Search

Climate-induced range shifts result in the movement of a sample of genotypes from source populations to new regions. The phenotypic consequences of those shifts depend upon the sample characteristics of the dispersive genotypes, which may act to either constrain or promote phenotypic divergence, and the degree to which plasticity influences the genotype-environment interaction. We sampled populations of the damselfly Erythromma viridulum from northern Europe to quantify the phenotypic (latitude-body size relationship based on seven morphological traits) and genetic (variation at microsatellite loci) patterns that occur during a range expansion itself. We find a weak spatial genetic structure that is indicative of high gene flow during a rapid range expansion. Despite the potentially homogenizing effect of high gene flow, however, there is extensive phenotypic variation among samples along the invasion route that manifests as a strong, positive correlation between latitude and body size consistent with Bergmann's rule. This positive correlation cannot be explained by variation in the length of larval development (voltinism). While the adaptive significance of latitudinal variation in body size remains obscure, geographical patterns in body size in odonates are apparently underpinned by phenotypic plasticity and this permits a response to one or more environmental correlates of latitude during a range expansion., (© 2013 John Wiley & Sons Ltd.)

Movement is an important life history trait that can have an impact on local adaptation, and other evolutionary phenomena. We used a combination of nestbox survey data and genetic techniques (genotyping at 10 microsatellite loci) to quantify patterns of movement in common dormice Muscardinus avellanarius at two distinct sites in the UK: 1) Bontuchel (a natural population) and 2) Wych (captive-bred individuals that were reintroduced to this site), over three consecutive years (2006-2008). Both methods revealed a consistent pattern of sex-biased movement (movements by adult males and females) in both populations that allowed isolation-by-distance genetic structure to develop within 1 km. The similarity of data from captive-bred and natural individuals indicated that ex situ programing has not significantly altered the natural movement behavior of common dormice; consequently, the two populations could be managed with the same conservation strategies. We also found that the reintroduced dormice in Wych maintained relatively high levels of genetic diversity. This first report of movement patterns in reintroduced and natural populations of M. avellanarius combining genetic and field-survey data highlights the role of genetic studies in the investigation of ecological behaviour and for conservation management.

Effective population size (Ne) determines the rate of genetic drift and the relative influence of selection over random genetic changes. While free-living protist populations characteristically consist of huge numbers of cells (N), the absence of any estimates of contemporary Ne raises the question whether protist effective population sizes are comparably large. Using microsatellite genotype data of strains derived from revived cysts of the marine dinoflagellate Pentapharsodinium dalei from sections of a sediment record that spanned some 100 years, we present the first estimates of contemporary Ne for a local population in a free-living protist. The estimates of Ne are relatively small, of the order of a few 100 individuals, and thus are similar in magnitude to values of Ne reported for multicellular animals: the implications are that Ne of P. dalei is of many orders of magnitude lower than the number of cells present (Ne/N ∼ 10(-12)) and that stochastic genetic processes may be more prevalent in protist populations than previously anticipated.

We use strains recently collected from the field to establish cultures; then, through laboratory studies we investigate how among strain variation in protozoan ingestion and growth rates influences population dynamics and intraspecific competition. We focused on the impact of changing temperature because of its well-established effects on protozoan rates and its ecological relevance, from daily fluctuations to climate change. We show, first, that there is considerable inter-strain variability in thermal sensitivity of maximum growth rate, revealing distinct differences among multiple strains of our model species Oxyrrhis marina. We then intensively examined two representative strains that exhibit distinctly different thermal responses and parameterised the influence of temperature on their functional and numerical responses. Finally, we assessed how these responses alter predator-prey population dynamics. We do this first considering a standard approach, which assumes that functional and numerical responses are directly coupled, and then compare these results with a novel framework that incorporates both functional and numerical responses in a fully parameterised model. We conclude that: (i) including functional diversity of protozoa at the sub-species level will alter model predictions and (ii) including directly measured, independent functional and numerical responses in a model can provide a more realistic account of predator-prey dynamics.

The mechanisms that underpin the varied spatial genetic structures exhibited by free-living marine microorganisms remain controversial, with most studies emphasizing a high dispersal capability that should redistribute genetic diversity in contrast to most macroorganisms whose populations often retain a genetic signature of demographic response to historic climate fluctuations. We quantified the European phylogeographic structure of the marine flagellate Oxyrrhis marina and found a marked difference in spatial genetic structure, population demography, and genetic diversity between the northwest Atlantic and Mediterranean Sea that reflects the persistent separation of these regions as well as context-dependent population responses to contrasting environments. We found similar geographic variation in the level of genetic diversity in the sister species Oxyrrhis maritima. Because the capacity for wide dispersal is not always realized, historic genetic footprints of range expansion and contraction persist in contemporary populations of marine microbes, as they do in larger species. Indeed, the well-described genetic effects of climatic variation on macroorganisms provide clear, testable hypotheses about the processes that drive genetic divergence in marine microbes and thus about the response to future environmental change.

