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Single Population (single + population)
Selected AbstractsMaladaptation to mental stress mitigated by the adaptive immune system via depletion of naturally occurring regulatory CD4+CD25+ cellsDEVELOPMENTAL NEUROBIOLOGY, Issue 6 2006Hagit Cohen Abstract Peripheral cellular immunity was recently shown to play a critical role in brain plasticity and performance. The antigenic specificity of the participating T cells, however, was not investigated, and nor was their relevance to psychological stress. Here we show, using a mouse model, that adaptive immunity mitigates maladaptation to the acute psychological stress known to trigger abnormal behaviors reminiscent of human post-traumatic stress disorder. Assessment of behavioral adaptation (measured by the acoustic startle response and avoidance behavior) in mice after their exposure to predator odor revealed that maladaptation was several times more prevalent in T cell-deficient mice than in their wild-type counterparts. A single population of T cells reactive to central nervous system (CNS)-associated self-protein was sufficient to endow immune-deficient mice with the ability to withstand the psychological stress. Naturally occurring CD4+CD25+ regulatory T cells were found to suppress this endogenous anti-stress attribute. These findings suggest that T cells specific to abundantly expressed CNS antigens are responsible for brain tissue homeostasis and help the individual to cope with stressful life episodes. They might also point the way to development of immune-based therapies for mental disorders, based either on up-regulation of T cells that partially cross-react with self-antigens or on weakening of the activity of regulatory T cells. © 2006 Wiley Periodicals, Inc. J Neurobiol, 2006 [source] Multi-phase evolution of gnammas (weathering pits) in a Holocene deglacial granite landscape, Minnesota (USA)EARTH SURFACE PROCESSES AND LANDFORMS, Issue 2 2008David Domínguez-Villar Abstract The morphometry of 85 gnammas (weathering pits) from Big Stone County in western Minnesota allows the assessment of the relative ages of the gnamma population. The ratio between maximum and minimum depths is independent of the initial size of the cavity and only depends on the weathering evolution. Therefore, the distribution of depth ratios can be used to assess the gnamma population age and the history of weathering. The asymmetrical distribution of depth ratios measured in Big Stone County forms three distinct populations. When these sets are analyzed independently, the correlation (r2) between maximum and minimum depths is greater than 0·95. Each single population has a normal distribution of depth ratios and the average depth ratios (, -value) for each population are ,1 = 1·60 ± 0·05, ,2 = 2·09 ± 0·04 and ,3 = 2·42 ± 0·08. The initiation of gnamma formation followed the exhumation of the granite in the region. This granite was till and saprolite covered upon retreat of the ice from the Last Glacial Maximum. Nearby outcrops are striated, but the study site remained buried until it was exhumed by paleofloods issuing from a proglacial lake. These Holocene-aged gnammas in western Minnesota were compared with gnammas of other ages from around the world. Our new results are in accordance with the hypothesis that , -values represent the evolution of gnammas with time under temperate- to cold-climate dynamics. Phases of the formation of new gnammas may result from changes in weathering processes related to climate changes. Copyright © 2007 John Wiley & Sons, Ltd. [source] Correlated morphological and colour differences among females of the damselfly Ischnura elegansECOLOGICAL ENTOMOLOGY, Issue 3 2009JESSICA K. ABBOTT Abstract 1.,The female-limited colour polymorphic damselfly Ischnura elegans has proven to be an interesting study organism both as an example of female sexual polymorphism, and in the context of the evolution of colour polymorphism, as a model of speciation processes. 2.,Previous research suggests the existence of correlations between colour morph and other phenotypic traits, and the different female morphs in I. elegans may be pursuing alternative phenotypically integrated strategies. However, previous research on morphological differences in southern Swedish individuals of this species was only carried out on laboratory-raised offspring from a single population, leaving open the question of how widespread such differences are. 3.,The present study therefore analysed multi-generational data from 12 populations, investigating morphological differences between the female morphs in the field, differences in the pattern of phenotypic integration between morphs, and quantified selection on morphological traits. 4.,It was found that consistent morphological differences indeed existed between the morphs across populations, confirming that the previously observed differences were not simply a laboratory artefact. It was also found, somewhat surprisingly, that despite the existence of sexual dimorphism in body size and shape, patterns of phenotypic integration differed most between the morphs and not between the sexes. Finally, linear selection gradients showed that female morphology affected fecundity differently between the morphs. 5.,We discuss the relevance of these results to the male mimicry hypothesis and to the existence of potential ecological differences between the morphs. [source] Clinical dental examinations of 357 donkeys in the UK.EQUINE VETERINARY JOURNAL, Issue 4 2009Part 1: Prevalence of dental disorders Summary Reasons for performing study: Dental disorders have a high prevalence in older donkeys and horses, but the nature and pathogenesis of many of these disorders have yet to be established. Objectives: The identification and determination of the prevalence of important dental disorders in different age groups in a large single population of donkeys, to establish a better understanding of the nature and pathogenesis of these disorders. Methods: A prospective cross-sectional study was performed on the donkey population at The Donkey Sanctuary with detailed oral examinations of 357 donkeys within 7 different age groups (age range 2,53 years) recorded. Results: The prevalence of dental disease in all donkeys was 73%, increasing in prevalence from 28% in the youngest to 98% in the oldest age group. There was an increase in prevalence of commonly recognised dental disorders with increasing age, such as: diastemata (3.8% in youngest to 86% in oldest group); missing teeth (0,56%); overgrown teeth (15,86%); worn teeth (8,84%); displaced teeth (0,38%); and periodontal disease (0,28%). Conclusions: There was a significant increase in the prevalence of dental disorders with increasing age with the largest significant increase for most dental disorders occurring in the 15,20 year age group. Potential significance: Most dental disorders significantly increase in prevalence in the 15,20 year age group and, therefore, prophylactic geriatric dental treatment in donkeys should be commenced from age 15 years. [source] Neuroendocrine Function and Chronic Inflammatory StressEXPERIMENTAL PHYSIOLOGY, Issue 5 2002Michael Harbuz The factors regulating susceptibility and severity of autoimmune diseases are poorly understood. That neuroendocrine factors are critical modulators in this regard is self-evident. For example, there are major gender differences in susceptibility with women at greater risk than men of, for example, rheumatoid arthritis (RA) and multiple sclerosis (MS). The hypothalamo-pituitary-adrenal (HPA) axis has rightly attracted a considerable amount of attention. Of particular interest has been the hypothesis that susceptibility to autoimmune disease may be related to an impaired responsiveness of the HPA axis; that is, an inability to mount an appropriate cortisol response with which to down-regulate the immune system might allow the immune system to rampage unchecked and attack self. This hypothesis links regulation of the release from the adrenal gland of the potent anti-inflammatory glucocorticoids to the disease process. Endogenous glucocorticoids are crucial for the regulation of the severity of the disease process. The hypothesis proposing a link between a hyporesponsive HPA axis and susceptibility to disease is compelling. However, evidence from a number of sources has suggested that this may not be the entire story and alterations in the activity of the HPA axis have not been consistently observed in patients with RA. This review will concentrate on recent findings concerning the HPA axis in determining susceptibility to, and in regulating the severity of, inflammatory processes in autoimmune disease. These studies have revealed that a single exposure to endotoxin can confer protection to subsequent development of inflammation in an arthritis model in both neonatal and adult rats. Behavioural differences within a single population of rats are associated with differences in the plasma corticosterone responses to stress. However, relative hyporesponsiveness is not reflected by an increase in the severity of inflammation. In humans with RA the dexamethasone-corticotrophin-releasing factor (CRF) test has revealed two distinct sub-populations of patients. Studies in patients with MS have shown that this is not related to depression but rather to the severity of the disease. A better understanding of these complex neuroendocrine interactions may lead to novel clinical interventions. [source] Revision of the subgenus Wichuraea (M.Roemer) Baker of BomareaMirbel (Alstroemeriaceae)FEDDES REPERTORIUM, Issue 3-4 2003A. Hofreiter The subgenus Wichuraea of Bomarea (Alstroemeriaceae) was last revised by Baker (1888) as part of his revision of the genus Bomarea. Since then the number of validly published names has increased from seven to recently 50, indicating an urgent need for further revision. Extensive field studies in Peru (A. Hofreiter) and depth investigation of herbarium material have led to new insights into the subgenus. As a result a number of Bomarea species formerly placed under Wichuraea are relocated to another subgenus, a large number of names are placed into synonymy and one species, Bomarea vargasiiHofreiter sp. nova, and one subspecies, Bomareaandimarcana subsp. andimarcanaHofreiter comb. nov. und B. andimarcana subsp. densifoliaHofreiter comb. nov., are newly described. A key to the 16 species is given. Field studies revealed that even taxonomically valuable characters can be remarkably variable, even within a single population. This has demonstrably resulted in a high degree of taxa instability in the group. The typical habit and its variability, preferred habitats and the geographical distribution of each species is presented. Revision der Untergattung Wichuraea (M.Roemer) Baker der Gattung BomareaMirbel (Alstroemeriaceae) Die Untergattung Wichuraea wurde zuletzt von Baker (1888) als Teil der Revision von Bomarea (Alstroemeriaceae) revidiert. Seit dieser Zeit hat die Zahl gültig veröffentlichter Namen von sieben auf 50 zugenommen. Eine Revision erscheint deshalb dringend erforderlich. Die Grundlage für diese Arbeit wurde bei ausführlichen Feldstudien in Peru (A. Hofreiter) und umfangreichen Analysen von Herbarmaterial gelegt. Durch die vorliegende Revision wird die Anzahl der Arten auf 16 reduziert. Ein Teil der bisher zu Wichuraea gestellten Arten gehört zu einer anderen Untergattung, ein weiterer Teil der Namen muss in die Synonymie verwiesen werden. Eine Art, Bomarea vargasiiHofreiter sp. nova, und eine Unterart, Bomarea andimarcana subsp. andimarcanaHofreiter comb. nov. und B. andimarcana subsp. densifoliaHofreiter comb. nov., werden neu beschrieben. Feldstudien ergaben eine hohe Variabilität der Merkmale, selbst innerhalb einer Population. Dies hat z. B. allein bei Bomarea dulcis zu 14 Synonymen geführt. Für jede Art werden die typische Wuchsform und deren Variabilität, die bevorzugten Standorte und die geographische Verbreitung dargestellt. [source] From egg to juvenile in the Bay of Biscay: spatial patterns of anchovy (Engraulis encrasicolus) recruitment in a non-upwelling regionFISHERIES OCEANOGRAPHY, Issue 6 2008XABIER IRIGOIEN Abstract In this study the spatial distribution of eggs, larvae and juveniles of European anchovy (Engraulis encrasicolus) was followed in 2004 and 2005 during three consecutive cruises each year in spring,summer to test what the limits of retention are