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Differentiation
Kinds of Differentiation Terms modified by Differentiation Selected AbstractsPATHWAYS TO SEX-BASED DIFFERENTIATION IN CRIMINAL COURT SENTENCINGCRIMINOLOGY, Issue 2 2003SAMANTHA JEFFRIES Using a matched sampling method, this research examined the process of sex-based differentiation in sentencing outcomes for 194 men and 194 women, sentenced over a seven-year period in Christchurch, New Zealand. Consistent with past research, our results showed that judicial processing treated women more leniently than men. Path analyses revealed that judges were less likely to sentence women than men to imprisonment terms because of gendered information and decisions made earlier in the judicial process, such as criminal history, length of custodial remands, and pre-sentence recommendations by probation officers. In contrast, judges exercised considerable leniency towards women (compared with men) in setting the length of prison terms, even after statistically controlling for all sex-differentiated factors such as criminal history. Explanations and implications are discussed. [source] ADAPTIVE POPULATION DIFFERENTIATION IN PHENOLOGY ACROSS A LATITUDINAL GRADIENT IN EUROPEAN ASPEN (POPULUS TREMULA, L.): A COMPARISON OF NEUTRAL MARKERS, CANDIDATE GENES AND PHENOTYPIC TRAITSEVOLUTION, Issue 12 2007David Hall A correct timing of growth cessation and dormancy induction represents a critical ecological and evolutionary trade-off between survival and growth in most forest trees (Rehfeldt et al. 1999; Horvath et al. 2003; Howe et al. 2003). We have studied the deciduous tree European Aspen (Populus tremula) across a latitudinal gradient and compared genetic differentiation in phenology traits with molecular markers. Trees from 12 different areas covering 10 latitudinal degrees were cloned and planted in two common gardens. Several phenology traits showed strong genetic differentiation and clinal variation across the latitudinal gradient, with QST values generally exceeding 0.5. This is in stark contrast to genetic differentiation at several classes of genetic markers (18 neutral SSRs, 7 SSRs located close to phenology candidate genes and 50 SNPs from five phenology candidate genes) that all showed FST values around 0.015. We thus find strong evidence for adaptive divergence in phenology traits across the latitudinal gradient. However, the strong population structure seen at the quantitative traits is not reflected in underlying candidate genes. This result fit theoretical expectations that suggest that genetic differentiation at candidate loci is better described by FST at neutral loci rather than by QST at the quantitative traits themselves. [source] CRYPTIC BARRIERS TO DISPERSAL WITHIN A LAKE ALLOW GENETIC DIFFERENTIATION OF EURASIAN PERCHEVOLUTION, Issue 8 2007S. Bergek Gene flow between coexisting or nearby populations normally prevents genetic divergence and local adaptation. Despite this, there are an increasing number of reports of sympatric sister taxa, indicating potential divergence and speciation in the face of gene flow. A large number of such reported cases involve lake-dwelling fish, which are expected to run into few physical barriers to dispersal within their aquatic habitat. However, such cases may not necessarily reflect sympatric speciation if cryptic dispersal barriers are common in lakes and other aquatic systems. In this study, we examined genetic differentiation in perch (Perca fluviatilis L.) from nine locations in a single, small lake (24 km2), using microsatellites. We detected significant genetic differentiation in all but two pairwise comparisons. These patterns were not consistent with divergence by distance or the existence of kin groups. Instead, they suggest that cryptic barriers to dispersal exist within the lake, allowing small-scale genetic divergence. Such an observation suggests that allopatric (or parapatric) divergence may be possible, even in small, apparently homogenous environments such as lakes. This has important consequences for how we currently view evidence from nature for sympatric speciation. [source] POPULATION DIFFERENTIATION IN THE BEETLE TRIBOLIUM CASTANEUM.EVOLUTION, Issue 3 2007We used joint-scaling analyses in conjunction with rearing temperature variation to investigate the contributions of additive, non-additive, and environmental effects to genetic divergence and incipient speciation among 12 populations of the red flour beetle, Tribolium castaneum, with small levels of pairwise nuclear genetic divergence (0.033 < Nei's D < 0.125). For 15 population pairs we created a full spectrum of line crosses (two parental, two reciprocal F1's, four F2's, and eight backcrosses), reared them at multiple temperatures, and analyzed the numbers and developmental defects of offspring. We assayed a total of 219,388 offspring from 5147 families. Failed crosses occurred predominately in F2's, giving evidence of F2 breakdown within this species. In all cases where a significant model could be fit to the data on offspring number, we observed at least one type of digenic epistasis. We also found maternal and cytoplasmic effects to be common components of divergence among T. castaneum populations. In some cases, the most complex model tested (additive, dominance, epistatic, maternal, and cytoplasmic effects) did not provide a significant fit to the data, suggesting that linkage or higher order epistasis is involved in differentiation between some populations. For the limb deformity data, we observed significant