bluuebunny/crossref_metadata_2025 huggingface dataset:
NONCOMMUTATIVE FIELD THEORY AND THE DYNAMICS OF QUANTUM HALL FLUIDS
Authors: BARBÓN J. L. F. , PAREDES A.
Published: September 2002

We study the spectrum of density fluctuations of fractional Hall fluids in the context of the noncommutative hydrodynamical model of Susskind. We show that, within the weak-field expansion, the leading correction to the noncommutative Chern–Simons Lagrangian (a Maxwell term in the effective action), destroys the incompressibility of the Hall fluid due to strong UV/IR effects at one loop. We speculate on possible relations of this instability with the transition to the Wigner crystal, and conclude that calculations within the weak-field expansion must be carried out with an explicit ultraviolet cutoff at the noncommutativity scale.

We point out that the noncommutative dipoles exactly match the spatial structure of the Halperin–Kallin quasiexcitons. Therefore, we propose that the noncommutative formalism must describe accurately the spectrum at very large momenta, provided no weak-field approximations are made. We further conjecture that the noncommutative open Wilson lines are "vertex operators" for the quasiexcitons.
MORE ON PHASE STRUCTURE OF NONLOCAL 2D GENERALIZED YANG–MILLS THEORIES (nlgYM2's)
Authors: SAAIDI KH. , SETARE M. R.
Published: September 2002

We study the phase structure of nonlocal two-dimensional generalized Yang–Mills theories (nlgYM2) and it is shown that all order of ϕ2k model of these theories has phase transition only on compact manifold with g = 0 (on sphere), and the order of phase transition is 3. Also it is shown that the [Formula: see text] model of nlgYM2 has third order phase transition on any compact manifold with [Formula: see text], and has no phase transition on the sphere.
GALVANOMAGNETIC EFFECTS AND ELECTRONIC SPECIFIC HEAT OF BULK La2-xBaxCu1-yZnyO4+d
Authors: ILONCA G. , POP A. V. , ILONCA M. , MACOCIAN E. , JURCUT T. , STIUFIUC R. , TOMA V.
Published: September 2002

The samples of bulk La 2-x Ba x Cu 1-y Zn y O 4+d were prepared by conventional solid state reaction method and have been investigated using electrical resistivity, Seebeck coefficient, Hall coefficient and electronic specific heat measurements over the temperature range between 4.2 K and 300 K in magnetic fields up to 5 T. The samples with y = 0 and d = 0 showed superconductivity for x between 0.055 and 0.30. The critical temperature, the Hall and Seebeck coefficients depend strongly on Zn contents. The phonon specific heat and electronic specific heat have been extracted from the total specific heat, where anomalous x, y and T dependence related to the so-called 1/8 anomaly or the "stripe order" is observed. Zn-doping effect or the behavior γ (T) = Cel/T suggest that large range stripe order and the fluctuating "stripe" suppress the singlet formation and pseudo-gap.
FIRST-ORDER TRANSITION, FINITE-ISOLATED SYSTEM AND MICROCANONICAL MONTE CARLO SIMULATIONS
Authors: OTA SMITA , OTA SNEHADRI BIHARI
Published: September 2002

We have investigated the first-order transition in the classical two-dimensional (2D) extended XY-spin model using Monte Carlo simulations. The simulations have been carried out on a system with 100 spins in the microcanonical ensemble, which represents a finite-isolated system. The energy as a function of temperature is found to exhibit a 'S'-shape at the first-order transition. We conclude that the observed phenomena at the first-order transition should be interpreted as the equilibrium response of a finite-isolated system.
SMART SENSOR: AN ON-BOARD IMAGE PROCESSING SYSTEM FOR REAL-TIME REMOTE SENSING
Authors: YOU JANE , ZHANG DAVID
Published: September 2002

This paper presents a new approach to smart sensor system design for real-time remote sensing. A combination of techniques for image analysis and image compression is investigated. The proposed algorithms include: (1) a fractional discrimination function for image analysis, (2) a comparison of effective algorithms for image compression, (3) a pipeline architecture for parallel image classification and compression on-board satellites, and (4) a task control strategy for mapping image computing models to hardware processing elements. The efficiency and accuracy of the proposed techniques are demonstrated throughout system simulation.
IMAGE RESTORATION BASED ON GENERALIZED FINITE AUTOMATA ENCODED EDGE PRESERVING REGULARIZATION
Authors: BAO PAUL , HONG SUNG-WAI
Published: September 2002

We present an edge preserving regularization scheme for the restoration of degraded images compressed by the lossy compression method based on Generalized Finite Automata edge encoding and the Iterative Constrained Least Square Regularization technique. In this scheme, the degraded image reconstructed from lossy image compressions is treated as the input to the image restoration process. The edge information extracted from the source image is utilized as a priori knowledge for the subsequent reconstruction. In order to compromise the overall bit rate incurred by the additional edge information, a generalized finite automata encoding technique is adopted to encode the bit-planes of the edge image. The generalized finite automata method ensures an efficient and adaptive image-independent encoding of the edge image. The experiment has shown that the proposed scheme could significantly improve both the objective and subjective quality of the reconstructed image over that of the set partitioning in hierarchical trees by recovering more image details and edge structures under the same bit rates.
Tumor necrosis factor–related apoptosis-inducing ligand induces monocytic maturation of leukemic and normal myeloid precursors through a caspase-dependent pathway
Authors: Secchiero Paola , Gonelli Arianna , Mirandola Prisco , Melloni Elisabetta , Zamai Loris , Celeghini Claudio , Milani Daniela , Zauli Giorgio
Published: September 2002

