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| 3. |
- Dahlkild, Åsa, 1976-
(författare)
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Phylogenetic and ecological studies in lichenology : including studies of both mycobiont and photobiont
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this thesis different aspects in lichens are investigated, namely, the phylogeny of mycobiont and photobiont, and ecology in the form of species richness of certain habitats of the Uppland province, Sweden.Analyses of ITS sequences of the lichenized fungi genus Roccella (Roccellaceae) provide an intrageneric topology of the genus with emphasis on the European, Mediterranean and Macaronesian species. One species, Roccella elisabethae Tehler, is described and a key to the Macaronesian and European species is provided. Sequences from five Roccella species are new. One significant result is that the Macaronesian species constitute a monophyletic group.Newly designed algal-specific primers were used to amplify the ribosomal ITS region from 25 photobiont specimens from five lichenized fungal species of the family Physciaceae (Lecanorales). Trebouxia impressa was present in all mycobionts except Anaptychia ciliaris, which instead was associated with Trebouxia arboricola. A phylogeny for the photobiont, T. impressa, was compared to a phylogeny of the corresponding mycobionts. The general similarity of the mycobiont and photobiont trees may indicate a coevolutionary history. The ribosomal SSU region and the rbcL gene were sequenced from total DNA extracts from thalli of 8 species of Siphula (Icmadophilaceae) and 6 species of Parasiphula (Coccotremataceae). All specimens were found to have Elliptochloris bilobata in a wider sense as photobiont, indicating independent accession of photobionts for the two mycobiont genera.The epiphytic lichen flora on Fraxinus exelcior and Acer platanoides in lanes and two types of wooded meadows were investigated in Uppland, Sweden. Altogether 129 lichen species were found, five of which are listed in the Swedish Red List of threatened species. The species richness was affected by substrate, habitat, and distance to dust source. Lanes had the highest species richness, and Fraxinus excelsior had higher species richness than Acer platanoides.
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| 7. |
- Ertz, Damien, et al.
(författare)
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Remarkable cases of parallel evolution of the placodioid thallus growth form in the Lecanographaceae (Arthoniales) with the description of a new species of Alyxoria from Mexico
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Ingår i: The Lichenologist. - 0024-2829 .- 1096-1135.
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Tidskriftsartikel (refereegranskat)abstract
- The new species Alyxoria sierramadrensis is described from Mexico where it inhabits limestone rocks. The lichen developing from this fungus is characterized by a placodioid to subfoliose thallus with a white pruinose surface; rounded to shortly elongated ascomata with a black epruinose margin and a widely exposed, white pruinose hymenial disc; hyaline, 3-septate ascospores,17–25 × 7–9 μm; the presence of anthraquinones rendering the medulla orange. Phylogenetic analyses of nuLSU, mtSSU and RPB2 sequences place this species in the genus Alyxoria (Lecanographaceae). This generic affiliation is surprising because all known Alyxoria species have a crustose thallus. Lecanographaceae mainly includes species without a thallus (lichenicolous taxa) or with a thin crustose thallus, the only exception being Simonyella variegata with a fruticose thallus. The new species belongs to the Alyxoria ochrocheila subgroup, which includes lichens also frequently known to have anthraquinones, white pruinose hymenial discs and 3-septate ascospores. Phylogenetic analyses further determined the systematic position of the monotypic genus Phoebus. This genus, considered as an Arthoniales of uncertain family affiliation, is shown to belong to the Lecanographaceae. With its placodioid thallus, it is another example of a lichenized fungus with a deviating morphology in thallus structure for the family, increasing the number of remarkable cases of parallel evolution of lichen growth forms within the Arthoniales. Phoebus hydrophobius is newly recorded for Mexico.
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| 11. |
- Häfner, Sophia J., et al.