genotype-by-environment interaction in most crosses and pure parent crosses tended to have fewer deformities than hybrid crosses. Complexity of genetic architecture was not correlated with either geographic distance or genetic distance. Our results support the view that genetic incompatibilities responsible for postzygotic isolation, an important component of speciation, may be a natural but serendipitous consequence of nonadditive genetic effects and structured populations. [source] ECOLOGICAL DIFFERENTIATION AND DIPLOID SUPERIORITY ACROSS A MOVING PLOIDY CONTACT ZONEEVOLUTION, Issue 1 2007Richard J. A. Buggs Plant polyploid complexes provide useful model systems for distinguishing between adaptive and nonadaptive causes of parapatric distributions in closely related lineages. Polyploidy often gives rise to morphological and physiological changes, which may be adaptive to different environments, but separate distributions may also be maintained by reproductive interference caused by postzygotic reproductive isolation. Here, we test the hypothesis that diploid and descendent polyploid races of the wind-pollinated herb Mercurialis annua, which are found in parapatry over an environmental gradient in northeast Spain, are differentiated in their ecophysiology and life history. We also ask whether any such differences represent adaptations to their different natural environments. On the basis of a series of reciprocal transplant experiments in the field, and experiments under controlled conditions, we found that diploid and polyploid populations of M. annua are ecologically differentiated, but that they do not show local adaptation; rather, the diploids have higher fitness than the polyploids across both diploid- and polyploid-occupied regions. In fact, diploids are currently displacing polyploids by advancing south on two separate fronts in Spain, and previous work has shown that this displacement is being driven to a large extent by asymmetrical pollen swamping. Our results here suggest that ecophysiological superiority of the diploids may also be contributing to their expansion. [source] THE EVOLUTION OF FEMALE MATING PREFERENCES: DIFFERENTIATION FROM SPECIES WITH PROMISCUOUS MALES CAN PROMOTE SPECIATIONEVOLUTION, Issue 10 2006Mark A. McPeek Abstract Females of many species are frequently courted by promiscuous males of their own and other closely related species. Such mating interactions may impose strong selection on female mating preferences to favor trait values in conspecific males that allow females to discriminate them from their heterospecific rivals. We explore the consequences of such selection in models of the evolution of female mating preferences when females must interact with heterospecific males from which they are completely postreproductively isolated. Specifically, we allow the values of both the most preferred male trait and the tolerance of females for males that deviate from this most preferred trait to evolve. Also, we consider situations in which females base their mating decisions on multiple male traits and must interact with males of multiple species. Females will rapidly differentiate in preference when they sometimes mistake heterospecific males for suitable mates, and the differentiation of female preference will select for conspecific male traits to differentiate as well. In most circumstances, this differentiation continues indefinitely, but slows substantially once females are differentiated enough to make mistakes rare. Populations of females with broader preference functions (i.e., broader tolerance for males with trait values that deviate from females most preferred values) will evolve further to differentiate if the shape of the function cannot evolve. Also, the magnitude of separation that evolves is larger and achieved faster when conspecific males have lower relative abundance. The direction of differentiation is also very sensitive to initial conditions if females base their mate choices on multiple male traits. We discuss how these selection pressures on female mate choice may lead to speciation by generating differentiation among populations of a progenitor species that experiences different assemblages of heterospecifics. Opportunities for differentiation increase as the number of traits involved in mate choice increase and as the number of species involved increases. We suggest that this mode of speciation may have been particularly prevalent in response to the cycles of climatic change throughout the Quaternary that forced the assembly and disassembly of entire communities on a continentwide basis. [source] DIFFERENTIATION AMONG POPULATIONS WITH MIGRATION, MUTATION, AND DRIFT: IMPLICATIONS FOR GENETIC INFERENCEEVOLUTION, Issue 1 2006Seongho Song Abstract Populations may become differentiated from one another as a result of genetic drift. The amounts and patterns of differentiation at neutral loci are determined by local population sizes, migration rates among populations, and mutation rates. We provide exact analytical expressions for the mean, variance, and covariance of a stochastic model for hierarchically structured populations subject to migration, mutation, and drift. In addition to the expected correlation in allele frequencies among populations in the same geographic region, we demonstrate that there is a substantial correlation in allele frequencies among regions at the top level of the hierarchy. We propose a hierarchical Bayesian model for inference of Wright's F -statistics in a two-level hierarchy in which we estimate the