bluuebunny/crossref_metadata_2025 huggingface dataset:
Immediate and longer‐term effects of managed flooding on floodplain invertebrate assemblages in south‐eastern Australia: generation and maintenance of a mosaic landscape
Authors: BALLINGER ANDREA , NALLY RALPH MAC , LAKE P. S.
Published: June 2005

1. We compared assemblages of ground‐active, terrestrial beetles and spiders from different areas of river red gum Eucalyptus camaldulensis floodplain forest in subhumid, south‐eastern Australia before and for 2 years following a managed flood to determine whether the Flood Pulse Concept is an appropriate ecological model for this regulated, lowland river‐floodplain system.

2. Immediately following flooding, the abundance, species richness and biomass of beetles were greatest at sites that had been inundated for the longest period (approximately 4 months). The abundance, species richness and biomass of spiders were not reduced at sites that were flooded for 4 months compared with unflooded or briefly flooded areas. Sites recently flooded for several months had high densities of predatory, hygrophilic beetles (Carabidae) and spiders (Lycosidae).

3. Over the 2 years following the flood, beetles generally were more abundant at sites that had been inundated for longer. At all sampling times, the species richness of beetles at sites increased with the length of time sites were inundated, even before the flood. Neither the abundance nor species richness of spiders was related to duration of flooding.

4. The structure of beetle and spider assemblages at sites that were flooded for different lengths of time did not appear to converge monotonically over the 2 years after the flood.

5. Managed flooding promotes diversity of beetles and spiders both by providing conditions that create a ‘pulse’ in populations of hygrophilic specialists in the short term, and by creating subtle, persistent changes in forest‐floor conditions. Despite its monotypic canopy, river red gum floodplain forest is a habitat mosaic generated by differing inundation histories.
Soluble nitrogen and phosphorus excretion of exotic freshwater mussels (Dreissena spp.): potential impacts for nutrient remineralisation in western Lake Erie
Authors: CONROY JOSEPH D. , EDWARDS WILLIAM J. , PONTIUS RUTH A. , KANE DOUGLAS D. , ZHANG HONGYAN , SHEA JOHN F. , RICHEY JULIE N. , CULVER DAVID A.
Published: June 2005

1. Recent increases in phytoplankton biomass and the recurrence of cyanobacterial blooms in western Lake Erie, concomitant with a shift from a community dominated by zebra mussels (Dreissena polymorpha) to one dominated by quagga mussels (D. bugensis), led us to test for differences in ammonia‐nitrogen and phosphate‐phosphorus excretion rates of these two species of invasive molluscs.

2. We found significant differences in excretion rate both between size classes within a taxon and between taxa, with zebra mussels generally having greater nutrient excretion rates than quagga mussels. Combining measured excretion rates with measurements of mussel soft‐tissue dry weight and shell length, we developed nutrient excretion equations allowing estimation of nutrient excretion by dreissenids.

3. Comparing dreissenid ammonia and phosphate excretion with that of the crustacean zooplankton, we demonstrated that the mussels add to nitrogen and phosphorus remineralisation, shortening nitrogen and phosphorus turnover times, and, importantly, modify the nitrogen and phosphorus cycles in Lake Erie. The increased nutrient flux from dreissenids may facilitate phytoplankton growth and cyanobacterial blooms in well‐mixed and/or shallow areas of western Lake Erie.
Top‐down and bottom‐up influences on populations of a stream detritivore
Authors: MCINTOSH ANGUS R. , GREIG HAMISH S. , MCMURTRIE SHELLEY A. , NYSTRÖM PER , WINTERBOURN MICHAEL J.
Published: June 2005

1. Knowledge of the influence of predatory fish in detritus‐based stream food webs is poor. We tested whether larval abundance of the New Zealand leaf‐shredding caddisfly,Zelandopsyche ingens(family Oeconesidae), was affected by the presence of predatory brown trout,Salmo truttaand the abundance of their primary detrital resource (Nothofagusleaves).

2. The density ofZ. ingensand the biomass of leaves were determined in seven fishless streams and four trout streams in the Cass region, central South Island, on four occasions spanning 5 years.

3. Physicochemical conditions were similar in trout and fishless streams, butancovaindicated thatZ. ingensnumbers were positively related to leaf biomass and that caddisfly numbers were significantly greater in fishless streams than trout streams for any given biomass of leaf. The cases of trout stream larvae were also heavier per unit length than those in fishless streams.

4. Our results provide evidence for both top‐down and bottom‐up influences on a detritus‐based stream food web. Although stream detritivores may benefit from a habitat that provides both food and a degree of protection from predators, top‐down effects of predators on detritivore population abundance were still important. Thus, detrital resource availability may determine maximum attainable population size, whereas predation is likely to reduce the population to a level below that.
Abundance and biomass of heterotrophic microorganisms in Lake Tanganyika
Authors: PIRLOT SAMUEL , VANDERHEYDEN JULIE , DESCY JEAN‐PIERRE , SERVAIS PIERRE
Published: June 2005

1. This study focused on heterotrophic microorganisms in the two main basins (north and south) of Lake Tanganyika during dry and wet seasons in 2002. Bacteria (81% cocci) were abundant (2.28–5.30 × 106cells mL−1). During the dry season, in the south basin, bacterial biomass reached a maximum of 2.27 g C m−2and phytoplankton biomass was 3.75 g C m−2(integrated over a water column of 100 m).