Repeated cycles of glaciation have had major impacts on the distribution of genetic diversity of the Antarctic marine fauna. During glacial periods, ice cover limited the amount of benthic habitat on the continental shelf. Conversely, more habitat and possibly altered seaways were available during interglacials when the ice receded and the sea level was higher. We used microsatellites and partial sequences of the mitochondrial cytochrome oxidase 1 gene to examine genetic structure in the direct-developing, endemic Southern Ocean octopod Pareledone turqueti sampled from a broad range of areas that circumvent Antarctica. We find that, unusually for a species with poor dispersal potential, P. turqueti has a circumpolar distribution and is also found off the islands of South Georgia and Shag Rocks. The overriding pattern of spatial genetic structure can be explained by hydrographic (with ocean currents both facilitating and hindering gene flow) and bathymetric features. The Antarctic Peninsula region displays a complex population structure, consistent with its varied topographic and oceanographic influences. Genetic similarities between the Ross and Weddell Seas, however, are interpreted as a persistent historic genetic signature of connectivity during the hypothesized Pleistocene West Antarctic Ice Sheet collapses. A calibrated molecular clock indicates two major lineages within P. turqueti, a continental lineage and a sub-Antarctic lineage, that diverged in the mid-Pliocene with no subsequent gene flow. Both lineages survived subsequent major glacial cycles. Our data are indicative of potential refugia at Shag Rocks and South Georgia and also around the Antarctic continent within the Ross Sea, Weddell Sea and off Adélie Land. The mean age of mtDNA diversity within these main continental lineages coincides with Pleistocene glacial cycles., (© 2012 Blackwell Publishing Ltd.)

Boldness, a measure of an individual's propensity for taking risks, is an important determinant of fitness but is not necessarily a fixed trait. Dependent upon an individual's state, and given certain contexts or challenges, individuals may be able to alter their inclination to be bold or shy in response. Furthermore, the degree to which individuals can modulate their behaviour has been linked with physiological responses to stress. Here we attempted to determine whether bold and shy rainbow trout, Oncorhynchus mykiss, can exhibit behavioural plasticity in response to changes in state (nutritional availability) and context (predation threat). Individual trout were initially assessed for boldness using a standard novel object paradigm; subsequently, each day for one week fish experienced either predictable, unpredictable, or no simulated predator threat in combination with a high (2% body weight) or low (0.15%) food ration, before being reassessed for boldness. Bold trout were generally more plastic, altering levels of neophobia and activity relevant to the challenge, whereas shy trout were more fixed and remained shy. Increased predation risk generally resulted in an increase in the expression of three candidate genes linked to boldness, appetite regulation and physiological stress responses - ependymin, corticotrophin releasing factor and GABA(A) - but did not produce a significant increase in plasma cortisol. The results suggest a divergence in the ability of bold and shy trout to alter their behavioural profiles in response to internal and exogenous factors, and have important implications for our understanding of the maintenance of different behavioural phenotypes in natural populations., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Increased education of consumers can be an effective tool for conservation of commercially harvested marine species when product labeling is accurate and allows an informed choice. However, generic labeling (e.g., as white fish or surimi) and mislabeling of seafood prevents this and may erode consumer confidence in seafood product labels in general. We used DNA barcoding to identify the species composition of two types of convenience seafood (i.e., products processed for ease of consumption): fish fingers (long pieces of fish covered with bread crumbs or batter, n = 241) and seafood sticks (long pieces of cooked fish, n = 30). In products labeled as either white fish or surimi, four teleost species were present. Less than 1.5% of fish fingers with species-specific information were mislabeled. Results of other studies show substantially more mislabeling (e.g., >25%) of teleost products, which likely reflects the lower economic gains associated with mislabeling of convenience seafood compared with whole fillets. In addition to species identification, seafood product labels should be required to contain information about, for example, harvesting practices, and our data indicate that consumers can have reasonable confidence in the accuracy of the labels of convenience seafood and thus select brands on the basis of information about current fisheries practice., (©2012 Society for Conservation Biology.)

Many species, particularly insects, pass through a series of distinct phases during their life history, with the developmental timing directed towards appropriate resources. Any factor that creates variation in developmental timing may partition a population into discrete populations-or 'cohorts'. Where there is continued failure to recruit outside the natal cohort then alternate cohorts will have their own internal dynamics, eventually leading to independent demographic and evolutionary trajectories. By contrast, continued variation in development rates within a cohort-cohort splitting-may homogenise otherwise independent demographic units. Using a panel of 14 microsatellite loci, we quantify the genetic signature of apparent demographic isolation between coexisting, but alternate, semivoltine cohorts of the damselfly Coenagrion mercuriale at locations that span its distribution in the UK. We find consistently low levels of genetic divergence between sympatric cohorts of C. mercuriale, indicative of developmental plasticity during the larval stage (unregulated development) whereby some individuals complete their development outside the predominant 2-year (semivoltine) period. Thus, individuals that alter their developmental rate successfully recruit to a different cohort. Despite maintaining contrasting population sizes, gene flow between alternate cohorts broadly is sufficient to place them on a similar evolutionary trajectory and also buffers against loss of genetic diversity. Such flexible larval development permits a response to local conditions and may facilitate response to environmental change.

