bluuebunny/crossref_metadata_2025_split huggingface dataset:
Burkholderia pseudomallei stimulates low interleukin-8 production in the human lung epithelial cell line A549
Authors: UTAISINCHAROEN P , ANUNTAGOOL N , ARJCHAROEN S , LENGWEHASATIT I , LIMPOSUWAN K , CHAISURIYA P , SIRISINHA S 
Published: September 2004

SUMMARY
Melioidosis is a life-threatening disease caused by Burkholderia pseudomallei. The lung is the most commonly affected organ, resulting in abscess formation in patients with chronic melioidosis. Previous study has shown that B. pseudomallei was able to invade and multiply in epithelial cells. In the present study, we have demonstrated that B. pseudomallei is able to stimulate interleukin 8 (IL-8) production from the human alveolar lung epithelium cell line A549. However, the level of IL-8 production was significantly lower than when the cells were infected with other Gram-negative bacteria such as Salmonella enterica serovar Typhi (S. typhi) which were used for comparison. The degree of IκBα degradation in the B. pseudomallei-infected cells was lower than that of the S. typhi-infected cells, suggesting that B. pseudomallei is also a poorer cell activator. Inhibition of B. pseudomallei invasion by cytochalasin D did not interfere with either IL-8 production or IκBα degradation, indicating that bacterial uptake is not required for the production of this chemokine. Thus, it appears that the signalling initiated by the interaction of B. pseudomallei with the epithelial cell surface is sufficient for epithelial cell activation.
Stem wood properties of Populus tremuloides, Betula papyrifera and Acer saccharum saplings after 3 years of treatments to elevated carbon dioxide and ozone
Authors: Kaakinen Seija , Kostiainen Katri , Ek Fredrik , Saranpää Pekka , Kubiske Mark E. , Sober Jaak , Karnosky David F. , Vapaavuori Elina 
Published: September 2004

AbstractThe aim of this study was to examine the effects of elevated carbon dioxide [CO2] and ozone [O3] and their interaction on wood chemistry and anatomy of five clones of 3‐year‐old trembling aspen (Populus tremuloides Michx.). Wood chemistry was studied also on paper birch (Betula papyrifera Marsh.) and sugar maple (Acer saccharum Marsh.) seedling‐origin saplings of the same age. Material for the study was collected from the Aspen Free‐Air CO2 Enrichment (FACE) experiment in Rhinelander, WI, USA, where the saplings had been exposed to four treatments: control (C; ambient CO2, ambient O3), elevated CO2 (560 ppm during daylight hours), elevated O3 (1.5 × ambient during daylight hours) and their combination (CO2+O3) for three growing seasons (1998–2000). Wood chemistry responses to the elevated CO2 and O3 treatments differed between species. Aspen was most responsive, while maple was the least responsive of the three tree species. Aspen genotype affected the responses of wood chemistry and, to some extent, wood structure to the treatments. The lignin concentration increased under elevated O3 in four clones of aspen and in birch. However, elevated CO2 ameliorated the effect. In two aspen clones, nitrogen in wood samples decreased under combined exposure to CO2 and O3. Soluble sugar concentration in one aspen clone and starch concentration in two clones were increased by elevated CO2. In aspen wood, α‐cellulose concentration changed under elevated CO2, decreasing under ambient O3 and slightly increasing under elevated O3. Hemicellulose concentration in birch was decreased by elevated CO2 and increased by elevated O3. In aspen, elevated O3 induced statistically significant reductions in distance from the pith to the bark and vessel lumen diameter, as well as increased wall thickness and wall percentage, and in one clone, decreased fibre lumen diameter. Our results show that juvenile wood properties of broadleaves, depending on species and genotype, were altered by atmospheric gas concentrations predicted for the year 2050 and that CO2 ameliorates some adverse effects of elevated O3 on wood chemistry.
Variation in climate warming along the migration route uncouples arrival and breeding dates
Authors: Ahola Markus , Laaksonen Toni , Sippola Katja , Eeva Tapio , Rainio Kalle , Lehikoinen Esa 
Published: September 2004