Treatment of the human HL-60 cell line with tumor necrosis factor (TNF)–related apoptosis-inducing ligand (TRAIL) resulted in rapid (6-24 hours) cytotoxicity associated with progressive maturation of the surviving cells along the monocytic lineage. The occurrence of monocytic maturation was demonstrated by a significant increase of both CD14 and CD11b surface expression, the acquisition of morphologic features typical of mature monocytes, and phagocytic capacity in TRAIL-treated cultures. By using selective pharmacologic inhibitors, it was possible to demonstrate that activation of the caspase cascade played a crucial role in mediating TRAIL cytotoxicity and monocytic maturation of HL-60 cells. Moreover, experiments performed using agonistic polyclonal antibodies, which mimic the interactions between TRAIL and each TRAIL receptor, indicated that TRAIL-R1 was responsible for mediating the TRAIL-induced maturation. Importantly, the maturational effects of TRAIL were observed also in primary normal CD34+ cells, seeded in serum-free liquid cultures for 4 to 8 days in the presence of SCF + GM−CSF. After treatment with TRAIL for 3 additional days, a significant increase in CD14 and CD11b expression, coupled with an increased number of mature monocytes and macrophages, was noticed in the absence of cytotoxicity. These data disclose a novel role for TRAIL as a positive regulator of myeloid differentiation. Moreover, the dichotomous effect of TRAIL on malignant cells (early induction of apoptosis and monocytic maturation of the surviving cells) might have important therapeutic implications for the treatment of acute myeloid leukemia.
Creating space: an antigen-independent, CpG-induced peripheral expansion of naive and memory T lymphocytes in a full T-cell compartment
Authors: Davila Eduardo , Velez Maria G. , Heppelmann Carrie J. , Celis Esteban
Published: September 2002

Many of the mechanisms that govern T-cell homeostasis remain obscure. Here we report that repeated administration of synthetic oligodeoxynucleotides containing unmethylated cytosine-guanine motifs (CpG-ODN) into mice induces a systemic antigen-independent expansion of naive and memory T cells in a full T-cell compartment. Expansion of T cells was observed on both CD4+ and CD8+ T-cell subsets and was produced not by inducing the proliferation of the cells but by preventing their death. The antiapoptotic effects of CpG-ODN on T cells were observed against activation-induced death and growth factor withdrawal–mediated death. The ability of CpG-ODN to protect T cells from these forms of death was associated with the up-regulation of antiapoptotic gene products including c-FLIP, bcl-xL, and, to some extent, bcl-2. The effect of CpG-ODN on naive and memory T cells required the expression of CD28 and was not dependent on the presence of B lymphocytes, suggesting that other antigen-presenting cells that respond to CpG-ODN, such as dendritic cells, may provide antiapoptotic signals to T cells in an antigen-independent but CD28/B7-dependent fashion. The present findings suggest that CpG-ODN can disrupt normal T-cell homeostasis not by acting as a mitogen but by preventing T-cell death that normally takes place as a mechanism to maintain steady-state levels of T cells. These findings support a potential means to expeditiously replenish and maintain the peripheral lymphocyte population after severe immunodepletion such as that which occurs in HIV-infected individuals and individuals undergoing cytoablative therapies.
The antiapoptosis protein survivin is associated with cell cycle entry of normal cord blood CD34+ cells and modulates cell cycle and proliferation of mouse hematopoietic progenitor cells
Authors: Fukuda Seiji , Foster Richard G. , Porter Scott B. , Pelus Louis M.
Published: September 2002

The inhibitor of the apoptosis protein (IAP) survivin is expressed in proliferating cells such as fetal tissues and cancers. We previously reported that survivin is expressed and growth factor regulated in normal adult CD34+ cells. Herein, we examined survivin expression in CD34+ cells before and after cell cycle entry and demonstrate a role for survivin in cell cycle regulation and proliferation. Analysis of known human IAPs revealed that only survivin is cytokine regulated in CD34+ cells. Survivin expression is coincident with cell cycle progression. Up-regulation of survivin by thrombopoietin (Tpo), Flt3 ligand (FL), and stem cell factor (SCF) occurred in underphosphorylated-retinoblastoma protein (Rb)positive, Ki-67negative, and cyclin DnegativeCD34+ cells. Quantitative real-time reverse transcription–polymerase chain reaction (RT-PCR) and multivariate flow cytometry demonstrated that Tpo, SCF, and FL increase survivin mRNA and protein in quiescent G0 CD34+cells without increasing Ki-67 expression, indicating that cytokine-stimulated up-regulation of survivin in CD34+cells occurs during G0, before cells enter G1. Selective inhibition of the PI3-kinase/AKT and mitogen-activated protein kinase (MAPKp42/44) pathways blocked survivin up-regulation by growth factors before arresting cell cycle. Retrovirus transduction of survivin-internal ribosome entry site–enhanced green fluorescent protein (survivin-IRES-EGFP) in primary mouse marrow cells increased granulocyte macrophage–colony-forming units (CFU-GM) by 1.7- to 6.2-fold and the proportion of CFU-GM in S phase, compared to vector control. An antisense survivin construct decreased total and S-phase CFU-GM. These studies provide further evidence that survivin up-regulation by growth factors is not a consequence of cell cycle progression and strongly suggest that survivin is an important early event for cell cycle entry by CD34+cells.
UV Absorbance By Thallus Extracts of Umbilicate Lichens
Authors: Fahselt Dianne
Published: September 2002

