bluuebunny/crossref_metadata_2025_split huggingface dataset:
Heterozygosity in MAT locus affects stability and function of microtubules in yeast
Authors: Steinberg‐Neifach Olga , Eshel Dan 
Published: September 2002

AbstractThe dynamic nature of microtubules is important for their cellular function and is tightly regulated by the cell cycle machinery and through other pathways that act on microtubule‐associated proteins. Recently, it was reported that simultaneous expression of MATa and MATα genes in haploid cells of Saccharomyces cerevisiae increases microtubule stability 〚Mol. Gen. Genet. 264 (2000) 300〛. In order to investigate the effect of zygosity in the MAT loci on microtubules independent of the effect of the actual ploidy, we compared microtubule stability and function in homozygous (MATa/MATa) and heterozygous (MATa/MATα) wild‐type diploid cells. It was found that homozygosity in the MAT locus decreases stability of both cytoplasmic and nuclear microtubules. This was expressed in a more symmetrical distribution in the placement of the spindle relative to the neck, a delay in cytokinesis and reduced fidelity of chromosome segregation in these cells compared to the heterozygotes. Our results suggest that expression of both MAT loci initiates a pathway that results in an increase in microtubule stability and the fidelity of chromosome segregation in diploids. This pathway is independent of the pathway that determines the budding pattern in haploids and diploids, which is also initiated by simultaneous expression of MATa and MATα genes.
Study of Antigen-Processing Steps Reveals Preferences Explaining Differential Biological Outcomes of Two HLA-A2-Restricted Immunodominant Epitopes from Human Immunodeficiency Virus Type 1
Authors: Cohen W. M. , Bianco A. , Connan F. , Camoin L. , Dalod M. , Lauvau G. , Ferriès E. , Culmann-Penciolelli B. , van Endert P. M. , Briand J. P. , Choppin J. , Guillet J. G. 
Published: September 2002

ABSTRACTCytotoxic T-lymphocyte (CTL) responses directed to different human immunodeficiency virus (HIV) epitopes vary in their protective efficacy. In particular, HIV-infected cells are much more sensitive to lysis by anti-Gag/p17(77-85)/HLA-A2 than to that by anti-polymerase/RT(476-484)/HLA-A2 CTL, because of a higher density of p17(77-85) complexes. This report describes multiple processing steps favoring the generation of p17(77-85) complexes: (i) the exact COOH-terminal cleavage of epitopes by cellular proteases occurred faster and more frequently for p17(77-85) than for RT(476-484), and (ii) the binding efficiency of the transporter associated with antigen processing was greater for p17(77-85) precursors than for the RT(476-484) epitope. Surprisingly, these peptides, which differed markedly in their antigenicity, displayed qualitatively and quantitatively similar immunogenicity, suggesting differences in the mechanisms governing these phenomena. Here, we discuss the mechanisms responsible for such differences.
RHEOLOGICAL AND MAGNETORHEOLOGICAL BEHAVIOUR OF SOME MAGNETIC FLUIDS ON POLAR AND NONPOLAR CARRIER LIQUIDS
Authors: BĂLĂU OANA , BICA DOINA , KONERACKA MARTINA , KOPČANSKY PETER , SUSAN-RESIGA DANIELA , VÉKÁS LADISLAU 
Published: September 2002

Rheological and magnetorheological behaviour of monolayer and double layer sterically stabilized magnetic fluids, with transformer oil (UTR), diloctilsebacate (DOS), heptanol (Hept), pentanol (Pent) and water (W) as carrier liquids, were investigated. The data for volumic concentration dependence of dynamic viscosity of high colloidal stability UTR, DOS, Hept and Pent samples are particularly well fitted by the formulas given by Vand (1948) and Chow (1994). The Chow type dependence proved its universal character as the viscosity data for dilution series of various magnetic fluids are well fitted by the same curve, regardless the nonpolar or polar charcater of the sample. The magnetorheological effect measured for low and medium concentration water based magnetic fluids is much higher, due to agglomerate formation process, than the corresponding values obtained for the well stabilized UTR, DOS, Hept and Pent samples, even at very high volumic fraction of magnetic nanoparticles.
Nimisia Fuegiae (Parmeliaceae), a New Lichen Genus and Species From Argentina
Authors: Kärnefelt I. , Thell A. 
Published: September 2002