among-region correlation in allele frequencies by substituting replication across loci for replication across time. We illustrate the approach through an analysis of human microsatellite data, and we show that approaches ignoring the among-region correlation in allele frequencies underestimate the amount of genetic differentiation among major geographic population groups by approximately 30%. Finally, we discuss the implications of these results for the use and interpretation of F -statistics in evolutionary studies. [source] LIFE-HISTORY DIFFERENTIATION AND THE MAINTENANCE OF MONOECY AND DIOECY IN SAGITTARIA LATIFOLIA (ALISMATACEAE)EVOLUTION, Issue 9 2003Marcel E. Dorken Abstract The existence of monoecious and dioecious populations within plant species is rare. This limits opportunities to investigate the ecological mechanisms responsible for the evolution and maintenance of these contrasting sexual systems. In Sagittaria latifolia, an aquatic flowering plant, monoecious and dioecious populations exist in close geographic proximity but occupy distinct wetland habitats differing in the relative importance of disturbance and competition, respectively. Life-history theory predicts contrasting evolutionary responses to these environmental conditions. We propose that the maintenance of monoecy and dioecy in S. latifolia is governed by ecological selection of divergent life-history strategies in contrasting habitats. Here we evaluate this hypothesis by comparing components of growth and reproduction between monoecious and dioecious populations under four conditions: natural populations, a uniform glasshouse environment, a common garden in which monoecious and dioecious populations and their F1 progeny were compared, and a transplant experiment using shaded and unshaded plots in a freshwater marsh. Plants from dioecious populations were larger in size and produced heavier corms in comparison with monoecious populations. Monoecious populations flowered earlier and produced more flowers, clonal ramets, and corms than dioecious populations. The life-history differences between the sexual systems were shown to have a quantitative genetic basis, with F1 progeny generally exhibiting intermediate trait values. Survival was highest for each sexual system in field plots that most closely resembled the habitats in which monoecious (unshaded) and dioecious (shaded) populations grow. These results demonstrate that monoecious and dioecious populations exhibit contrasting patterns of investment in traits involved with growth and reproduction. Selection for divergent life histories between monoecious and dioecious populations of S. latifolia appears to be the principal mechanism maintaining the integrity of the two sexual systems in areas of geographic overlap. [source] A COMPARISON OF FIVE HYBRID ZONES OF THE WETA HEMIDEINA THORACICA (ORTHOPTERA: ANOSTOSTOMATIDAE): DEGREE OF CYTOGENETIC DIFFERENTIATION FAILS TO PREDICT ZONE WIDTHEVOLUTION, Issue 4 2003Mary Morgan-Richards Abstract Tension zones are maintained by the interaction between selection against hybrids and dispersal of individuals. Investigating multiple hybrid zones within a single species provides the opportunity to examine differences in zone structure on a background of differences in extrinsic factors (e.g., age of the zone, ecology) or intrinsic factors (e.g., chromosomes). The New Zealand tree weta Hemideina thoracica comprises at least eight distinct chromosomal races with diploid numbers ranging from 2n = 11 (XO) to 2n = 23 (XO). Five independent hybrid zones were located that involve races differing from one another by a variety of chromosomal rearrangements. The predicted negative correlation between extent of karyotypic differentiation (measured in terms of both percent of genome and number of rearrangements) and zone width was not found. Conversely, the widest zones were those characterized by two chromosome rearrangements involving up to 35% of the genome. The narrowest zone occurred where the two races differ by a single chromosome rearrangement involving approximately 2% of the genome. The five estimates of chromosomal cline width ranged from 0.5 km to 47 km. A comparative investigation of cline width for both chromosomal and mitochondrial markers revealed a complex pattern of zone characteristics. Three of the five zones in this study showed cline concordance for the nuclear and cytoplasmic markers, and at two of the zones the clines were also coincident. Zones with the widest chromosomal clines had the widest mitochondrial DNA clines. It appears that, even within a single species, the extent of karyotypic differentiation between pairs of races is not a good predictor of the level of disadvantage suffered by hybrids. [source] A METAPOPULATION PERSPECTIVE ON GENETIC DIVERSITY AND DIFFERENTIATION IN PARTIALLY SELF-FERTILIZING PLANTSEVOLUTION, Issue 12 2002Pärk. Ingvarsson Abstract., Partial self-fertilization is common in higher plants. Mating system variation is known to have important consequences for how genetic variation is distributed within and among populations. Selfing is known to reduce effective population size, and inbreeding species are therefore expected to have lower levels of genetic variation than comparable out crossing taxa. However, several recent empirical studies have shown that reductions in genetic diversity within populations of inbreeding species are far greater than the expected reductions based on the reduced effective population size. Two different processes have been argued to cause these patterns, selective