bluuebunny/crossref_metadata_2025_split huggingface dataset:
β7‐integrin‐independent enhancement of mucosal and systemic anti‐HIV antibody responses following combined mucosal and systemic gene delivery
Authors: Goodsell Amanda , Zhou Fengmin , Gupta Soumi , Singh Manmohan , Malyala Padma , Kazzaz Jina , Greer Catherine , Legg Harold , Tang Tony , Zur Megede January , Srivastava Ranjana , Barnett Susan W. , Donnelly John J. , Luciw Paul A. , Polo John , O'Hagan Derek T. , Vajdy Michael 
Published: October 2007

SummaryVaccination strategies that can block or limit heterosexual human immunodeficiency virus (HIV) transmissions to local and systemic tissues are the goal of much research effort. Herein, in a mouse model, we aimed to determine whether the enhancement of antibody responses through mucosal and systemic immunizations, previously observed with protein‐based vaccines, applies to immunizations with DNA‐ or RNA‐based vectors. Intranasal (i.n.) followed by intramuscular (i.m.) immunizations (i.n./i.m.) with polylactide‐coglycolide (PLG)‐DNA microparticles encoding HIV‐gag (PLG‐DNA‐gag) significantly enhanced serum antibody responses, compared with i.m., i.n. or i.m. followed by i.n. (i.m./i.n.) immunizations. Moreover, while i.n./i.m., i.n. or i.m./i.n. immunizations with PLG‐DNA‐gag resulted in genital tract antibody responses, i.m. immunizations alone failed to do so. Importantly, β7‐deficient mice developed local and systemic antibody responses following i.n./i.m. immunization, or immunization via any other route, similar to those of wild‐type mice. To compare the DNA with an RNA delivery system, immunizations were performed with VEE/SIN‐gag replicon particles, composed of Venezuelan equine encephalitis virus (VEE) replicon RNA and Sindbis surface structure (SIN). i.n./i.m., compared with any other immunizations, i.n./i.m. immunization with VEE/SIN‐gag resulted in enhanced genital tract but not serum antibody responses. These data show for the first time that mucosal followed by systemic immunizations with gene delivery systems enhance B‐cell responses independent of the mucosal homing receptors α4β7 and αEβ7.
The effects of livestock grazing on foliar arthropods associated with bird diet in upland grasslands of Scotland
Authors: Dennis Peter , Skartveit John , McCracken David I. , Pakeman Robin J. , Beaton Katy , Kunaver Anja , Evans Darren M. 
Published: October 2007

Summary

Upland biotopes have conservation importance for their typical plant and animal species. Recently, the condition of upland habitats has deteriorated with associated declines in many upland birds. Grazing by increased densities of sheep has been implicated in these changes. Studies in lowland agricultural land have shown a link between declines in bird populations and the availability of arthropod prey.
We studied the effect of three grazing regimes and an ungrazed control, each replicated six times in a total of 24 3·3‐ha plots, on the numbers and overall biomass of foliar arthropods in upland grassland in the Southern Highlands.
The three grazed treatments of the experiment were stocked with the commercial stocking density of sheep, one‐third of the commercial stocking density by sheep only and one‐third of the commercial stocking density by sheep and cattle.
Arthropod groups recognized as components of the diet of moorland birds were sampled by motorized suction sampler and sweep net. Arthropod numbers were unaffected by grazing treatments 6 months after grazing commenced. Significant grazing treatment effects on spiders, bugs and beetles were observed in years 2 and 3, with higher numbers in the less‐grazed treatments, but no such effect on brachyceran flies, caterpillars and craneflies.
A residual maximum likelihood (REML) analysis related the numbers of spiders, bugs, beetles, craneflies and caterpillars to either the stocking density of sheep or an interaction of sheep with year. The analysis related bugs and brachyceran flies to an interaction between cattle stocking density and year.
Estimated total biomass of foliar arthropods increased significantly with decreasing grazing intensity in years 2 and 3 and biomass in the ungrazed treatment was approximately twice that in the commercially grazed treatment. The REML analysis related biomass to the stocking density of sheep and both the stocking density of sheep and of cattle in an interaction with year.
Synthesis and applications. We demonstrated that the stocking density and inclusion of cattle grazing affects the numbers and biomass of particular foliar arthropods in the uplands of Scotland. Grazing management is important not only for the conservation of arthropods per se but also as food for insectivorous birds of conservation concern.
Habitat invasions by alien plants: a quantitative comparison among Mediterranean, subcontinental and oceanic regions of Europe
Authors: Chytrý Milan , Maskell Lindsay C. , Pino Joan , Pyšek Petr , Vilà Montserrat , Font Xavier , Smart Simon M. 
Published: October 2007