in a non-upwelling area. Eggs, small larvae and large juveniles were mainly distributed over the shelf, whereas large larvae and small juveniles were found mainly off the shelf. Although overall distributions were similar, the 2 yr differed in that there was more of a coastal distribution of individuals in 2004, whereas in 2005 more individuals were found off the shelf. There were no significant differences in the length,weight relationships for individuals found on and off the shelf or between years. The correspondence in circulation patterns and the lack of difference in the length,weight relationships suggest that a single population is present, larvae drifting off the shelf due to currents and returning as mobile juveniles. Quantile regression analysis of the long-term recruitment index suggests that transport off the shelf may favour good recruitments. This would suggest that in non-upwelling regions the retention area resulting in good recruitment may not be restricted to the shelf. [source] The prevalence of lipodystrophy in an ambulant HIV-infected population: it all depends on the definitionHIV MEDICINE, Issue 3 2001VM Carter Objectives This study's objective was to determine the prevalence of body shape changes and metabolic abnormalities in an ambulant population with HIV infection. Three different definitions of lipodystrophy were used to assess these changes. Patients' anthropometric measures and dual-energy X-ray absorptiometry (DEXA) scans were compared in order to estimate fat distribution in this population. We sought to evaluate potential predictors for lipodystrophy according to each of the three definitions. Methods We performed a cross-sectional study in the outpatient clinic of a tertiary referral hospital in Melbourne, Australia. We enrolled a total of 167 HIV-infected ambulatory patients over 3 months in mid-1998. Data on 159 males, 149 of whom were receiving triple combination antiretroviral therapy, were evaluated. Anthropometric measures, clinical examination, self-report of body shape changes, biochemical measures and DEXA scan were used to assess lipodystrophy and risk factors for cardiovascular disease. Patients described body shape changes in the face, trunk, arms and legs. Laboratory parameters measured included fasting triglyceride (TG), cholesterol, high-density lipoproteins (HDL), glucose, insulin, CD4 cell count and plasma HIV RNA. Current and past antiretroviral therapies were ascertained. Results According to one proposed Australian national definition of lipodystrophy (LDNC), the prevalence of lipodystrophy in this population was 65%. This definition included an objective assessment with major and minor criteria. Patient-defined lipodystrophy (LDP), which involved a subjective assessment of thinning arms and legs and central adiposity, occurred in 19%. Patient-defined lipoatrophy (LAP), which involved a subjective assessment of thinning arms and legs without central adiposity, occurred in 21.3%. No change in body habitus was noted by 37% of the cohort. Hypercholesterolaemia was recorded in 44%, hypertriglyceridaemia in 52% and elevated insulin levels in 23%. Anthropometry was predictive of the per cent total body fat recorded by DEXA scan, but produced consistently lower values. In multivariate analysis, LDP and LAP were significantly associated with stavudine (d4T) use, while LAP was also associated with zidovudine (ZDV) treatment. There were no treatment associations with LDNC. Protease inhibitor (PI) exposure was associated with metabolic changes but not patient perceived body shape changes, while d4T and ZDV exposure was associated with increased triglycerides and reduced peripheral fat stores. Conclusions The prevalence of body shape changes in a single population varied depending on the definition applied. The LDNC definition overestimated body shape abnormalities in comparison with patient perception. LAP was associated with significantly lower fat stores measured by anthropometry and DEXA scan than those identified under the LDNC definition. In contrast to LDNC, LAP was associated with d4T exposure, nucleoside reverse transcriptase inhibitor (NRTI) and ZDV duration of use, but not PI use. Until a consensus definition for lipodystrophy is developed, including agreement on objective measurement and thresholds for abnormality, careful description of the individual components of the syndrome is required to enable cohort comparisons so that predictors of the syndrome can be assessed more accurately and outcome studies made feasible. [source] Critical Evaluation of How the Rosgen Classification and Associated "Natural Channel Design" Methods Fail to Integrate and Quantify Fluvial Processes and Channel Response,JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 5 2007A. Simon Abstract:, Over the past 10 years the Rosgen classification system and its associated methods of "natural channel design" have become synonymous to some with the term "stream restoration" and the science of fluvial geomorphology. Since the mid 1990s, this classification approach has become widely adopted by governmental agencies, particularly those funding restoration projects. The purposes of this article are to present a critical review, highlight inconsistencies and identify technical problems of Rosgen's "natural channel design" approach to stream restoration. This paper's primary thesis is that alluvial streams are open systems that adjust to altered inputs of energy and materials, and that a form-based system largely ignores this critical component. Problems with the use of the classification are encountered with identifying bankfull dimensions, particularly in incising channels and with the mixing of bed and bank sediment into a single population. Its use for engineering design and restoration may be flawed by ignoring some processes governed by force and resistance, and the imbalance between sediment supply and transporting power in unstable systems. An example of how C5 channels composed of different bank sediments adjust differently and to different equilibrium morphologies in response to an identical disturbance is shown. This contradicts the fundamental underpinning of "natural channel design" and the "reference-reach