2. Protozoan abundance was constituted of 99% of heterotrophic nanoflagellates (HNF). Communities of flagellates and bacteria consisted of very small but numerous cells. Flagellates were often the main planktonic compartment, with a biomass of 3.42–4.43 g C m−2. Flagellate biomass was in the same range and often higher than the total autotrophic biomass (1.60–4.72 g C m−2).

3. Total autotrophic carbon was partly sustained by the endosymbiotic zoochlorellaeStrombidium. These ciliates were present only in the euphotic zone and usually contributed most of the biomass of ciliates.

4. Total heterotrophic ciliate biomass ranged between 0.35 and 0.44 g C m−2. In 2002, heterotrophic microorganisms consisting of bacteria, flagellates and ciliates represented a large fraction of plankton. These results support the hypothesis that the microbial food web contributes to the high productivity of Lake Tanganyika.

5. As the sole source of carbon in the pelagic zone of this large lake is phytoplankton production, planktonic heterotrophs ultimately depend on autochthonous organic carbon, most probably dissolved organic carbon (DOC) from algal excretion.
Quantifying effects of phytoplankton on the heat budgets of two large limnetic enclosures
Authors: JONES IAN , GEORGE GLEN , REYNOLDS COLIN
Published: June 2005

1. The aestival heat budgets of two large limnetic enclosures within a small lake in the English Lake District were studied. During summer, these enclosures had different nutrient supplies and consequently different phytoplankton populations.

2. As initial temperature profiles were similar and the incoming surface heat and momentum fluxes for the two enclosures were identical, subsequent changes in the heat budget were assumed to be induced by the biological differences between the enclosures. The proposed mechanism is an increased surface absorption of solar radiation leading to extra surface warming and a consequent excess loss of heat to the atmosphere through long‐wave emittance and sensible and latent heat fluxes, conservatively estimated to be of the order of 10–30 W m−2.

3. Theoretical calculations show that potential effects on a heat budget could be considerably larger than those observed here. The inherent non‐linearity of the heat fluxes implies that such effects will be more important in warmer lakes than in colder ones.

4. Thermocline depth and strength were also altered by the response to differences in phytoplankton.

5. Any changes in climate or in nutrient loading from the catchment which substantially affect abundance or timing of phytoplankton populations in a lake will consequently also change the thermal structure of the lake.
Patterns of vegetative growth and gene flow in Rhizopogon vinicolor and R. vesiculosus (Boletales, Basidiomycota)
Authors: KRETZER ANNETTE M. , DUNHAM SUSIE , MOLINA RANDY , SPATAFORA JOSEPH W.
Published: June 2005

We have collected sporocarps and tuberculate ectomycorrhizae of both Rhizopogon vinicolor and Rhizopogon vesiculosus from three 50 × 100 m plots located at Mary's Peak in the Oregon Coast Range (USA); linear map distances between plots ranged from c. 1 km to c. 5.5 km. Six and seven previously developed microsatellite markers were used to map the approximate size and distribution of R. vinicolor and R. vesiculosus genets, respectively. Genetic structure within plots was analysed using spatial autocorrelation analyses. No significant clustering of similar genotypes was detected in either species when redundant samples from the same genets were culled from the data sets. In contrast, strong clustering was detected in R. vesiculosus when all samples were analysed, but not in R. vinicolor. These results demonstrate that isolation by distance does not occur in either species at the intraplot sampling scale and that clonal propagation (vegetative growth) is significantly more prevalent in R. vesiculosus than in R. vinicolor. Significant genetic differentiation was detected between some of the plots and appeared greater in the more clonal species R. vesiculosus with ΦST values ranging from 0.010 to 0.078*** than in R. vinicolor with ΦST values ranging from −0.002 to 0.022** (*P < 0.05, **P < 0.01, ***P < 0.001). When tested against the null hypothesis of no relationship between individuals, parentage analysis detected seven likely parent/offspring pairs in R. vinicolor and four in R. vesiculosus (α = 0.001). Of these 11 possible parent/offspring pairs, only two R. vinicolor pairs were still supported as parent/offspring when tested against the alternative hypothesis of being full siblings (α = 0.05). In the latter two cases, parent and offspring were located at approximately 45 m and 28 m from each other. Challenges to parentage analysis in ectomycorrhizal fungi are discussed.
Genetic structure in a solitary rodent (Ctenomys talarum): implications for kinship and dispersal
Authors: CUTRERA A. P. , LACEY E. A. , BUSCH C.
Published: June 2005