Summary

Although invasions by alien plants are major threats to the biodiversity of natural habitats, individual habitats vary considerably in their susceptibility to invasion. Therefore the risk assessment procedures, which are used increasingly by environmental managers to inform effective planning of invasive plant control, require reliable quantitative information on the extent to which different habitats are susceptible to invasion. It is also important to know whether the levels of invasion in different habitats are locally specific or consistent among regions with contrasting climate, flora and history of human impact.
We compiled a database of 52 480 vegetation plots from three regions of Europe: Catalonia (Mediterranean–submediterranean region), Czech Republic (subcontinental) and Great Britain (oceanic). We classified plant species into neophytes, archaeophytes and natives, and calculated the proportion of each group in 33 habitats described by the European Nature Information System (EUNIS) classification.
Of 545 alien species found in the plots, only eight occurred in all three regions. Despite this large difference in species composition, patterns of habitat invasions were highly consistent between regions. None or few aliens were found in environmentally extreme and nutrient‐poor habitats, e.g. mires, heathlands and high‐mountain grasslands. Many aliens were found in frequently disturbed habitats with fluctuating nutrient availability, e.g. in man‐made habitats. Neophytes were also often found in coastal, littoral and riverine habitats.
Neophytes were found commonly in habitats also occupied by archaeophytes. Thus, the number of archaeophytes can be considered as a good predictor of the neophyte invasion risk. However, neophytes had stronger affinity to wet habitats and disturbed woody vegetation while archaeophytes tended to be more common in dry to mesic open habitats.
Synthesis and applications. The considerable inter‐regional consistency of the habitat invasion patterns suggests that habitats can be used as a good predictor for the invasion risk assessment. This finding opens promising perspectives for the use of spatially explicit information on habitats, including scenarios of future land‐use change, to identify the areas of highest risk of invasion.
Vascular plant and Orthoptera diversity in relation to grassland management and landscape composition in the European Alps
Authors: Marini Lorenzo , Fontana Paolo , Scotton Michele , Klimek Sebastian 
Published: October 2007

Summary

Several recent studies have considered the relative effects of local vs. landscape factors on diversity of several animal taxa in grasslands. However, very few have considered vascular plant or Orthoptera species, both of which are important biotic components of grassland ecosystems. The general aim of this study was to determine the effect of grassland management and landscape composition, and their potential interactions, on diversity patterns of vascular plants and Orthoptera in Alpine hay meadows.
We considered three groups of management regimes defined by different amounts of fertilizer nitrogen applied and cutting frequency: (i) extensive, (ii) low intensive and (iii) intensive meadows situated in different landscape contexts. To evaluate the relative importance of meadow management and landscape composition on diversity patterns, we applied analysis of covariance and variation partitioning analyses.
Diversity patterns of both taxonomic groups were affected primarily by grassland management. The extensive management regime was most suitable for conserving high species richness of both taxonomic groups. The intensive meadows were characterized by plant communities dominated by a few ruderal and competitor species, and by Orthoptera communities composed of only a few abundant Caelifera species (e.g. Chorthippus parallelus), while Ensifera species had very low individual densities.
Regarding the landscape determinants, plant diversity patterns were not significantly related to any landscape composition variables. In contrast, a high proportion of urban elements and grassland in the surrounding landscape (radius 500 m) affected Orthoptera species richness negatively.
Synthesis and applications. The implementation of well‐targeted agri‐environment schemes for compensation payments against intensification and abandonment of extensive hay meadows seems to be a promising tool to protect both taxonomic groups. In this context, we suggest that the existing Swiss ecological compensation area (ECA) hay meadow agri‐environment scheme, which requires at least one cut every year and no fertilizer application, might also be suitable for the Italian Alps. Moreover, the significant influence of landscape composition on Orthoptera diversity suggests that the effectiveness of measures applied at a field scale may be improved by integration of protected area schemes, promoting extensive management at a farm scale.
Phylogeography of Iris missouriensis (Iridaceae) based on nuclear and chloroplast markers
Authors: CORNMAN R. SCOTT , ARNOLD MICHAEL L. 
Published: October 2007