sweeps (or hitchhiking) and background selection. Both are expected to be most effective in reducing genetic variation in regions of low recombination rates. Selfing is known to reduce the effective recombination rate, and inbreeding taxa are thus thought to be particularly vulnerable to the effects of hitchhiking or background selection. Here I propose a third explanation for the lower-than-expected levels of genetic diversity within populations of selfing species; recurrent extinctions and recolonizations of local populations, also known as metapopulation dynamics. I show that selfing in a metapopulation setting can result in large reductions in genetic diversity within populations, far greater than expected based the lower effective population size inbreeding species is expected to have. The reason for this depends on an interaction between selfing and pollen migration. [source] DIFFERENTIATION OF CURED COOKED HAMS BY PHYSICO-CHEMICAL PROPERTIES AND CHEMOMETRICSJOURNAL OF FOOD QUALITY, Issue 1 2009VITTORIO M. MORETTI ABSTRACT Comparison of physico-chemical and compositional traits was carried out on cooked hams. Deboned fresh pig thighs of three different origins were divided into three batches: 200 pig thighs from the Italian market, H1; 200 from The Netherlands, H2; and 200 from Denmark, H3. Boneless pig thighs were processed under commercial guidelines for production of cooked hams, using brine at 25% level of injection. After processing, 12 cooked hams from each batch were sampled randomly and analyzed for proximate and fatty acid composition. Color measurement was performed on the muscles: biceps femoris, semimembranosus, and semitendinosus. H1 hams showed a higher weight loss and a lower technological yield compared to H2 and H3 hams. Analysis of variance on compositional data showed that H1 hams had a lower moisture/protein ratio, a higher fat content, a lower percentage of, -linolenic, eicosapentaenoic and docosahexaenoic acid, and a higher percentage of myristic and palmitic acids when compared to H2 and H3 hams (P < 0.05). Analysis of color of the three muscles demonstrated that hams from the H1 group had the highest a* values. The application of linear discriminant analysis demonstrated that the use of only four variables allowed to correctly discriminate among groups of cooked hams. PRACTICAL APPLICATIONS The following are the practical applications of this research. The comparison of physico-chemical and compositional traits were carried out on cooked hams. Pig thighs of different origin were processed under commercial guidelines. The physicochemical parameters of cooked hams were defined and showed some differences characterizing the products. [source] INITIAL LEVELS OF DIFFERENTIATION AND REDUCTION IN PSYCHOLOGICAL SYMPTOMS FOR CLIENTS IN MARRIAGE AND FAMILY THERAPYJOURNAL OF MARITAL AND FAMILY THERAPY, Issue 1 2005Suzanne Bartle-Haring Using Bowen Family Systems Theory as a theoretical underpinning, in this study, we investigated the hypothesis that clients with higher levels of differentiation would improve more quickly in therapy than clients with lower levels of differentiation. Hierarchical Linear Modeling was used to analyze the data over nine sessions of therapy in a sample from an on-campus training clinic. The results suggest that there was variation in the initial levels of psychological symptoms and that differentiation was a significant predictor of this variance. The results also suggest that although psychological symptoms decreased over the nine sessions of therapy, there was very little variance in this change. These results are discussed in relation to Bowen Theory. The difficulties of doing this type of research and the lessons learned from this project are also discussed. [source] DIFFERENTIATION OF SUPRAHYOID ACTIVITY PATTERNS DURING SWALLOWING OF UMAMI-TASTING FOODSJOURNAL OF SENSORY STUDIES, Issue 6 2006YOZO MIYAOKA ABSTRACT In the preceding study, the present authors differentiated the activity patterns of the suprahyoid (SH) muscles during pharyngeal swallowing of tasty and tasteless foods by using "TP" values that assigned activity of electromyograms (EMG) to a standardized time scale. In the present study, we calculated not only the TP values but also the InP values (by subtracting the preceding TP-10 values from TP) to analyze activity patterns of the SH EMG during pharyngeal swallowing of foods dissolved in unitary (monosodium glutamate [MSG] and disodium inosine-5,-monophosphate [IMP]) and binary (MSG + IMP) "umami-" tasting solutions of low and high concentration. We found that SH activity patterns differed slightly between low and high concentration of unitary and binary umami-tasting foods, but that SH activity patterns measured while swallowing umami-tasting foods did not differ from those measured while swallowing sweet- or salty-tasting foods, or tasteless food. [source] FIRM OWNERSHIP, PRODUCT DIFFERENTIATION AND WELFARE,THE MANCHESTER SCHOOL, Issue 2 2007YUANZHU LU The purpose of this paper is to study the impact of firm ownership in a differentiated industry. We find there is no effect on product differentiation and welfare due to ownership ratio change between private and state so long as the private (state) ownership in a partially state-owned firm remains at least half (less than half). However, when the private (state) ownership in the partially state-owned firm falls below half (rises more than half), the degree of product differentiation increases (decreases) whereas welfare decreases (increases) in the share of private (state) ownership; and thus the extent of private or state ownership matters. [source] MIXED OLIGOPOLY, PRODUCT DIFFERENTIATION AND COMPETITION FOR PUBLIC TRANSPORT SERVICES,THE MANCHESTER SCHOOL, Issue 3 2006PEDRO CANTOS-SÁNCHEZ This paper explores frequency and pricing decisions in a horizontally and vertically differentiated duopoly when there is competition between means of transport and where one of the firms need not necessarily maximize profits. The private and the mixed duopoly are compared and distortions from the social optimum are identified, both analytically and numerically. A mixed duopoly does not recover the socially optimal solution. However, the presence of a (public) non-profit maximizing operator is a useful measure to get closer to the social optimum. When both operators are (private) profit maximizers, some control measures such as price caps and minimum service availability would reduce the distortions from the social optimum. [source] IDENTIFICATION AND DIFFERENTIATION OF OPAQUE CHINESE OVERGLAZE YELLOW ENAMELS BY RAMAN SPECTROSCOPY AND SUPPORTING TECHNIQUES*ARCHAEOMETRY, Issue 1 2010J. MIAO Using Raman spectroscopy, energy-dispersive X-ray fluorescence and X-ray diffraction, the Pb,Sn,Sb triple oxide yellow and lead,tin yellow have been identified on two pieces of cloisonné enamel (Falangcai) porcelains. Lead,tin yellow and lead antimonate yellow have been identified on famille rose porcelains manufactured before and after 1911, respectively. The replacement of the Pb,Sn,Sb triple oxide yellow by lead,tin yellow and that of the lead,tin yellow by lead antimonate yellow are discussed. [source] HUB-AIRPORT COMPETITION: CONNECTING TIME DIFFERENTIATION AND CONCESSION CONSUMPTION,AUSTRALIAN ECONOMIC PAPERS, Issue 4 2006MING HSIN LIN This paper develops a network model to analyse the economic effects resulting from the non-price competition between the home country's and neighbouring country's hub-airports. Focusing on the trade-off relationship between the length of the connecting time in the hub-airport and the consumption opportunities of the transfer passengers, we demonstrate theoretically that even though the hub-airport bears a cost disadvantage over its rival in providing the hub-airport service, it still has a chance to earn more profits than its rival by the setting of the connecting time. This finding suggests a new methodology for hub-airports that attempt to alleviate price competition. [source] Role of Corridors in Plant Dispersal: an Example with the Endangered Ranunculus nodif lorusCONSERVATION BIOLOGY, Issue 2 2003Florian Kirchner But the few experimental studies supporting the usefulness of corridors have all concerned animal species. We investigated the role of corridors in seed dispersal, studying population genetic and demographic structure in metapopulations of the rare, pond-dwelling, autogamous plant species Ranunculus nodiflorus L. in the Fontainebleau Forest ( France ). Differentiation on three polymorphic isozyme markers was strong among local populations ( ponds ) within metapopulations ( sites ) and moderate among metapopulations. Partial Mantel tests revealed that the connection of ponds through temporarily flooded natural corridors, facilitating seed migration, had a strong negative effect on genetic differentiation between local populations and that a pond was more likely to be colonized when connected by corridors to other occupied ponds. Thus, corridors are probably a key element of landscape structure for metapopulation dynamics in R. nodiflorus. From a conservation perspective, our results suggest that corridors could increase the chance of persistence of plant species living in fragmented habitats by promoting seed dispersal between habitat patches. Resumen: La propuesta de que la migración de organismos entre parches de hábitat puede ser incrementada por corredores ha sido muy discutida en biología de la conservación. Pero los pocos estudios experimentales que apoyan la utilidad de los corredores han sido enfocados hacia especies de animales. Investigamos el papel de los corredores en la dispersión de semillas, estudiando la genética poblacional y la estructura demográfica en metapoblaciones de la especie de planta rara, autógama, habitante de estanques Ranunculus nodiflorus L. en el bosque Fontainebleau ( Francia ). La diferenciación de tres isozimas polimórficas marcadoras fue fuerte entre las poblaciones locales ( estanques ) dentro de metapoblaciones ( sitios ) y fue moderada entre metapoblaciones. Las pruebas parciales de Mantel revelaron que la conexión de estanques a través de corredores naturales inundados facilitando la migración de semillas, tuvo un efecto negativo fuerte en la diferenciación genética entre poblaciones locales y que un estanque fue más probable de ser colonizado cuando se conectaba por corredores con otros estanques ocupados. Por lo tanto, los corredores probablemente son un factor clave de la estructura del paisaje para dinámicas metapoblacionales en R. nodiflorus. Desde una perspectiva de conservación, nuestros resultados sugieren que los corredores podrían incrementar la probabilidad de persistencia de especies de plantas que viven en hábitats fragmentados al promover la dispersión de semillas entre parches de hábitats. [source] Human skeletal muscle cell differentiation is associated with changes in myogenic markers and enhanced insulin-mediated MAPK and PKB phosphorylationACTA PHYSIOLOGICA, Issue 4 2004L. Al-Khalili Abstract Aim:, We hypothesized that myogenic differentiation of HSMC would yield a