(författare)
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Ribosomal RNA 2′-O-methylation dynamics impact cell fate decisions
- 2023
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Ingår i: Developmental Cell. - 1534-5807. ; 58:17, s. 9-1609
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Tidskriftsartikel (refereegranskat)abstract
- Translational regulation impacts both pluripotency maintenance and cell differentiation. To what degree the ribosome exerts control over this process remains unanswered. Accumulating evidence has demonstrated heterogeneity in ribosome composition in various organisms. 2′-O-methylation (2′-O-me) of rRNA represents an important source of heterogeneity, where site-specific alteration of methylation levels can modulate translation. Here, we examine changes in rRNA 2′-O-me during mouse brain development and tri-lineage differentiation of human embryonic stem cells (hESCs). We find distinct alterations between brain regions, as well as clear dynamics during cortex development and germ layer differentiation. We identify a methylation site impacting neuronal differentiation. Modulation of its methylation levels affects ribosome association of the fragile X mental retardation protein (FMRP) and is accompanied by an altered translation of WNT pathway-related mRNAs. Together, these data identify ribosome heterogeneity through rRNA 2′-O-me during early development and differentiation and suggest a direct role for ribosomes in regulating translation during cell fate acquisition.
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| 12. |
- Ivarsson, Magnus, et al.
(författare)
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Fossilized fungi in subseafloor Eocene basalts.
- 2012
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Ingår i: Geology. - 0091-7613. ; 40:2, s. 163-166
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Tidskriftsartikel (refereegranskat)abstract
- The deep biosphere of subseafl oor basalts is thought to consist of mainly prokaryotes (bacteria and archaea). Here we report fossilized fi lamentous microorganisms from subseafl oor basalts interpreted as fossilized fungal hyphae, probably Dikarya, rather than fossilized prokaryotes. The basalts were collected during the Ocean Drilling Program Leg 197 at the Emperor Seamounts, North Pacifi c Ocean, and the fossilized fungi are observed in carbonate-fi lled veins and vesicles in samples that represent a depth of ~150 m below the seafl oor. Three-dimensional visualizations using synchrotron-radiation X-ray tomographic microscopy show characteristic fungal morphology of the mycelium-like network, such as frequent branching, anastomosis, and septa. Possible presence of chitin in the hypha walls was detected by staining with Wheat Germ Agglutinin conjugated with Fluorescein Isothiocyanate and examination using fl uorescence microscopy. The presence of fungi in subseafl oor basalts challenges the present understanding of the deep subseafl oor biosphere as being exclusively prokaryotic.
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| 13. |
- Ivarsson, Magnus, et al.
(författare)
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Zygomycetes in Vesicular Basanites from Vesteris Seamount, Greenland Basin - A New Type of Cryptoendolithic Fungi
- 2015
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Ingår i: PLoS One. - : Public Library of Science (PLoS). ; 10:7
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Tidskriftsartikel (refereegranskat)abstract
- Fungi have been recognized as a frequent colonizer of subseafloor basalt but a substantial understanding of their abundance, diversity and ecological role in this environment is still lacking. Here we report fossilized cryptoendolithic fungal communities represented by mainly Zygomycetes and minor Ascomycetes in vesicles of dredged volcanic rocks (basa- nites) from the Vesteris Seamount in the Greenland Basin. Zygomycetes had not been reported from subseafloor basalt previously. Different stages in zygospore formation are documented in the studied samples, representing a reproduction cycle. Spore structures of both Zygomycetes and Ascomycetes are mineralized by romanechite-like Mn oxide phases, indicating an involvement in Mn(II) oxidation to form Mn(III,VI) oxides. Zygospores still exhibit a core of carbonaceous matter due to their resistance to degradation. The fungi are closely associated with fossiliferous marine sediments that have been introduced into the vesicles. At the contact to sediment infillings, fungi produced haustoria that penetrated and scavenged on the remains of fragmented marine organisms. It is most likely that such marine debris is the main carbon source for fungi in shallow volcanic rocks, which favored the establishment of vital colonies.
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| 14. |
- Kantvilas, Gintaras, et al.