The genetic structure of a population provides critical insights into patterns of kinship and dispersal. Although genetic evidence of kin structure has been obtained for multiple species of social vertebrates, this aspect of population biology has received considerably less attention among solitary taxa in which spatial and social relationships are unlikely to be influenced by kin selection. Nevertheless, significant kin structure may occur in solitary species, particularly if ecological or life history traits limit individual vagility. To explore relationships between genetic structure, kinship, and dispersal in a solitary vertebrate, we compared patterns of genetic variation in two demographically distinct populations of the talar tuco‐tuco (Ctenomys talarum), a solitary species of subterranean rodent from Buenos Aires Province, Argentina. Based on previous field studies of C. talarum at Mar de Cobo (MC) and Necochea (NC), we predicted that natal dispersal in these populations is male biased, with dispersal distances for males and females being greater at NC. Analyses of 12 microsatellite loci revealed that in both populations, kin structure was more apparent among females than among males. Between populations, kinship and genetic substructure were more pronounced at MC. Thus, our findings were consistent with predicted patterns of dispersal for these animals. Collectively, these results indicate that populations of this solitary species are characterized by significant kin structure, suggesting that, even in the absence of sociality and kin selection, the spatial distributions and movements of individuals may significantly impact patterns of genetic diversity among conspecifics.
Detecting the number of clusters of individuals using the software structure: a simulation study
Authors: EVANNO G. , REGNAUT S. , GOUDET J.
Published: June 2005

The identification of genetically homogeneous groups of individuals is a long standing issue in population genetics. A recent Bayesian algorithm implemented in the software structure allows the identification of such groups. However, the ability of this algorithm to detect the true number of clusters (K) in a sample of individuals when patterns of dispersal among populations are not homogeneous has not been tested. The goal of this study is to carry out such tests, using various dispersal scenarios from data generated with an individual‐based model. We found that in most cases the estimated ‘log probability of data’ does not provide a correct estimation of the number of clusters, K. However, using an ad hoc statistic ΔK based on the rate of change in the log probability of data between successive K values, we found that structure accurately detects the uppermost hierarchical level of structure for the scenarios we tested. As might be expected, the results are sensitive to the type of genetic marker used (AFLP vs. microsatellite), the number of loci scored, the number of populations sampled, and the number of individuals typed in each sample.
High diversity of oilseed rape pollen clouds over an agro‐ecosystem indicates long‐distance dispersal
Authors: DEVAUX C. , LAVIGNE C. , FALENTIN‐GUYOMARC'H H. , VAUTRIN S. , LECOMTE J. , KLEIN E. K.
Published: June 2005

Estimating the frequency of long‐distance pollination is important in cultivated species, particularly to assess the risk of gene transfer following the release of genetically modified crops. For this purpose, we estimated the diversity and origin of fertilizing pollen in a 10 × 10 km French oilseed rape production area. First, the cultivar grown in each field was identified through surveys to farmers and using microsatellite markers. Examination of the seed set in fields indicated high rates of seed contamination (8.7%) and pollination from other sources (5%). Then, male‐sterile plants were scattered over the study area and their seed genotyped using the same markers. Most pollination was local: 65% of the seeds had a compatible sire in the closest field, i.e. at 50 or 300 m depending on site, but the nearest compatible field was found more than 1000 m away for 13% of the seeds. To assess the diversity of fertilizing pollen, each seed was assigned to the nearest putative siring cultivar. The observed diversity of pollen was then compared to that predicted by simulations using three empirical dispersal models with increasing proportion of long‐distance pollination. The diversity was sensitive to the dispersal kernel used in the simulations, fatter‐tailed functions predicting higher diversities. The dispersal kernel that was more consistent with our data predicted more long‐distance dispersal than the exponential function.
Landscape genetics of the blotched tiger salamander (Ambystoma tigrinum melanostictum)
Authors: SPEAR STEPHEN F. , PETERSON CHARLES R. , MATOCQ MARJORIE D. , STORFER ANDREW
Published: June 2005

The field of landscape genetics has great potential to identify habitat features that influence population genetic structure. To identify landscape correlates of genetic differentiation in a quantitative fashion, we developed a novel approach using geographical information systems analysis. We present data on blotched tiger salamanders (Ambystoma tigrinum melanostictum) from 10 sites across the northern range of Yellowstone National Park in Montana and Wyoming, USA. We used eight microsatellite loci to analyse population genetic structure. We tested whether landscape variables, including topographical distance, elevation, wetland likelihood, cover type and number of river and stream crossings, were correlated with genetic subdivision (FST). We then compared five hypothetical dispersal routes with a straight‐line distance model using two approaches: (i) partial Mantel tests using Akaike's information criterion scores to evaluate model robustness and (ii) the BIOENV procedure, which uses a Spearman rank correlation to determine the combination of environmental variables that best fits the genetic data. Overall, gene flow appears highly restricted among sites, with a global FST of 0.24. While there is a significant isolation‐by‐distance pattern, incorporating landscape variables substantially improved the fit of the model (from an r2 of 0.3 to 0.8) explaining genetic differentiation. It appears that gene flow follows a straight‐line topographic route, with river crossings and open shrub habitat correlated with lower FST and thus, decreased differentiation, while distance and elevation difference appear to increase differentiation. This study demonstrates a general approach that can be used to determine the influence of landscape variables on population genetic structure.
Age, phylogeography and population structure of the microendemic banded spring snail,Mexipyrgus churinceanus
Authors: JOHNSON STEVEN G.
Published: June 2005