AbstractWe investigated the phylogeography of Iris missouriensis (Iridaceae), which is widely distributed in western North America. We utilized transposon display and DNA sequencing to quantify nuclear and chloroplast genetic structure. Our objectives were (i) to characterize the geographic structure of genetic variation throughout the species range, (ii) to test whether both margins of the range show reduced genetic diversity as predicted by north–south expansion and contraction associated with climate change, and (iii) to determine whether the subspecies Iris missouriensis ssp. longipetala is genetically distinct. We found that genetic diversity was significantly lower in the northern part of the range but was not significantly different between the central and southern regions, indicating greater stability of the southern margin vs. the northern. Among‐population differentiation was high (ΦPT = 0.52). The largest divisions in each marker set were concordant and separated the southern Rocky Mountains and Basin and Range provinces from the remainder of the range. The boundaries of this phylogeographic break do not coincide with gaps in present‐day distributions or phylogeographic breaks identified in other species, and may indicate a measure of reproductive isolation. Consistent with current treatments, we did not find support for the taxonomic placement of I. missourienis ssp. longipetala as a distinct species. Although transposon display has been used to investigate relationships among crop accessions and their wild relatives, to our knowledge, this is the first use of these markers for population‐level phylogeography of a nonmodel species and further demonstrates their utility in species recalcitrant to amplified fragment length polymorphism protocols.
Genetic analysis of potential postglacial watershed crossings in Central Europe by the bullhead (Cottus gobioL.)
Authors: VONLANTHEN P. , EXCOFFIER L. , BITTNER D. , PERSAT H. , NEUENSCHWANDER S. , LARGIADÈR C. R. 
Published: October 2007

AbstractNatural colonizations across watersheds have been frequently proposed to explain the present distributions of many freshwater fish species. However, detailed studies of such potential watershed crossings are still missing. Here, we investigated potential postglacial watershed crossings of the widely distributed European bullhead (Cottus gobioL.) in two different areas along the Rhine–Rhône watershed using detailed genetic analysis. The main advantage of studying bullheads vs. other freshwater fish species is that their distribution has been lightly influenced by human activities and as such, interpretations of colonization history are not confounded by artificial transplantations. The genetic analyses of eight microsatellite loci revealed strong genetic similarities between populations of both sides of the Rhine–Rhône watershed in the Lake Geneva area, giving strong evidence for a natural watershed crossing of bullheads from the upper Rhine drainage into the Rhône drainage in the Lake Geneva area likely facilitated by the retreat of the glaciers after the last glacial maximum some 20 000 years ago. Populations from the Lake Geneva basin were genetically more similar to populations from across the watershed in the upper Rhine drainage than to populations further downstream in the lower Rhône. In contrast, populations from Belfort, an area, which was not covered by ice during the last glacial maximum, showed strong genetic differentiation between populations of the upper Rhine and Rhône drainages. Based on our results on the bullhead, we propose that glacial retreat may have eased the dispersal of numerous European freshwater fish species across several geological boundaries.
Standardizing methods to address clonality in population studies
Authors: ARNAUD‐HAOND S. , DUARTE C. M. , ALBERTO F. , SERRÃO E. A. 
Published: October 2007