(författare)
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The strange case of Ocellomma rediuntum (Arthoniales: Roccellaceae) in Australia: a remarkably disjunct lichen
- 2020
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Ingår i: The Lichenologist. - 0024-2829 .- 1096-1135. ; 52, s. 187-195
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Tidskriftsartikel (refereegranskat)abstract
- The new combination Ocellomma rediuntum (Stizenb. ex Hasse) Kantvilas, Gueidan & Tehler is proposed, supported by morphological, anatomical and molecular data. Hitherto known only from the Californian coast, this species is here recorded for Kangaroo Island (South Australia), Victoria and Tasmania. It is described and illustrated from Australian collections. The ecology of the species and its remarkable distribution are discussed.
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| 15. |
- Lin, Lexin, et al.
(författare)
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On the perceived usefulness of risk descriptions for decision-making in disaster risk management
- 2015
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Ingår i: Reliability Engineering & System Safety. - : Elsevier BV. - 0951-8320. ; 142, s. 48-55
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Tidskriftsartikel (refereegranskat)abstract
- Managing risk using an “all-hazards” and “whole of society”-approach involves extensive communication of risk descriptions among many stakeholders. In the present study we investigate how professionals working with disaster risk management in such contexts perceive the usefulness of different descriptions of risk. Empirical data from the Swedish disaster risk management system were used in an attempt to investigate the aspects of a risk description that affect its usefulness (as perceived by professionals). Thirty-three local municipal risk and vulnerability assessments (RVA documents) produced in the region of Scania in 2012 were analyzed in terms of six variables. The documents were then ranked by professionals based on their perceived usefulness for decision-making. Statistical analysis was conducted to identify any possible correlations between the overall ranking of the usefulness of the municipal RVA:s and each of the variables. We conclude that the way the likelihood and consequences of scenarios are described influence the perceived usefulness of a risk description. Furthermore, whether descriptions of scenarios are included in a risk description or not, and whether background information concerning the likelihood of scenarios are included also influence perceived usefulness of risk descriptions.
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| 17. |
- Lohtander, Katileena, et al.
(författare)
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New entities in Physcia aipolia-P-caesia group (Physciaceae, Ascomycetes) : an analysis based on mtSSU, ITS, group I intron and betatubulin sequences
- 2009
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Ingår i: Annales Botanici Fennici. - 0003-3847 .- 1797-2442. ; 46:1, s. 43-53
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Tidskriftsartikel (refereegranskat)abstract
- We have revisited the phylogenetic evaluation of the Physcia aipolia-P. caesia lichen group (sect. Caesiae; Physciaceae, Lecanorales) in order to investigate whether new sequence data and extensive sampling can help us to understand the phylogenetic relationships in that group. We combined partial mtSSU DNA data with two previously used nuclear gene regions (betatubulin, ITS) and a group I intron. We also compared the resulting phylogenies with chemical and morphological characters. Altogether 52 specimens of the P. aipolia-P. caesia group were analysed. Direct optimization of the molecular data revealed several well-supported groups. Our results essentially agreed with those of the earlier studies, and we were able to confirm the independent taxonomic status of some controversial morphotaxa. We also discovered at least two distinct clades that potentially represent species new to science. A new nomenclatural combination, Physcia alnophila (Vain.) Loht., Moberg, Myllys & Tehler, is proposed.
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| 19. |
- Miranda-Gonzále, Ricardo, et al.
(författare)
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Roccella ramitumidula (Roccellaceae), a new species from the tropical dry forest of Mexico
- 2022
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Ingår i: Bryologist. ; 125:3, s. 477-484
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Tidskriftsartikel (refereegranskat)abstract
- The new species Roccella ramitumidula is described from a tropical dry forest in the Pacific Coast of Mexico. The new species is characterized by fertile thalli, saxicolous habit, irregularly swollen branches and erythrin and lecanoric acid as lichen products. It differs from R. decipiens by its narrower and longer ascospores, irregularly swollen branches, uneven surface, and smaller branches. Sequences of the genetic markers ITS, nuLSU and RPB2 from the new species were added to a phylogenetic tree based on four genetic markers that included all the Roccella species known for the Americas. The biogeography and ecology of the species is discussed. We reported R. gracilis for the first time for the state of Jalisco, Mexico.