more insulin responsive phenotype. Methods:, We assessed expression of several proteins involved in insulin action or myogenesis during differentiation of primary human skeletal muscle cultures (HSMC). Results:, Differentiation increased creatine kinase activity and expression of desmin and myocyte enhancer factor (MEF)2C. No change in expression was observed for big mitogen-activated protein kinase (BMK1/ERK5), MEF2A, insulin receptor (IR), hexokinase II, and IR substrates 1 and 2, while expression of glycogen synthase, extracellular signal-regulated kinase 1 and 2 (ERK1/2 MAP kinase) and the insulin responsive aminopeptidase increased after differentiation. In contrast to protein kinase B (PKB)a, expression of (PKB)b increased, with differentiation. Both basal and insulin-stimulated PI 3-kinase activity increased with differentiation. Insulin-mediated phosphorylation of PKB and ERK1/2 MAP kinase increased after differentiation. Conclusion:, Components of the insulin-signalling machinery are expressed in myoblast and myotube HSMC; however, insulin responsiveness to PKB and ERK MAP kinase phosphorylation increases with differentiation. [source] Expression of WASP and Scar1/WAVE1 actin-associated proteins is differentially modulated during differentiation of HL-60 cellsCYTOSKELETON, Issue 4 2003Sophie Launay Abstract The Wiskott-Aldrich Syndrome (WAS) is a disease associated with mutations in the WAS gene and characterised by developmental defects in haematopoietic cells such as myeloid cells. The Wiskott-Aldrich Syndrome protein (WASP)-family includes Scar1 and WASP, which are key regulators of actin reorganization in motile cells. To understand the roles of Scar1 and WASP in myeloid cells and their cytoskeletal control in haematopoietic tissues, we have explored their expression during differentiation of the promyeloid cell line HL-60. Undifferentiated HL-60 cells expressed Scar1 and WASP, and differentiation to neutrophils, induced by retinoic acid or non-retinoid agent treatments, led to a decrease in the level of expression of Scar1, whereas WASP expression was unaffected. Differentiation to monocytes/macrophages, induced by phorbol ester treatment, resulted in a decreased expression of both proteins in the adherent mature cells. Vitamin D3 treatment or cytochalasin D in combination with PMA treatment did not affect WASP expression suggesting that adhesion and cytoskeletal integrity were both essential to regulate WASP expression. Scar1 expression was regulated by differentiation, adhesion, and cytoskeletal integrity. Recently, WASP was found to colocalize with actin in the podosomes. In contrast, we show here that Scar1 did not localize with the podosomes in mature monocytes/macrophages. These observations show for the first time that modulation of Scar1 and WASP expression is a component of the differentiation program of myeloid precursors and indicate that WASP and Scar1 have different roles in mature myeloid cells. Cell Motil. Cytoskeleton 54:274,285, 2003. © 2003 Wiley-Liss, Inc. [source] Adipogenic Differentiation of Human Adipose Tissue,Derived Stem Cells Obtained from Cryopreserved Adipose AspiratesDERMATOLOGIC SURGERY, Issue 7 2010JUNG EUN LEE MS BACKGROUND Although frozen adipose tissue is frequently used for soft tissue augmentation, the viability of frozen fat remains a controversy. The cryopreservation of adipose tissue is important for the future use of adipose-derived stem cells (ASCs) and adipocytes. OBJECTIVE To determine whether optimal cryopreservation techniques with regard to the addition of cryopreservative agents and preservation temperature is essential for the long-term storage of adipose tissue and whether ASCs from cryopreserved adipose aspirates are reliable for use in adipogenic differentiation. MATERIALS AND METHODS Adipose tissue was frozen directly or with cryoprotectant at ,20°C or ,80°C for 1 year. The viability of adipose aspirates and the differentiation of ASCs isolated from adipose tissue were evaluated. RESULTS The viability of adipose aspirates frozen with dimethyl sulfoxide at ,80°C was approximately 87% after 2 months of storage. Moreover, ASCs from adipose tissue stored with cryoprotectant survived successfully for 1 year and differentiated into adipocytes, although ASCs were not detected in the directly frozen adipose tissue. CONCLUSION Adipose tissue cryopreserved with cryoprotectant and stored at optimal temperature might prove to be a reliable source of human ASCs and adipocytes. The authors have indicated no significant interest with commercial supporters. [source] Interview with Dr Tokindo S. Okada in commemoration of the 50th volume of Development, Growth and DifferentiationDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 2008Tokindo S. Okada First page of article [source] The clinical aspects of newborn screening: Importance of newborn screening follow-upDEVELOPMENTAL DISABILITIES RESEARCH REVIEW, Issue 4 2006Philip M. James Abstract The aim of newborn screening is to identify presymptomatic healthy infants that will develop significant metabolic or endocrine derangements if left undiagnosed and untreated. The goal of ultimately reducing or eliminating irreversible sequelae is reached by maximizing test sensitivity of the primary newborn screening that measures specific analytes by a number of methodologies. Differentiation of true from false negatives is accomplished by the test specificity. This review discusses disorders for which, in general, there are available therapies and that are detected by routine and expanded newborn