Quantitative descriptions of population genetic structure allows the delineation of population units and is therefore of primary importance in population management and wildlife conservation. Yet, predicting factors that influence the gene flow patterns in populations particularly at landscape scales remains a major challenge in evolutionary biology. Here we report a population genetic study of the common dormouse, Muscardinus avellanarius, a species that is seriously threatened due to anthropogenic factors, in two regions, Bontuchel (Denbighshire) and Afonwen (Gwynedd), both in Wales, UK. Ten microsatellite loci were used to characterize patterns of genetic diversity of M. avellanarius within both regions. While the population differentiation between both regions is apparent through geographical scale separating them, by using Bayesian clustering analyses, we identified the occurrence of genetic division among populations of M. avellanarius in Bontuchel region, but no significant evidence of differentiation in Afonwen. We found a strong significant isolation-by-distance (IBD) pattern at a fine-scale (less than 1 km) within continuous habitat and between habitat patches in both regions. Overall, analyses suggest that small-scale dispersal associated with the social structure and dispersal tendencies of this species is reflected in the genetic structure of populations. These findings then provide useful baseline data for supporting local management strategies.

Background: The heterotrophic dinoflagellate Oxyrrhis marina is increasingly studied in experimental, ecological and evolutionary contexts. Its basal phylogenetic position within the dinoflagellates make O. marina useful for understanding the origin of numerous unusual features of the dinoflagellate lineage; its broad distribution has lent O. marina to the study of protist biogeography; and nutritive flexibility and eurytopy have made it a common lab rat for the investigation of physiological responses of marine heterotrophic flagellates. Nevertheless, genome-scale resources for O. marina are scarce. Here we present a 454-based transcriptome survey for this organism. In addition, we assess sequence read abundance, as a proxy for gene expression, in response to salinity, an environmental factor potentially important in determining O. marina spatial distributions., Results: Sequencing generated ~57 Mbp of data which assembled into 7, 398 contigs. Approximately 24% of contigs were nominally identified by BLAST. A further clustering of contigs (at ≥ 90% identity) revealed 164 transcript variant clusters, the largest of which (Phosphoribosylaminoimidazole-succinocarboxamide synthase) was composed of 28 variants displaying predominately synonymous variation. In a genomic context, a sample of 5 different genes were demonstrated to occur as tandem repeats, separated by short (~200-340 bp) inter-genic regions. For HSP90 several intergenic variants were detected suggesting a potentially complex genomic arrangement. In response to salinity, analysis of 454 read abundance highlighted 9 and 20 genes over or under expressed at 50 PSU, respectively. However, 454 read abundance and subsequent qPCR validation did not correlate well - suggesting that measures of gene expression via ad hoc analysis of sequence read abundance require careful interpretation., Conclusion: Here we indicate that tandem gene arrangements and the occurrence of multiple transcribed gene variants are common and indicate potentially complex genomic arrangements in O. marina. Comparison of the reported data set with existing O. marina and other dinoflagellates ESTs indicates little sequence overlap likely as a result of the relatively limited extent of genome scale sequence data currently available for the dinoflagellates. This is one of the first 454-based transcriptome surveys of an ancestral dinoflagellate taxon and will undoubtedly prove useful for future comparative studies aimed at reconstructing the origin of novel features of the dinoflagellates.

Multiplex PCR assays for the coamplification of microsatellite loci allow rapid and cost-effective genetic analyses and the production of efficient screening protocols for international breeding programs. We constructed a partial genomic library enriched for di-nucleotide repeats and characterized 14 new microsatellite loci for the Komodo monitor (or Komodo dragon, Varanus komodoensis). Using these novel microsatellites and four previously described loci, we developed multiplex PCR assays that may be loaded on a genetic analyser in three separate panels. We tested the novel set of microsatellites for polymorphism using 69 individuals from three island populations and evaluated the resolving power of the entire panel of 18 loci by conducting (i) a preliminary assignment test to determine population(s) of origin and (ii) a parentage analysis for 43 captive Komodo monitors. This panel of polymorphic loci proved useful for both purposes and thus can be exploited for fine-scale population genetic analyses and as part of international captive breeding programs directed at maintaining genetically viable ex situ populations and reintroductions., (© 2011 Blackwell Publishing Ltd.)

Bold, risk-taking animals have previously been putatively linked with a proactive stress coping style whereas it is suggested shyer, risk-averse animals exhibit a reactive coping style. The aim of this study was to investigate whether differences in the expression of bold-type behaviour were evident within and between two lines of rainbow trout, Oncorhynchus mykiss, selectively bred for a low (LR) or high (HR) endocrine response to stress, and to link boldness and stress responsiveness with the expression of related candidate genes. Boldness was determined in individual fish over two trials by measuring the latency to approach a novel object. Differences in plasma cortisol concentrations and the expression of eight novel candidate genes previously identified as being linked with divergent behaviours or stress were determined. Bold and shy individuals, approaching the object within 180 s or not approaching within 300 s respectively, were evident within each line, and this was linked with activity levels in the HR line. Post-stress plasma cortisol concentrations were significantly greater in the HR line compared with the LR line, and six of the eight tested genes were upregulated in the brains of LR fish compared with HR fish. However, no direct relationship between boldness and either stress responsiveness or gene expression was found, although clear differences in stress physiology and, for the first time, gene expression could be identified between the lines. This lack of correlation between physiological and molecular responses and behavioural variation within both lines highlights the complexity of the behavioural-physiological complex., (Copyright © 2010 Elsevier Inc. All rights reserved.)