AbstractMigratory species are of special concern in the face of global climate change, since they may be affected by changes in the wintering area, along the migration route and at the breeding grounds. Here we show that migration and breeding times of a trans‐Saharan migrant, the pied flycatcher Ficedula hypoleuca, closely follow local temperatures along the migration route and at the breeding grounds. Because of differences in long‐term temperature trends of short within‐spring periods, the migration period and the time interval between migration and breeding dates of this species have extended in SW Finland. Temperatures in northern parts of Central Europe have risen at the time when the first migrants arrive there, facilitating their migration northward. Temperatures later in the spring have not changed, and the last individuals arrive at the same time as before. The timing of breeding has not advanced because temperatures at the breeding site after arrival have not changed. These results show that the pied flycatchers can speed up their migration in response to rising temperatures along the migration route. Our results strongly indicate that the effects of climate change have to be studied at the appropriate time and geographical scales for each species and population concerned.
Simulation of potential range expansion of oak disease caused byPhytophthora cinnamomiunder climate change
Authors: Bergot Magali , Cloppet Emmanuel , Pérarnaud Victorine , Déqué Michel , Marçais Benoît , Desprez‐Loustau Marie‐Laure 
Published: September 2004

AbstractThis study examines the effects of climate warming on one of the most widely distributed and destructive forest pathogens,Phytophthora cinnamomi. In Europe, the winter survival of the pathogen is the dominant cue for the development of the disease it causes to oaks, especiallyQuercus roburandQ. rubra. The potential pathogen and disease geographic ranges were compared in France between two reference periods, 1968–1998 and 2070–2099. Simulations were obtained by combining a physiologically based approach predicting the pathogen winter survival in relation to microhabitat temperature (in the phloem of infected trees) with a regionalized climatic scenario derived from a global circulation model. Positive anomalies in winter temperatures calculated with this scenario were in the range 0.5–5°C between the periods 2070–2099 and the 1968–1998, according to sites and months. As a consequence, higher annual rates ofP. cinnamomisurvival were predicted, resulting in a potential range expansion of the disease of one to a few hundred kilometers eastward from the Atlantic coast within one century. Based on this example, the study emphasizes the need of a better understanding of the impacts of global change on the biotic constraint constituted by plant pathogens.
C3 grasses have higher nutritional quality than C4 grasses under ambient and elevated atmospheric CO2
Authors: Barbehenn Raymond V. , Chen Zhong , Karowe David N. , Spickard Angela 
Published: September 2004

AbstractGrasses with the C3 photosynthetic pathway are commonly considered to be more nutritious host plants than C4 grasses, but the nutritional quality of C3 grasses is also more greatly impacted by elevated atmospheric CO2 than is that of C4 grasses; C3 grasses produce greater amounts of nonstructural carbohydrates and have greater declines in their nitrogen content than do C4 grasses under elevated CO2. Will C3 grasses remain nutritionally superior to C4 grasses under elevated CO2 levels? We addressed this question by determining whether levels of protein in C3 grasses decline to similar levels as in C4 grasses, and whether total carbohydrate : protein ratios become similar in C3 and C4 grasses under elevated CO2. In addition, we tested the hypothesis that, among the nonstructural carbohydrates in C3 grasses, levels of fructan respond most strongly to elevated CO2. Five C3 and five C4 grass species were grown from seed in outdoor open‐top chambers at ambient (370 ppm) or elevated (740 ppm) CO2 for 2 months. As expected, a significant increase in sugars, starch and fructan in the C3 grasses under elevated CO2 was associated with a significant reduction in their protein levels, while protein levels in most C4 grasses were little affected by elevated CO2. However, this differential response of the two types of grasses was insufficient to reduce protein in C3 grasses to the levels in C4 grasses. Although levels of fructan in the C3 grasses tripled under elevated CO2, the amounts produced remained relatively low, both in absolute terms and as a fraction of the total nonstructural carbohydrates in the C3 grasses. We conclude that C3 grasses will generally remain more nutritious than C4 grasses at elevated CO2 concentrations, having higher levels of protein, nonstructural carbohydrates, and water, but lower levels of fiber and toughness, and lower total carbohydrate : protein ratios than C4 grasses.
Phylogenetic relationships between disjunctly occurring groups of Tristicha trifaria (Podostemaceae)
Authors: Kita Yoko , Kato Masahiro 
Published: September 2004