approach." The Rosgen classification is probably best applied as a communication tool to describe channel form but, in combination with "natural channel design" techniques, are not diagnostic of how to mitigate channel instability or predict equilibrium morphologies. For this, physically based, mechanistic approaches that rely on quantifying the driving and resisting forces that control active processes and ultimate channel morphology are better suited as the physics of erosion, transport, and deposition are the same regardless of the hydro-physiographic province or stream type because of the uniformity of physical laws. [source] Ficus racemosa is pollinated by a single population of a single agaonid wasp species in continental South-East AsiaMOLECULAR ECOLOGY, Issue 13 2010N. KOBMOO Abstract High specificity in the Ficus -agaonid wasp mutualism has lead to the assumption of a mostly ,one-to-one' relationship, albeit with some exceptions. This view has been challenged by new molecular data in recent years, but surprisingly little is known about local and spatial genetic structuring of agaonid wasp populations. Using microsatellite markers, we analysed genetic structuring of Ceratosolen fusciceps, the fig wasp pollinating Ficus racemosa, a fig tree species widely distributed from India to Australia. In sampling stretching from the south of China to the south of Thailand we found evidence for only a single pollinating wasp species in continental South-East Asian mainland. We found no evidence for the co-occurrence of cryptic species within our subcontinent sampling zone. We observed no spatial genetic structure within sites and only limited structuring over the whole sampling zone, suggesting that F. racemosa is pollinated by a single population of a single agaonid wasp species all over continental South-East Asia. An additional sample of wasps collected on F. racemosa in Australia showed clear-cut genetic differentiation from the Asian continent, suggesting allopatric divergence into subspecies or species. We propose that the frequent local co-occurrence of sister species found in the literature mainly stems from contact zones between biogeographic regions, and that a single pollinator species over wide areas might be the more common situation everywhere else. [source] Influence of habitat discontinuity, geographical distance, and oceanography on fine-scale population genetic structure of copper rockfish (Sebastes caurinus)MOLECULAR ECOLOGY, Issue 13 2008M. L. JOHANSSON Abstract The copper rockfish is a benthic, nonmigratory, temperate rocky reef marine species with pelagic larvae and juveniles. A previous range-wide study of the population-genetic structure of copper rockfish revealed a pattern consistent with isolation-by-distance. This could arise from an intrinsically limited dispersal capability in the species or from regularly,spaced extrinsic barriers that restrict gene flow (offshore jets that advect larvae offshore and/or habitat patchiness). Tissue samples were collected along the West Coast of the contiguous USA between Neah Bay, WA and San Diego, CA, with dense sampling along Oregon. At the whole-coast scale (~2200 km), significant population subdivision (FST = 0.0042), and a significant correlation between genetic and geographical distance were observed based on 11 microsatellite DNA loci. Population divergence was also significant among Oregon collections (~450 km, FST = 0.001). Hierarchical amova identified a weak but significant 130-km habitat break as a possible barrier to gene flow within Oregon, across which we estimated that dispersal (Nem) is half that of the coast-wide average. However, individual-based Bayesian analyses failed to identify more than a single population along the Oregon coast. In addition, no correlation between pairwise population genetic and geographical distances was detected at this scale. The offshore jet at Cape Blanco was not a significant barrier to gene flow in this species. These findings are consistent with low larval dispersal distances calculated in previous studies on this species, support a mesoscale dispersal model, and highlight the importance of continuity of habitat and adult population size in maintaining gene flow. [source] Testing the role of genetic factors across multiple independent invasions of the shrub Scotch broom (Cytisus scoparius)MOLECULAR ECOLOGY, Issue 22 2007MING KANG Abstract Knowledge of the introduction history of invasive plants informs on theories of invasiveness and assists in the invasives management. For the highly successful invasive shrub Scotch broom, Cytisus scoparius, we analysed a combination of nuclear and chloroplast microsatellites for eight native source regions and eight independent invasion events in four countries across three continents. We found that two exotic Australian populations came from different sources, one of which was derived from multiple native populations, as was an invasive sample from California. An invasive population from New Zealand appeared to be predominantly sourced from a single population, either from the native or exotic ranges. Four invasive populations from Chile were genetically differentiated from the native range samples analysed here and so their source of introduction could not be confirmed, but high levels of differentiation between the Chilean populations suggested a combination of different sources. This extensive global data set of replicated introductions also enabled tests of key theories of invasiveness in relation to genetic diversity. We conclude that invasive populations have similar levels of high genetic diversity to native ranges; levels of admixture may vary across invasive populations so admixture does not appear to have been an essential requirement for invasion; invasive and native populations exhibit similar level of genetic structure indicating similar gene flow dynamics for both types of populations. High levels of diversity and multiple source populations for invasive populations observed here discount founder effects or drift as likely explanations for previously observed seed size differences between ranges. The high levels of genetic diversity, differential and source admixture identified for most exotic