Eleven stands of umbilicate lichens exhibiting a range of variabilities in enzyme banding patterns were compared on the basis of the ultraviolet (UV)absorbing properties of thallus extracts. Stands of Umbilicaria veilea, which were some of the most variable enzymatically, had the lowest UV absorbancy in extracts, and stands of Lasallia papulosa, which were among the least variable enzymatically, showed more UV absorbance than others. Umbilicaria deusta, U. muhlenbergii and U. mammulata had intermediate levels of absorbance. Negative correlations (P = 005–007) were found between enzyme polymorphism and UV absorbance in the ranges 215–220, 269–271 and 304–305 nm. There was also a significant negative correlation at P = 003 between enzyme variability and thallus dry weight extractable with either ethanol or acetone.
Decomposition studies on New Zealand and antarctic lichens
Authors: Greenfield L. G.
Published: September 2002

The decomposition of ground, dead (oven-dried) lichens has been studied in laboratory experiments that aimed to simulate decomposition in nature. Enzymes, common in soil animal guts and soil microbes, solubilized 29% of the lichen weight and 25% of lichen nitrogen. Approximately 9% of lichen nitrogen was mobilized to mineral forms during 97 days' incubation in soil or sand. Low moisture levels reduced the amount of nitrogen mobilized. In short-term (30 days) incubation studies, lichens at optimum moisture but low temperature lost 9% of their initial dry weight due to microbial metabolism. In contrast, lichens incubated for 30 and 135 days at similar moisture levels but higher temperatures lost 19% and 30% respectively of their initial dry weight due to microbial metabolism.
Phaeographina Buxi, A New Genus And Species For The European Lichen Flora
Authors: Etayo J.
Published: September 2002

Phaeographina buxi is described from Buxus sempervirens to the south of the Pyrenees. It lives in canyons and geomorphologically similar habitats with a rich assemblage of epiphyllous lichens. The tropical genus Phaeographina is reported for the first time on the European continent.
The Lichen Genus Bactrospora
Authors: Egea J. M. , Torrente P.
Published: September 2002

Twenty species and one variety of the genus Bactrospora Massal. are revised. The following new species are described: B. arthonioides sp. nov., B. brodoi sp. nov., B. carneopallida sp. nov., B. incana sp. nov., B. intermedia sp. nov., and B. spiralis sp. nov. Six species of Lecanactis and one of Bacidia are transferred to Bactrospora. A key is given.
Biatora Meiocarpa (NYL.) Arnold, a Misunderstood Species
Authors: Ekman Stefan
Published: September 2002

Biatora meiocarpa (Nyl.) Arnold (Lecanorales, lichenized Ascomycotina) is described and compared with some of its relatives, particularly B. helvola Körber ex Hellbom (syn. Lecideahelvola), a species with which it has often been confused. Biatora meiocarpa and B. helvola differ in (1) width of the paraphysis tops, (2) hymenium height, (3) apothecium width, (4) gelatinization of the paraphyses, (5) composition of the excipulum (hyphae with ellipsoid or shortly rectangular lumina in B. meiocarpa, narrowly linear lumina in B. helvola), (6) chemistry (1-2 triterpenoids or no substances in B. meiocarpa, gyrophoric acid plus 1-2 triterpenoids in B. helvola), and (7) length and shape of conidia. The variation in the first three characters overlaps but one–way analysis of variance (ANOVA) shows that B. meiocarpa and B. helvola differ significantly in each of these characters. Three further characters were subjected to ANOVA: spore length, spore width and length/width ratio of the spores. No statistically significant differences were observed in these characters.Biatora meiocarpa generally occurs on smooth bark of broad–leaved trees and shrubs. It is known from northern Sweden, Finland, and northwestern Russia
Notes on Amandinea Petermannii Comb.nov. (Physciaceae) from Antarctica
Authors: Matzer M. , Mayrhofer H. , Scheidegger Ch.
Published: September 2002

The new combination Amandinea petermannii (Hue) Matzer, Mayrh. & Scheidegger; is proposed. The taxonomy, morphology, anatomy, chemistry, ecology and distribution of this lichen are discussed. Rinodina convoluta D. C. Lindsay is synonym of A. petermannii.
Deux Associations Lichéniques Corticoles Nouvelles, Mésoméditerranéennes, Sciaphiles: Le Ramonio-Striguletum Mediterraneae Et Le Striguletum Affinis
Authors: Bricaud Olivier , Roux et Claude
Published: September 2002

A description is given of the corticolous, sciaphilous lichen associations Ramonio-Stiguletum mediterraneae Bricaud & Roux ass. nov. and Striguletum affinis Bricaud & Roux ass. nov. These associations occur mainly in mesomediterranean Quercus ilex forests and less usually in mesomediterranean or supramediterranean Quercus pubescens forests. The former usually grow on the more or less decayed rhytidome of Quercus ilex, the latter exclusively on Hedera helix trunks.
New and Noteworthy Lichenicolous Fungi From Southernmost South America
Authors: Wedin Mats
Published: September 2002

Abrothallus secedens Wedin & R. Sant. sp. nov., commensalistic on species of Pseudocyphellaria, from Argentina and Kenya and Abrothallus granulatae Wedin sp. nov., parasitic on Pseudocyphellariagranulata, from Argentina (Tierra del Fuego) are described. Vouauxiomycesgranulatae Wedin sp. nov., is regarded as the anamorph of A. granulatae. Sphaerellothecium minutum Hafellner is recorded for the first time from Antarctica and South America, Phaeosporobolus alpinus R. Sant., Alstrup & D. Hawksw. from Antarctica and Argentina, Arthonia epiphyscia Nyl., Dacampia rufescentis (Vouaux) D. Hawksw., Polycoccum pulvinatum (Eitner) R. Sant. And Stigmidium pumilum (Lettau) Matzer & Hafellner from South America and Nesolechia oxyspora (Tul.) Massal. and Pyrenidium actinellum Nyl. from Chile.
Bacidia Caesiovirens, A New Lichen Species from Western Europe
Authors: Ekman Stefan , Holien Håkon
Published: September 2002