AbstractNimisia fuegiae Kärnef. & Thell gen. et sp. nov. is described from Argentinian Tierra del Fuego. The new lichen differs from possibly related groups within the Parmeliaceae in unique anatomical characters, i.e. a medullary layer composed of extremely thick and strongly gelatinized periclinally arranged hyphae and a lower cortex composed of only a few layers of strongly pigmented, rather large cells. Ascus characters support its position in the Parmeliaceae. The new genus, which is named in the honour of its first discoverer, is discussed in relation to several other well-investigated members of the family.
Laurera Robusta (Trypetheliaceae), a new alpine lichen from Tasmania
Authors: McCarthy P.M. , Kantvilas G. 
Published: September 2002

AbstractLaurera robusta McCarthy & Kantvilas sp. nov. (Trypetheliaceae) is described from alpine heathland in Tasmania. Anthracothecium monosporum Müll. Arg. is synonymous with L. elatior (Stirton) D. Galloway, while L. megasperma var. tasmanica (Jatta) Zahlbr. is referable to Pyrenula.
Differential herbivore damage to calcicolous lichens by snails
Authors: Fröberg Lars , Baur Anette , Baur Bruno 
Published: September 2002

AbstractA laboratory experiment was conducted to determine the damage caused by snail grazing to 35 calcicolous lichen species and cyanobacteria from the Baltic island of Oland, Sweden. Individuals of four species of land snails (Balea perversa, Chondrina cliema, Clausilia bidentata and Helicigona lapicida) were allowed to graze on identified lichen species growing on pieces of limestone. Snail grazing on thalli and ascocarps was classified into four categories ranging from no damage to completely eaten. In general, some lichen species were heavily grazed, whereas others were only slightly damaged or not injured. Aspiciha calcarea, Tephromela atra and Verrucaria nigrescens were preferred by all snail species except Chondrina cliema. In general, lichen thalli that were not immersed in the calcareous rock and cyanobacteria were preferred, whereas ascocarps were avoided by one of the snail species (C. clienta). Immersed perithecia with a carbonized outer layer were avoided by all snail species except C. bidentata. Possibilities of chemical and mechanical defence properties in calcicolous lichens are discussed.
High performance thin layer chromatography (HPTLC), an improved technique for screening lichen substances
Authors: Arup Ulf , Ekman Stefan , Lindblom Louise , Mattsson Jan-Eric 
Published: September 2002

AbstractHigh performance thin layer chromatography (HPTLC) is a method that can be used for screening lichen substances. It is as simple to use as standard TLC, but has many advantages: It is more sensitive, it is possible to run more samples in a shorter period of time, and the amount of solvent used is much smaller. The material needed and the methods used are described in detail. Horizontal chromatogram development was used. Since two of the solvents used in system B have been substituted, and since the properties of the HPTLC plates are slightly different, our results are not entirely in accordance with the standardized TLC method. A revised table for the identification of 69 lichen substances (obtained from 62 taxa) is accordingly presented.
The Lichens of High Ground in the English Lake District
Authors: Gilbert O. L. , Giavarini V. J. 
Published: September 2002

AbstractA general account of the lichens of high-level acid habitats in the Lake District is provided. This is followed by detailed studies of base-rich sites in the Helvellyn range, acid outcrops in Langdale, and three upland tarns, one of which is of outstanding importance. The lichen vegetation is richer than in Snowdonia or the Northern Pennines, but its diversity is considerably less than that of certain individual mountains in the Scottish Highlands. The montane element is interpreted as representing the last remnants of communities that have declined gradually through the Postglacial Period. Many species are extremely rare. Current restraints on the alpine lichen flora include the climate, the predominance of wet, acid rock and heavy sheep grazing. Rhizocarpon simillimum is reported as new to the British lichen flora
Further Evidence that Activation of Net Photosynthesis by dry Cyanobacterial Lichens Requires Liquid Water
Authors: Lange O. L. , BÜdel B. , Meyer A. , Kilian E. 
Published: September 2002

AbstractIn contrast to green algal lichens, cyanobacterial species of different families, growth forms and habitats proved to be unable to attain positive net CO2 assimilation when the dry thalli were treated with air of high relative humidity; they needed liquid water for the reactivation of their photosynthetic apparatus. Identical behaviour is shown by all of the 47 lichen species with cyanobacterial photobionts, from six different genera, studied so far. This suggests a widely distributed, if not general, characteristic of cyanobacterial lichens. The difference in performance between both groups of photobionts was maintained when the lichen thallus was macerated. Furthermore, cultures of Chroococcidiopsis were unable to make use of water vapour hydration for positive net photosynthesis, and were similar in this respect to some free-living aerophilic cyanobacteria tested earlier. Possible physiological implications as well as ecological consequences for water-relation-dependent habitat selection of green-algal and cyanobacterial lichens are discussed.
A New Species of Peltula from the Sonoran Desert, Mexico
Authors: Büdel Burkhard , Nash Thomas H. 
Published: September 2002