Free-living marine protists are often assumed to be broadly distributed and genetically homogeneous on large spatial scales. However, an increasing application of highly polymorphic genetic markers (e.g., microsatellites) has provided evidence for high genetic diversity and population structuring on small spatial scales in many free-living protists. Here we characterise a panel of new microsatellite markers for the common marine flagellate Oxyrrhis marina. Nine microsatellite loci were used to assess genotypic diversity at two spatial scales by genotyping 200 isolates of O. marina from 6 broad geographic regions around Great Britain and Ireland; in one region, a single 2 km shore line was sampled intensively to assess fine-scale genetic diversity. Microsatellite loci resolved between 1-6 and 7-23 distinct alleles per region in the least and most variable loci respectively, with corresponding variation in expected heterozygosities (H(e)) of 0.00-0.30 and 0.81-0.93. Across the dataset, genotypic diversity was high with 183 genotypes detected from 200 isolates. Bayesian analysis of population structure supported two model populations. One population was distributed across all sampled regions; the other was confined to the intensively sampled shore, and thus two distinct populations co-occurred at this site. Whilst model-based analysis inferred a single UK-wide population, pairwise regional F(ST) values indicated weak to moderate population sub-division (0.01-0.12), but no clear correlation between spatial and genetic distance was evident. Data presented in this study highlight extensive genetic diversity for O. marina; however, it remains a substantial challenge to uncover the mechanisms that drive genetic diversity in free-living microorganisms.

1. Age-dependent increases in mortality have been documented in a variety of species of insect under laboratory conditions. However, while strong statistical evidence has been presented for senescence in vertebrate populations in the wild, we know little about the rate and shape of senescence in wild populations of insects. 2. Odonates (damselflies and dragonflies) provide excellent candidate species for evaluating demographic senescence as they are large enough to be marked individually and they are easily re-sighted without recapture. The prevailing opinion - based entirely on qualitative examination of the declines in log numbers alive with time since marking - is that odonates exhibit age-independent daily survivorship. 3. Here, we examine mark-recapture data on the Azure Damselfly Coenagrion puella over two consecutive seasons. For the first time, we evaluate and compare the fit of quantitative models that not only account for weather-dependent daily variation in daily re-sighting rates, but also age-dependent variation in daily survivorship. 4. Models with age-dependent declines in daily survivorship provide a more parsimonious explanation for the data than similar models without these age-dependent effects. In general, models in which mortality increases in an exponential (Gompertz) fashion explain the mark-recapture sequences more efficiently than a range of alternative models, including those in which mortality increases as a power function (Weibull) or reaches a plateau (logistic). These results are indicative of a general senescent decline in physiological functioning, which is particularly marked after 15 days as a mature adult. 5. Weather (temperature, sun and precipitation) and initial mite load influenced the probability of daily re-sighting. Weather and mite load also influenced daily survivorship, but their effects differed between seasons. 6. Overall, fitting models with age as an explicit covariate demonstrates that odonates do indeed senesce. This contradicts previously held assumptions that Odonata do not exhibit age-dependent survivorship in the wild.

Oxyrrhis marina is an important model in ecological studies of free-living protists. Despite this, O. marina has rarely been studied in the environment and no explicit distributional studies exist. Further, phylogenetic data for a small number of isolates indicate that O. marina constitutes two divergent lineages. Here, we quantify phylogenetic variation between 58 globally distributed O. marina isolates using 5.8S--internal transcribed spacer 1 and 2 rDNA (5.8S ITS) and cytochrome c oxidase I (COI) partial sequences. 5.8S ITS and COI phylogenies both partitioned O. marina into four clades, which formed two lineages; mean sequence identity for 5.8S ITS and COI respectively was approximately 40 and 90% between these two lineages. Sequence identities for 5.8S ITS/ COI between clades within lineages were 66.3/99.4% (lineage 1: clade 1 vs 2) and 42.3/99.1% (lineage 2: clade 3 vs 4). rDNA mutation rates in O. marina appear to be abnormally high and were not interpreted in a species delineation context. Based on variation in COI sequence and comparisons with other protists, we suggest that O. marina lineages may constitute two species. In a geographic context, evidence of spatial restriction but also extensive overlap between O. marina clades occurred. Further, clade abundances varied considerably: clades 1 and 2 (belonging to one lineage) were abundant and widespread; in contrast, clades 3 and 4 (belonging to the second lineage) were rare and spatially restricted (occurring only in the Mediterranean or in culture collection). There is need for further phylogenetic and taxonomic studies to assess species delineation in O. marina, and for the application of high resolution genetic markers to resolve processes driving genetic diversity in this important model organism., (Copyright 2009 Elsevier GmbH. All rights reserved.)

By a combination of detailed behavioral observations and molecular genetic approaches we have assessed development time, timing of first maturity, and the extent of genetic structure through the flying season in a wild population of the damselfly Coenagrion puella in England. This work provides the first estimate of development time (egg to mature adult) in the field based on individual damselflies. Development time was significantly longer for females than males. In contrast to reported laboratory studies, there was no difference in development times between different female color morphs. Development time ranged between 347 and 396 days and was negatively correlated with egg-laying date. As a result eggs laid early in one season reach adult maturity relatively late in the next; concurrently individuals developing from eggs laid late mature relatively early. We speculate that this pattern of development is a direct physiological response to seasonal environmental variation and results in reproductive synchrony within a population. Size, specifically hind wing length, declined with development time in males, but not in females. In one of the two years of the study there was evidence for weak clustering of related individuals during the reproductive season. This appeared to be the result of developmental synchronization within families: variance in timing of maturation was smaller in full-sib families than in half-sib families or randomly assigned unrelated groups.