Bacidia caesiovirens S. Ekman & Holien sp. nov. is described from Norway, and the British Isles. It occurs on trunks of deciduous trees in coastal forests. This species is usually sterile and is characterized by its conspicuously blue-green, granular thallus, which contains a bluish, N+ purple pigment. It is closely related to B. biatorina (Körb.) Vain., but differs from this species in a number of features apart from thallus pigmentation: the thallus granules are smaller, the amount of hyphal projections from the surface of the thallus granules is larger, and the internal pigmentation of the apothecia is different. Bacidia auerswaldii (Hepp ex Stizenb.) Mig. has a similarly granular thallus but differs from B. biatorina and B. caesiovirens in having wide, fusiform spores and smaller thallus granules. Bacidia absistens (Nyl.) Arnold has an internal apothecium pigmentation similar to B. caesiovirens, but differs in having a smooth thallus, and an abundance of minute crystals in the excipulum.
Aquatic Species of Verrucaria in Eastern Australia
Authors: McCarthy P. M.
Published: September 2002

Ten species and one variety of Verrucaria Schrader are known from creeks and rivers in eastern Australia. Verrucaria austroalpina sp. nov., V. inconstans sp. nov., V. mundula sp. nov., V. mundula var. deminuta var. nov., V. phaeoderma sp. nov., V. tasmanica sp. nov. and V. tholocarpa sp. nov. are described. The combination V. puncticulata (P. M. McCarthy) P. M. McCarthy is made for V. hydrela var. puncticulata P. M. McCarthy. Verrucaria margacea (Wahlenb.)Wahlenb. and V. praetermissa (Trevisan) Anzi are reported from the Southern Hemisphere for the first time.
Aphanopsidaceae—A New Family of Lichenized Ascomycetes
Authors: Printzen C. , Rambold G.
Published: September 2002

The monotypic lichen genera Aphanopsis and Steinia have various ecological and anatomical features in common. Both genera exhibit a particular ascus type and are recognized as representing a family of their own, the Aphanopsidaceae. This family is preliminarily placed in the order Lecanorales.
Chlorophyll A Fluorescence and Chlorophyll Content in Parmelia Quercina Thalli from a Polluted Region of Northern Castellon (Spain)
Authors: Calatayud A. , Sanz M. J. , Calvo E. , Barreno E. , del Valle-Tascon S.
Published: September 2002

Measurements of modulated chlorophyll a fluorescence emission and chlorophyll content were made in thalli of Parmelia quercina collected from northern Castellon(Spain). Althoug high air pollution concentrations have been measured in this area, the ratio of variable to maximal fluorescence is unaffected. Following dark-adaptation, the response to irradiance of chlorophyll fluorescence was examined. With respect to control samples, thalli collected in northern Castellon consistently showed differences in fluorescence quenching, the efficiency of excitation energy capture and quenching of basal fluorescence. However, the quantum ield of photochemistry and non-cyclic electron flow were not affected. The changes in chlorophyll fluorescence parameters were observed in the absence of both visual injuries and decrease in chlorophyll content. The results are discussed with regard to the possible role of environmental stress in chlorophyll fluorescence yield.
Distribution and Succession of Lichens Associated with Prunus Spinosa at Dungeness, England
Authors: Ferry B. W. , Lodge E.
Published: September 2002

The distribution and succession of epiphytic and other associated lichens on blackthorn (Prunus spinosa) growing on the shingle at Dungeness is described. Some 33 epiphytic species, which exhibited a range of ecological strategies from pioneer to late colonizers, were recorded. Both the rate of change of status (age) of blackthorns and the progress of lichen colonization seemed to depend on whether the bushes were growing directly on shingle or on adjacent alluvial soil; both processes seeming to be more rapid on the former substratum. Terricolous lichens, of which 18 were recorded, generally appeared late in the succession and mostly amongst bushes growing on shingle. Rabbits often invaded the blackthorns, especially those on alluvium, and probably contributed to the lack of terrestrial lichens under these bushes. Blackthorns growing on shingle tended to be more prostrate in form than those on alluvium.
New Foliicolous Species of Strigula from Lord Howe Island, Australia
Authors: McCarthy P. M. , Streimann H. , Elix J. A.
Published: September 2002

Strigula fossulicola sp. nov. and S. oceanica sp. nov. are described from Lord Howe Island, New South Wales, Australia. They inhabit the leaves of endemic shrubs and trees and are distinguished by ascospores that fracture at the septum prior to maturity.
Some Aspects of the Water Relations of the Lichen Parmotrema Tinctorum Measured Using Thermocouple Psychrometry
Authors: Beckett R. P.
Published: September 2002

The thermocouple psychrometer was used to determine water potential, Ψ and its components in the lichen Parmotrema tinctorum. Data suggested that using conventional pressure-volume curves to study the water relations of lichens may give anomalous results, possibly because lichens may contain appreciable amounts of intercellular water. A way of correcting pressure-volume curves to remove the effect of intercellular water is discussed. Parmotrema tinctorum had a very low osmotic potential at full turgor (c. −2.5 MPa), and a low bulk modulus of elasticit (c. 2.1 MPa). As a result, P. tinctorum lost turgor only when the relative water content dropped below 0.47. Likely benefits of this for the lichen are discussed.
Optimal Quantum Yield of Photosystem II and Chlorophyll Degradation of Lobaria Pulmonaria in Relation to pH
Authors: Gauslaa Yngvar , Kopperud Cor , Solhaug Knut Asbjørn
Published: September 2002