Recent theoretical and empirical studies of phylogeography and population structure indicate that many processes influence intraspecific evolutionary history. The present study represents the first examination of various forces influencing the spatial and temporal patterns of sequence variation in the freshwater Mexican banded spring snail,Mexipyrgus churinceanus. This snail occurs in one of the most critically endangered centres of freshwater endemism, the desert ecosystem of Cuatro Ciénegas. From cytochromebmtDNA sequence variation, there is strong evidence of long‐term isolation of three regions, suggesting that these regions represent evolutionarily distinct lineages. Molecular clock estimates of clade age indicate a time to most recent common ancestor of approximately 2.5 million years ago (Ma). The three regions differ considerably in the historical and demographic forces affecting population structure. The western populations have extremely low mtDNA diversity consistent with a severe bottleneck dating to 50 000 years before present (bp). The nearby Rio Mesquites drainage is characterized by fragmentation events, restricted gene flow with isolation by distance, and higher levels of mtDNA polymorphism. These patterns are consistent with the long‐term stability of this drainage along with habitat heterogeneity and brooding contributing to population isolation and restricted gene flow. Southeastern populations show evidence of range expansion and a strong influence of genetic drift. Migration rates between drainages indicate very little gene flow between drainages except for asymmetric migration from the Rio Mesquites into both western and southeastern drainages.
Half‐sib family structure of Fagus crenata saplings in an old‐growth beech–dwarf bamboo forest
Authors: ASUKA Y. , TOMARU N. , MUNEHARA Y. , TANI N. , TSUMURA Y. , YAMAMOTO S.
Published: June 2005

Half‐sib family structure of Fagus crenata saplings was examined in an old‐growth beech–dwarf bamboo (Sasa spp.) forest using microsatellite genotypes in parentage analysis to identify the half‐sib families in two 50 × 50 m plots: one with 36 adults, 641 saplings and no Sasa cover, the other with 21 adults, 61 saplings and Sasa cover. For large proportions of the saplings (44.6% and 75.4%, respectively) both of their parents were found within the same plot, indicating that pollination events frequently involved short‐range pollen dispersal, probably because of the high density of adults in the study population. Although almost all of the adults had half‐sib families, the number of offspring in the families was highly variable. In the plot with no Sasa cover, the variation in the number of offspring was significantly explained by the size of parents, i.e. the reproductive success is higher for large adults than for small adults. The half‐sibs were aggregately distributed around their parents and the distribution overlapped among different half‐sib families, which may be due to the limited seed dispersal and overlapping seed shadows of this species. As expected, there was weak genetic structure in the plot. By contrast, in the plot with Sasa cover, the half‐sibs were distributed sparsely with a low density, and the degree of genetic structure was very weak. The difference in the half‐sib family structure and genetic structure among saplings presumably reflects the difference in density that should be affected by regeneration dynamics associated with environmental conditions.
Invasion of Lepidium draba (Brassicaceae) in the western United States: distributions and origins of chloroplast DNA haplotypes
Authors: GASKIN JOHN F. , ZHANG DAO‐YUAN , BON MARIE‐CLAUDE
Published: June 2005

Advances in phylogeography are of great value for understanding the population structure and origins of invasive genotypes. Such insights provide constructive information for current or future biological control research efforts. In this study, we investigated a highly variable chloroplast DNA (cpDNA) marker for populations of the weed Lepidium draba (Brassicaceae) in its native Eurasian and invasive US ranges. We sequenced DNA from 684 individuals from Eurasia and the US and found 41 different haplotypes. Our comparative study between the native and invasive ranges showed a 33% reduction in allelic richness (A) and a 7% reduction in haplotype diversity (h) since introduction into the US. Most genetic variation in the native range was observed within geographical regions and populations, not between regions, and this result was similar for the invasive range. Assignment tests indicated the most likely origins of many invasive haplotypes. Some of these occurred in western Europe, supporting an expanded native range that had been proposed for the species. Exact locations were identified for a diverse set of invasive haplotypes which can be used in ongoing host‐specificity tests of potential biological control agents.
A mitogenic view on the evolutionary history of the Holarctic freshwater gadoid, burbot (Lota lota)
Authors: VAN HOUDT J. K. J. , DE CLEYN L. , PERRETTI A. , VOLCKAERT F. A. M.
Published: June 2005

Climatic oscillations during the Pleistocene epoch had a dramatic impact on the distribution of biota in the northern hemisphere. In order to trace glacial refugia and postglacial colonization routes on a global scale, we studied mitochondrial DNA sequence variation in a freshwater fish (burbot,Lota lota; Teleostei, Gadidae) with a circumpolar distribution. The subdivision of burbot in the subspeciesLota lota lota(Eurasia and Alaska) andLota lota maculosa(North America, south of the Great Slave Lake) was reflected in two distinct mitochondrial lineages (average genetic distance is 2.08%). Thelotaform was characterized by 30 closely related haplotypes and a large part of its range (from Central Europe to Beringia) was characterized by two widespread ancestral haplotypes, implying that transcontinental exchange/migration was possible for cold‐adapted freshwater taxa in recent evolutionary time. However, the derived mitochondrial variants observed in peripheral populations point to a recent separation from the core group and postglacial recolonization from distinct refugia. Beringia served as refuge from whereL. l. lotadispersed southward into North America after the last glacial maximum. Genetic variation in themaculosaform consisted of three mitochondrial clades, which were linked to at least three southern refugia in North America. Two mitochondrial clades east of the Continental Divide (Mississippian and Missourian clades) had a distinct geographical distribution in the southern refuge zones but intergraded in the previously glaciated area. The third clade (Pacific) was exclusively found west of the Continental Divide.
Parentage versus two‐generation analyses for estimating pollen‐mediated gene flow in plant populations
Authors: BURCZYK JAROSLAW , KORALEWSKI TOMASZ E.
Published: June 2005