Eighteen dinucleotide microsatellite loci were isolated from two octopus species, Pareledone turqueti and Pareledone charcoti, which are endemic to the Southern Ocean. Genetic diversity was assessed in samples of P. charcoti and P. turqueti from Elephant Island and Shag Rocks respectively. All except one locus (which has proved to be polymorphic in other species) were variable in the focal species and amplified between six and 30 and between four and 28 alleles for P. charcoti and P. turqueti respectively; mean expected heterozygosities varied between 0.38 and 0.95 (P. charcoti) and between 0.34 and 0.97 (P. turqueti), with significant (P < 0.05) departures from Hardy-Weinberg equilibrium at seven loci; three of these loci provided significant (P < 0.05) evidence for null alleles. Two pairs of loci isolated from P. turqueti demonstrated significant (P < 0.05) linkage disequilibrium. We are presently using these genetic markers to quantify spatial genetic structure in the genus Pareledone., (© 2009 Blackwell Publishing Ltd.)

To determine the pattern of spatial genetic structure in the endemic Southern Ocean octopus Adelieledone polymorpha, microsatellite loci were isolated from partial genomic libraries enriched for repetitive DNA motifs. Seven dinucleotide and two trinucleotide microsatellite loci were isolated successfully and levels of polymorphism were quantified in 34 individuals sampled from the Southern Ocean near South Georgia. No pairs of microsatellite loci were linked significantly; however, one locus deviated (P < 0.05) from Hardy-Weinberg equilibrium. Overall, the nine loci produced between five and 16 alleles, with observed and expected heterozygosities varying between 0.22 and 0.86 and between 0.21 and 0.94 respectively. This is the first description of microsatellite loci from an octopus endemic to the Southern Ocean, and these genetic markers are being used to quantify spatial structure within A. polymorpha., (© 2009 Blackwell Publishing Ltd.)

To assess the level and spatial pattern of genetic diversity of the common dormouse, Muscardinus avellanarius, we developed polymorphic microsatellite loci from partial genomic libraries enriched for microsatellite motifs. Ten dinucleotide polymorphic microsatellites were isolated and levels of genetic diversity were assessed in 139 individuals from Bontuchel, (Denbighshire, Wales). We observed high levels of heterozygosity (mean H(O)  = 0.792 ± 0.077; mean H(E)  = 0.730 ± 0.084) and a large number of alleles (N(a)  = 6-17). There was no evidence of deviations from Hardy-Weinberg conditions, or genotypic disequilibrium between any pairs of loci. This is the first description of microsatellite primers from a common dormouse and these loci are currently being used to quantify dormouse spatial genetic structure., (© 2009 Blackwell Publishing Ltd.)

Rhodnius prolixus is the main vector of Chagas disease in Venezuela, where it is found colonising rural housing consisting of unplastered adobe walls with palm and/or metal roofs. Vector control failure in Venezuela may be due to the invasion of houses by silvatic populations of R. prolixus found in palms. As part of a study to determine if domestic and silvatic populations of R. prolixus are isolated, thus clarifying the role of silvatic populations in maintaining house infestations, we constructed three partial genomic microsatellite libraries. A panel of ten dinucleotide polymorphic microsatellite markers was selected for genotyping. Allele numbers per locus ranged from three to twelve, with observed and expected heterozygosity ranging from 0.26 to 0.55 and 0.32 to 0.66. The microsatellite markers presented here will contribute to the control of Chagas disease in Venezuela and Colombia through the provision of population information that may allow the design of improved control strategies.

Seven dinucleotide and one trinucleotide polymorphic microsatellite loci were isolated from the mite Coccipolipus hippodamiae. This mite is an ectoparasite of coccinellid beetles (ladybirds), principally the European two-spot ladybird Adalia bipunctata, where it causes sterility in the female host. Levels of genetic diversity were assessed using 32 mites from Warsaw, Poland. We observed moderate variability, with the number of alleles per locus varying between 2 and 4, and observed and expected heterozygosities ranging from 0.031 to 0.267 and between 0.062 and 0.526, respectively. This is the first description of microsatellite loci from the genus Coccipolipus and these loci are currently being employed to answer fundamental questions about the epidemiology of C. hippodamiae infections on A. bipunctata., (© 2009 The Authors. Journal compilation © 2009 Blackwell Publishing Ltd.)

Historical datasets documenting changes to gene frequency clines are extremely rare but provide a powerful means of assessing the strength and relative roles of natural selection and gene flow. In 19th century Britain, blackening of the environment by the coal-fired manufacturing industry gave rise to a steep cline in the frequency of the black (carbonaria) morph of the peppered moth (Biston betularia) across northwest England and north Wales. The carbonaria morph has declined across the region following 1960s legislation to improve air quality, but the cline had not been comprehensively described since the early 1970s. We have quantified changes to the cline as of 2002, equivalent to an interval of 30 generations, and find that a cline still exists but that it is much shallower and shifted eastward. Joint estimation of the dominant fitness cost of carbonaria and dispersal parameters consistent with the observed cline change indicate that selection against carbonaria is very strong across the landscape (s approximately 0.2), and that dispersal is much greater than previously assumed. The high dispersal estimate is further supported by the weak pattern of genetic isolation by distance at microsatellite loci, and it implies that in addition to adult dispersal, wind-dispersed first instar larvae also contribute to lifetime dispersal. The historical perspective afforded by this study of cline reversal provides new insight into the factors contributing to gene frequency change in this species, and it serves to illustrate that, even under conditions of high dispersal and strong reverse selection acting against it, complete erosion of an established cline requires many generations.