AbstractThe new species Peltula sonorensis is described from the Sonoran Desert. It is found in several localities throughout the Mexican part of the Sonoran Desert and belongs to a distinct group within the genus Peltula, which is characterized by fairly large (up to 15 mm diam.), umbilicate-peltate squamules, growing individually and having ellipsoid to bacilliform spores.
The Effect of Agrochemicals on the Growth of Cladonia Furcata
Authors: Vagts I. , Kinder M. , Müller J. 
Published: September 2002

AbstractField experiments were conducted to test the effect of some agrochemicals on the growth of Cladonia furcata. Mineral fertilizer had no direct effect on lichen growth. In contrast, organic manure promoted the length of podetia. A lethal effect was recorded in the case of calcium cyanamide. In addition to direct effects of agrochemicals, indirect effects were also recorded.
A Method for Studying the Cellular Location of Lead in Lichens
Authors: Branquinho C. , Brown D. H. 
Published: September 2002

AbstractA number of possible displacing agents have been tested for their ability to release extracellular bound lead from Cladonia portentosa. Metal cations (Ni and Cu), thiol–rich reagents (glutathione, ammonium pyrrolidinedithiocarbamate) and some chelating agents (EGTA, EDTA at pH 9·5 or pH 2·7) were ineffective or caused membrane damage. Disodium EDTA at pH 4·5 was found to be an effective displacing agent, although the Na caused some release of intracellular K without membrane damage. This displacement procedure showed that no Pb suppliedin the laboratory entered the protoplast in 2 h. The effect of Ca, Cu, Pb, and Sr on membrane integrity was investigated.
Critical Notes on Antarctic Yellow Acarosporaceae
Authors: Castello M. , Nimis P. L. 
Published: September 2002

AbstractAll species of Antarctic Acarosporaceae (s. lat., including Biatorellaceae) with yellow thalli are revised. Four genera, Acarospora, Biatorella, Biatorellopsis, Eklundia, and ten species, all of them endemic, were previously reported from Antarctica. Our results indicate that in Antarctica Acarospora subgen. Xanthothallia s. str. includes only two species, A. gwynnii Dodge and A. flavocordia sp. nov.; Biatorella does not occur in Antarctica, the species described by Dodge belonging instead in Candelariella; the genus Eklundia is a synonym of Candelariella; Biatorellopsis does not occur in Continental Antarctica, and the genus is a synonym of Pleopsidium; Pleopsidium is represented in Antarctica by one species, P. chlorophanum, which was treated under very different generic and specific names by earlier authors. Altogether, the number of species of yellow Acarosporaceae known from Antarctica is reduced from ten to three, distributed in two genera: Acarospora and Pleopsidium. The two Acarospora species, A. gwynnii and A. flavocordiaare apparently endemic to Antarctica, whereas P. chlorophanum is a widespread bipolar lichen. A comprehensive list of synonyms and a key are provided.
Metal Content and Community Structure of Cryptogam Bioindicators in relation to Vehicular Traffic in Montseny Biosphere Reserve (Catalonia, Spain)
Authors: Glenn M. G. , Gomez-Bolea A. , Lobello R. 
Published: September 2002

AbstractThe health, abundance, metal content and species richness of corticolous macrolichens and bryophytes of Quercus ilex were compared at nine roadside stations in Montseny Biosphere Reserve, 40 km NNE of Barcelona, and at a control site outside the industrial metropolis. Stations were characterized by traffic levels and the correlated parameter airborne particles. Corticolous flora at all stations was dominated by sorediate Parmelia species (P. caperata, P. soredians, P. subrudecta, P. subaurifera, P. sulcata and P. perlata). Damage, mainly due to arthropod feeding and fungal parasites, ranged from 14 to 33% of mean cover per station in the park and was 10% at the control site. Elevated levels of Pb, Zn and Cu were found in large thalli near the roadsides.
Early Development of Transplanted Isidioid Soredia of Lobaria Pulmonaria in an Endangered Population
Authors: Scheidegger C. 
Published: September 2002

AbstractVegetative diaspores of Lobaria pulmonaria were transplanted to previously uncolonized trees. The early development of the corticated but otherwise non-stratified isidioid soredia was studied mainly by low-temperature scanning electron microscopy. Anchoring hyphae developed from cortical hyphae after 2–4 months and later apical or lateral pseudomeristematic growth zones were formed. After 15 months the growth zones further differentiated into 0·5-mm-broad lobes and revealed a stratified thallus typical for this foliose epiphytic lichen species. The experiment showed that the small population size of L. pulmonaria was limited by the low reproductive potential of the species and that it might fail to compensate for a relatively high disturbance, natural or anthropogenic, in the stand.
Lecania Pusilla, A New Bryophilous Lichen from the Trieste Karst
Authors: Tretiach Mauro 
Published: September 2002