AbstractAim  To reveal the phylogeographic relationship of disjunct specimens of Tristicha trifaria (Bory ex Willd.) Spreng., a member of the Podostemaceae river‐weed family, which is distributed exceptionally widely, but disjunctly, in Africa and the Americas.Location  Brazil, Mexico, Ghana, Tanzania and Madagascar.Methods  The chloroplast matK and rbcL genes, a trnK intron, the trnS‐trnG intergenic spacer (IGS), the two IGSs of trnT‐trnL‐trnF, a trnL intron, and nuclear ribosomal ITS regions were sequenced and analysed. Phylogenetic analyses were conducted using maximum likelihood and maximum parsimony methods.Results  The T. trifaria samples analysed were separated into two groups in a rooted tree based on a combined matK/rbcL/ITS dataset; one contained the West African and all of the American samples, and the other contained the East African and Madagascan samples. An unrooted tree obtained from a combined analysis of all the chloroplast DNA and nuclear ITS data showed that a sample from West Africa was sister to an American T. trifaria group.Main conclusions  The American and West African T. trifaria are closely related, despite the great distance between their locations. This observation, along with a tree of the whole Tristichoideae subfamily and estimated divergence times, suggests that an ancestor of T. trifaria migrated from Asia to Africa during the early Tertiary, and that this was followed by further westward migration to the Americas at the end of the Miocene or in the early Pliocene.
Evolution and biogeography of the austral genusPhyllocladus(Podocarpaceae)
Authors: Wagstaff Steven J. 
Published: September 2004

AbstractAim To infer evolutionary relationships within the genusPhyllocladusand among its close relatives by phylogenetic analysis of DNA sequences. Interpret the inferred relationships in association with the fossil record to examine the origin and diversification of the genus.Location Australasia.Methods Phylogenetic analyses ofrbcL,matKand internal transcribed spacer (ITS) sequences representing all of the extant species ofPhyllocladusand a selection of outgroups from Podocarpaceae and Araucariaceae.Results TherbcLandmatKsequences exhibit little variation withinPhyllocladus, but ally its members to Podocarpaceae although its immediate sister remains unclear. The ITS sequences resolve all five species ofPhyllocladusand two intraspecific ecotypes ofP. alpinus.Main conclusions Phyllocladusforms a distinct lineage that diverged early in the evolutionary history of Podocarpaceae. The fossil record indicates that the genus was more widely distributed and morphologically diverse during the early Tertiary than at present. Although of Mesozoic origin, the level of sequence variation withinPhyllocladussuggests that the extant species radiated during the late Tertiaryc.6.3 ± 0.9 Ma. New Zealand is the present centre of species diversity.
An evaluation of methods for modelling species distributions
Authors: Segurado Pedro , Araújo Miguel B. 
Published: September 2004

AbstractAim  Various statistical techniques have been used to model species probabilities of occurrence in response to environmental conditions. This paper provides a comprehensive assessment of methods and investigates whether errors in model predictions are associated to specific kinds of geographical and environmental distributions of species.Location  Portugal, Western Europe.Methods  Probabilities of occurrence for 44 species of amphibians and reptiles in Portugal were modelled using seven modelling techniques: Gower metric, Ecological Niche Factor Analysis, classification trees, neural networks, generalized linear models, generalized additive models and spatial interpolators. Generalized linear and additive models were constructed with and without a term accounting for spatial autocorrelation. Model performance was measured using two methods: sensitivity and Kappa index. Species were grouped according to their spatial (area of occupancy and extent of occurrence) and environmental (marginality and tolerance) distributions. Two‐way comparison tests were performed to detect significant interactions between models and species groups.Results  Interaction between model and species groups was significant for both sensitivity and Kappa index. This indicates that model performance varied for species with different geographical and environmental distributions. Artificial neural networks performed generally better, immediately followed by generalized additive models including a covariate term for spatial autocorrelation. Non‐parametric methods were preferred to parametric approaches, especially when modelling distributions of species with a greater area of occupancy, a larger extent of occurrence, lower marginality and higher tolerance.Main conclusions  This is a first attempt to relate performance of modelling techniques with species spatial and environmental distributions. Results indicate a strong relationship between model performance and the kinds of species distributions being modelled. Some methods performed generally better, but no method was superior in all circumstances. A suggestion is made that choice of the appropriate method should be contingent on the goals and kinds of distributions being modelled.
Biogeographical analysis of species of the tribe Cytiseae (Fabaceae) in the Iberian Peninsula and Balearic Islands
Authors: Gómez‐González Susana , Cavieres Lohengrin A. , Teneb Ernesto A. , Arroyo Juan 
Published: September 2004