AbstractAlthough clonal species are dominant in many habitats, from unicellular organisms to plants and animals, ecological and particularly evolutionary studies on clonal species have been strongly limited by the difficulty in assessing the number, size and longevity of genetic individuals within a population. The development of molecular markers has allowed progress in this area, and although allozymes remain of limited use due to their typically low level of polymorphism, more polymorphic markers have been discovered during the last decades, supplying powerful tools to overcome the problem of clonality assessment. However, population genetics studies on clonal organisms lack a standardized framework to assess clonality, and to adapt conventional data analyses to account for the potential bias due to the possible replication of the same individuals in the sampling. Moreover, existing studies used a variety of indices to describe clonal diversity and structure such that comparison among studies is difficult at best. We emphasize the need for standardizing studies on clonal organisms, and particularly on clonal plants, in order to clarify the way clonality is taken into account in sampling designs and data analysis, and to allow further comparison of results reported in distinct studies. In order to provide a first step towards a standardized framework to address clonality in population studies, we review, on the basis of a thorough revision of the literature on population structure of clonal plants and of a complementary revision on other clonal organisms, the indices and statistics used so far to estimate genotypic or clonal diversity and to describe clonal structure in plants. We examine their advantages and weaknesses as well as various conceptual issues associated with statistical analyses of population genetics data on clonal organisms. We do so by testing them on results from simulations, as well as on two empirical data sets of microsatellites of the seagrasses Posidonia oceanica and Cymodocea nodosa. Finally, we also propose a selection of new indices and methods to estimate clonal diversity and describe clonal structure in a way that should facilitate comparison between future studies on clonal plants, most of which may be of interest for clonal organisms in general.
Diversity of fungi in hair roots of Ericaceae varies along a vegetation gradient
Authors: BOUGOURE DAMIAN S. , PARKIN PAMELA I. , CAIRNEY JOHN W. G. , ALEXANDER IAN J. , ANDERSON IAN C. 
Published: October 2007

AbstractEricaceous dwarf shrubs including Calluna vulgaris and Vaccinium spp. occur both in open heathland communities and in forest ecosystems as understorey vegetation. Ericaceous shrubs were once thought to form ericoid mycorrhizal associations with a relatively narrow range of ascomycetous fungi closely related to, and including, Rhizoscyphus ericae. However, perceptions have recently changed since the realization that a broader range of ascomycete fungi, and in some cases basidiomycete fungi, can also form associations with the roots of ericaceous plants. We used a combination of molecular approaches, including denaturing gradient gel electrophoresis, terminal restriction fragment length polymorphism, cloning and sequencing, to investigate the diversity of fungi associated with C. vulgaris roots collected across a heathland/native Scots pine forest vegetation gradient. We also determined differences in fungal community composition between roots of co‐occurring C. vulgaris and Vaccinium myrtillus in the forest understorey. Collectively, the data show that a large diversity of potentially ericoid mycorrhizal fungal taxa associate with roots of C. vulgaris and V. myrtillus, and that ascomycetes were about 2.5 times more frequent than basidiomycetes. The assemblages of fungi associated with C. vulgaris and V. myrtillus were different. In addition, the community of fungi associated with C. vulgaris hair roots was different for samples collected from the forest, open heathland and a transition zone between the two. This separation was partly, but not entirely, due to the occurrence of typical ectomycorrhizal basidiomycetes associated with the hair roots of C. vulgaris in the forest understorey. These data demonstrate that forest understorey ericaceous shrubs associate with a diverse range of ascomycete and basidiomycete taxa, including typical ectomycorrhizal basidiomycetes.
Population genetics and phylogeography of sea turtles
Authors: BOWEN B. W. , KARL S. A. 
Published: October 2007