Assessment of contemporary pollen‐mediated gene flow in plants is important for various aspects of plant population biology, genetic conservation and breeding. Here, through simulations we compare the two alternative approaches for measuring pollen‐mediated gene flow: (i) theneighborhoodmodel — a representative of parentage analyses, and (ii) the recently developedtwogeneranalysis of pollen pool structure. We investigate their properties in estimating the effective number of pollen parents (Nep) and the mean pollen dispersal distance (δ). We demonstrate that both methods provide very congruent estimates ofNepand δ, when the methods’ assumptions considering the shape of pollen dispersal curve and the mating system follow those used in data simulations, although theneighborhoodmodel exhibits generally lower variances of the estimates. The violations of the assumptions, especially increased selfing or long‐distance pollen dispersal, affect the two methods to a different degree; however, they are still capable to provide comparable estimates ofNep. Theneighborhoodmodel inherently allows to estimate both self‐fertilization and outcrossing due to the long‐distance pollen dispersal; however, thetwogenermethod is particularly sensitive to inflated selfing levels, which in turn may confound and suppress the effects of distant pollen movement. As a solution we demonstrate that in case oftwogenerit is possible to extract the fraction of intraclass correlation that results from outcrossing only, which seems to be very relevant for measuring pollen‐mediated gene flow. The two approaches differ in estimation precision and experimental efforts but they seem to be complementary depending on the main research focus and type of a population studied.
Genetic structure and environmental heterogeneity in the European hake (Merluccius merluccius)
Authors: CIMMARUTA R. , BONDANELLI P. , NASCETTI G.
Published: June 2005

This study aimed at assessing the genetic structure and the state of the stocks of the European hake (Merluccius merluccius). To this end, 15 samples were taken from the whole range of the species and analysed using allozymes. Since 11 samples were taken from the poorly studied Mediterranean Sea, the results obtained provided a complete picture of the hake's genetic structure and an initial insight into its relationships with environmental features. Atlantic and Mediterranean hake populations are separated by the Almeria‐Oran front. This area has been proved to be the boundary between Atlantic and Mediterranean stocks of many marine organisms, but some doubt exists concerning the efficaciousness of the local gyres as barriers to the gene flow. Our data have evidenced a latitudinal cline at loci Gapdh and Gpi‐2 within the Mediterranean Sea, with a further steep change across the Almeria‐Oran front. The genetic pattern showed a strong correlation with the values of the salinity both at the surface and at −320 m and of the salinity + temperature at the surface, suggesting a role for these parameters in maintaining the genetic differentiation among the two population groups through selective processes. Finally, the levels of genetic variability were found to be slightly lower in the depleted Atlantic stock than in the Mediterranean one.
Microsatellite analyses reveal fine‐scale genetic structure in grey mouse lemurs (Microcebus murinus)
Authors: FREDSTED T. , PERTOLDI C. , SCHIERUP M. H. , KAPPELER P. M.
Published: June 2005

Information on genetic structure can be used to complement direct inferences on social systems and behaviour. We studied the genetic structure of the solitary grey mouse lemur (Microcebus murinus), a small, nocturnal primate endemic to western Madagascar, with the aim of getting further insight on its breeding structure. Tissue samples from 167 grey mouse lemurs in an area covering 12.3 km2in Kirindy Forest were obtained from trapping. The capture data indicated a noncontinuous distribution of individuals in the study area. Using 10 microsatellite markers, significant genetic differentiation in the study area was demonstrated and dispersal was found to be significantly male biased. Furthermore, we observed an overall excess of homozygotes in the total population (FIT = 0.131), which we interpret as caused by fine‐scale structure with breeding occurring in small units. Evidence for a clumped distribution of identical homozygotes was found, supporting the notion that dispersal distance for breeding was shorter than that for foraging, i.e. the breeding neighbourhood size is smaller than the foraging neighbourhood size. In conclusion, we found a more complex population structure than what has been previously reported in studies performed on smaller spatial scales. The noncontinuous distribution of individuals and the effects of social variables on the genetic structure have implications for the interpretation of social organization and the planning of conservation activities that may apply to other solitary and endangered mammals as well.
Conservation implications of complex population structure: lessons from the loggerhead turtle (Caretta caretta)
Authors: BOWEN B. W. , BASS A. L. , SOARES L. , TOONEN R. J.
Published: June 2005