AbstractAim  To analyse quantitatively the biogeographical distribution pattern of species of the Cytiseae Bercht. & J. Presl (= Genisteae Benth.) tribe in the Iberian Peninsula and the Balearic Islands, and to identify environmental variables related to the distributional patterns.Location  Iberian Peninsula and Balearic Islands, using the 61 administrative provinces as operational geographical units.Methods  In order to identify chorotypes (groups of species with similar geographical distribution), we performed a upgma classification based on the similarity index of Baroni‐Urbani & Buser. The method of McCoy et al. [Ecology67 (1986), 749] enabled us to detect the significant groups and to differentiate them from those groupings that could be generated at random. Logistic regression analyses and environmental gradient analyses (DCA and CCA) were performed in order to find the relationships between the environmental variables and the observed distributional patterns.Results  Sixteen chorotypes were obtained between the Cytiseae species of the Iberian Peninsula and the Balearic Islands. The thermal variables showed the greatest influence in species distribution. Specifically, temperatures (maximum, minimum and mean) of the coldest months were associated with the majority of the chorotypes.Main conclusions  The species of the Cytiseae tribe were not randomly distributed in space, and can be classified in groups of species with common distributional patterns. The importance of cold tolerance in the distribution of these species, as well as their preference for acidic soils, was demonstrated. Certain general tendencies seem to exist with respect to the distribution of the biota in the Iberian Peninsula, and these seem to be independent of the taxonomic groups involved and to be determined by convergent macroclimatic factors.
Distributional modelling and parsimony analysis of endemicity of Senecio in the Mediterranean‐type climate area of Central Chile
Authors: Rovito Sean M. , Arroyo Mary T.K. , Pliscoff Patricio 
Published: September 2004

AbstractAim  Floristic blocks and areas of endemism resulting from a parsimony analysis of endemicity (PAE) using raw floristic data versus data generated from distributional modelling for 130 species in the genus Senecio Tourn. ex L. distributed in the Mediterranean‐type climate area of Central Chile were compared, and the results were used to identify conservation priorities for the flora of the region.Location  Central Chile, between 30° and 38° S.Methods  Using herbarium records, a species × area matrix consisting of presence/absence data was constructed from a 0.5° × 0.5° grid. Distributional modelling techniques incorporating vegetation formations, elevation and the contagion index were used to interpolate floristic composition of poorly known areas. Parsimony analysis of endemicity was used to identify floristic blocks and areas of endemism.Results  Using the number of most parsimonious trees as an index, distributional modelling greatly optimized the results of the PAE analysis. Three floristic blocks and four areas of endemism were suggested based on the PAE results using potential distribution data not incorporating the contagion index, while four blocks and two areas of endemism were suggested from the PAE results using potential distribution data incorporating the contagion index. Floristic blocks for the northern coast, southern Andes, and northern/central Andes were found, with some blocks showing divisions within them representing distinct geographic subunits. Major breaks between and within floristic blocks were identified at 32.5°–33° S and 34.5°–35° S.Main conclusions  The floristic blocks identified with the distributional modelling and PAE correspond well to results from some previous studies and support hypothesized biogeographic divisions within Central Chile. The results were similar to those obtained from parallel analysis of the entire tree flora of Central Chile. The vegetative formation‐based distributional modelling produced robust and reproducible results when used along with PAE, especially when the contagion index was incorporated, and is a useful technique for area classification. The results demonstrate the utility of Senecio as an indicator genus for biogeography and conservation in southern South America.
Amplified fragment length polymorphism (AFLP) suggests old and recent immigration into the Alps by the arctic‐alpine annual Comastoma tenellum (Gentianaceae)
Authors: Schönswetter Peter , Tribsch Andreas , Niklfeld Harald 
Published: September 2004