AbstractLecania pusilla Tretiach sp. nov. is described from the Trieste Karst, where it was collected twice on epilithic mosses in protected overhangs. The new species is characterized by simple or uniseptate spores, pruinose apothecia, and Bacidia-type asci; it has a reduced, granular thallus with no lichen substances.
A New Byssoid Lichen Genus From Tasmania
Authors: Kantvilas Gintaras 
Published: September 2002

AbstractThe genus Jarmania, based on the single species J. tristis, is described. The new genus is characterized by a byssoid-leprose thallus, immarginate apothecia, asci of the Bacidia-type, strongly anastomosing paraphyses and septate, acicular ascospores. The new species is corticolous and is known only from cool temperate rainforest in Tasmania.
The Importance of Sorediate Crustose Lichens in the Epiphytic Lichen Flora of the Swiss Plateau and the Pre-Alps
Authors: Dietrich Michael , Scheidegger Christoph 
Published: September 2002

AbstractStandardized lichen surveys were conducted on 849 trees in 132 ecological long-term observation plots in the Swiss Plateau and Pre-Alps: 262 lichen taxa were identified, 64 (24%) of them sorediate crustose species. Their mean percentage of the flora on individual trees and in individual plots was even higher. The mean percentage of crustose lichen species with vegetative propagules, such as soredia, was per plot significantly higher in the Pre-Alps than in the Plateau, higher in forest than in non-forest areas, and, according to the vegetation belts, lowest in the colline-submontane zone. It was found that the biodiversity of lichens could not be determined without considering the sorediate crustose lichens. Furthermore, by performing standardized surveys of all taxa, the occurrence of the following species in Switzerland was confirmed for the first time: Cliostomum leprosum, Fuscidea arboricola, Fuscidea pusilla, Hypocenomyce leucococca, Hypocenomyce sorophora, Lecanora norvegica, Lepraria eburnea, Lepraria elobata, Lepraria jackii, Lepraria obtusatica, Lepraria rigidula, Pertusaria boreahs and Rinodina griseosoralifera. Seven taxa that displayed distinctive chemistry, could not yet be identified.
Influence of Site and Stand Factors on the Distribution of Crustose Lichens Of The Caliciales in a Suboceanic Spruce Forest Area in Central Norway
Authors: Holien Håkon 
Published: September 2002

AbstractThe distribution of crustose Caliciales has been surveyed in 100 spruce forest patches in Sør-Trøndelag, central Norway. Relationships between occurrence of the species and a number of site and stand variables were analysed by detrended correspondence analysis (DCA) and direct gradient analysis. Species diversity7 was significantly higher in old forests and in forests at higher altitudes compared to young forests and forests at lower altitudes. Old trees and snags are considered to be the most important structural components in old forests promoting species diversity of the Caliciales. Threatened or vulnerable species, such as Chaenotheca gracilliina, Cybebe gracilenta, Sclerophora coniophaea and S. peronella were confined to forest on rich soils showing no correlation with forest stand age. Chaenotheca brachypoda and C. trichialis were found to be the most typical old forest species among the Caliciales. Humidiphilous species are considered to be less affected by forestry in a humid climate. A change in forestry practice towards methods imitating the natural dynamic processes is considered necessary to maintain species diversity of the Caliciales in boreal forests.
Myeloconis, A New Genus Of Pyrenocarpous Lichens From The Tropics
Authors: McCarthy P. M. , Elix J. A. 
Published: September 2002

AbstractMyeloconis P. M. McCarthy & Elix gen. nov. is described from the Neotropics and the eastern Paleotropics. Four new species, M. erumpens, M. fecunda, M. guyanenis and M. parva, are recognized. The genus is characterized by a medulla containing previously unknown yellow or orange pigments and perithecioid ascomata with a dark, dense, almost pseudostromatal wall, a basally anastomosing, but otherwise free, hamathecium, uniformly thin-walled asci and elongate, muriform ascospores. While its affinities are uncertain, the ascomata and their contents suggest a rather close relationship with Porina Müll. Arg. and ClathroporinaMüll. Arg. (Trichotheliaceae).
The Lichen Genus Bulbothricella, A New Segregate in the Parmeliaceae from Venezuela
Authors: Marcano Vicente , Mohali Sari , Palacios-Prü Ernesto , Morales Méndez Antonio 
Published: September 2002