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| 20. |
- Palmqvist, Kristina, et al.
(författare)
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CO2 exchange and thallus nitrogen across 75 contrasting lichen associations from different climate zones
- 2002
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Ingår i: Oecologia. - : Springer Science and Business Media LLC. - 0029-8549 .- 1432-1939. ; 133:3, s. 295-306
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Tidskriftsartikel (refereegranskat)abstract
- Aiming to investigate whether a carbon-to-nitrogen equilibrium model describes resource allocation in lichens, net photosynthesis (NP), respiration (R), concentrations of nitrogen (N), chlorophyll (Chl), chitin and ergosterol were investigated in 75 different lichen associations collected in Antarctica, Arctic Canada, boreal Sweden, and temperate/subtropical forests of Tenerife, South Africa and Japan. The lichens had various morphologies and represented seven photobiont and 41 mycobiont genera. Chl a, chitin and ergosterol were used as indirect markers of photobiont activity, fungal biomass and fungal respiration, respectively. The lichens were divided into three groups according to photobiont: (1) species with green algae, (2) species with cyanobacteria, and (3) tripartite species with green algal photobionts and cyanobacteria in cephalodia. Across species, thallus N concentration ranged from 1 to 50 mg g(-1) dry wt., NP varied 50-fold, and R 10-fold. In average, green algal lichens had the lowest, cyanobacterial Nostoc lichens the highest and tripartite lichens intermediate N concentrations. All three markers increased with thallus N concentration, and lichens with the highest Chl a and N concentrations had the highest rates of both P and R. Chl a alone accounted for ca. 30% of variation in NP and R across species. On average, the photosynthetic efficiency quotient [K-F=(NPmax+R)/R)] ranged from 2.4 to 8.6, being higher in fruticose green algal lichens than in foliose Nostoc lichens. The former group invested more N in Chl a and this trait increased NPmax while decreasing R. In general terms, the investigated lichens invested N resources such that their maximal C input capacity matched their respiratory C demand around a similar (positive) equilibrium across species. However, it is not clear how this apparent optimisation of resource use is regulated in these symbiotic organisms.
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| 21. |
- Perlmutter, Gary B, et al.
(författare)
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Biatora akompsa is found to be a disjunct North American species of Pentagenella (Opegraphaceae) through Molecular Phylogenetic Analysis
- 2020
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Ingår i: The Bryologist. - 0007-2745 .- 1938-4378. ; 123:3, s. 502-516
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Tidskriftsartikel (refereegranskat)abstract
- Historical and recent material of Bacidia akompsa (basionym: Biatora akompsa) was studied to determine the taxonomic position of this crustose lichen, prompted by the appearance of the provisional name ‘‘Lecanactis akompsa (Tuck.) ined.’’ in multiple online lichen databases and checklists. Initial morphological assessment of verified material confirmed B. akompsa as a member of Arthoniales but distinct from Lecanactis by having epruinose ascomata with a thin exciple open below the hymenium; a pale, K/Iþ violet to deep blue hypothecium; and ascospores with a gelatinous sheath. Molecular phylogenetic analysis of specimens recently collected near the type locality revealed B. akompsa to be nested within the genus Pentagenella in Opegraphaceae. The same placement was found using phenotype-based phylogenetic binning with 37 morphological, anatomical and chemical characters. The new combination Pentagenella akompsa is proposed and the species represents the first North American member of this genus, otherwise known only from Chile and Peru. Therefore, our results reveal the genus Pentagenella to have a remarkably disjunct distribution between North and South America. Several specimens previously labeled as Bacidia, Biatora, or Lecanactis akompsa were found to be misidentifications, narrowing the range of P. akompsa to coastal California, where it is found on two coastal conifer species that are (like P. akompsa itself) narrowly endemic and of conservation concern.
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| 22. |
- Poengsungnoen, Vasun, et al.