The FV/FM ratio of Lobaria pulmonaria with decreasing pH in samples from a boreal forest influenced by acid rain in SE Norway, suggesting that low pH has an effect on the optimal quantum yield of PSII. The pH was measured of distilled deionized water in which lobes from different habitats were rinsed, probably indicating the ionic environment of the lichen. The best prediction of FV/FM was found in a multiple regression model including the explanatory variables: pH, a/b-ratio and chlorophyll degradation measured as the 666/666a ratio, all correlated positively with FV/FM but not with each other. The commonly used chlorophyll degradation 435/415 ratio cannot be used for L. pulmonaria because of an unidentified, habitat-influenced brownish pigment with high absorbance in the 415–435 nm wavelength range.
Two New Freshwater Species of Verrucariaceae From Yunnan, China
Authors: Harada H. , Wang L.-S.
Published: September 2002

Two species of Verrucariaceae, Endocarpon globosum Harada & L.-S. Wangsp. nov., and Staurothele yunnana Harada & L.-S. Wang sp. nov., are described. Both grow on stones submerged in a stream on Meili Snow Mountain in NW Yunnan, China.
Spirographa Vinosa, a New Odontotremoid Fungus on Ochrolechia and Pertusaria
Authors: Holien Håkon , Triebel Dagmar
Published: September 2002

Spirographa vinosa Holien & Triebel is described from boreal spruce forest of Norway. It is lichenicolous on different species of Ochrolechia and Pertusaria. Within the genus S. vinosa is characterized by its 8-spored asci, up to 5-septate ascospores with obtuse ends and its apothecial pigments causing aeruginose and purplish reactions with KOH.
Hyalpyrenia Japonica, a Peculiar New Pyrenocarpous Lichen Genus from Japan
Authors: Harada H.
Published: September 2002

Hyalopyrenia japonica Harada (lichenized Ascomycotina) is described as new genus on the basis of a specimen from friable rock in forests in Chiba-ken, central Japan. It is characterized by a poorly developed crustose thallus, a Trentepohlia phycobiont, immersed perithecia with hyaline walls, simple paraphyses and periphyses, non-amyloid bitunicate asci with an ocular chamber, and transversely septate hyaline spores. Hyalopyrenia is monotypic, and its taxonomic position is uncertain.
Vagnia, a Remarkable Coelomycete Producing a Black Columnar Cirrus on Peltigera in Poland
Authors: Hawksworth David L. , Miadlikowska Jolanta
Published: September 2002

The new genus Vagnia is introduced for the single species V. cirriformia discovered on thalli of Peltigera in Poland; it appears to be a pathogen as the cortex is destroyed in a rounded patch within which the conidiomata occur. The fungus is characterized by cupulate to doliiform conidiomata clothed in white hairs and from which a black columnar cirrus of conidia arises. The simple ellipsoid conidia are hyaline when viewed individually and are formed enteroblastically from elongate conidiogenous cells supported by branched conidiophores.
Amplification of Fungal rDNA-Its Regions from Non-Fertile Specimens of the Lichen-Forming Genus Parmelia
Authors: Crespo Ana , Bridge Paul D. , Hawksworth David L.
Published: September 2002

A method is described for the selective amplification of single mycobiont rDNA sequences from vegetative, non-ascomatal material of the lichenized thalli of Parmelia sulcata and P. saxatilis. The method includes a simple DNA extraction procedure employing rhizines, which avoids the use of liquid nitrogen disruption methods and phenol based extractions. The resulting amplified DNA is suitable for restriction enzyme analysis, and can be used to provide material for investigating population distribution and species concepts.
Notes on Xanthoria Th. Fr. II. Xanthoria Poeltii, a New Lichen Species from Europe
Authors: Kondratyuk Sergey , Kärnefelt Ingvar
Published: September 2002

Xanthoria poeltii, a new species combining characters of X. candelaria and X. ulophyllodes from Sweden, Denmark, Germany and Hungary, is described and illustrated. Comments about its differences from related taxa are provided.
The Lichen Vegetation of Acid Watercourses in England
Authors: Gilbert O. L. , Giavarini V. J.
Published: September 2002

The lichen vegetation of forty-five acid watercourses in England is described and related to ecological variables. The zonation scheme adopted for chalk and limestone streams that involves four overlapping bands of lichen vegetation related to length of submergence is also appropriate for this habitat. The flora involves around 90 species, a number of which are rarely recorded specialists. Evidence is presented that substratum chemistry is a more powerful ecological factor than water chemistry. An attempt has been made to relate the lichen flora to homogeneous stream segments from the headwaters down to the alluvial lowlands. An investigation into the effects of water quality showed that both suspended solids (silting) and eutrophication are highly deleterious to the lichen flora; the submerged and fluvial mesic zones are the first to be affected. The zonation across streams in England is compared with those reported from Germany and found to be closely similar.
Vegetative Establishment and Expansion By the Mycobiont of Cladina Subtenuis
Authors: Hammer Samuel
Published: September 2002

Cladina subtenuis establishes and expands by mechanisms of the thallus mycobiont. Vegetative reproduction occurs through thallus fragmentation, branch ‘ de-differentiation ’, and the extension of the underground prothallus. Establishment hyphae can be considered as any hyphae that provide the mechanism for these modes of clonal thallus extension. They may originate in various parts of the thallus, laterally on branch surfaces, at the growing tips of branches, or from the inner fungal layers of the podetium. The thallus of C. subtenuis is structurally and functionally plastic. Parts of the photosynthetic lichen thallus can transform into nonphotosynthetic fungal aggregations, and non-photosynthetic aggregations may re-establish as a photosynthetic lichen thallus. These activities expand the area occupied by the clone, and potentially increase its photosynthetic surface.
New and interesting Saxicolous species of strigula
Authors: McCarthy P.M.
Published: September 2002

