaca peltata (Ram.) Leuck. &amp; Poelt is more closely related to Lecanora muralis (Schreb.) Rabenh. Together with data on secondary chemistry, the results show that the umbilicate thallus with a lower and an upper cortex, as well as apothecia with a cupulate hypothecium found in Rhizoplaca and A. thuleana, have developed several times in independant lineages in Lecanora. The thallus morphology in lecanoroid lichens is highly variable and does not necessarily reflect phylogenetic relationships.Key words: Rhizoplaca, Lecanora, Lecanorales, phylogeny, ITS.

Molecular sizes of lichen ice nucleation sites determined by gamma radiation inactivation analysis

It has previously been shown that some species of lichen fungi contain proteinaceous ice nuclei which are active at temperatures as warm as −2 °C. This experiment was undertaken to determine the molecular sizes of ice nuclei in the lichen fungus Rhizoplaca chrysoleuca and to compare them to bacterial ice nuclei from Pseudomonas syringae. Gamma radiation inactivation analysis was used to determine molecular weights. Radiation inactivation analysis is based on target theory, which states that the likelihood of a molecule being inactivated by gamma rays increases as its size increases. Three different sources of ice nuclei from the lichen R. chrysoleuca were tested: field-collected lichens, extract of lichen fungus, and a pure culture of the fungus R. chrysoleuca. P. syringae strain Cit7 was used as a source of bacterial ice nuclei. Samples were lyophilized, irradiated with gamma doses ranging from 0 to 10.4 Mrads, and then tested for ice nucleation activity using a droplet-freezing assay. Data for all four types of samples were in rough agreement; sizes of nucleation sites increased logarithmically with increasing temperatures of ice nucleation activity. Molecular weights of nucleation sites active between −3 and −4 °C from the bacteria and from the field-collected lichens were approximately 1.0 × 10 6 Da. Nuclei from the lichen fungus and in the lichen extract appeared to be slightly smaller but followed the same log-normal pattern with temperature of ice nucleation activity. The data for both the bacterial and lichen ice nuclei are in agreement with ice nucleation theory which states that the size of ice nucleation sites increases logarithmically as the temperature of nucleation increases linearly. This suggests that although some differences exist between bacterial and lichen ice nucleation sites, their molecular sizes are quite similar.

Characterization of biological ice nuclei from a lichen

Biological ice nuclei (active at approximately -4 degrees C) were extracted from cells of the lichen Rhizoplaca chrysoleuca by sonication. Sensitivity to proteases, guanidine hydrochloride, and urea showed these nuclei to be proteinaceous. The nuclei were relatively heat stable, active from pH 1.5 to 12, and active without lipids, thereby demonstrating significant differences from bacterial ice nuclei.

Biological Ice Nucleation Activity in Lichen Mycobionts and Photobionts

AbstractAxenic cultures of lichen mycobionts and photobionts were assayed for biological ice nucleation activity (INA), a characteristic which has recently been discovered in some species of lichens collected from nature. Of 14 species of mycobionts, five showed nuclei active at −5°C or warmer, while none of the 13 photobionts tested had INA at that temperature. It appears that biological ice nuclei in lichens are produced primarily by the mycobiont. Rhizoplaca chrysoleuca had the greatest INA. Other lichen fungi showing warm temperature INA were Cladonia boryi, Cladonia rangiferina, Lecanora dispersa, and Pertusaria flavicans. Lichen INA may be involved in moisture uptake and/or frost protection.