populations are likely to limit the ability to source biocontrol agents from the native region of origin of invasive populations. [source] Maintenance of clonal diversity during a spring bloom of the centric diatom Ditylum brightwelliiMOLECULAR ECOLOGY, Issue 6 2005TATIANA A. RYNEARSON Abstract Maintenance of genetic diversity in eukaryotic microbes reflects a synergism between reproductive mode (asexual vs. sexual) and environmental conditions. We determined clonal diversity in field samples of the planktonic marine diatom, Ditylum brightwellii, during a bloom, when cell number increased by seven-fold because of rapid asexual division. The genotypes at three microsatellite loci were determined for 607 individual cell lines isolated during the 11 days of sampling. Genetic diversity remained high during the bloom and 87% of the cells sampled each day were genetically distinct. Sixty-nine clonal lineages were sampled two or more times during the bloom, and two clones were sampled seven times. Based on the frequency of resampled clonal lineages, capture,recapture statistics were used to determine that at least 2400 genetically distinct clonal lineages comprised the bloom population. No significant differences in microsatellite allele frequencies were observed among daily samples indicating that the bloom was comprised of a single population. No sexual stages were observed, although linkage equilibrium at two loci, high levels of allelic and genotypic diversity, and heterozygote deficiencies were all indicative of past sexual reproduction events. At the height of the bloom, a windstorm diluted cell numbers by 51% and coincided with a change in the frequency distribution of some resampled lineages. The extensive clonal diversity generated through past sexual reproduction events coupled with frequent environmental changes appear to prevent individual clonal lineages from becoming numerically dominant, maintaining genetic diversity and the adaptive potential of the population. [source] Characterization of Mauritius parakeet (Psittacula eques) microsatellite loci and their cross-utility in other parrots (Psittacidae, Aves)MOLECULAR ECOLOGY RESOURCES, Issue 4 2009CLAIRE RAISIN Abstract We characterized 21 polymorphic microsatellite loci in the endangered Mauritius parakeet (Psittacula eques). Loci were isolated from a Mauritius parakeet genomic library that had been enriched separately for eight different repeat motifs. Loci were characterized in up to 43 putatively unrelated Mauritius parakeets from a single population inhabiting the Black River Gorges National Park, Mauritius. Each locus displayed between three and nine alleles, with the observed heterozygosity ranging between 0.39 and 0.96. All loci were tested in 10 other parrot species. Despite testing few individuals, between seven and 21 loci were polymorphic in each of seven species tested. [source] Cross-species testing of 27 pre-existing microsatellites in Podarcis gaigeae and Podarcis hispanica (Squamata: Lacertidae)MOLECULAR ECOLOGY RESOURCES, Issue 6 2008ANNA RUNEMARK Abstract We tested 27 microsatellite loci for cross-species amplification in the lacertids Podarcis gaigeae and Podarcis hispanica. We detected 11 and 15 polymorphic loci in the former and the latter species, respectively. In a larger sample of individuals from a single population of each species, the number of alleles ranged from five to 23 in 10 of the polymorphic loci in P. gaigeae, and between four and 13 in nine of polymorphic loci in P. hispanica. Two locus deviated from Hardy-Weinberg equilibrium in P. hispanica. Between 11 and 16 of the 27 loci also amplified successfully in three other Podarcis species. [source] Characterization of microsatellite loci for the littorine snail Bembicium vittatumMOLECULAR ECOLOGY RESOURCES, Issue 6 2008W. J. KENNINGTON Abstract We describe the isolation and development of 17 polymorphic microsatellite loci for the intertidal snail Bembicium vittatum (Gastropoda: Littorinidae). The loci were tested in 46 individuals from a single population situated near the centre of the species distribution. No evidence of linkage disequilibrium was detected between any pair of loci. However, two loci showed significant departures from Hardy,Weinberg expectations. The number of alleles per locus ranged from two to 15. [source] Microsatellite DNA markers for the snow vole (Chionomys nivalis)MOLECULAR ECOLOGY RESOURCES, Issue 3 2008P. WANDELER Abstract A total of 14 dinucleotide microsatellite loci were characterized in the snow vole (Chionomys nivalis). Allelic polymorphism across all loci and 28 individuals representing a single population in the Swiss Alps was high (mean = 10.1 alleles). No significant linkage disequilibrium between pairs of loci and no departure from Hardy,Weinberg equilibrium were found. These loci will be useful for describing mating systems and population structure and to investigate the genetic consequences of a species living in a highly fragmented habitat. [source] PERMANENT GENETIC RESOURCES: Identification and characterization of 14 polymorphic microsatellite loci in the argasid tick Ornithodoros coriaceusMOLECULAR ECOLOGY RESOURCES, Issue 2 2008VERONICA S. KIRCHOFF Abstract Fourteen polymorphic microsatellite loci (di, tetra and di-tetra complexes) were developed for the argasid tick Ornithodoros coriaceus. Polymorphism was assessed for 56 individuals from two populations separated by ~95 km. All loci were polymorphic (X = 7, range 3,17 alleles). All loci were in Hardy,Weinberg equilibrium except for one locus (OrC 8) in a single population (P < 0.00119, after Bonferroni correction for multiple tests). [source] Characterization of polymorphic microsatellites in the Pacific sardine Sardinops sagax sagax (Clupeidae)MOLECULAR ECOLOGY RESOURCES, Issue 4 2004R. T. PEREYRA Abstract We isolated 11 microsatellites from the Pacific sardine Sardinops sagax sagax. The number of alleles and HE among 30 individuals from a single population ranged from four to 24 and from 0.606 to 0.959, respectively. Pacific sardines are a vital economic resource in the northeastern Pacific Ocean, but insufficiently polymorphic loci have limited inferences about its stock structure and genetic variation. The