AbstractThe seven species of sea turtles occupy a diversity of niches, and have a history tracing back over 100 million years, yet all share basic life‐history features, including exceptional navigation skills and periodic migrations from feeding to breeding habitats. Here, we review the biogeographic, behavioural, and ecological factors that shape the distribution of genetic diversity in sea turtles. Natal homing, wherein turtles return to their region of origin for mating and nesting, has been demonstrated with mtDNA sequences. These maternally inherited markers show strong population structure among nesting colonies while nuclear loci reveal a contrasting pattern of male‐mediated gene flow, a phenomenon termed ‘complex population structure’. Mixed‐stock analyses indicate that multiple nesting colonies can contribute to feeding aggregates, such that exploitation of turtles in these habitats can reduce breeding populations across the region. The mtDNA data also demonstrate migrations across entire ocean basins, some of the longest movements of marine vertebrates. Multiple paternity occurs at reported rates of 0–100%, and can vary by as much as 9–100% within species. Hybridization in almost every combination among members of the Cheloniidae has been documented but the frequency and ultimate ramifications of hybridization are not clear. The global phylogeography of sea turtles reveals a gradient based on habitat preference and thermal regime. The cold‐tolerant leatherback turtle (Dermochelys coriacea) shows no evolutionary partitions between Indo‐Pacific and Atlantic populations, while the tropical green (Chelonia mydas), hawksbill (Eretmochelys imbricata), and ridleys (Lepidochelys olivaceavs.L. kempi) have ancient separations between oceans. Ridleys and loggerhead (Caretta caretta) also show more recent colonization between ocean basins, probably mediated by warm‐water gyres that occasionally traverse the frigid upwelling zone in southern Africa. These rare events may be sufficient to prevent allopatric speciation under contemporary geographic and climatic conditions. Genetic studies have advanced our understanding of marine turtle biology and evolution, but significant gaps persist and provide challenges for the next generation of sea turtle geneticists.
Population history of Berthelot's pipit: colonization, gene flow and morphological divergence in Macaronesia
Authors: ILLERA JUAN CARLOS , EMERSON BRENT C. , RICHARDSON DAVID S. 
Published: October 2007

AbstractThe fauna of oceanic islands provide exceptional models with which to examine patterns of dispersal, isolation and diversification, from incipient speciation to species level radiations. Here, we investigate recent differentiation and microevolutionary change in Berthelot's pipit (Anthus berthelotii), an endemic bird species inhabiting three Atlantic archipelagos. Mitochondrial DNA sequence data and microsatellite markers were used to deduce probable colonization pathway, genetic differentiation, and gene flow among the 12 island populations. Phenotypic differentiation was investigated based on eight biologically important morphological traits. We found little mitochondrial DNA variability, with only one and four haplotypes for the control region and cytochromeb, respectively. However, microsatellite data indicated moderate population differentiation (FST = 0.069) between the three archipelagos that were identified as genetically distinct units with limited gene flow. Both results, combined with the estimated time of divergence (2.5 millions years ago) from theAnthus campestris(the sister species), suggest that this species has only recently dispersed throughout these islands. The genetic relationships, patterns of allelic richness and exclusive alleles among populations suggest the species originally colonized the Canary Islands and only later spread from there to the Madeiran archipelago and Selvagen Islands. Differentiation has also occurred within archipelagos, although to a lesser degree. Gene flow was observed more among the eastern and central islands of the Canaries than between these and the western islands or the Madeiran Islands. Morphological differences were also more important between than within archipelagos. Concordance between morphological and genetic differentiation provided ambiguous results suggesting that genetic drift alone was not sufficient to explain phenotypic differentiation. The observed genetic and morphological differences may therefore be the result of differing patterns of selection pressures between populations, with Berthelot's pipit undergoing a process of incipient differentiation.