We report the electrical characterization of single-walled carbon nanotubes (SWCNTs) trapped between two electrodes by dielectrophoresis (DEP). At high frequency, SWCNTs collected by DEP are expected to be of metallic type. Indeed current-voltage (I-V) measurements for devices made at 10 MHz show high values of conductivity and exhibit metallic behavior with linear and symmetric electrical features attributed to ohmic conduction. At low frequency, SWCNTs attracted by DEP are expected to be of semiconducting nature. Devices made at 10 kHz behave as semiconductors and demonstrate nonlinear and rectifying electrical characteristics with conductivities many orders of magnitude below the sample resulting from high-frequency immobilization of SWCNTs. Conducting atomic force microscopy (C-AFM) and current density calculation results are presented to reinforce results obtained by I-V measurements which clearly show type separation of SWCNTs after DEP experiments.

We report substantial improvement of the field emission properties from aligned carbon nanotubes grown on aligned carbon nanofibres by a two-stage plasma enhanced chemical vapour deposition (PECVD) process. The threshold field decreased from 15.0 to 3.6 V/microm after the secondary growth. The field enhancement factor increased from 240 to 1480. This technique allows for superior emission of electrons for carbon nanotube/nanofibre arrays grown directly on highly doped silicon for direct integration in large area displays.

1. Effective population sizes (N(e)) and migration rates (m) are critical evolutionary parameters that impact on population survival and determine the relative influence of selection and genetic drift. While the parameter m is well-studied in animal populations, N(e) remains challenging to measure and consequently is only rarely estimated, particularly in insect taxa. 2. We used demographic and genetic methods to estimate N(e) and m in a fragmented population of the endangered damselfly Coenagrion mercuriale to better understand the contrast between genetic and field estimates of these parameters and also to identify the spatial scale over which populations may become locally adapted. 3. We found a contrast between demographic- and genetic-based estimates of these parameters, with the former apparently providing overestimates of N(e), owing to substantial underestimation of the variance in reproductive success, and the latter overestimating m, because spatial genetic structure is weak. 4. The overall N(e) of sites within the population network at Beaulieu Heath, the largest C. mercuriale site in the UK, was estimated to vary between approximately 60 and 2700. 5. While N(e) was not correlated with either the total numbers of adults (N) or the area of habitat, this parameter was always less than N, because of substantial variance in reproductive success. The ratio N(e)/N varied between 0.006 and 0.42 and was generally larger in smaller populations, possibly representing some 'genetic compensation'. 6. From a simple genetic model and these data on N(e) and m, it seems that populations of C. mercuriale have the potential to respond to localized spatial variation in selection and this would need to be considered for future genetic management of this endangered species.

Poly(3hydroxybutyrate) (P(3HB))/Bioglass(®) composites incorporating multiwalled carbon nanotubes (MWCNTs) have been successfully prepared by the solvent casting technique. The microstructure, electrical properties and bioactivity of the composites were characterized using scanning electron microscopy, x-ray diffraction and current-voltage measurements. Different concentrations of MWCNTs were used to determine their effect on the electrical properties of the composites. MWCNTs and Bioglass(®) particles were found to be homogeneously dispersed throughout the P(3HB) matrix. The electrical resistance of the composite samples decreased on increasing the MWCNT concentration, as expected. An in vitro degradation study in simulated body fluid (SBF) was carried out on composite samples. The formation of hydroxyapatite on the surfaces of P(3HB)/Bioglass(®)/MWCNT composite films was confirmed after two months of immersion in SBF. This hydroxyapatite layer was not formed on the neat polymeric films and on composites containing MWCNTs only (without Bioglass(®)). It was found that the presence of MWCNTs did not hinder the bioactivity of the Bioglass(®) particles, as confirmed by SEM and XRD studies on composite samples.

Genetic and demographic estimates of dispersal are often thought to be inconsistent. In this study, we use the damselfly Coenagrion mercuriale (Odonata: Zygoptera) as a model to evaluate directly the relationship between estimates of dispersal rate measured during capture-mark-recapture fieldwork with those made from the spatial pattern of genetic markers in linear and two-dimensional habitats. We estimate the 'neighbourhood size' (Nb) - the product of the mean axial dispersal rate between parent and offspring and the population density - by a previously described technique, here called the regression method. Because C. mercuriale is less philopatric than species investigated previously by the regression method we evaluate a refined estimator that may be more applicable for relatively mobile species. Results from simulations and empirical data sets reveal that the new estimator performs better under most situations, except when dispersal is very localized relative to population density. Analysis of the C. mercuriale data extends previous results which demonstrated that demographic and genetic estimates of Nb by the regression method are equivalent to within a factor of two at local scales where genetic estimates are less affected by habitat heterogeneity, stochastic processes and/or differential selective regimes. The corollary is that with a little insight into a species' ecology the pattern of spatial genetic structure provides quantitative information on dispersal rates and/or population densities that has real value for conservation management.