screening. Recommendations are presented for evaluation by a primary care physician, with confirmation by a metabolic or endocrinology specialist. Disorders are organized in tabular format by class of pathway or analyte, with attention to typical clinical presentations, confirmatory biochemical and molecular tests, and therapies. There are numerous challenges in clinical follow-up, including diagnosis and appropriate understanding of the consequences of the disorders. The data required to meet these challenges can be acquired only by large scale longitudinal comprehensive studies of outcome in children identified by newborn screening. Only with such data can newborn screening fully serve families. © 2006 Wiley-Liss, Inc. MRDD Research Reviews 2006;12:246,254. [source] Early lens development in the zebrafish: A three-dimensional time-lapse analysisDEVELOPMENTAL DYNAMICS, Issue 9 2009Teri M.S. Greiling Abstract In vivo, high-resolution, time-lapse imaging characterized lens development in the zebrafish from 16 to 96 hr postfertilization (hpf). In zebrafish, the lens placode appeared in the head ectoderm, similar to mammals. Delamination of the surface ectoderm resulted in the formation of the lens mass, which progressed to a solid sphere of cells separating from the developing cornea at approximately 24 hpf. A lens vesicle was not observed and apoptosis was not a major factor in separation of the lens from the future cornea. Differentiation of primary fibers began in the lens mass followed by formation of the anterior epithelium after delamination was complete. Secondary fibers differentiated from elongating epithelial cells near the posterior pole. Quantification characterized three stages of lens growth. The study confirmed the advantages of live-cell imaging for three-dimensional quantitative structural characterization of the mechanism(s) responsible for cell differentiation in formation of a transparent, symmetric, and refractile lens. Developmental Dynamics 238:2254,2265, 2009. © 2009 Wiley-Liss, Inc. [source] Periostin promotes a fibroblastic lineage pathway in atrioventricular valve progenitor cellsDEVELOPMENTAL DYNAMICS, Issue 5 2009Russell A. Norris Abstract Differentiation of prevalvular mesenchyme into valve fibroblasts is an integral step towards the development of functionally mature cardiac valves. Although clinically relevant, little is known regarding the molecular and cellular mechanisms by which this process proceeds. Genes that are regulated in a spatio-temporal pattern during valve remodeling are candidates for affecting this differentiation process. Based on its expression pattern, we have focused our studies on the role of the matricellular gene, periostin, in regulating the differentiation of cushion mesenchymal cells into valve fibroblasts. Herein, we demonstrate that periostin expression is coincident with and regulates type I collagen protein production, a major component of mature valve tissue. Adenoviral-mediated knock-down of periostin in atrioventricular mesenchyme resulted in a decrease in collagen I protein expression and aberrant induction of myocyte markers indicating an alteration in AV mesenchyme differentiation. In vitro analyses using a novel "cardiotube" assay further demonstrated that expression of periostin regulates lineage commitment of valve precursor cells. In these cells, expression of periostin and collagen I are regulated, in part, by TGF,-3. We further demonstrate that TGF,-3, through a periostin/collagen pathway, enhances the viscoelastic properties of AV cushion tissue surface tension and plays a crucial role in regulating valve remodeling. Thus, data presented here demonstrate that periostin, a TGF,-3 responsive gene, functions as a crucial mediator of chick AV valve maturation via promoting mesenchymal-to-fibroblast differentiation while blocking differentiation of alternative cell types (myocytes). Developmental Dynamics 238:1052,1063, 2009. © 2009 Wiley-Liss, Inc. [source] Cells of all somitic compartments are determined with respect to segmental identityDEVELOPMENTAL DYNAMICS, Issue 4 2005Marlyse Dieuguie Fomenou Abstract Development of somite cells is orchestrated by two regulatory processes. Differentiation of cells from the various somitic compartments into different anlagen and tissues is regulated by extrinsic signals from neighboring structures such as the notochord, neural tube, and surface ectoderm. Morphogenesis of these anlagen to form specific structures according to the segmental identity of each somite is specified by segment-specific positional information, based on the Hox -code. It has been shown that following experimental rotation of presomitic mesoderm or newly formed somites, paraxial mesodermal cells adapt to the altered signaling environment and differentiate according to their new orientation. In contrast, presomitic mesoderm or newly formed somites transplanted to different segmental levels keep their primordial segmental identity and form ectopic structures according to their original position. To determine whether all cells of a segment, including the dorsal and ventral compartment, share the same segmental identity, presomitic mesoderm or newly formed somites were rotated and transplanted from thoracic to cervical level. These experiments show that cells from all compartments of a segment are able to interpret extrinsic local signals correctly, but form structures according to their original positional information and maintain their original Hox expression in the new environment. Developmental Dynamics 