The saxicolous Strigula fractans sp. nov. and S. rupestris sp. now are described from Lord Howe Island, New South Wales, Australia. A new combination, S. decipiens (Malme) P. M. McCarthy, is proposed for Porina decipiens Malme, and a key to the 17 saxicolous species of Strigula is provided.
Dermatocarpon Leptophyllodes and Related Species in the British Isles
Authors: Orange Alan
Published: September 2002

The species of Dermatocarpon occurring in the British Isles are reviewed, with special reference to the hydrophilous species; a number of related species not yet recorded for the British Isles are also briefly treated. Dermatocarpon deminuens and D. leptophyllodes are confirmed as British; the name D. leptophyllum should be deleted from the British list. The name D. melophyllum is shown to be based on discordant elements. A key is provided to the British and Irish species.
Two New Biatora Species from Western Norway and Madeira
Authors: Printzen Christian , Holien Håkon , Etayo Javier
Published: September 2002

Biatora hertelii Printzen & Etayo and B. troendelagica Holien & Printzen are described as new to science. Diagnostic characters, systematic affinities, ecology and distribution of both species are briefly discussed. Divaricatic acid is reported for the first time from a species of Biatora
The Lichen Symbiosis—What is so Spectacular about it?
Authors: Honegger Rosmarie
Published: September 2002

Lichen mycobionts are typical representatives of their fungal classes but differ from non-lichenized taxa by their manifold adaptations to symbiosis with a population of minute photobiont cells. Most interesting are the morphologically complex macrolichens, the fungal partner of which competes for space above ground and contains photobiont cells optimally positioned for gas exchange and illumination. Such thalli are the product of an amazing hyphal polymorphism, with multiple switches between polar and apolar growth and hydrophilic or hydrophobic cell wall surfaces. Hydrophobic sealing of the apoplastic continuum between the partners by means of mycobiont-derived hydrophobic compounds canalizes the fluxes of solutes during the often quite dramatic de- and rehydration processes and keeps the algal layer gas-filled at any level of hydration. The impressive tolerance of drought, heat and cold stress of most lichen-forming fungi and their photobionts is due to a very interesting combination of protective and repair mechanisms at the cellular level, the molecular bases of which remain to be explored. Contemporary experimental lichenology is analysed and strategies are proposed aimed at better integration into mainstream biology.
Pesticide Usage and Epiphytic Lichen Diversity in Romanian Orchards
Authors: Bartók Katalin
Published: September 2002

The epiphytic lichen floras of different orchards (intensive, semi-intensive apple cultivation and traditional old private garden) in North-West Romania were compared with and without pesticide treatment. Species richness was negatively influenced by the frequency of pesticide treatment.
Oxidative Stress and Ascorbic Acid Contents in Parmotrema Reticulatum and Parmelia Sulcata Thalli
Authors: Caviglia A. M. , Modenesi P.
Published: September 2002

Paraquat-treatment of Parmotrema reticulatum and high light levels in the habitat of Pamtelia sulcata can cause oxidative stress, which promotes an increase in ascorbic acid contents of thalli. Ascorbic acid was measured by an HPLC method. In P. reticulatum the increase was more pronounced in summer than in other seasons. In P. sulcata, thalli growing in sun-exposed habitats showed a higher ascorbic acid content than shade-growingspecimens.
A New Belonia From New Zealand and a Second Record of B. Mediterranea
Authors: Coppins Brain J. , Malcolm William M.
Published: September 2002

Belonia pellucida sp. nov. is described from coastal scrubland in North Island, New Zealand. This is the third report of the genus Belonia(Gyalectales) from the Southern Hemisphere. Belonia mediterranea is reported for the second time, from Mallorca.
The Potential of Epiphytic Twig Communities on Quercus Petraea in a Welsh Woodland Site (Tycanol) For Evaluating Environmental Changes
Authors: Wolseley P. A. , Pryor K. V.
Published: September 2002

A survey of epiphytic species on annual increments of Quercus petraea twigs in a west Wales woodland has shown that distribution of lichen species and rates of succession are affected by a range of environmental conditions. Lichen communities were recorded for 1–15 years on randomly sampled twigs along marked woodland boundaries affected by a range of climatic and management conditions. Results show that there is a correlation between environmental condition and lichen communities of twigs, and that indicator species can be used to detect trends towards acidification or eutrophication.
Physiological Effect of Lichen Secondary Metabolites on the Lichen Parasite Marchandiomyces Corallinus
Authors: Torzilli A. P. , Mikelson P. A. , Lawrey J. D.
Published: September 2002

It has been suggested that the host specificity exhibited by some lichenicolous fungi depends on their ability to tolerate the secondary chemistry of potential host lichens. For example, the lichen parasite Marchandiomyces corallinus is able to degrade the tissues of the lichen Flavoparmelia baltimorensis irrespective of the presence or absence of endogenous phenolic compounds. In contrast, the degradation of tissues from the lichen Lasallia papulosa is suppressed when endogenous phenolics are not removed. We have investigated the physiological basis of this inhibition in order to understand more about how lichen chemistry infiuences host preference in lichenicolous fungi. Results showed that the secondary compounds from L. papulosa inhibit the overall growth of M. corallimis, but not the catalytic activity of its tissue-degrading polysaccharidases. This effect is different from that shown by another lichen parasite, Nectria parmeliae, where lichen compounds specifically inhibited polysaccharidase activity. Compared with the compounds of L. papulosa, the endogenous phenolics of F. baltimorensis inhibited the growth of M. corallimis substantially less and exhibited little or no inhibition of polysaccharidases. For M. corallimis, host preference appears to be associated with physiological adaptation to the chemistry of F. baltimorensis.
The Distribution, Ecology and Conservational Status of the Lichen Genus Biatora in Central Europe
Authors: Printzen Christian , Palice Zdeněk
Published: September 2002