level of variability of these new markers will prove useful in testing hypotheses on the stock-structure and long-term genetic integrity of the species. [source] Isolation and characterization of microsatellite loci in the Caribbean gorgonian Pseudopterogorgia elisabethaeMOLECULAR ECOLOGY RESOURCES, Issue 2 2004Carla Gutiérrez-Rodríguez Abstract We report on the isolation and characterization of five polymorphic microsatellites in the gorgonian Pseudopterogorgia elisabethae from genomic DNA-enriched libraries. Forty-four microsatellites were screened from the libraries with the oligonucleotide probe (CA)12. Five of the screened microsatellites were polymorphic. The levels of polymorphism found in 50 genotyped individuals from a single population suggest that microsatellites are useful tools for the study of genetic variation in gorgonians. These are the first microsatellite loci reported from any gorgonian species. [source] The effect of stellar rotation on colour,magnitude diagrams: on the apparent presence of multiple populations in intermediate age stellar clustersMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY: LETTERS (ELECTRONIC), Issue 1 2009N. Bastian ABSTRACT A significant number of intermediate age clusters (1,2 Gyr) in the Magellanic Clouds appear to have multiple stellar populations within them, derived from bimodal or extended main-sequence turn-offs. If this is interpreted as an age spread, the multiple populations are separated by a few hundred million years, which would call into question the long-held notion that clusters are simple stellar populations. Here, we show that stellar rotation in stars with masses between 1.2 and 1.7 M, can mimic the effect of a double or multiple population, whereas in actuality only a single population exists. The two main causes of the spread near the turn-off are the effects of stellar rotation on the structure of the star and the inclination angle of the star relative to the observer. Both effects change the observed effective temperature, hence colour, and flux of the star. In order to match observations, the required rotation rates are 20,50 per cent of the critical rotation, which are consistent with observed rotation rates of similar mass stars in the Galaxy. We provide scaling relations which can be applied to non-rotating isochrones in order to mimic the effects of rotation. Finally, we note that rotation is unlikely to be the cause of the multiple stellar populations observed in old globular clusters, as low-mass stars (<1 M,) are not expected to be rapid rotators. [source] Usefulness of smears in intra-operative diagnosis of newly described entities of CNSNEUROPATHOLOGY, Issue 6 2009Winny Varikatt The recent edition of World Health Organisation (WHO) Classification of Tumours of the Central Nervous System has incorporated a substantial number of important changes. It has recognised several new entities, many of which are rare. Intra-operative diagnosis of these tumours can be difficult with the freezing artefact that often cripples brain frozen sections. In many instances intra-operative smears are extremely useful adjuvants in neuropathological diagnosis. In this article, we describe intra-operative smear findings of three of the newly described tumours. Their characteristic cytologic features are illustrated along with differentiating features from the common mimics, together with a general approach to brain smears. The entities we discuss here are papillary glioneuronal tumour, papillary tumour of the pineal region and angiocentric glioma. All three tumours share at least focal pseudo-papillary/vasculocentric architecture. Smears from papillary glioneuronal tumour demonstrated dual population of cells in a neuropil background, whereas papillary tumour of the pineal region and angiocentric glioma comprise a single population of cells. These two tumours can further be differentiated based on their cell morphology and background. [source] Breeding habitat selection behaviors in heterogeneous environments: implications for modeling reintroductionOIKOS, Issue 5 2009Jean-Baptiste Mihoub Animal movement and habitat selection behavior are important considerations in ecology, and remain a major issue for successful animal reintroductions. However, simple rules are often used to model movement or focus only on intrinsic environmental cues, neglecting recent insights in behavioral ecology on habitat selection processes. In particular, social information has been proposed as a widespread source of information for habitat evaluation. We investigated the role of explicit breeding habitat selection strategies on the establishment pattern of reintroduced populations and their persistence. We considered local movement at the scale of a single population. We constructed a spatially-implicit demographic model that considered five breeding habitat selection rules: 1) random, 2) intrinsic habitat quality, 3) avoidance of conspecifics, 4) presence of conspecifics and 5) reproductive success of conspecifics. The impact of breeding habitat selection was examined for different release methods under various levels of environmental heterogeneity levels, for both long and short-lived monogamous species. When heterogeneity between intrinsic habitat patch qualities is high, the persistence of reintroduced populations strongly depends on habitat selection strategies. Strategies based on intrinsic quality and conspecific reproductive success lead to a lower reintroduction failure risk than random, conspecific presence or avoidance-based strategies. Conspecific presence or avoidance-based strategies may aggregate individuals in suboptimal habitats. The release of adults seems to be more efficient independent of habitat selection strategy. We emphasize the crucial role of oriented habitat selection behavior and non ideal habitat selection in movement modeling, particularly for reintroduction. [source] A genome-wide scan for signatures of recent selection in Holstein cattleANIMAL GENETICS, Issue 4 2010S. Qanbari Summary The data from the newly available 50 K SNP chip was used for tagging the genome-wide footprints of positive selection in Holstein,Friesian cattle. For this purpose, we employed the recently described