This paper presents the results of the first human trials with the ENOBIO electrophysiology electrode prototype plus the initial results of a new wireless prototype with flexible electrodes based on the same platform. The results indicate that a dry active electrode that employs a CNT array as the electrode interface can perform on a par with traditional "wet" electrodes for the recording of EEG, ECG, EOG and EMG. We also demonstrate a new platform combining wireless technology plus flexible electrodes for improved comfort for applications that take advantage of the dry electrode concept.

Parthenogenesis, the production of offspring without fertilization by a male, is rare in vertebrate species, which usually reproduce after fusion of male and female gametes. Here we use genetic fingerprinting to identify parthenogenetic offspring produced by two female Komodo dragons (Varanus komodoensis) that had been kept at separate institutions and isolated from males; one of these females subsequently produced additional offspring sexually. This reproductive plasticity indicates that female Komodo dragons may switch between asexual and sexual reproduction, depending on the availability of a mate--a finding that has implications for the breeding of this threatened species in captivity. Most zoos keep only females, with males being moved between zoos for mating, but perhaps they should be kept together to avoid triggering parthenogenesis and thereby decreasing genetic diversity.

We have constructed a high density, 13 270-clone cDNA array for the sentinel fish species European flounder (Platichthys flesus), combining clones from suppressive subtractive hybridization and a liver cDNA library; DNA sequences of 5211 clones were determined. Fish were treated by single intraperitoneal injection with 50 micrograms cadmium chloride per kilogram body weight, a dose relevant to environmental exposures, and hepatic gene expression changes were determined at 1, 2, 4, 8, and 16 days postinjection in comparison to saline-treated controls. Gene expression responses were confirmed by real-time reverse transcription polymerase chain reaction (RT-PCR). Blast2GO gene ontology analysis highlighted a general induction of the unfolded protein response, response to oxidative stress, protein synthesis, transport, and degradation pathways, while apoptosis, cell cycle, cytoskeleton, and cytokine genes were also affected. Transcript levels of cytochrome P450 1A (CYP1A) were repressed and vitellogenin altered, real-time PCR showed induction of metallothionein. We thus describe the establishment of a useful resource for ecotoxicogenomics and the determination of the temporal molecular responses to cadmium, a prototypical heavy metal pollutant.

We describe the development and first tests of ENOBIO, a dry electrode sensor concept for biopotential applications. In the proposed electrodes the tip of the electrode is covered with a forest of multi-walled carbon nanotubes (CNTs) that can be coated with Ag/AgCl to provide ionic-electronic transduction. The CNT brush-like structure is to penetrate the outer layers of the skin improving electrical contact as well as increase the contact surface area. In this paper we report the results of the first tests of this concept--immersion on saline solution and pig skin signal detection. These indicate performance on a par with state of the art research-oriented wet electrodes.

Lutzomyia longipalpis, a sibling complex, is the main vector of Leishmania chagasi/infantum. Discriminating between siblings is important as they may differ in vectorial capacity. Lutzomyia longipalpis populations display distinct male sex pheromone chemotypes. We investigated the phylogeographic pattern of variation at microsatellite loci from 11 populations from Brazil and Venezuela related to their male pheromone. Temporal genetic differentiation was mostly not significant at the same site. Spatial genetic differentiation was, however, strong, although there was only a weak relationship between genetic differentiation and the geographic distance separating the samples (r2 < 0.10); geographic separation explained a much greater (54-97%) percentage of the genetic differences among populations when samples with the same pheromone type were analyzed separately. A cluster analysis showed five groups: Lu. cruzi (Brazil) and Lu. pseudolongipalpis (Venezuela) as separate species, two (mostly 9-methyl-germacrene-B) Venezuelan and Brazilian groups, and a very distinct cluster of Brazilian cembrene populations.

Coenagrion mercuriale (Charpentier) (Odonata: Zygoptera) is one of Europe's most threatened damselflies and is listed in the European Habitats directive. We combined an intensive mark-release-recapture (MRR) study with a microsatellite-based genetic analysis for C. mercuriale from the Itchen Valley, UK, as part of an effort to understand the dispersal characteristics of this protected species. MRR data indicate that adult damselflies are highly sedentary, with only a low frequency of interpatch movement that is predominantly to neighbouring sites. This restricted dispersal leads to significant genetic differentiation throughout most of the Itchen Valley, except between areas of continuous habitat, and isolation by distance (IBD), even though the core populations are separated by less than 10 km. An urban area separating some sites had a strong effect on the spatial genetic structure. Average pairwise relatedness between individual damselflies is positive at short distances, reflecting fine-scale genetic clustering and IBD both within- and between-habitat patches. Damselflies from a fragmented habitat have higher average kinship than those from a large continuous population, probably because of poorer dispersal and localized breeding in the former. Although indirect estimates of gene flow must be interpreted with caution, it is encouraging that our results indicate that the spatial pattern of genetic variation matches closely with that expected from direct observations of movement. These data are further discussed with respect to possible barriers to dispersal within the study site and the ecology and conservation of C. mercuriale. To our knowledge, this is the first report of fine-scale genetic structuring in any zygopteran species.