The genus Biatora is still undercollected in many parts of its distributional range. On the basis of recent collections made by the authors and additional herbarium material not studied previously, more detailed statements on the ecology, distribution and conservational status of Biatora species in Central Europe are possible. Distribution maps are provided for B. fallax, B. mendax, B. ocelliformis, B. rufidula, B. sphaeroidiza, and B. vernalis. Biatora species are almost exclusively non-saxicolous and, in general, prefer humid habitats. Many species are chionophilous and extremely shade-tolerant. Three main distributional patterns can be observed: (sub-)arctic-alpine species, sub-oceanic-montane species, and species of montane coniferous or mixed coniferous forests. Biatora efflorescens, B. flavopunctata and B. subduplex are relatively frequent species and are not threatened. Biatora rufidula and B. vacciniicola must be regarded as extinct in Central Europe. The following species are reported for the first time from the respective countries: B. chrysantha from Romania, B. efflorescens from Romania and Ukraine, B. fallax from Austria and Ukraine, B. mendax from the Czech Republic, B. ocelliformis from Romania, and B. sphaeroidiza from Germany, Austria, the Czech Republic and Romania.
Additions and Corrections to the Foliicolous Lichen Flora of Costa Rica. The Family Gyalectaceae
Authors: Lücking Robert
Published: September 2002

This paper provides a revision of the foliicolous representatives of the Gyalectaceae in Costa Rica. Five species of Coenogonium and 13 of Dimerella are distinguished. Coenogonium interplexum, C. interpositum, C. leprieurii, C. linkii and Dimerella vezdana are ubiquitous as to the choice of their substratum, whereas C. moniliforme and Dimerella lutea are facultatively foliicolous. The remainder are typically foliicolous taxa but may occasionally be found on bark. The following species are for the first time reported as foliicolous from Costa Rica: Coenogonium interplexum, C. interpositum, C. leprieurii, C. moniliforme, Dimerella fallaciosa, D lisowskii, and D. aff. pilifera. Three new species are described: Dimerella isidiifera sp. nov. with disciform isidia, D. subzonatasp. nov. with small, bright yellow, dentate apothecia and a whitish prothallus, and D. siquirrensis sp. nov. with large, orange apothecia and a thin whitish prothallus. A key is presented for neotropical foliicolous Gyalectaceae, and notes on the distribution and ecology of the species are given.
Observations on the Genus Psammina, Including the Description of Two New Algicolous and Lichenicolous Species
Authors: Earland-Bennett P. M. , Hawksworth D. L.
Published: September 2002

Psammina inflate Earland-Bennett & D. Hawksw. and P. simplex Earland-Bennett & D. Hawksw. are described as new species from coccoid green algae and crustose or leprose lichens in lowland Britain. Additional records and hosts for P. stipitata are reported, and a key to the four species now known in the British Isles is presented. Psammina simplex is the more strongly pathogenic of the species, eventually destroying its hosts. The discovery of these new sp cies adds weight to the view that the genus is more appropriately regarded as a hyphomycete rather than an acervular coelomycete. The size, shape and septation dimensions of the conidial arms were found to be the most reliable characters for specie separations in the genus. Pycnopsammina lobariae Diederich & Etayo is also cited from the British Isles for the first time.
Pcr Optimization and Troubleshooting, with Special Reference to the Amplification of Ribosomal DNA in Lichenized Fungi
Authors: Ekman Stefan
Published: September 2002

Factors affecting the outcome of a PCR is discussed. Nested PCR is described and a protocol that has been shown to work well for the amplification of ribosomal genes in ascomycetes is described. It is claimed that DNA extracts of lichenized fungi, contrary to many other organism groups, are often contaminated by other fungi. This poses a problem due to the preferential amplification of short intron-lacking sequences over longer, intron-containing ones, particularly when extension time is limited. A simple protocol for optimizing and troubleshooting PCRs is presented.
Antimicrobial, Antiviral and Cytotoxic Activity of New Zealand Lichens
Authors: Perry Nigel B. , Benn Michael H. , Brennan Nerida J. , Burgess Elaine J. , Ellis Gill , Galloway David J. , Lorimer Stephen D. , Tangney Raymond S.
Published: September 2002

A total of 69 species of lichens have been collected from various locations around New Zealand. Screening of extracts of these species for antimicrobial, antiviral and cytotoxic activity showed a high proportion with biological activity. Active extracts were generally from species known to contain phenolic compounds. Bioactivity-directed isolation work on Cladia retipora, Pseudocyphellaria glabra and P. homoeophylla led to the identification of usnic acid as the main antimicrobial, cytotoxic and antiviral component in these three species.
Three New Species in the Lichen Genus Degelia
Authors: Jørgensen P. M , Kantvilas G. , Galloway D. J
Published: September 2002

The following new species are described: Degelia calcicola P. M. Jørg. & Kantvilas, a squamulose species from wet calcareous rocks in Tasmania; D. Crustacea P. M. Jørg. & D. J. Galloway, a crustose, corticolous species from northern New Zealand; and D. subcrustata P. M. Jørg. & Kantvilas from dry granitic rocks in southern Australia and Tasmania.
Studies on the Lichen Family Thelotremataceae in Tasmania. The Genus Chroodiscus and its Relatives
Authors: Kantvilas Gintaras , Vězda Antonín
Published: September 2002