(författare)
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Phylogenetic analysis reveals two morphologically unique new species in the genera Astrochapsa and Nitidochapsa (lichenized Ascomycota Graphidaceae)
- 2014
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Ingår i: Phytotaxa. - : Magnolia Press. - 1179-3163 .- 1179-3155. ; 189, s. 268-281
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Tidskriftsartikel (refereegranskat)abstract
- Graphidaceae is the largest family of tropical crustose lichens, with nearly 2,400 known species, and exhibits a large diversity of ascoma morphologies. Ascomata that open by triangular marginal lobules that become recurved to form geaster-like fruiting bodies, so-called chroodiscoid ascomata, were recently shown to have evolved independently several times within the family. A special type of such ascomata is the gyrotremoid form in which the hymenium and excipulum are organized in concentric rings. In the present study, we address the phylogenetic position of two chroodiscoid species collected in Thailand that form aggregate or gyrotremoid, chroodiscoid ascomata, using a molecular phylogeny of nuclear LSU and mitochondrial SSU rDNA sequences of 92 Graphidaceae. Our morphological, chemical and phylogenetic analyses show that one species is an undescribed species in the genus Astrochapsa, here newly described as A. kalbii Poengsungnoen, Lücking & Lumbsch, with a unique, gyrotremoid ascoma morphology. The second species belongs in the recently established genus Nitidochapsa, which is a close relative of Ocellularia, and is here described as new species N. siamensis Poengsungnoen, Lücking & Lumbsch. Based on these findings, three further new combinations are proposed in the genus Nitidochapsa, viz. N. aggregata (Hale) Poengsungnoen, Lücking & Lumbsch, N. phlyctidea (Vain.) Lücking & Lumbsch, and N. stictoides (Leight.) Tehler, Lücking & Lumbsch. A key to all five species is presented.
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| 24. |
- Sonesson, Mats, et al.
(författare)
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A comparison of the physiology, anatomy and ribosomal DNA in alpine and subalpine populations of the lichen Nephroma arcticum – the effects of an eight-year transplant experiment
- 2007
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Ingår i: The Bryologist. - 0007-2745 .- 1938-4378. ; 110:2, s. 244-253
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Tidskriftsartikel (refereegranskat)abstract
- Thalli of Nephroma arcticum were transplanted between and within a high-elevation alpine heath (1100 m) and a low-elevation subalpine mountain birch forest (380 m) in northern Swedish Lapland and harvested after eight years. Statistically significant differences (P < 0.05) were found between control samples for dark respiration rates, photon use efficiencies (apparent quantum yields) and light compensation points (all were higher in the high-altitude population). The following traits were significantly affected by transplanting: (1) epicortex thickness, (2) upper cortex thickness in the low-altitude population, (3) maximum photosynthetic rates, (4) dark respiration rates and (5) light compensation point. Of these malleable traits, all reduce the differences between the controls although there seems to be over-compensation in maximum net photosynthesis and under-compensation in dark respiration rate of the low-altitude population. Conservative traits, i.e., those that did not change significantly with transplantation were: (1) thallus thickness, (2) algal layer thickness, (3) algal cell diameter and (4) light saturation level. Small, yet significant differences in anatomy and physiology suggest that an ecotypic differentiation was established although the two internal transcribed DNA spacers ITS 1 and ITS 2 showed no corresponding variation between the populations.
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| 25. |
- Sparrius, Laurens B, et al.
(författare)
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New species of Enterographa and Fulvophyton from Malaysia and Mexico
- 2020
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Ingår i: Plant and Fungal Systematics. ; 65:1, s. 185-188
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Tidskriftsartikel (refereegranskat)abstract
- new species of Enterographa (Arthoniales: Roccellaceae) is described. E. kina- baluensis from Kota Kinabalu is characterized by the presence of punctiform soralia and norstictic acid. The saxicolous Fulvophyton serusiauxii is described from coastal Mexico and differs from the corticolous F. klementii in having much smaller ascospores.
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