233:1386,1393, 2005. © 2005 Wiley-Liss, Inc. [source] Electrocardiogram Differentiation of Benign Early Repolarization Versus Acute Myocardial Infarction by Emergency Physicians and CardiologistsACADEMIC EMERGENCY MEDICINE, Issue 9 2006Samuel D. Turnipseed MD Abstract Objectives: ST-segment elevation (STE) related to benign early repolarization (BER), a common normal variant, can be difficult to distinguish from acute myocardial infarction (AMI). The authors compared the electrocardiogram (ECG) interpretations of these two entities by emergency physicians (EPs) and cardiologists. Methods: Twenty-five cases (13 BER, 12 AMI) of patients presenting to the emergency department with chest pain were identified. Criteria for BER required four of the following: 1) widespread STE (precordial greater than limb leads), 2) J-point elevation, 3) concavity of initial up-sloping portion of ST segment, 4) notching or irregular contour of J point, and 5) prominent, concordant T waves. Additional BER criteria were 1) stable ECG pattern, 2) negative cardiac injury markers, and 3) normal cardiac stress test or angiography. AMI criteria were 1) regional STE, 2) positive cardiac injury markers, and 3) identification of culprit coronary artery by angiography in less than eight hours of presentation. The 25 ECGs were distributed to 12 EPs and 12 cardiologists (four in academic medicine, four in community practice, and four in community academics [health maintenance organization] in each physician group). The physicians were informed of the patients' age, gender, and race, and they then interpreted the ECGs as BER or AMI. Undercalls (AMI misdiagnosed as BER) and overcalls (BER misdiagnosed as AMI) were calculated for each physician group. Results: Cardiologists correctly interpreted 90% of ECGs, and EPs correctly interpreted 81% of ECGs. The proportion of undercalls (missed AMI/total AMI) was 2.8% for cardiologists (95% confidence interval [CI] = 0.09% to 5.5%) compared with 9.7% for EPs (95% CI = 4.8% to 14.6%) (p = 0.02). The proportion of overcalls (missed BER/total BER) was 17.3% for cardiologists (95% CI = 11.4% to 23.3%) versus 27.6% for EPs (95% CI = 20.6% to 34.6%) (p = 0.03). The mean number of years in practice was 19.8 for cardiologists (95% CI = 19 to 20.5) and 11 years for EPs (95% CI = 10.5 to 12.0) (p < 0.001). Conclusions: Although correct interpretation was high in both groups, cardiologists, who had significantly more years of practice, had fewer misinterpretations than EPs in distinguishing BER from AMI electrocardiographically. [source] Effects of retinoic acid upon eye field morphogenesis and differentiationDEVELOPMENTAL DYNAMICS, Issue 3 2001Gerald W. Eagleson Abstract This study describes a whole embryo and embryonic field analysis of retinoic acid's (RA) effects upon Xenopus laevis forebrain development and differentiation. By using in situ and immunohistochemical analysis of pax6, Xbf1, and tyrosine hydroxylase (TH), gene expression during eye field, telencephalon field, and retinal development was followed with and without RA treatment. These studies indicated that RA has strong effects upon embryonic eye and telencephalon field development with greater effects upon the ventral development of these organ fields. The specification and determination of separate eye primordia occurred at stage-16 when the prechordal plate reaches its most anterior aspect in Xenopus laevis. Differentiation of the dopaminergic cells within the retina was also affected in a distinct dorsoventral pattern by RA treatment, and cell type differentiation in the absence of distinct retinal laminae was also observed. It was concluded that early RA treatments affected organ field patterning by suppression of the upstream elements required for organ field development, and RA's effects upon cellular differentiation occur downstream to these organ determinants' expression within a distinct dorsoventral pattern. © 2001 Wiley-Liss, Inc. [source] Differentiation and integration: guiding principles for analyzing cognitive changeDEVELOPMENTAL SCIENCE, Issue 4 2008Robert S. Siegler Differentiation and integration played large roles within classic developmental theories but have been relegated to obscurity within contemporary theories. However, they may have a useful role to play in modern theories as well, if conceptualized as guiding principles for analyzing change rather than as real-time mechanisms. In the present study, we used this perspective to examine which rules children use, the order in which the rules emerge, and the effectiveness of instruction on water displacement problems. We found that children used systematic rules to solve such problems, and that the rules progress from undifferentiated to differentiated forms and toward increasingly accurate integration of the differentiated variables. Asking children to explain both why correct answers were correct and why incorrect answers were incorrect proved more effective than only requesting explanations of correct answers, which was more effective than just receiving feedback on the correctness of answers. Requests for explanations appeared to operate through helping children notice potential explanatory variables, formulate more advanced rules, and generalize the rules to novel problems. [source] How to detect cognitive strategies: commentary on ,Differentiation and integration: guiding principles for analyzing cognitive change'DEVELOPMENTAL SCIENCE, Issue 4 2008Han L.J. Van Der Maas First page of article [source] | ||||||||||||||||||||||||||||||||||||||||||||||