The Tasmanian species of the family Thelotremataceae with thin-walled ascospores and exfoliating, chroodiscoid apothecia are studied in detail. Problems in the delimitation of genera are discussed, and characters such as the morphology of the apothecia, structure and form of the exciple, presence of periphyses, ascus structure, ascospore morphology and thallus chemistry are evaluated. The concept of the typically foliicolous genus Chroodiscus (Müll. Arg.) Müll. Arg. is expanded to include corticolous and terricolous species, and the new taxa C. asteliae Kantvilas & Vězda, C. australis Kantvilas & Vězda, C. australis subsp. tasmanicus Kantvilas & Vězda, C. lamelliferus Kantvilas & Vězda and C. minor Kantvilas & Vězda are described and illustrated. The related Australasian species, C. megalophthalmus (Müll. Arg.) Vězda & Kantvilas is also treated. Two new genera are also described. Pseudoramonia Kantvilas & Vězda, based on the Venezuelan species, P. stipitata (Vězda & Hertel) Kantvilas & Vězda, is introduced to accommodate P. richeae Kantvilas & Vězda; Topeliopsis Kantvilas & Vězda is described to include the Tasmanian taxa, T. muscicola Kantvilas & Vězda and T. rugosa Kantvilas & Vězda, and the North American species T. toensbergii Vězda & Kantvilas.
Calcium Oxalate and Medullary Architecture in Xanthomaculina Convoluta
Authors: Modenesi Paolo , Piana Massimo , Giordani Paolo , Tafanelli Alessandra , Bartoli Antonella
Published: September 2002

The anatomy of Xanthomaculna convolute shows adaptation to a vagrant life form and to the moisture conditions of its habitat. The differential swelling of the irregularly thickened upper cortex and the medulla, in addition to the rigid medullary structure, due to the deposition of calcium oxalate, allow orderly hygroscopic thalline movements. The architecture of the medulla appears to be closely related to masonry-like arches where the material is only stressed by compression and the stresses are distributed at the hinges. The possible role of crystalline medullary deposition as a radiation reflector is also suggested.
Measurement of Age and Growth Rate in the Crustose Saxicolous Lichen Caloplaca Trachyphylla Using 14C Accelerator Mass Spectrometry
Authors: Clark B. M. , Mangelson N. F. , Clair L. L. St. , Rees L. B. , Bench G. S. , Southon¶ J. R.
Published: September 2002

Sections of the crustose saxicolous lichen, Caloplaca trachyphylla, were dated using 14C accelerator mass spectrometry (AMS). The data show a stron linear dependence of radial position on time (r=0.993), suggesting a constant radial growth rate. This specimen had averaged a marginal growth rate of 1.48 mm/year. Extrapolation of the growth curve yields a thallus age of 20 years. These data demonstrate the feasibility of using AMS technology to precisely date lichen tissues and determine growth rates of lichen thalli.
Biomass of Arboreal Lichens and its Vertical Distribution in a Boreal Coniferous Forest in Central Finland
Authors: Liu Chunjiang , Ilvesniemi Hannu , Westman Car J.
Published: September 2002

The biomass of lichens and its vertical distribution on trees were investigated in a > 100-year-old boreal forest in central Finland. The lichen biomass on individual trees was 1292–3669 g tree−1 on Picea abies and 742 g tree −1 on Pinus sylvestris. More than half of the biomass occurred on dead branches. The proportion of Hypogymnia physodes appeared to rise with the canopy height while the other lichens (Platismatia glauca, Bryoria spp. and Pseudevernia furfuracea) decreased. Mean total lichen biomass for sampled trees on an aerial basis was 163 gm −2. The standing crop of litter lichen deposited on ground was about9 gm −2.
Lecanora Herteliana (Lecanoraceae, Ascomycetes), a New Lichen Species from Spain
Authors: Calatayud Vicent , Barreno Eva
Published: September 2002

Lecanora herteliana is described from several collections from hard siliceous sandstone, in typically Mediterranean habitats in eastern Spain. The new species has a whitish thallus containing atranorin and norstictic acid. Its apothecia are mostly black, with a thalline exciple, which is finally excluded, and with a well developed true exciple.Lecanora herteliana is most closely related to L. subcoarctata, and it is discussed in relation to this species and other members of the L. marginata group.
Identification of Photobionts from the lichen family Physciaceae using algal-specific ITS rDNA sequencing
Authors: Helms Gert , Friedl Thomas , Rambold Gerhard , Mayrhofer Helmut
Published: September 2002

The identity of photobionts from 20 species of the Physciaceae from different habitats and geographical regions has been determined by ITS rDNA sequence comparisons in order to estimate the diversity of photobionts within that lichen group, to detect patterns of specificity of mycobionts towards their photobionts and as a part of an ongoing study to investigate possible parallel cladogenesis of both symbionts. Algal-specific PCR primers have been used to determine the ITS rDNA sequences from DNA extractions of dried lichens that were up to 5 years old. Direct comparisons and phylogenetic analyses allowed the assignment of Physciaceae photobionts to four distinct clades in the photobiont ITS rDNA phylogeny. The results indicate a diversity within the genus Trebouxia Puymaly and Physciaceae photobionts that is higher than expected on the basis morphology alone. Physciaceae photobionts belonged to 12 different ITS lineages of which nine could unambiguously be assigned to six morphospecies of Trebouxia. The identity of the remaining three sequences was not clarified; they may represent new species. Specificity at the generic level was low as a whole range of photobiont species were found within a genus of Physciaceae and different ranges were detected. The photobionts of Physcia (Schreb.) Michaux were closely related and represented one morphospecies of Trebouxia, whereas the algal partners of Buellia De Not and Rinodina (Ach.) Gray were in distant lineages of the ITS phylogeny and from several Trebouxia morphospecies. Photobiont variation within a genus of Physciaceae may be due to phylogeny, geographical distance or because photobionts from neighbouring lichens were taken (“algal sharing“). At the species level Physciaceae mycobionts seem to be rather selective and contained photobionts that were very closely related within one morphospecies of Trebouxia.