Extended Haplotype Homozygosity test, which detects selection by measuring the characteristics of haplotypes within a single population. To assess formally the significance of these results, we compared the combination of frequency and the Relative Extended Haplotype Homozygosity value of each core haplotype with equally frequent haplotypes across the genome. A subset of the putative regions showing the highest significance in the genome-wide EHH tests was mapped. We annotated genes to identify possible influence they have in beneficial traits by using the Gene Ontology database. A panel of genes, including FABP3, CLPN3, SPERT, HTR2A5, ABCE1, BMP4 and PTGER2, was detected, which overlapped with the most extreme P -values. This panel comprises some interesting candidate genes and QTL, representing a broad range of economically important traits such as milk yield and composition, as well as reproductive and behavioural traits. We also report high values of linkage disequilibrium and a slower decay of haplotype homozygosity for some candidate regions harbouring major genes related to dairy quality. The results of this study provide a genome-wide map of selection footprints in the Holstein genome, and can be used to better understand the mechanisms of selection in dairy cattle breeding. [source] Familial associations of rheumatoid arthritis with autoimmune diseases and related conditionsARTHRITIS & RHEUMATISM, Issue 3 2009Kari Hemminki Objective In the era of genome-wide association studies, familial risks are used to estimate disease heritability and the likelihood of candidate-gene identification. This study was undertaken to estimate associations of rheumatoid arthritis (RA) with any of 33 autoimmune diseases and related conditions among parents and offspring, singleton siblings, twins, and spouses. Methods The Multigeneration Register in Sweden was used as a reliable source of information on Swedish families throughout the last century. Data on autoimmune diseases in individual family members were obtained through linkage to the Hospital Discharge Register. The standardized incidence ratio (SIR) was calculated as a measure of the relative risk of RA in family members of patients with RA or any of 33 other autoimmune diseases or related conditions, as compared with the relative risk of RA in those lacking an affected family member. Results Among a total of 447,704 patients, 47,361 were diagnosed as having RA. The SIRs for RA were 3.02 in offspring of affected parents, 4.64 in siblings, 9.31 in multiplex families, 6.48 in twins, and 1.17 in spouses. Significant associations with the familial risk of RA in offspring according to parental proband were observed for ankylosing spondylitis (SIR 2.96), localized scleroderma (SIR 2.40), Sjögren's syndrome (SIR 2.25), systemic lupus erythematosus (SIR 2.13), systemic sclerosis (SIR 1.65), Hashimoto thyroiditis/hypothyroidism (SIR 1.54), pernicious anemia (SIR 1.53), sarcoidosis (SIR 1.40), psoriasis (SIR 1.36), Wegener's granulomatosis (SIR 1.34), and asthma or polymyalgia rheumatica (SIR 1.32). Conclusion This is the first study to compare the familial risks of RA in relation to a large number of autoimmune diseases and related conditions using data from a single population. The high discordant familial risks in this population suggest that there is extensive genetic sharing between RA and the associated diseases. [source] Alpha1A/L -adrenoceptors mediate contraction of the circular smooth muscle of the pig urethraAUTONOMIC & AUTACOID PHARMACOLOGY, Issue 4 2006K. Bagot Summary 1 Sympathetically mediated urethral tone is essential for the maintenance of continence and involves the activation of postjunctional ,1 -adrenoceptors. This study characterizes the ,1 -adrenoceptor subtypes responsible for mediating contraction of the urethral circular smooth muscle of the pig. 2 The potency order of a number of agonists and the affinities of several receptor selective antagonists were determined on pig-isolated circular smooth muscle strips in the presence of cocaine (1 ,m) and corticosterone (10 ,m) to inhibit amine uptake and propranolol (1 ,m) to antagonize , -adrenoceptors. 3 The potency order for agonists was N -[5-(4,5-dihydro-1H-imidazol-2yl)-2-hydroxy-5,6,7,8-tetrahydronaphthalen-1-yl]methanesulphonamide (A61603) > noradrenaline = phenylephrine = M6434 > methoxamine with pEC50 values of 7.3, 5.8, 5.7, 5.6 and 5.0 respectively. 4 The ,1D -adrenoceptor-selective antagonist 8-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-8-azaspiro[4,5]decane-7,9-dione (BMY7378) caused rightward shifts of the concentration,response curves to noradrenaline, yielding a low affinity estimate (6.6) for the urethral receptor. The ,1A -adrenoceptor-selective antagonists, RS100329 and 5-methylurapidil, gave relatively high affinity estimates (9.6 and 8.8 respectively) for this receptor. All three antagonists produced Schild plots with slopes close to unity but did reduce maximum responses at higher concentrations. Prazosin antagonized responses of the urethra to noradrenaline, yielding a mean affinity estimate of 9.0. Although the Schild plot for prazosin again had a slope of unity, this drug also reduced maximum responses to noradrenaline at all concentrations examined (10,100 nm). N -[2-(2-cyclopropylmethoxyphenoxy)ethyl]-5-chloro- ,,, -dimethyl-1H-indole-3-ethanamide (RS17053), which discriminates between responses mediated via ,1A (high affinity) and ,1L -adrenoceptors (low affinity) at concentrations up to 3 ,m, failed to antagonize responses of the urethra. 