Complex population structure can result from either sex‐biased gene flow or population overlap during migrations. Loggerhead turtles (Caretta caretta) have both traits, providing an instructive case history for wildlife management. Based on surveys of maternally inherited mtDNA, pelagic post‐hatchlings show no population structure across the northern Atlantic (φST < 0.001, P = 0.919), subadults in coastal habitat show low structure among locations (φST = 0.01, P < 0.005), and nesting colonies along the southeastern coast of the United States have strong structure (φST = 0.42, P < 0.001). Thus the level of population structure increases through progressive life history stages. In contrast, a survey of biparentally inherited microsatellite DNA shows no significant population structure: RST < 0.001; FST = 0.002 (P > 0.05) across the same nesting colonies. These results indicate that loggerhead females home faithfully to their natal nesting colony, but males provide an avenue of gene flow between regional nesting colonies, probably via opportunistic mating in migratory corridors. As a result, all breeding populations in the southeastern United States have similar levels of microsatellite diversity (HE = 0.70–0.89), whereas mtDNA haplotype diversity varies dramatically (h = 0.00–0.66). Under a conventional interpretation of the nuclear DNA data, the entire southeastern United States would be regarded as a single management unit, yet the mtDNA data indicate multiple isolated populations. This complex population structure mandates a different management strategy at each life stage. Perturbations to pelagic juveniles will have a diffuse impact on Atlantic nesting colonies, mortality of subadults will have a more focused impact on nearby breeding populations, and disturbances to adults will have pinpoint impact on corresponding breeding populations. These findings demonstrate that surveys of multiple life stages are desirable to resolve management units in migratory marine species.
Invasion from the cold past: extensive introgression of mountain hare (Lepus timidus) mitochondrial DNA into three other hare species in northern Iberia
Authors: MELO‐FERREIRA J. , BOURSOT P. , SUCHENTRUNK F. , FERRAND N. , ALVES P. C.
Published: June 2005

Mitochondrial DNA introgression fromLepus timidusintoLepus granatensisandLepus europaeuswas recently reported in Iberia, althoughL. timiduspresumably retreated from this region at the end of the last ice age. Here we assess the extent of this ancient mtDNA introgression by RFLP analysis of 695 specimens representing the three hare species present in Iberia. The introgressedL. timiduslineage was found in 23 of the 37 populations sampled. It is almost fixed inL. europaeusacross its Iberian range in the Pyrenean foothills, and inL. granatensis, which occupies the rest of the peninsula, it is predominant in the north and gradually disappears further south. We also found it inLepus castroviejoi, a species endemic to Cantabria. Multiple hybridizations and, potentially, a selective advantage for theL. timiduslineage can explain the remarkable taxonomic and geographical range of this mitochondrial introgression.
Phylogeography of two European newt species — discordance between mtDNA and morphology
Authors: BABIK W. , BRANICKI W. , CRNOBRNJA‐ISAILOVIĆ J. , COGĂLNICEANU D. , SAS I. , OLGUN K. , POYARKOV N. A. , GARCIA‐PARÍS M. , ARNTZEN J. W.
Published: June 2005

The newts Triturus vulgaris and Triturus montandoni are sister species that exhibit contrasting levels of intraspecific morphological variation. Triturus vulgaris has a broad Eurasiatic distribution encompassing both formerly glaciated and unglaciated areas and shows substantial morphological differentiation in the southern part of its range, while T. montandoni, confined to the Carpathians, is morphologically uniform. We analysed sequence variation of two mtDNA fragments of the total length of c. 1850 bp in 285 individuals of both species collected from 103 localities. Phylogenetic analysis of 200 unique haplotypes defined 12 major clades, their age estimated at c. 4.5–1.0 million years (Myr). Most of the older clades were found in the southern part of the range, and also in central Europe, mainly in Romania. The distribution of mtDNA clades points to the existence of several glacial refugia, located in the Caucasus region, Anatolia, the Balkan Peninsula, Italy, and more to the north in central Europe. The concordance between mtDNA based phylogeny and the distribution of T. vulgaris subspecies was weak. Triturus montandoni haplotypes did not form a monophyletic group. Instead they were found in six clades, in five of them mixed with T. vulgaris haplotypes, most likely as a result of past or ongoing hybridization and multiple introgression of mtDNA from T. vulgaris to T. montandoni. Patterns of sequence variation within clades suggested long‐term demographic stability in the southern groups, moderate and relatively old demographic growth in the populations inhabiting central Europe, and high growth in some of the groups that colonized northern parts of Europe after the last glacial maximum.
Coincidence of atopy profile in terms of monosensitization and polysensitization in children and their parents
Authors: Kang H. , Yu J. , Yoo Y. , Kim D. K. , Koh Y. Y.
Published: June 2005

Background:  Results from epidemiologic studies have shown that childhood atopy is probably a hereditary disorder, because the offspring of affected parents have a higher risk of developing atopy. Among the atopic population, some subjects are sensitized to only one class of allergens (monosensitized), while other subjects are sensitized to more than one class of allergens (polysensitized). The aim of this study was to investigate whether atopy profile (monosensitization/polysensitization) in children is linked to the same conditions in their parents.

Methods:  We evaluated sensitization to five classes of aeroallergens (house dust mites, animal danders, pollens, molds, and cockroach) by skin prick testing in a group of 494 children with suspicious allergic symptoms and in their parents.