AbstractAim  This study aims to elucidate the phylogeography of the arctic‐alpine annual Comastoma tenellum (Rottb.) Toyok. (Gentianaceae) and to unravel the history of its immigration into the Alps.Location  Although samples from Alaska and Central Asia were also included, our study focusses on Europe, especially on the Alps.Methods  We applied amplified fragment length polymorphism (AFLP) fingerprinting on 37 populations (162 individuals) of C. tenellum and analysed the results phenetically.Results  As C. tenellum is mainly inbreeding, there is typically little to no intrapopulational genetic variation. Two populations from Alaska and Altai are strongly separated from all other accessions. The majority of the populations from the Alps group together with high bootstrap support. They fall into an unsupported Alps I group (northwards of Gran Paradiso) and a well‐supported Alps II group (south‐western Alps). The remaining European populations form a weakly‐supported branch constituting accessions from the Carpathians, Scandinavia and two populations from the Eastern Alps.Main conclusions  Comastoma tenellum reached the Alps at least twice. The first immigration event resulted in a lineage that is clearly separated from the other European accessions. The immigration must have occurred well before the last glaciation because this lineage shows further phylogeographical structuring into two groups (Alps II in the south‐western Alps and Alps I in the rest of the Alps). This pattern is presumably due to isolation in different glacial refugia. In addition to the old immigration event, the species reached the Alps in recent times either from Scandinavia or from the Carpathians via long‐distance dispersal. These immigrations resulted in (at least) two populations that are spatially small and poor in individuals.
Diversity and distribution of ferns in sub‐Saharan Africa, Madagascar and some islands of the South Atlantic
Authors: Aldasoro J. J. , Cabezas F. , Aedo C. 
Published: September 2004

AbstractAim This paper reports the diversity and endemism patterns of African ferns, and explores the potential role of diversity refuges and environmental and historical factors in the shaping of these patterns.Material and locations The extant fern taxa occupying Africa south of the Sahara, Madagascar and some islands of the South Atlantic.Methods The number of taxa in each area or operational geographical unit (OGU) was scored, and the correlation between this number and physical and climatic variables analysed by standard pairwise and stepwise multiple regression analysis (SPR and SMR). The effects of biological factors such as dispersal capacity, reproductive biology, genetic features and certain physiological adaptations were evaluated by comparing the number of species in each OGU. Floral affinities among OGUs were analysed using non‐metric multi‐dimensional scaling (NMS) and parsimonic analysis of dispersion (PAD), and compared withβ‐turnover and inter‐OGU distances.Results OGU area, elevation and the distance between refuges determined the composition of local floras, but only greater OGU area and the existence of higher maximum elevations increased species richness. The distance between refuges also affected the number of endemic species, especially on islands. The biological features studied only slightly influenced fern distribution. The main climatic predictor of species number was humidity. SPR and SMR revealed three main groups of ferns with different ecological trends. NMS and PAD analyses separated the four areas of highest diversity in Africa, three of which are inhabited by ferns with distinct ecological requirements. The fourth area was Madagascar, which shows an accumulation of endemic and relict diversity that is not easy to explain.Main conclusions The distribution of ferns in Africa has been influenced by refuges. These probably allowed many species to recolonize the neighbouring areas after the extinctions of the Pleistocene. Three major components were detected in the African flora: Guinea‐Congolian thermophilous, cold‐tolerant Afro‐montane, and Southern drought‐tolerant elements. These are related to the three main refuge areas, i.e. the Gulf of Guinea area, the eastern tropical region, and the Cape region. Endemicity in ferns was found to be lower than that of seed plants due to the higher dispersability of fern spores. The distance between OGUs seems to be the main predictor of the number of endemic fern species these areas contain.