5 These results suggest that contraction of urethral circular smooth muscle in the pig is mediated via a single population of adrenoceptors with the pharmacological characteristics of the ,1A/L -adrenoceptor, most probably the ,1L -adrenoceptor. [source] Field and experimental evidence that competition and ecological opportunity promote resource polymorphismBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2010RYAN A. MARTIN Resource polymorphism , the occurrence within a single population of discrete intraspecific morphs showing differential resource use , has long been viewed as an important setting for evolutionary innovation and diversification. Yet, relatively few studies have evaluated the ecological factors that favour resource polymorphism. Here, we combine observations of natural populations with a controlled experiment to assess the role of intraspecific competition (specifically, the density of conspecifics) and ecological opportunity (specifically, the range of resources available) on the expression of resource polymorphism in spadefoot toad tadpoles. We found that greater conspecific densities and a greater range of available resources together promoted the expression of resource polymorphism. We conclude that, ecological opportunity, in the form of diverse available resources, along with intraspecific competition, may be a prerequisite for resource polymorphism to evolve, because such polymorphisms require diverse resources onto which each morph can specialize as an adaptive response to minimize competition. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100, 73,88. [source] The role of growth stop as a morphogenetic factor in Mastomys natalensis (Rodentia: Muridae)BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 4 2009CARLO FADDA The present study investigated growth patterns under three different environmental conditions in a single population of the rodent Mastomys natalensis (Rodentia, Muridae) in Morogoro, Tanzania. The study aimed to test whether and how post-weaning ontogenetic processes are affected by different environmental conditions. Morogoro is characterized by a bimodal rainfall pattern, with unreliable peaks occurring in November/December of some years and reliable ones in February to May. We recognized three different generation types. In the first one, the , generation, growth occurred during the dry second half of the year in years when the November/December rains were very poor. The second group (, generation) grew under conditions when these rains were abundant. Finally, the , generation, consisted of animals that were born in the middle of the rainy season in years when there was a continuity between both rainfall peaks. Analyses of size and shape following both Huxley,Jolicoeur and Gould,Mosimann approaches revealed that the three groups differ significantly both in size and shape. In both cases, the importance of the environment in assessing growth trajectories during post-natal ontogenetic processes is apparent. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 97, 791,800. [source] Quantitative steps in symbiogenesis and the evolution of homeostasisBIOLOGICAL REVIEWS, Issue 3 2003S. A. L. M. KOOIJMAN ABSTRACT The merging of two independent populations of heterotrophs and autotrophs into a single population of mixotrophs has occurred frequently in evolutionary history. It is an example of a wide class of related phenomena, known as symbiogenesis. The physiological basis is almost always (reciprocal) syntrophy, where each species uses the products of the other species. Symbiogenesis can repeat itself after specialization on particular assimilatory substrates. We discuss quantitative aspects and delineate eight steps from two free-living interacting populations to a single fully integrated endosymbiotic one. The whole process of gradual interlocking of the two populations could be mimicked by incremental changes of particular parameter values. The role of products gradually changes from an ecological to a physiological one. We found conditions where the free-living, epibiotic and endobiotic populations of symbionts can co-exist, as well as conditions where the endobiotic symbionts outcompete other symbionts. Our population dynamical analyses give new insights into the evolution of cellular homeostasis. We show how structural biomass with a constant chemical composition can evolve in a chemically varying environment if the parameters for the formation of products satisfy simple constraints. No additional regulation mechanisms are required for homeostasis within the context of the dynamic energy budget (DEB) theory for the uptake and use of substrates by organisms. The DEB model appears to be closed under endosymbiosis. This means that when each free-living partner follows DEB rules for substrate uptake and use, and they become engaged in an endosymbiotic relationship, a gradual transition to a single fully integrated system is possible that again follows DEB rules for substrate uptake and use. [source] Efficacy of primary hormone therapy for localized or locally advanced prostate cancer: results of a 10-year follow-upBJU INTERNATIONAL, Issue 3 2006HIDEYUKI AKAZA OBJECTIVE To evaluate the efficacy of primary hormone therapy for localized or locally advanced prostate cancer, by analysing the 10-year survival rates for men with localized or locally advanced prostate cancer treated with primary hormone therapy or prostatectomy. PATIENTS AND METHODS Between February 1993 and March 1995, men with T1b, T1c or T2-3 N0M0 prostate cancer were enrolled. In all, 176 men who had a prostatectomy were assigned to Study 1 and were given adjuvant luteinizing hormone-releasing hormone (LHRH) agonist; 151 men who did not have a prostatectomy were assigned to Study 2 and had LHRH agonist monotherapy or combined androgen blockade. They were followed until death, loss to follow-up, or until the end of the observation period (31 March 2004). We analysed all cases in each study as a single population, and compared Study 1 with Study 2. RESULTS The mean patient ages were 67.2 years in Study 1 and 75.7 years in Study 2. During a median of 10.4 years of follow-up, 20 men in Study 1 and 17 in Study 2 died from prostate cancer, and 21 men in Study 1 and 50 in Study 2 died from other causes. In Study 1, the 10-year overall survival rate was 73% and the 10-year cause-specific survival rate was 86%, vs 41% and 78% in Study 2. Overall survival curves were similar to expected survival curves in both studies. There was no significant difference between studies in cause-specific survival. CONCLUSIONS The progression of prostate cancer was retarded by primary hormone therapy in men with localized or locally advanced prostate cancer. With primary hormone therapy or prostatectomy, the men had a life-expectancy similar to that of the normal population. [source] | ||||||||||||||||||||||||||||||||||