Results:  The frequency of parental atopy was highest (51.6%) in polysensitized children (n = 189), intermediate (37.1%) in monosensitized children (n = 178), and was lowest (22.4%) in nonsensitized children (n = 127). The proportion of polysensitized subjects among atopic parents was significantly higher for polysensitized children (45.6%) than for monosensitized children (31.1%). Polysensitized children were found to more frequently have one or both parents polysensitized (32.3%, 7.4%) than monosensitized children (18.5%, 2.2%) with odds ratios of 2.09 (95% CI: 1.29–3.40) and 3.48 (1.12–10.78), respectively, whereas the likelihood of having one or two monosensitized parents was not increased for polysensitized children.

Conclusion:  Our data suggest a familial coincidence of atopy profile in terms of monosensitization and polysensitization, although the relative importance of genetic or environmental influence should be studied further.
Utility of the ratio of food‐specific IgE/total IgE in predicting symptomatic food allergy in children
Authors: Mehl A. , Verstege A. , Staden U. , Kulig M. , Nocon M. , Beyer K. , Niggemann B.
Published: June 2005

Background:  Double‐blind, placebo‐controlled food challenges are time‐consuming, expensive and not without risk to patients. Therefore, an in vitro test that could accurately diagnose food allergy would be of great value.

Objective:  To evaluate the utility of the ratio of specific immunoglobulin E (IgE)/total IgE compared with specific IgE (sIgE) alone in predicting symptomatic food allergy.

Methods:  We retrospectively analysed 992 controlled oral food challenges performed in 501 children (median age 13 months). The ratio of sIgE/total IgE was calculated and tested for correlation with the outcome of food challenges. Receiver operator characteristics (ROC)‐curves were performed; predicted probabilities and predictive decision points were calculated.

Results:  A significant correlation was found between the ratio and the outcome of food challenges for cow's milk (CM), hen's egg (HE), and wheat, but not for soy. The ROC and predicted probability curves as well as sensitivity and specificity of the decision points of the ratio were similar to those of sIgE levels for CM, HE and wheat.

Conclusion:  In view of the greater effort needed to determine the ratio, without benefit compared with the sIgE alone, the calculation of the ratio of sIgE/total IgE for diagnosing symptomatic food allergy offers no advantage for CM, HE, wheat or soy. For the majority of cases controlled oral food challenges still remain the method of choice.
Mutations in the high‐affinity IgE receptor β‐chain are not associated with nonresponder status
Authors: Küster H. , Von Manstein S. , Ruocchio‐Wiglinghaus S. , Von Brunn A. , Reinhardt D.
Published: June 2005

Background:  Basophils of some individuals do not release histamine upon activation of their high‐affinity immunoglobulin E (IgE) receptor (FcRI), but do so if this receptor is circumvented for cell activation. This so‐called nonresponder phenomenon is clinically relevant, because in various studies atopy was less frequent or absent in nonresponder individuals. So far, it is unknown if this phenomenon is acquired during adulthood or exists from birth on.

Methods:  Histamine release was determined from isolated leucocytes stimulated with anti‐IgE or calciumionophor. Also, random primed cDNA was synthesized and the open reading frame (ORF) of the FcRI β‐subunit amplified and sequenced.

Results:  In the first part of our study, we examined the role of atopic status, type of atopy, and age in a random population of 95 children of whom we found 22% to be nonresponder. None of these parameters correlated with the nonresponder status. Except for food allergy, no specific type of atopy correlated with histamine release. The mechanism underlying the nonresponder phenomenon is assumed to occur early in the signalling cascade. We hypothesized that mutations in the FcRI β‐chain may be associated with the nonresponder status, and in the second part of our study sequenced the β‐subunit in 20 responders and 20 nonresponders. Two conservative and two nonconservative heterozygous one base mutations (Thr179Thr, Asp216Asp, Ile147Leu and Glu237Gly) were found in two nonresponders and one responder. Three of these mutations have not been described so far.

Conclusion:  The nonresponder phenomenon is present from birth on and genetically determined. In our population, it was not associated with age or the presence of atopy, and appeared not to be caused by mutations in the FcRI β‐chain.
Gene expression and regulation of transcription factor activator protein‐2 alpha in human mast cells
Authors: Welker P. , Wanner R. , Zuberbier T. , Groneberg D. A. , Henz B. M.
Published: June 2005

Background:  The transcription factor activator protein (AP)‐2 regulates cell‐type specific gene expression during development and differentiation, but its role in mast cell development has so far not been explored.

Methods:  Gene expression and regulation of AP2 was assessed in normal skin, diseases with increased mast cell numbers, and in vitro models of mast cell differentiation.

Results:  AP‐2α‐protein was not detectable in normal skin but in mastocytoma lesional mast cells. AP‐2α‐mRNA and ‐protein were also detected in leukemic mast cells (HMC‐1), in the adherent fraction of peripheral blood (PBMC) and umbilical cord blood mononuclear cells (CBMC), and AP‐2α‐mRNA at low levels in isolated‐purified mast cells. During culture with fibroblast supernatants or SCF, AP‐2α‐mRNA was de novo expressed in KU812‐cells, maintained at about the same level in PBMC and CBMC, and upregulated in HMC‐1‐cells. On extended culture, a down‐regulation was noted at mRNA and/or protein levels. In contrast, tryptase expression increased in all cells throughout culture, as did c‐Kit in normal cells, whereas in both leukemic cell lines, c‐Kit was maintained unchanged at about the same level.