AbstractThe new genus Bulbothricella (Lichenized Ascomycotina,Parmeliaceae with the single species B. amazonensis (Marcano, Galiz & Morales) Marcano, Galiz, Morales & Mohali is segregated from Bulbothrix. This conclusion is based on an investigation of morphological, anatomical and chemical characters using scanning electron microscopy and thin-layer chromatography. The new genus is characterized by a pored epicortex, 12—14 spores per ascus, obovate and acrogenous conidia, and an anatomical structure and cortical chemistry resembling that of Bulbothrix..
The Identity of Photobionts From the Lichen Pyrenula Japonica
Authors: Nakano Taketo , Ihda Taka-aki 
Published: September 2002

AbstractNine specimens of Pyrenula japonica Kurokawa were collected from various areas in Japan. Photobionts were isolated from their thalli and studied taxonomically. As a result, only one species of green alga,Trentepohlia lagenifera(Hild.) Wille was identified as the photobiont of Pyrenula japonica. This is the first record of this alga from the lichen genus Pyrenula.
Teloschistes Flavicans in Great Britain: Distribution and Ecology
Authors: Gilbert O. L. , Purvis O. W. 
Published: September 2002

AbstractOver the last century, the distribution of Teloschistes flavicans has contracted from being widespread in the southern half of England and Wales to being limited to South-West England with outlying populations in Pembrokeshire and North Wales. Twelve core sites have been identified where the species is well established: ten of these are saxicolous/terricolous habitats on windy coastal cliff tops; the other two are lines of sycamore trees near the coast. At 39 further localities, some inland, the species is in very small amounts (often on one tree) and vulnerable to extinction. It is normally a member of the Parmelietum revolutae or Ramalinetum scopularis associations. The conservation of the species is discussed.
The Lichen Vegetation of Some Previously Overlooked High-Level Habitats in North Wales
Authors: Fryday Alan M. 
Published: September 2002

AbstractThe lichen vegetation associated with calcareous rocks, areas of long snow-lie and the margins of high-level lakes in North Wales is described. It includes Porpidia ochrolemma (Vain.) Brodo & R. Sant. and Rhizocarpon anaperum (Vain.) Vain, new to the British Isles, plus a further 30 taxa recorded for the first time from Wales. The relative importance of the montane lichen vegetation of North Wales is assessed by comparison with areas in other parts of the British Isles. It is shown to exceed in interest any montane area in England or Ireland but to be below the standard of an otherwise comparable area in Scotland.
The Genera of Trichotheliaceae
Authors: McCarthy P. M. , Malcolm W. M. 
Published: September 2002

AbstractRecent revisions of generic relationships in the pyrenocarpous lichen family Trichotheliaceae by J. Hafellner & K. Kalb (based on perithecial pigmentation and ascus structure) and R. C. Harris (based on morphological, chemical and environmental trends) are assessed. However, most of their conclusions are rejected because the authors used shared or variable characters, insufficient specimens and highly disjointed groups of species.
Studies on the Lichen Genus Sticta (Schreber) Ach. IV. New Zealand Species
Authors: Galloway D. J. 
Published: September 2002

AbstractThirteen species of the lichen genus Sticta (Schreber) Ach., are recognized in the New Zealand flora viz.: S. babingtonii, S. caliginosa, S. colinii sp. nov., S. cinereoglauca, S. filix, S. fuliginosa, S. lacera, S. latifrons, S. limbata, S. martinii, S. squamata, S. subcaperata and S. sublimbata. A key to species, synonymy and typification, descriptions of all taxa, biogeographical affinities and distribution maps are presented. Sticta livida is excluded from the New Zealand flora.
The Effect of Simulated Acid Rain on Surface Morphology and n-alkane Composition of Pseudevernia Furfuracea
Authors: Piervittori R. , Usai L. , Alessio F. , Maffei M. 
Published: September 2002

AbstractThe effects of simulated sulphuric acid rain were investigated, under controlled laboratory conditions, on the surface structure and n-alkane composition of the lichen Pseudevernia furfuracea. Thalli were collected from Larix decidua bark in a wood in a Piedmont alpine valley and treated with three concentrations of H2SO4. The response to simulated acid rain was a clear change in the quantitative alkane composition, with a decreasing trend observed for C28 and C30 with increasing sulphuric acid concentration. From a morphological point of view, a progressive reduction of the surface amorphous layer was observed as a consequence of the exposure of thalli to the acid rain treatments.