Isoenzyme-based studies have identified 3 taxa/species/'phylogenetic complexes' as agents of visceral leishmaniasis in Sudan: L. donovani, L. infantum and "L. archibaldi". However, these observations remain controversial. A new chitinase gene phylogeny was constructed in which stocks of all 3 putative species isolated in Sudan formed a monophyletic clade. In order to construct a more robust classification of the L. donovani complex, a panel of 16 microsatellite markers was used to describe 39 stocks of these 3 species. All "L. donovani complex" stocks from Sudan were again found to form a single monophyletic clade. L. donovani ss stocks from India and Kenya were found to form 2 region-specific clades. The partial sequence of the glutamate oxaloacetate transaminase (GOT) gene of 17 L. donovani complex stocks was obtained. A single nucleotide polymorphism in the GOT gene appeared to underlie the isoenzyme classification. It was concluded that isoenzyme-based identification is unsafe for stocks isolated in L. donovani endemic areas and identified as L. infantum. It was also concluded that the name L. archibaldi is invalid and that only a single visceralizing species, Leishmania donovani, is found in East Africa.

We describe a possible route for large-scale synthesis of single wall carbon nanotubes (SWNTs) by a combination of the substrate and floating methods. The template prohibits metal particle aggregation, resulting in high-purity SWNT growth, and the three-dimensional floating seeded state of the template induces improved yields of SWNTs in a semi-continuous system. The SWNTs obtained by this method exhibit large variations of texture (isolated tubes and bundles) and a wide range of diameters (0.4-4 nm).

Lutzomyia longipalpis, the main sandfly vector for New World visceral leishmaniasis is a complex of an as yet undefined number of sibling species. At present, there is no consensus on the status (single species vs. species complex) of Brazilian populations. We applied five microsatellite loci to test the hypothesis that L. longipalpis occurs as two sympatric cryptic species in Sobral, Ceará State, Brazil as predicted by male sex pheromone chemotypes described previously for field specimens from this site [S-9-methyl-germacrene-B (9MGB) and a cembrene compound]. Abdominal spot morphology corresponds with pheromone type at this locality (9MGB in '1 spot' males and cembrene in '2 spot' males). Genotype data from 190 wild-caught L. longipalpis specimens collected in October 1999 and April 2001 were used to estimate genetic differentiation between the two sex pheromone populations and sampling dates. No significant (P > 0.05) genetic differences were found between the 1999 and 2001 9MGB samples (theta = 0.018; RST = -0.005), and genetic differentiation was low between the cembrene collections (theta = 0.037, P < 0.05; RST = -0.043, P > 0.05). By contrast, highly divergent allelic frequencies (largely at two microsatellite loci) corresponded to significant (P > 0.05) genetic differentiation (theta = 0.221; RST = 0.215) for all comparisons between samples with different pheromones. When pheromone samples were pooled across sample date, genetic differentiation was high (theta = 0.229; P < 0.001; Nem = 0.84). The allele frequency distribution at each of the five microsatellite loci was similar for males and females from the two collection years. Two of these loci showed highly divergent allele frequencies in the two sex pheromone populations. This was reflected in the highly significant genetic differentiation obtained from the male genotypes, between populations producing different pheromones (theta = 0.229-0.268; P < 0.0001 for the 2001 and theta = 0.254-0.558; P < 0.0001 for the 1999 collections, respectively). Similar results were obtained when the females, assigned to a pheromone type, were included in the analysis. Both a Bayesian analysis of the data set and a population assignment test provided strong evidence for two distinct populations corresponding to pheromone type. Given its genotype, the probability of assigning a 9MGB male to the original 9MGB population was 100% once the two years' collections were pooled. For cembrene-producing '2 spot' males this probability although still high, was lower than for 9MGB males, at 86%. This microsatellite data together with previously reported reproductive isolation between the two Sobral populations confirm that premating barriers are important in speciation of L. longipalpis.

During the course of our screening for squalene synthase inhibitors and Ras farnesylation inhibitors, a novel fungal culture was discovered to produce two structurally unique compounds, CP-225,917 and CP-263,114, as well as zaragozic acid A (squalestatin I). The two compounds are characterized by a bicyclo[4.3.1]dec-1,6-diene core plus two extended alkyl chains. CP-225,917 and CP-263,114 inhibit Ras farnesyl transferase from rat brain with IC50 values of 6 microM and 20 microM, respectively. CP-225,917 inhibits squalene synthase with an IC50 value of 43 microM and CP-263,114 with an IC50 of 160 microM. The producing organism, though not fully classified, exhibits the characteristics of a sterile Phoma species.

The structural formula of the novel antibiotic ionophore CP-54,883 is deduced by systematic reduction from its 13C and 1H NMR spectra. The molecule consists of a polyether ring network and side chain terminated by an aromatic ring containing a phenoxy and two chlorine substituents. Based partly on an assumed analogy to corresponding regions of the similar structure nigericin-A1, the configurations about the sixteen asymmetric carbons are also derived. A belated crystal structure determination confirms, with the exception of one configuration assumed from nigericin-A1, the conclusions drawn, and shows that the anionic charge is in the phenoxy group, rather than the carboxylic acid function.

The novel chlorine-containing acidic polycyclic ether antibiotic CP-54,883 (C41H62O12Cl2) [corrected] is produced by the fermentation of Actinomadura routienii Huang sp. nov. This report presents the taxonomy and the fermentation conditions for the antibiotic-producing culture. The antibiotic is mainly active against Gram-positive bacteria. It protects chickens against Eimeria challenge in vivo and enhances rumen propionic acid in vitro. The physico-chemical properties are also characterized.