Conclusions:  These findings suggest a continuous activation of AP‐2α in mastocytomas and mast cell leukemia and its transient upregulation during c‐Kit dependent early steps of normal mast cell differentiation.
Dog factor differences in Can f 1 allergen production
Authors: Ramadour M. , Guetat M. , Guetat J. , El Biaze M. , Magnan A. , Vervloet D.
Published: June 2005

Background:  The clinical importance of dog allergy is well known, but it is unknown if all types of dogs represent the same risk for allergic patients.

The purpose of this work was to evaluate among 288 healthy dogs if the levels of Can f 1 on fur vary between breeds (German Shepherd, Pyrenean Shepherd, Poodle, Cocker spaniel, Spaniel, Griffon, Labrador retriever and Yorkshire terrier), gender, hormonal status, hair length, and according to the presence of seborrhea.

Methods:  Each dog was shaved in a limited area and Can f 1 concentrations were measured in μg/g fur by ELISA. The results (geometric mean values and 95% confidence intervals) were analyzed using analysis of variance and with nonparametric tests.

Results:  A wide variability in Can f 1 levels was found between dog breeds, from Labradors [1.99 (0.03–129.91)] to Yorkshires [16.72 (3.67–76.16)] and Poodles [17.04 (2.79–103.94)] but only the Labrador levels were significantly different from each other breed. Males produced more Can f 1 than females, 11.75 (1.27–108.40) vs 8.89 (0.91–86.39). No difference was found according to hair length or hormonal status. The seborrheic status highly (P = 0.0019) influenced the presence of Can f 1 on hair: 16.66 (1.59–173.96) vs 9.40 (1.03–85.70).

Conclusion:  Breeds (Labrador retriever), sex and seborrhea seem to influence the levels of Can f 1 on fur.
A framework for measuring costs to society of IgE‐mediated food allergy
Authors: Miles S. , Fordham R. , Mills C. , Valovirta E. , Mugford M.
Published: June 2005

Both immunoglobulin E (IgE)‐mediated food allergy and food intolerance can lead to many changes in personal behaviour and health care resource use which have important economic consequences. These costs will impact directly, indirectly and intangibly on both individuals and society in general. It is important to measure the cost of illness (COI) of food allergy as a first step in developing and evaluating measures to reduce and control the burden of illness. This paper outlines a framework for assessing COI of food allergy from different viewpoints. It offers a structure for identifying the different cost impacts on allergic and nonallergic consumers, food producers and society as a whole, and for scoping, measurement and valuation of relevant costs. Within this structure, the existing literature is reviewed. This review illustrates the lack of information and clear methodology for assessing costs of food allergy. The paper concludes that there is a need for a more structured research programme to generate data essential for future evaluations of procedures and technologies for the diagnosis, treatment and management of food allergy.
Allergic bronchopulmonary aspergillosis
Authors: Tillie‐Leblond I. , Tonnel A.‐B.
Published: June 2005

Allergic bronchopulmonary aspergillosis (ABPA) occurs in nonimmunocompromised patients and belongs to the hypersensitivity disorders induced by Aspergillus. Genetic factors and activation of bronchial epithelial cells in asthma or cystic fibrosis are responsible for the development of a CD4+Th2 lymphocyte activation and IgE, IgG and IgA‐AF antibodies production. The diagnosis of ABPA is based on the presence of a combination of clinical, biological and radiological criteria. The severity of the disease is related to corticosteroid‐dependant asthma or/and diffuse bronchiectasis with fibrosis. The treatment is based on oral corticosteroids for 6–8 weeks at acute phase or exacerbation and itraconazole is now recommended and validated at a dose of 200 mg/day for a duration of 16 weeks.
The Macro Content of PRSPs: Assessing the Need for a More Flexible Macroeconomic Policy Framework
Authors: Gottschalk Ricardo
Published: June 2005

This article analyses the content of 15 Poverty Reduction Strategy Papers from a growth and poverty reduction perspective. Contrary to new trends in developed and middle‐income countries, their policy frameworks lack the necessary flexibility to deal with external shocks and address macroeconomic volatility appropriately. Their fiscal and monetary policies are too narrowly focused on fiscal balance and price stability and consequently pay too little attention to economic fluctuations arising from external shocks, which have major effects on poverty and growth. To address these issues, the article proposes a set of policy measures, including avoidance of excessively tight inflation and fiscal targets (with provisions for fluctuations in commodity prices), more room for countercyclical policy and the adoption of permanent safety nets.
The PRSP Approach and the Illusion of Improved Aid Effectiveness: Lessons from Bolivia, Honduras and Nicaragua
Authors: Dijkstra Geske
Published: June 2005

Since 1999, poor countries that want to qualify for concessionary IMF loans and debt relief must elaborate and implement Poverty Reduction Strategy Papers. Donors claim that the PRSP approach will increase aid effectiveness since PRSPs will enhance broad country ownership and lead to better ‘partnership’ with donors, implying more donor co‐ordination under government leadership. By examining the experiences of Bolivia, Honduras and Nicaragua, this article finds that the results are disappointing. The article also shows that, by emphasising rational planning and ignoring politics, the PRSP approach has unintended and sometimes harmful consequences. This leads to recommendations for changes of the approach.